What does a sequential gearbox mean and how does it work? Sequential gearbox: device, myths and advantages Cam and sequential gearbox differences

Automotive engineering has made great strides during its existence. Powertrain innovations are proof of this. On cars that exist today, you can find gearboxes of various types. An example of such a mechanism is a sequential gearbox.

What is a sequential gearbox

Wide use new technology in the field of transmission received in the 1990s. Such a gearbox is a gearbox that allows you to change speeds only in a sequential way. It differs from the usual version known to all in the mechanism of operation. Sequential switching was provided for those cases where the action on the control system is carried out with the help of the foot, as, for example, on motorcycles. The sequential gearbox is also relevant in cases with sports cars, when fast gear shifting is required. Application was also found in the case of a vehicle with a large number of gears. In this situation, traditional movement is inconvenient. This is typical for trucks and tractors.

Often these boxes have a mechanical type of work. But with the passage of time and the development of technology, the automatic sequential transmission is becoming more common. The difference from the conventional version is that there is a choice between manual and automatic gear shifting modes. Whichever type of work is used, the main feature is a strict sequence in switching. Down or up only. The driver either increases the speed or decreases it. Such an approach in the system of the mechanism makes the driving process easier for the driver and increases the speed of the transition from one speed to another. It is for this reason that the automatic adaptive sequential system has gained popularity among many car enthusiasts. Simplicity and convenience are two main components that complement each other.

How the sequential gearbox works

The basis for the sequential gearbox is the same familiar manual transmission. Only in this case it was improved: the design uses straight teeth of gears, instead of the common helical teeth. It is also based on a servo drive built on a hydraulic system. It is thanks to this that the speeds change quickly. You can schematically depict a box of this type as follows:

Attention! The sequential gearbox does not allow the driver to select gears independently, that is, to jump from one gear to another immediately after several.

Some motorists have a separate question about the sequential automatic transmission, namely, what it is. The answer is on the surface: it is an automatic transmission equipped only with sequential gear shifting (i.e. sequential). A significant difference of this type is the absence of a clutch pedal in the car and the way of switching the speed (only down and up).

Dealing with the question of the device of these structures, it is worth mentioning about the cam sequential gearbox. In terms of design, both options have similar characteristics. For example, both variants have both spur and long gears. They affect the speed of shifting from one gear to another. Determining which of these checkpoints is better is very difficult. Therefore, experts in this field have combined these two mechanisms into one.

The principle of operation of the sequential gearbox

As mentioned earlier, a sequential gearbox is characterized by the absence of a third pedal - the clutch. This feature is especially relevant for those drivers who have little experience in handling transport on the road. After all, the constant distraction of the left foot on the clutch pedal is a problem for many. But this does not mean that this mechanism missing in the gearbox. It exists, it only works differently. Consequently, the operation of the sequential checkpoint itself is different. The clutch is controlled by a special electronic unit, which, in turn, receives the necessary signals from the sensors. They determine the force of pressure on the gas pedal from the driver's side and control the activation of a specific speed. The gearbox receives a signal from the electronic unit, and that, in turn, with the help of sensors, transmits all the necessary information about the speed used to the progressive unit. It is here that the last process takes place - adjusting the speed limit based on the following indicators:

• the number of engine revolutions;
• air conditioner operation;
• the force of pressing the pedal, as well as a number of others.

The next principle of operation of sequential gear shifting is the used spur gears. If we compare them with the helical teeth, which are used in manual transmissions, they give out a higher efficiency. This is due to the fact that the first of them leave large losses during friction.

And the third feature of the operation of the sequential gearbox device is characterized by the presence of a hydraulic servo drive. Thanks to him, there is a quick change from one gear to another.

Important! Hydraulic servos and robotic gearboxes Are not the same thing. The differences lie in the device design: the latter uses an electric servo drive.

More detailed and visual information on how the sequential gearbox works can be obtained from the following video:

Which cars are equipped with a sequential gearbox

The sequential gearbox is most widely used for sports cars participating in races. For example, such a system of work is used in Formula 1 cars. Among the transport models on which this type of checkpoint is initially used, the following stand out:

• BMW M3;
• BMW M5;
• Mercedes Benz C-Class.

But the sequential box is much more common than meets the eye. As mentioned earlier, this type of device can be found on agricultural transport and on heavy vehicles. In the design of machines with a sequential gearbox, in this case, it became even more widespread.

Every driver wants to provide his car with everything necessary for a comfortable and safe ride. So some motorists install a gearbox with sequential gear shifting on their cars, specifically replacing the old transmission with a new one. Therefore, you can find the device completely at different transport... Very often, a sequential gearbox is installed on a VAZ. This provides the driver with an easier driving experience. In this case, preference is given to the cam system. Thus, this transmission can be installed on any car, the main thing is to choose the right model that is suitable in all parameters. There are a large number of options for a sequential gearbox on a VAZ. Therefore, there will be no problems in choosing or finding the right device. Moreover, some offer an individual assembly for the car by high-level specialists.

Pros and cons of sequential transmission

In order to figure out what to expect from a drivetrain, you need to consider its positive and negative aspects. Among the pluses, the following points should be noted:

• High speed and ease of gear shifting. Thanks to the electronic unit and hydraulic mechanism, the speed of transition from one speed to another is minimized. No other gearbox can boast of such indicators: neither mechanical nor automatic. Well, the main thing is that with the use of a sequential transmission, the driver does not have to frantically try to find the gear he needs at the moment. This is especially true when passing sharp turns or driving in a circle when it is difficult to keep the vehicle on the correct track.
• There is no loss of speed when shifting. This feature was loved in the circles of racers, and, of course, ordinary drivers also highly appreciated the presence of such an opportunity in the transmission.
• Thanks to the well-thought-out design of the sequential gearbox, fuel is consumed economically.
• Gear shifting with paddle shifters. This technology further simplifies driving while driving.
• Possibility to choose between automatic and manual gearshift modes. Of course, sequential transmission can exist separately from this function. But if, nevertheless, it is used, then this definitely refers to the pluses.
• The clutch pedal is missing. This is especially true for novice drivers who, due to their little experience, find it difficult to cope with manual transmission.
• When shifting the lever, you don't have to think about which gear to choose. The driver will simply either decrease or increase the speed.

Cons of sequential transmission:

• Sensitive to high loads and wear. It's not just about sports cars, but also simple civilian vehicles.

  Attention! As simple as it is to switch gears at the checkpoint, it is important to do it in a timely manner. If you neglect this point, then the system will quickly become unusable.

• High maintenance cost. The principle of the sequential box is a complex mechanism. The more complex the mechanism, the more expensive its maintenance.
• It is possible to achieve an increase in the power of the car by installing a sequential box only if you switch from higher gears to lower gears and vice versa in time. So the driver needs to feel good about his car, which is not always an easy task.

Conclusion

The sequential gearbox has given motorists new opportunities. The device and the principle of operation deserve attention from drivers, and the convenience of use is gaining an increasing number of consumers. Thanks to all of the above, a checkpoint of this type is becoming more widespread every year. And given all the positives of the gearbox, it's not casual.

Such a tricky and difficult to pronounce word for a simple Russian person, like sequential, is derived from the English sequence, which in translation means: sequence. And the English name sequential manual gearbox in Russian sounds like a sequential gearbox. This is a device on cars of a certain class that allows only sequential gear changes from the first to the increased one and vice versa, without jumping.

Traditional box

On traditional gearboxes installed on most domestic cars, the neutral position of the gearshift lever is set in the middle. In order to get under way, we squeeze the clutch and engage first gear. In the future, with a rise in speed, it is recommended to switch them sequentially.

However, nothing prevents us from starting immediately at the second speed, if the road condition is normal and the engine is designed for such an action. Trying to start the engine with a dead battery, while pushing the car, for relief we can turn on the third and even the fourth at once. Nothing prevents this. Reducing the speed to make a maneuver, we slow down, from the fourth gear we go directly to the second or to the first. Confused, you can turn on the wrong speed on the go, which is far from harmless for a car.

Automatic transmission

To simplify driving, an automatic transmission was invented, which freed the driver from the need to choose a driving mode on a particular section of the road. The machine switches itself, while the driver, working with one foot, either adds speed or slows down. Driving a car with automatic transmission requires less qualifications, and it is not for nothing that the permit to operate such a vehicle has now been allocated to a separate category.


But also work to improve mechanical transmission did not stop. As a result, a sequential transmission appeared, which also does not provide for the presence of a clutch pedal, but works on different principles. And its main feature is strictly sequential gear shifting.

The principle of sequencing

Sequential gear changes can be noted, for example, on motorcycles where they are engaged with the foot. The neutral position is there most often between the first and second gears. The same mechanics apply to tractors and large trucks. Sequential switching is most widespread in sports car boxes, where every millisecond is expensive and the speed reduction when switching is unacceptable. The use of hydraulics allows this process to be further accelerated and reduced to a minimum.

The sequential mechanism is based on a conventional manual transmission, somewhat complicated in the process of modernization. The main feature is that with its help it is possible to switch from low to high gear without reducing the speed of the vehicle, which invariably occurs during the operation of a traditional gearbox.

Cam or sequential

It must be said that a cam gearbox is installed on a number of racing cars. Although if the cam transmission is also made sequential, the already very high switching speed will be even higher. And this is already being applied on Formula 1 cars.

Unlike the helical gears on a traditional car gearbox, the cam gears are spur and long. This makes it similar to the transmission of a sequential box. And it is this feature that allows both systems to switch without slowing down. At the same time, the device of the box itself is simpler - there are no synchronizers, and instead of many small teeth on the gear and the clutch, there are end protrusions. These are the same cams that directly engage with the gap.

Peculiarities

On vehicles with a sequential gearbox, the shift lever is located on the steering wheel. Alternatively, buttons can be installed on the steering wheel. The required button is marked with the letter "S". Both automatic and manual switching are provided. In this case, the box can operate in three modes:

• Standard mechanical.
• Mechanical sports.
• With automatic changeover without driver intervention.

The advantages of this car of the future are the following points:

1. A car with a sequential gearbox, like an automatic transmission, does not have a clutch pedal - this is good for novice drivers.
2. This box provides a choice between automatic and manual shifting.
3. High gear change speed, which is reflected in the economy of the engine.

The disadvantage so far is the low wear resistance of the gearbox mechanism.

Creating a sequential gearbox, the developers set a goal to reduce the interval between speed changes. Thanks to design features This is achieved with such a transmission by simplifying shifting and eliminating clutch pedal operations.

This is especially important for newbies and inexperienced drivers who have difficulties with the correct implementation of the switching procedures. But professionals will also appreciate the checkpoint, thanks to its convenience and the ability to subtly feel and control the behavior of the car, using the maximum of its capabilities.

The principle of operation of the checkpoint, as mentioned earlier, is sequential switching, that is, the driver cannot "jump" from 5 to 2 gears, he needs to go through each one in turn. Constructive sequential gearbox is a somewhat modernized "mechanics" equipped with an electronic unit and a hydraulic mechanism (or electric servos).

Sectional sequential checkpoint:

It should be mentioned that engineers have also developed a so-called cam gearbox, which is structurally similar to a mechanical one. Differences from the usual "mechanics" - in the device of the gearbox clutch: instead of a crown with small teeth, it has several large cams (up to 7 pieces), engaging with similar cams on the gear. Such boxes are equipped with two switching mechanisms:

• search - the usual option, when you can arbitrarily turn on any transmission;
• sequential control system.

Cam-type gearboxes are used mostly in sports cars and race-ready cars due to their high speed and precise shifting. For everyday driving, its advantages are offset by high cost, demanding consumables and rapid wear. In addition, the absence of synchronizers requires very precise actions from the driver, and good skill is required for “city” driving at such a checkpoint.

What is Sequential Box

A sequential gearbox on a car means that the driver selects gears not randomly, but in a clear sequence, moving the gearbox selector in one of the directions. This is the difference between this box and "mechanics", where after squeezing the clutch, the lever can be moved to any of the positions.

Such a checkpoint is a relatively new invention that appeared in the early 90s of the XX century. Initially, racing cars were equipped with these units: for example, the BMW 3 Series sports cars from the motorsport division of the automaker. The choice of a sequential gearbox for equipping sports cars is dictated by the test results: studies have shown that a driver with the help of such a gearbox can better control the car, in comparison with a classic automatic transmission, while he still has the opportunity to influence the process of changing gears as effectively as on " mechanics ". This advantage of the sequential unit is especially manifested where it is necessary to change the driving speed sequentially.

The new box found the love of car owners, although some complained about some "slowness" of gearshift gear shifting. But the second generation of sequential boxes solved this problem too.

Shift Lever Appearance:

Shifting "up" increases the gear, "down" - lowers. Some vehicles may also have steering wheel switches for driver convenience. The role of the clutch pedal is performed by a hydraulic mechanism under control, the latter also takes over the shift if the gearbox operates in the "full" automatic transmission mode.

How it works

We all know what an automatic or adaptive and manual transmission is. In the first case, the system does everything by itself, relying on the current loads and the speed of the machine. That is, it adapts to the car. In the case of mechanics, you need to change gears yourself.

In the case of a sequential gearbox, it is important to note that it is distinguished by the ability to change gears sequentially. Roughly speaking, if on mechanics you can "jump" from 5 to 3 speed, then the sequencer will not allow you to do this

There is a switching sequence that the SKPP cannot break.

Initially, SKPPs were created for racing cars, Formula 1 cars and cars that take part in professional races. But the idea was liked by automakers, which is why many are introducing such boxes into civilian cars. And it pleases.

The mistake of many is that they consider the SKPP to be an analogue of the automatic transmission. In fact, mechanics served as the inspiration for the creation of the sequencer. It was built on the basis of a manual transmission.

Let's consider the principle of operation of this device and the key features of the SKPP. So you will understand what it is and how the whole sequencer system works.

1. The SKPP does not have a clutch pedal. This is a pleasure for those who do not have a lot of driving experience. Management is simplified, you do not need to constantly squeeze the clutch. The electronics are responsible for it, receiving signals from the sensors when reading the pressures on the gas pedal and engaging the gear. The box, having received a command from the control unit, transmits a signal about the speed at which the car is now moving by sensors. The progressive block is the last stage where the motion parameters are adjusted. He studies literally everything from engine speed to air conditioning on or off.
2. In the design of the sequencer, spur gears are used. Their efficiency is higher in comparison with helical structures standing on the mechanics. The latter have impressive frictional losses. Although the spur gears transmit less torque. To compensate for this, the gears are set to a large size.
3. Hydraulic servo drive. The last distinctive feature. Such a device switches between speeds. Now many are sure that the hydraulic servo is the property of robotic boxes. A common mistake, because they use electrical devices.

The sequencer works very simply. You can use the gearshift lever or paddle shifters directly. This is a technology borrowed from racing cars, which has taken root very well among the people. Especially at BMW and Toyota.

If you look at the box, you will see a lever on it that moves up and down. Plus there are additional modes, depending on the automaker.

Pressing up (where there is +) raises one gear up, and moving to the side with "minus" allows you to lower the box by 1 gear.

This is what comfortable and convenient means. It is not surprising that many people strive to put the SKPP on their car. Some craftsmen manage to shove the box into the VAZ 2108 and 2107. There are also factory models paired with a sequential one.

But I'll be honest. This is true for sports cars, from which you expect speed and minimal losses during acceleration. For a car with less than 150-200 under the hood Horse power, and which serve for family trips, there is no need for the UPC.

Traditional box

On traditional gearboxes installed on most domestic cars, the neutral position of the gearshift lever is set in the middle. In order to get under way, we squeeze the clutch and engage first gear. In the future, with a rise in speed, it is recommended to switch them sequentially.

These gearboxes are much less likely to fail in unexpected overload situations. By using grease for lubrication instead of oil lubrication, the likelihood of loss of lubricant through the shaft seals is reduced. The reduced likelihood of loss of lubrication is especially important for vertically mounted gearboxes as well as for agitators.

In the picture above, the center gray colored shaft is the input shaft. The same shaft is shown in the figure below. It is designed with an eccentric cam at the end of the shaft. The cam is located inside the center of the cycloidal disc. As it rotates, the cam moves the cycloid disk in a circular orbit. External fixed pins and rollers hold the disc and cause it to roll inside a ring of fixed pins. When the disc rolls move the inner set of pins and rollers attached to the output shaft.

However, nothing prevents us from starting immediately at the second speed, if the road condition is normal and the engine is designed for such an action. Trying to start the engine with a dead battery, while pushing the car, for relief we can turn on the third and even the fourth at once. Nothing prevents this. Reducing the speed to make a maneuver, we slow down, from the fourth gear we go directly to the second or to the first. Confused, you can turn on the wrong speed on the go, which is far from harmless for a car.

One turn of the cam moves the cycloid disc over one outer pin. As the disc rotates, the inner pins are forced along with it at the speed of the disc. This means that there is a reduction in gear, and the output rotates for more low revs than the input shaft.

The nature of the design makes them much smaller in size than a conventional gear reducer for the same transmission ratio. This means you need less space to mount them. They weigh less and are lighter in the number of installation and repair personnel. Smaller internals and sliding action of rotating components make the gearbox quieter than conventional gearboxes.

Sequential gearbox

Sequential gearbox

The evolution of the manual transmission led to the invention of a number of types of transmissions, which in one way or another made it easier for the driver to drive a car. An important step in this regard was the invention automatic box gear, which was subsequently transformed and improved, allowing the driver not to think at all about when and how to switch to the desired gear. But the mechanical transmission did not go unnoticed by the engineers - it was also constantly modernized and modified, inventing more and more new gear shifting mechanisms. One of the results of such research was a sequential gearbox - a transmission, characterized in that its gears can only be switched on in a strict sequence: up to increase the gear, down to lower.

How sequential transmission works

This type of gearbox is built on the basis of a conventional manual transmission. Its main difference is that instead of helical gears there are spur gears, there is no clutch pedal (this role is played by the electronic control unit), and the gears in this box are switched using a hydraulic mechanism

This significantly (up to 150 milliseconds) reduces the shift speed, which is most important for sports cars, on which, by the way, the sequential gearbox is installed most often. So, it is the sequential gearbox that is mounted on racing cars participating in Formula 1 and other similar competitions.

The designers realized that a gearbox with such a mechanism would be the most convenient for the rider, because when driving at high speed, when the car is subject to vibration, it is quite difficult to get into the desired gear. And the sequential gearbox copes with this task for five plus.

However, for more than a dozen years, the sequential gear shifting mechanism has been used on "civilian" cars. In everyday life it is called "manual" mode and it is typical for automatic transmissions.

Pros and cons of sequential gearbox

As with any mechanism that operates under load, the sequential transmission has its own characteristics.

On the positive side of this unit is the lack of a clutch pedal, which is important for novice drivers (if we are talking about using this type of transmission on production vehicles). The second positive factor of a selective gearbox is considered to be the gearshift speed, which is higher than that of classic automatic and manual transmissions.

The third advantage of this transmission is its economy - thanks to the shortened gear change times. The fourth aspect is the choice of two modes of gear shifting (automatic or mechanical). Such a box is characterized by the presence of paddle shifters by means of which the driver changes gears without taking his hands off the steering wheel.

This box also has its drawbacks, and they lie in the design of the unit itself. The fact is that the hydraulic mechanism of the sequential gearbox is unstable to wear and, when driving under heavy load, is prone to frequent breakdowns. On sports cars, where the loads are very high, such a box is often sorted out after every second race. For sequential gearboxes used on production vehicles (BMW M3, M5, Mercedes-Benz C-Class) are characterized by a higher power resource due to the fact that they do not experience overload, like racing cars

And yet, if the sequential gearbox is used incorrectly (in manual mode it is important to feel the moment and switch gears on time), then it will not last long on a production car either - it may fail. hydraulic drive clutches and other components and assemblies of this transmission. And repairing a sequential gearbox is not a cheap pleasure.

Automatic transmission

To simplify driving, an automatic transmission was invented, which freed the driver from the need to choose a driving mode on a particular section of the road. The machine switches itself, while the driver, working with one foot, either adds speed or slows down. Driving a car with automatic transmission requires less qualifications, and it is not for nothing that the permit to operate such a vehicle has now been allocated to a separate category.

They are ideal where shock loads are expected because all parts are in compression rather than tension as is the case with traditional gear teeth. Their reliability and durability are outstanding! Disclaimer: Since the authors, publishers and resellers are not aware of the context in which the information provided in this article should be used, they are not responsible for the consequences of using the information contained or implied in any articles.

If you have any maintenance recommendations for equipment maintenance, specifically how to fix defects and prevent equipment and equipment failure, or successful improvements have been made to equipment reliability, please do not hesitate to send me your articles for publication on this website.

But work on improving the mechanical transmission did not stop. As a result, a sequential transmission appeared, which also does not provide for the presence of a clutch pedal, but works on different principles. And its main feature is strictly sequential gear shifting.

Get the ultimate worldwide reliability for your company

You can contact me by email. Now give your company reliable system to ensure the reliability of world-class operating assets, minimum maintenance costs and maximum operating profit. Most of these blocks can be easily replaced with the correct interface pieces. The main variations in the rear housing, rear clutch and third control shaft are matched, as well as some changes in the bell's external configuration.

The principle of sequencing

Sequential gear changes can be noted, for example, on motorcycles where they are engaged with the foot. The neutral position is there most often between the first and second gears. The same mechanics apply to tractors and large trucks. Sequential switching is most widespread in sports car boxes, where every millisecond is expensive and the speed reduction when switching is unacceptable. The use of hydraulics allows this process to be further accelerated and reduced to a minimum.

Low start position, 1 "10 spline input shaft, 1" 10 spline output shaft, external rear seal. On the right side of the main body, on the underside, there are two threaded holes, which are closed with threaded plugs. In other applications, these holes can store greasy caps that carry the lateral rolls for the side rewind mechanism.

Also notice the small reinforcing rib added on the bottom of the rear case at the rear attachment point. Internally, the main shaft is slightly larger aft of the main body using a different "spacer", speedometer drive device and lock nut

This minor change is not often reflected in current parts catalogs. For interchangeability, the rear housing can only be replaced with a corresponding change to the main shaft.

The sequential mechanism is based on a conventional manual transmission, somewhat complicated in the process of modernization.
The main feature is that with its help it is possible to switch from low to high gear without reducing the speed of the vehicle, which invariably occurs during the operation of a traditional gearbox.

To use the senior starter position in earlier vehicles, you need to install the later section of the front tunnel and the bulkhead panel of the frame. There are additional reinforcing ribs on the outside of the bell to reduce vibration and noise, as well as a thicker front flange on the top for mounting bolts. There is also a rubber shaft seal on the gearbox housing cover, which is interchangeable and often retrofitted with older units.

Unlike the helical gears on a traditional car gearbox, the cam gears are spur and long. This makes it similar to the transmission of a sequential box. And it is this feature that allows both systems to switch without slowing down. At the same time, the device of the box itself is simpler - there are no synchronizers, and instead of many small teeth on the gear and the clutch, there are end protrusions. These are the same cams that directly engage with the gap.

There are also some indications that the front seal cover may have been manufactured earlier. The low position put the starter motor very close to the bottom flange on the engine block. The high position put the starter very close to the distributor housing.

Please refer to technical equipment cardan shaft for variations of three different cardan shafts used to accommodate these various gearboxes. Combining a way of moving between a more comfortable manual system and a more controlled automatic, simply raising or lowering the lever, or, in more modern models, pushing the cams.

Design features

The sequential transmission is essentially the middle link between manual and automatic transmissions. This is true, because, in fact, on the one hand, the driver does not think about which gear is currently on. On the other hand, the moment of switching is still selected manually, therefore, such a mechanism cannot be called fully automatic.

The shafts have a set of gears on them different sizes, and these gears can be connected to each other in various combinations by changing ratio... The spring mechanism of the gearbox is triggered when the gear is shifted, and the shafts jump to the next position and vice versa. This is how the sequential mechanism functions, which, in fact, does not include any automation and electronics.

Sequential box advantages and disadvantages

The features of the sequential box and its design lead to obvious advantages:

Ease of shifting and high speed of gear changes.

ECUs and hydraulics reduce shift times to 150ms, which is critical for professional riders. No one, even the most advanced, classic manual transmission or automatic transmission can achieve such a result.

In addition to speed, the sequential box eliminates the "miss" past the desired gear, because the transition between them is carried out strictly sequentially.

Machine speed is not lost when shifting.

When working with "mechanics" when changing gears, the speed decreases slightly. This is relevant for turbocharged engines that have time to fall into a turbo lag while the driver is manipulating the transmission.

• The economy of the car.
• Ease of control thanks to the use of paddle shifters.
• Selectable mode - manual and full automatic switching.

This is true for sequential gearboxes that can work in automatic transmission mode. But this design option is not used everywhere, a sequential transmission is not necessarily combined with an automatic.

There are also disadvantages of a sequential checkpoint:

• Increased susceptibility to wear and stress.
• The units are very sensitive to operating conditions.
• The high cost of the box and its maintenance.
• Gearbox parts are quite expensive, and repairing it will also cost an impressive amount.

Strengths and weaknesses of cam gearboxes

On a number of high-speed cars there is a cam gearbox. Advantage of this type box is that it allows the machine to reach high speed indicators... The components of this gearbox allow to withstand high loads. Due to the fact that there are spur gears, an increased efficiency is noted, to a lesser extent, axial loads on the shafts of the cam gearbox. The gearshift mechanism for this gearbox is sequential (sequential). The change of speeds occurs as a result of the implementation of the shift of the lever forward or backward. As a rule, cam gearboxes do not have synchronizers, which increased the speed of the gearbox.

During movement, gear shifting is carried out without squeezing the clutch, it is enough to slightly release the accelerator pedal. When changing gears, rpm power plant do not fall, as a result, acceleration occurs faster.

However, the cam box has several disadvantages:

• relatively small working resource;
• high price;
• from an economic point of view, direct installation of a box on a car in place of an existing one (automatic transmission or manual transmission) is not a profitable solution.

Thus, sequential automatic transmissions can be found on racing cars, motorcycles. This checkpoint is typical not only for cars, but also for heavy vehicles. The speeds can be switched by means of paddle shifters, which is an advantage of the gearbox. Ease of handling is an additional aspect why you can opt for a car with this gearbox.

Advantages and disadvantages

Now you know what SKP is and what sequencing means. No? Yes, this is the same consistency in translation. Here, in general, everything falls into place.

After watching the video and studying the features of such a box, the question arises - is it worth taking the car from this checkpoint. I will help you a little by telling you about the strong and weak sides sequencer.

Let's start with the benefits.

High switching speed. The automaton lives its own life, therefore sometimes it frankly dulls and does not do what you expect. The mechanics are more difficult to switch. The optimal speed is given by the SKPP. Electronic unit and hydraulics ensure minimal time-consuming transition from gear to gear

This is extremely important for professional motorsport.
Convenience. Squeezing the clutch pedal, getting into gear, and even at speed with a bad road is a dubious pleasure

The SKPP guarantees precision and comfort when shifting. This is an indisputable fact.

• No loss of speed. Yes, the sequential gearbox switches quickly, there are no gaps between the transitions, hence the measured ride, a quick set of speed.
• Fuel consumption. All the previous points affect the appearance of this advantage. The SKPP uses fuel sparingly and helps to save money.
• Paddle shifters. An additional option that makes you feel like a racer. Convenient and unusual.
• Two modes. But here I will make an amendment. This automatic transmission has the function of switching to manual mode using a sequential system. So this is rather a plus of the machines.

But not everything is perfect. The SKPP has two significant drawbacks.

• Low resistance to stress and wear. The system is complex, consists of many elements and requires careful handling. You can't just flick petals or a lever at random. It is necessary to choose the right moment for switching. If this is not done, the mechanisms will quickly fail. No wonder the SKPP are on the cars of professional racers.
• Price. It is high for the car itself with the SKPP and for the maintenance of such a box. Although, if you have the money to buy a sequential car, the cost of repairing it shouldn't be an issue.

Minuses

But this box also has its drawbacks. The hydraulic mechanism is subject to significant wear due to the high load during operation. On cars participating in races, mechanics repair the box after the second race. In production cars, a much greater durability resource is laid.

When used, they do not experience the same stress as sports cars. Therefore, at correct operation the service life of a sequential box is not less than that of a mechanical or automatic box. But if you operate such a box without thinking about the consequences, then premature failure is guaranteed to you

It will be a hydraulic clutch drive, another unit or unit, it is not so important. The main thing to remember is that repairing a sequential box is very expensive.

Nowadays, sequential transmission is attracting more and more car owners. It is installed on many new models of cars and even motorcycles. The technology of this transmission is being improved and brought to perfection. The time is not far off when not only sports cars equipped with a sequential gearbox, and even a cam one, will use a convenient transmission, but many car owners will appreciate the advantage of sequential gear shifting.

Sequential - this word is difficult enough to pronounce for a Russian-speaking person, and all because it came to us from English (sequence) and means “sequential”. A sequential gearbox is most often one that can only change gears sequentially, for example, from first to second and higher, and also in reverse. Let's look at the principles of manual and automatic transmission and then move on to sequential to understand it better.

It is a manual gearbox that is installed on most domestic cars, so almost everyone met with it in practice, at least while driving in a driving school. Such a gearbox functions according to the following principle. The rocker plate can be set in the neutral position, which is in the middle between the gears. And in order to start moving, it is necessary to depress the clutch pedal and engage the first gear. In the process of gaining the speed of movement consistently.

But the driver can also start from second gear, if the road surface does not impede smooth movement and the engine allows such a maneuver. If the car does not start, we push it and we can turn on the engine even in third and fourth gears. To reduce the speed when cornering, we can even switch from fifth to second. In other words, you have to remember the main point: on a manual transmission, you can change gears inconsistently.

Automatic box

Engineers were somehow given the task of making it easier to drive, and it was then that the automatic gearbox was invented. Its appearance greatly simplified the process of driving, the driver no longer had to choose speed mode movement. The automatic machine selects the gear itself, and the driver controls it only by pressing the brake and gas pedals. It is much easier to drive a car with automatic transmission, and no special qualifications are required.

However, the process did not stop, which is why a more advanced cam sequential gearbox appeared. For its operation, too, a clutch pedal is not needed, as in an automatic one, but its operation is based on completely different principles.

Sequential box

As mentioned earlier, the sequential gearbox is based on the principle of strictly sequential gear changes. And since it is built on the basis of a manual gearbox, then in the course of the article we will periodically touch upon the principles of operation of a manual gearbox.

The first thing to remember is the lack of a clutch pedal for a sequential gearbox, which is a definite plus for those who have a hard time coping with three pedals. In fact, this gearbox has a clutch, but it is controlled by an electronic unit specially designed for this. This unit reads a signal from sensors that determine the force of pressing the gas pedal and calculate which gear should be switched on. Now this is not the task of the driver, but of the technician.

A command is sent from the electronic unit to the checkpoint, where special sensors are installed. They receive this signal and transmit a new command to the progressive block, where information about the speed of the vehicle is stored. The progressive block is the last element in the circuit and is responsible for adjusting the engine data. It receives signals from different sensors, from the degree of pressing the gas pedal, from the switched on air conditioner, etc. Based on these data, it calculates and corrects the speed limit.

Let's dig a little deeper, consider the structural component in more detail, perhaps someone wants to repair such a gearbox with their own hands. And for this, it is imperative to know all the nuances and principles of transferring motion to the shaft.

Only spur gears are included in the construction of the sequential box. Their use turned out to be more rational when compared with their helical counterpart installed in a manual transmission. Straight-toothed gears give a very high efficiency, and this is due to the fact that they practically do not create friction during operation. However, they also have a drawback, they transmit less torque, therefore, to compensate for this drawback, gears of a larger diameter are used.

And the last feature of the sequential box is hydraulic servos, it is their presence that allows the electronic unit to perform ultra-fast gear shifting. Servos based on a hydraulic component are confused by some drivers with automatic transmissions. And this is a very serious mistake, because structurally they are completely different: both their principle of operation and the efficiency at the output.

Benefits of sequential transmission

Let's take a look at what strengths this innovative gearbox has.

Instant switching

Indeed, this is the main distinguishing feature. Real transmission swiftly. Not to be fabulous, it's worth noting that the switch is about 150ms. This time period is achieved due to the presence in the system of an electronic control unit and a servo drive on a hydraulic principle. What's more, there is no loss of speed when shifting! The sequential transmission is a game-changer in motorsport.

With such a quick shift, none of the modern modifications of mechanical or automatic transmissions... Moreover, the car will now be much easier to keep on the roadway, because there will be practically no shaking and vibration. And you do not have to press the gas pedal all the way to "finish off" the number of revolutions before shifting to an upshift, as in an automatic transmission.

Economy

This point follows from the first, thanks to the well-thought-out design of the transmission, fuel consumption is very economical.

Paddle shifters

This technology has been around for a long time and is very popular among racers. And in a sequential gearbox, the shift speed is even higher, and the convenience is even greater.

Selecting a speed mode

The driver can choose to either automatically shift gears and drive without thinking about anything, or a manual one, which is called Sport Mode.

Disadvantages of sequential transmission

Wear

A high load leads to rapid wear of this type of transmission. And the conversation is now not about sports cars that you see on the Formula 1 race track, but about ordinary cars. The fact is that the presence of an electronic control unit makes the gearbox very sensitive to loads, in other words, to untimely switching. Another proof of the statement "The more complex the mechanism, the higher the probability of its breakdown." Of course, if you do everything on time and avoid unnecessary stress, such a transmission will be durable.

Expensive service

We examined the design of a sequential gearbox, it contains many electronic data meters and analyzer blocks. That is why the cost Maintenance such a transmission is very high.

Major misconceptions

Sequential transmission = robotic gearbox

This is probably the main misconception. Yes, these two gearboxes have servos available, but in the sequential gearbox they are hydraulic, and in the robotic gearbox they are electric. And this is already a technologically different implementation.

Sequential gearbox is an automatic gearbox

Most drivers draw this conclusion based on the fact that virtually all modern cars for permanent use (not sports cars), which are equipped with such a transmission, work only with the "automatic". This is the deepest misconception, firstly, there are models where you can choose between automatic shifting or manual shifting while driving. Secondly, remember the Formula 1 race and everything will immediately fall into place.

Output

Today, sequential gearboxes are becoming more and more popular and are installed on new models of cars and even motorcycles. Over time, this technology has been improved and brought to perfection. If we compare the first such transmissions that went into mass production on BMW cars in 1996, and modern counterparts - the difference will be colossal! And if a sequential transmission is installed on a car, which is also a cam-type transmission, then you get twice as many advantages. Most often, this technological solution is used in sports cars.

The car's gearbox is one of the most advanced vehicle components.

During the production of cars, fundamentally new gear shifting systems with different mechanisms were developed. One of these devices is a sequential gearbox.

Sequential gearbox: what is it

The concept of "sequential" comes from english word sequence which means "sequence". Gears in such a box are switched sequentially, from lowest to highest, and vice versa. This shifting principle is used in motorcycles where foot control is used. Indeed, it is difficult to perform complex manipulations when controlling gear changes with your foot. Therefore, we chose a simple algorithm: moving the lever up corresponds to an increase in the gear, down - to a transition to a lower gear.

Video - clearly shows how quickly the gear changes on the sequential gearbox:

There are some more vehicles, where a sequential checkpoint is traditionally used, military equipment (self-propelled artillery vehicles, tanks). They have their own specifics. First, they are driven by unskilled drivers. Secondly, there is a fast transition to an upshift with minimal "dips" in power during the shift. The second quality (the practical absence of dips in power and speed) determines the use of sequential transmission in high-speed sports cars.

Video - what does a sequential gearbox mean on a racing Peugeot car 208:

The principle of operation of the sequential gearbox

The design of the sequential gearbox in appearance differs little from the traditional manual gearbox.

If you take a closer look at the gear mechanism, you can immediately notice that the teeth are located strictly perpendicular to the side surface of the gear.

This is necessary to ensure that they move in a straight line during switching.

On the one hand, straight-toothed gears have less friction than skew-toothed gears due to the complete conformity of the surfaces. On the other hand, oblique gears in mechanical box designed to increase the torque that the gear train can handle. Therefore, in many sequential boxes, gears of increased width are installed. This increases the design of the teeth and their strength.

The design of the sequential gearbox makes it quite simple to organize automatic mode switching. There are the following sequential checkpoints:

• with a conventional mechanical gear shifting system;
• with a sports shifting system;
• with an automated switching system.

Hydraulics are used to increase the switching speed. With the help of hydraulic servo drives, the switching time is minimal. During the activation of the shift to another gear, the accumulator is filled, which contributes to the creation of pressure in the hydraulic system. The gear change time is a tenth of a second. This decisive fact determines the use of sequential gearboxes in sports cars. Often, the gearbox controls are placed in the steering column area, which further simplifies the control of the modes.

How does it differ from robotic

Many motorists mistakenly believe that the sequential gearbox is a close relative of the robotic one. Their fundamental difference lies in their use in a sequential box hydraulic system when shifting gears. The robotic box uses an electric drive for this. also in robotic boxes a different gear shifting mode is applied.

Video - shifting gears on the sequential gearbox of a racing car:

Their advantages and disadvantages

The main advantages of such boxes:

• minimum time for speed switching;
• minimum power losses of spur gears;
• fuel economy;
• the ability to switch from manual to automatic mode;
• the ability to control the shift from the steering column;
• using the system without using the clutch pedal.

Disadvantages of a sequential checkpoint:

• sequential gear shifting sometimes constrains the driver in terms of applying extreme driving styles, necessary gear changes, for example, when starting the engine "from the pusher";
• relatively high weight of the gearbox with the same power;
• reduced service life associated with the technical complexity of the mechanisms;
• high cost of maintenance and repair.

In which passenger cars can you find a sequential gearbox

Of the most common passenger cars an example of a 1996 BMW with an SMG gearbox. The SMG1 and SMG2 systems were installed on the BMW of the third series with the index S. Since 2004, such a transmission has been installed on the BMW E60 M5. Also, a sequential gearbox was installed on individual models cars Toyota Corolla, Mercedes S-class, BMW X5.

The layout of the sequential gearbox and its elements is shown in the figure:

In the figure: 1 - sequential gearbox control unit, 4 and 5 - indicator and mode switch, 7 - 6 stepped gearbox, 12 - hydraulic block, 10 - hydraulic drive, 11 - clutch.

Features of installing a sequential gearbox on VAZ cars

Many motorists purchase sequential gearboxes with a cam mechanism as an upgrade to their VAZ. Their appearance something like that.

As for the significant effect, it is not necessary to count on this, since the dynamics of the car at the same time, judging by the reviews of the owners, increases slightly, although these boxes are called "sports". In addition, the weight of such boxes is usually higher than traditional ones. There, wide massive gears with a perpendicular arrangement of teeth are used to compensate for their low load capacity.

In addition, spur teeth increase gearbox noise. The actual service life of a handicraft sequential gearbox is short. Such a gearbox can be installed if the car is supposed to participate in sports competitions, but not for everyday city driving.

conclusions

Summing up, it can be noted that the development and introduction into serial production of sequential gearboxes has made a certain technical progress in the development of the automotive industry. Such checkpoints were not widely used due to the presence of numerous shortcomings.

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