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1 McPherson suspension
Origin:
McPherson suspension is in response to a front-engine front-drive (ff) of the vehicle occurs born. ff models requires not only the engine to be placed horizontally, but also to increase transmissions, differentials, drive mechanism, steering, front suspension the previous space had to be compressed and sharply deleted, so engineers was to design a space-saving, low cost the McPherson suspension in order to meet the demand for cars. Now general car before and after the suspension are substantially McPherson or variations.
McPherson (mcpherson) is a personal name. He is a Illinois man, born in 1891. After graduation he worked in Europe for many years engaged in aircraft engine and added GM’s engineering center in 1924. 1930s, GM’s Chevrolet company wants to design a really small car, it is the chief architect of McPherson. He was very interested in designing small cars, the goal is to control the quality of this four cars in less than 0.9 tons, control wheelbase less than 2.74 m, the design is the key to suspension. McPherson time before a change of the leaf spring and torsion bar spring suspension prevailing manner, creatively combine shock absorbers and coil springs mounted on the front axle. Practice has proved that this form of suspension structure is simple, small footprint, and excellent maneuverability.
Applications:
McPherson switched to Ford, 1950 Ford in the UK, a subsidiary of the production of two cars, is the world’s first use of McPherson suspension goods vehicles. McPherson suspension due to the simple structure, superior performance reasons, was hailed as a classic of design experts. McPherson suspension in front of the car on the wide application of the suspension is unmatched by the other. Large BMW M3, Porsche 911 high-performance vehicles such as small Fiat STILO, FORD FOCUS, even domestic Hafei van MacPherson front suspension design is used.
Advantages:
in the end what is the reason to make McPherson suspension so widely used? What are the performance characteristics of this suspension in the end there is so common it? Let’s start with its design structure to understand from it.
McPherson suspension usually consists of two basic components: A shaped strut dampers and carriage arm. It is called the shock absorber strut is because in addition to the damping action as well as supporting the entire body, his structure is very compact, integrated damper and the damper spring, composed of a spool can be moved up and down; subiculum a shaped arm is typically designed to provide some lateral support to the wheel forces and withstand the full longitudinal direction of stress. All impact and weight of the entire car body in motion on the wheel subjected to bear against the two components. So McPherson is one of the biggest design feature is simple structure, a simple structure can bring direct benefits that is two: light weight and small hanging space. We know that the car belongs to hang moving parts, moving parts lighter, then the suspension response and rebound velocities will be faster, so the suspension damping capacity of the stronger; and to reduce the unsprung mass also means to reduce the unsprung mass, so in the case of a certain body weight, comfort is also better. The immediate benefit is to bring a small footprint designers can be arranged at a larger engine in the engine compartment, and the placement of the engine can be arbitrary. In the mid-sized car to set aside large engine, the car can be put down in a small and medium-sized engines, so that matching various engine more flexible.
Disadvantages:
Johnson said the advantages of such a Duo Maifu suspension, should also talk about the shortcomings. McPherson is also because the structure is too simple, resulting in limited suspension stiffness. Since only by McPherson suspension lower arm and shock absorber strut bracket to bear a strong impact of the wheel, so prone to geometric distortion. Such modification to reflect the driving experience is that the driver will feel significantly inferior body stability. Whether it is the turn roll, or nose dive brakes, they are very obvious. Of course, the designers also want a lot of ways to solve the stability problem. We often hear stabilizer, anti-roll bars, and the like are used to improve the balance bar Maifu Johnson suspension geometry and rigidity member lateral stability.
the stabilizer is a torsion bar spring has a rigidity, he is connected to the spool and the left and right lower suspension arm or a damper bracket. When both the left and right suspensionWhen the road is bumpy, while both sides of the vertical movement of the suspension, the stabilizer bar twisting does not occur; when the vehicle is cornering, the suspension subjected to the outside due to the large forces, the occurrence of a certain body roll. At this time, the outer suspension contraction, relaxation suspended inside, then the stabilizer twist occurs, a certain elastic force, prevent the vehicle from rolling. Thereby improving the running stability of the vehicle. Add the support bar member, the object can be achieved while improving the longitudinal stiffness of the suspension.
However, the stabilizer bar is increased simply by increasing the performance is limited to improve the stability and rigidity of the suspension geometry using various stabilizer bar to some extent from the design. If you are to solve these problems, we must change the entire suspension geometry, the multi-link double wishbone suspension and high-performance suspension became a representative. McPherson suspension stability and rigidity in addition to the multi-link in less than in the durability can not be compared with the multi-link suspension. Since McPherson suspension damper strut need to withstand lateral forces, while also serve the purpose of reducing the vertical motion of vibration, shock absorber strut so that friction is very uneven, prone to wear caused by the damper seal to reduce leakage of hydraulic oil damping effect.