FACTOID # 5: Minnesota and Connecticut are both in the top 5 in saving money and total tax burden per capita.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Transmission (mechanics)

Using the principle of mechanical advantage, transmissions provide a torque-speed conversion[citation needed] (commonly known as "gear reduction" or "speed reduction") from a higher speed motor to a slower but more forceful output. Gearbox Software, LLC is a video game developer founded by Randy Pitchford, Brian Martel, Stephen Bahl, Landon Montgomery, and Rob Heironimus in January 1999. ... In physics and engineering, mechanical advantage (MA) is the factor by which a mechanism multiplies the force put into it. ...

Transmission types
Manual

Non-synchronous
Automatic A manual transmission (also known as a stick shift, straight drive, or standard transmission) is a type of transmission used in automotive applications. ... A sequential manual transmission (or sequential manual gearbox) is a type of manual transmission used on motorbikes and high-performance cars or auto racing, where gears are selected in order and random access to specific gears is not possible. ... A non-synchronous transmission is a form of transmission based on gears that do not use synchronizing mechanisms. ... The automatic gear selector in a Ford Five Hundred vehicle An automatic transmission (commonly abbreviated as AT) is an automobile gearbox that can change gear ratios automatically as the vehicle moves, thus freeing the driver from having to shift gears manually (similar but larger devices are also used for railroad...

Semi-automatic Tiptronic is a type of discrete automatic transmission developed by Porsche and used in its vehicles and those of its licensees. ... Semi-automatic transmission, or also known as clutchless manual transmission, automated manual transmission, e-gear, or paddle shift gearbox is a system which uses electronic sensors, processors and actuators to do gear shifts on the command of the driver. ...

Continuously variable
Bicycle gearing
 v  d  e 

Contents

A Twin-clutch gearbox or Dual Clutch Transmission (DCT) is a semi-automatic transmission with separate clutches for odd and even gears. ... The Direct-Shift Gearbox (Direktschaltgetriebe) is a dual-clutch gearbox designed by BorgWarner and initially licensed to Volkswagen Group (which owns the Volkswagen, Audi, SEAT, Bentley, Bugatti, Lamborghini, and Å koda brands). ... Saxomat was a type of automatic clutch available as an option on Saab 93, Volkswagen Beetle, Borgward, DKW, BMW, Opel, NSU and Glas. ... This article or section does not cite its references or sources. ... The continuously variable transmission (CVT) is a transmission in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios. ... Variomatic Variomatic is the stepless, fully automatic transmission of the Dutch car manufacturer DAF, using a drive belt and two pulleys. ... Audi developed a new stepless transmission named Multitronic. ... This article does not cite any references or sources. ... Derailleur gears are a variable ratio transmission system commonly used on bicycles, consisting of a chain, multiple sprockets and a mechanism to move the chain from one sprocket to another. ... Hub gears or internal-gear hubs are a type of gear system used on bicycles. ...

Explanation

Main gearbox of the Bristol 171 Sycamore helicopter
Main gearbox of the Bristol 171 Sycamore helicopter

Early transmissions included the right-angle drives and other gearing in windmills, horse-powered devices, and steam engines, in support of pumping, milling, and hoisting. Image File history File linksMetadata Size of this preview: 800 × 600 pixel Image in higher resolution (1600 × 1200 pixel, file size: 961 KB, MIME type: image/jpeg) Deutsches Museum Munich catégorie:hélicoptère Photo Jean-Patrick Donzey File links The following pages on the English Wikipedia link to... Image File history File linksMetadata Size of this preview: 800 × 600 pixel Image in higher resolution (1600 × 1200 pixel, file size: 961 KB, MIME type: image/jpeg) Deutsches Museum Munich catégorie:hélicoptère Photo Jean-Patrick Donzey File links The following pages on the English Wikipedia link to... For other uses, see Helicopter (disambiguation). ... This article is about machines that convert wind energy into mechanical energy. ... Binomial name Equus caballus Linnaeus, 1758 The horse (Equus caballus, sometimes seen as a subspecies of the Wild Horse, Equus ferus caballus) is a large odd-toed ungulate mammal, one of ten modern species of the genus Equus. ... // The term steam engine may also refer to an entire railroad steam locomotive. ... This article is about a mechanical device. ... An ancient Chinese tomb model of a foot-powered mill, Eastern Han Dynasty (25 - 220 AD), Freer Gallery of Art. ... Builders hoist, with small petrol engine A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. ...


Most modern gearboxes either reduce an unsuitable high speed and low torque of the prime mover output shaft to a more stable lower speed with higher torque, or do the opposite and provide a mechanical advantage (i.e increase in torque) to allow higher forces to be generated. Some of the simplest gearboxes merely change the physical direction in which power is transmitted. For other senses of this word, see torque (disambiguation). ... In physics and engineering, mechanical advantage (MA) is the factor by which a mechanism multiplies the force put into it. ...


Many typical automobile transmissions include the ability to select one of several different gear ratios. In this case, most of the gear ratios (simply called "gears") are used to slow down the output speed of the engine and increase torque. However, the highest gears may be "overdrive" types that increase the output speed. Car redirects here. ... Gears on a piece of farm equipment, gear ratio 1:1. ... An overdrive is sometimes a separate unit that fits into the back of a gearbox, as with this Fairey unit. ...


Uses

Gearboxes have found use in a wide variety of different—often stationary—applications. Stationary can mean: Look up stationary in Wiktionary, the free dictionary. ...


Transmissions are also used in agricultural, industrial, construction, mining and automotive equipment. In addition to ordinary transmission equipped with gears, such equipment makes extensive use of the hydrostatic drive and electrical adjustable-speed drives. Farming, ploughing rice paddy, in food, feed, fiber and other desired products by cultivation of certain plants and the raising of domesticated animals (livestock). ... For other uses, see Construction (disambiguation). ... This article is about mineral extractions. ... Car redirects here. ... A hydraulic or hydrostatic drivesystem or hydraulic power transmission is a drive- or transmission system that makes use of a hydraulic fluid under pressure to drive machinery. ... Adjustable speed drive (ASD) is one of the most general terms applied to equipment used to control the speed of machinery. ...


Simple

The simplest transmissions, often called gearboxes to reflect their simplicity (although complex systems are also called gearboxes in the vernacular), provide gear reduction (or, more rarely, an increase in speed), sometimes in conjunction with a right-angle change in direction of the shaft (typically in helicopters, see picture). These are often used on PTO-powered agricultural equipment, since the axial PTO shaft is at odds with the usual need for the driven shaft, which is either vertical (as with rotary mowers), or horizontally extending from one side of the implement to another (as with manure spreaders, flail mowers, and forage wagons). More complex equipment, such as silage choppers and snowblowers, have drives with outputs in more than one direction. For other uses, see Helicopter (disambiguation). ... A tractor PTO A power take-off (PTO) is a splined driveshaft, usually on a tractor or truck that can be used to provide power to an attachment or separate machine. ... A manure spreader or muck spreader is an agricultural machine used distribute manure over a field as a fertilizer. ... This article does not cite any references or sources. ... Silage (hay) somewhere in Allschwil or Schönenbuch, near Basel, Switzerland. ... A snow blower, snowblower, or snow thrower is a machine for removing snow from an area where it is not wanted, such as a driveway, sidewalk, roadway, or runway. ...


Regardless of where they are used, these simple transmissions all share an important feature: the gear ratio cannot be changed during use. It is fixed at the time the transmission is constructed. Gears on a piece of farm equipment, gear ratio 1:1. ...


For transmission types that overcome this issue, please see Continuously Variable Transmission, also known as CVT. The continuously variable transmission (CVT) is a transmission in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios. ...


Multi-ratio systems

Many applications require the availability of multiple gear ratios. Often, this is to ease the starting and stopping of a mechanical system, though another important need is that of maintaining good fuel economy. Gears on a piece of farm equipment, gear ratio 1:1. ... Fuel efficiency, sometimes also referred to as fuel economy and commonly gas mileage in the United States, is a numeric measure often used to describe the amount of fuel consumed with regard to the distance travelled in a transportation vehicle, such as an automobile. ...


Automotive basics

The need for a transmission in an automobile is a consequence of the characteristics of the internal combustion engine. Engines typically operate over a range of 600 to about 7000 revolutions per minute (though this varies, and is typically less for diesel engines), while the car's wheels rotate between 0 rpm and around 1800 rpm. Car redirects here. ... A colored automobile engine The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. ... For other uses, see Revolutions per minute (disambiguation). ...


Furthermore, the engine provides its highest torque outputs approximately in the middle of its range, while often the greatest torque is required when the vehicle is moving from rest or traveling slowly. Therefore, a system that transforms the engine's output so that it can supply high torque at low speeds, but also operate at highway speeds with the motor still operating within its limits, is required. Transmissions perform this transformation.


Most transmissions and gears used in automotive and truck applications are contained in a cast iron case, though sometimes aluminum is used for lower weight. There are three shafts: a mainshaft, a countershaft, and an idler shaft. For other uses, see Gear (disambiguation). ... Car redirects here. ... For other uses, see Truck (disambiguation). ... Cast iron usually refers to grey cast iron, but can mean any of a group of iron-based alloys containing more than 2% carbon (alloys with less carbon are carbon steel by definition). ... Aluminum is a soft and lightweight metal with a dull silvery appearance, due to a thin layer of oxidation that forms quickly when it is exposed to air. ...


The mainshaft extends outside the case in both directions: the input shaft towards the engine, and the output shaft towards the rear axle (on rear wheel drive cars). The shaft is suspended by the main bearings, and is split towards the input end. At the point of the split, a pilot bearing holds the shafts together. The gears and clutches ride on the mainshaft, the gears being free to turn relative to the mainshaft except when engaged by the clutches. A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. ... For other uses, see Clutch (disambiguation). ...


Automobile includes manual, automatic or semi-automatic transmission. A manual transmission (also known as a stick shift, straight drive, or standard transmission) is a type of transmission used in automotive applications. ... The automatic gear selector in a Ford Five Hundred vehicle An automatic transmission (commonly abbreviated as AT) is an automobile gearbox that can change gear ratios automatically as the vehicle moves, thus freeing the driver from having to shift gears manually (similar but larger devices are also used for railroad... Semi-automatic transmission, or also known as clutchless manual transmission, automated manual transmission, e-gear, or paddle shift gearbox is a system which uses electronic sensors, processors and actuators to do gear shifts on the command of the driver. ...


Manual

Main article: manual transmission

Manual transmission come in two basic types: A manual transmission (also known as a stick shift, straight drive, or standard transmission) is a type of transmission used in automotive applications. ...

  • a simple but rugged sliding-mesh or unsynchronized / non-synchronous system, where straight-cut spur gear sets are spinning freely, and must be synchronized by the operator matching engine revs to road speed, to avoid noisy and damaging "gear clash",
  • and the now common constant-mesh gearboxes which can include non-synchronised, or synchronized / synchromesh systems, where diagonal cut helical (and sometimes double-helical) gear sets are constantly "meshed" together, and a dog clutch is used for changing gears. On synchromesh 'boxes, friction cones or "synchro-rings" are used in addition to the dog clutch.

The former type is commonly found in many forms of racing cars, older heavy-duty trucks, and some agricultural equipment. A manual transmission (also known as a stick shift, straight drive, or standard transmission) is a type of transmission used in automotive applications. ... A manual transmission (also known as a stick shift, straight drive, or standard transmission) is a type of transmission used in automotive applications. ... Dog clutch used to drive the platter in a microwave oven. ... Trucks can refer to several things: The plural of: Truck, the motorized vehicle Truck, other uses of the singular As a name: Trucks was a rock band Trucks is a short story by Stephen King Trucks is a movie based on the Stephen King short story Trucks! is a television...


Manual transmissions dominate the car market outside of North America. They are cheaper, lighter, usually give better performance, and fuel efficiency (although the latest sophisticated automatic transmissions may yield results slightly closer to the ones yielded by manual transmissions). It is customary for new drivers to learn, and be tested, on a car with a manual gear change. In Malaysia, Denmark and Poland all cars used for testing (and because of that, virtually all those used for instruction as well) have a manual transmission. In Japan, Philippines, Germany, the Netherlands, New Zealand, Austria, the UK [1][2], Ireland[2], Sweden, France, Australia, Finland and Lithuania , a test pass using an automatic car does not entitle the driver to use a manual car on the public road; a test with a manual car is required.[citation needed] Manual transmissions are much more common than automatic transmissions in Asia, Africa, South America and Europe. North American redirects here. ... The United Kingdom of Great Britain and Northern Ireland is a country in western Europe, and member of the Commonwealth of Nations, the G8, the European Union, and NATO. Usually known simply as the United Kingdom, the UK, or (inaccurately) as Great Britain or Britain, the UK has four constituent... For other uses, see Asia (disambiguation). ... A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ... South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ... For other uses, see Europe (disambiguation). ...


Non-synchronous

Main article: Non-synchronous transmissions

There are commercial applications engineered with designs taking into account that the gear shifting will be done by an experienced operator. They are a manual transmission, but are known as non-synchronized transmissions. Dependent on country of operation, many local, regional, and national laws govern the operation of these types of vehicles (see Commercial Driver's License). This class may include commercial, military, agricultural, or engineering vehicles. Some of these may use combinations of types for multi-purpose functions. An example would be a PTO, or power-take-off gear. The non-synchronous transmission type requires an understanding of gear range, torque, engine power, and multi-functional clutch and shifter functions. Also see Double-clutching, and Clutch-brake sections of the main article at non-synchronous transmissions. Non-synchronous transmission is a form of transmission system based on gears that do not use synchronizing mechanisms. ... A commercial drivers license (CDL) is required in the United States to operate any type of vehicle with a gross weight of 26,001 lb (11,793 kg) or over including (but not limited to) tow trucks, tractor trailers and buses. ... 18 Wheeler was a Scottish rock band active in the early 1990s, consisting of Sean Jackson (vocals, guitar), David Keenan (guitar, vocals), Alan Hake (bass), and Neil Halliday (drums). ... An excavator. ... A tractor PTO A power take-off (PTO) is a splined driveshaft, usually on a tractor or truck that can be used to provide power to an attachment or separate machine. ... Non-synchronous transmission is a form of transmission system based on gears that do not use synchronizing mechanisms. ... Non-synchronous transmission is a form of transmission system based on gears that do not use synchronizing mechanisms. ... Non-synchronous transmission is a form of transmission system based on gears that do not use synchronizing mechanisms. ...


Automatic

Epicyclic gearing or planetary gearing as used in an automatic transmission.
Epicyclic gearing or planetary gearing as used in an automatic transmission.

Most modern North American, and many larger, high specification German cars have an automatic transmission that will select an appropriate gear ratio without any operator intervention. They primarily use hydraulics to select gears, depending on pressure exerted by fluid within the transmission assembly. Rather than using a clutch to engage the transmission, a fluid flywheel, or torque converter is placed in between the engine and transmission. It is possible for the driver to control the number of gears in use or select reverse, though precise control of which gear is in use may or may not be possible. The automatic gear selector in a Ford Five Hundred vehicle An automatic transmission (commonly abbreviated as AT) is an automobile gearbox that can change gear ratios automatically as the vehicle moves, thus freeing the driver from having to shift gears manually (similar but larger devices are also used for railroad... Image File history File links Epicyclic_gear_ratios. ... Image File history File links Epicyclic_gear_ratios. ... Epicyclic gearing is used here to increase output speed. ... The automatic gear selector in a Ford Five Hundred vehicle An automatic transmission (commonly abbreviated as AT) is an automobile gearbox that can change gear ratios automatically as the vehicle moves, thus freeing the driver from having to shift gears manually (similar but larger devices are also used for railroad... Table of Hydraulics and Hydrostatics, from the 1728 Cyclopaedia. ... This article is about pressure in the physical sciences. ... For other uses, see Clutch (disambiguation). ... ZF torque converter A cut-away model of a torque converter A torque converter is a modified form of a hydrodynamic fluid coupling, and like the fluid coupling, is used to transfer rotating power from a prime mover, such as an internal combustion engine or electric motor, to a rotating...


Automatic transmissions are easy to use. In the past, automatic transmissions of this type have had a number of problems; they were complex and expensive, sometimes had reliability problems (which sometimes caused more expenses in repair), have often been less fuel-efficient than their manual counterparts (due to "slippage" in the torque converter), and their shift time was slower than a manual making them uncompetitive for racing. With the advancement of modern automatic transmissions this has changed.[citation needed] Shift time refers to the amount of time without power between gears usually with reference to motor vehicles but can apply to any gearbox. ...


Since their inception, automatic transmissions have been very popular in the United States, and some vehicles are not available with manual gearboxes anymore. In Europe automatic transmissions are gaining popularity as well.[citation needed] For other uses, see Europe (disambiguation). ...


Attempts to improve the fuel efficiency of automatic transmissions include the use of torque converters which lock up beyond a certain speed, or in the higher gear ratios, eliminating power loss, and overdrive gears which automatically actuate above certain speeds; in older transmissions both technologies could sometimes become intrusive, when conditions are such that they repeatedly cut in and out as speed and such load factors as grade or wind vary slightly. Current computerized transmissions possess very complex programming to both maximize fuel efficiency and eliminate any intrusiveness.[citation needed] ZF torque converter A cut-away model of a torque converter A torque converter is a modified form of a hydrodynamic fluid coupling, and like the fluid coupling, is used to transfer rotating power from a prime mover, such as an internal combustion engine or electric motor, to a rotating...


For certain applications, the slippage inherent in automatic transmissions can be advantageous; for instance, in drag racing, the automatic transmission allows the car to be stopped with the engine at a high rpm (the "stall speed") to allow for a very quick launch when the brakes are released; in fact, a common modification is to increase the stall speed of the transmission. This is even more advantageous for turbocharged engines, where the turbocharger needs to be kept spinning at high rpm by a large flow of exhaust in order to keep the boost pressure up and eliminate the turbo lag that occurs when the engine is idling and the throttle is suddenly opened. Top Fuel dragster Drag racing is a sport in which cars race down a track with a set distance as fast as possible. ... Turbocharger Cut-away A turbocharger is a device used in internal-combustion engines to increase the power output of the engine by increasing the mass of oxygen and fuel entering the engine. ... Turbo lag is the delay between when you press the throttle and the turbocharger starts producing boost pressure. ...


Semi-automatic

Main article: semi-automatic transmission

The creation of computer control also allowed for a sort of cross-breed transmission where the car handles manipulation of the clutch automatically, but the driver can still select the gear manually if desired. This is sometimes called a "clutchless manual," "dual-clutch," or "automated manual" transmission. Many of these transmissions allow the driver to give full control to the computer. They are generally designed using manual transmission "internals", and when used in passenger cars, have synchromesh operated helical constant mesh gear sets. Semi-automatic transmission, or also known as clutchless manual transmission, automated manual transmission, e-gear, or paddle shift gearbox is a system which uses electronic sensors, processors and actuators to do gear shifts on the command of the driver. ... For other uses, see Clutch (disambiguation). ...


Specific type of this transmission includes: Easytronic, Geartronic, and Direct-Shift Gearbox. Tardtronic is a type of transmission or gearbox used in some Opel / Vauxhall cars. ... Volvos name for the sequential gearbox, there is no clutch. ... The Direct-Shift Gearbox (Direktschaltgetriebe) is a dual-clutch gearbox designed by BorgWarner and initially licensed to Volkswagen Group (which owns the Volkswagen, Audi, SEAT, Bentley, Bugatti, Lamborghini, and Å koda brands). ...


There are also sequential transmissions which use the rotation of a drum to switch gears. [1] For other uses, see Drum (disambiguation). ...


Bicycle gearing

Bicycles usually have a system for selecting different gear ratios. There are two main types: derailleur gears and hub gears. The derailleur type is the most common, and the most visible, using sprocket gears. Typically there are several gears available on the rear sprocket assembly, attached to the rear wheel. A few more sprockets are usually added to the front assembly as well. Multiplying the number of sprocket gears in front by the number to the rear gives the number of gear ratios, often called "speeds". This article does not cite any references or sources. ... Derailleur gears are a variable ratio transmission system commonly used on bicycles, consisting of a chain, multiple sprockets and a mechanism to move the chain from one sprocket to another. ... Hub gears or internal-gear hubs are a type of gear system used on bicycles. ... For other uses, see Bicycle (disambiguation). ... Derailleur gears are a variable ratio transmission system commonly used on bicycles, consisting of a chain, multiple sprockets and a mechanism to move the chain from one sprocket to another. ... 8-Speed hub gear by Shimano Hub gears or internal gears are a type of gear system used on bicycles. ... This article does not cite its references or sources. ...


Hub gears use epicyclic gearing and are enclosed within the axle of the rear wheel. Because of the small space, they typically offer fewer different speeds, although at least one has reached 14 gear ratios.[3] Epicyclic gearing is used here to increase output speed. ... An axle is a central shaft for a rotating wheel or gear. ...


Usual jamming includes: worn teeth, damages caused by a faulty chain, damage due to thermal dilatation, broken teeth due to excessive use of power when pedalling and lubrication flaw caused by negligency.


Uncommon types

Continuously variable

The Continuously Variable Transmission (CVT) is a transmission in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios. The continuously variable transmission (CVT) is a transmission in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios. ...


The continuously variable transmission (CVT) should not be confused with the Infinitely Variable Transmission (IVT) (See below). Generally, the usage of the term 'CVT' is not used for infinitely variable transmissions because most CVT's are not IVT's.


The other mechanical transmissions described above only allow a few different gear ratios to be selected, but this type of transmission essentially has an infinite number of ratios available within a finite range. The continuously variable transmission allows the relationship between the speed of the engine and the speed of the wheels to be selected within a continuous range. This can provide even better fuel economy if the engine is constantly running at a single speed. The transmission is in theory capable of a better user experience, without the rise and fall in speed of an engine, and the jerk felt when changing gears. The continuously variable transmission (CVT) is a transmission in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios. ... This article is about the physics concept of jerk. ...


Infinitely variable

The IVT is a specific type of CVT that has an infinite range of input/output ratios in addition to its infinite number of possible ratios; this qualification for the IVT implies that its range of ratios includes a zero output/input ratio that can be continuously approached from a defined 'higher' ratio. A zero output implies an infinite input, which can be continuously approached from a given finite input value with an IVT. [Note: remember that so-called 'low' gears are a reference to low ratios of output/input, which have high input/output ratios that are taken to the extreme with IVT's, resulting in a 'neutral', or non-driving 'low' gear limit.]


Most (if not all) IVT's result from the combination of a CVT with an epicyclic gear system (which is also known as a planetary gear system) that facilitates the subtraction of one speed from another speed within the set of input and planetary gear rotations. This subtraction only needs to result in a continuous range of values that includes a zero output; the maximum output/input ratio can be arbitrarily chosen from infinite practical possibilities through selection of extraneous input or output gear, pulley or sprocket sizes without affecting the zero output or the continuity of the whole system. Importantly, the IVT is distinguished as being 'infinite' in its ratio of high gear to low gear within its range; high gear is infinite times higher than low gear. The IVT is always engaged, even during its zero output adjustment.


The term 'infinitely variable transmission' does not imply reverse direction, disengagement, automatic operation, or any other quality except ratio selectabilty within a continuous range of input/output ratios from a defined minimum to an undefined, 'infinite' maximum. This means continuous range from a defined output/input to zero output/input ratio.


Electric variable

The Electric Variable Transmission(EVT) is a transmission that achieves CVT action and in addition can use separate power inputs to produce one output. An EVT usually is executed in design with an epicyclic differential gear system (which is also known as a planetary gear system). The epicyclic differential gearing performs a "power-split" function, directly connecting a portion of the mechanical power directly through the transmission and splitting off a portion for subsequent conversion to electrical power via a motor/generator. Hence, the EVT is called a Power Split Transmission (PST) by some.


The directly connected portion of the power travelling through the EVT is referred to as the "mechanical path". The remaining power travels down the EVT's "electrical path". That power may be recombined at the output of the transmission or stored for later, more opportune use via a second motor/generator (and energy storage device) connected to the transmission output.


The pair of motor/generators forms an Electric Transmission in its own right, but at a lower capacity, than the EVT it is contained within. Generally the Electric Transmission capacity within the EVT is a quarter to a half of the capacity of the EVT. Good reasons to use an EVT instead of an equivalently-sized Electrical transmission is that the mechanical path of the EVT is more compact and efficient than the electrical path.


The EVT is the essential method for transmitting power in some hybrid vehicles, enabling an Internal Combustion Engine (ICE) to be used in conjunction with motor/generators for vehicle propulsion, and having the ability to control the portion of the mechanical power used directly for propelling the vehicle and the portion of mechanical power that is converted to electric power and recombined to drive the vehicle.


The EVT and power sources are controlled to provide a balance between the power sources that increases vehicle fuel economy while providing advantageous performance when needed. The EVT may also be used to provide electrically generated power to charge large storage batteries for subsequent electric motor propulsion as needed, or to convert vehicle kinetic energy to electricity through 'regenerative braking' during deceleration. Various configurations of power generation, usage and balance can be implemented with a EVT, enabling great flexibility in propelling hybrid vehicles.


The Toyota single mode hybrid and General Motor 2 Mode hybrid are production systems that use EVTs. The Toyota system is in the Prius, Highlander, and Lexus RX400h and GS450h models. The GM system is the Allison Bus hybrid powertrains and are in the Tahoe and Yukon models. The Toyota system uses one power-split epicyclic differential gearing system over all driving conditions and is sized with an electrical path rated at approximately half the capacity of the EVT. The GM system uses two different EVT ranges: one designed for lower speeds with greater mechnical advantage, and one designed for higher speeds, and the electrical path is rated at approximately a quarter of the capacity of the EVT. Other arrangements are possible and applications of EVT's are growing rapidly in number and variety.


EVT's are capable of continuously modulating output/input speed ratios like mechanical CVT's, but offer the distinct difference and benefit of being able to also apportion power from two different sources to one output.


Hydrostatic

Hydrostatic transmissions transmit all power hydraulically, using the components of hydraulic machinery. There is no solid coupling of the input and output. One half of the transmission is a hydraulic pump and the other half is a hydraulic motor, or hydraulic cylinder. Hydrostatic drive systems are used on excavators, lawn tractors, forklifts, winch drive systems, heavy lift equipment, agricultural machinery, etc. Table of Hydraulics and Hydrostatics, from the 1728 Cyclopaedia. ... Excavator. ...


Hydraulic drive systems can be used as an extra transmission between motor and f.i. wheels.


Hydrodynamic

If the hydraulic pump and/or hydraulic motor are not hydrostatic, but hydrodynamic, then the transmission can be called hydrodynamic. The pump and motor can consist of rotating vanes without seals. The pump and motor can be placed in reasonable proximity. The transmission ratio can be made to vary by means of additional rotating vanes, an effect similar to varying the pitch of an airplane propeller.


The torque converter in most American cars is a hydrodynamic transmission, placed ahead of the automatic transmission. ZF torque converter A cut-away model of a torque converter A torque converter is a modified form of a hydrodynamic fluid coupling, and like the fluid coupling, is used to transfer rotating power from a prime mover, such as an internal combustion engine or electric motor, to a rotating...


It was possible to drive the Dynaflow transmission without shifting the mechanical gears. Dynaflow was the trademark name for an automatic transmission developed and built by General Motors Buick Division from the late 1940s to the mid 1960s. ...


Hydrodynamic transmissions tend to be inefficient due to energy losses in the fluid.


Electric

Electric transmissions convert the mechanical power of the engine(s) to electricity with electric generators and convert it back to mechanical power with electric motors. Electrical or electronic adjustable-speed drive control systems are used to control the speed and torque of the motors. If the generators are driven by turbines, such arrangements are called turbo-electric. Likewise installations powered by diesel-engines are called diesel-electric. Diesel-electric arrangements are used on many railway locomotives. Generator redirects here. ... For other kinds of motors, see motor. ... Adjustable speed drive (ASD) is one of the most general terms applied to equipment used to control the speed of machinery. ... A Siemens steam turbine with the case opened. ... UP 18, a locomotive with a turbo-electric drivetrain A turbo-electric transmission uses electric generators to convert the mechanical energy of a turbine (steam or gas) into electric energy and electric motors to convert it back into mechanical energy to power the driveshafts. ... Diesel engines in a museum Diesel generator on an oil tanker A diesel engine is an internal combustion engine which operates using the Diesel cycle. ... A number of vehicles use a diesel-electric powerplant for providing locomotion. ...


See also

Roller chain and sprocket Mack AC delivery truck at the Petersen Automotive Museum with chain drive visible Chain drive was a popular power transmission system from the earliest days of the automobile. ... Non-synchronous transmission is a form of transmission system based on gears that do not use synchronizing mechanisms. ...

External links

Wikimedia Commons has media related to:
Look up gearbox in Wiktionary, the free dictionary.

Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 151 languages. ...

References

For other uses, see Gear (disambiguation). ... Spur gears found on a piece of farm equipment. ... Worm drives consist of a cylinder with a spiral groove mounted on a shaft. ... Rack and pinion animation A rack and pinion is a pair of gears which convert rotational motion into linear motion. ... Epicyclic gearing is used here to increase output speed. ... The sun and planet gear was a method of converting vertical motion to rotary motion and utilised a reciprocating steam engine. ... A harmonic drive is an input/output gear reduction mechanism. ... A Cycloidal Drive or cycloidal speed reducer is a mechanism for reducing the speed of an input shaft by a certain ratio. ... Non-circular gear example A non-circular gear (NCG) is a special gear design with special characteristics and purpose. ... Download high resolution version (500x680, 39 KB)Description: Photograph of spur gears on a piece of farm equipment. ... Spur gears found on a piece of farm equipment. ... Bevel gears are gears where the axes of the two shafts intersect and the tooth-bearing faces of the gears themselves are conically shaped. ... For other uses, see Gear (disambiguation). ... A hypoid is the name given to a type of helical (spiral) gear. ... The involute gear profile is the most commonly used system for gearing today. ... The cycloidal gear profile is used in mechanical clocks. ... In an automobile and other four-wheeled vehicles, a differential is a device, usually consisting of gears, that allows each of the driving wheels to rotate at different speeds, while supplying equal torque to each of them. ... A gear coupling is a mechanical device for transmitting torque between two shafts that are not coaxial. ... A gear train is a set or system of gears arranged to transfer rotational torque from one part of a mechanical sytem to another. ... This article does not cite any references or sources. ... The continuously variable transmission (CVT) is a transmission in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios. ... Offset, ANSI/AGMA 1012-G05 Offset is the perpendicular distance between the axes of hypoid gears or offset face gears. ... Freewheel mechanism In mechanical or automotive engineering, a freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. ... On a bicycle, the cassette or the freewheel is the set of rear sprockets that attaches to a hub on the rear wheel. ... Derailleur gears are a variable ratio transmission system commonly used on bicycles, consisting of a chain, multiple sprockets and a mechanism to move the chain from one sprocket to another. ... A fixed gear bicycle A fixed-gear bicycle or fixed wheel bicycle, is any bicycle without a freewheel and usually only one gear ratio. ... Hub gears or internal-gear hubs are a type of gear system used on bicycles. ... A shaft-driven bicycle. ... This article does not cite its references or sources. ... Photo showing two ball screws. ... A leadscrew is a screw specialized for the purpose of translating rotational to linear motion. ... Jackscrew ( animation) A jackscrew mechanism uses a long threaded rod used to position a matching nut at any position along its length. ... v-belt flat belt Belts are used to mechanically link two or more rotating items. ... Roller chain and sprocket Mack AC delivery truck at the Petersen Automotive Museum with chain drive visible Chain drive was a popular power transmission system from the earliest days of the automobile. ... There are very few or no other articles that link to this one. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Car redirects here. ... Petroleum electric hybrid vehicles make use of both an on-board rechargeable energy storage system (RESS) and a fueled power source for vehicle propulsion. ... For other uses, see Wheel (disambiguation). ... Firestone tire This article is about pneumatic tires. ... All-terrain tyre An All-terrain tyre is a type of automotive tyre most commonly found on Four wheel drive vehicles. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... Contact patch is the name applied to the area of a vehicles tire that is in contact with the road surface. ... The term Custom wheel is used refer to the wheels of a vehicle which have either been modified from the vehicle manufacturers standard, or have replaced the manufacturers standard. ... A drive wheel is a wheel in an automotive vehicle that receives power from the power train. ... A reflective hubcap A hubcap or wheel cover is a decorative disk on an automobile wheel that covers at least a central portion of the wheel. ... Magnesium alloy wheels, or mag wheels, are sometimes used on racing cars, in place of heavier steel or aluminium wheels, for better performance. ... A Mud Terrain Tyre is a type of automotive tyre which may be fitted as an aftermarket option to four wheel drive vehicles. ... Paddle tires are off road vehicle tires specifically designed for use in sand. ... A radial tire (more properly, a radial-ply tire) is a particular design of automotive tire (in British English, tyre). ... Rostyle wheels are a particular design of wheels for cars made by the British firm of Rubery Owen, a diversified industrial company which made many car parts. ... // A run flat tire is a pneumatic vehicle tire that is designed to resist the effects of deflation and to enable the vehicle to continue to be driven — albeit at reduced speeds (i. ... A schrader valve on a bicycle tire. ... A wheel with a slick tire. ... This article or section does not adequately cite its references or sources. ... Automobile tires are described by an alphanumeric code which is generally molded into the side-wall of the tire. ... A tire pressure monitoring system (TPMS) is an electronic system to monitor the air pressure inside a pneumatic tire. ... The tread of a tire or caterpillar track refers to the pattern visible on its circumference that makes contact with the road. ... The Treadwear Grade of a tire is the numeric portion of the Uniform Tire Quality Grade Standards (UTQG) that are printed on the sidewall of a tire. ... It has been suggested that this article or section be merged with tire. ... Wire wheels, (wire spoked wheels), today are still used on many motorcycles and most bicycles. ... The automatic gear selector in a Ford Five Hundred vehicle An automatic transmission (commonly abbreviated as AT) is an automobile gearbox that can change gear ratios automatically as the vehicle moves, thus freeing the driver from having to shift gears manually (similar but larger devices are also used for railroad... For other uses, see Clutch (disambiguation). ... The continuously variable transmission (CVT) is a transmission in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios. ... In an automobile and other four-wheeled vehicles, a differential is a device, usually consisting of gears, for allowing each of the driving wheels to rotate at different speeds, while supplying equal torque to each of them. ... The Direct-Shift Gearbox (Direktschaltgetriebe) is a dual-clutch gearbox designed by BorgWarner and initially licensed to Volkswagen Group (which owns the Volkswagen, Audi, SEAT, Bentley, Bugatti, Lamborghini, and Škoda brands). ... This article is about the mechanical device. ... A clutch is a mechanism for transmitting rotation, which can be both engaged and disengaged. ... Epicyclic gearing is used here to increase output speed. ... A fluid coupling is a hydraulic device used for trasmitting mechanical shaft power from a rotating driver to a rotating driven load. ... An automatic transmission is an automobile gearbox that can change gear ratios automatically as the car moves, thus freeing the driver from having to shift gears manually. ... A gear stick (also gearstick, gear lever and gear shifter) is the lever used to change gear in a vehicle, such as an automobile, with manual transmission or automatic transmission. ... A gearbox is an assembly of gears allowing the rotational speed of an input shaft to be changed to a different speed. ... Hydramatic (also known as Hydra-Matic) was an automatic transmission developed by General Motorss Oldsmobile division. ... In automotive applications, a limited slip differential (LSD) is a modified or derived type of differential gear arrangement that allows for some difference in rotational velocity of the output shafts, but does not allow the difference in speed to increase beyond a preset amount. ... A locking differential or locker is a modified type of automotive differential. ... A manual transmission (also known as a stick shift, straight drive, or standard transmission) is a type of transmission used in automotive applications. ... Audi developed a new stepless transmission named Multitronic. ... Roto Hydramatic (sometimes spelled Roto Hydra-Matic or Roto-Hydramatic) was an automatic transmission built by General Motors and used on some Oldsmobile and Pontiac models from 1961 to 1964. ... Saxomat was a type of automatic clutch available as an option on Saab 93, Volkswagen Beetle, Borgward, DKW, BMW, Opel, NSU and Glas. ... Semi-automatic transmission, or also known as clutchless manual transmission, automated manual transmission, e-gear, or paddle shift gearbox is a system which uses electronic sensors, processors and actuators to do gear shifts on the command of the driver. ... The Super Turbine 300 (abbreviated ST-300) was a two-speed automatic transmission built by General Motors. ... Tiptronic is a type of discrete automatic transmission developed by Porsche and used in its vehicles and those of its licensees. ... ZF torque converter A cut-away model of a torque converter A torque converter is a modified form of a hydrodynamic fluid coupling, and like the fluid coupling, is used to transfer rotating power from a prime mover, such as an internal combustion engine or electric motor, to a rotating... A transaxle, in the automotive field, is a component that combines the functionality of the transmission, the differential and the drive axle into one integrated assembly. ... A Transmission Control Unit is a device that controls modern electronic automatic transmissions. ... Turbo-Hydramatic is the registered tradename of an automatic transmission developed and produced by General Motors. ... A universal joint A universal joint, U joint, Cardan joint or Hardy-Spicer joint is a joint in a rigid rod that allows the rod to bend in any direction. ... Steering is the term applied to the collection of components, linkages, etc. ... Ackermann steering geometry is a geometric arrangement of linkages in the steering of a car or other vehicle designed to solve the problem of wheels on the inside and outside of a turn needing to trace out circles of different radii. ... A wheel with a negative camber angle Camber angle is the angle made by the wheel of an automobile; specifically, it is the angle between the vertical axis of the wheel and the vertical axis of the vehicle when viewed from the front or rear. ... Car handling and vehicle handling is a description of the way wheeled vehicles perform transverse to their direction of motion, particularly during cornering and swerving. ... θ is the caster angle, red line is the pivot line, grey area is the tire Caster (or castor) angle is the angular displacement from the vertical axis of the suspension of a steered wheel in a car or other vehicle, measured in the longitudinal direction. ... Ideally, when the car reaches the turn, the driver will steer it along the line marked with green dots. ... Power steering is a system for reducing the steering effort on cars by using an external power source to assist in turning the wheels. ... Rack and pinion animation A rack and pinion is a pair of gears which convert rotational motion into linear motion. ... Toe is the symmetric angle that each wheel makes with the longitudinal axis of the vehicle, as a function of static geometry, and kinematic and compliant effects. ... Torque steering is an effect in front wheel drive cars caused by large amounts of torque affecting steering in such a way as to make the front wheels squirm (oscillate) from side to side under heavy acceleration, noticeable to the driver by the steering wheel being tugged back and forth... Ideally, when the car reaches the turn, the driver will steer it along the line marked with green dots. ... The front suspension components of a Ford Model T. Suspension is the term given to the system of springs, shock absorbers and linkages that connects a vehicle to its wheels. ... An axle is a central shaft for a rotating wheel or gear. ... Solid axle and Panhard rod on a 2002 Mazda MPV A beam axle is a suspension system, also called a solid axle, in which one set of wheels is connected laterally by a single beam or shaft. ... A compression coil spring A tension coil spring A selection of conical coil springs A Coil spring, also known as a helical spring, is a mechanical device, which is typically used to store energy and subsequently release it, to absorb shock, or to maintain a force between contacting surfaces. ... A de Dion tube is an automobile suspension technology. ... A double wishbone suspension is an automobile independent suspension design using two parallel wishbone-shaped arms to locate the wheel. ... Electronic stability control (ESC) is a computerized technology that improves the safety of a vehicles handling by detecting and preventing skids. ... Hydragas is a type of automotive suspension system used in many cars produced by British Leyland and its successor companies. ... Hydrolastic is a type of automotive suspension system used in many cars produced by British Motor Corporation (BMC) and its successor companies. ... Hydropneumatic is the name given to a suspension system invented by Citroën and fitted to Citroën cars, as well as being adapted by other car manufacturers, notably Rolls-Royce, Mercedes-Benz and Peugeot. ... Independent suspension is broad term for any automobile suspension system that allows each wheel on the same axle to move vertically (i. ... Suspension, showing tie rod, steering arm, king pin (axis) ball joints The kingpin is the main pivot in the steering mechanism of a car or other vehicle. ... A traditional leaf spring arrangement. ... A live axle is a type of beam axle suspension system that uses the driveshafts that transmit power to the wheels to connect the wheels laterally so that they move together as a unit. ... A simple MacPherson strut suspension on the left front wheel of a rear-wheel drive vehicle. ... A multi-link suspension is a type of vehicle suspension design typically used in independent suspensions, using three or more lateral arms, and one or more longitudinal arms. ... A Panhard rod is a component of a car suspension system that provides lateral location of the axle. ... A trailing-arm suspension is an automobile suspension design in which one or more arms (or links) are connected between (and perpendicular to) the axle and the chassis. ... Gasfilled Shock absorber. ... sway bar (also stabilizer bar, anti-sway bar, roll bar, or anti-roll bar, ARB) is an automobile suspension device. ... A swing axle is a simple type of independent suspension first used in early 20C. aircraft, Sopwith, Fokker et al, 1910 or earlier usually with rubber bungee and no damping. ... Torsion beam suspension, also known as a torsion bar or torsion spring suspension, is a vehicle suspension system. ... A trailing-arm suspension is an automobile suspension design in which one or more arms (or links) are connected between (and perpendicular to and forward of) the axle and the chassis. ... This does not cite its references or sources. ... Watts Linkage The Watts linkage was invented by James Watt (1736--1819) to constrain the movement of a piston in a steam engine to move in a straight line. ... A double wishbone suspension is an automobile independent suspension design using two parallel wishbone-shaped arms to locate the wheel. ... It has been suggested that Drum brake and Disc brake be merged into this article or section. ... An anti-lock braking system (ABS) (translated from German, Antiblockiersystem) is a system on motor vehicles which prevents the wheels from locking while braking. ... It has been suggested that this article or section be merged into Vehicle brake. ... It has been suggested that this article or section be merged into Vehicle brake. ... Electronic stability control (ESC) is a computerized technology that improves the safety of a vehicles handling by detecting and preventing skids. ... In cars, the hand brake (also known as the emergency brake, e-brake, park brake, or parking brake) is a supplementary system that can be used if the vehicles primary brake system (usually hydraulic brakes) has a failure. ... The hydraulic brake is an arrangement of braking mechanism which uses hydraulic fluid, typically some type of light-viscosity petroleum oil, to transfer pressure from the controlling unit, which is usually near the operator of the vehicle, to the actual brake mechanism, which is usually at or near the wheel... An inboard braking system is an automobile technology where the brakes are not located in the wheels, as is common today, but instead near the differential. ... Brake linings are the consumable surfaces in braking systems, especially those used in vehicles. ... Vehicle braking system fade, or brake fade is the reduction in stopping power that can occur after repeated application of the brakes, especially in high load or high speed conditions. ... Brake fluid is a type of hydraulic fluid used in brake applications in automobiles and light trucks. ... Hydraulic fluids are a large group of mineral oils, water-based or water used as the medium in hydraulic systems. ... Close-up of a disc brake on a car Brake bleeding is the procedure performed on hydraulic brake systems whereby the brake lines (the pipes and hoses containing the brake fluid) are purged of any air bubbles. ... It has been suggested that Exhaust brake be merged into this article or section. ... This article does not cite any references or sources. ... A regenerative brake is an apparatus, a device or system which allows a vehicle to recapture and store part of the kinetic energy that would otherwise be lost to heat when braking. ...

  Results from FactBites:
 
Automatic Transmissions A Short Course on How They Work (5226 words)
Transmission repairs describes the types of repairs that are typically performed on transmissions from minor adjustments to complete overhauls.
The transmission oil pump (not to be confused with the pump element inside the torque converter) is responsible for producing all the oil pressure that is required in the transmission.
If a late model transmission (computer-controlled transmissions started becoming popular in the early '90s) is not shifting properly, it is often the result of a computer sending incorrect signals due to a faulty sensor, or the transmission is not reacting to the computer command because of a bad connection or defective solenoid pack.
Transmission (mechanics) - Wikipedia, the free encyclopedia (1687 words)
In mechanics, a transmission or gearbox is the gear and/or hydraulic system that transmits mechanical power from a prime mover (which can be an engine or electric motor), to some form of useful output device.
Transmissions are also used in agricultural, industrial, construction, and mining equipment.
In the past, automatic transmissions of this type have had a number of problems; they were complex and expensive, sometimes had reliability problems (which sometimes caused more expenses in repair), have often been less fuel-efficient than their manual counterparts and their shift time was slower than a manual making them uncompetitive for racing.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m