COIL SPRING FOR VEHICLE SUSPENSION SYSTEM

Abstract

A coil spring includes an elongated body (10) formed by a plurality of continuous coils (21, 31), and the body (10) includes an upper section (20) and a lower section (30), wherein pitches (22) and coil angles (23) of the coils (21) in the upper section (20) are generally consistent to form an upright profile (24) for the upper section (20), and wherein pitches (32) and coil angles (33) of two or more coils (31) at a free end of the lower section (30) is differed from the pitches (22) and the coil angles (23) of the coils (21) in the upper section (20) to form a gradually curved profile (34) for the lower section (30).

Claims

1. A coil spring, comprising: an elongated body formed by a plurality of continuous coils; wherein the body includes an upper section and a lower section; wherein pitches and coil angles of the coils in the upper section are generally consistent to form an upright profile for the upper section; and wherein pitches and coil angles of two or more coils at a free end of the lower section is differed from the pitches and the coil angles of the coils in the upper section to form a gradually curved profile for the lower section.

2. The coil spring according to claim 1, wherein the upper section and lower section of the body form a generally J-shaped profile.

3. The coil spring according to claim 1, wherein the coil angles of the two or more coils at the free end of the lower section is greater than the coil angles of the coils in the upper section.

4. The coil spring according to claim 3, wherein each coil angle of the two or more coils at the free end of the lower section differs from each other.

5. The coil spring according to claim 1, wherein the pitches of the two or more coils at the free end of the lower section is greater than the pitches of the coils in the upper section.

6. The coil spring according to claim 5, wherein each pitch of the two or more coils at the free end of the lower section differs from each other.

7. A front vehicle suspension system comprising a coil spring as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] For the purpose of facilitating an understanding of the invention, there is illustrated in the accompanying drawing the preferred embodiments from an inspection of which when considered in connection with the following description, the invention, its construction and operation and many of its advantages would be readily understood and appreciated.

[0017] FIG. 1 illustrates conventional spring and existing shapes of coil springs which are known to control the lateral force, in accordance with the prior art.

[0018] FIG. 2 is a cross section diagram of a coil spring in J-shape configuration, in accordance with the general teachings of the present invention.

[0019] FIG. 3 is a diagram illustrating a comparison of lateral force generated absorption capability of an upper section and lower section of a J-shape spring and a conventional spring, in accordance with the general teachings of the present invention.

[0020] FIG. 4 is a comparison diagram between the J-shape coil spring and a conventional coil spring at uncompressed state and compressed state, in accordance with the general teachings of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0021] The invention will now be described in greater detail, by way of example, with reference to the drawings.

[0022] Referring to FIG. 2, a coil spring as illustrated therein comprises a body (10) of a generally cylindrical shape, being formed by a single wire that is wounded into a plurality of continuous coils (21, 31). The body (10) can be categorized into an upper section (20) having a plurality of helical coils (21) and a lower section (30) having a plurality of helical coils (31). The coil spring can be characterised by the following: (i) pitches (22) and coil angles (23) of the helical coils (21) in the upper section (20) are generally consistent with each other to form an upright profile (24) for the upper section (20); (ii) pitches (32) and coil angles (33) of two or more helical coils (31) at a free end of the lower section (30) is differed from the pitches (22) and the coil angles (23) of the helical coils (21) in the upper section (20) to form a gradually curved profile (34) for the lower section (30). When the upper section and lower section is combined, the body (10) forms a generally J-shape profile.

[0023] By way of example, the pitches (32) and coil angles (33) of the two or more helical coils (31) at the free end of the lower section is respectively greater than the pitches (22) and the coil angles (23) of the helical coils (21) in the upper section (20). In addition to that, the pitches (32) and coil angles (33) of the two or more helical coils in the lower section (20) may gradually increase in a direction towards the free end of the lower section (30) to form the curve profile (34) which gradually moves further away from an axial of the coil spring.

[0024] In operation, the coil spring is used in a vehicle suspension system. Preferably, the vehicle suspension system is a MacPherson strut type suspension system for front wheels of a vehicle. Nonetheless, it should be noted that the coil spring can also be applied in any other vehicle suspension systems which absorption of lateral force is required. In the example of the MacPherson strut type suspension system, the coil spring is disposed at a position of a shock absorber that surrounds the shock absorber, and the coil spring is being held in place by a pair of collars on a strut. The strut is angled and thereby giving rise to lateral forces which required to be damped by the shock absorber. The coil spring absorbs the lateral force in the form of compressed energy which is later dissipated by the shock absorber.

[0025] Characteristics of the J-shape coil spring in terms of load axis formed by the lateral force generated is illustrated in FIG. 3. It produces higher lateral force significantly compare to a conventional spring. The lateral force generated at the lower section (30) is much higher than upper section (20) of the coil spring. Most of the passenger vehicles nowadays require higher lateral force at the lower section due to improvement made on the positioning of the suspension system to fit with the limited enveloping space.

[0026] As shown in FIG. 4, the J-shape coil spring in both compressed state and uncompressed state has an overall width which is almost identical to a coil spring in a straight configuration. As a result, the J-shape coil spring is capable of generating greater lateral force and maintaining even gap between coils especially at the lower section (20). Thus, it does not occupy more space than the conventional coil spring. The helical coils (21, 31) in the compressed state are also in even gap and no interference between coils. It is a design rule to avoid such interference during stroke to avoid continuous knocking between coils which will affect the coil spring life.

[0027] The present disclosure includes as contained in the appended claims, as well as that of the foregoing description. Although this invention has been described in its preferred form with a degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangements of parts may be resorted to without departing from the scope of the invention.