GB2241765A

GB2241765A - Suspension strut

Info

Publication number: GB2241765A
Application number: GB9104826A
Authority: GB
Inventors: Guenther Handke
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1990-03-09
Filing date: 1991-03-07
Publication date: 1991-09-11
Anticipated expiration: 2011-03-07
Also published as: FR2659279A1; FR2659279B1; GB2241765B; GB9104826D0; DE4007488A1

Abstract

A suspension strut has a spring carrier (8, 8a) supporting the end (2a, 2b) of a helical compression spring (2). A catching ring (7, 107) is located between the spring carrier and the end of the helical compression spring. This catching ring may comprise a metallic core (4, Fig. 2) covered with rubber. <IMAGE>

Description

0 7_ 2. 4 - v SUSPENSION STRUT Suspension struts for vehicles comprise an

oscillation damper having a container, a piston rod axially movable with respect to the container and a container-side spring carrier member axially fixed to the container. The container is connected to a portion of respective wheel supporting means, and the piston rod is connected to a portion of a respective vehicle body work. A helical compression spring is under prestress supported by one of its ends on the containerside spring carrier member and by the other of its ends on a body-work-side spring carrier member which is substantially stationary with respect to the body work.

It is necessary to center the helical compression spring with respect to the respective spring carrier members, as lateral forces would otherwise result in a lateral displacement of the helical compression spring with respect to the spring carrier members. This risk occurs particularly, if the axis of the helical compression spring is not coincident with the axis of the oscillation damper, and the risk.'s especially high, when the helical compression spring breaks. In this latter case, there might even occur a contact between the helical compression spring and the respective vehicle Spring catching means are known e. g. from German Offenlegungsschrift 34 42 108, corresponding to U. S. Patent No. 4,655,439. The known construction representing a number of further known constructions suffers from difficulties in providing the necessary protection against corrosion. One has provided zinc coatings on the spring carrier members. This resulted in considerable problems, if the spring carrier members were welded to the oscillation damper container. A further disadvantage of the known construction was a direct metallic contact between the helical compression spring and the respective carrier members. Unacceptable noise resulted from such direct metallic contact. One has also tried to provide rings between the helical compression spring and the respective spring carrier member. With such a solution, it was necessary to provide the spring carrier member with a drawnup retainer edge. Such a drawn-up retainer edge required a high degree of reshaping and resulted also in a relatively great.mass of the respective spring carrier member.

It is a primary object of the present invention to provide a suspension strut, in which the helical compression spring is secured against lateral displacement and in-which this security against lateral displacement is obtained by simple and inexpensive components which are easy to be assembled.

A further object of the invention is to avoid corrosion, and a still further object is to prevent wear and noises which could result from metallic contact.

According to the invention there is provided a suspension strut for a vehicle comprising an oscillation damper, said oscillation damper having an axis, a container, a piston rod axially movable with respect to said container and a container-side spring carrier member axially fixed to said container, said container being connectable to a portion of respective wheel supporting means and said piston rod being connectable to a portion of a respective vehicle body work, said suspension strut further comprising a helical compression spring having an axis and being supportable by one of its ends on said container-side spring carrier member and supportable by the other of its ends on a body-work-side spring carrier member substantially stationary with respect to said body work, said helical compression spring being accommodated by at least one end thereof within spring 1 i - i catching means allocated to the respective one of said spring carrier members, characterised by said spring catching means comprising catching ring means produced separately from and carried by the respective spring carrier member, said catching ring means comprising an annular metallic core member and an insulating layer covering at least part of said annular metallic core member, said catching ring means being radially centred with respect to the respective spring carrier member.

The insulating layer may be restricted to the most sensitive parts of the surface of the metallic core. Preferably, however, the insulating layer covers the complete surface of said annular metallic core member.

The most important function of the insulating layer is corrosion protection. Therefore, the layer may be a corrosion protective layer such as obtained by lacquering, as electrostatic lacquering, electrophoretic lacquering or cataphoretic lacquering. It has been found that such a lacquering is completely adequate for the anti-corrosion protection of the catching ring means. The spring carrier members may also be lacquered according to one of the abovementioned methods. So, there is no problem when welding a spring carrier member to a container tube or the like.

1 1 In order to obtain a suspension strut granting higher comfort, the insulating layer may be a noise and wear suppressing layer. The anticorrosive, antiwear and antinoise function may be combined e. g. in that the insulating layer is a layer containing at least one of rubber, rubber-like materials and plastics material.

Best results are obtained, if the respective end o f said helical compression spring is in engagement with said insulating layer.

According to a preferred embodiment of the invention, the catching ring means have a substantially L-shaped or U-shaped cross-sectional configuration with a support limb supporting a respective end of said helical compression spring and a radially outer catching limb adjacent a radially outer face of the respective end of said helical compression spring. For a good protection against lateral displacement of the helical compression spring even in case of rupture of the spring, the catching limb should have a height-as measured above a spring support sole face of said support limb - which height corresponds at least to the wire diameter of said helical compression spring. Preferably, the height of the catching limb is such as to completely cover a terminal winding of the respective end of said helical compression spring in radial direction.

The catching ring means may be radially centered on the respective springcarrier member by a radially inner centering face of said catching ring means engaging a radially outer centering face of the respective spring carrier member.

The catching ring means may be simply applied to the respective spring carrier member and can be held in position by the prestress of the helical compression spring. For more positively fastening the catching ring means on the respective spring carrier members, at least one of the radially inner and radially outer centering faces may be conically divergent in a direction of application of said catching ring means to the respective spring carrier member. So, the catching ring means are frictionally engaged with the respective centering face of the.respective spring carrier member. This frictional engagement is obtained without complicated assembling measures, particularly if the catching ring means engage the centering face of the spring carrier member by an elastic or plastic coating layer.

As a consequence of the above described preferred embodiment, drawn-up edge portions of the spring carrier member may be avoided. In other words: the respective spring carrier member may have a carrier face substantially perpendicular to the axis of said helical compression spring for engagement with a bottom face of said catching ring means, said carrier face being open in radially outward direction.

If the drawn-up edge of the spring carrier can be avoided, the spring carrier member can be press-shaped from a noncircular blank of sheet metal, e. g. a four-cornered blank of sheet metal, which is easily available and avoids metal waste.

The above-mentioned core member may again have a substantially L-shaped or U-shaped cross-sectional configuration with a support limb following said support limb of said catching ring means and a radially outer catching limb following said radially outer catching limb of said catching ring means.

- 6 The catching ring means may be allocated to the container- side spring carrier member or to the body-work-side spring carrier member or to both of them.

A particular advantage of the present invention is that the catching ring means may be simply laid upon the respective spring carrier member and need not be fastened thereto. The fastening function is fulfilled by the helical compression spring itself.

Alternatively, the catching ring means may be also formed without metallic core, e. g. from plastic or ceramic material.In such case again, the above-mentioned L-shaped or U-shaped configuration is possible and the positioning may occur as described above.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed,; hereto and forming a part of the disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

The invention will be explained in greater detail hereinafter with reference to an embodiment shown in the accompanying drawings in which Fig. 1 shows a suspension strut, i. e. a combination of a shock absorber and a helical compression spring; Fig. 2 shows catching ring means in combination with a spring carrier member and - i 1 1 1 Fig. 3 shows an annular metallic core member completely covered by an insulating layer.

In Fig. 1, one can see a usual shock absorber with a container 1 and a piston rod 10. The container is provided at its lower end 12 with a bracket which is a part.of a wheel suspension. The upper end of the piston rod 10 (not shown) is adapted for being connected to the body work 14 of a motor vehicle. A helical compression spring 2 is inserted under prestress between a container-side spring carrier member 8 and a body- work-side spring carrier member 8a. The spring carrier member 8 is in this embodiment axially fixed with respect to the container by a support ring 16 through a ball bearing 18. It is to be noted, however, that the spring carrier member can also be welded to the container tube 1. A catching ring unit 7 is provided between the lower end 2a of the helical compression spring 2 and the lower spring carrier member 8. This catching spring unit 7 is shown in more detail in Figs. 2 and 3. The catching ring unit 7 comprises an L-shaped core member 4 having a support limb 4a and a catching limb 4b. This L-shaped core member is coated with a layer 5 of corrosion protective material so that the complete catching ring unit 7 comprises a supporting limb 7a accommodating the limb 4a and a limb 7b accommodating the limb 4b. The sole face of the support limb 7a is designated by 6. From Fig. 2 one can see that the lower terminal winding 2a of the helical compression spring 2 is embedded in a groove 20 defined by the coating 5.

Moreover, one can see from Fig. 2 that a bottom face 7al of the support limb 7a is seated on a carrier face 22 of the spring carrier member 8. The sole face 6 has a height H2 above the bottom face 7al, and the catching limb 7b has a height H 1 above this sole face 6 such that the lower terminal winding 2a is completely surrounded. The catching ring unit 7 has a conical centering face 3 which engages a conical centering face 24 of the spring carrier member 8 -1 From Fig. 1, it is to be seen that a similar or preferably identic catching ring unit 107 is provided at the upper spring carrier member 8a for supporting the upper end 2 b of the helical compression spring 2.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

The reference numerals in the claims are only used for facilitating the understanding and are by no means restrictive.

i - 9

Claims

CLAIMS:

1. A suspension strut for a vehicle comprising an oscillation damper (1, 10), said oscillation damper (1,10) having an axis, a container (1), a piston rod (10) axially movable with respect to said container (1) and a container-side spring carrier member (8) axially fixed to said container (1), said container (1) being connectable to.a portion (12) of respective wheel supporting means and said piston rod (10) being connectable to a portion (14) of a respective vehicle body work, said suspension strut further comprisingl!a helical.compression spring (2) having an axis and being supportable byone (2a) of its ends (2a,2b) on said container-side spring carrier member (8) and supportable by the other (2b) of its ends (2a,2b) on a bodrk-side spring carrier member (8a) substantially stationary with respect to said bodywork (14), said helical compression spring (2) being accommodated by at least one end (2a) thereof within spring catching means (7) allocated to the respective one (8) of said spring carrier members (8,8a), characterized by said spring catching means (7,107) comprising catching ring means (7,107) produced separately from and carried by the respective spring carrier member (8,8a), said catching ring means (7,107) comprising an annular metallic core member (4) and an insulating layer (5) covering at least part of said annular metallic core member (4), said catching ring means (7,107) being radially centered with respect to the respective spring carrier member (8,8a).

A suspension strut as claimed in claim 1, said insulating layer (5) covering the complete surface of said annular metallic core member (4).

3. A suspension strut as claimed in claim 1 or 2, said insulating layer (5) being a corrosion protective layer.

A suspension strut as claimed in one of claims 1 - 3, said insulating layer (5) being a noise and wear suppressing layer.

A suspension strut as claimed in one of claims 1- 4, said insulating layer (5) being a layer containing at least one of rubber, rubber-like materials and plastics material.

6. A suspension strut as set forth in one of claims 1 - 5, the respective end (2a,2b) of said helical compression spring (2) being in engagement with said insulating layer (5).

A suspension strut as set forth in one of claims 1 - 6, said catching ring means (7,107) having one of a substantially L-shaped and a substantially U-shaped cross-sectional configuration with a support limb (7a) supporting a respective end (2a,2b) of said helical campression spring (2) and a radially outer catching limb (7b) adjacent a radially outer face of the respective end (2a,2b) of said helical compression spring (2).

A suspension strut as claimed in claim 7, said catching limb (7b) having a height (H 1 as measured above a spring support sole face (6) of said support limb (7a) - which height (H 1) corresponds at least to the wire diameter of said helical canpression spring (2).

A suspension strut as set forth in claim 8, said height (H 1) of said catching limb (7b) being such I 1 i as to completely cover a terminal winding (2a) of the respective end of said helical compression spring (2) in radial direction.

10. A suspension strut as set forth in one of claims 1 - 9, said catching ring means (7,107) being radially centered on the respective spring carrier member (8,8a) by a radially inner centering face (3) of said catching ring means (7,107) engaging a radially outer centering face (24) of the respective spring carrier member (8,8a).

11. A suspension strut as set forth in claim 10, at least one of said radially inner and radially outer centering faces (3,24) being conically divergent in a direction of application of said catching ring means (7, 107) to the respective spring carrier member (8,8a).

12. A suspension strut as set forth in one of claims 1 - 11, the respective spring carrier member (8,8a) having a carrier face (22) substantially perpendicular to the axis of said helical compression spring (2) for engagement with a bottom face Pal) of said catching ring means (7), said carrier face (22) being open in radially outward direction.

13. A suspension strut as set forth in claim 12, the respective spring carrier member (8,8a) being press-shaped from a non-circular blank of sheet metal.

14. A suspension strut as set forth in claim 13, said non-circular blank being a four-cornered blank.

A suspension strut as set forth in one of claims 7 - 14, said core member (4) having one of a substantially 1 L-shaped and a substantially U-shaped cross-sectional configuration with a support limb (4a) following said support limb (7a) of said catching ring means (7) and a radially outer catching limb (4b) following said radially outer catching limb (7b) of said catching ring means (7).

16. A suspension strut as set forth in one of claims 1 - 15, said catching ring means (7,107) being laid upon the respective spring carrier member (8,8a) and held in position by the helical compression spring (2).

17. A suspension strut as set forth in one of claims 1- 16, said catching ring means (7) being allocated to said container-side spring carrier member (8).

18. A suspension strut as set forth in one of claims 1 - 16, said catching ring means (107) being allocated to said body-work-side spring carrier member (8a).

19. A suspension strut as set forth in one of claims 1 - 16, said catching ring means (7,107) being allocated to both said container-side spring carrier member (8) and said body-work-side spring carrier member (8a).

20. A suspension strut for a vehicle comprising an oscillation damper (1, 10), said oscillation damper (1,10) having an axis, a container (1), a piston rod (10) axially movable with respect to said container (1) and a container-side spring carrier member (8) axially fixed to said container (1), said container (1) being connectable to a portion (12) of respective wheel supporting means and said piston rod (10) being connectable with a portion (14) of a respective vehicle body work, said suspension strut further comprising a helical compression spring (2) having an axis and being supportable 1 Q 1 1 4 by one (2a) of its ends (2a,2b) on said container-side spring carrier member (8) and supportable by the other (2b) of its ends (2a,2b) on a body-work-side spring carrier member (8a) substantially stationary with respect to said body work, said helical compression spring (2) being accommodated by at least one end (2a,2b) thereof within spring catching means (7,107) allocated to the respective one of said spring carrier members (8,8a), characterized by said spring catching means (7,107) comprising catching ring means (7,107) produced separately from and carried by the respective spring carrier member (8,8a), said catching ring means (7,107) comprising an annular catching member (4,5) radially centered with respect to the respective spring carrier member (8,8a).

21. A suspension strut substantially described by way of example with reference to Figure 1 of the accompanying drawings.

Published 1993 at The Patent Office. Concept House. Cardiff Road. Newport. Gwent NP9 1 RH. Further copies may. be obtained Sales Branch. Unit 6. Nine Mile Point. CIAmfelinfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques ltd. St Mary Cray. Kent.