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A dual ball joint suspension uses a pair of arms, one in tension, one in compression, to replace a wishbone, in a MacPherson or SLA suspension. The outer end of each arm terminates in a ball joint, hence the name.
The two arms, the spindle, and the body, form a four-bar link. Use of the linkage at the lower suspension connection of either a MacPherson strut or a short long arms suspension readily gives an effective virtual ball joint outboard of the spindle, which is very useful for a suspension designer, allowing negative scrub radius whilst allowing the ball joints to move in and thus out of the way of the brakes. Some manufacturers use a double ball joint arm to replace both wishbones on a short long arms suspension. This provides further opportunity for optimising the geometry.
It is used on large cars such as the Lexus LS 460, BMW X5, Ford Territory, Genesis GV60 [1] , and General Motors' Zeta-derived models.
The extra ball joint adds weight and cost. It also increases steering friction, and the parasitic friction in the suspension. The geometry has some undesirable characteristics that need careful management, such as returnability from full lock when parking.
Camber angle is one of the angles made by the wheels of a vehicle; specifically, it is the angle between the vertical axis of a wheel 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.
The MacPherson strut is a type of automotive suspension system that uses the top of a telescopic damper as the upper steering pivot. It is widely used in the front suspension of modern vehicles. The name comes from American automotive engineer Earle S. MacPherson, who invented and developed the design.
The kingpin is the main pivot in the steering mechanism of a car or other vehicle.
A strut is a structural component commonly found in engineering, aeronautics, architecture and anatomy. Struts generally work by resisting longitudinal compression, but they may also serve in tension.
A multi-link suspension is a type of vehicle suspension with one or more transversal arms. A wider definition can consider any independent suspensions having three control links or more multi-link suspensions. These arms do not have to be of equal length, and may be angled away from their "obvious" direction. It was first introduced in the late 1960s on the Mercedes-Benz C111 and later on their W201 and W124 series.
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.
Independent suspension is any automobile suspension system that allows each wheel on the same axle to move vertically independently of the others. This is contrasted with a beam axle or deDion axle system in which the wheels are linked. "Independent" refers to the motion or path of movement of the wheels or suspension. It is common for the left and right sides of the suspension to be connected with anti-roll bars or other such mechanisms. The anti-roll bar ties the left and right suspension spring rates together but does not tie their motion together.
A double wishbone suspension is an independent suspension design for automobiles using two wishbone-shaped arms to locate the wheel. Each wishbone or arm has two mounting points to the chassis and one joint at the knuckle. The shock absorber and coil spring mount to the wishbones to control vertical movement. Double wishbone designs allow the engineer to carefully control the motion of the wheel throughout suspension travel, controlling such parameters as camber angle, caster angle, toe pattern, roll center height, scrub radius, scuff, and more.
A trailing-arm suspension, also referred to as trailing-link, is a form of vehicle suspension. In a motor vehicle it places one or more horizontal arms perpendicular to and forward of the axle on the chassis or unibody, which are connected to the axle or wheels with pivot joint(s). These are typically used on the rear axle or wheels of vehicles, but also found in both front and main landing gear of aircraft.
The Chapman strut is a design of independent rear suspension used for light cars, particularly sports and racing cars. It takes its name from, and is best known for its use by, Colin Chapman of Lotus.
An anti-roll bar is an automobile suspension part that helps reduce the body roll of a vehicle during fast cornering or over road irregularities. It links opposite front or rear wheels to a torsion spring using short lever arms for anchors. This increases the suspension's roll stiffness—its resistance to roll in turns.
In automotive suspension, a control arm, also known as an A-arm, is a hinged suspension link between the chassis and the suspension upright or hub that carries the wheel. In simple terms, it governs a wheel's vertical travel, allowing it to move up or down when driving over bumps, into potholes, or otherwise reacting to the irregularities of a road surface. Most control arms form the lower link of a suspension. Control arms play a crucial role in the suspension system of a vehicle. They help to keep the wheels aligned and maintain proper tire contact with the road, which is essential for safety and stability.
Torque steer is the unintended influence of engine torque on the steering, especially in front-wheel-drive vehicles. For example, during heavy acceleration, the steering may pull to one side, which may be disturbing to the driver. The effect is manifested either as a tugging sensation in the steering wheel, or a veering of the vehicle from the intended path. Torque steer is directly related to differences in the forces in the contact patches of the left and right drive wheels. The effect becomes more evident when high torques are applied to the drive wheels because of a high overall reduction ratio between the engine and wheels, high engine torque, or some combination of the two. Torque steer is distinct from steering kickback.
In an automobile, ball joints are spherical bearings that connect the control arms to the steering knuckles, and are used on virtually every automobile made. They bionically resemble the ball-and-socket joints found in most tetrapod animals.
A spherical bearing is a bearing that permits rotation about a central point in two orthogonal directions. Typically these bearings support a rotating shaft in the bore of the inner ring that must move not only rotationally, but also at an angle. It can either be a plain bearing or roller bearing.
Automotive suspension design is an aspect of automotive engineering, concerned with designing the suspension for cars and trucks. Suspension design for other vehicles is similar, though the process may not be as well established.
The Fiat C-platform was an automobile platform used in small family cars of the Fiat Group. The predecessors of the C-platform were the Type Three and Type Two platforms, and the successor is the new Compact platform which debuted in Alfa Romeo Giulietta in 2010.
Lever arm shock absorbers were the first form of hydraulic shock absorber or damper used for car suspension. They appeared in the 1930s and were most commonly used in the 1950s and 1960s, but were replaced by telescopic shock absorbers in the 1970s. One of the earliest patents for a hydraulic lever arm shock absorber was awarded in 1925 to Georges de Ram, who was already an established maker of friction disk shock absorbers.
Dual-pivot steering geometry is a geometric arrangement of linkages in the steering of a car designed to reduce or eliminate scrub radius by moving the pivot point of the king pin outboard, in order to improve steering precision and straight line stability.
Pull-rod suspension and push-rod suspension refer to a specialised type of automotive suspension system which is largely based on a double-wishbone system, incorporating elements of the commonly used MacPherson strut.