Subversion of your understanding of leaf spring
Leaf spring has been a lot of ordinary people as low-tech, can only be mixed in the role of truck trucks, but the fact is it? We come to tell you something different.
Is leaf spring really a symbol of backward technology?
I believe most people on the issue of the first answer is yes. But if you are more familiar with the following car, you will not think so: the Chevrolet Corvette.
It is a pure sense of the super sports car, the latest generation of ordinary version C7 Stingray has a 450hp (336kw), 609Nm strong output, can beat a big ticket more than double the number of its European rivals, and rely on the cylinder active closed And other technologies, daily fuel consumption can even be comparable to ordinary household cars. But many people do not know is that the rear suspension of the elastic element is the use of leaf spring.
C7 Stingray rear suspension assembly
Dare to use in the passenger car with leaf spring? This is also extremely rare in the car, not to mention the performance-oriented sports car. In fact, the official will be called "composite leaf spring." Although the leaf spring, but the use of monolithic composite materials, with the kind of truck on the multi-piece plate is completely different, in the structure, material, function, principle, design and other aspects of the demands Essential difference. Because different fixation methods and their own settings will lead to completely different force conditions; also can not simply compare the cost of the two springs, space and unsprung mass of these factors, because both with the material and the specific structure.
Truck longitudinal arrangement of leaf spring is mainly to load. The Corvette design has many subtleties: machining process becomes more simple, greater freedom of layout, reduce the occupancy of the compartment space, effectively reduce the quality of the unsprung to improve the suspension response, both anti-dumping A certain role of the rod. Even by different parts of the heat treatment, variable cross-section design, etc., than the average coil spring is easier to make changes in the variable stiffness characteristics, can be described as very sophisticated.
However, this design because of the changeable, involving a variable vertical stiffness, additional anti-roll characteristics of the dynamic characteristics of the engineers design, calibration requirements are very high; and variable cross-section of the plate design, heat treatment, etc. Requirements are very high. Moreover, this form of third-generation Corvette above the handed down, is the generic "unique skills", other manufacturers do not have the appropriate design history and experience, so very few of the same form of suspension, which is Why only Corvette can be so inventive reasons.
Corvette rear suspension of leaf spring
Steel plate rear suspension for general freight cars
Why do few passenger cars with leaf springs?
Said so marvelous, after all, is also a super-running things, why the passenger car with little leaf spring it? In fact, in the form similar to Corvette, ordinary passenger cars can also use such an arrangement to flow with leaf spring. Steel leaf spring stiffness change characteristics can be done and ordinary coil spring, and even change the more abundant multi-segment. The real reason to prevent the use of leaf springs for passenger cars is the following two reasons:
On the one hand, because the Corvette positioning is ultra-running, the demand for suspension travel is not large, so this layout is sufficient to meet its beating stroke of the wheel, but the ordinary passenger cars on the trip to most of the requirements, With the same way to layout, leaf spring travel is not enough; replaced by two groups of springs in charge of the left and right wheels, vertical layout of the words, the ground clearance as the truck as big as the family car, there is not enough space for the layout stand by;
Ordinary passenger cars and commercial vehicles, chassis space and rear suspension layout space comparison
On the other hand, because ordinary passenger cars on the cost control, research and development progress control and other "ground gas" factor considerations far greater than the special types of vehicles, so most of their suspension will choose to purchase; chassis R & In the form of saving time and cost of procurement; mature suppliers to provide the mainstream of the spring coil assembly is also a matter of course. No one in the economic class Jiajiao spend a lot of cost to do revolutionary innovation.
Of course, in the same cost, leaf spring still has its own limitations. For example, when using multiple springs, in addition to taking up volume than the coil spring, the friction between the sheet NVH performance also has a certain impact, and the use of passenger cars do not need to use the environment of heavy load . However, this can not be a reason for labeling a leaf spring with a "technically backward" label.
Therefore, the leaf spring is not only in the truck on the mix of the "third-rate role" can not simply equated with the representatives of backward technology, it is just a simple form of suspension, the same can have a high technical content. In the final analysis, can not say that because of the use of leaf spring, it is simply the conclusion of the quality of the vehicle itself, the actual suspension response and driving experience is the ultimate measure of good or bad standards. In fact, not only for the problem of leaf spring is the case, the problem of turbocharged, torsion beam rear suspension of the same problem. The most important point is: mechanical specifications and forms can not directly determine the merits of the car itself, the degree of advanced technology and adjust the orientation to decide.