The breakdown of any car is a very unpleasant event, in most cases entailing considerable costs. What can we say about the breakdown of trucks, vehicles that are designed to transport goods daily around the city, country and beyond, and problems with which can significantly slow down or even completely stop production and trade processes, because trucks transport equipment, machinery, furniture, building materials, food, industrial goods. Of course, in order to prevent unexpected breakdown and failure of equipment, it is necessary to monitor it and periodically send it for qualified diagnostics using specialized equipment. Depending on the type and manufacturer, regular inspection and repair trucks must be carried out every 20-120 thousand kilometers.
And diagnostics prolong the service life of not only the machine as a whole, but also each individual part or assembly. Checks carried out on time can prevent the inevitable replacement of components, parts or mechanisms of a truck in other cases.
Usually the reasons for which it is necessary to carry out repair work become various damage cars due to an accident, a malfunction in the operation of the gearbox, wear of parts, unstable operation of the chassis, and so on.
Due to the nature of trucks, repairing such vehicles is not an easy task. Dimensions require enough space and powerful equipment, and features and specific technical requirements to models of various manufacturers - a certain amount of knowledge and qualifications. After all, the cost of special equipment and trucks usually significantly exceeds the cost of passenger cars, and their design and construction are much more complicated. In addition, all kinds of modular designs and often rare truck parts lead to a long search for spare parts, because if the service you decide to contact does not specialize in the repair of trucks, it is unlikely that it will be able to quickly find original spare parts at the right price. Also, taking into account the peculiarities of assembling "workhorses" from different manufacturers, very often for the repair of an engine, chassis, gearbox and other mechanisms, it is necessary to have special modern technological equipment.
Depending on the scope of work, truck repairs can be of three types: scheduled inspection, minor repairs and overhaul. In this case, the inspection includes the diagnosis and verification of the operation of the mechanisms. Minor repairs include such work as body repair (painting and removal of body deformations), the change of some parts or assemblies. But during the overhaul truck completely disassembled, the electrical wiring changes, the gearbox, engine, chassis and other vital parts of the machine are overhauled.
Due to the fact that trucks regularly overcome hundreds of kilometers of not the smoothest roads, while working in rather harsh climatic conditions, truck repair services in our country are quite in demand. And demand creates supply - and now, dozens of companies offer to repair your car. But remember, when choosing a service, it is very important not to miscalculate and get to specialists who guarantee well-tightened nuts, correctly installed mechanisms, well-coordinated and accurate operation of components and mechanisms, and, of course, the overall quality result.
Technology and organization of work of maintenance and repair of trucks
The basis for the organization of work at the ATP is the Regulation on maintenance and repair cars. This provision is mandatory for all ATPs that perform maintenance and repair of these vehicles.
Vehicle maintenance is a complex of works aimed at preventing failures and malfunctions, maintaining vehicles in good condition and ensuring their reliable, safe and environmentally friendly operation. Maintenance includes the following types of work: control and diagnostic, fixing, adjustment, electrical, work on the power system, refueling, lubrication and others.
According to the frequency, list and labor intensity of the work on maintenance of trucks, they are divided into the following types: daily maintenance (EO); periodic maintenance (TO), seasonal service(CO).
SW includes MMR, refueling and controls aimed at ensuring daily safety and maintaining proper appearance car.
Maintenance involves the performance of a certain amount of work through the established operational mileage of the car. In accordance with the standards for maintenance of trucks according to the frequency of SW once a day, TO-1 after 4000 km, TO-2 after 16000 km of run.
SO provides for the performance of maintenance and additional operations to prepare the car for winter or summer operation in accordance with the recommendations of manufacturers.
Repair is a set of works to eliminate the malfunctions that have arisen and restore the working capacity of the car as a whole or the unit. Car repair is carried out as needed and includes control and diagnostic, disassembly and assembly, locksmith, mechanical, fuel and economic, electrical work. For high-quality performance of MOT and TR, the STO is equipped with the necessary posts, devices, devices, fixtures, tools and equipment, technical documentation.
The main part of the work on maintenance and repair is carried out at the posts and auxiliary posts of the production building in the area of maintenance and repair of vehicles. In addition, work on the maintenance and repair of power supply system devices and electrical equipment is carried out at specialized sites. Battery works are carried out at the electrical site and partly for the repair of equipment.
Analysis of literary sources on maintenance and repair
When servicing vehicles at the ATP, special attention is paid to malfunctions that may affect traffic safety. At the same time, the identified malfunctions and loosening of the fastening of the following parts, assemblies, assemblies and systems must be eliminated:
when adjusting linings of shoes and brake drums, brake pedal, parking brake system, steering, wheel bearings;
during control, diagnostic and fixing work of the bipod and pendulum steering lever, steering gear, steering rods on ball pins and ball pins in sockets, ball bearings, pivots, knuckle, wheel disks, driveline or actuators, springs and springs, shock absorbers, suspension arms, pipelines, hydraulic brake hoses, main brake actuator, brake pressure regulator, engine, separator, windows, windshield washer, wiper, rear-view mirrors, windshield blower and heater, ventilation and heating systems;
when servicing power systems and electrical equipment of the power supply system and exhaust gases, headlights, front and rear lights, light switches, retroreflectors, horn, electrical wiring, alarm, brake signal.
TO-1 is carried out at the intervals indicated above, but at least 2 times a year to perform the following work:
control and diagnostic - checking the operation of the service brake system for simultaneous operation and braking efficiency, the operation of the parking brake system, the brake actuator, checking the connections in the steering gear, the condition of the tires, lighting and signaling devices;
inspection - inspection and check of the body, glass, license plates, the operation of door mechanisms, wipers, checking rear-view mirrors, checking the tightness of the connections of lubrication, cooling and hydraulic drive clutch engagement, rubber protective covers on drives and steering rod joints, clutch and brake pedal free play, fan belt tension, levels brake fluid in the tanks of the main brake cylinder and a drive for disengaging the clutch, springs and a lever in the front suspension, rods and struts of the anti-roll bar;
fastening - fastening the engine to the body, gearbox and extension, steering gear housing and steering arm, steering wheel and steering rods, swing arms, connecting flanges cardan shaft, wheel disks, instruments, pipelines and hoses of the lubrication system and cooling system, brake mechanisms and hydraulic clutch release, exhaust pipe of the muffler;
adjusting - adjustment of the free play of the clutch and brake pedal, the action of the working and parking brake systems, steering wheel free play and clearance in the steering gear connections, fan and alternator belt tension; bringing to the norm the air pressure in the tires and the brake fluid levels in the nutrient tanks of the main brake cylinder and the clutch release drive.
At TO-1, they also clean it of dirt and check the devices of the power system and the tightness of their connections; check the operation of the drive, the completeness of closing and opening the throttle and air dampers, regulate the operation of the carburetor at low speed modes crankshaft engine. In the electrical system, the battery and its ventilation holes are cleaned of dirt; check the fastening, the reliability of the contact of the wire tips with the terminals and the electrolyte level in each of the battery cans; clean electrical equipment from dust and dirt; check the insulation of electrical equipment, the fastening of the generator, starter and relay-regulator, check the fastening of the starter, ignition coils.
TO-2 is recommended to be carried out at the intervals indicated above, but at least once a year. Before performing TO-2 or in the process of it, it is advisable to carry out in-depth diagnostics of all the main units, components and systems of the vehicle to establish them. technical condition, determining the nature of malfunctions, their causes, as well as the possibility of further operation of this unit, unit and system.
This establishes the following:
engine - the presence of knocks in the connecting rod bearings and the gas distribution mechanism, valves, gear wheels ah, developed power, malfunction of the ignition system as a whole and its individual elements;
engine power system
fuel leakage in pipeline connections, in the planes of the connector, increased consumption fuel and CO content in exhaust gases for passing a technical inspection at the State traffic inspectorate, the condition of parts of the cylinder-piston group, gas distribution systems, cylinder head gaskets;
engine lubrication system - oil leakage at the joints and connectors (crankshaft oil seals, engine crankcase, timing cover, and others), pressure in the lubrication system and correct readings of instruments installed on the vehicle;
engine cooling system - leakage of coolant in the joints and connectors, system nodes (radiator, water pump, etc.), overheating of the coolant when the engine is running under load;
clutch - slipping under load, jerking during gear shifting, the presence of knocks and noises during operation and gear shifting, malfunction of the clutch drive;
gearbox - the presence of knocks and noises in working condition, spontaneous shutdown under load, the presence of oil leaks at the points of separation of gearbox parts, the size of the gap when shifting gears;
rear axle - the presence of knocks and noises in working condition, the presence of oil leaks at the points of separation of parts rear axle, the value of the total clearance in the main gear and differential;
cardan shaft and intermediate support - gaps in cardan joints, splined joints and in the intermediate support of the cardan shaft;
steering - the force required to rotate the steering wheel, the clearance of the steering arm shaft in the bushings, the reliability of fastening of the springs and front suspension arms, as well as the bars and struts of the anti-roll bar;
springs and suspension elements - the presence of breakages of sheets or springs, gaps in the joints of the spring pin with the spring bushing and with the eye of the suspension brackets, the parallelism of the front and rear axles and their location relative to the car body;
body elements - the presence of dents, cracks, breakdowns, a violation of the car's color, the correct operation of the windshield washer, the body heating system and the windshield blower, the condition of the locks and hinges of the hood, trunk lid and doors.
fixing the radiator, cylinder head and rocker arms, covers of the casing of the cylinder head, intake and exhaust pipelines, cover of the block of timing gears, housings of oil filters, engine oil pan, clutch housing, shock absorbers, fuel tank, muffler, rear axle gear cover, ladder, spring pins, locks and door handles;
In the power system, the tightness of the fuel tank and pipeline connections, the fastening of the carburetor are checked and the identified malfunctions are eliminated. Remove the carburetor and fuel pump, disassemble them, clean them and check the condition of the parts on special devices. After assembly, the fuel pump is checked on a special device.
They check the correct operation of the windshield washer, the body heating system and the windshield blower, the condition of the locks and hinges of the hood, trunk lid and doors.
In addition, it is necessary to check and adjust the angles of the steered wheels, the effectiveness of the operation and simultaneous operation of the brake mechanisms, wheel balancing, the operation of the car's ignition system, the gap between the breaker contacts, the installation and operation of the headlights, the direction of the light flux, the condition of the entire brake actuator, the condition of the radiator, rubber cushions, engine mounts.
With TO-2, in addition to the scope of work for TO-1, a number of additional operations are performed:
fixing the radiator, cylinder head and rocker arms, covers of the casing of the cylinder head, intake and exhaust pipelines, cover of the block of distribution gears, oil filter housings, engine oil pan, clutch housing, shock absorbers, fuel tank, muffler, rear axle gear cover, ladder, spring fingers, locks and door handles;
tightening the nuts for fastening the flange to the drive gear of the final drive of the rear axle and the hinge pins for fastening the shock absorber lugs;
adjustment of the effort of turning the steering wheel, thermal clearances of valves, tension of the drive chain of the engine gas distribution mechanism, the gap between the brake pads and wheel disks, the gap in the bearings of the front wheel hubs.
In the power system, the tightness of the fuel tank and pipeline connections, the fastening of the carburetor are checked and the identified malfunctions are eliminated. Remove the carburetor and fuel pump, disassemble them,
clean and check the condition of parts on special devices. After assembly, the fuel pump is checked on a special device. The ease of starting and operation of the engine are also checked.
When servicing the electrical system, the following is done: remove the battery from the car and check the degree of charge, check the condition of the brushes and collectors of the generator and starter, the operation of the relay-regulator; adjust the tension of the anchor springs; remove the spark plugs and check their condition, clean them from soot and adjust the gaps between the electrodes; remove the ignition breaker-distributor and clean its outer surface of dirt and oil, check the condition of the contacts and adjust the gaps between them, lubricate the breaker-distributor shaft; check the condition of low and high voltage wires and regulate the operation of lighting and signaling devices.
TO-1, TO-2 and CO are carried out in the TO and TR area at dead-end posts equipped with lifts.
During TR, disassembly and assembly operations, electrical, metalwork and mechanical are performed.
Dismantling and assembly work includes the removal of individual panels or parts of the body, mechanisms, glass and other removable parts. Partial disassembly of the body for the repair of its parts is carried out to the extent necessary to ensure the quality of all repair operations. For the assembly of bodies after repair, including the installation of components and parts on the body, various devices and tool kits are used.
The electrical workshop is designed to service electrical equipment of the car, the malfunction of which cannot be eliminated during maintenance directly on the car, as well as to service carburetors, fuel pumps, sedimentation tanks, fuel and air filters, fuel lines and other devices of the vehicle power system, removed from them at the maintenance and TR posts.
Fuel equipment that requires an in-depth check, adjustment or repair comes to the workshop and from the diagnostic post. Devices, parts and components of the power system that arrived at the site are cleaned of contamination, checked and repaired using specialized equipment. After that, the repaired carburetor, fuel pump and other parts are tested on specialized stands. After testing, all devices and parts of the power system are installed on the car.
Then, a final check of the quality of the repair and adjustment of the carburetor on a dynamometer stand are carried out to achieve minimal exhaust toxicity and maximum efficiency.
In the case of electrical equipment TS, devices and assemblies are disassembled into separate components and parts, control and detection of defects in assemblies and parts, replacement of small unusable parts, stripping and turning of the collector, restoration of damage to the insulation of connecting wires and coil leads, soldering of wire lugs, assembly of the device and assembly, testing on a specialized stand.
Justification of the graduation project
Based on the analysis of production activities and literary sources, the enterprise has reserves for improving the technology of maintenance and repair.
Based on the regulatory requirements for maintenance and repair, as well as the state of the organization of work for their implementation, it is necessary to solve the following tasks:
Calculate the production program;
Calculate the annual volume of work;
Determine the number of posts (working and auxiliary, car waiting and storage places);
Determine the number of workers at the station;
Choose methods for organizing maintenance and repair;
Select a list of necessary technological equipment;
Determine the area of industrial warehouse, auxiliary premises;
Consider issues, the state of labor protection at work; propose organizational and technological measures aimed at reducing and preventing accidents. Calculate lighting and ventilation. Consider the environmental safety of the project;
Assess the technical and economic efficiency of the ATP project.
During operation, the technical condition of the rolling stock, due to the influence of natural wear, aging, deformation and corrosion of parts, assemblies and assemblies, is continuously changing. Each of these reasons, individually or in combination with others, can cause breakdown or damage - the failure of the car, disrupting its performance and leading to the cessation of transport work. The reasons for the manifestation of truck failures, identified through experimental studies, are as follows:
Depreciation - 40%
Plastic deformation -26%
Fatigue failure -18%
Thermal destruction - 12%
Others - 4%
One of the main permanent causes of changes in the technical condition 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 mileage of the car from the beginning of operation, the probability of its failure increases.
A huge number of variable factors influence the occurrence of a car failure. These include: the quality of the material from which the part is made; accuracy and cleanliness of parts processing; assembly quality of cars and units; operating conditions of vehicles (natural and climatic conditions, quality highways, traffic intensity, etc.); quality of operating materials; the level of organization of production for maintenance and repair of vehicles; qualifications of drivers and maintenance workers, etc.
So, 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 techniques can achieve a rate of wear and tear of a car that is 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. A 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 vehicle failure g(L) for a mileage L is determined based on the processing of statistical information from the results of testing a large number of vehicles:
where: g(L) - the number of cars that failed for the run L; N - the total number of cars tested.
The probability of non-failure 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 reliable event, i.e. one of these events is a fait accompli:
The probability of failure-free operation of a car is often called 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.
Fig.2.1. Graph of the change in the probability of no-failure operation and the probability of failure of the car for the mileage L.
The most important indicators characterizing the performance of products are the failure rate parameter L and failure rate(L). Bounce 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 run L;
N is the total number of products;
L - run interval.
Failure rate (failure hazard) (L) is a function that characterizes the change in the number of failures per one operable product per unit run:
where n (L) is the number of products that have lost their functionality during the run L.
Numerous experimental studies show that the dependence of the failure rate on the run has a characteristic form (Fig. 2.2).
Rice. 2.2. Graph of the change in the failure rate depending on the mileage.
The curve of change in the intensity of failures during operation has three pronounced periods characterizing the technical condition of the rolling stock.
The first period (run-in period) is characterized by an increase in the failure rate parameter and failure rate due to the "run-in" of parts of units and assemblies. The running-in period takes a small interval compared to the total life of the vehicles. Preventive actions during this period are carried out according to the instructions of manufacturers.
In the second period (the 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 a major (recovery) repair or written off.
Thus, the main period for the duration of the operation of the car, which interests us, is the period of the steady wear rate of parts of components 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 the exponential law, the probability of failure g(L) for the run L will be equal to:
where: - average number of failures 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 failure flows of individual elements, when considered as a whole for a car or fleet of vehicles, form a stable failure flow with a characteristic different from the failure flow of individual elements. Such failure flows in probability theory are called Poisson, and when (L) const- stationary Poisson or simple.
The probability of failure g k (L) "k" of cars per run L for the simplest failure flow is described by the expression:
To simplify the calculations, with a fairly high reliability, this expression can be replaced by a linear relationship:
Based on this dependence, given the indicators of the permissible failure probability for the car fleet and the average number of failures per unit run, it is possible to determine the frequency of maintenance L, which will provide the necessary (given) 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 failure rate parameter, failure rate 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 working condition.
System Maintenance and car repair
The maintenance and repair system, using the given patterns of changes in the technical condition and reliability parameters, should organize the technical operation of vehicles in such a way as to ensure the required level of reliability of their operation.
Maintenance of the rolling stock in working condition and ensuring the required level of reliability of their work is carried out by carrying out preventive actions (maintenance) and performing repair work.
Maintenance serves the purpose of maintaining the operability of the rolling stock by preventive measures that reduce the wear rate of parts, assemblies and assemblies of the vehicle and prevent the appearance of their failures in the period between regular maintenance. The purpose of the repair is to restore the lost performance of the rolling stock by eliminating the failures that have occurred.
Preventive and repair impacts provide for the same goal - ensuring the transportation of goods and passengers by 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 departments that perform various functions, but are interconnected by a single goal - maintaining the rolling stock in a technically sound condition at minimal cost. At the same time, the level of working capacity 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 necessitates the implementation of preventive measures for each individual vehicle, not with a constant pre-specified nomenclature and scope of work, but in accordance with the identified 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 frequent and long downtime of the rolling stock in the current repair and their high cost. Studies show that up to 90% of the labor and material costs allocated for maintenance and repair are aimed at performing work in the current repair area.
The maintenance and repair system for rolling stock is a complex system representing 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 departments of the TO and TR system, it is necessary, first of all, to determine the most rational methods and principles for organizing production in these departments and the strategy for the operation of the TO and TR system. In our case, the strategy is understood as a certain plan of action and the corresponding principle of organizing technical impacts on rolling stock under various conditions of its operation.
There are three main strategies for preventive and corrective actions. Let's call them A, B, C:
■ Strategy "A" - performance of work on the occurrence of failures (random);
■ Strategy "B" - performance of work in a planned manner (scheduled);
■ Strategy "C" - includes elements of strategy A and B (mixed).
Strategy "A" provides for the implementation of both repair and preventive actions as needed at a random, not pre-planned time. Clarification of the scope of technical actions to eliminate self-manifested failures and quality control of work can be carried out when diagnosing a car.
The implementation of technical actions according to a random strategy is preferable for cars during their intensive wear (the third period of operation). In this period, the implementation of scheduled preventive maintenance on vehicles does not provide a sufficient level of probability of their failure-free operation.
work between planned impacts due to the impossibility to change the increasing frequency of technical impacts in a planned manner at a time when the patterns of changes in reliability characteristics are unreliable and practically not studied.
Strategy "B" involves the implementation of all necessary preventive and repair work during the planned installation of the car into the system. The work necessary for the car to ensure a sufficient level of its trouble-free operation between scheduled installations in the system is established by the entire monitoring and diagnostic system. The frequency of planned actions (setting the car into the system) L pl is determined by the required level of probability of the car's failure-free operation P (L):
Taking into account the diagnostic resolution P d , the frequency of planned actions will be equal to:
Strategy "B" is expedient during the period of the established mode of operation of the car (the second period). However, it can also be used to keep the car in working condition and in the initial period of their operation.
Strategy "C" (mixed) has elements of both of the strategies we have considered. A mixed strategy underlies the construction of the existing preventive maintenance and repair system for vehicles. The organization of work under this strategy complies with the recommendations set out in the "Regulations on the maintenance and repair of rolling stock of road transport."
The ratio of the volumes of preventive and repair work performed under the "C" strategy depends on the quality of manufacturing, design and technical
the technical condition of the rolling stock, the organization of the technological process and the state of the production base, operating conditions, the established frequency and volume of maintenance.
The choice of strategy for technical impacts has a significant impact on the amount of costs and the efficiency of the system to maintain the rolling stock in a technically sound condition. The wrong choice of strategy can be accompanied, on the one hand, by large downtimes and volumes of work to eliminate failures (strategy on demand), and on the other hand, by an excessively large amount of preventive maintenance of vehicles and their units (planned strategy with insufficiently developed diagnostics). When choosing the most profitable strategy of technical actions, both economic and technical criteria are used.
As a technical criterion, the coefficient of technical readiness t, which is one of the most generalizing characteristics of maintaining the rolling stock in working order, can be used. The highest coefficient of technical readiness is provided with the planned strategy "B" for performing technical actions (Fig. 2.3.), which is the most preferable in terms of ensuring a higher level of rolling stock performance.
Rice. 2.3. Graph of change in the coefficient of technical readiness in the process of operation with different strategies.
From an economic point of view, the preferred strategy will probably be the one that will ensure the minimum cost of maintaining the rolling stock in working condition. As studies have shown (Fig. 2.4.) and according to economic criteria during the period of running-in and normal operation of the rolling stock, the most preferable is also the planned strategy for the implementation of impacts.
Rice. 2.4. Graph of changes in the costs of maintenance and repair of vehicles during their operation with different strategies.
According to the foregoing, of all the indicated strategies for technical impacts, the planned strategy "B" is more effective. However, it should be taken into account that the planned strategy provides for a large volume of diagnostic work, detection and elimination of faults in the process of carrying out preventive maintenance, which is not always possible in practice due to the low resolution of diagnostics or the lack of necessary diagnostic equipment. Therefore, in the production of maintenance and repair of vehicles, a planned strategy is used to perform routine maintenance, and a random strategy is used to eliminate self-manifested and identified breakdowns and malfunctions.
In view of the foregoing, in the world practice, a planned preventive system for performing technical actions is used to maintain vehicles in working condition. This system consists in planned (preventive) execution maintenance work for maintenance and repairs as required. The choice of modes of planned technical impacts is important for ensuring a given level of non-failure operation of vehicles and reducing the cost of their maintenance and repair. There are various methods for establishing rational maintenance regimes: technical - economic; economics - probabilistic; probabilistic, etc.
The technical and economic method consists in determining the frequency of maintenance L opt by the minimum specific total costs 
for maintenance and repair of vehicles per unit of mileage (Fig. 2.5).
Rice. 2.5. Technical and economic method for determining the frequency of maintenance.
Due to the different modes of operation of cars, their units and parts, the need for their repair also arises through various runs.
Different periodicity of maintenance and TR require parts, assemblies, assemblies with different reliability indicators (Fig. 2.6.). However, given that it is practically 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) of 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 according to 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 pattern 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 no-failure operation.
With this method of determining the frequency of impacts, it becomes possible to manage the reliability of the car fleet, which consists in assigning service intervals that provide a given level of reliability (probability of failure-free operation) of various groups of parts and assemblies.
According to the existing provision for MOT and TR, the car is routinely installed (by mileage or calendar terms) for the next maintenance, during which a pre-planned amount of routine maintenance is performed in specialized areas. The list of works associated with maintenance repairs and some routine maintenance is specified when diagnosing a car.
Diagnostics reveals failures and malfunctions of the car and determines the amount of work to eliminate them. Identified failures and malfunctions are eliminated in the main production using units and assemblies repaired in auxiliary production shops.
At the current level of development, diagnostics cannot yet establish the technical condition of all individual connections of vehicle components and parts, the testability of which ranges from 0.5 to 0.74. As a result, 25 - 50% of all car maintenance work has to be regulated by the implementation of the corresponding range of work. Diagnostics can detect failures of individual systems and components with a probability (reliability) of 0.8 - 0.85. According to the research, up to 40% of all malfunctions are self-manifested failures that are eliminated in the current repair area.
In the future, with the development of the design of vehicles and diagnostic tools, it is expected to increase the overall testability of vehicle components and assemblies and the resolution of diagnostics, which will help reduce the amount of work of random effects and increase the likelihood of trouble-free operation of the rolling stock.
Organizational structures and methods of operation of the M&T system
The interconnected and orderly work of individual units of the system is the essence of the organization of the work of the system as a whole. Therefore, for the analysis of the operation of the TO and TR system, of particular interest is the se organizational structure. 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 order of work.
The organizational structure of the MOT and TR system of cars depends on the principle of work, in accordance with which the technology of the production process is built. The principle of production can be of two types: technological and subject. In the first case, production is based on technological operations (EO, TO-1, TO-2, TR), in the second - a car (unit) and its ability for trouble-free transport operation.
Rice. 2.8. Organizational structures of the system of TO and TR of cars in the ATP.
The choice of a production structure with a rational, technologically justified distribution of work among shops, sections and workplaces, taking into account specific conditions and technological links between all subsystems and their elements, is the basis for making many organizational decisions. The production structure of the maintenance and repair system must comply with the adopted strategy and organization of its work.
Three types of production structures are used in ATP: 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 specializes in
performing only one of the types of technical impacts (EO, TO-1, TO-2, TR), which ensures the technological homogeneity of each section, increases the productivity of work due to specialization.
With the existing planned 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 systemic principle of the relationship between various types of technical influences, the management of the entire system as a whole becomes more complicated, because 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 pay for labor according to the final result. The most significant drawback of this type of structure is the low quality of car maintenance and repair, which leads to an increase in random failures, an increase in downtime in repairs and a decrease in the technical availability of the car fleet.
The subject structure of production can be built according to subject automobile or subject aggregate principles.
With an 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 by a group of units for the entire fleet of vehicles is specified. But it should be noted that with such a structure, the systemic 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 the practice of the work of the ATP has shown, the use of an aggregate structure is the 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 units, but the car as a whole. With such a structure, maintenance is carried out according to the need, determined by the diagnostics, by one integrated team for one vehicle entry into the system. This makes it easier to take into account the assessment of the quality of work performed by the team in terms of the failure-free 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 among teams and the need for universalization of repair workers.
Given that the subject 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 improving the quality of maintenance and repair, it seems appropriate to use it when organizing work in the main production. The disadvantages inherent in this structure can be reduced through the appropriate organization of the work of complex teams and various managerial influences. So, when fixing repair teams for a group (column) of cars and simultaneously performing maintenance and repair work in one car into the system, it is possible to achieve high quality of work and a significant increase in the reliability parameters of cars in operation.
The mixed subject-technological structure of the organization of work has the advantages and disadvantages of the subject and technological structures listed above. A mixed structure is used in some ATPs to organize the work of the main and auxiliary industries. For example, according to the technological principle, work can be carried out on SW and TO-1, and according to the subject principle - TO-2 and TR. The structure can also be classified as mixed, when the units are repaired according to the subject principle, and the 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 has 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 influences. Car maintenance 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 work (lubricating, fastening, etc.) can be performed, 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 in-line 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 line tact. However, as we pointed out earlier, the volume of one or another impact on 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 operation of posts, which in a number of cases leads to loss of working time, downtime of equipment and rolling stock.
With a planned strategy for placing rolling stock into the system, it is most expedient to use the subject organization of work (automobile 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 performed at specialized posts, and in the main 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.
| Content | ||
| Introduction | 6 | |
| 1 | a common part | 8 |
| 1.1 | Characteristics of the rolling stock by brand and mileage | 8 |
| 1.2 | Equipment of the repair base | 9 |
| 1.3 | The existing technological process of maintenance and repair of vehicles | 10 |
| 1.4 | Analysis of the existing maintenance and repair organization | 11 |
| 1.5 | Characteristics of car maintenance | 12 |
| 2 | Settlement part | 14 |
| 2.1 | Selection of initial data | 14 |
| 2.2 | Calculation of the annual maintenance and repair program | 15 |
| 2.2.1 | Correction of the frequency of maintenance and TR | 15 |
| 2.2.2 | Correction of the labor intensity of maintenance and repair | 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 workshop | 22 |
| 2.2.6 | Calculation of the number of production workers | 23 |
| 2.3 | Selection of technological equipment | 25 |
| 2.4 | Calculation production area | 26 |
| 3 | Energy part | 27 |
| 3.1 | Calculation of the need for electricity | 27 |
| 3.2 | Heating calculation | 28 |
| 3.3 | Ventilation calculation | 29 |
| 3.4 | Water demand calculation | 30 |
| 4 | Technological part | 31 |
| 4.1 | Organization of maintenance and repair | 31 |
| 4.1.1 | Methods for organizing the technological process of car maintenance | 32 |
| 4.1.2 | The choice of the method of organizing the technological process of car maintenance | 33 |
| 4.1.3 | Organization of labor of workers at the posts of maintenance of cars. Designing the organization of work 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 maintenance and repair of 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 | Maintenance of the starting system | 40 |
| 4.2.3 | Maintenance of the ignition system | 41 |
| 5 | Economic part | 42 |
| 5.1 | Labor plan | 42 |
| 5.2 | Electrician Payroll Planning | 42 |
| 5.3 | Calculation of deductions for social needs | 44 |
| 5.4 | Cost of spare parts and materials | 44 |
| 5.5 | List of selected equipment | 45 |
| 5.6 | Calculation of depreciation charges | 47 |
| 5.7 | Calculation of costs for services servicing production | 48 |
| 5.7.1 | Calculation of fuel costs for heating | 48 |
| 5.7.2 | Calculation of electricity costs | 48 |
| 5.7.3 | Calculation of the cost of water supply | 49 |
| 5.8 | Plan at cost | 49 |
| 6 | Structural part | 51 |
| 6.1 | Device and principle of operation. Drive end cap assembly tool | 51 |
| 6.2 | Calculation of the strength of parts of the device for assembling covers | 53 |
| 6.2.1 | Calculation of the force acting on the part to be assembled | 53 |
| 6.2.2 | Calculation of the force developed by the pneumatic chamber | 54 |
| 6.3 | Calculation for the strength of a swivel joint | 54 |
| 6.3.1 | Finger check for shear | 54 |
| 6.3.2 | Checking the connection for collapse | 54 |
| 7 | Organization of work on labor protection and fire safety | 56 |
| 8 | Nature Conservation and Environmental Protection | 61 |
| 8.1 | Impact of 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 the 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 task is also confirmed by the fact that many times more labor and money are spent on the maintenance of a car than on its production.
At present, on the basis of scientific and technological progress, the planned preventive maintenance and repair system for the rolling stock of the timber industry complex as a whole, proven by many years of experience, is being further developed.
How to organize road transport, as well as in the area technical operation cars begin to apply various economic and mathematical methods of analysis, planning and design. New methods and tools for diagnosing the technical condition and predicting the resources for the uptime of vehicles are being developed and implemented more and more widely. 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 modern system management provides for new structural divisions of road transport - car factories and production associations, repair and maintenance bases, which potentially contribute to the transition to a centralized production of car maintenance and repair.
The most important task in any economy is the organization of maintenance and current repair of cars. This topical topic is the subject of the thesis project.
1 General
1.1 Characteristic mobile composition by make and mileage
Characteristics of the rolling stock available at the enterprise and engaged in the removal of timber (short log trucks), transportation of people and goods is shown in table 1
Table 1 - Characteristics of the rolling stock.
| № | brand car | Type 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 car | 2003 | 57099 |
| 7 | MOSKVICH-21412-01 | passenger car | 2001 | 109350 |
| 8 | GAZ-3110 | passenger car | 2003 | 114455 |
Table 1 shows that the rolling stock fleet has a small variety of brands. This, in turn, improves the quality of spare parts 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
cars
For maintenance of cars in the garage there is an integrated team that performs all types of maintenance and repair. When performing all types of maintenance, the following operations are performed.
Daily Maintenance (EO)
Cleaning the engine from dust and dirt;
External inspection check the absence of leakage of oil, fuel, coolant;
Check the oil level and top up if necessary;
Check the alternator belt tension.
Maintenance No. 1 (TO-1)
At TO-1, SW operations are performed, as well as:
Check the oil level and, if necessary, add it to the level of the control holes in the transmission units;
Check and adjust the devices of the power supply system and electrical equipment.
Maintenance No. 2 (TO-2)
At TO-2, TO-1 operations are performed, as well as:
Rinse the air cleaners;
Drain sediment from the filter coarse cleaning fuel;
Change the oil in the crankcase.
At the service season (CO), a check is made 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
Under the technological process of production is understood the sequence of technical influences on the car in the AP. The scheme of the technological process at the designed ATP is shown in Figure (3.1)
Checkpoint - checkpoint; EO- daily service; TO- technical service; TR- Maintenance; D-1,2- general and advanced
diagnostics.
Figure 3.1 - Scheme of the technological process of technical
maintenance and repair in ATP
At the checkpoint, inventory and technical acceptance of cars from the line is carried out and the documentation accepted at the AP is drawn up. Then the cars in the EO zone are cleaned and washed. Further, all serviceable cars are sent to the storage area, and those in need of maintenance and repair are sent to the corresponding production areas.
After the maintenance and repair, the vehicles are also sent to the storage area. If the number of cars returning from the line per unit of time is greater than the capacity of the EO zone, then some of the cars after the checkpoint do not go to the EO zone, but to the storage or waiting area for maintenance and repair. These vehicles pass the EO later when the EO area is not loaded.
For cars waiting for MOT and TR, there are waiting posts in the corresponding zones.
Some buses after the EO are subjected to diagnostics before maintenance and repair, and then they arrive at the service and repair posts (Figure 3.1). Release of cars on the line is carried out from the storage area through the checkpoint.
During the TR of a car, dismantling and assembly, metalwork, welding, adjustment, fastening and other works are carried out, as well as the replacement of individual parts, assemblies, mechanisms, devices and assemblies. During the TR of the unit, the same work is carried out, but with the replacement of individual parts that have reached the maximum permissible state, except for the basic ones, in order to reduce vehicle downtime, the current repair of vehicles at the ATP is carried out mainly aggregate method from the revolving fund.
Works on repair of units are carried out in the aggregate department.
Electrical work is carried out both at the posts of maintenance and repair, and in the electrical department.
Battery work consists in recharging, charging and repairing batteries and they are performed in the battery compartment.
Fuel equipment repair work is carried out both at the maintenance and repair posts, and in the department for the repair of power system devices.
Tire fitting and tire repair works include dismantling and mounting of tires, repair of wheel rims and tubes, wheel balancing.
Works on the manufacture of fasteners, mechanical restoration details after surfacing, boring of brake drums, milling of damaged surfaces, etc. are performed in the fitter-mechanical department.
Reinforcing, wallpaper, tin works are technologically related and are carried out in the respective departments.
Maintenance and repair of technological equipment, buildings and structures at the ATP is carried out by the department of the chief mechanic (CMO).
For storage of spare parts, parts, operating materials, units, etc. appropriate storage facilities exist. For storage of spare parts and units from the working capital there is an intermediate warehouse.
Justification, calculation and description planning solutions
General plan automobile enterprise
Previously, to build a master plan, the required area of the site is determined as
where - building area of industrial and warehouse buildings, m 2;
Building area with auxiliary buildings, m 2;
The area of open areas for storage of PS, m 2;
The area of the gas station, m 2;
Kz - building density of the territory,%.
Kz is adopted in accordance with SNiP II-89-80, indicated in table 3.1.
We accept for building a plot for ATP - a blocked type of building.
All major industrial premises will be located in the same building. Since there are more than 10 service posts at the planned ATP, in accordance with SNiP-II-93-74, a separate building can be designed for car washing. This means that a separate building is needed for the SW.
For industrial buildings, we accept a one-story building scheme.
All production and auxiliary zones and buildings on the master plan are located in accordance with the functional diagram and the scheme of the TO and TR technological process.
On the territory of the ATP traffic Vehicle carried out on the principle of one-way ring traffic. This excludes the possibility of meeting flows and their intersection.
Since the ATP provides for the storage of vehicles in open areas, the territory of the enterprise must have fences 1.6 m high.
We accept one checkpoint for entry and exit of cars. In addition, it is necessary to provide one spare gate.
Since one-way traffic will be carried out on the territory of the ATP, we accept the width of the passages at least 3 meters.
The minimum distance from the edge of the driveways to the outer wall of the building is taken to be 3 m in the absence of cars entering the building and 8 m in those areas where it is necessary to enter the building for trucks and cars. Since the width of the buildings on the territory of the ATP is less than 100 m, it is necessary to ensure the access of fire trucks to them from at least two sides.
The distance between sites for open storage of vehicles and buildings and structures are accepted in accordance with SNiP-II-60-75
(Table 3.3).
We design the administrative building as a separate building. Connected to the production building by a heated corridor. The entrance to it is carried out from the territory of the ATP. Next to the administrative building outside the territory of the enterprise, we are designing an open area for parking vehicles belonging to the employees of the enterprise. The area of one place is 25m 2, the parking lot consists of 35 car places, the parking area will be 875 m 2
To treat wastewater before entering the external sewer network or for reuse, a Kristall treatment plant is provided. There are also tanks for collecting rainwater.
We have a gravity pipeline for sewage disposal from car wash stations with a slope of at least 0.03.
The arrangement of cars in the storage area will be carried out according to scheme 4, figure 3.3.
The width of the driveways in open areas for storing cars is determined using templates, taking into account the conditions: cars are installed on the storage places in the forward direction when cars are installed on the storage places in the forward direction, it is allowed to turn them in the passage with a single activation reversing; the distance between moving cars and standing ones, as well as the car and buildings and structures must be at least the outer protective zone. The width of the protective zones during the storage of vehicles in open areas is stipulated by SNiP-01-80 (Table 3.5).
On the territory of the ATP, landscaped areas for recreation are provided. The dimensions of the sites are determined on the basis of at least 1 m2 per worker in the most numerous shift, i.e. not less than 80 m2. However, due to the uselessness, we accept a platform with gazebos in the green zone of the ATP as a recreation area.
On the territory of the enterprise, landscaping with a total area of approximately 15% of the area of the enterprise is envisaged, i.e. approximately 12600 m2.
The built-up area is defined as the total area of buildings and structures in the plan, sheds, open areas for car storage, warehouses, reserve sites. The built-up area does not include the area of roads, sidewalks, blind areas, green spaces, recreation areas, open parking lots for individual use.
The building density of the territory of the enterprise is defined as the ratio of the built-up area to the area of the site (in %).
The coefficient of use of the territory is defined as the ratio of the area occupied by buildings, structures, roads, sidewalks, blind areas, recreation areas, open areas, landscaping to the area of the enterprise site.
Space-planning solution for ATP buildings
The designed schemes and dimensions of buildings with a rectangular system of modular coordinates are established by GOST 23837-79 “Buildings of industrial enterprises. Dimensional schemes” and GOST 23838-79 “Buildings of industrial enterprises. Options".
The total area of the premises that will be located in the main production building is determined. The approximate total area of the main production building is determined by the formula:
where , , are, respectively, the total areas of production zones, departments and storage facilities that will be located in the building, m 2;
Coefficient taking into account the area of the building for passages and driveways,
This takes into account the following: the EO zone, the diagnostic department, the painting department will be located in separate buildings; administrative and amenity premises will be located in a separate administrative and amenity building, connected to the production building by a closed passage. Then:
Now let's select a grid of columns. The pitch of the columns for the entire building must be constant. We accept the step as 12 m. The length of the building is L=84 m. The span is assumed to be variable: 36-36-36-24-24-36-36-36 m.
Columns take the following dimensions: 600x400 mm. Intermediate (technological) columns must be installed at the outer walls every 6m.
Wall thickness: external -380mm, internal 120mm; window width - 2000.
The layout of the premises in the building is carried out in accordance with the technological process, production links between zones, departments and warehouses, construction, sanitary and fire safety requirements.
Maintenance zone posts have natural lighting. There are 9 workers and 3 waiting posts in the maintenance area. All of them are universal, ditch, equipped with ditch lifts. There are 5 ditch posts and three specialized posts in the TR zone. In addition to the existing equipment, there are two overhead cranes.
For better use daylight we place all production sites along the perimeter of the building, i.e. along the outer walls.
The sites serving the TO zone: electrical, fuel equipment, battery, tire changers are located near this zone.
The sites serving the TR zone: metalwork-mechanical, aggregate, etc. are located near this zone.
We design welding, tire sections with the introduction of a car outside the building
Warehouses for spare parts and assemblies are located near the TR zone.
Warehouse of paints and varnishes is located next to the paint-preparation room in the painting department.
battery compartment we design from 2 rooms - a room for a room for the preparation of electrolyte and a charging room.
The oil storage is located in the basement under the pump room and switchgear close to the maintenance area.
The tire warehouse is located next to the tire fitting department, which is located in the same room as the vulcanization.
Warehouses for spare parts, parts, assemblies and assemblies, as well as the aggregate department are equipped with crane beams. In the middle part is the MCC and a rest room. There is a bathroom at the main entrance.
Ditch posts in the TO and TR zones are interconnected by an underground trench of 1 m. The entrance to the ditches is carried out by stairs. Crossing bridges with a width of at least 0.8 m are laid across the ditches.
The layout drawing of the main production building of the ATP, made on a scale of 1:400, is shown on sheet No. 2.
