What is a sequential gearbox and how does it work. What is a sequential gearbox? Sequential box was installed by Mercedes

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Here it turns out that one rod is pulled up at the moment of switching, and the other is pressed. That is, at the moment of pulling up the first gear shift rod, the second gear shift rod is pressed. This made it possible to significantly reduce the switching time interval in comparison with regular box gears.

Translated from in English sequential is translated as a sequence. Therefore, a sequential gearbox means only sequential gear shifting. This principle of operation is to influence the control of the foot (an example is a motorcycle), for a quick switch - a sports car; in the case of a large number of gears, the choice of which by shifting the lever is not very convenient - this is a tractor, trucks. Most often, switching occurs due to the displacement of the control from the neutral position. While the principle of operation of a classic gearbox is self-selection transmission.

Development of the sequential box

What kind of transmission boxes have not been created in the entire history of the automotive industry. So the creation of a sequential transmission did not pass by. Most often we hear manual or automatic transmission, but it is worth understanding that this is not the case, as there are many more options for shifting gears.

There is a difference between these checkpoints that is worth understanding. Take, for example, an ordinary car with a manual transmission. In this case, the driver independently makes the choice of speed transmission. That is, having accelerated, he has the opportunity to switch from third speed to fifth, or, conversely, when braking, switch from fifth to third. This mechanism can also be called a search mechanism, since the inclusion of gear speeds is completely dependent on the driver. Once again, I would like to note that the transmission can be any, the most important thing is that it should be in line with the driving mode and the loads on the car.

But as for the owners of a sequential gearbox, they are deprived of such an opportunity for free switching. This action can only be performed one value either up or down. That is, the shift will look like this: two-three-four or seven-six-five, which is typical for BMW motorcycles and for M1-M motorcycles. It is impossible to achieve another switch on such a box.

Sports type M

More recently, a seven-speed sequential gearbox has been developed. This is the first model of a 7-speed SMG gearbox in the global automotive industry. Due to its ultra-fast shift times, combined with the power power unit it allows its owner to make his own choice of sporty or comfortable riding style.

Historical information

Such a box has already managed to become traditional for BMW cars. Already in 1996, SMG 1 began to be installed on the E36 M3 model. In 2001, the E46 M3 models were equipped with SMG 2. And already in 2005, the SMG 3 gearbox was installed on the E60 M5 model. What distinguishes this gearbox from previous models is a noticeable reduction in gear shift time.

This third-generation transmission model is equipped with individual shift linkages, allowing for a noticeable reduction in linkage at the time of shifting. How could this happen?

How does the switching process work?

Comparing a conventional gearbox with a sequential SMG 3, you notice that in a conventional gearbox, at the moment of shifting, the gear shift rod is pulled up, after which it turns and is pressed. In the compared device, everything happens differently. Here it turns out that one rod is pulled up at the moment of switching, and the other is pressed. That is, at the moment of pulling up the first gear shift rod, the second gear shift rod is pressed. This made it possible to significantly reduce the shift time interval in comparison with a conventional gearbox.

Operation of the sequential gearbox

So, the familiar manual transmission has evolved and made it possible to come to a new type of transmission, which should simplify the driver's control of the car. And such an important invention was the automatic transmission, which was modernized and improved. And today, it gives the driver the opportunity not to think at all about what and when to switch gears. But also mechanical equipment nobody pushed aside. It also continued to develop and now the result of these studies was a sequential gearbox. The result of such a transmission was the inclusion of speed in strict sequence.

Principle of operation

This type of gearbox was developed on the basis of mechanics. The main difference between this transmission is that instead of helical gears, gears with straight teeth are installed here, and there is also no clutch pedal (the electronic control unit took over this role). Gear shifting in the box is carried out using a hydraulic mechanism, which leads to a significant reduction in gear shifting.

The installation of a gearbox with a sequential mechanism has found particular distribution in racing cars. Realizing that such a sequential gearbox would be especially convenient for racing drivers, it meant that it was necessary to carry out such an installation on racing cars. This is explained by high speed promotes strong vibration car and in this case it is difficult for the driver to get into the required gear, while the sequential gearbox is able to cope with such a task.

Advantages and disadvantages

This sequential transmission has its own characteristics. The advantages of this unit include the absence of a clutch pedal, which is especially convenient for novice drivers. Following positive quality, which characterizes this model of the device - the speed of switching speeds, which exceeds the classic automatic and mechanical transmissions. Another advantage is efficiency, which occurs due to reduced gear shifting. It also offers the possibility of choosing a mode - mechanics or automatic.

The disadvantage of this device can be called its design. That is, this mechanism is not resistant to wear and quickly fails under heavy load. An example is racing cars. After each race, the sequential gearbox most often undergoes a mandatory bulkhead. In principle, if you do not follow the operating rules, then the sequential gearbox can fail on serial cars, which means it will entail expensive repairs.

If you need a car that will quickly accelerate to 100 km / h, have high dynamic and speed performance, you should pay attention to the transport where it will be installed sequential type Checkpoint.

What is a sequential gearbox?

Sequential gearbox disassembled

The sequential gearbox provides a dynamic ride, as well as ease of control of the machine. The speeds are switched in a strict sequence. This type of checkpoint became widespread in the mid-1990s.

The principle of operation of a sequential gearbox. The selector is used to change speed modes. The box competes with well-known types of gearboxes. Despite the fact that there is a clutch, it is controlled by an electronic unit.

Schematic representation of the checkpoint

It should be noted that the weight of the sequential gearbox is light. Despite this, a large moment of force is generated. It is based on gears that have straight teeth, a servo drive based on a hydraulic basis. This is the reason why speeds change quickly. Available gear activation clutches are a series of cams. The sequential gearbox does not allow the motorist to make a free choice of gears, i.e. jump over several at once.

Therefore, machines where installed this species boxes, are characterized by a high speed of switching speeds. Since the box is based on hydraulic system, the responsiveness of transport is noted.

Machines with sequential box

BMW M3 with sequential gearbox

Meet this box maybe on cars BMW brands, where there are individual drive rods that provide gear changes. In particular, on the foreign car BMW M5 E60, this unit contributes to an increase in driving dynamics. The machine is equipped on two axles with ventilated disc brakes, control exchange rate stability. It should be noted the presence of a double-disk clutch, two driving and driven disks, an intermediate disk. In addition to this version of the car, the specified type of box can be found on the BMW M3, mercedes benz C class. The listed cars belong to the category of sports.

Among domestic cars, this box is found on the VAZ-2108. The unit is a simplified version of standard mechanics. The operation of this device allows you to effectively maneuver, quickly switch from one gear to another.

Strengths and weaknesses of cam gearboxes

On a number of high-speed cars there is a cam gearbox. The advantage of this type of box is that it allows the machine to achieve high speed performance. The components of this gearbox can withstand high loads. Due to the fact that there are spur gears, there is an increased efficiency, less axial loads are created on the shafts of the cam gearbox. The switching mechanism for this gearbox is sequential (sequential). The change in speed occurs as a result of shifting the lever forward or backward. As a rule, cam gearboxes do not have synchronizers, which increased the speed of the box.

While driving, gear shifting is carried out without depressing the clutch, it is enough to release the accelerator pedal a little. When changing gears, rpm power plant do not fall, as a result, acceleration occurs faster.

However, the cam box has a number of disadvantages:

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

To extend the life of this checkpoint, it should, along with the entire car system diagnose periodically. In addition to this, change the oil. Otherwise, during prolonged operation, a large amount of metal particles will appear in the fuel. This helps to reduce the resource of the checkpoint.

Thus, sequential automatic transmissions can be found on race cars, motorcycles. This checkpoint is typical not only for passenger cars, but also for heavy vehicles. It is possible to switch speeds by means of paddle shifters, which is an advantage of the gearbox. Ease of operation is an additional aspect, why you can opt for a car with this box.

By creating a sequential gearbox, the developers set a goal to reduce the interval between gear changes. Due to the design features of such a transmission, this is achieved by simplifying the shift and the absence of operations with the clutch pedal.

This is especially important for novice and inexperienced drivers who have difficulty performing the shift procedures correctly. But professionals will also appreciate the gearbox, 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. The constructive sequential gearbox is a somewhat modernized “mechanics”, equipped with electronic unit and hydraulic mechanism (or electric servos).

Sectional sequential gearbox:

It should be mentioned that the engineers have also developed the so-called cam gearbox, which is structurally similar to a mechanical one. Differences from the usual "mechanics" - in the design of the gearbox clutch: instead of a crown with small teeth, it has several large cams (up to 7 pieces) that engage 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.

The cam-type gearbox is used mostly in sports cars and racing cars, due to its high speed and shifting accuracy. For everyday driving, its advantages are leveled by high cost, demanding consumables and rapid wear. In addition, the lack of synchronizers requires very precise actions from the driver, and a good skill is needed for “urban” driving at such a checkpoint.

What is Sequential Box

A sequential gearbox on a car implies that the driver does not select gears arbitrarily, but in a clear sequence, moving the gearbox selector in one of the directions. This is the difference between this box and the “mechanics”, where, after depressing the clutch, the lever can be moved to any of the positions.

Such a checkpoint is a relatively new invention, which 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 test results: studies have shown that with the help of such a gearbox, the driver can have better control over the car, compared to a classic automatic transmission, while still being able to influence the gear change process as effectively as " mechanics". Especially this advantage of the sequential unit is manifested where it is necessary to change the driving speed sequentially.

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

The appearance of the shift lever:

Shift "up" increases the transmission, "down" - lowers. Some vehicles may also be equipped with 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 switching if the box is operating in the “full” automatic transmission mode.

How it works

We all know what an automatic or adaptive and manual box is. In the first case, the system does everything itself, based 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 switch gears sequentially. Roughly speaking, if you can “jump” from 5 to 3 speed on the mechanics, then the sequence will not allow you to do this

There is a switching sequence that the SKPP cannot violate.

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

The mistake of many is that they consider SKPP an analogue of automatic transmission. In fact, mechanics were the inspiration for the creation of the sequence. It was built on the basis of the manual transmission.

Consider the principle of operation of this device and the key features of the SCP. So you will understand what it is and how the whole sequential system works.

The transmission does not have a clutch pedal. It pleasantly pleases those who do not have great experience driving. Management is simplified, no need to constantly squeeze the clutch. The electronics is responsible for it, receiving signals from sensors when reading pressing the gas pedal and switching on the gear. The box, having received a command from the control unit, sends a signal with sensors about the speed at which the car is currently moving. The progressive block is the last stage where the movement parameters are adjusted. He studies literally everything, from engine speed to on or off air conditioning.
In the design of the sequencer, spur gears are used. Their efficiency is higher compared to helical structures standing on the mechanics. The latter have impressive friction losses. Although spurs transmit less torque. To compensate for this, gears are put in large sizes.
Servo hydraulic type. The last distinguishing feature. Such a device switches between speeds. Now many are sure that the hydraulic servo drive 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 directly or the paddle shifters. This is a technology borrowed from racing cars that has taken root very well among the people. Especially in 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 it stands +) raises one gear up, and moving to the side with a “minus” allows you to lower the box by 1 gear.

That's what it means to be comfortable and convenient. It is not surprising that many seek to put a manual transmission on their car. Some craftsmen manage to shove a box onto the VAZ 2108 and 2107. There are also factory models that are 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 SKPP.

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 move off, we depress the clutch and shift into first gear. In the future, with a set of speeds, their sequential switching is recommended.

These gearboxes are much less likely to fail in unexpected overload situations. By using grease for lubrication instead of oil lubrication, there is less chance of loss of lubrication through the shaft seals. The reduced chance of lubrication loss 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 made with an eccentric cam at the end of the shaft. The cam is located inside the center of the cycloid disk. 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 the ring of fixed pins. When disc rolls move an internal 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, we, pushing the car, can immediately turn on the third, and even the fourth, to make it easier. Nothing prevents this. Decreasing the speed to perform a maneuver, we, having slowed down, from the fourth gear go immediately to the second or to the first. Having mixed up, 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 disk over one outer pin. As the disk spins, the internal pins are forced along with it at the speed of the disk. This means downshifting occurs and the output spins at more low revs than the input shaft.

The nature of the design makes them much smaller 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 staffed for installation and maintenance. Smaller internals and the sliding action of rotating components make the gearbox quieter than conventional gearboxes.

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 simplified the driver's control of the 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 engineers - it was also constantly modernized and modified, inventing more and more new gearshift mechanisms. One of the results of such research was a sequential gearbox - a transmission, characterized in that its gears can only be included in a strict sequence: up for upshifting, down for downshifting.

The principle of operation of a sequential transmission

This type of gearbox is built on the basis of a conventional mechanical transmission. Its main difference is that instead of helical gears there are spur gears, there is no clutch pedal (this role is performed 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, sequential gearboxes are installed most often. So, it is a gearbox with a sequential mechanism 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 right gear. And the sequential gearbox copes with this task by five plus.

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

Pros and cons of a sequential gearbox

Like any mechanism that works under load, the sequential transmission has its own characteristics.

TO positive aspects This unit includes the absence of a clutch pedal, which is important for novice drivers (if we are talking about using this type of transmission on production cars). The second positive factor of the selective gearbox is the gear shift speed, which is higher than that of classic automatic and manual transmissions.

The third advantage of this gearbox is economy - thanks to the reduced shift times. The fourth aspect is the choice of two gear shift modes (automatic or mechanical). Such a box is characterized by the presence of paddles on the steering wheel, through 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 failure. On the sports cars, where the loads are very high, such a box is often sorted out after every second race. For sequential boxes 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 overloads, like racing cars

And yet, if you operate the sequential box incorrectly (in manual mode, it is important to feel the moment and change gears in time), then it will not last long on a production car - 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 select a driving mode on a particular section of the road. The machine itself switches, while the driver, working with one foot, either increases speed or slows down. Driving a car with automatic transmission requires less skill, and it is not in vain that permission to operate such vehicle now placed in a separate category.

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

If you have any recommendations for maintenance maintenance of equipment, in particular the elimination of defects and the prevention of failure of equipment and equipment, or successful improvements in equipment reliability have been made, please feel free 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 switching of speeds.

Get the best reliability for your company on a global level

You can contact me by email. Now give your company a reliable system for world-class operational asset reliability, minimal maintenance costs and maximum operating profit. Most of these blocks can be easily replaced with the right interface parts. Major variations in the rear housing, rear clutch, and third control shaft match each other, as well as some changes to the outer bell configuration.

Sequential principle

Sequential gear changes can be noted, for example, on motorcycles, where they are switched on by foot. The neutral position there is most often located between first and second gear. The same mechanics are used on tractors, on big trucks. The greatest distribution series connection received in the boxes of sports cars, where every millisecond is precious and speed reduction when switching is unacceptable. The use of hydraulics allows you to further accelerate this process and reduce it to a minimum.

Low start position, 1" 10 spline input shaft, 1" 10 spline output shaft, external rear seal. On the right side There are two threaded holes on the bottom side of the main body, which are closed with screw plugs. In other applications, fat caps may be stored in these holes, which carry the cross shafts for the side rewind mechanism.

Also note 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 hull, using a different "spacer", speedometer drive unit 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 in the main shaft.

The sequential mechanism is based on a conventional manual gearbox, somewhat complicated in the process of modernization.
Main Feature is that with its help it is possible to carry out a downshift to an upshift without reducing the speed of the vehicle, which invariably occurs with the operation of a traditional gearbox.

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

Unlike the helical gears on a traditional car gearbox, the cam gears are spur gears and long. This makes it related 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, but instead of many small teeth on the gear and clutch, there are end projections. Those same cams that directly engage with the gap.

Also some indications that the front seal cover may have come from the factory earlier. The low position put the starter 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 gears. Combining the way of driving between the more comfortable manual system and the more controllable automatic by simply raising or lowering the lever, or, in more modern models, press the cams.

Design features

Sequential transmission is inherently a middle link between mechanical 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 switching moment is still selected manually, so it is still impossible to call such a mechanism fully automatic.

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

Advantages and disadvantages of the sequential box

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

Ease of shifting and high speed gear changes.

The ECU and hydraulics can reduce shift times to 150ms, which is critical for professional racers. This result cannot be achieved by any, even the most advanced, classic manual or automatic transmission.

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

The speed of the machine is not lost when switching.

When working with "mechanics" when changing gears, the speed is somewhat reduced. This is relevant for turbocharged engines that manage to fall into the turbo pit while the driver is manipulating the transmission.

Auto economy.
Ease of control thanks to the possibility of using paddles on the steering wheel.
Possibility of the choice of the mode - manual and completely automatic switching.

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

There are also disadvantages of a sequential gearbox:

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

While driving, gear shifting is carried out without depressing the clutch, it is enough to release the accelerator pedal a little. When changing gears, the speed of the power plant does not fall, as a result, acceleration occurs faster.

However, the cam box has a number of disadvantages:

relatively small working resource;
high price;
from an economic point of view, directly installing a box on a car in place of an existing one (automatic 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 passenger cars, but also for heavy vehicles. It is possible to switch speeds by means of paddle shifters, which is an advantage of the gearbox. Ease of operation is an additional aspect, why you can opt for a car with this box.

Advantages and disadvantages

Now you know what SCP is and what sequentiality means. Not? Yes, this is the sequence in translation. This is where everything falls into place.

After watching the video and studying the features of such a box, the question arises - is it worth taking a car from this checkpoint. I’ll help you a little by talking about the strengths and weaknesses of sequentials.

Let's start with the benefits.

High switching speed. The machine lives its own life, so sometimes it frankly blunts and does not do what you expect. The mechanics are harder to switch. The optimal speed is given by the SKPP. Electronic unit and hydraulics provide minimum costs time to transfer from transmission to transmission

For professional motorsport, this is extremely important.
Convenience. Depressing the clutch pedal, getting into gear, and even at speed on a bad road, is a dubious pleasure.

SKPP guarantees accuracy and comfort when switching. This is an indisputable fact.

No loss of speed. Yes, the sequential gearbox shifts quickly, there are no gaps between transitions, hence the measured ride, a quick set of speeds.
Fuel consumption. All the previous points affect the appearance of this advantage. SKPP carefully consumes fuel and helps to save.
Paddle petals. An additional option that allows you to feel like a racer. Comfortable and unusual.
Two modes. But I'll make a correction here. This automatic transmission has the function of switching to manual mode using a sequential system. So it's rather a plus of machines.

But not everything is so perfect. SCPP has two significant drawbacks.

Low resistance to loads and wear. The system is complex, consists of many elements and requires careful handling. You can’t just randomly click the petals or the lever. It is necessary to choose the right moment for switching. If this is not done, the mechanisms will quickly fail. It is not in vain that SKPPs are installed on the cars of professional racers.
Price. It is high on the car itself with a manual transmission and on the maintenance of such a box. Although if you have the money for a sequential car, the cost of repairing it shouldn't be a problem.

Minuses

But this box has its drawbacks. The hydraulic mechanism is subject to significant wear due to the heavy load during operation. On racing cars, mechanics repair the box after the second race. Mass-produced cars have a much greater durability resource.

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

Will it be a hydraulic clutch drive, another unit or unit, it is not so important. The main thing to remember is that the repair of a sequential box is very expensive.

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

The manual transmission can be either a simple robot with one clutch or a preselective gearbox with two clutches of the DSG type. In this article, we will talk about what a sequential gearbox is.

Read in this article

SMG box: sequential transmission

As you know, at the initial stage in the automotive industry, only a manual transmission was used.

However, in the future, engineers developed other types of transmissions, while the main task was to simplify driving as much as possible.

A real breakthrough was the emergence of an automatic transmission automatic transmission, which made it possible to realize the possibility of selecting and shifting gears automatically, that is, without the participation of the driver.

At the same time, the hydromechanical “automatic” did not supplant the traditional mechanics for a number of reasons, the manual transmission continued to be refined, the design was constantly improved. As a result, one of the varieties of manual transmission has become a sequential gearbox.

In a nutshell, such a transmission differs from analogues in that increased and downshifts are included only in a certain sequence. Simply put, the driver of a car with a so-called sequential shifts strictly in order “up” to turn on an increased gear, or “down” to turn on a lower gear.

At the same time, on conventional mechanics, the driver can shift gears according to the “search” principle, that is, arbitrarily. The main thing is that the transmission should correspond to the speed of movement, etc. In practice, for example, you can start from the second and immediately switch to the fourth. A sequential gearbox will not allow this.

The device and principle of operation of a sequential gearbox

As already mentioned, a sequential gearbox (sometimes called a selective gearbox) is based on a simple mechanical transmission. However, there are differences from the manual transmission.

Box DSG gear(DSG): design, principle of operation, distinctive features. Reliability, DSG resource, types of DSG robotic boxes, tips.

How to use a robotic gearbox correctly: "single-disk" robot, preselective robotic gearbox with two clutches. Recommendations.

AMT gearbox: device and operation robotic box gears, types of boxes-robot. Advantages and disadvantages of robotic transmission.

Most people interested in the automotive industry are accustomed to the fact that the car can move either with the help of a mechanical transmission, where all shifts are carried out directly by the driver from the passenger compartment of the car, or with the help of its more comfortable counterpart - an automatic transmission, which is independently responsible for switching gears. However, on automotive market there is also an offer for those who want to combine dynamism when driving a car manual transmission and the convenience of an automatic transmission - such a solution is called a sequential gearbox.

It is not difficult to understand what a sequential gearbox is by analyzing the meaning of the first word. The adjective "sequential" takes its roots from the English language and in literal translation sounds like "order" or "sequence". Accordingly, the presence of a car of this type of gearbox implies that speeds can only be switched in strict sequence. The choice of gear is carried out by moving the selector in only one direction, which is the difference from mechanics, where the gear can be selected in any order. Sequential gearboxes have been used by automakers since the mid-1990s. For example, the famous motorsport division of BMW installed the first generation of such boxes in their 3-series sports cars (M3 in the E36 body). Pre-sale testing has shown that a sequential transmission helps the driver tune the car to his driving style better than using an automatic transmission, while maintaining the ability to independently influence gear changes with the same efficiency as a manual transmission if a sequential change in speed is needed.

Sales of instances equipped with a sequential box showed that many drivers liked this alternative to more familiar counterparts, but some buyers could hear feedback about the relatively large shift interval. The situation was corrected by the release of the second generation of the sequential gearbox and integration into the company's new sports model with the M3 E46 index.

BMW engineers did not stop there, and already the third generation of sequential boxes has become distinctive feature their legendary M5 E60. With each new stage of development, the sequential gearbox was more and more adjusted by the designers to the needs of the consumer: the time spent on gear shifting was significantly reduced, while the dynamics of the car grew noticeably with each shift.

OPERATING PRINCIPLE OF THE SEQUENTIAL TRANSMISSION

The main task of a sequential gearbox, the principle of its operation when accelerating a car, is to reduce the interval between gear changes. The use of a sequential gearbox as a transmission achieves this not only by making the shifting process as simple as possible, but also by eliminating the need for the driver to operate the clutch himself. The absence of a clutch as an additional pedal gives an advantage both to novice drivers, for whom getting used to all the intricacies of the driving process presents some difficulties, and to pros who operate the car at the limit of its capabilities and for whom every fraction of a second is a lot of time lost during acceleration. In fact, the sequential gearbox also has a clutch, but it is controlled by a separate electronic unit, which independently calculates, based on the current speed of the car and the force of the driver on the accelerator pedal, which gear is in this moment the most optimal.

From this block, a signal is sent to the transmission, to the location of the speed detection sensors. The next and final point of sending the signal after processing by the sensors is the progressive block - the unit responsible for correcting the data on operation of the internal combustion engine. In addition to vehicle speed data, the progressive unit also processes information about the operation of all elements of the comfort unit and, based on the totality of the received data, performs calculations to optimize movement.

DESIGN FEATURES OF THE SEQUENTIAL GEARBOX

The sequential gearbox differs from its competitors in the following unique features:

the structure of a sequential gearbox is based on gears with straight teeth, and this is its main distinguishing feature from a mechanical box, where helical gears are taken as the basis. This difference lies in the advantage of a sequential gearbox, since spur gears, unlike their counterparts, almost do not create friction during the operation of the gearbox;
also, the diameter of each gear is slightly increased compared to those used for manual transmissions, which allows you to transfer more torque to the wheels;

Another characteristic feature of the sequential gearbox is the use of a hydraulic servo. Uninformed drivers sometimes confuse hydraulic-based servo drives with automatic transmissions, thereby making a mistake, since the design, working principle and efficiency of the result are significantly different.

ADVANTAGES OF A SEQUENTIAL GEARBOX

Undoubtedly, the transmission used in sports cars of the world's most famous manufacturers cannot but have a number of strengths that set it apart from other offerings. The advantages of a sequential gearbox are:

high speed shifting is the main plus of the gearbox on a sequential basis. The gear change really happens instantly - in just 150 m / s. The reason for such a high rate was the previously listed design features of the transmission: spur gears with an increased diameter and a hydraulic servo drive;
complete absence of loss of speed when switching - gears do not just switch at lightning speed, their change from each other does not affect the dynamics of the car in any way;

fast achievement of the maximum number of revolutions - the sequential gearbox interacts better with the car engine, due to which the gearshift occurs in the optimal ICE speed range for acceleration;
lack of recoil in the driver’s hand in the form of oscillations and vibrations - again, thanks to the well-established gearbox mechanism on a sequential basis, this kind of discomfort will not bother the owner of a car with such a gearbox;
reduced fuel consumption due to design features Checkpoint.

IMPORTANT: in cars with a sequential gearbox, even shifting using paddle shifters is much faster than in models with competing transmissions. This advantage can be decisive, for example, when competing on best result in a straight line.

DISADVANTAGES OF A SEQUENTIAL GEARBOX

Like other types of transmissions, the sequential gearbox also has negative aspects in operation:

relatively rapid wear- since cars with sequential gearboxes are usually driven very fast, and this driving mode and aggressive driving style are constantly maintained, this leads to frequent breakdowns and subsequent calls at the station after-sales service. The electronic load distribution unit in a sequential gearbox is an advantage during acceleration, but it can also cause a malfunction, since any untimely speed change completely violates the necessary algorithm and leads to destabilization of the entire system;

price Supplies and their replacement/installation work - just like with the electronic unit, the components of the sequential box are an advantage when it comes to speed characteristics, but the cost of repairing these mechanisms cannot be attributed to the advantages of this type of transmission. Repairing anything in it yourself is also a dubious prospect for the owner of a car with a box on a sequential basis.

IMPORTANT: when repairing the gearbox on a sequential basis, only original spare parts must be used. Since the design of such a box is significantly different from the mechanics and the machine, it will not work to replace most of the consumables with similar ones used in other boxes.

MISTAKE ABOUT THE SEQUENTIAL TRANSMISSION

For the layman, the most common are two incorrect stereotypes about sequential checkpoints. We explain:

is not another name for a robotic box. At its core, the first uses a hydraulic servo, and the second uses an electric one;
sequential gearbox It's no longer an automatic. Should not be confused automatic transmission with the possibility of switching to manual mode with a sequential analogue.

CONCLUSIONS ABOUT THE SEQUENTIAL GEARBOX
The sequential transmission will be an excellent solution for fans of dynamic driving and fast acceleration who do not want to completely give control of the car to the bail of modern electronic assistants, but at the same time they want to get not only the maximum drive and adrenaline, but also combine it with comfortable operation, without the need for unnecessary movements and operations.