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| Content | ||
| Introduction | 6 | |
| 1 | a common part | 8 |
| 1.1 | Characteristics of rolling stock by brands and mileage | 8 |
| 1.2 | Equipping the repair base | 9 |
| 1.3 | Existing technological process of vehicle maintenance and repair | 10 |
| 1.4 | Analysis of the existing organization of maintenance and repair | 11 |
| 1.5 | Characteristics of vehicle maintenance | 12 |
| 2 | Calculated part | 14 |
| 2.1 | Selection of source data | 14 |
| 2.2 | Calculation of the annual maintenance and repair program | 15 |
| 2.2.1 | Correction of the frequency of maintenance and repair | 15 |
| 2.2.2 | Correction of the labor intensity of TO and TR | 17 |
| 2.2.3 | Determination of the coefficient of technical readiness | 20 |
| 2.2.4 | Calculation of the annual labor intensity of work on TR | 21 |
| 2.2.5 | Calculation of the annual labor intensity of the electrical shop | 22 |
| 2.2.6 | Calculation of the number of production workers | 23 |
| 2.3 | Selection of technological equipment | 25 |
| 2.4 | Payment production area | 26 |
| 3 | Energy part | 27 |
| 3.1 | Electricity demand calculation | 27 |
| 3.2 | Heating calculation | 28 |
| 3.3 | Ventilation calculation | 29 |
| 3.4 | Calculation of water demand | 30 |
| 4 | Technological part | 31 |
| 4.1 | Organization of maintenance and repair | 31 |
| 4.1.1 | Methods for organizing the technological process of vehicle maintenance | 32 |
| 4.1.2 | Choosing a method for organizing the technological process of vehicle maintenance | 33 |
| 4.1.3 | Organization of work of workers at the posts of maintenance of cars. Designing the organization of labor of workers | 34 |
| 4.1.4 | Organization of labor at the posts of TR vehicles | 36 |
| 4.1.5 | Methods for organizing TR vehicles | 37 |
| 4.1.6 | Organization of repair of components and assemblies removed from vehicles | 38 |
| 4.1.7 | Organization of quality control of MOT and TR vehicles | 39 |
| 4.2 | Technological process of work of the site for maintenance and repair of electrical equipment | 40 |
| 4.2.1 | Generator maintenance | 40 |
| 4.2.2 | Start system maintenance | 40 |
| 4.2.3 | Ignition system maintenance | 41 |
| 5 | Economic part | 42 |
| 5.1 | Labor plan | 42 |
| 5.2 | Electrician Pay Planning | 42 |
| 5.3 | Calculation of social contributions | 44 |
| 5.4 | Spare parts and materials costs | 44 |
| 5.5 | List of selected equipment | 45 |
| 5.6 | Depreciation calculation | 47 |
| 5.7 | Calculation of costs for services supporting production | 48 |
| 5.7.1 | Calculation of fuel costs for heating | 48 |
| 5.7.2 | Energy cost calculation | 48 |
| 5.7.3 | Calculation of costs for water supply | 49 |
| 5.8 | Cost plan | 49 |
| 6 | Constructive part | 51 |
| 6.1 | The device and the principle of operation. Drive end cover assembly tool | 51 |
| 6.2 | Strength calculation of parts of a device for assembling lids | 53 |
| 6.2.1 | Calculation of the force acting on the assembled part | 53 |
| 6.2.2 | Calculation of the effort developed by the pneumatic chamber | 54 |
| 6.3 | Calculation of the strength of the hinge joint | 54 |
| 6.3.1 | Checking a finger for a slice | 54 |
| 6.3.2 | Checking the connection for crushing | 54 |
| 7 | Organization of work on labor protection and fire safety | 56 |
| 8 | Nature protection and environmental protection | 61 |
| 8.1 | Influence road transport on the environment | 61 |
| 8.2 | Measures to reduce the harmful effects of vehicles on the environment | 63 |
| List of sources used | 64 |
INTRODUCTION
One of the most important tasks in the field of vehicle fleet operation is further improvement of the organization of maintenance and current repair of vehicles in order to increase their performance and, at the same time, reduce operating costs. The relevance of this problem is confirmed by the fact that many times more labor and money is spent on car maintenance than on its production.
At present, on the basis of scientific and technical progress, the planned preventive system of maintenance and repair of the rolling stock of the timber industry complex as a whole, tested by many years of experience, is being further developed.
As an organization road transport and in the area technical operation automobiles are beginning to apply various economic and mathematical methods of analysis, planning and design. New methods and means of diagnostics are being developed and implemented more and more widely. technical condition and predicting vehicle uptime resources. New types of technological equipment are being created that make it possible to mechanize, and in some cases even automate labor-intensive operations for the maintenance and repair of rolling stock. Modern forms of production management are being developed, which are designed for the use of electronic computers with a further transition to an automated control system.
With the ever-increasing saturation of the national economy with cars, the modern economic system provides for new structural divisions of road transport - auto complexes and production associations, repair and maintenance bases, which potentially contribute to the transition to centralized production of maintenance and repair of cars.
The most important task in any household is the organization of maintenance and current repair of cars. The graduation project is dedicated to this topical topic.
1 General
1.1 Characteristic mobile composition by brands and mileage
The characteristics of the rolling stock available at the enterprise and engaged in the removal of timber (log trucks), transportation of people and goods is shown in Table 1
Table 1 - Characteristics of the rolling stock.
| № | Brand car | Type of car | Year release | General mileage, km |
| 1 | GAZ-3307 | cargo | 2004 | 43769 |
| 2 | GAZ-3307 | cargo | 2004 | 60569 |
| 3 | GAZ-3507 | cargo | 2004 | 55069 |
| 4 | GAZ-66 | cargo | 2002 | 81030 |
| 5 | UAZ-3303 | cargo | 1999 | 97517 |
| 6 | UAZ-31514 | passenger | 2003 | 57099 |
| 7 | MOSKVICH-21412-01 | passenger | 2001 | 109350 |
| 8 | GAZ-3110 | passenger | 2003 | 114455 |
Table 1 shows that the rolling stock has a small variety of brands. This, in turn, increases the quality of spare parts supply and maintenance and repair work.
1.2 Equipment of the repair base
The equipment of the repair base of the enterprise with technologically necessary equipment is shown in Table 2
Table 2 - Technological equipment of the enterprise
1.3 Existing technological process of maintenance and repair
car
For the maintenance of cars in the garage, there is a comprehensive team that performs all types of maintenance and repairs. When performing all types of maintenance, the following operations are performed.
Cleaning the engine from dust and dirt;
By external inspection, they check the absence of leakage of oil, fuel, coolant;
Check the oil level and top up if necessary;
Check the tension of the alternator belt.
Maintenance No. 1 (TO-1)
With TO-1, EO operations are performed, as well as:
Check the oil level and, if necessary, add it to the level of the control hole in the transmission units;
Check and regulate power supply system devices and electrical equipment.
Maintenance No. 2 (TO-2)
With TO-2, the operations TO-1 are performed, as well as:
Air cleaners are washed;
The sediment is drained from the coarse fuel filter;
Change the oil in the engine crankcase.
During the season of service (CO), a check is made rechargeable batteries(checking the level and density of the electrolyte), change the oil and fuel corresponding to the upcoming season.
1.4 Analysis of the existing organization of maintenance and repair
Disassembly and assembly works carried out in the TR zone include the replacement of faulty units, mechanisms and assemblies on the car with serviceable ones, the replacement of faulty parts in them with new or repaired ones, as well as disassembly and assembly work associated with the repair of individual parts.
Of the disassembly and assembly work on the TR, the most typical work is to replace: engines, rear and front axles, gearboxes, radiators, clutches, suspension parts, springs, worn parts in units and assemblies.
To carry out these works, various stands, devices, sets of tools and special tools are used: wrenches, torque wrenches, etc.
The organization of production in the areas of TR ATP is possible on the basis of two methods: universal and specialized posts.
Method of universal posts provides for the performance of work at one post by a brigade of repair workers of various specialties or by highly qualified generalists.
The universal TP post is usually an inspection ditch equipped with equipment that ensures the performance of any TP work on a vehicle.
Specialized post method provides for the performance of work at several posts specialized for performing a certain type of work (on the engine, transmission, etc.).
Each specialized post is equipped with equipment in accordance with the nature of the work performed on it. The specialization of TR posts makes it possible to mechanize the labor intensity of work as much as possible, reduce the need for equipment of the same type, improve working conditions, employ less skilled workers, and improve the quality of work and labor productivity by 20–40%.
An example of a layout solution for the location of equipment at a dead-end post and the organization of post work can be the one shown in Fig. 3.2 approximate layout of a universal post in the area of car maintenance.
Work stations for replacement and TR engines trucks , as a rule, they are organized on isolated standard inspection dead-end ditches. Specialized work stations for TR engines can be of two types: for removing and installing engines and for TR engines on cars. They differ in the equipment and the number of simultaneously working performers.
It is advisable to locate a working station for TR engines near the engine (aggregate) section, next to the section for assembling, checking and running-in engines. It is advisable to equip the post with diagnostic equipment to ensure control and adjustment after the work of the TR. Units and engine parts removed during routine repair (block head, water pump, valves, springs, etc.) are cleaned and repaired in the engine (aggregate) section.
Rice. 3.2. Approximate technological layout of a universal post in the area of current car repair:
1 - overhead crane; 2 - a rack for accessories; 3 - bump wheel; 4 - nut runner for spring ladder nuts; 5 - stand for equipment and units; 6 - trolley for removing and installing wheels; 7 - removal device exhaust gases; 8 - air-dispensing column; 9 - nutrunner for wheel nuts; 10 - trolley for units; 11 - rotating rack for normals; 12 - cabinet for instruments and tools; 13 - trolley for replacing bridges; 14 - oil dispensing tank; 15 - a container for draining the oil; 16 - locksmith's vice; 17 - transition bridge; 18 , 26 - Chest for cleaning materials; 19 - a chest for waste; 20 - locksmith's workbench; 21 - bath for washing parts; 22 - limiting stops; 23 - non-groove lift; 24 - hinged funnel for draining oils; 25 - a box for fasteners and tools; 27 - ditch lift with wrench
Work posts specializing in the repair of other units and systems are organized similarly to universal posts, but with equipment specialization.
The specificity of the TR of gas equipment requires the creation of specialized posts and the organization of work on them by special repair workers.
Among the specialized posts, posts are created and equipped for the performance of a number of diagnostic and adjustment work. The need for their organization is caused by the use of special diagnostic equipment when performing TR work. Such posts, organized on the basis of economic considerations and improving the quality of work, include:
- posts for diagnostics and adjustment of car brakes, equipped with roller brake testers;
- posts for diagnostics and adjustment of car wheel alignment angles, equipped with optical stands.
With regular maintenance, the parameters of the technical condition of the vehicle are maintained within the specified limits. However, due to wear of parts, breakdowns and other reasons, the resource of the car, its units or mechanisms is consumed, and a moment comes when the car can no longer be used normally. In other words, its limiting state sets in, which cannot be eliminated by preventive maintenance methods, but requires the restoration of the eliminated operability - repair.
The main purpose of technical repair is to eliminate the malfunctions or failures that have arisen in the car, its units and restore their performance.
During technical repair, the following types of work are performed:
disassembly and assembly;
mechanical fittings;
copper;
welding and tin-making;
electrical;
tire repair;
adjusting and some other types.
Car repair work is laborious and sometimes requires significant financial costs. To carry them out, sometimes partial or complete disassembly of the product is required for the installation or replacement of parts, the use of complex precision, welding, painting and other equipment.
The main basic parts and assemblies include the engine block, gearbox, drive axle, steering gear, beam front axle or a cross member of an independent suspension, body body. During technical repair, dismantling, installation and restoration work can be carried out both for the vehicle as a whole and for its individual units, systems and assemblies. Along with this, during technical repairs, they restore, replace and eliminate various damages parts, deformations and distortions of the body and its parts, soldering, boring, painting, anti-corrosion protection, replacement of glasses, fittings, etc.
Technical repair can be current and capital.
During routine repairs, they eliminate the emerging failures and malfunctions, contribute to the fulfillment of the established mileage standards before overhaul with minimal downtime. The need for such repairs is established during control inspections, which are performed during all types of maintenance, as well as at the request of the driver or car owner. They carry out routine repairs at service stations, in auto repair shops, motor transport divisions, auto complexes, replacing at the restored units piston rings, bearing shells crankshaft, wheel hub bearings, springs and spring pins, ball pins of the steering gear, perform grinding in valves, soldering the radiator, etc.
Overhaul is designed to restore the performance of vehicles and their units in order to ensure the established overhaul mileage, subject to regular technical inspection, maintenance and correct operation... The rates of overhaul mileage of overhauled units, as a rule, are assigned at the rate of at least 80% of the mileage rate for new units and cars. The technical condition and completeness of the car and its units must comply with the unified technical conditions for delivery and delivery from overhaul.
Overhaul of cars should be carried out by specialized auto enterprises with complete disassembly into units, and units into parts. The need for major repairs is determined by a special commission, which is appointed by the head of the car company.
Units are not accepted for overhaul if, when diagnosing or inspecting them, it turned out that the rules for handing over for repair were violated during registration and if the defects of the basic parts cannot be restored. Aggregates are sent for overhaul if it is necessary to repair the base part, deterioration of the technical condition of the unit due to the wear of most parts, and when a complete disassembly of the unit is required to repair the base part.
At overhaul the unit is completely disassembled, malfunctions are identified, the necessary parts, components are restored or replaced, after which the unit is assembled, adjusted and tested.
To determine the technical condition of the car and the amount of repair work, various diagnostic tools are used. If, when diagnosing, it is not possible to determine the technical condition or malfunction of components and assemblies, they are removed from the car and disassembled to determine the amount of work. The results of the check are entered into the card of the control and diagnostic inspection of the car.
Cars are repaired individually or in aggregate way.
An individual repair method provides for the dismantling of damaged units, their restoration, repair and installation on a car. With this repair method, downtime can be significant.
Aggregate repair method significantly reduces downtime, since in this case, repairs are performed by replacing faulty units and assemblies with serviceable ones. The aggregate method, as a rule, is repaired at specialized enterprises and workshops, which increases the efficiency of the repair.
4.2 Harmful factors
NATURAL AND ARTIFICIAL LIGHTING
Light is a natural condition of human life, necessary for
preservation of health and high performance labor, and based on
the work of the visual analyzer, the thinnest and most versatile organ
Light is electromagnetic waves visible to the eye
optical range 380-760 nm long, perceived by the reticular shell
visual analyzer.
V production premises 3 types of lighting are used:
natural (its source is the sun), artificial (when
only artificial light sources are used); combined or
mixed (characterized by the simultaneous combination of natural and
artificial lighting).
Combined lighting is used when only
natural light cannot provide the necessary conditions for
performing production operations.
The current building codes and regulations provide for two
artificial lighting systems: general lighting system and
combined lighting.
Natural light is created by natural light sources direct
solid rays and diffuse light of the sky (from the sun's rays,
scattered by the atmosphere). Natural light is biodegradable
the most valuable type of lighting to which the eye is most adapted
person.
In production facilities, the following types of natural
lighting: lateral - through light openings (windows) in the outer walls; top -
through skylights in the ceilings; combined - through light
lights and windows.
In buildings with insufficient natural light, a combined
lighting - a combination of natural and artificial light. Artificial
lighting in the combined system can function constantly (in zones with
insufficient natural light) or turn on when
Artificial lighting at industrial enterprises is carried out
incandescent and gas-discharge lamps, which are sources of
artificial light.
General and local lighting is used in industrial premises.
General - for lighting the entire room, local (in a combined system)
To increase the illumination of only work surfaces or individual parts
equipment.
The use of not only local lighting is not allowed.
From the point of view of occupational health, the main lighting characteristic is
is the illuminance (E), which is the distribution
luminous flux (F) on a surface area (S) and can be expressed
formula E = F / S.
Luminous flux (F) - power of radiant energy, estimated by
the visual sensation it produces. Measured in lumens (lm).
In the physiology of visual perception, great importance is attached not
incident flow, and the level of brightness of illuminated industrial and other
objects, which is reflected from the illuminated surface in the direction of the eye.
Visual perception is determined not by illumination, but by brightness, under
which understand the characteristic of luminous bodies, equal to the ratio of the intensity of the light
in any direction to the area of the projection of the luminous surface on
plane perpendicular to this direction. Brightness is measured in
nitah (nt). The brightness of illuminated surfaces depends on their luminous properties,
the degree of illumination and the angle at which the surface is viewed.
Luminous intensity - the luminous flux spreading inside the solid angle,
equal to 1 steradiant. The unit of luminous intensity is the candela (cd).
The luminous flux incident on the surface is partially reflected,
absorbed or passed through the illuminated body. Therefore, the light
the properties of the illuminated surface are also characterized by the following
coefficients:
reflection coefficient - the ratio of the luminous flux reflected by the body to
falling;
transmittance - the ratio of the luminous flux passed through
Wednesday to the falling;
absorption coefficient - the ratio of the light flux absorbed by the body
to the falling.
The required illumination levels are standardized in accordance with SNiP 23-
05-95 "Natural and artificial lighting" depending on the accuracy
the production operations performed, the luminous properties of the working surface
and the part in question, the lighting system. "
Hygienic requirements reflecting the quality of production
lighting include:
uniform distribution of brightness in the field of view and limitation of shadows;
limiting direct and reflected glitter;
limitation or elimination of fluctuations in the luminous flux.
Even distribution of brightness in the field of view is essential
to maintain human performance. If constantly in sight
there are surfaces that differ significantly in brightness (illumination),
then when looking from a bright to a dimly lit surface of the eyes
forced to readjust. Frequent readaptation leads to development
eye fatigue and makes it difficult to perform production operations.
The degree of unevenness is determined by the coefficient of unevenness -
the ratio of the maximum illumination to the minimum. The higher the accuracy
work, the less should be the coefficient of unevenness.
Excessive blinding brightness (brilliance) - a property of luminous
surfaces with increased brightness to disrupt the conditions of comfortable vision,
impair contrast sensitivity or simultaneously render both of these
actions.
Luminaires - light sources enclosed in fittings - are designed
for correct distribution of light flux and protection of eyes from excessive
brightness of the light source. The armature protects the light source from mechanical
damage, as well as smoke, dust, soot, moisture, provides fastening and
connection to power supply.
According to the light distribution, the luminaires are subdivided into luminaires
direct, scattered and reflected light. Direct light luminaires over
80% of the luminous flux is directed to the lower hemisphere due to the internal
reflective enamel surface. Scattered light luminaires emit
luminous flux in both hemispheres: some - 40-60% of the luminous flux downward, others
60-80% up. Luminaires of reflected light more than 80% of luminous flux
are directed upward to the ceiling, and the light reflected from it is directed downward into
working area.
To protect the eyes from the brilliance of the luminous surface of the lamps, it serves
protective corner of the luminaire - the angle formed by the horizontal
from the surface of the lamp (edge of the luminous filament) and a line passing through
the edge of the reinforcement.
Luminaires for fluorescent lamps mainly have direct light
distribution. The protective angle serves as a measure of protection against direct glitter,
screening grilles, diffusers made of transparent plastic or glass.
With the help of appropriate placement of lamps in the volume of the working
a lighting system is created in the premises. General lighting can be
uniform or localized. General arrangement of luminaires (in
rectangular or staggered) to create rational illumination
performed when performing the same type of work throughout the room, with a large
density of workplaces (assembly shops in the absence of a conveyor,
woodworking, etc.) General localized lighting is provided
to provide illumination in a given plane at a number of workplaces
(thermal furnace, blacksmith's hammer, etc.), when near each of them
an additional lamp is installed (for example, oblique light), as well as when
performance of works of different nature in the workshop areas or if there is
shading equipment.
Local lighting is designed to illuminate the work surface and
can be stationary and portable, lamps are more often used for it
incandescent, as fluorescent lamps can cause stroboscopic
Emergency lighting is installed in production areas and on
open area for the temporary continuation of work in the event of an emergency
shutdown of working lighting (common network). It should not
less than 5% of the illumination from the standardized for the general lighting system.
PRODUCTION VIBRATION
Long-term exposure to high vibration levels on the human body
leads to the development of premature fatigue, decreased productivity
labor, an increase in morbidity and often to the emergence of professional
pathology - vibration disease.
Vibration is the mechanical vibrational motion of a system with elastic
Vibration by the method of transmission to a person (depending on the nature
contact with sources of vibration) are conventionally subdivided into:
local (local), transmitted to the hands of the worker, and general,
transmitted through supporting surfaces to the human body in a sitting position
(buttocks) or standing (soles of the feet). General vibration in hygienic practice
rationing is referred to as workplace vibration. In production
conditions often there is a combined effect of local and general vibration.
In terms of its physical characteristics, industrial vibration has
rather complex classification.
By the nature of the spectrum, vibration is divided into narrowband and
broadband; in frequency composition - to low-frequency with a predominance
maximum levels in octave bands of 8 and 16 Hz, mid-frequency - 31.5 and
63 Hz, high-frequency - 125, 250, 500, 1000 Hz - for local vibration;
for vibration of workplaces - respectively 1 and 4 Hz, 8 and 16 Hz, 31.5 and
According to the time characteristics, vibration is considered: constant, for
which the value of vibration velocity changes by no more than 2 times (by 6 dB)
during the observation time not less than 1 min; variable, for which the value
vibration velocity changes by at least 2 times (by 6 dB) per time
observation for at least 1 min.
Unstable vibration, in turn, is subdivided into fluctuating in
time for which the level of vibration velocity is continuously changing in
time; intermittent when the operator is in contact with vibration during operation
is interrupted, and the duration of the intervals during which there is
contact is more than 1 s; pulse, consisting of one or
several vibrational influences (for example, shocks), each
duration less than 1 s at a repetition rate of less than 5.6 Hz.
Industrial sources of local vibration are manual
mechanized machines for percussion, percussion-rotary and rotary
actions with pneumatic or electric drive.
Impact tools are based on the principle of vibration. To them
include riveting, chipping, jackhammers, pneumatic rammers.
Impact rotary action machines include pneumatic and
electric rock drills. Used in the mining industry,
mainly for drilling and blasting production.
Manual mechanized machines of rotary action include
grinding, drilling machines, electric and petrol-powered saws.
Local vibration also occurs when grinding, emery,
grinding, polishing work performed on stationary machines with
manual supply of products; when working with hand tools without motors,
for example, straightening work.
The main regulatory legal acts governing the parameters
industrial vibrations are:
Sanitary norms and rules when working with machines and equipment that create local vibration transmitted to the hands of workers "
and "Sanitary Vibration Standards for Workplaces" No. 3044-84.
Currently, about 40 state standards regulate
technical requirements for vibration machines and equipment, systems
vibration protection, methods of measurement and assessment of vibration parameters and others
The most effective means of protecting a person from vibration is
elimination of direct contact with vibrating equipment.
This is done through the use of remote control, industrial
robots, automation and replacement of technological operations.
Reducing the adverse effects of vibration in hand-held mechanized
tools per operator is achieved by technical solutions:
a decrease in the intensity of vibration directly at the source (due to
design improvements);
means of external vibration protection, which are
elastic damping materials and devices placed between the source
vibration and hands of a human operator.
In the complex of measures, an important role is assigned to the development and implementation of
scientifically grounded regimes of work and rest. For example, the total time
contact with vibration should not exceed 2/3 of the duration of the working
active rest, carrying out physioprophylactic procedures,
industrial gymnastics in a special complex.
In order to prevent the adverse effects of local and general
vibrations workers must use personal protective equipment:
mittens or gloves (GOST 12.4.002-74. "Personal protective equipment
hands from vibration. General requirements "); safety footwear (GOST 12.4.024-76." Footwear
special vibration protection ").
At enterprises with the participation of sanitary and epidemiological supervision of medical institutions, services
labor protection, a specific set of medical
biological preventive measures, taking into account the nature
impacting vibration and associated factors of the working environment.
6. ELECTROMAGNETIC, ELECTRIC AND MAGNETIC FIELDS. STATIC
ELECTRICITY
Dangerous exposure workers can be affected by electromagnetic fields
radio frequencies (60 kHz-300 GHz) and electric fields of industrial frequency (50
The source of industrial frequency electric fields are
live parts of existing electrical installations (power lines,
inductors, capacitors of thermal installations, feeder lines, generators,
transformers, electromagnets, solenoids, impulse installations
semi-cycle or capacitor type, cast and sintered
magnets, etc.). Long-term exposure to an electric field on the body
a person can cause a violation of the functional state of the nervous and
cardiovascular systems. This is expressed in increased fatigue,
decrease in the quality of performance of work operations, pain in the heart area,
changes in blood pressure and heart rate.
The main types of collective protection against exposure
electric fields of power frequency currents are shielding
devices - component electrical installation designed for
personnel protection in open switchgears and on air
power lines.
A shielding device is necessary when inspecting equipment and when
operational switching, monitoring the production of work. Structurally
shielding devices are designed in the form of canopies, awnings or
partitions made of metal ropes, rods, nets.
Portable screens are also used for maintenance work
electrical installations in the form of removable canopies, awnings, partitions, tents and
Shielding devices must have a corrosion-resistant coating and
grounded.
The sources of radio frequency electromagnetic fields are:
in the range 60 kHz - 3 MHz - unshielded items of equipment for
induction metal processing (hardening, annealing, melting, brazing, welding and
etc.) and other materials, as well as equipment and instruments used in
radio communication and radio broadcasting;
in the range 3 MHz - 300 MHz - unshielded items of equipment and
devices used in radio communication, broadcasting, television, medicine, and
also equipment for heating dielectrics (welding of plastic compounds, heating
plastics, gluing wood products, etc.);
in the range of 300 MHz - 300 GHz - unshielded items of equipment and
devices used in radar, radio astronomy, radio spectroscopy,
physiotherapy, etc.
Long-term exposure to radio waves on various body systems
a person's consequences have diverse manifestations.
Most characteristic when exposed to radio waves of all ranges
are deviations from the normal state of the central nervous system and
human cardiovascular system. Subjective sensations of the irradiated
staff complain of frequent headache, drowsiness or general
insomnia, fatigue, weakness, excessive sweating, memory loss,
absent-mindedness, dizziness, darkening of the eyes, unreasonable feeling
anxiety, fear, etc.
To ensure the safety of work with sources of electromagnetic waves
systematic control of the actual standardized parameters is carried out for
workplaces and places of possible location of personnel. Control
is carried out by measuring the strength of the electric and magnetic fields, and
also by measuring the energy flux density according to approved methods
Ministry of Health.
Protection of personnel from exposure to radio waves is used for all types of
work if the working conditions do not meet the requirements of the standards. This protection
carried out in the following ways and means:
matched loads and stress-relieving power absorbers
and the field density of the energy flux of electromagnetic waves;
shielding the workplace and radiation source;
rational placement of equipment in the working room;
selection of rational operating modes of equipment and working regime
staff;
the use of preventive protection means.
Most efficient use of matched loads and absorbers
power (antenna equivalents) during manufacturing, tuning and testing
separate blocks and complexes of equipment.
Effective remedy protection against electromagnetic radiation
is the shielding of radiation sources and the workplace with
screens that absorb or reflect electromagnetic energy. The choice of const
Screen rudiments depend on the nature of the technological process, power
source, wavelength range.
radiation (leakage from circuits in microwave transmission lines, from cathode leads
magnetrons and others), as well as in cases where the electromagnetic
energy does not interfere with the operation of the generating set, or
radar station. In other cases, as a rule, apply
absorbing screens.
For the manufacture of reflective screens, materials with high
electrical conductivity, for example metals (in the form of solid walls) or
cotton fabrics with a metal base. Solid metal
screens are the most effective and even at a thickness of 0.01 mm provide
attenuation of the electromagnetic field by about 50 dB (100,000 times).
For the manufacture of absorbing screens, materials with poor
electrical conductivity. Absorbent screens are manufactured as extruded
rubber sheets of special composition with conical solid or hollow
spikes, as well as in the form of porous rubber plates filled with carbonyl
iron, with a pressed-in metal mesh. These materials are glued
onto the frame or surface of the radiating equipment.
Important preventive measure to protect against electromagnetic
exposure is the fulfillment of the requirements for the placement of equipment and for
creation of premises in which there are sources of electromagnetic
radiation.
Protection of personnel from overexposure can be achieved by
placement of HF, UHF and UHF generators, as well as radio transmitters in
specially designed premises.
Screens of radiation sources and workplaces are blocked with disconnecting
devices, which makes it possible to exclude the operation of emitting equipment when
open screen.
Permissible levels of exposure to workers and requirements for conducting
workplace control for electric fields of industrial frequency
are set out in GOST 12.1.002-84, and for electromagnetic fields of radio frequencies - in
GOST 12.1.006-84.
In enterprises, it is widely used and obtained in large quantities
substances and materials with dielectric properties that
contributes to the generation of static electricity.
Static electricity is generated by friction
(contact or separation) of two dielectrics against each other or
dielectrics about metals. At the same time, rubbing substances can accumulate
electrical charges that easily drain into the ground if the body is
conductor of electricity and it is grounded. On dielectrics, electrical
charges are held for a long time, as a result of which they received
the name of static electricity.
The process of the emergence and accumulation of electric charges in substances
called electrification.
The phenomenon of static electrification is observed in the following main
in the flow and when splashing liquids;
in a stream of gas or steam;
upon contact and subsequent removal of two solid dissimilar bodies
(contact electrification).
A discharge of static electricity occurs when the tension
electrostatic field above the surface of a dielectric or conductor,
due to the accumulation of charges on them, reaches the critical (breakdown)
magnitudes. For air, the breakdown voltage is 30 kB / cm.
People working in the area affected by the electrostatic field,
there are various complaints: irritability, headache,
sleep disturbance, loss of appetite, etc.
The permissible levels of the intensity of electrostatic fields are established
GOST 12.1.045-84 "Electrostatic fields. Permissible levels at workers
places and requirements for the control "and Sanitary and hygienic
norms of permissible intensity of the electrostatic field (No. 1757-77).
These regulations apply to electrostatic
fields generated during the operation of high voltage electrical installations
direct current and electrification of dielectric materials, and set
permissible levels of intensity of electrostatic fields at workplaces
personnel, as well as general requirements for control and means
Allowable levels of intensity of electrostatic fields
set depending on the time spent at the workplace.
Maximum permissible level of intensity of electrostatic fields
set equal to 60 kV / m for 1 hour.
When the intensity of electrostatic fields is less than 20 kV / m, the time
exposure to electrostatic fields is not regulated.
In the voltage range from 20 to 60 kV / m, the permissible residence time
personnel in an electrostatic field without protective equipment depends on
specific level of tension in the workplace.
ESD precautions are intended to prevent
the occurrence and accumulation of static electricity charges, the creation
conditions for the dispersion of charges and the elimination of the danger of their harmful effects.
The main protection measures include:
preventing the accumulation of charges on electrically conductive parts
equipment, which is achieved by grounding equipment and communications, on
which charges may appear (devices, tanks, pipelines,
conveyors, unloading devices, overpasses, etc.); decrease
electrical resistance of the processed substances; decline
intensity of charges of static electricity. Is achieved
appropriate selection of the speed of movement of substances, with the exception of
spraying, crushing and spraying substances, drainage of electrostatic
charge, selection of friction surfaces, cleaning of combustible gases and liquids from
impurities;
drainage of static electricity charges that accumulate on people.
Eliminates the danger of electrical discharges that can cause
ignition and explosion of explosive and fire hazardous mixtures, as well as harmful
the effect of static electricity on a person. The main measures of protection
are: the device of electrically conductive floors or earthed areas, platforms
and working platforms, grounding of door handles, stair handrails, handles
devices, machines and apparatus; providing workers with conductive footwear,
antistatic gowns.
HARMFUL CHEMICALS
A harmful substance is understood as a substance that, upon contact with the body,
causes an occupational injury, occupational disease, or
deviations in health. Classification of hazardous substances and general
safety requirements introduced by GOST 12.1.007-76.
Extent and nature of abnormalities caused by the substance
organism depends on the route of entry into the body, dose, exposure time,
the concentration of the substance, its solubility, the state of the receiving tissue and
the body as a whole, atmospheric pressure, temperature and other
characteristics of the environment.
The effect of harmful substances on the body can be
anatomical damage, permanent or temporary disturbances and
combined consequences. Many highly active harmful substances
cause a disorder of normal physiological activity in the body
without noticeable anatomical damage, effects on the work of the nervous and
cardiovascular systems, general metabolism, etc.
Harmful substances enter the body through the respiratory system, gastrointestinal
the intestinal tract and through the skin. Most likely to penetrate
the body of substances in the form of gas, vapor and dust through the respiratory system (about 95%
all poisoning).
The release of harmful substances into the air is possible when carrying out
technological processes and production of work related to the application,
storage, transportation of chemicals> substances and materials, their production and
manufacturing.
Dust is the most common adverse factor
production environment, multiple technological processes and operations
in industry, transport, agriculture are accompanied by
formation and emission of dust, it can be exposed to large
contingents of workers.
The basis for carrying out measures to combat harmful substances is
hygienic rationing.
Maximum permissible concentration (MPC) of harmful substances in the air
working areas are established by GOST 12.1.005-88.
4.3 Organization of workplaces ?????
4.4 Safety requirements on site
The suggested Safety Instructions cover virtually all activities in a car workshop and include:
IOT for administrative and management personnel;
IOT for accumulator;
IOT for gas welder;
IOT for a car repair mechanic;
IOT for a locksmith for the repair of fuel equipment;
IOT for a locksmith-repairman;
IOT for manual welding electric welder;
IOT for the provision of first aid;
IOT when hanging a car and working under it;
IOT when performing tire repair work;
Introductory briefing log form;
Form of the register of instructions for labor protection.
The instructions have been drawn up and executed in accordance with all the rules and requirements of the regulatory authorities on the basis of the relevant regulatory documentation. On the basis of the same documentation, samples of forms of magazines were made for registering introductory briefing and accounting for labor protection instructions, in which the covers and headers of tables are presented in the form and in sequence, in accordance with the current legislation.
Consider the safety requirements before starting work.
Upon the arrival of auto mechanics at work, they must change into work overalls, consisting of: shoes, overalls, shirts, hats, jackets. You also have personal protective equipment with you: gloves, goggles. The complete set of overalls may vary depending on the types of work performed. Clothes should be buttoned up and tucked in, trousers should be over shoes, sleeves should be buttoned, hair should be tucked under a tight-fitting headdress.
Before work, the worker checks that the tools and devices are in good working order, not worn out and meet safe working conditions:
The wooden handles of the tools must be smoothly processed, there must be no gouges, chips or other defects on their surface, the tool must be correctly fitted and firmly fixed.
Impact tools (chisels, barbs) should not have cracks, burrs, work hardens, the back of their heads should be smooth, not have cracks, burrs and chips.
The ends of hand tools used for insertion into holes during installation (crowbars for assembly, etc.) must not be knocked down.
Pullers must have serviceable legs, screws, rods and stops.
Safety requirements during work
During work, the worker constantly monitor the health of the equipment and do not leave it unattended. When leaving the workplace, the equipment stops and is de-energized.
The work is carried out in the presence and serviceability of fences, interlocks and other devices that ensure labor safety, and with sufficient illumination of the workplace.
Do not touch the moving mechanisms and rotating parts of machines, as well as the live parts of the equipment under voltage, without first de-energizing the dangerous object.
Foreign objects and tools are located at a distance from moving mechanisms.
When starting the machine, unit, machine, the worker must personally make sure that there are no workers in the area of the machine.
In case of unwell, the worker stops working, brings the workplace to a safe state, turns to the chief mechanic, who decides the severity of the consequences and decides to let him go home, continue working some time after taking the medicine, or take him to the hospital. If the chief mechanic is not on site, then a person replacing him must be appointed. Safety requirements in emergency situations. In case of noticed malfunctions of production equipment and tools, as well as if, when touching the machine, machine tool, unit, the effect of an electric current is felt, or there is a strong electrical appliance. , electric motors, electrical equipment, sparking or broken wires, etc., immediately warn workers about the danger, and inform the chief mechanic.
If necessary, the evacuation of people from the danger zone is organized.
In case of accidents with people, each of the workers can provide first aid, because everything you need is in the first-aid kit, while immediately notifying the chief mechanic, and preserves the situation in which the accident occurred, if this does not threaten the life and health of others and does not disrupt the technical process before the arrival of persons, investigation of the causes of the accident.
In case of electric shock, release the victim from the action of the current as soon as possible, since the duration of its action is determined by the severity of the injury. To do this, there is a switch in the workshop for quickly de-energizing the premises.
Safety requirement at the end of work.
At the end of the shift, the workplace is put in order (equipment, tools are cleaned of dust and dirt, garbage and waste are collected and taken out to the designated place, tools, devices and untreated parts are collected and folded into the designated place).
Fences and safety signs are installed at open openings, openings and hatches.
The equipment is de-energized, ventilation and local lighting are turned off.
The worker takes off his overalls and other personal protective equipment, puts them in a closed cabinet, if the overalls require washing or repair, it is necessary to tell the chief mechanic, he will give another one, and the dirty clothes will go to dry cleaning. Personal hygiene rules are followed.
Fire safety
During the first and subsequent briefings, each employee is explained the location of the fire shield, how and how it is necessary to extinguish one or another fire source so that it is safe for the worker himself.
Workers are prohibited from obstructing walkways and access to fire-fighting equipment; this is a strict violation of fire safety rules.
Fuel and lubricants spilled on the ground are covered with sand. Sand soaked in petroleum products must be immediately removed and taken to a place agreed with the sanitary and epidemiological station.
The used cleaning material is removed in a special metal chest with a lid.
It is forbidden to store flammable objects and flammable liquids, acids and alkalis in the workplace in quantities exceeding the replaceable need for a ready-to-use form.
In a car workshop, smoke extractors with a fusible element are used as a fire alarm, which notify about a fire using a siren.
A worker who has violated the requirements of labor protection instructions may be brought to disciplinary liability in accordance with the internal regulations, and if these violations are related to causing material damage to the auto repair shop, the worker is also financially liable in accordance with the established procedure.
During operation, the technical condition of the rolling stock, due to the influence of natural wear and tear, aging, deformation and corrosion of parts, components and assemblies, is constantly changing. Each of these reasons, alone or in combination with others, can cause breakdown or damage - vehicle failure, disrupting its performance and leading to the termination of transport work. The reasons for the manifestation of truck failures, identified through experimental studies, are as follows:
Wear - 40%
Plastic deformation -26%
Fatigue damage -18%
Thermal damage - 12%
Others - 4%
One of the main permanent causes of changes in the technical state of mechanisms is the wear of parts, the intensity of which increases during operation. With an increase in the wear of parts, the likelihood of their loss of performance increases, i.e. with an increase in the vehicle's mileage since the beginning of operation, the probability of its failure increases.
A huge number of variables affect the occurrence of vehicle failure. These include: the quality of the material from which the part is made; precision and cleanliness of parts processing; build quality of cars and units; operating conditions of cars (natural and climatic conditions, quality of highways, traffic intensity, etc.); quality of operating materials; the level of organization of production for maintenance and repair of cars; qualifications of drivers and repair workers, etc.
For example, the use of certain driving techniques changes the rate of wear and the number of car breakdowns by 2 - 3 times. Those. an experienced, highly skilled driver using rational driving practices can provide a wear rate and the number of car breakdowns three times less than that of an unskilled, inexperienced driver.
The processes occurring in technology and nature under the influence of a large number of variable factors, the values of which are unknown, cannot be described by a rigid connection of functional dependence. Probabilistic methods are used to describe and study such random processes. The characteristic of a random variable is probability - a numerical measure of the degree of possibility of the occurrence of the event under study.
The probability of a car failure g (L) for a mileage L is determined based on the processing of statistical information from the test results of a large number of cars:
where: g (L) - the number of cars that failed for mileage L; N is the total number of tested cars.
The probability of failure to occur, or, as it is commonly called, the probability of failure-free operation P (L) is directly related to the probability of failure:
The sum of the probabilities of failure and uptime is a valid event, i.e. one of these events is an accomplished fact:
The likelihood of a car's trouble-free operation is often referred to as a function or law of reliability. A graphical representation of the probability of failure-free operation and the probability of failure are shown in Figure 2.1.
Figure 2.1. The graph of the change in the probability of no-failure operation and the probability of vehicle failure for mileage L.
The most important indicators characterizing the performance of products are the parameter of the failure flow L and failure rate (L). Failure flow parameter i represents the number of failures per product per unit run:
where m i(L) - the number of failures of each of the N products for the run L;
N is the total number of products;
L - run interval.
Failure rate (risk of failure) (L) is a function that characterizes the change in the number of failures per one workable product per unit run:
where n (L) is the number of products that have lost their performance during the run L.
Numerous experimental studies show that the dependence of the failure rate on the mileage has a characteristic form (Figure 2.2).
Rice. 2.2. The graph of the change in the failure rate depending on the mileage.
The curve of change in the failure rate during operation has three distinct periods characterizing the technical condition of the rolling stock.
The first period (running-in period) is characterized by an increase in the parameter of the flow of failures and the failure rate due to the "running-in" of parts of assemblies and assemblies. The running-in period takes a small interval compared to the total service life of vehicles. Preventive actions during this period are carried out according to the instructions of the manufacturers.
In the second period (steady state period), the most stable technical condition of the rolling stock is observed with a slight increase in the failure rate.
The third period (the "aging" period) is characterized by a sharp increase in the failure rate. Along with wear, the influence of fatigue stresses increases on the manifestation of failures during this period. Due to a sharp increase in the risk of failures, in the third period, the operation of the car becomes economically unprofitable, it has to be removed from service and sent for major (refurbishment) repairs or written off.
Thus, the main period in terms of the duration of the car's operation, which interests us, is the period of the steady-state wear rate of parts of assemblies and assemblies, when the failure rate (L) is practically constant:
(L) const
The regularity of the appearance of sudden failures with a relatively constant value of the danger of failures, in the theory of reliability, is described using an exponential law. For an exponential law, the probability of failure g (L) for the run L will be equal to:
where: - the average number of refusals per unit run.
A car is a complex technical system consisting of a very large number of elements (parts), each of which has a relatively high reliability. Rare flows of failures of individual elements, when considered as a whole for a car or a fleet of cars, form a stable flow of failures with a characteristic that differs from the flow of failures of individual elements. Such failure flows in probability theory are called Poisson, and for (L) const- stationary Poisson or simplest.
The probability of failure g k (L) "k" of cars for the mileage L for the simplest flow of failures is described by the expression:
To simplify calculations, with a fairly high reliability, this expression can be replaced by a linear relationship:
Based on this dependence, given the indicators of the admissible probability of failures for the car park and the average number of failures per unit run, it is possible to determine the frequency of maintenance L that will provide the necessary (specified) level of reliability of the car
L TO = 
;
During operation, the performance characteristics of the rolling stock are constantly changing. The degree of increase in the parameter of the flow of failures, the rate of failures and other parameters characterizing the technical condition of the rolling stock depends both on the design features of the vehicle and its operating conditions, and on the system of measures to maintain the rolling stock in a working condition.
Car maintenance and repair system
The system of maintenance and repair, using the given regularities of changes in the technical condition and reliability parameters, should organize the technical operation of vehicles so that the required level of reliability of their work is ensured.
Maintenance of the rolling stock in a working condition and ensuring the required level of reliability of their work is carried out by carrying out preventive actions (technical maintenance) and performing repair work.
Maintenance serves the purpose of maintaining the operability of the rolling stock with preventive measures that reduce the wear rate of parts, components and assemblies of the vehicle and prevent the occurrence of their failures in the period between regular services. The purpose of the repair is to restore the lost operability of the rolling stock by eliminating the failures that have arisen.
Preventive and repair actions provide for the same goal - to ensure the transportation of goods and passengers with a technically sound rolling stock. The efficiency of the maintenance and repair system depends on the organization of work and the rational interaction of all its divisions that perform various functions, but are interconnected by a common goal - to maintain the rolling stock in a technically sound condition at minimal cost. At the same time, the level of operability of the rolling stock significantly depends on the correct choice of prevention modes - the frequency and depth (labor intensity) of preventive actions.
The random nature of the change in the technical condition of the rolling stock makes it necessary to carry out preventive actions for each individual vehicle, not with a constant predetermined nomenclature and volume of work, but in accordance with the revealed actual
need. The organization of the operation of the maintenance and repair system without taking into account the randomness of events, as a rule, is the cause of private and long-term downtime of rolling stock in current repairs and their high cost. Studies show that up to 90% of labor and material costs allocated for maintenance and repair are directed to work in the current repair area.
The system of maintenance and repair of rolling stock is a complex system that represents the integration of a number of production units that are closely related to each other. The work of the entire complex system as a whole depends on the work of each of them. To ensure the maximum effect from the joint work of the subdivisions of the TO and TR system, it is necessary, first of all, to determine the most rational methods and principles of organizing production in these subdivisions and the strategy of the operation of the TO and TR system. In our case, a strategy is understood as a certain action plan and the corresponding principle of organizing technical impacts to rolling stock under various operating conditions.
There are three main strategies for preventive and repair work. Let's call them A, B, C:
■ Strategy "A" - performing work on the occurrence of failures (random);
■ Strategy "B" - execution of works in a planned manner (planned);
■ Strategy "C" - includes strategy elements A and B (mixed).
Strategy "A" provides for the implementation of both repair and preventive actions as needed at a random, not planned in advance time. Clarification of the scope of technical interventions to eliminate self-manifested failures and quality control of work performance can be carried out when diagnosing a car.
Performing technical actions according to a random strategy is preferable for cars during the period of their intensive wear (the third period of operation). During this period, the implementation of scheduled preventive work on vehicles does not provide a sufficient level of probability of their failure-free
work between planned impacts due to the impossibility of routinely changing the increasing frequency of technical impacts at a time when the regularities of changes in reliability characteristics are unreliable and are practically not studied.
Strategy "B" presupposes the implementation of all necessary preventive and repair work during the planned introduction of the vehicle into the system. The work required by the car to ensure a sufficient level of its trouble-free operation between planned installations in the system is established by the entire monitoring and diagnostic system. The frequency of planned impacts (vehicle insertion into the system) L pl is determined by the required level of probability of failure-free operation of the vehicle P (L):
Taking into account the resolution of the diagnostics P d, the frequency of planned actions will be equal to:
Strategy "B" is advisable during the period of the steady state operation of the vehicle (second period). However, it can also be used to keep the vehicle in good working order and in the initial period of their operation.
Strategy "C" (mixed) has elements of both of the strategies we have considered. A mixed strategy is at the heart of building the existing preventive maintenance system and car repairs. The organization of work on this strategy is in accordance with the recommendations set out in the "Regulations on maintenance and repair of rolling stock of road transport ".
The ratio of the volume of preventive and repair work carried out with the strategy "C" depends on the quality of manufacture, design and technology.
the technical state of the rolling stock, the organization of the technological process and the state of the production base, the operating conditions, the established frequency and volumes of service.
The choice of the strategy of technical impacts has a significant impact on the cost and efficiency of the system for maintaining the rolling stock in a technically sound condition. The wrong choice of strategy can be accompanied, on the one hand, by large downtime and the amount of work to eliminate failures (strategy on demand), and, on the other hand, by an excessively large amount of prevention of cars and their units (planned strategy with insufficiently developed diagnostics). When choosing the most profitable strategy of technical impacts, both economic and technical criteria are used.
As a technical criterion, the technical readiness factor t can be used, which is one of the most generalizing characteristics of maintaining a rolling stock in a working condition. The highest technical readiness factor is provided with the planned strategy "B" of performing technical actions (Fig. 2.3.), Which is the most preferable from the point of view of ensuring a higher level of rolling stock operability.
Rice. 2.3. The graph of the change in the coefficient of technical readiness during operation with different strategies.
From an economic point of view, the preferable strategy will probably be the one that will ensure the minimum cost of maintaining the rolling stock in working order. As studies have shown (Fig. 2.4.) And according to economic criteria during the running-in period and normal operation of the rolling stock, the most preferable is also a planned strategy for performing impacts.
Rice. 2.4. The schedule of changes in the costs of maintenance and repair of cars during their operation with different strategies.
According to the above, of all the specified strategies for technical interventions, the planned strategy "B" is more effective. However, it should be borne in mind that the planning strategy provides for a large amount of diagnostic work, identification and elimination of malfunctions in the process of carrying out preventive work, which is not always possible to ensure in practice due to the low resolution of diagnostics or the lack of the necessary diagnostic equipment. Therefore, in the production of maintenance and repair of cars, a planned strategy is used to perform routine maintenance, and a random strategy is used to eliminate self-manifested and identified breakdowns and malfunctions.
Taking into account the foregoing, in world practice, a planned preventive system for performing technical actions is used to maintain vehicles in a working condition. This system consists in the planned (preventive) implementation routine maintenance for maintenance and repairs as needed. The choice of modes of planned technical interventions is of great importance for ensuring a given level of reliability of the operation of vehicles and reducing the cost of their maintenance and repair. There are various methods of establishing rational modes of maintenance: technical and economic; economics - probabilistic; probabilistic, etc.
The technical and economic method consists in determining the frequency of maintenance L opt according to the minimum unit total costs 
for maintenance and repair of cars per unit of mileage (Figure 2.5).
Rice. 2.5. Technical and economic method for determining the frequency of maintenance.
Due to the different operating modes of cars, their units and parts, the need for their repair also arises through different runs.
Parts, assemblies, units with different reliability indicators require different periodicity of maintenance and repair (Fig.2.6.). However, given that it is almost impossible to install and perform maintenance of all units, assemblies and parts separately at different intervals, they are carried out at average intervals.
Rice. 2.6. Reliability indicators of various groups (1,2,3) parts.
To solve the problems of ensuring a predetermined level of reliability of the operation of vehicles, the method of determining the frequency of maintenance by the maximum permissible value of the level of the technical condition of the rolling stock is of interest (Fig. 2.7.). It consists in determining the frequency of maintenance according to the maximum permissible level of the parameter of the technical condition of the rolling stock based on the regularity of its change in mileage. The maximum permissible level of technical condition is set for each unit or group of parts, depending on the nature of their work, operating conditions, type of transportation, etc.
Rice. 2.7. Determination of the frequency of maintenance of parts (assemblies) of various groups (1,2) according to the level of probability of failure-free operation.
With this method of determining the frequency of impacts, it becomes possible to manage the reliability of the fleet of vehicles, which consists in setting the intervals for performing maintenance that provide a given level of reliability (probability of failure-free operation) of various groups of parts and assemblies.
According to the existing regulations on MOT and TR, the car is scheduled (according to mileage or calendar dates) for the next maintenance, in which a pre-planned amount of routine maintenance is performed in specialized areas. The list of works associated with the maintenance of repair and some routine maintenance is specified when diagnosing the car.
Diagnostics reveals car failures and malfunctions and determines the scope of work to eliminate them. The identified failures and malfunctions are eliminated in the main production using units and assemblies repaired in the workshops of the auxiliary production.
At the current level of development, diagnostics cannot yet establish the technical state of all individual joints of units and parts of a car, the testability of which ranges from 0.5 to 0.74. As a result, 25 - 50% of all work on vehicle maintenance has to be regulated by the implementation of the appropriate nomenclature of work. Diagnostics can detect failures of individual systems and nodes with a probability (reliability) of 0.8 - 0.85. According to the studies carried out, up to 40% of all malfunctions are spontaneous failures, which are eliminated in the current repair area.
In the future, with the development of the design of automobiles and diagnostic tools, it is planned to increase the overall controllability of vehicle components and assemblies and the resolution of diagnostics, which will help to reduce the amount of work of accidental influences and increase the likelihood of trouble-free operation of the rolling stock.
Organizational structures and methods of operation of the maintenance and repair system
The interconnected and orderly work of individual subdivisions of the system is the essence of the organization of the system as a whole. Therefore, for the analysis of the operation of the TO and TR system, the organizational structure is of particular interest. The organizational structure of the system should be understood as the established division of labor between people, their grouping in the system and its subdivisions, which determine the sequence and priority of work.
The organizational structure of the system of maintenance and repair of cars depends on the principle of work, in accordance with which the technology of the production process is built. The production principle can be of two types: technological and substantive. In the first case, production is based on technological operations (EO, TO-1, TO-2, TP), in the second - a car (unit) and its ability to trouble-free transport operation.
Rice. 2.8. Organizational structures of the system of maintenance and repair of cars in the ATP.
The choice of a production structure with a rational, technologically sound distribution of work across workshops, sections and workplaces, taking into account specific conditions and technological links between all subsystems and their elements, is the basis for making many decisions of an organizational nature. The production structure of the TO and TR system must correspond to the adopted strategy and the organization of its work.
In ATP, three types of production structures are used: technological, subject, mixed (subject-technological) (Fig. 2.8).
The work of the main production with the technological structure is built according to the method of specialized teams. Each team is specialized in
performing only one of the types of technical interventions (EO, TO-1, TO-2, TP), which ensures the technological uniformity of each section, increases the productivity of work due to specialization.
With the existing scheduled preventive maintenance and repair system, the technological structure has become widespread in the organization of work in the main production. However, due to the violation of the system principle of the relationship between various types of technical influences, the management of the entire system as a whole becomes more complicated, since the end result of the labor of disparate groups of workers is not a car, but only a certain technical impact. This makes it difficult to control the quality of work performed and remuneration for the final result. The most significant drawback of this type of structure is the low quality of work on the maintenance and repair of cars, which leads to an increase in random failures, an increase in downtime in repairs and a decrease in the technical availability factor of the vehicle fleet.
The subject structure of production can be built on subject automotive or subject aggregate principles.
With the aggregate (aggregate-divisional) structure, specialized integrated teams are created to perform a set of works (TO-1, TO-2, TR) for individual groups of units and mechanisms assigned to this team. The aggregate structure makes it possible to increase the productivity of individual workers in comparison with the technological structure due to the specialization and mechanization of work, the responsibility for the quality of work performed for a group of aggregates for the entire fleet of vehicles is specified. But it should be borne in mind that with such a structure, the system principle of maintenance and repair is also violated, i.e. as the end result of labor, individual units are considered, and not the car as a whole.
As practice has shown work of ATU, the use of the aggregate structure is most appropriate when organizing the work of auxiliary production.
The subject automobile structure differs from the aggregate structure in that the object of labor of repair workers is not a group of aggregates, but a car as a whole. With such a structure, service is carried out according to the need, determined by diagnostics, by one complex brigade for one setting of the car into the system. This simplifies the accounting of the assessment of the quality of work performed by the brigade in terms of the amount of non-failure operation of vehicles on the line. The disadvantages of this structure include some organizational difficulties in the distribution of spare parts, garage equipment and production areas by teams and the universalization of repair workers is required.
Considering that the substantive automotive organizational structure of the maintenance and repair system contributes to an increase in the responsibility of repair workers for the technical condition of the rolling stock and the improvement of the quality of maintenance and repair, it seems appropriate to use it in organizing work in the main production. The disadvantages inherent in this structure can be reduced due to the appropriate organization of the work of complex teams and various management influences. So, by assigning repair teams to a group (column) of cars and the simultaneous performance of maintenance and repair work in one vehicle installation into the system, it is possible to achieve a high quality of work and a significant increase in the parameters of the reliability of vehicles in operation.
The mixed subject-technological structure of the organization of work has the advantages and disadvantages of the above subject and technological structures. A mixed structure is used in some ATP to organize the work of the main and auxiliary production. For example, according to the technological principle, work can be carried out according to EO and TO-1, and according to the subject principle - TO-2 and TR. The structure can also be classified as mixed, when units are repaired according to the subject principle, and cars are serviced and repaired according to the technological principle. Each of the considered structures has its own specifics, its own method
organization of production, has certain advantages and disadvantages. Each of them is characterized by its own organization of workplaces.
The organization of workplaces differs primarily in the type of production posts for performing basic operations and individual, elements of the technological process, which determines the number of stages and the sequence of performing operations of technical actions. Car service and repair can be organized at specialized posts, production lines or universal posts.
Specialized posts are used to perform certain types of maintenance and repair. So, in the main production at specialized posts, some nomenclature works (lubrication, fastening, etc.) can be carried out, in auxiliary production they can be used to organize work on individual components and assemblies (maintenance and repair of the engine, electrical equipment, etc.). Diagnostic work is also carried out, as a rule, at specialized posts.
A further development of the method of specialized posts was the flow method of organizing work. With the in-line method of performing actions at each post, it is necessary to perform work in a strictly established order for a limited time in accordance with the cycle of the line. However, as we indicated earlier, the volume of one or another impact to the rolling stock is a random variable that depends on numerous factors and has a large dispersion from its mathematical expectation. As a result, asynchrony occurs in the work of posts, which in a number of cases leads to losses of working time, downtime of equipment and rolling stock.
With a planned strategy of putting rolling stock into the system, the most expedient is the use of the subject organization of work (automotive in the main production and aggregate in the auxiliary). In this case, work in the subsystems of diagnostics and auxiliary production, as a rule, is carried out at specialized posts, and mainly in production at universal posts.
The principles of work organization and production technology, taking into account the characteristics of the enterprise and operating conditions, must be worked out in detail and provided for in the process of technological design.
