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Layshaft
A layshaft is an intermediate shaft within a gearbox that carries gears, but does not transfer the primary drive of the gearbox either in or out of the gearbox. Layshafts are best known through their use in car gearboxes, where they were a ubiquitous part of the rear-wheel drive layout. With the shift to front-wheel drive, the use of layshafts is now rarer. The ''driving shaft'' carries the input power into the gearbox. The ''driven shaft'' is the output shaft from the gearbox. In car gearboxes with layshafts, these two shafts emerge from opposite ends of the gearbox, which is convenient for RWD cars but may be a disadvantage for other layouts. For gearboxes in general, gear clusters mounted on a layshaft may either turn freely on a fixed shaft, or may be part of a shaft that then rotates in bearings. There may be multiple separate clusters on a shared shaft and these are allowed to turn freely relative to each other. Origins The term ''layshaft'' originates with watermill mac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constant Mesh Gearbox
A manual transmission (MT), also known as manual gearbox, standard transmission (in Canada, the United Kingdom, and the United States), or stick shift (in the United States), is a multi-speed motor vehicle transmission system, where gear changes require the driver to manually select the gears by operating a gear stick and clutch (which is usually a foot pedal for cars or a hand lever for motorcycles). Early automobiles used ''sliding-mesh'' manual transmissions with up to three forward gear ratios. Since the 1950s, ''constant-mesh'' manual transmissions have become increasingly commonplace and the number of forward ratios has increased to 5-speed and 6-speed manual transmissions for current vehicles. The alternative to a manual transmission is an automatic transmission; common types of automatic transmissions are the hydraulic automatic transmission (AT), and the continuously variable transmission (CVT), whereas the automated manual transmission (AMT) and dual-clutch transmissio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchromesh
A manual transmission (MT), also known as manual gearbox, standard transmission (in Canada, the United Kingdom, and the United States), or stick shift (in the United States), is a multi-speed motor vehicle transmission system, where gear changes require the driver to manually select the gears by operating a gear stick and clutch (which is usually a foot pedal for cars or a hand lever for motorcycles). Early automobiles used ''sliding-mesh'' manual transmissions with up to three forward gear ratios. Since the 1950s, ''constant-mesh'' manual transmissions have become increasingly commonplace and the number of forward ratios has increased to 5-speed and 6-speed manual transmissions for current vehicles. The alternative to a manual transmission is an automatic transmission; common types of automatic transmissions are the hydraulic automatic transmission (AT), and the continuously variable transmission (CVT), whereas the automated manual transmission (AMT) and dual-clutch transmissio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manual Transmission
A manual transmission (MT), also known as manual gearbox, standard transmission (in Canada, the United Kingdom, and the United States), or stick shift (in the United States), is a multi-speed motor vehicle transmission (mechanics), transmission system, where gear changes require the driver to manually select the gears by operating a gear stick and clutch (which is usually a foot pedal for cars or a hand lever for motorcycles). Early automobiles used ''sliding-mesh'' manual transmissions with up to three forward gear ratios. Since the 1950s, ''constant-mesh'' manual transmissions have become increasingly commonplace and the number of forward ratios has increased to 5-speed and 6-speed manual transmissions for current vehicles. The alternative to a manual transmission is an automatic transmission; common types of automatic transmissions are the Automatic transmission#Hydraulic automatic transmissions, hydraulic automatic transmission (AT), and the continuously variable transmissio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gear Ratio
A gear train is a mechanical system formed by mounting gears on a frame so the teeth of the gears engage. Gear teeth are designed to ensure the pitch circles of engaging gears roll on each other without slipping, providing a smooth transmission of rotation from one gear to the next. Features of gears and gear trains include: * The gear ratio of the pitch circles of mating gears defines the speed ratio and the mechanical advantage of the gear set. * A planetary gear train provides high gear reduction in a compact package. * It is possible to design gear teeth for gears that are non-circular, yet still transmit torque smoothly. * The speed ratios of chain and belt drives are computed in the same way as gear ratios. See bicycle gearing. The transmission of rotation between contacting toothed wheels can be traced back to the Antikythera mechanism of Greece and the south-pointing chariot of China. Illustrations by the Renaissance scientist Georgius Agricola show gear trains with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reduction Gear
A gear train is a mechanical system formed by mounting gears on a frame so the teeth of the gears engage. Gear teeth are designed to ensure the pitch circles of engaging gears roll on each other without slipping, providing a smooth transmission of rotation from one gear to the next. Features of gears and gear trains include: * The gear ratio of the pitch circles of mating gears defines the speed ratio and the mechanical advantage of the gear set. * A planetary gear train provides high gear reduction in a compact package. * It is possible to design gear teeth for gears that are non-circular, yet still transmit torque smoothly. * The speed ratios of chain and belt drives are computed in the same way as gear ratios. See bicycle gearing. The transmission of rotation between contacting toothed wheels can be traced back to the Antikythera mechanism of Greece and the south-pointing chariot of China. Illustrations by the Renaissance scientist Georgius Agricola show gear trains wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Needle Roller
A needle roller bearing is a special type of roller bearing which uses long, thin cylindrical rollers resembling needles. Ordinary roller bearings' rollers are only slightly longer than their diameter, but needle bearings typically have rollers that are at least four times longer than their diameter. Like all bearings, they are used to reduce the friction of a rotating surface. Compared to ball bearings and ordinary roller bearings, needle bearings have a greater surface area in contact with the races, so they can support a greater load. They are also thinner, so they require less clearance between the axle and the surrounding structure. Needle bearings are heavily used in automobile components such as rocker arm pivots, pumps, compressors, and transmissions. The drive shaft of a rear-wheel drive vehicle typically has at least eight needle bearings (four in each U joint) and often more if it is particularly long, or operates on steep slopes. See also * Race (bearing) * Tap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overdrive (mechanics)
Overdrive is the operation of an automobile cruising at sustained speed with reduced engine revolutions per minute (RPM), leading to better fuel consumption, lower noise, and lower wear. The term is ambiguous. The most fundamental meaning is that of an overall gear ratio between engine and wheels, such that the car is ''over-geared'', and cannot reach its potential top speed, i.e. the car could travel faster if it were in a lower gear, with the engine turning at higher RPM. The power produced by an engine increases with the engine's RPM to a maximum, then falls away. The point of maximum power is somewhat lower than the absolute maximum RPM to which the engine is limited, the " redline" RPM. A car's speed is limited by the power required to drive it against air resistance, which increases with speed. At the maximum possible speed, the engine is running at its point of maximum power, or ''power peak'', and the car is traveling at the speed where air resistance equals that max ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gear Lever
A gear stick (rarely spelled ''gearstick''), gear lever (both UK English), gearshift or shifter (both U.S. English), more formally known as a transmission lever, is a metal lever attached to the transmission of an automobile. The term ''gear stick'' mostly refers to the shift lever of a manual transmission, while in an automatic transmission, a similar lever is known as a gear selector. A gear stick will normally be used to change gear whilst depressing the clutch pedal with the left foot to disengage the engine from the drivetrain and wheels. Automatic transmission vehicles, including hydraulic (torque converter) automatic transmissions, automated manual and older semi-automatic transmissions (specifically clutchless manuals), like '' VW Autostick'', and those with continuously variable transmissions, do not require a physical clutch pedal. Alternative positions Gear sticks are most commonly found between the front seats of the vehicle, either on the center console (sometim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gearbox (Autocar Handbook, 13th Ed, 1935)
Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differential, and final drive shafts. In the United States the term is sometimes used in casual speech to refer more specifically to the gearbox alone, and detailed usage differs. The transmission reduces the higher engine speed to the slower wheel speed, increasing torque in the process. Transmissions are also used on pedal bicycles, fixed machines, and where different rotational speeds and torques are adapted. Often, a transmission has multiple gear ratios (or simply "gears") with the ability to switch between them as the speed varies. This switching may be done manually (by the operator) or automatically (by a control unit). Directional (forward and reverse) control may also be provided. Single-ratio transmissions also exist, which simply chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dog Clutch
A dog clutch (also known as a positive clutch or dog gears) 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 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 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 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commercial Motor
''Commercial Motor'' is a weekly magazine serving the road transport industry in the United Kingdom. Founded in 1905 by Edmund Dangerfield, it is notable for having been "the first journal to be devoted exclusively to the commercial vehicle engaged in the conveyance of goods or in passenger carrying". Originally named ''The Commercial Motor'', the title was shortened to ''Commercial Motor'' for the first issue of 1966. The publication is commonly referred to as 'CM' by its readers and editorial staff. ''Commercial Motor'' was initially published by Temple Press and since 2011 it has been published by Road Transport Media. Launch ''The Commercial Motor'' was launched in March 1905 by Temple Press. In the leader of the first issue it described itself as a "missionary and educative medium". For the first issue on 16 March, 20,000 copies were issued "in Britain and other countries, with the hope that the normal weekly circulation would be at least 5,000". Composition The content ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Take-off
A power take-off or power takeoff (PTO) is one of several methods for taking power from a power source, such as a running engine, and transmitting it to an application such as an attached implement or separate machine. Most commonly, it is a splined drive shaft installed on a tractor or truck allowing implements with mating fittings to be powered directly by the engine. Semi-permanently mounted power take-offs can also be found on industrial and marine engines. These applications typically use a drive shaft and bolted joint to transmit power to a secondary implement or accessory. In the case of a marine application, such shafts may be used to power fire pumps. In aircraft applications, such an accessory drive may be used in conjunction with a constant speed drive. Jet aircraft have four types of PTO units: internal gearbox, external gearbox, radial drive shaft, and bleed air, which are used to power engine accessories. In some cases, aircraft power take-off systems also provid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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