Such a tricky and hard-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, allowing only sequential gear shifts from first to high and vice versa, without jumping.
The gearbox is a variation planetary box gears. They have the added benefit of not using gear teeth to drive the shafts; instead, they use an internal cam shifter to drive rollers that turn a cycloid wheel inside the gearbox. The rollers are able to withstand 500% overload without breaking the gearbox. Another advantage of the cyclode drive for users is that many models are oil lubricated and do not use oil.
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 central gray colored shaft is 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.
Automatic transmission
To make it easier to drive a car, was invented automatic transmission gears, which freed the driver from the need to choose the mode of movement 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 for nothing that the permit to operate such a vehicle is now highlighted 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 recommendations for maintenance on equipment maintenance, 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 at e-mail. Now give your company a reliable system to deliver world-class operational asset reliability, lowest maintenance costs, and maximum operating profit. Most of these blocks can be easily replaced with the right interface pieces. Major variations in the rear case, rear clutch and the third control shaft correspond to each other, as well as some changes in the external configuration of the bell.
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 apply to tractors, big trucks. Sequential switching has received the greatest distribution in sports car boxes, 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 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", a speedometer drive unit, and a lock nut. This minor change not often reflected in current parts catalogs. For interchangeability back case can only be replaced with a corresponding modification of the main shaft.
The sequential mechanism is based on a conventional manual gearbox, somewhat complicated in the process of modernization. The main feature is that with its help it is possible to switch from a lower to an increased gear without reducing the speed of the car, which invariably occurs when a traditional gearbox is operating.
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 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 that is interchangeable and often retrofitted with earlier units.
Unlike the helical gears on a traditional conventional car box, 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 different gearboxes. Combining a mode of movement between a more comfortable manual system and a more controllable automatic, simply by raising or lowering a lever, or, in more modern models, press the cams.
Peculiarities
On cars with a sequential gearbox, the shift lever is located on the steering wheel. Alternatively, buttons can be installed on the steering wheel. Desired button marked with the letter "S". Both automatic and manual switching is provided. In this case, the box can operate in three modes:
They are also popularly referred to as semi-automatic transmissions. It is a manual transmission with hydraulic robotic command that has levers or levers that operate in counter-phase: right to lift, left to decrease, and use of the clutch on demand, making changes in 0-1 seconds possible.
Consolation of the civilian racer
Sequential manual transmission also applies to motorcycles where the change is via cams and the clutch is usually on the left handle. In cars, we usually find them on the steering wheel when they are electro-hydraulic, although in some cases we may find them purely manual or hydraulic without further ado.
- Standard mechanical.
- Mechanical sports.
- With no driver input.
The advantages of this car of the future are the following points:
- A car with a sequential gearbox, like with an automatic transmission, does not have a clutch pedal - this is good for novice drivers.
- This box provides a choice between automatic and manual switching.
- High gearshift speed, which is reflected in the efficiency of the engine.
The disadvantage so far is the low wear resistance of the box mechanism.
This type of box, moreover, is not designed to save fuel in any of its variants, since the most important thing is to quickly get the required power at every moment. Spain is not a country with a tradition of automatic changes, which is the case in the United States, where most vehicles are equipped with this type of transmission. Although in others European countries not much enthusiasm, Spain remains in line in demand for this type of gear.
The design of the cam gearbox
A higher price than the same car equipped with a manual transmission, more expensive breakdowns and higher fuel consumption have become the most important brakes on the success of automatic changes in Spain and Europe, especially among the most fanatical drivers. But there is a change in the trend, and little by little this type of transmission begins to gain followers. The reason lies in the evolution of automatic changes that even exceed manual speed and consumption. In addition, they may offer sports driving similar to a manual transmission when they include the ability to sequentially change with the paddles on the steering wheel.
Transmissions that are used in the rally, I would divide into several types.
1. Full stock.
Factory synchronized manual transmission. Without any changes. In motorsport and in rally, it is almost never used because the standard gearbox is designed for city-highway operation, and is too long for a rally and the car with it is slower than it could be.
Now the car's electronics have given way to a new generation of automatic changes that are smoother, faster, more efficient in consumption and offered as an option even in conventional medium and small vehicles. In addition, many "premium" models are sold only with an automatic transmission.
Torque converter automatic changes are the ones that have dominated the market in the last decade and are still supported today by its simple structure and resistance. It is indeed a manual transmission, but with an internal clutch system that prevents the driver from stepping on it. Overall, it reacts very similarly to manual, but with somewhat slower and less precise changes.
2. Tuning stock.
principle of operation of the synchronizer
When the main pair and gear ratios are changed, most often a limited slip differential (worm or disc) is installed, which greatly improves the dynamic capabilities of the car on slippery surfaces.
Among its advantages are ease of use, efficiency in consumption and efficient use of the engine brake. This helps keep the engine running. maximum power to achieve maximum acceleration and constant consumption. Against the price of this type of change and the higher cost of repairs than management in case of failure.
Changes in tenths of a second and with acceleration and consumption ratios better than their manual equivalent are the keys that attract many drivers. Its smooth operation also contributes to lower maintenance costs. On the contrary, we found its price to be always more expensive than a car with a manual transmission.
worm gear limited slip differential
Limited slip disc differential
The gearbox is still based on synchronizers and helical. Often used for tuning city cars. T.K. Compared to stock, it greatly improves the dynamics of the car. This is how rally driving looks like a checkpoint. This is my onboard from the Russian Rally Cup - Golden Dome Rally 2013
Reasons for buying or not having an automatic transmission vehicle
To sum up the biggest advantages of automatic change over manual we find it in the comfort it offers, the safest and most attentive movement to traffic without having to know about the pedal and lever and the mechanical safety it brings to the engine smoothness in gears . The result is a more dynamic and sporty driving experience, and is appreciated by drivers who are more akin to traditional modifications.
3. Cam gearbox.
It takes its name from the cam clutches, which replace the synchronizers and allow you to turn on quickly and without depressing the clutch to produce shocks, both up and down, the gear will turn on reliably.
The gears in this gearbox are spur gears. It is used together with a disc differincial of increased friction. This checkpoint is no longer used for urban tuning. has a reduced resource and high cost. This is what driving with a cam gearbox looks like, shifts are fast and without a clutch.
4. Sequential gearbox.
The difference from a simple cam gearbox is that instead of the usual switching scheme, this gearbox has a lever travel only forward (gear down) and backward (gear up). In fact, the difference is in the mechanism and principle of switching, and the clutches and spur gears are the same as in a conventional cam gearbox. On this moment in a rally this is the pinnacle everything else is prohibited. Such gearboxes are used on all modern and fast rally cars, including cars of the World Championship WRC rally. Here is an example of how driving with a sequential gearbox looks like
But back to my car.
When I bought the Logan, there was a JH3 box in its case, there was a symbiosis of a shortened Main Pair and a short row. This allowed the machine weak motor be much faster than standard logan. After driving in a Renault monocup, where changes in the gearbox were prohibited by technical requirements, I decided to further improve the dynamics of the car by installing a short final drive.
Transmission 4.9 (my former 4.5, factory 4.3) was found in Europe,
the table shows how the speed changes in gear, but unfortunately it is quite difficult to show how the dynamics of the car improves
though, unfortunately, it turned out to be not cheap, at the same time they strengthened the gearbox housing so that the increased torque from the internal combustion engine could be transmitted.
This eventually played a cruel joke. Due to poor-quality work performed by third-party specialists, the gearbox broke down 2 times, and then completely fell apart.
The reason was in the reinforcement plate, which was designed to hold seats shafts from displacement. After that I decided to switch to next level. Was bought new cam gearbox Baltic company samsonas.
With this transition, I simultaneously improved the dynamics of the car, increased reliability, improved handling. The fact is that in my previous gearbox there was no limited slip differential of the so-called "blocking". And in this gearbox, it is on-disk, which allows you not to lose on acceleration and improves cornering.
Such a tricky and hard-to-pronounce word for a simple Russian person, like sequential, is derived from the English sequence, which in translation means: sequence. AND English title sequential manual gearbox in Russian sounds like a sequential gearbox. This is a device on cars of a certain class, allowing only sequential gear shifts from first to high 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 move off, we depress the clutch and shift into first gear. In the future, with a set of speeds, their sequential switching is recommended.
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.
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. 
But work on improvement 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.
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. Sequential switching has received the greatest distribution 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.
The sequential mechanism is based on a conventional manual gearbox, somewhat complicated in the process of modernization. The main feature is that it can be used to switch from low to overdrive without reducing the speed of the car, which invariably occurs with the operation of a traditional gearbox. 
Cam or sequential
It must be said that on a number racing cars mobiles cam gearbox installed. Although if the cam transmission is also made sequential, it is already very high speed switching modes will be even higher. And this is already applied on Formula 1 cars.
Unlike helical gears on a traditional box ordinary car, the cam gears are spur 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. 
Peculiarities
On cars with a sequential gearbox, the shift lever is located on the steering wheel. Alternatively, buttons can be installed on the steering wheel. The desired button is marked with the letter "S". Provides both automatic and manual switching. In this case, the box can operate in three modes:
- Standard mechanical.
- Mechanical sports.
- WITH automatic switching without the participation of the driver.
The advantages of this car of the future are the following points:
- For cars with sequential gearbox, as with automatic transmissions, there is no clutch pedal - this is good for novice drivers.
- This box provides a choice between automatic and manual switching.
- High gearshift speed, which is reflected in the efficiency of the engine.
The disadvantage so far is the low wear resistance of the box mechanism.
sequential box
allows only the possibility of switching them one by one. From the box
the usual type differs in the method of operation of the gearshift mechanism.
The presence of alternate gear shifting is comfortable when
the action on the control is performed by the foot (for example, on a bike), when
will need a quick gear change (for example, on a sports car) or
in the presence of a huge number of gears, the choice of which in the traditional way of movement
lever is not so comfortable (on trucks). Ordinary switching is done by shifting the organ
control from the neutral position.
gear shift mechanism
may be a direct
action, for example both on bikes and with a servo drive (automatic or
not automatic).
On bikes, the following
box control scheme:
- movement
Lever Up - Gear Up - movement
lever down - gear DOWN - neutral
mediocrely placed between 1st and 2nd gears (sometimes apart from that and between
third-fourth), in addition, cuts in with an incomplete stroke of the lever.
On cars, ordinary
controlled by a lever, at the same time acting as a mode selector and
gear shifting, although it has the ability to be controlled by buttons,
located on the steering wheel.
On cars, ordinary
a lever is installed, it also plays the role of a mode selector and switching.
The buttons on the control wheel are used in the same way.
Sequential mode
classified by the Latin "S". The operation method of this box is based on the conventional
mechanical box, although it is somewhat modernized with this option.
Gears are switched with the introduction of hydraulics, and this is considered its main
difference from a mechanized box. The switches are made alternately
no speed overshoot. Switching happens like automatic,
as well as manual. There are usually 3 modes:
- Mechanical ordinary.
- Mechanical sports.
- Switching is automatic, in the absence
driver actions.
In regular boxes
gear shifting tighten the drive rod, turn and press,
as it should, the desired gear is “selected”. In a sequential box in advance
increases the pressure in the hydraulic unit and begins to fill
hydraulic accumulator, and then the gear shift occurs using
hydraulic work.
Distinctive features of racing
mechanics
Large wheel diameter
explained by 2 factors. First, the box rally car transmits
from the motor to the wheels a lot of torque. And secondly, the wheel is spur.
The advantage of ordinary helical gears, which are used in boxes
"civilian" cars, is contained in the fact that with the help of a longer tooth
and, in accordance with this, with a larger plane of dispersal of loads, they
it is possible to transmit the same torque at lower
volumes. In addition to all this, they work much quieter. But spur gears are used in
racing cars is not an accident: they do not make axial loads on the shafts and
increase the efficiency of the box.
Surprisingly, the racing box is not harder, but even easier.
ordinary civilian. There are actually no synchronizers here, and instead
a huge number of small teeth,
engaged when connecting the transmission on a conventional box,
huge cams are used - end projections on the gear and clutch
(there are usually 5–7 units per wheel). So that the transmissions cut in as much as possible
faster, the cams engage with more clearance across the width. Due to
of this, when connecting gears on a rally car, you can hear
distinctive iron clang.
Cam box need from
pilot the presence of a certain dexterity - especially during the downshift: for
in order to synchronize the speed of the motor and gearbox, it is necessary to filigree
operate the accelerator pedal and feel the car perfectly. During
careful driving, the pilot at the moment of transition down uses the clutch, in
during the race - namely, on machines with sequential cam
box, he practically does not need a clutch pedal. Even as a result of this, rally drivers pedal differently than ordinary drivers.
Their right leg is mediocre
lies on the gas pedal, and the left controls the clutch and brake system.
It is true to work as an accelerator significantly enough, because in the absence of
properly made regassing, downshifting or not at all
will happen, or will be accompanied by a hard blow. That is why
rally car drivers grin slyly when they ask how
need a cam box among the supporters of tuning. Still, because they appear
street racing fans who replace stock boxes with cam boxes. This
the change perfects the dynamics of acceleration, but the driver needs
maintain a constant concentration of attention when switching down, and also
the interior is filled with the roar of the work of spur gears.
This box screams
about as loud as normal
helical if there is no oil in the crankcase. You also need to take into account
significant cost of cam boxes (up to 000 per device) and short term
operation, in the end, we will come to the conclusion that the installation of the cam box on
an ordinary car is completely not justified. Naturally, the service life
car is also dependent on biased moments.
Forward-backward: excellent and bad
There is another reason why
cam boxes are not suitable for everyday roads. Although these devices
often equipped with a conventional switching search device, most
frisky and eminent boxes among racers are sequential. In rally cars
the pilot is shaking to a large extent, as a result of this, drive the lever
shifting back and forth is much more comfortable than picking up gears, as in an ordinary
square. Apart from everything else, this kinematics of the lever allows you to save a little
milliseconds on each switch.
But, riding with sequential
a cam-like box on shared roads is a terrible torture.
It turns out when we are in a traffic jam or
at right angles we turn from the main road to the secondary one, then
ordinary jump on the fly a few gears down. For example, from 5 to 2.
During a sequential box, a similar trick will not work:
come in handy with regassing methodically go to 4, 3 and only later to the second
transmission. When the driver of a rally car pushes the lever of this sequential
boxes forward or backward, at a certain angle, a special axis rotates with
multiple cams. With all this, one of the cams gives the shift fork
gears to neutral, and the other presses on another fork, and it
engages the clutch with the gear desired gear. To turn on,
say, 5th gear, you need to alternately turn the axle that is controlled several times
shift forks.
The issue of improving dynamic and speed characteristics The car has always remained a priority for designers and developers. And to improve these characteristics, it is necessary to modernize not only the engine, but also the gearbox, increasing its shift speed and the maximum allowable load on the gears. It was the cam gearbox that became the next important step in the development of racing.
Design features
The VAZ-2108 car, which first received such a gearbox, made a splash among motorists of that time. To create this checkpoint, the design of a conventional mechanical box which also surprised many. There are no synchronizers in the cam analogue, there are no small teeth on the spline couplings, instead of them there are up to seven large cams (which was the reason for the name of the unit). Also, the cams are located on the gear with which the clutch engages. Such design changes allow to reduce the duration of each switching as much as possible. A box adapted for racing races has spur gears. Due to this, the designers provided an increased coefficient useful action by reducing friction. In addition, the load on the shafts is reduced. However, their torque transmission is lower, in connection with this, it is necessary to increase their size.
Distribution gear ratios in boxes is made taking into account the use of the unit. For everyday cars, for example, VAZ-2108, the first stage is shorter, since driving performance for movement in difficult conditions. Used in racing cars, the boxes are designed with a longer first stage, which provides the necessary dynamics at the start. The switching mechanism is:
- Search. No different from switching a conventional box;
- Consistent. He's sequential. The principle of its operation is based on the possibility of shifting gears only sequentially, one up or down. It is technically more complicated, but it gives greater ease of switching.
Advantages and disadvantages
The main advantage of cam boxes is the increased speed of switching, which is three times higher than in a manual transmission. For this they were created. Based on the first advantage, the second one also occurs - the engine speed does not fall, due to which acceleration acquires additional dynamics. This is especially important for engines with a narrow operating range. In addition to the above, cam boxes have a number of advantages:
- Ability to endure increased loads;
- Less weight;
- Transmission of more torque.
The disadvantages include high cost, small resource and elevated level noise at work. Extreme conditions switching for the elements of the box, lead to wear and deformation of the cams, which take the entire load on themselves, saving the gears from damage. This leads to the need frequent replacement oil that is contaminated with metal particles.
The use of cam aggregates
The use of such boxes for non-racing cars is practically possible. However, this does not make sense if we talk about practicality. Lack of synchronizers everyday driving, requires the driver to have a completely different gearshift system. To increase the service life of the box elements, it is necessary to depress the clutch when switching, re-gas.
VAZ designers have done a great job by developing such a gearbox and bringing their invention to life. The cam box has raised the performance of racing cars to the highest level.
Not really
Optimization of engine working resources during control has occupied the minds of designers since the release of the first car. This was achieved in many ways, but one of the basic ones was to increase efficiency when interacting with the gearbox (gearbox). The very mechanics of pairing two nodes requires a certain amount of dynamic effort, but it is impossible to do without this function. One of the most energy-efficient systems for changing the torque frequency is a cam gearbox, which, however, has significant limitations in application.
Features of the device mechanism
Although cam "boxes" are superior to standard transmissions in a number of characteristics, their design can be considered as simplified relative to conventional mechanics. Main feature in terms technical device is to get rid of synchronizers. Together with them, the device of a whole group of elements was optimized, which were supposed to make the transmission control easier, but they also lengthened the period for issuing a command through several nodes. As a result, the whole infrastructure with fine teeth was replaced by a set of cam rows. At a gearbox of this type, one clutch can contain up to 7 cams, which increases the margin of the hitch area in width. At the same time, the size of the gear in this system is larger than in standard gearboxes, not to mention the replacement of the beveled shape of the teeth with a straight one. The latter was due to the need to reduce friction losses and minimize axial load on the shaft.
Operating principle
The technique of work can be sequential or search. In the first case, sequential gear shifting is implemented, and in the second - the usual one, as in a standard gearbox. In practice, it is the sequential principle that is more often used, since it allows to reflect the capabilities of the cam design to a greater extent. Switching can be carried out up and down, as well as on the sides. Control from the driver is made through a lever connected to the shaft. For example, switching a cam gearbox on a VAZ-2108 is characterized by rigidity, reliability and simplicity. The lever moves the wave-shaped grooved shaft, turning it by a certain degree. As a result, either the “neutral” or the transmission is activated. By the way, in order to further save time, the gearshift knob itself is made large and high so that the driver spends less time manipulating mechanical control. In technical terms, the semi-automatic cam systems occupy the highest stage of development, in which the driver only needs to wait required switching electronics.
Operating Capabilities
The operating torque when handling the cam shifting system is significantly reduced, which saves time. Regardless of the characteristics of the engine, the rate of change of torque in a cam gearbox is faster than in conventional transmission. The time to complete the operation is 0.4-0.6 s, which is noticeable when compared with disengaging / engaging the clutch on a car with a standard "box". More importantly, the design of sequential mechanisms expands the possibilities for tuning. This applies to cases of complete re-equipment of the car in a racing modification with foot shifting. IN this case it is necessary to install together with the gearbox pairs and the main differential pair, which can correct the dynamic qualities of the machine. Again, an ordinary driver is unlikely to need such an update, but for a connoisseur of sports tuning, it will provide a new driving quality.
The use of cam gearbox models
On cars designed for roads common use, such mechanisms are rarely used. For such provision, there must be certain grounds associated with an increase in dynamics or a simplification of the structural base of the transmission unit. Often, cam gearboxes are used in single tuning events to demonstrate certain capabilities. conceptual models. In the case of the Japanese sports car Mitsubishi Lancer evolution the combination of a sequential “box” and a 420 hp engine, in particular, made it possible to accelerate to 100 km / h in 3.5 s.
Gearbox cam mechanism on VAZ
In Russia, the production of components for transmission cam units is carried out by the Lada Special Transmission plant. This group produces sequential mechanisms suitable for VAZ cars. According to users, domestic products demonstrate high stability, clarity of operation and reliability. But you can also turn to solutions from Eastern European manufacturers like TST and Dogbox. In the lines of these companies, you can find the closest sequential gearboxes on the VAZ. Cam mechanisms foreign production usually shipped loose. For example, kits without mounting hardware are often offered, which makes it necessary to additionally look for accessories for fixing the unit to the carrier base. Sometimes automatic transmissions are taken as donor kits.
Cam gearboxes for the "classic"
Of course domestic cars the needs for equipping with cam "boxes" are not limited. Classic sedans and hatchbacks that are used on public roads, can be converted to the sequential principle of gear shifting. For this use special modifications cam gearboxes for VAZ and "classics" in one configuration or another. As a rule, these are mechanisms with a cam clutch and gear units with 5-7 elements on the surface. The more cams, the higher the resource of the unit in a pair of clutch-gear. On the other hand, the complexity of the design increases the price and complicates the integration process of the device. And even if the basis of the product fits into the mounting base in terms of parameters, then additional difficulties can be caused by the refinement of the gear shift fork. Often, for these purposes, regular fixtures, which are finalized by welding or milling. Ready-made "boxes" assemblies may well be used, but this mainly applies to obsolete 5-cam mechanisms.
Cam "boxes" and racing mechanics
Yet the target niche for the use of cam gears are sports cars. An example of a sports car from Mitsubishi has already been given, and the use of this unit in cars is not limited to this. This practice continues Subaru Impreza, provided with a sequential "box". And with regard to this model, it is worth noting the differences in approaches to completing the cam unit. IN civilian versions The sports car applies precisely the consistent principle of changing torque. But in the rally modification, this decision is prohibited, so the basic search switching mechanism is left. A striking example of the use of this design is the cam row of the Toyota MR2 gearbox. This is a two-seater sports car, the latest modifications of which received a five-speed sequential “box” SMT. The features of this node include the fact that it is able to withstand loads from engines with a power of about 800 hp.
Restrictions on the use of sequential checkpoints
Even if we discard the fact that only drivers with the appropriate experience in the physical control of the transmission can handle the cam "boxes", there are several fundamentally important kinematic nuances in the operation of such devices. Sequential shifting reduces the vehicle's maneuverability when performing complex lane changes on public roads. In other words, even a nimble racing driver will have a big loss when shifting the forks due to the need for re-gassing with sharp transitions from lower to upper stages. On a straight track, where you need to constantly and confidently maintain a high speed limit, the cam gearbox manifests itself with best sides, however, in civil car its advantages turn into disadvantages.
Conclusion
The concept of sequential gear shifting, with all its features, retains the prospects for technological development. This is confirmed by the active merging of such transmission mechanisms with electronics. For example, today there are cam units operating on the commands of the Motec programming computer. One of the main functions electronic block in a car with such a filling, as the developers say, there will be automatic control the operation of the ignition system and the performance of regassing.
