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29-411: A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor , while the clutch's output shaft is connected to the mechanism that does the work . In a motor vehicle , the clutch acts as a mechanical linkage between the engine and transmission . By disengaging the clutch, the engine speed (RPM)
58-444: A machine which produces power to a machine which absorbs power. They are mainly classified into two types. The material used for ordinary shafts is mild steel . When high strength is required, an alloy steel such as nickel , nickel-chromium or chromium-vanadium steel is used. Shafts are generally formed by hot rolling and finished to size by cold drawing or turning and grinding . Source: The standard lengths of
87-484: A common material being an organic compound resin with a copper wire facing or a ceramic material. In an automatic transmission , the role of the clutch is performed by a torque converter . However, the transmission itself often includes internal clutches, such as a lock-up clutch to prevent slippage of the torque converter, in order to reduce the energy loss through the transmission and therefore improve fuel economy. Older belt-driven engine cooling fans often use
116-516: A composite paper material. A centrifugal clutch automatically engages as the speed of the input shaft increases and disengages as the input shaft speed decreases. Applications include small motorcycles , motor scooters , chainsaws , and some older automobiles . A cone clutch is similar to dry friction plate clutch, except the friction material is applied to the outside of a conical shaped object. This conical shape allows wedging action to occur during engagement. A common application for cone clutches
145-410: A fixed fraction of a revolution per operation. Fast action friction clutches replaced dog clutches in some applications, eliminating the problem of impact loading on the dogs every time the clutch engaged. In addition to their use in heavy manufacturing equipment, single-revolution clutches were applied to numerous small machines. In tabulating machines , for example, pressing the operate key would trip
174-447: A heat-activated clutch, in the form of a bimetallic strip . When the temperature is low, the spring winds and closes the valve, which lets the fan spin at about 20% to 30% of the crankshaft speed. As the temperature of the spring rises, it unwinds and opens the valve, allowing fluid past the valve, making the fan spin at about 60% to 90% of crankshaft speed. A vehicle's air-conditioning compressor often uses magnetic clutches to engage
203-407: A lever mechanism. The majority of automotive clutches on manual transmissions are dry clutches. Slippage of a friction clutch (where the clutch is partially engaged but the shafts are rotating at different speeds) is sometimes required, such as when a motor vehicle accelerates from a standstill; however the slippage should be minimised to avoid increased wear rates. In a pull-type clutch, pressing
232-421: A single revolution clutch to process the most recently entered number. In typesetting machines , pressing any key selected a particular character and also engaged a single rotation clutch to cycle the mechanism to typeset that character. Similarly, in teleprinters , the receipt of each character tripped a single-revolution clutch to operate one cycle of the print mechanism. In 1928, Frederick G. Creed developed
261-419: A single-turn wrap spring clutch that was particularly well suited to the repetitive start-stop action required in teleprinters . In 1942, two employees of Pitney Bowes Postage Meter Company developed an improved single turn spring clutch. In these clutches, a coil spring is wrapped around the driven shaft and held in an expanded configuration by the trip lever. When tripped, the spring rapidly contracts around
290-508: Is acceptable and the inertia of the system is small. Dog clutches are used inside constant-mesh manual transmissions to lock different gears to the rotating input and output shafts. A synchromesh arrangement ensures smooth engagement by matching the shaft speeds before the dog clutch is allowed to engage. Racecar , motorcycle , and large truck transmissions, having less need for smooth engagement than passenger cars and higher performance demands, commonly employ dog clutches alone (without
319-433: Is no longer determined by the speed of the driven wheels. Another example of clutch usage is in electric drills . The clutch's input shaft is driven by a motor and the output shaft is connected to the drill bit (via several intermediate components). The clutch allows the drill bit to either spin at the same speed as the motor (clutch engaged), spin at a lower speed than the motor (clutch slipping) or remain stationary while
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#1732782781021348-411: Is the synchronizer ring in a manual transmission. A dog clutch is a non-slip design of clutch which is used in non-synchronous transmissions . The single-revolution clutch was developed in the 19th century to power machinery such as shears or presses where a single pull of the operating lever or (later) press of a button would trip the mechanism, engaging the clutch between the power source and
377-411: Is usually mounted directly to the face of the engine's flywheel , as this already provides a convenient large-diameter steel disk that can act as one driving plate of the clutch. Some racing clutches use small multi-plate disk packs that are not part of the flywheel. Both clutch and flywheel are enclosed in a conical bellhousing for the gearbox. The friction material used for the clutch disk varies, with
406-501: The Teletype Model 28 and its successors, using the same design principles. IBM Selectric typewriters also used them. These are typically disc-shaped assemblies mounted on the driven shaft. Inside the hollow disc-shaped drive drum are two or three freely floating pawls arranged so that when the clutch is tripped, the pawls spring outward much like the shoes in a drum brake . When engaged, the load torque on each pawl transfers to
435-550: The clutch are designed such that one will push the other, causing both to rotate at the same speed and will never slip. In engineering, a "dog" is a tool or device used to lock two components in relation to each other. Dog clutches are used where slip is undesirable and/or the clutch is not used to control torque . Without slippage, dog clutches are not affected by wear in the same way that friction clutches are, but result in shock when shafts of different speeds are engaged. For this reason they are best used when sudden starting action
464-455: The clutch. This can provide smoother engagement and a longer lifespan of the clutch, however wet clutches can have a lower efficiency due to some energy being transferred to the oil. Since the surfaces of a wet clutch can be slippery (as with a motorcycle clutch bathed in engine oil), stacking multiple clutch discs can compensate for the lower coefficient of friction and so eliminate slippage under power when fully engaged. Wet clutches often use
493-414: The compressor as required. Motorcycles typically employ a wet clutch with the clutch riding in the same oil as the transmission. These clutches are usually made up of a stack of alternating friction plates and steel plates. The friction plates have lugs on their outer diameters that lock them into a basket that is turned by the crankshaft. The steel plates have lugs on their inner diameters that lock them to
522-475: The default state is for the transmission to be connected to the engine. A "neutral" gear position is provided, so that the clutch pedal can be released with the vehicle remaining stationary. The clutch is required for standing starts and in vehicles whose transmissions lack synchronising means, is used to assist in matching the speeds of the engine and transmission during gear changes to avoid gear “crashing,” which can cause serious damage to gear teeth. The clutch
551-440: The machine's crankshaft for exactly one revolution before disengaging the clutch. When the clutch is disengaged, the driven member is stationary. Early designs were typically dog clutches with a cam on the driven member used to disengage the dogs at the appropriate point. Greatly simplified single-revolution clutches were developed in the 20th century, requiring much smaller operating forces and in some variations, allowing for
580-421: The motor is spinning (clutch disengaged). A dry clutch uses dry friction to transfer power from the input shaft to the output shaft, for example a friction disk presses against a car engine's flywheel by a spring mechanism. The wheels of the vehicle only rotate when the flywheel is in contact with the friction disk. To stop the transfer of power, the friction disk is moved away from the flywheel by means of
609-407: The others to keep them engaged. These clutches do not slip once locked up, and they engage very quickly, on the order of milliseconds. A trip projection extends out from the assembly. If the trip lever engaged this projection, the clutch was disengaged. When the trip lever releases this projection, internal springs and friction engage the clutch. The clutch then rotates one or more turns, stopping when
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#1732782781021638-402: The pedal pulls the release bearing to disengage the clutch. In a push-type clutch, pressing the pedal pushes the release bearing to disengage the clutch. A multi-plate clutch consists of several friction plates arranged concentrically. In some cases, it is used instead of a larger diameter clutch. Drag racing cars use multi-plate clutches to control the rate of power transfer to the wheels as
667-568: The power shaft engaging the clutch. At the end of one revolution, if the trip lever has been reset, it catches the end of the spring (or a pawl attached to it), and the angular momentum of the driven member releases the tension on the spring. These clutches have long operating lives—many have performed tens and perhaps hundreds of millions of cycles without the need of maintenance other than occasional lubrication. Cascaded-pawl single-revolution clutches superseded wrap-spring single-revolution clutches in page printers, such as teleprinters , including
696-412: The rider to shift gears or coast. Racing motorcycles often use slipper clutches to eliminate the effects of engine braking , which, being applied only to the rear wheel, can cause instability. Shaft (mechanical engineering) In mechanical engineering , a shaft is a rotating machine element , usually circular in cross section, which is used to transmit power from one part to another, or from
725-416: The shafts are 5 m, 6 m and 7 m. Usually 1m to 5m is used. The following stresses are induced in the shafts. Dog clutch A dog clutch (also known as a dog box , dog gears , dog ring , clutch dog , or positive clutch ) is a type of clutch that couples two rotating shafts or other rotating components by engagement of interlocking teeth or dogs rather than by friction . The two parts of
754-414: The transmission input shaft. A set of coil springs or a diaphragm spring plate force the plates together when the clutch is engaged. On motorcycles the clutch is operated by a hand lever on the left handlebar. No pressure on the lever means that the clutch plates are engaged (driving), while pulling the lever back towards the rider disengages the clutch plates through cable or hydraulic actuation, allowing
783-407: The trip lever again engages the trip projection. Most cars and trucks with a manual transmission use a dry clutch, which is operated by the driver using the left-most pedal. The motion of the pedal is transferred to the clutch using mechanical linkage, hydraulics (master and slave cylinders) or a cable. The clutch is only disengaged at times when the driver is pressing on the clutch pedal, therefore
812-454: The use of synchronizers) to engage gears due to their high strength and durability and low complexity and weight. These unsynchronized gearboxes, also referred to as a dog boxes, allow clutchless shifting. Oftentimes boats with inboard engines, such as sailboats, will use a dog clutch to engage the drive shaft to the transmission. Shifting from neutral to forward or reverse often results in a large "clunk" noise that can be heard by occupants as
841-425: The vehicle accelerates from a standing start. Some clutch disks include springs designed to change the natural frequency of the clutch disc, in order to reduce NVH within the vehicle. Also, some clutches for manual transmission cars use a clutch delay valve to avoid abrupt engagements of the clutch. In a wet clutch , the friction material sits in an oil bath (or has flow-through oil) which cools and lubricates
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