Manual transmissions , also known as manual gearbox , standard or colloquial transmission in some countries (eg United States) as stick shift is the type of transmission used in motor vehicle applications. It uses a clutch operated by the driver involved and released by the foot pedal (car) or the hand lever (motorcycle), to adjust the torque transfer from machine to transmission; and gear selector operated by hand (car) or by foot (motorcycle).
Conventional 5-speed manual transmission is often standard equipment in basic model vehicles, while more expensive manual vehicles are usually equipped with 6-speed transmission instead; Other options include automatic transmissions such as automatic transmission (planetary hydraulics) (often manumatic), semi-automatic transmission, or continuously variable transmission (CVT). The number of advanced gear ratios is often expressed for automatic transmissions as well (eg, 9-speed automatic).
Video Manual transmission
Ikhtisar
Manual transmissions often feature driver-driven couplings and moving tooth sticks. Most manual transmission cars allow the driver to choose the ratio of the forward gear ("tooth") at any time, but some, as is commonly installed on motorcycles and some types of racing cars, only allow the driver to choose a higher or the next lower gear. This type of transmission is sometimes called a sequential manual transmission.
In manual transmission, the flywheel is attached to the engine shaft and spins along with it. The clutch disk is between the pressure plate and the flywheel, and is held against the flywheel under pressure from the pressure plate. When the engine is running and the clutch is connected (ie, clutch pedal to the top), the flywheel rotates the clutch plate and hence the transmission. When the clutch pedal is pressed, the throw pad is activated, causing the pressure plate to stop pressing the pressure on the clutch disc. This makes the clutch plate stop receiving power from the engine, so the gears can be shifted without damaging the transmission. When the clutch pedal is released, the throw pad is deactivated, and the clutch disc is once again held against the flywheel, allowing it to start receiving power from the engine.
Manual transmission is characterized by a selectable gear ratio by locking the selected gear pair into the output shaft within the transmission. In contrast, most automatic transmissions feature epicyclic gearing (planetary) which is controlled by brake band and/or clutch package to select gear ratio. Automatic transmission that allows the driver to manually select the current gear is called manumi. Manually operated manual-style transmissions are often called automatic transmissions rather than automatic , although there is no difference between the two terms that need to be made.
Contemporary car manual transmissions typically use four to six advanced gear ratios and one reverse gear, although the user's manual car transmissions have been built with at least two and as many as seven gears. Transmissions for large trucks and other heavy equipment typically have 8 to 25 gears so the transmission can offer a wide gear range and close gear ratio to keep the engine running in the electrical tape. The same transmission operation often uses the same shifter pattern with one or more switches to involve a sequence of subsequent gear selections.
Maps Manual transmission
Transmission is out of sync
French inventors Louis-Rene Panhard and Emile Levassor are credited with the development of the first modern manual transmission. They showed their three-speed transmission in 1894 and the basic design is still the starting point for contemporary manual transmission. This type of transmission offers several gear ratios and, in most cases, is reversed. The gear is usually used by sliding it on its axis (therefore the expression of the shifting gear ), which requires careful timing and throttle manipulation as it shifts, so that the gear will rotate at approximately the same speed when involved; otherwise, the teeth will refuse to hook. This transmission is called a sliding transmission or sometimes a jam box, because of the difficulty in changing gears and rustling sounds that are often accompanied. More recent manual transmission of the four wheeled vehicles has all jagged gears at all times and is referred to as a constant-mesh transmission, with "synchro-mesh" being a further refinement of the constant mesh principle.
In both types, certain gear combinations can only be involved when two parts to engage (either gears or couplings) are at the same speed. To switch to a higher gear, the transmission is placed in a neutral position and the engine is left to slow down until the transmission parts for the next gear are at the correct speed to engage. Vehicles also slow down when in a neutral state and slow down other parts of transmission, so time in neutral depends on the level, wind, and other factors. To switch to a lower gear, the transmission is inserted into neutral and the throttle is used to speed up the engine and thus the relevant transmission part, to match the speed to pull the next lower gear. For both upshifts and downshifts, the clutch is released (moved) when neutral. Some drivers use clutch just to start from stop, and shift is done without clutch. Other drivers will press (release) the clutch, shift to neutral, then use the clutch briefly to force the transmission part to match the speed of the engine, then pressing the clutch again to switch to the next gear, a process called double clutch. Double couplings are easier to get smooth, because the speed is close but not quite suitable to accelerate or slow down only the transmission part, whereas with the coupling attached to the engine, the speed is not appropriate is against rotational inertia and engine power.
Although the transmission of light cars and trucks is now virtually universally synchronized, transmission for large trucks and engines, motorcycles, and for special racing is usually not. Unsynchronized transmission design is used for several reasons. Friction materials, such as brass, in synchronization are more susceptible to wear and breakage than gears, forged steel, and the simplicity of mechanisms increases reliability and reduces costs. In addition, the non-synchromesh transmission transmission process is slower than the synchromesh transmission shift. For production-based transmission racing, sometimes half the teeth on a dog's grip are removed to accelerate the shifting process, at the expense of greater wear.
Heavy duty trucks often use non-synchronized transmissions, although military trucks typically have synchronized transmissions, allowing untrained personnel to operate them in an emergency. In the United States, traffic safety rules refer to non-synchronous transmissions in the larger commercial vehicle class. In Europe, heavy duty trucks use synchronized gearboxes as standard.
Similarly, most modern motorcycles use an asynchronous transmission: lower gear initials and higher strengths mean that forcing the gear to change the speed is not destructive, and pedals are operated selectors on modern motorcycles, without a neutral position between gears (except, generally , 1 and 2), is not conducive to having a long shift time from the synchronized gearbox. On a 1-N-2 (-3-4...) bike, you need to stop, slow down, or synchronize the gear speed by turning off the throttle when shifting from 2 to 1.
Syncronized transmission
Most modern manual transmission vehicles are equipped with synchronized gear boxes. The transmission gear is always in the net and rotates, but the gears on one shaft can be freely rotated or locked on the shaft. The dental locking mechanism consists of a collar (or dog collar ) on a shaft that can shift sideways so that the teeth (or dog ) on the bridge of its inner surface are two circular rings with teeth in the circumference beyond them: one attached to the tooth, one to the hub shaft. When the rings are bridged by the collar, the particular tooth is rotationalally locked to the shaft and determines the transmission output speed. The gear lever manipulates the collar using a set of relationships, so arranged in such a way that a collar may be allowed to lock only one tooth at a time; when "teeth shift", the locking collar of one tooth is released before the other is involved. One collar often works for two gears; glide in one direction select one transmission speed, in the other direction choose another.
In a synchromesh gearbox, to properly fit the gear speed to the shaft as the collar-engined gear initially applies the power to the cone-shaped brass clutch attached to the gear, which brings the speed to match before locking the collar into place. Collar is prevented from bridging the locking ring when the speed does not match the synchro ring (also called blocker rings or baulk rings). The synchro ring spins a bit because of the frictional torque of the cone clutch. In this position, the dog grip can not be used. The brass coupling ring gradually causes the parts to rotate at the same rate. As they rotate at the same speed, there is no torque from the cone clutch and the dog clutch is allowed to fall into the engagement. In a modern gearbox, the action of all these components is so smooth and fast that it is hardly noticed.
The modern cone system was developed by Porsche and was introduced in 1952 Porsche 356; cone sinkoer is called Porsche-type for years after this. In the early 1950s, only a second-third shift was synchromesh in most vehicles, requiring only one synchronization and a simple relationship; The driver's guide in the vehicle suggests that if the driver needs to switch from second to first, it is best to stop completely and then switch to first and start again. With the sophistication of continuous mechanical development, synchronous transmission is complete with three speeds, then four, and then five, becoming universal in the 1980s. Many modern manual transmission vehicles, especially sports cars, now offer six speeds. Porsche 911 2012 offers a seven-speed manual transmission, with the seventh gear intended for sailing - the highest speed achieved in the sixth.
Backward teeth are usually not synchromesh, as there is only one reverse gear in a normal automotive transmission and switching the gear backwards while removal is not needed - and often very undesirable, especially at high forward speeds. In addition, the usual method of providing reverse, with the idler gear sliding into place to bridge what would be two unmatched front gears, always similar to the operation of the crash box. Among the vehicles that have synchromesh in reverse are Ford Contour in 1995-2000 and Mercury Mystique, '00 -'05 Chevrolet Cavalier, Mercedes 190 2.3-16, V6 equipped with Alfa Romeo GTV/Spider (916), certain Chrysler, Jeep, and GM products that use the New Venture NV3500 and NV3550 units, Ford Sierra Europe and Granada/Scorpio are equipped with MT75 gearboxes, Volvo 850, and almost all Lamborghini, Honda and BMW.
Internal
Shafts
Like other transmissions, the manual transmission has multiple shafts with various gears and other components that accompany it. Typically, the rear-wheel-drive transmission has three axes: input shaft, connecting shaft and output shaft. Air rifles are sometimes called layshaft .
In rear-wheel-drive transmissions, input and output shafts are located along the same line, and may actually be combined into a single axis in the transmission. This single shaft is called mainshaft . The input and output ends of this combined shaft rotate independently, at different velocities, which may be due to one slice of the slide into a hole in another, where it is supported by a pad. Sometimes the term mainshaft refers only to the input shaft or only the output shaft, rather than the entire assembly.
In many transmissions, the input and output components of the mainshaft can be locked together to create a 1: 1 gear ratio, which causes the power flow to bypass the drive shaft. Mainshaft then behaves like one, solid shaft: a situation called as a direct propulsion .
Even in transmissions that do not have direct drives, this is an advantage for inputs and outputs to lie along the same line, as this reduces the amount of torque that the transmission case must bear.
Under one possible design, the transmission input shaft has only one pinion gear, which drives the drive shaft. As long as the gear shaft is installed in various sizes, which rotates when the input shaft rotates. These gears fit the speed of forward and backward. Each gear forward on the driving shaft is permanently connected to the corresponding gear of the output shaft. However, this driven gear is not fixed rigidly to the output shaft: although the shaft runs through it, they rotate independently of it, which is made possible by pads in their hubs. Reverse is usually performed differently; see the section on Reverse.
Most front-wheel-drive transmissions for cross-machine installations are designed differently. For one thing, they have an integral drive and final differential. For others, they usually have only two axes; input and countershaft, sometimes called input and output. The input shaft runs the entire length of the gearbox, and there is no separate input pinion. At the end of the second axle (counter/output) is a pinion gear paired with a ring gear on a differential.
Front-wheel and rear-wheel-drive transmissions operate the same. When the transmission is inserted into the neutral and the clutch is released, the input shaft, clutch disk and drive shaft can continue to rotate under their own inertia. Under these circumstances, the engine, input shaft and coupling, and the output shaft rotate independently.
Dog clutch
Among the various types of clutches, the clutch dog provides a non-slip clutch of two rotating members. Not at all suitable for an intentional slip, in contrast to friction claws operated by the foot of a manual transmission vehicle.
The gear selector does not involve or disconnect the actual gearbox that is permanently connected. Instead, the action of the gear selector is to lock one of the spinning gears to the shaft that runs through its hub. The trunk then spins along with the gears. The speed of the output shaft relative to the driving shaft is determined by the ratio of the two gears: which are permanently attached to the driving shaft, and the gear pair is now locked on the output shaft.
Locking the output shaft with gears is achieved by using the dog clutch selector. The dog clutch is a sliding selector mechanism aligned with the output shaft, which means that its hub has a tooth that enters the slot (splines) on the shaft, forcing the shaft to rotate with it. However, splines allow the selector to move back and forth on the shaft, which occurs when driven by a selector fork connected to the gear lever. The fork does not rotate, so it attaches to the collar pads on the selector. The selector is usually symmetrical: it slides between two gears and has synchromesh and gear on each side to lock one gear to the shaft.
Synchromesh
Synchromesh transmission was introduced by Cadillac in 1928. If the dog's teeth come into contact with the gears, but the two parts rotate at different speeds, the teeth will fail to move and a loud grinding sound will be heard as they unite. For this reason, the modern dog clutch in the car has a synchronization mechanism or synchromesh , which consists of a cone clutch and a blocking ring. Before the teeth can be used, the conical cone moves first, which brings the selector and gear to the same speed using friction. Until synchronization occurs, the tooth is prevented from making contact, as the further movement of the voter is prevented by the blocker ring (or baulk). When synchronization occurs, friction on the ring blocker will decrease and winding slightly, thus forming a particular groove or curve that allows the further path of the voter that brings teeth. The exact design of synchronization varies among manufacturers.
The synchronizer must overcome the momentum of the entire input shaft and clutch disc while changing the piston rpm to adjust the new gear ratio. It can be misused by exposure to momentum and engine power, which occurs when attempts are made to select the gear without letting go of the clutch completely. This causes extra wear and tear on the rings and arms, reducing the service life. When an experimental driver tries to "match the revs" on a synchronized transmission and force it into the tooth without using a clutch, the synchronization will make up for the difference in RPM. Success in using a gear without grasping can fool the driver into thinking that the RPM of the layshaft and transmission is exactly the same. Nevertheless, the rev estimates. matching by grasping can reduce the difference in rotational speed between layshaft and transmission gear shaft, thus reducing synchronous wear.
The sync ring is made of metal and can be fitted with an anti-wear coating called a friction layer. Common metals for synchronization rings are brass and steel. Coatings usually consist of molybdenum, iron, bronze or carbon. The synchronization ring is produced either with a large formation (general forging) or sheet metal formation. The latter involves stamping off an empty sheet of metal sheet and subsequent machining with an advanced composite tool or transfer tool. A friction layer usually consists of molybdenum which is sprayed hot. Alternatively, a friction layer of iron or bronze sinter may be used. Carbon-coated synchronizer rings are very wear resistant and offer excellent frictional behavior. Because the price is higher, it is provided for high-performance transmissions.
Transmission with brass component synchronization is generally not suitable for use with oil specifications GL-5 unless otherwise specified by the manufacturer as an extreme pressure additive (EP) in oil corrosive to brass and bronze components at high temperatures and lowers the effectiveness of synchronizers at low temperatures. Additives in GL-5 oil also cause physical damage to brass adapters because the EP additive strongly binds the brass rather than brass on itself, causing a small layer of brass to wear off with every tooth replacement. Instead, oils that meet only the GL-4 specification should be used as much as possible.
Flip
Previous discussions usually only apply to forward gear. Implementation of reverse gear is usually different, implemented in the following way to reduce transmission costs. Reverse is also a pair of gears: one gear on the driving shaft and one on the output shaft. However, while all front teeth are always put together, there is a gap between the reverse gear. In addition, both are attached to the axis: no one is spinning freely about the shaft. When the retreat is selected a small tooth, called idler gear or idler slower , slid between them. The idlers have teeth that are attached to both gears, and thus the pair of teeth merges and reverses the direction of rotation without changing the gear ratio.
In other words, when the reverse gear is selected, it is actually the gear that is being connected, without the aid of a synchronization mechanism. For this reason, the output shaft should not rotate when the reverse is selected: the vehicle must be stopped. In order for the reverse to be selected without grinding even if the input shaft is spinning inertia, there may be a mechanism to stop the input shaft from the spinning. The driver brought the vehicle to a halt, and chose to retreat. When the selection is made, some mechanisms in the transmission stop the input shaft. Both gears stop and the idler can be inserted between the two. There is a clear description of such a mechanism in the 1996-1998 Honda Civic Service Manual, which calls it a "noise reduction system":
Each time the clutch pedal is pressed to shift backward, the main axle keeps spinning due to its inertia. The difference in velocity produced between the mainshaft and the inverted lethal teeth produces a dental disorder [grinding]. The inverted dental noise reduction system uses cam plates that are added to the inverted shift holders. As it shifts backward, the 5th/reverse shift piece, connected to the shift lever, rotates the cam plate. This causes the 5th synchro set to stop the rotating mainshaft.
Reverse teeth that are implemented in this way produce a loud whine, which is not usually heard in the front teeth. Teeth on the front teeth of most consumer cars are cut in a helical manner. As the helical gears rotate, there is constant contact between the gears, which results in a quiet operation. Although all front teeth are always connected, they do not make sounds that can be easily heard above the sound of the engine. In contrast, most of the reverse gear is the pacemaker, which means that the teeth are straight, to allow sliding engagement of the slacker, which is difficult to do with helical gears. Dental teeth spur united as the gears rotate, producing a distinctive whimper.
Seeking to retreat as the vehicle moves forward causes severe gear wear (except in transmission with synchromesh on reverse gear). However, most manual transmissions have gates that lock in reverse directly from the 5th gear to help prevent this. To reverse from the 5th, the shift lever must be moved to the middle position between 3 and 4, then back up and back. Another widespread solution puts a retreat to the left of tooth 1 instead of behind the 5th (where one might expect to find 6th gear). Many of the newer six-speed manual transmissions have collars under the shift key that must be lifted to perform a reverse. Other locking designs include having to push the shift lever inward, toward the floor, to allow for inverse engagement, or require the driver to exert additional force to move the shift lever in the opposite direction.
The dental design of the reverse gear represents some compromise (less robust, unynchronized engagement and loud noise) that is acceptable due to the relatively small amount of driving that occurs in reverse. The classic SAAB 900 gearbox is an example of a well-known gearbox with helical back teeth involved in the same non-synchronized way as the pacemaker described above. The design allows reverse to share wheels with first gear, and is very quiet, but produces difficult engagement and unreliable operation. However, many modern transmissions now include retrograde and helical drive alignment, especially in applications that use three axes as part of a transmission implementation rather than a conventional dual input and output shaft (usually to allow a shorter gearbox for the number of gears supplied) because the third axle inherently gives the option to reverse the output rotation while still allowing the permanent meshing gear.
Design variation
Ratio calculation
Until the mid-1950s (previously in Europe and later in the US, on average) vehicles were generally equipped with 3-speed transmissions as standard equipment. The 4-speed unit began to appear on volume production models in the 1930s (Europe) and 1950s (US) and gained popularity in the 1960s; some exotics have 5 speeds. In the 1970s, as fuel prices rose and fuel economy became an important sales feature, a 4-speed transmission with an overdrive or 5-speed gear was offered in a mass market car and even a compact pickup truck, pioneered by Toyota ( who advertise the facts by giving each model a suffix SR5 while gaining the fifth speed). 6-speed transmission began to emerge in high-performance vehicles in the early 1990s. The 7-speed transmission appears on extreme high-end supercars, such as the Bugatti Veyron 2005 (semi-automatic manual transmission). In 2012, the Porsche 911 features a 7-speed manual transmission, being the first of its class to support this feature, paving the way for the 2014 Chevrolet Corvette Stingray.
Currently, the mass-market automotive mass manual transmission is almost entirely 5-speed. The 4-speed manual transmission has fallen to almost total unused in the late 1980s, having gradually become less common in vehicles during the 1980s. In the early 1990s in the United States, they were usually found only in vehicles with engines of about 1-2 liters.
It has been widely anticipated that for electric vehicles (EVs), clutches and multi-speed gearboxes will not be necessary, since electric motors can propel vehicles forward and back from zero speed and typically operate over a wider speed range than a combustion engine. Gearbox removal represents a significant reduction in powertrain weight and complexity, and also eliminates the source of important parasitic losses. The majority of first generation consumer EVs have a single speed. However, the current trend suggests that the multi-speed gearbox is likely to return for much of the future EV. This allows the use of smaller lower torque motors running at higher speeds to achieve greater torque on the wheels for low-speed traction effort, and higher upper road speeds. Simple efficiency gains are also possible by reducing the proportion of time that the motor operates at very low speeds where efficiency is reduced. The wider speed range of the motor means that the required number of ratios is lower than for a combustion engine vehicle, with two to four speed designs emerging as the optimum depending on the application.
Initially Tesla Roadster (2008) was intended to have a two-speed manual transmission made with purpose, but the gearbox proved problematic and then replaced with fixed ratio transmission.
Gear rate
The slowest gear (1st gear or low gear) in most automotive applications allows three to four revolutions for each output revolution (3: 1). High, or "top", the gear in many three or four speed manual transmissions previously locks the output shaft to rotate at the same speed as the engine (1: 1). Five and six speed gearboxes are almost always 'overdrive' in the upper gear with engine rotation of less than full rotation for each output shaft revolution, 0.8: 1 for example (however, final drive, or differential, always has a further reduction gearing).
Extras overdrive
In the 1950s, 1960s, and 1970s, roaming lowway fuel-efficient with low engine speeds was in some cases enabled on vehicles equipped with 3 or 4 speed transmissions via a separate overdrive unit inside or behind the rear housing housing.. It is manually moved while in high gear by throwing a button or pressing a button on the gear knob or on the steering column, or automatically by momentarily lifting the foot from the accelerator with a vehicle traveling over a certain speed of road. Overdrives are automatically released by the floor accelerator, and lock control is provided to allow the driver to disable overdrive and operate the transmission as a normal (non-overdrive) transmission.
Shaft and tooth configuration
In conventional rear-drive transmission, there are three basic axes; input, output, and drive shaft. Input and output are together called mainshaft , because they are joined in the transmission so that they look like a single axis, even though they are totally independent of each other. The input length of this shaft is much shorter than the output shaft. Parallel to the main axis is the driving shaft. There are a number of gears mounted along the drive shaft, and a suitable gear along the output shaft, although this is not fixed, and rotates independently of the output shaft. There is a sliding dog collar, or a dog grip, between the gear in the output shaft, and to attach the tooth to the shaft, the collar glides into the space between the shaft and the inner spaces of the gear, thus rotating shaft as well. One collar is usually mounted between two gears, and slid in two ways to pull one or another gear, so at four speeds there will be two collars. Front-drive transmissions are essentially the same, but can be simplified. There are often two axes, inputs and outputs, but depending on the direction of engine rotation, three may be required. Instead of the input shaft that drives the countershaft with the pinion gear, the input shaft takes over the driving shaft work, and the output shaft runs parallel to it. The gears are positioned and engaged as in the driving shaft and output shaft of the rear drive. This only removes one main component, pinion gear. Part of the reason that inputs and outputs in-line on the rear drive unit is to relieve torsional stress on transmission and buffering, but this is not a problem in the front-drive because the gearbox is integrated into the transaxle.
The basic process is not universal. Fixed and free teeth can be mounted on the input or output shaft, or both.
Shifter distribution is also a design issue; it does not have to be the case that all the teeth rotate freely with the selector in one axis, and the permanent gear on the other. For example a five-speed transmission may have a first-to-second picker on the driving shaft, but the third to fourth picker and the fifth selector on the main shaft, which is a configuration in the Honda Civic 1998. This means that when the vehicle stops and neutral moves with the coupling attached and the spinning input shaft, the third, fourth, and fifth gear pairs are not rotating.
In some transmission designs (Volvo 850 and V/S70 series, for example) there are actually two countershafts, both of which drive the meshing pinion with the front-wheel-drive transaxle ring gear. This allows the transmission designer to make the transmission narrower, since each drive shaft only needs to be half as long as the traditional drive shaft with four gears and two shifter.
In some exotic sports cars and racing cars equipped with dual clutch transmissions, there are usually two input shafts and two hooks, one for the odd numbered gear and one for the numbered gear. This allows the next gear to be pre-activated and selected by removing one of the input shafts which are suppressing each other. This results in no power disturbance being moved through to the output shaft.
Freewheeling
Some automotive manual transmissions have freewheeling capabilities in the 1930s until the 1960s.
Clutch
In all vehicles that use transmission (almost all modern vehicles), clutch devices are used to separate the engine and transmission when necessary. This is because most internal combustion engines have to keep running when in use, although some modern vehicles turn off the engine when the vehicle is stationary. Clutch completes this in a manual transmission. Without it, then other than when the transmission is in neutral, the engine and the wheel will always be closely connected, and every time the vehicle stops, the engine will stop. Without the clutch, changing the gear will be very difficult, even if the vehicle is already moving: not choosing the gear when transmission under load requires considerable strength (and significant damage risk), but can still be done with much less power if the driver releases a momentary accelerator before making a shift as if no clutch is released. Selecting a tooth requires a rotation of the engine speed to be held at a very precise value depending on the desired vehicle and gear speed - the speed within the transmission must match. In a 4-wheel vehicle, the clutch is usually operated by a pedal; on a motorcycle, the lever on the left handlebar serves the purpose.
- When the clutch pedal is fully depressed, the clutch is completely released, and no torque is transferred from the engine to the transmission (and with the extension to the drive wheel). In this unconnected state it is possible to select the gear or stop the vehicle without stopping the engine.
- When the clutch pedal is fully disconnected, the clutch is fully connected and all engine torque is transferred. In this state, the clutch does not slip, but acts as a rigid coupling to transmit power to the gearbox.
- Among these extreme engagements and discharges clutch slips to different levels. When it slips it still transmits torque despite the speed difference between the engine crankshaft and the transmission input. Because this torque is transmitted through friction rather than direct mechanical contact, considerable force is wasted as heat (which is squandered by clutches). Applied correctly, slip allows the vehicle to start from a standstill, and when it is moving, allows the engine rotation to gradually adjust to the newly selected gear ratio.
- Learning to use coupling efficiently requires the development of muscle memory and coordination levels.
- The highly tuned motocross or motorcycle rider can "hit" or "fan" the clutch when out of the corner to help the machine in returning to the point where it gives the most power. This can be done at a lower level, by car.
The clutch is usually released by a thrust bearing which makes contact with the pressure lids on the clutch ring plate and pushes them inside to release the clutch friction pad. Usually the pads remain pulled away from the petals and do not rotate. However, the pads can be "burned" and damaged by using the clutch pedal as a footrest, causing the bearing to rotate continuously from touching the clutch plate.
Floating shift
Floating shifts or floating gears change gears without clutch pressing, usually on non-synchronized transmissions. Because the clutch is not used, it is easy to adjust the gear speed, and the driver can quickly cause massive (and expensive) damage to the gears and transmissions. Floating shifts are often done on large trucks with standard gearboxes (not synchronized).
Type of tooth shift
Peripherals installed on the floor
In most vehicles with manual transmission, the gears are selected by manipulating the lever called gear stick , shift drive , shifting , the lever gears , tooth selectors , or shifter are connected to transmission via link or cable and mounted on the floor, dashboard, or steering column. Move the forward, backward, left, and right levers to a specific position to select a specific gear.
An example of a four-speed transmission layout is shown below. The N neutral mark, the position where no gear is activated and the engine is separated from the vehicle's drive wheel. The entire horizontal line is a neutral position, although the shifter is usually spring so it will return to the center of position N if it is not transferred to the other gear. The R mark is reversed, the gear position used to drive the vehicle backwards.
This layout is called shifting pattern . Because of quadrant shifts, the basic setting is often called the H-pattern . Shift patterns are usually printed or printed on or near the tooth knob.
Usually, the first tooth moves in the top left position with the second down, third to right with the fourth, below, and so on. The only other pattern used in manual production vehicle transmission is known as the Dog-leg gearbox pattern. This pattern is first in the lower left, second up and right with the third bottom, fourth up and right, and so on. This pattern is found primarily in race-inspired races and races. Placing the election position for second gear above the position for the third gear is desirable in the race due to the more frequent transfer from second to third rather than from first to second.
Independent of the shifting pattern, the reverse gear location may vary. Depending on the design of a particular transmission, the reverse may be located at the top left of the shift pattern, in the lower left, in the lower right, or at the top right. Often there is a mechanism that allows the reverse selection only from the neutral position, or the back locking that must be released by pressing the spring gear knob or lifting the spring collar on the sliding stick, to reduce the possibility of the driver inadvertently choosing backwards.
"Three in the tree" vs. "four on the floor"
During the period when a US vehicle typically has only three forward speeds and a steering column is the most common shifter location, this layout is sometimes called "three in a tree". In contrast, high-performance cars, and European vehicles in general, mostly use a four-speed transmission with floor-mounted shifter. This layout is then referred to as "four on the floor".
Most FR vehicles (front-engined, rear-wheel drive) have transmissions between the driver and the front passenger seat. Floor-mounted shifter is often connected directly to the transmission. FF vehicles (front-engined, front-wheel drive), RR vehicles (rear engine, rear-wheel drive) and front-engine vehicles with rear-mounted gearboxes often require mechanical connections to connect the shifter to the transmission.
shifters installed in columns
Some vehicles have a gear lever mounted on the steering column. A 3-speed column shifter, later known as "three in a tree", began to appear in America in the late 1930s and became common during the 1940s and 1950s. If a US vehicle is equipped with overdrive, it is possible to become a Borg-Warner type, operated briefly backwards from the accelerator pedal when above 28 mph (45 km/h) to activate, and momentarily coat the same pedal to return to normal gear. Controls simply disable overdrive for situations such as parking on hills or preventing unwanted shifts to gear.
Later, European and Japanese models began to have a 4-speed shifter shift with this shift pattern:
The majority of vehicles with American specifications sold in the US and Canada have 3-speed column level shifters - the first generation Chevrolet/GMC model vans of 1964-70 have an ultra-rare 4-speed column shifter. Manual shifter mounted in the column disappeared in North America in the mid-1980s, last appeared in the Chevrolet pickup truck 1987. Outside of North America, the shifter mounted in the column remained in production. All Toyota Crown and Nissan Cedric taxis in Hong Kong had a 4-speed column shift until 1999 when the first automatic transmission was offered. Since the late 1980s or early 1990s, a 5-speed column shifter has been offered in several vans sold in Asia and Europe, such as Toyota Hiace, Mitsubishi L400, and Fiat Ducato first generation.
The column shifter is mechanically similar to the floor shifter, although the shift occurs in a vertical plane rather than a horizontal. Because the shifter is further away from the transmission, and the movement on the shifter and on the transmission is on a different plane, the column shifter requires a more complicated connection than the floor transfer. The advantage of a column shifter is the ability to switch between the two most commonly used gear - second and third - without releasing the steering wheel, and the lack of interference with passenger seating space in vehicles equipped with bench seats.
Shifters installed in the console
Some smaller cars in the 1950s and 1960s, such as the 2CV CitroÃÆ'¡n, Renault 4L and the early Renault 5 had a shifter on the dashboard panel. It's cheaper to make than a column shifter and more practical, since the gearbox is mounted in front of the machine. The linkage for the shifter can be positioned on top of the machine. The disadvantage is that the shift is less convenient and usually slower to operate.
Small cars and new MPVs, such as the Suzuki MR Wagon, the Fiat Multipla, the Toyota Matrix, the Pontiac Vibe, the Chrysler RT platform car, the Honda Element, the Honda Civic and the Honda Avancier, can feature manual or automatic gear shifter transmissions located on the instrument panel, with Chryslers and Corvairs Powerglide in the mid-1950s. Shifter mounted on the console is similar to the floor-mounted shifter because most of the used in modern vehicles operates on a horizontal plane and can be mounted into vehicle transmissions in the same way as a floor-mounted shifter does. However, since the location of the gear shifter as compared to the location of the column shifter and the floor shifter, as well as the position of the shifter to the rest of the controls on the panel often requires that gear shifting be installed in a space that has little integral control with vehicle operation, or frequently used controls, stereo or HVAC systems, to help prevent accidental activation or driver confusion, especially in right-hand drive vehicles.
More and more small cars and vans from manufacturers such as Suzuki, Honda, and Volkswagen featuring console shifter as they free up space on the floor for other features such as storage compartments without requiring shift gears mounted on the steering column. In addition, the basic location of the gear shift compared to the column shifter makes the console switch easier to operate than the column shift.
Guide sequential
Some transmissions do not allow the driver to arbitrarily pick any tooth. Conversely, the driver can only choose the next lower or higher gear ratio. Sequential transmission often incorporates a less synchronous dog-clutch attachment mechanism (not a typical synchromesh dog coupling in H-pattern automotive transmissions), in which case the coupling is only necessary when selecting first or reverse gear from neutral, and most tooth changes can be done without coupling. However, consecutive redirects and sync-less attachments are not inherently linked, although they often occur together because of the environment (s) where these transmissions are used, such as race cars and motorcycles.
The sequential transmission is generally controlled by a back and forth lever, a foot pedal, or a series of paddles mounted behind the wheel. In some cases, these are mechanically connected to the transmission. In many modern examples, this control is attached to sensors that instruct the transmission computer to make a shift - many of these systems can be switched to automatic mode, where computers control time shifts, such as automatic transmissions.
In a motorcycle
Motorcycles typically use sequential transmission, although the shift patterns are slightly modified for safety reasons. In a gear motor usually shifts with the left foot pedal, the layout becomes this:
1 - N - 2 - 3 - 4 - 5 (- 6)
The pedal goes one step - both up and down - from the center, before reaching its limit and should be allowed to return to the center position. Thus, replacing multiple teeth in one direction can be done by pumping the pedal repeatedly, either up or down. Although neutrals are listed as first and second gears for this type of transmission, but "feels" more like first and second gears are just "farther" from each other than the other two sequential teeth. Since this can cause difficulties in finding neutrals for inexperienced riders, most motorcycles have a neutral indicator light on the instrument panel to help find neutral. The reason neutral actually does not have its own place in sequence is to make it move faster from first to second when it moves. Neutrals can be inadvertently shifted into, although most of the high end, new model motorcycles have the means to avoid this. The reason for having a neutral between the first and second gears than at the bottom is when it stops, the rider can click repeatedly and know that they will end up in the first position and not neutral. This allows the rider to quickly move his bike from a standstill in an emergency situation. It can also help on steep hills where required high torque. It can be harmful or even dangerous to try to be the first without realizing it, then try for a lower gear, just to get neutral.
On motorbikes used on race tracks, the shifting pattern is often reversed, that is, the rider clicks up to raise the teeth. This pattern of use improves ground clearance by placing the rider's legs on a shift lever when the rider is likely to need them, that is, when leaning in and out of tight bends.
The shifting pattern for most underbone or miniature motors with automatic centrifugal clutches is also modified for two main reasons - to allow inexperienced riders to shift gears without the problem of "finding" neutrals, and also because greater power is required. to "lift" the gear lever (because the tooth pedal of the underbone motorcycle also operates the clutch). The gear lever of the underbone has two ends. The rider clicks to the front end with his left foot up to the upper teeth and clicks on the back with heel to neutral, while the miniature still retains the one-end lever, with the rider clicking down and raising the lever upward to lower the teeth (or vice versa). Some underbone models like the Honda Wave have a "swivel" shift pattern, which means that the rider can shift directly to the neutral from the top gear, but for safety reasons this is only possible when the motorcycle is stationary. Some models also have a tooth position indicator for all gear positions on the instrument panel.
Semi-manual
Some new transmissions (Alfa Romeo's Selespeed gearbox and BMW Sequential Manual Gearbox (SMG) for example) are conventional manual transmissions with computerized control mechanisms. This transmission has teeth that can be selected independently but does not have a clutch pedal. Instead, the transmission computer controls the servo that releases the clutch when necessary.
This transmission varies from sequential transmission because it still allows non-essential shifting: the SMG system previously used by BMW, for example, can switch from 6th gear straight to 4th gear.
Early versions of this type of transmission were Autostick, used in Volkswagen Beetle and Karmann Ghia from 1967 to 1976, where the clutch was removed by the servo as the driver pushed slightly down on the gear lever. This is a 3-speed unit.
In the case of the early generation Saab 900, the 'Sensonic' option is available when the gears are shifted with a conventional shifter, but the clutch is controlled by the computer.
See semi-automatic transmission for more examples.
Short shifter
A short short shift , also known as the short throw shifter , is the result of an automotive aftermarket modification of manual transmission stick shifts either by modification of an existing shift stick or, alternately, by replacement of all parts.
The purpose of this modification is to mechanically reduce the time between tooth replacements when accelerated or slowed, thus improving the performance of the car. The modification of the existing shift stick, also known as the manual gear stick, can take two forms: either the physical shortening of the existing shift stick, known in the industry as 'cut', or bending. By reducing the length of the rod, the distance to be taken to change the gear is reduced effectively, thus reducing the time spent shifting. At the same time, the amount of force required to shift increases as the lever is shorter.
Some major vehicle manufacturers such as Subaru, Mazda, and Porsche offer short shifter as stock modifications such as Subaru WRX, Subaru WRX STI, Subaru BRZ, Mazda Miata, and as an option like in Porsche 911.
Finger shift
In Japan, finger shifts are used on buses. The system was created by Robert Bosch GmbH. Sometimes also referred to as electro-pneumatic gearboxes or finger control transmissions (FCT).
In a shift operation using a mechanical connection mechanism on the rear-engined bus, the FCT detects the position of the shift lever and converts it into an electronic signal. These signals are then used to make transmission changes using air pressure. This results in easy shift changes and reduces driver fatigue, and also reduces the weight of the link mechanism. The pseudo-reaction force is added to the operation to reduce the driver's discomfort. In addition, complicated fail-safe mechanisms are included, such as the one that prevents mis-shift, and which ensures safe driving in case of system failure. FCT is used in heavy duty MP series buses since November 1983 after basic research and several prototypes and practical tests for 10 years. It gained popularity in combination with measures to help older drivers, and in the following year, it applied to large tour buses.
Benefits
Fuel economy
The manual transmission mounts the engine into a transmission with a rigid coupling instead of a torque converter on an automatic transmission or a v-belt of continuous variable transmission, which sneaks by nature. Manual transmission also does not have the parasitic power consumption of the automatic transmission hydraulic pump. Therefore, manual transmissions generally offer better fuel savings than automatic or continuous variable transmissions; but disparity is somewhat offset by the introduction of locking torque converters on automatic transmissions. Increased fuel economy with properly operated manual transmission vehicles versus equivalent automatic transmission vehicles can range from 5% to about 15% depending on driving conditions and driving style. Lack of control over downshifting under load in automatic transmissions, coupled with greater engine engine efficiency under higher loads, may allow additional fuel addition of manual transmission by allowing operators to maintain engine performance under a more efficient load/RPM combination. This is especially true as between manual and automatic versions of old models, as more recent advances including variable valve timing reduce automatic transmission efficiency losses by enabling better performance over the broader RPM range. In recognition of this, many current models (2010 and on) come with manual mode, or overwrite the automatic model, although the level of control varies greatly by the manufacturer. Also, manual transmissions do not require active cooling and because they are mechanically much simpler than automatic transmissions, they generally weigh less than comparable automatic pistols, which can boost the economy in stop-and-go traffic. But the gap in the economy is being shut down quickly, and many models of mid-to-high-end automated vehicles are now getting better economies than their standard-spec counterparts. This is partly due to the increasing impact of computers coordinating various systems, especially in hybrid models where engine and propulsion motors must be managed, as well as using different automated technologies such as CVT and double clutch automatics.
Longevity
Because manual transmissions are mechanically simpler, easier to make, and have fewer moving parts than automatic transmissions, they require less maintenance and are easier and cheaper to repair. Due to their mechanical simplicity, they often last longer than automatic transmissions when used by skilled drivers. Normally, there are no electrical components, pumps and cooling mechanisms in a manual transmission, other than an internal switch to enable reversal lighting. These attributes become very important with vehicles trapped in mud, snow, etc. Movements back and forth from drivers of vehicles used to remove jammed vehicles can destroy automatic transmissions. Coupling is a worn item that may need to be replaced at a certain point in the vehicle's lifespan, but the life of the clutch depends on the operating conditions it wears.
Cost
The price of a new vehicle with a manual transmission tends to be lower than that of the same vehicle as the automatic transmission.
Most of the new vehicles are available with manual or automatic transmissions. Often there is a cost difference between the two. Manual transmission is generally cheaper than automatic transmission. For example, the base price of Chevrolet Cruze 2LT with manual transmission is $ 22,120, while the base price is $ 23,405 - the difference is $ 1,285.
Lubrication
Most manual transmissions rely on splash lubrication although some five-speed Rover gearboxes do incorporate an oil pump. The problem with splash lubrication is that it depends on speed. There are centrifugal effects, hydrodynamic effects and effects of gears that act as pumps. If the gearbox is equipped with a Perspex window and runs on the test rig, this effect can be observed. When the gearbox is run through its spin range, the oil jet will switch and move. Research on the Austin Maxi 1500 gearbox shows that one of the ball races runs dry at 80 miles per hour (130 km/h). The solution is to change the casting to include a small projection that will intercept the main oil jet that is present at 80 mph and disperse it. This small modification allows the Maxi 1750 gearbox to be a relatively free problem. Four speed gearboxes rarely show this problem because with their maximum speed (and maximum power) they are essentially solid shafts and the gears do not emit power.
Performance and control
Manual transmissions generally offer a wider choice of gear ratios. Many vehicles offer a 5-speed manual or 6-speed, while the automatic option will usually be 4-speed. This is generally due to the increase in available space in the manual transmission compared to the automatic, since the latter requires additional components for self-displacement, such as torque and pump converters. However, automatic transmissions now add more speed when the technology matures. ZF currently produces 7 and 8 speed automatic transmissions. ZF also plans 9 speed automatic for use on front wheel drive vehicles. Increasing the number of gears allows better use of the engine power band, which results in improved fuel economy while remaining at the most fuel-efficient parts of the power band, or higher performance, thus staying closer to peak engine power ratings. Even with more forward speed and the potential of designing more front gears to offer higher speed and/or torque, the manual transmission remains smaller and much more compact than its larger, automated cousin, as referenced by the 991 Porsche Generation 911 and C7 Chevrolet Corvette, which offers a 7-speed manual transmission.
Engine braking
Unlike most manual gearboxes, most of the automatic transmissions have much less effective engine braking. This means that the engine does not slow the vehicle effectively when the automatic transmission driver releases the engine speed control. This leads to more use of the brakes on vehicles with automatic transmissions, resulting in shorter brake life. Brakes also tend to overheat in hilly or mountainous areas, resulting in reduced braking ability, fading brakes, and the potential for total failure with automatic transmission vehicles.
Start push
Vehicles with manual transmissions can often run when the starter motor is not operating, usually because the battery is low.
Weakness
Curve of complexity and learning
For most people, there is a slight learning curve with manual transmission, which may be intimidating and unattractive for inexperienced drivers. Because the driver must develop a feeling to really pull the clutch, inexperienced riders will often turn off the engine. Most drivers can learn how to drive a vehicle with a manual transmission in just one hour, though it may take weeks before it becomes "second nature". In addition, if inexperienced drivers choose improper equipment due to errors, damage to mechanical parts and even loss of control may occur if not fixed quickly. Studying the coordination of the pedal/throttle clutch can be made easier by using the clutch pedal alone, on a flat surface. This will allow the operator to measure where the "sweet spot" of the clutch engagement is. True "release speed" of the clutch pedal ( slow for smooth, fast for abrupt) will show when and where the use of the accelerator will occur.
In many jurisdictions, such as the UK, a driving license issued only for vehicles with automatic transmissions does not apply to driving a vehicle with a manual transmission, but the license for a manual transmission covers both. This also applies to the P1 (provisional-1) car license holder in New South Wales, Australia, but the P2 (provisional-2) license holder is allowed to drive a vehicle with good transmission.
Shift speed
Automatic transmission can usually shift the ratio faster than manual toggle can be done, because the time required for the average driver to push the clutch pedal to the floor and move the gear rod from one position to another. This is especially true in terms of dual-clutch transmission, which is a computer-controlled automatic transmission that mechanically operates more like a manual transmission than a traditional automatic transmission.
Ease of use
Because manual transmissions require the operation of the extra pedals, and keep the vehicles in the right gear at all times, they need more concentration, especially in heavy traffic situations. Automatic transmission, on the other hand, requires only the driver to accelerate or slow down as needed, with the vehicle doing the job of selecting the right gear. Manual transmission also puts a greater workload on the driver in heavy traffic situations, when the driver should operate the clutch pedal quite often. Because the clutch pedal can require a large number of styles, especially on large trucks, and longer pedal trips compared to brakes or accelerators, it is necessary to move the entire foot, not just the feet near the ankle, manual transmission can cause fatigue, and more difficult for the injured person to driving. Additionally, since automatic transmissions can be pushed on just one leg, people with a missing or disturbed leg can still drive, unlike manual transmissions that require the use of two legs at a time. Similarly, manual transmissions require the driver to periodically release one hand from the wheel while the vehicle is on the move, which can be difficult or impossible safely for people with missing or disturbed arms, and requires increased coordination, even for those who have full use of both hands.
Stopping in the hills
The clutch suffers most of its wear in the first gear because moving the vehicle from a jam involves a lot of friction on the clutch. When accelerating from a silent position on the slopes, the problem is exacerbated by the number of jobs that are dipped
Source of the article : Wikipedia
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