The Steering Rack of a motor vehicle or rack and pinion is a linear actuator that comprises a pair of gears which convert rotational motion into linear motion. A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit toque. A gear called "the pinion gear" which works similarly to a “worm gear” which engages teeth on a “linear gear" or bar with teeth along one side, called "the rack". When the steering wheel shaft is turned and rotational motion is applied to the pinion and this worming type of motion is what causes the rack to move to the left side or the right side of the pinion. Like other gear arrangements, a pinion can reduce rotational speed or allow higher torque to be transmitted. This motion translates the rotational motion of the pinion into the linear motion of the rack thereby turning the wheels of the vehicle in the direction of the steering wheel. The steering rack is mostly power assisted by the hydraulic power steering pump which enables easy turning of the vehicles wheels, especially when stationary or when moving slowly.

The rack and pinion arrangement is generally found in the steering mechanism of motor vehicles. The use of a variable rack, which still uses a normal pinion, was invented by Arthur Bishop to improve vehicle response and steering at high speeds. He created a specialized version of a net-shape warm press forging process to manufacture the racks to their final form, thus eliminating any subsequent need to machine the gear teeth simplifying the manufacturing process considerably. For every pair of conjugate involute profiles, there is a basic rack. This basic rack is the profile of the conjugate gear of infinite pitch radius.

In early 20th century automobiles prior to the introduction of power steering had the problems of direct steering forces transmitted through the wheels and steering mechanisms that were used to steer the vehicle. The effect of a flat or blowout on one of the front wheels would tend to pull the steering mechanism toward the side with the flat tire. The employment of a worm screw reduced this effect. Further development of the worm drive employed recirculating ball bearings to reduce frictional forces, allowing some of the steering force to be felt in the wheel as an aid to vehicle control and greatly reducing wear.

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Power Steering helps drivers steer vehicles by augmenting steering effort of the steering wheel. Most power steering systems work by using a hydraulic system to steer the vehicle's wheels. It does all this by adding controlled energy to the steering mechanisms steering rack or steering box, so the driver needs to provide only modest effort, regardless of the road conditions. Power steering especially helps when a vehicle is stopped or moving very slowly.

Power steering systems for cars augment steering effort via an actuator which is a hydraulic cylinder, which is part of a servo system. These systems have a direct mechanical connection between the steering wheel and the linkage that steers the wheels. This means that power steering system failure still permits the vehicle to be steered using great amounts of manual effort.

Other power steering systems have no direct mechanical connection to the steering linkage as they require power for example large trucks and abnormal construction vehicles. Systems of this kind, with no mechanical connection, are sometimes called "drive by wire". In this context, "wire" refers to electrical cables that carry power and data to servos that are used to move in one direction or the other.

In other power steering systems, electric motors provide the assistance instead of hydraulic systems. As with hydraulic types, power to the actuator motor is controlled by the rest of the power steering system.

The hydraulic pressure for a steering system typically comes from a rotary vane pump, the power steering pump driven by the vehicle's engine. A double-acting hydraulic cylinder applies a force to the steering gear, which pushes the wheels to the left or the right, in turn steering the wheels of the vehicle.

One design for measuring the torque applied to the steering wheel has a torque sensor or a torsion bar at the lower end of the steering column. As the steering wheel rotates, so does the steering column, as well as the upper end of the torsion bar. Since the torsion bar is relatively thin and flexible, and the bottom end usually resists being rotated, the bar will twist by an amount proportional to the applied torque. The difference in position between the opposite ends of the torsion bar controls a valve. The valve allows fluid to flow to the cylinder which provides steering assistance and the greater the "twist" of the torsion bar, the greater the force.

Since the hydraulic pumps are positive-displacement type, the flow rate they deliver is directly proportional to the speed of the engine. A pressure relief valve prevents a dangerous build-up of pressure when the hydraulic cylinder's piston reaches the end of its stroke. Pressure build up would be undesirable if the pump produced more pressure at high speeds of engine rotation to low speeds so a restricting orifice and flow-control valve direct some of the pump's output back to the hydraulic reservoir at high engine speeds.

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The automotive alternator is used in modern cars, trucks and most automobiles where power needs to be generated to power lights and other electrical parts of a motor vehicle. The alternator is required to charge the battery and to power the electrical system when its engine is running. Until the 1960s, automobiles used DC dynamo generators. With the availability of affordable silicon diode rectifiers, alternators became the modern choice of power. Alternators have several advantages over direct-current generators in that they are lighter and cheaper. They use slip rings which greatly extended brush life. The brushes in an alternator carry only excitation current, a small fraction of the current carried by the brushes of a DC generator, which carry the generator's entire output. A set of rectifiers is required to convert AC to DC power.

Automotive alternators are usually belt driven at 2-3 times crankshaft speed. The alternator runs at various RPM which varies the frequency and since it is driven by the engine the alternating current is rectified to direct current.

Automotive alternators require a voltage regulator which operates by modulating the small field of current in order to produce a constant voltage at the battery terminals. Early designs used a discrete device mounted elsewhere in the vehicle between 1960 and 1970. Intermediate designs were incorporated the voltage regulator into the alternator housing between 1970 and 1990. Modern vehicles today mostly regulate voltage via the electronic or engine control unit or abbreviated the ECU. In recent years, alternator regulators are linked directly to the vehicle's computer system and various factors including air temperature obtained from the intake air temperature sensor, battery temperature sensor and engine load are evaluated in adjusting the voltage supplied by the alternator.

The field windings are initially supplied power from the battery via the ignition switch and "charge" warning red light indicator on the dashboard instrument cluster. Once the engine is running and the alternator is generating power, a diode feeds the field current from the alternator main output equalizing the voltage across the red light warning indicator which goes then goes off on the instrument cluster. Some warning indicator circuits are equipped with a resistor in parallel with the lamp that permit excitation current to flow if the warning light burns out. The driver should check that the warning indicator is on when the engine is not running or before starting the engine otherwise, there might not be any indication of a failure of the belt which may also drive water pump.

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The Car as we know it today is also referred to as an automobile, auto car, motor car is a wheeled chassis with an engine mounted to it used for the transportation of passengers and their goods. In the beginning of the 1920’s the term motorcar was also used in the context of electrified rail systems to denote a car which functions as a small locomotive for passengers and their goods.

Around the world, there were about 800 million cars and light trucks on the road in 2006 and the engines of these automobiles burn over one billion cubic meters of petrol and diesel fuel every year, as China alone puts out 14000 cars onto the roads each day.

In 1807 Nicephore Niepce and his brother Claude probably created the world's first internal combustion engine, but they chose to install it in a boat on the river Saone in France.

Henry Ford was an American industrialist, the founder of the Ford Motor Company, and sponsor of the development of the assembly line technique of mass production. His introduction of the Model T automobile revolutionized transportation and American industry.

Karl Benz is generally is acknowledged as the inventor of the modern day motor car. An automobile powered by his own four stroke petrol engine was built in Germany in 1885. It was an integral design, without the adaptation of other existing components, and included several new technological elements to create a new concept. He began to sell his production cars in 1888.

In 1879, Benz was granted a patent for his first engine. Many of his other inventions made the use of the internal combustion engine feasible for powering a vehicle. His first Motorwagen was built in 1885, and he was awarded the patent for its invention as of his application on January 29, 1886. Benz began promotion of the vehicle on July 3, 1886, and about 25 Benz vehicles were sold between 1888 and 1893. They also were powered with four-stroke engines of his own design

In 1896, Benz designed and patented the first internal-combustion flat engine, called The Boxermotor. During the last years of the nineteenth century, Benz was the largest automobile company in the world with 572 units produced in 1899.

The first design for an American automobile with a gasoline internal combustion engine was made in 1877 by George Selden of New of New York. After a delay of sixteen years and a series of attachments to his application, on November 5, 1895, Selden was granted a United States patent for a two-stroke automobile engine. His patent was challenged by Henry Ford and overturned in 1911.

If you are looking 4 spares for your car or light commercial vehicle Looking 4 Spares is a Free Parts Locator Service that will send your request out to all participating Scrapyards & Parts Suppliers Nationwide. Whoever has the parts will call you.

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