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Crawl Ratio
Crawl ratio is a term used in the automotive world to describe the highest gear ratio that a vehicle is capable of. Note that gear ratio, also known as speed ratio, of a gear train is defined as the ratio of the angular velocity of the input gear to the angular velocity of the output gear, and thus a higher gear ratio implies a larger speed reduction, i.e. the input speed is reduced more at the output. The highest gear ratio is obtained at either first gear or reverse gear, but only first gear is typically taken into consideration while talking about crawl ratio. A potentially confusing terminology is that although a better crawl ratio is achieved by a higher gear ratio, it is common to refer to a better crawl ratio as “lower crawl ratio” rather than “higher crawl ratio” because it’s for driving at lower speeds. The crawl ratio is aptly named because when a vehicle is driven using the lowest gear (i.e. first gear), it moves the slowest (i.e. crawl speed) at a given engine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gear Ratio
A gear train or gear set is a machine element of a mechanical system formed by mounting two or more gears on a frame such that the teeth of the gears engage. Gear teeth are designed to ensure the Pitch circle diameter (gears), 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 epicyclic gearing, planetary gear train provides high gear reduction in a compact package. * It is possible to design gear teeth for gears that are non-circular gear, non-circular, yet still transmit torque smoothly. * The speed ratios of chain drive, chain and belt (mechanical), 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 Antikyt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Revolutions Per Minute
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 defines a physical quantity called ''rotation'' (or ''number of revolutions''), dimensionless, whose instantaneous rate of change is called ''rotational frequency'' (or ''rate of rotation''), with units of reciprocal seconds (s−1). A related but distinct quantity for describing rotation is ''angular frequency'' (or ''angular speed'', the magnitude of angular velocity), for which the SI unit is the radian per second (rad/s). Although they have the same dimensions (reciprocal time) and base unit (s−1), the hertz (Hz) and radians per second (rad/s) are special names used to express two different but proportional ISQ quantities: frequency and angular frequency, respectively. The conversions between a frequency and an angular frequency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torque
In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. When being referred to as moment of force, it is commonly denoted by . Just as a linear force is a push or a pull applied to a body, a torque can be thought of as a twist applied to an object with respect to a chosen point; for example, driving a screw uses torque to force it into an object, which is applied by the screwdriver rotating around its axis to the drives on the head. Historical terminology The term ''torque'' (from Latin , 'to twist') is said to have been suggested by James Thomson and appeared in print in April, 1884. Usage is attested the same year by Silvanus P. Thompson in the first edition of ''Dynamo-Electric Machinery''. Thompson describes his usage of the term as follows: Today, torque is referred to using d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheel
A wheel is a rotating component (typically circular in shape) that is intended to turn on an axle Bearing (mechanical), bearing. The wheel is one of the key components of the wheel and axle which is one of the Simple machine, six simple machines. Wheels, in conjunction with axles, allow heavy objects to be moved easily facilitating movement or transportation while supporting a load, or performing labor in machines. Wheels are also used for other purposes, such as a ship's wheel, steering wheel, potter's wheel, and flywheel. Common examples can be found in transport applications. A wheel reduces friction by facilitating motion by rolling together with the use of axles. In order for a wheel to rotate, a Moment (physics), moment must be applied to the wheel about its axis, either by gravity or by the application of another external force or torque. Terminology The English word '':wikt:wheel, wheel'' comes from the Old English word , from Proto-Germanic language, Proto-Germanic , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drive Train
A drivetrain (also frequently spelled as drive train or sometimes drive-train) or transmission system, is the group of components that deliver mechanical power from the prime mover to the driven components. In automotive engineering, the drivetrain is the components of a motor vehicle that deliver power to the drive wheels. This excludes the engine or motor that generates the power. In marine applications, the drive shaft will drive a propeller, thruster, or waterjet rather than a drive axle, while the actual engine might be similar to an automotive engine. Other machinery, equipment and vehicles may also use a drivetrain to deliver power from the engine(s) to the driven components. In contrast, the powertrain is considered to include both the engine and/or motor(s) as well as the drivetrain. Function The function of the drivetrain is to couple the engine that produces the power to the driving wheels that use this mechanical power to rotate the axle. This connection invol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission (mechanics)
A transmission (also called a gearbox) is a mechanical device invented by Louis Renault (industrialist), Louis Renault (who founded Renault, Renault) which uses a gear set—two or more gears working together—to change the speed, direction of rotation, or torque multiplication/reduction in a machine. Transmissions can have a single fixed-gear ratio, multiple distinct gear ratios, or continuously variable ratios. Variable-ratio transmissions are used in all sorts of machinery, especially vehicles. Applications Early uses Early transmissions included the right-angle drives and other gearing in windmills, horse-powered devices, and steam engine, steam-powered devices. Applications of these devices included pumps, mill (grinding), mills and Hoist (device), hoists. Bicycles Bicycles traditionally have used hub gear or Derailleur gear transmissions, but there are other more recent design innovations. Automobiles Since the torque and Horsepower, power output of an interna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential (mechanics)
A differential is a gear train with three drive shafts that has the property that the rotational speed of one shaft is the average of the speeds of the others. A common use of differentials is in motor vehicles, to allow the wheels at each end of a drive axle to rotate at different speeds while cornering. Other uses include clocks and Analog computer, analogue computers. Differentials can also provide a gear ratio between the input and output shafts (called the "axle ratio" or "diff ratio"). For example, many differentials in motor vehicles provide a gearing reduction by having fewer teeth on the pinion than the ring gear. History Milestones in the design or use of differentials include: * 100 BCE–70 BCE: The Antikythera mechanism has been dated to this period. It was discovered in 1902 on a shipwreck by Sponge diving, sponge divers, and modern research suggests that it used a differential gear to determine the angle between the ecliptic positions of the Sun and Moon, and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Truck
A truck or lorry is a motor vehicle designed to transport freight, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction, with a cabin that is independent of the payload portion of the vehicle. Smaller varieties may be mechanically similar to some automobiles. Commercial trucks can be very large and powerful and may be configured to be mounted with specialized equipment, such as in the case of refuse trucks, fire trucks, concrete mixers, and suction excavators. In American English, a commercial vehicle without a trailer or other articulation is formally a "straight truck" while one designed specifically to pull a trailer is not a truck but a " tractor". The majority of trucks currently in use are powered by diesel engines, although small- to medium-size trucks with gasoline engines exist in North America. Electrically powered trucks are more popu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Off-road Vehicle
An off-road vehicle (ORV), also known as an off-highway vehicle (OHV), overland vehicle or adventure vehicle, is a type of transportation specifically engineered to navigate unpaved roads and surfaces. These include trails, forest roads, and other low-traction terrains. Off-road vehicles are widely used in various contexts, from recreational activities to practical applications like agriculture and construction. Events such as the annual Dakar Rally, which spans multiple countries and challenges participants with diverse and extreme terrains, have brought significant attention to these vehicles. History One of the earliest modified off-road vehicles was the Kégresse track, a system for modifying cars developed by Adolphe Kégresse while working for Tsar Nicholas II of Russia between 1906 and 1916. The system employed a caterpillar track with a flexible belt instead of interlocking metal segments, which could be fitted to a conventional vehicle, turning it into a half-trac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engineering Ratios
Engineering is the practice of using natural science, mathematics, and the engineering design process to solve problems within technology, increase efficiency and productivity, and improve systems. Modern engineering comprises many subfields which include designing and improving infrastructure, machinery, vehicles, electronics, materials, and energy systems. The discipline of engineering encompasses a broad range of more specialized fields of engineering, each with a more specific emphasis for applications of mathematics and science. See glossary of engineering. The word ''engineering'' is derived from the Latin . Definition The American Engineers' Council for Professional Development (the predecessor of the Accreditation Board for Engineering and Technology aka ABET) has defined "engineering" as: History Engineering has existed since ancient times, when humans devised inventions such as the wedge, lever, wheel and pulley, etc. The term ''engineering'' is derived ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
