Suspension link

Last updated February 25, 2019

In automotive suspensions, a suspension link, control link or link is a suspension member, that attaches at only two points. One point being the body or frame of the vehicle and the other point attaching to the knuckle, upright, axle or another link. The link pivots on either a bushing or a ball joint at each attachment point. A link differs from a control arm because it can only control one of the degrees of freedom by itself.

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 bushing or rubber bushing is a type of vibration isolator. It provides an interface between two parts, damping the energy transmitted through the bushing. A common application is in vehicle suspension systems, where a bushing made of rubber separates the faces of two metal objects while allowing a certain amount of movement. This movement allows the suspension parts to move freely, for example, when traveling over a large bump, while minimizing transmission of noise and small vibrations through to the chassis of the vehicle. A rubber bushing may also be described as a flexible mounting or antivibration mounting.

In an automobile, ball joints are spherical bearings that connect the control arms to the steering knuckles. They are used on virtually every automobile made and work similarly to the ball-and-socket design of the human hip joint.

In the attached photo of a 5-link live axle suspension, the different types of links can be seen. These links work in tandem with the coil springs, dampers, and sway bar to control all six degrees of freedom of the axle. The upper links (orange) and the lower links (yellow) work in tandem to control the pitch, yaw and the fore and aft movement (surge). The panhard rod (green) controls the left and right movement (sway). While the springs and dampers (not shown) control the up and down movement (heave) and the roll is controlled by the sway bar (also not shown).

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. They are made of an elastic material formed into the shape of a helix which returns to its natural length when unloaded.

A shock absorber is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy which is then dissipated. Most shock absorbers are a form of dashpot.

Six degrees of freedom (6DoF) refers to the freedom of movement of a rigid body in three-dimensional space. Specifically, the body is free to change position as forward/backward (surge), up/down (heave), left/right (sway) translation in three perpendicular axes, combined with changes in orientation through rotation about three perpendicular axes, often termed yaw, pitch, and roll.

It takes a minimum of two links per wheel in a MacPherson strut-style suspension and a minimum of three links per wheel in a multi-link suspension.

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 and is named for American automotive engineer Earle S. MacPherson, who originally invented and developed the design.

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 wider definition considers 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.

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A torsion bar suspension, also known as a torsion spring suspension, is any vehicle suspension that uses a torsion bar as its main weight-bearing spring. One end of a long metal bar is attached firmly to the vehicle chassis; the opposite end terminates in a lever, the torsion key, mounted perpendicular to the bar, that is attached to a suspension arm, a spindle, or the axle. Vertical motion of the wheel causes the bar to twist around its axis and is resisted by the bar's torsion resistance. The effective spring rate of the bar is determined by its length, cross section, shape, material, and manufacturing process.

Leaf spring simple form of spring, mostly used for the suspension of cars

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.

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 – movement on one side affects the wheel on the other side. "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.

In automobiles, a double wishbone suspension is an independent suspension design 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, sometimes referred as trailing-link is a vehicle suspension design in which one or more arms are connected between the axle and a pivot point. It is typically used on the rear axle of a motor vehicle. A leading arm, as used on the Citroën 2CV and the M422 Mighty Mite, has an arm connected between the axle and the chassis. It is used on the front axle.

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 a part of many automobile suspensions that helps reduce the body roll of a vehicle during fast cornering or over road irregularities. It connects opposite (left/right) wheels together through short lever arms linked by a torsion spring. A sway bar increases the suspension's roll stiffness—its resistance to roll in turns, independent of its spring rate in the vertical direction. The first stabilizer bar patent was awarded to Canadian inventor Stephen Coleman of Fredericton, New Brunswick on April 22, 1919.

A beam axle, rigid axle or solid axle is a dependent suspension design, in which a set of wheels is connected laterally by a single beam or shaft. Beam axles were once commonly used at the rear wheels of a vehicle, but historically they have also been used as front axles in rear-wheel-drive vehicles. In most automobiles, beam axles have been replaced by front and rear independent suspensions.

Corvette leaf spring commonly refers to a type of independent suspension that utilizes a fiber-reinforced plastic (FRP) mono-leaf spring instead of more conventional coil springs. It is named after the Chevrolet Corvette, the American sports car for which it was originally developed and first utilized. A notable characteristic of this suspension configuration is the mounting of the mono-leaf spring such that it can serve as both ride spring and anti-roll spring. In contrast to many applications of leaf springs in automotive suspension designs, this type does not use the spring as a locating link. While this suspension type is most notably associated with several generations of the Chevrolet Corvette the design has been used in other production General Motors cars, as well as vehicles from Volvo Cars and Mercedes-Benz. Fiat produced cars with a similar configuration, using a multi-leaf steel spring in place of the FRP mono-leaf spring.

Bicycle suspension is the system, or systems, used to suspend the rider and bicycle in order to insulate them from the roughness of the terrain. Bicycle suspension is used primarily on mountain bikes, but is also common on hybrid bicycles.

Bump steer or roll steer is the term for the tendency of the wheel of a car to steer itself as it moves through the suspension stroke. It is typically measured in degrees of steer per metre of upwards motion or degrees per foot.

The twist-beam rear suspension is a type of automobile suspension based on a large H or C shaped member. The front of the H attaches to the body via rubber bushings, and the rear of the H carries each stub-axle assembly, on each side of the car. The cross beam of the H holds the two trailing arms together, and provides the roll stiffness of the suspension, by twisting as the two trailing arms move vertically, relative to each other.

Jaguar's independent rear suspension (IRS) unit has been a common component of a number of Jaguar production cars since 1961, passing through two major changes of configuration up to 2006 and last used in the Jaguar XK8 and Aston Martin DB7. This article concentrates on the first generation Jaguar IRS, which firmly established the marque's reputation for suspension sophistication, combining as it did smooth ride with excellent roadholding and low levels of noise, vibration, and harshness (NVH). The two generations overlap in time due to their being used in both full size and sports models that were updated at different times. The modern S-Type, XF, XJ and XK models use a Jaguar-designed unit for the Ford DEW98 platform.

Transverse leaf spring front suspension is a type of automotive front suspension, whose usage is most well known in Ford Motor Company products from 1908 to 1948. "Suicide front axle" is a term that has been used for it.

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Suspension link

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