The MacPherson strut is a type of automotive suspension system that uses the top of the telescopic damper as the top steering shaft. It is widely used in modern vehicle front suspensions and is named for American automotive engineer Earle S. MacPherson, who originally invented and developed the design.
Video MacPherson strut
Histori
Earle S. MacPherson was appointed chief engineer of the Chevrolet Light Car project in 1945, to develop a smaller new car for the war market soon. This gave rise to the Chevrolet Cadet. In 1946, three Cadet design prototypes had been produced. This includes the first independent MacPherson strut suspension both front and rear. The Cadet project was canceled in 1947 and a disgruntled MacPherson was interested in joining Ford. The patent filed in 1947 ( US Pat. 2,624,592 for GM) and in 1949 ( US Pat. 2,660,449 for Ford), the 1949 patent cited the design by Guido Fornaca of FIAT in the middle of the year. -1920s. The strut suspension of the pre-war Scarab Stout could be the influence and struts of the long journey in today's famous plane gear gear. French Cottin-Desgouttes used a similar design, albeit with less sophisticated leaf springs, but the Cottin-Desgouttes front suspension was in turn inspired by the 1908 design of American engineer J. Walter Christie.
MacPherson designed the strut for all four wheels, but it is usually used for the front suspension only, where it provides the steering shaft as well as mounting the suspension for the wheels.
The first production car to use MacPherson struts is often listed incorrectly as French 1949 Ford Vedette, but developed before MacPherson with independent front suspension based on wishbones and top spring coil. Only in 1954, after the Vedette plant was purchased by Simca, did the revised Simca Vedette switch using the front struts.
Following the arrival of MacPherson at Ford, the first production car featuring the MacPherson struts feature was Ford Ford Consul in the 1950s and then Zephyr.
Maps MacPherson strut
Design
A MacPherson strut using wishbone, or a substantial compression link stabilized by a secondary link, that provides a mounting point for a hub carrier or wheel axle. This forearm system provides a lateral and longitudinal wheel location. The top of the rigid hub carrier remains to the bottom of the outer part of the proper strut; this slid up and down the inside, which extends straight up into the mounting on the vehicle's body shell. The line from the crushing crest to the bottom bone junction on the control arm gives the tilt of the steering axis. The strut axis can tilt inward from the steering axis at the bottom, to clean the tires; this keeps the bottom following the bow while driving.
To be truly successful, MacPherson strut requires the introduction of unity construction, as it requires large vertical spaces and strong mountain peaks, which can be provided unibodies, while benefiting them by distributing pressure. Strut will usually carry both coil springs in which the body is suspended and the shock absorbers, which are usually in the form of cartridges installed inside the strut (see coilover). Strut can also have steering arms built into the lower exterior. All assembly is very simple and can be assembled into one unit; also by eliminating the upper control arm, it allows for more width in the engine compartment, which is useful for smaller cars, especially with transverse mounted engines like most front wheel drive vehicles. This can be further simplified, if required, by replacing the anti-roll bar (torque rod) for the radius arm. For these reasons, it has become almost ubiquitous with low-cost producers. In addition, it offers an easy method for organizing suspension geometry.
Many modern applications replace the lower arm arm by wishbone. Optional anti-roll blades and if any are attached to a stick connected to a spring damper or with an elastomer ball or stem with a wishbone.
Profits and losses
Although this is a popular choice, due to its simplicity and low production cost, the design has some disadvantages in driving quality and car handling. Geometric analysis shows can not allow wheel vertical movement without some degree of camber angle change, sideways movement, or both. This is generally not regarded as a good handling as double wishbone or multi-link suspension, as it allows engineers less free to choose camber and roll center changes.
Despite these shortcomings, MacPherson's buffer settings are still used on high-performance cars including manufacturers like Porsche, Mercedes-Benz, and BMW.
The Porsche 911 to 1989 model year (964) used a similar strut design that had no coil springs, using a torsion rod suspension instead.
See also
- Chapman strut
- Coilover
- Double wishbone suspension
- Strut bar
References
External links
- MacPherson Geometry Calculator
Source of the article : Wikipedia
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