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A sliding pillar suspension is a form of independent front suspension for light cars. The stub axle and wheel assembly are attached to a vertical pillar or kingpin which slides up and down through a bush or bushes which are attached to the vehicle chassis, usually as part of transverse outrigger assemblies, sometimes resembling a traditional beam axle, although fixed rigidly to the chassis. [1] Steering movement is provided by allowing this same sliding pillar to also rotate.
Suspension is the system of tires, tire air, springs, shock absorbers and linkages that connects a vehicle to its wheels and allows relative motion between the two. Suspension systems must support both road holding/handling and ride quality, which are at odds with each other. The tuning of suspensions involves finding the right compromise. It is important for the suspension to keep the road wheel in contact with the road surface as much as possible, because all the road or ground forces acting on the vehicle do so through the contact patches of the tires. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different.
A stub axle or stud axle is either one of two front axles in a rear wheel drive vehicle, or one of the two rear axles in a front wheel drive vehicle. In a front wheel drive vehicle this axle is capable of angular movement about the kingpin for steering the vehicle.
The kingpin, also king-pin and king pin, is the main pivot in the steering mechanism of a car or other vehicle.
Sliding pillar independent suspension was first used by Decauville in 1898, the first recorded instance of independent front suspension on a motor vehicle. In this system, the stub axle carrying the wheel was fixed to the bottom of a pillar which slid up and down through a bush in a transverse axle fixed to the front of the chassis. The top of the pillar was fixed and pivoted on a transverse semi-elliptic leaf spring. This system was copied by Sizaire-Naudin a few years later.
Voitures automobiles Decauville was a French automobile maker, a subsidiary of Société Decauville, a company already famous for producing locomotives, located at Petit-Bourg, near Corbeil.
A leaf spring is a simple form of spring commonly used for the suspension in wheeled vehicles. Originally called a laminated or carriage spring, and sometimes referred to as a semi-elliptical spring or cart spring, it is one of the oldest forms of springing, appearing on carriages in England after 1750 and from there migrating to France and Germany.
Sizaire et Naudin was a French automobile manufacturer located on the northern side of central Paris, at 52 rue Victor-Hugo in Courbevoie, between 1903 and 1921.
In around 1904, the New Jersey inventor J. Walter Christie introduced a sliding pillar suspension system with vertical coil springs, which may be the inspiration for that later used by Lancia on its Lambda from around 1922. Lancia continued with sliding pillar suspension until the 1950s Appia. [2] In turn, this was copied for a single year by Nash on its unibody 600 model.
New Jersey is a state in the Mid-Atlantic region of the Northeastern United States. It is a peninsula, bordered on the north and east by the state of New York, particularly along the extent of the length of New York City on its western edge; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware River and Pennsylvania; and on the southwest by the Delaware Bay and Delaware. New Jersey is the fourth-smallest state by area but the 11th-most populous, with 9 million residents as of 2017, and the most densely populated of the 50 U.S. states; its biggest city is Newark. New Jersey lies completely within the combined statistical areas of New York City and Philadelphia and was the second-wealthiest U.S. state by median household income as of 2017.
John Walter Christie was an American engineer and inventor. He is best known for developing the Christie suspension system used in a number of World War II-era tank designs, most notably the Soviet BT and T-34 series, and the British Covenanter and Crusader Cruiser tanks, as well as the Comet heavy cruiser tank.
Lancia was an Italian automobile manufacturer founded in 1906 by Vincenzo Lancia as Lancia & C.. It became part of the Fiat Group in 1969; the current company, Lancia Automobiles, was established in 2007.
Sliding pillar suspension systems have also been used by several cyclecar manufacturers, the French maker Tracta, and in several prototype vehicles.
A cyclecar was a type of small, lightweight and inexpensive car manufactured in Europe and the United States between 1910 and the early 1920s. The purpose of cyclecars was to fill a gap in the market between the motorcycle and the car.
Tracta was a French car maker based in Asnières, Seine, that was active between 1926 and 1934. They were pioneers of front-wheel-drive vehicles.
In 1909 H.F.S. Morgan introduced a fundamentally similar system using a sliding stub axle on a fixed pillar, used first on Morgan Motor Company cyclecars, then on their cars up to the current time. The Morgan design is an inverted sliding pillar, as are most of the later designs; the pillar is attached to the chassis and the stub axle is carried by the sliding sleeve over this.
The Morgan Motor Company is a family-owned British motor car manufacturer that was founded in 1910 by Henry Frederick Stanley Morgan.
A drawback of the sliding pillar system is that the track changes with differential suspension movement, such as when one wheel rises over an obstacle (as can be seen in the diagram above). This is particularly an issue where the track is narrow (as for cyclecars) in relation to suspension travel. The effective track is the hypotenuse AC or AD of the triangle ABC, where AB is the fixed pillar spacing. However, many types of suspension, such as the swing axle have similar issues. Track variation is usually considered less important than changes in wheel camber, which is almost nonexistent in a sliding pillar system (see suspension geometry). [1]
The axle track in automobiles and other wheeled vehicles which have two or more wheels on an axle, is the distance between the centerline of two roadwheels on the same axle. In a case of the axle with dual wheels, the centerline in the middle of the dual wheel is used for the axle track specification.
A swing axle is a simple type of independent suspension designed and patented by Edmund Rumpler in 1903. This was a revolutionary invention in the automotive industry, allowing wheels to react to irregularities of road surfaces independently, and enable the vehicle to maintain a strong road holding. The first automotive application was the Rumpler Tropfenwagen, later followed by the Mercedes 130H/150H/170H, the Standard Superior, the Volkswagen Beetle and its derivatives, and the Chevrolet Corvair, amongst others.
Camber angle is the angle made by the wheels of a vehicle; specifically, it is the angle between the vertical axis of the wheels used for steering and the vertical axis of the vehicle when viewed from the front or rear. It is used in the design of steering and suspension. If the top of the wheel is farther out than the bottom, it is called positive camber; if the bottom of the wheel is farther out than the top, it is called negative camber.
This suspension system is rare, but was used most notably in the groundbreaking Lancia Aurelia coupe (1950–58).
