GB2050968A

GB2050968A - Strut for suspensions for motor vehicles

Info

Publication number: GB2050968A
Application number: GB8016174A
Authority: GB
Original assignee: IAO Industrie Riunite SpA
Current assignee: IAO Industrie Riunite SpA
Priority date: 1979-05-28
Filing date: 1980-05-15
Publication date: 1981-01-14
Also published as: FR2457780A1; IT7968142A0; ES250978U; ES250976U; FR2457780B1; DE3017737A1; ES250977U; GB2050968B; IT1118742B

Abstract

A strut comprises a metal tubular member (10) forming the cylinder of a telescopic shock absorber and a bracket (32) of sheet metal welded to tubular member (10) having a U-sectioned portion with a yoke (34) which embraces a lower part of the tubular member and a pair of parallel cheeks (36) to which a wheel-bearing member (14) is attached by bolts (30). The bracket (32) has a C-sectioned upper portion (40) which at least partially surrounds the tubular member (10) and which supports a steering or anchoring arm (50). Torsional and flexural stresses between the wheel-bearing member (14) and the arm (50) pass through the bracket (32) rather than the lower part of the tubular member (10). <IMAGE>

Description

SPECIFICATION Strut for suspensions for motor vehicles This invention relates to a strut for suspensions for motor vehicles, comprising a metal tubular member which forms the cylinder of a telescopic shock absober, and a sheet metal bracket welded to the tubular member and having a U-sectioned portion with a yoke which embraces a lower part of the tubular member and with a pair of cheeks substantially parallel to each other, projecting laterally with respect to the tubular member and adapted for the attachment of a wheel-bearing member.

Struts of this type comprising a steering or anchoring arm are already known. This arm is secured to a bracket stirrup which is different from the one referred to above and which is welded independently to the tubular member above the attachment bracket of the wheel-bearer member. In struts associated with the steering wheels, the arm is connected to a steering rod by an articulated joint. In certain struts associated with non-steering wheels, a similar arm is connected to an anchoring bar on the bodywork.

In both cases the torsional stresses transmitted between the wheel-bearing member and the arm pass through that part of the tubular member which is between the two brackets.

A metal tubular member with a "sound" structure is able to withstand the torsional stresses without difficulty. However, the welds connecting the two brackets to the tubular member constitute areas of weakness. On one hand, the welds themselves are susceptible to failure, on the other hand, the welds degrade the structure of the particular metal tubular member in the zone in which it is most stressed, and make it susceptible to failure through the effect of the stresses resulting from the torsional and flexural forces.

The problem from which the present invention stems is that of providing a strut of the type referred to at the beginning, in which the tubular member is little stressed precisely in the zone in which the stresses of torsion and of bending are transmitted from the wheel-bearing member to the steering or anchoring arm.

According to the present invention there is provided a strut for suspensions for motor vehicles, comprising a metal tubular member which forms the cylinder of a telescopic shock absorber, and a bracket of sheet metal welded to the tubular member and having a U-sectioned portion with a yoke which embraces a lower part of the tubular member and with a pair of cheeks, substantially parallel to each other, projecting laterally with respect to the tubular member and adapted for the attachment of a wheel-bearing member, wherein the bracket has a C-sectioned upper extension which at least partially surrounds the tubular member and which is adapted to support a steering or anchoring arm or attachment means for such an arm.

By this solution, the torsional and flexural stresses are transmitted directly, through the bracket, from the steering or anchoring arm to the wheel-bearing member and vice versa, as a result of which the tubular member is not involved in the transmission of these stresses.

Embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figures 1 and 2 are two perspective views of a strut according to a first embodiment of the invention.

Figure 3 is an 'exploded' perspective view of the strut of Figures 1 and 2.

Figure 4 is a side view, partially sectioned in the vertical plane indicated by the line IV-IV of Figure 1, and in which are shown in broken out lines some members associated with the strut, Figure 5 is a transverse section, on an enlarged scale, taken along the line V-V of Figure 4, Figure 6 is a perspective view of a strut according to a second embodiment of the invention, Figure 7 is an 'exploded' perspective view of the strut of Figure 6, Figure 8 is a partially-sectioned, elevational view, Figure 9 is a section, on an enlarged scale, of the parts contained within the circles indicated by IX in Figure 8, Figure 70 is a section, on an enlarged scale, taken along the line X-X of Figure 8, Figure ii is a fragmentary perspective view of a strut according to a third embodiment of the invention, Figure 12 is a perspective view, on an enlarged scale, of a connecting member for a steering or anchoring arm of the strut of Figure 11, and Figure 13 is a fragmentary longitudinal section of the strut, taken on an enlarged scale in the plane indicated by the line XIII-XIII of Figure 11.

Referring to Figures 1 to 4, a strut of a MacPhereson-type suspension for a front steering wheel of a motor vehicle comprises a sheet metal tubular member 10 which forms the cylinder of a telescopic hydraulic shock absorber. Only the lower part of this tubular member 10 has been shown.

The strut shown is intended for a suspension comprising a helical spring M (Figure 4). A small sheet metal plate 12 is welded to the tubular member 10 and is adapted to form a shoulder or abutment member for the lower end of the spring M.

In the case of suspensions of a different type, for example with a torsion bar, leafspring etc., the small plate 12 is absent.

To the lower part of the tubular member 10 is secured, in the manner which will be clarified below, a wheel-bearing member 14. In the example shown, the member 14 comprises a piece of forged steel our a casting of steel or cast iron. However, this does not exclude the use of a wheel-bearing member comprising a piece of strong, drawn sheet metal in the form of housing.

The member 14 has, among other things, a bush portion 16 which has a cylindrical seat 18 adapted to receive a bearing bush, indicated diagrammatically by BP in Figure 4. The bush portion 16 has lateral lugs 20 which serve to secure the stator part of a wheel brake (the gripper-holder of a disc brake, or the shoe-holder plate of a drum-brake).

The member 14 includes, in addition, a lower arm 22 which has a conical hole 24 and serves to secure a part (spherical pin or seat) of a ball and socket joint GN for the articulation of one end of a suspension wishbone BO (Figure 4).

The member includes an upper connecting part 26 defined by two flat lateral faces, and which has a pair of holes 28 for the passage of bolts 30.

Associated with the tubular member 10 there is a bracket, generally indicated 32, which is formed by a shaped piece of strong, pressed sheet metal.

A lower part of the bracket 32 is U-sectioned and comprises a substantially semi-cylindrical yoke 34 which embraces the lower part of the tubular member 10. The yoke 34 is extended by a pair of cheeks 36 which are substantially parallel to each other, and project laterally with respect to the tubular member 10.

The connecting member 26 of the wheel-bearing member 14 is inserted between the two cheeks 36, which have corresponding pairs of holes 38 for the passage of the bolts 30.

The bracket 32 comprises an upper extension 40.

This extension is C-shaped in section and envelops (surrounds) the tubular member 10 by more than 1800. The upper part af the extension 40 is longitudinaily divided by a rear notch 42 which is substantially U-shaped and opens upwardly. This notch defines a pair of opposing portions, which are bent towards the exterior from opposing sides of the tubular member 10 and from respective lugs 44. The lugs 44 have respective holes 46 for the passage of bolts 48.

With reference to Figure 5, as well as Figures 1 to 4, the two lugs 44 lie in a common plane which is parallel to the axis of the tubular member 10 and substantially perpendicular to the substantially parallel common planes of the cheeks 36.

On the side of the strut 10 opposite the side where the wheel-bearing member 14 is located there is situated a steering arm (or anchoring arm), generally indicated 50. The arm 50, which may comprise a piece of forged steel, or a piece of pressed sheet metal, has at an "internal" end, a portion 52 which is shaped like a bearing cap and has a pair of holes 54 corresponding to the holes 46 of the lugs 44. At the opposite or "external" end of the arm 50 has an eye 56 adapted to receive a part of a universal joint for connection to a steering linkage orto an anchoring bar.

The bolts 48 permit the securing of the arm 50 to the lugs 44.

In correspondence with the notch 42, the upper extension 40 of the brackets 32 defines a pair of curved wing pieces 58 which embrace the tubular member 10 on its opposite side with respect to the yoke 34. As may be clearly seen in Figure 5, the wingpieces 58 together with th cap-shaped portion 52 of the arm 50, closely encompass the tubular member 10 over the greater part of its circumfer ence.

The bracket 32 is welded to the tubular member in three distinct zones. A first zone is situated at the height of the cheeks 36 and a second zone is situated at the height of the upper extension 40. A third zone is situated at the lower end of the tubular member 10.

In the first zone, the yoke 34 has a rear eyelet 60, extending longitudinally. At least the longitudinal sections of the peripheral edge of the eyelet 60 are connected to the tubular member 10 by means of bead welds 61.

In the second welding zone, the bracket 32 is secured to the tubular member 10 by means of a pair of bead welds 62 (Figure 5) which extend along the free edges of the wingpieces 58.

In the third welding zone, the lower edge of the bracket 32 is connected to the lower end of the tubular member 10 by means of a peripheral bead weld 63 (Figure 2).

The second embodiment of the invention, shown in Figures 6 to 10, will now be described. In Figure 6 to 10 the parts identical to those in Figures 1 to 5 have been given the same reference numerals and will not be described below, whilst the analogous parts will be indicated by the same reference numerals increased by 100.

In the second embodiment bracket 132 comprises a U-shaped lower part exactly the same as that of the bracket 32.

The bracket 132 comprises a pair of opposing cheeks 136 for the attachment of the connecting part 26 of the wheel-bearing member 14. In the yoke 134 of the bracket 132 there is made, at the height of the cheeks 136, an eyelet 160 analogous to the eyelet 60 and having at least its longitudinal edges connected to the lower part of the tubular member 10 by means of bead welds, indicated by 161 in Figure 8. A peripheral bead weld 163 connects the lower edge of the bracket 132 to the lower end of the tubular member 10 (Figure 8).

The bracket 132 differs from the bracket 32 in that its upper extension 140 is a greatly closed C-shape, that is, it is in the form of a sectioned tube, with a longitudinal split 141 which extends along a diametrical plane of symmetry relative to the two cheeks 136.

In the second embodiment the steering or anchoring arm 150 comprises a pair of strong sheet metal members 150a and 150b, welded together in such a manner as to give the arm a flat, box-shaped structure with two substantially parallel, spacedapart principal walls. The arm 150 has a connecting eye defined by a pair of aligned and flanged circular apertures 152a,152b. The arm 150 also has a further eye 156, adapted to receive a part of a universal joint for connection to a steering linkage or an anchoring bar.

The upper extension 140 of the bracket 132 and the strut 10 are inserted into the two apertures 1 S2a, 152b defining the connecting eye. The dimensions are such that the upper extension 140 is maintained firmly locked around the tubular member 10. This arrangement makes it possible to achieve a perfect concentricity between the connecting eye 152a, 152b of the arm 150 and the axis of the tubular member 10.

The arm 150 is secured to the upper extension 140 of the bracket 132 by means of bead welds 154a, 154b which interconnect the extension and the edges of the circular apertures 1 52a, 1 52b, as illustrated in Figure 9.

The upper end of the extension 140 projects with respect to the upper edge of the aperture 1 52a and its terminal edge is secured to the tubular member 10 by means of a peripheral bead weld 162, which is clearly visible in Figure 9.

Finally, there follows a description of the embodiment shown in Figures 11 to 13. In this embodiment the wheel-bearing member has not been represented, since it is assumed to be identical to that of the preceding embodiments. The bracket associated with the tubular member 10 is identical to that of the second embodiment and is again generally indicated 132. Its upper extension 140 again is in the form of a longitudinally sectioned tube with a split 141 extending along the diametrical plane of symmetry of the two cheeks 136.

In the third embodiment the steering or anchoring arm is similar or identical to that of the first embodiment and is again indicated by 50.

In order to secure the arm 50 to the strut there is provided a connecting member of strong sheet metal, generally indicated 200 and more clearly visible in Figure 12. The connecting member 200 comprises two C-shaped pieces of sheet metal 202 and 204. The cores of these two pieces 202, 204 are welded back to back so as to form a pair of double-walled lug elements 244, having the same function as the lugs 44 of the first embodiment. The two lug elements 244 have respective holes 246 for the passage of the bolts 48 for securing the bearing cap-shaped portion of the arm 50.

The two lug elements 244 interconnect a pair of upper and lower walls, 250a and 250b respectively, each of which is defined by corresponding wingpieces of the two C-members 202, 204.

The two walls 250a, 250b are parallel with each other and each of them has a respective circular aperture 2S2a, 252b. The two lug elements 244 are situated in opposing positions and in a chordal plane with respect to the apertures 252a,252b.

The upper extension 140 of the bracket 132 and the strut 10 are inserted, in a manner wholly analogous to that of the second embodiment, into the two apertures 2S2a, 252b of the connecting member 200, as a result of which the latter maintains the upper extension 140 firmly locked around the tubular member 10, with the same advantage of coaxiality discussed with reference to the second embodiment.

The connecting member 200 is secured to the upper extension 140 by means of bead welds 254a, 254b entirely analogous to the beads 1 54a, 154b of the second embodiment. These beads 254a, 254b interconnect the extension 140 and the edges of the circular apertures 252a,25Zb.

The upper terminal edge of the extension 140 projects above the upper wall 250a of the connecting member 200 and, as in the second embodiment, is secured to the tubular member 10 by means of a peripheral bead weld 162.

Another bead weld (not shown), analogous to the beads 63 and 163 of the preceding embodiments, interconnects the lower edge of the bracket 132 and the lower end of the tubular member 10.

In all forms of embodiment described and illustrated, it will be understood that the torsional and flexurai stresses transmitted from the arm 50 or 150 to the wheel-bearing member 14 and vice versa do not pass through the lower part of the tubular member 10, but through the bracket 32 or 132 alone.

In all three forms of embodiment the bead welds, by means of which the bracket 32 or 132 is secured to the tubular member 10, are not positively affected by the torsional stresses.

Claims

1. A strut for suspensions for motor vehicles, comprising a metal tubular member which forms the cylinder of a telescopic shock absorber, and a bracket of sheet metal welded to the tubular member and having a U-sectioned portion with a yoke which embraces a lower part of the tubular member and with a pair of cheeks, substantially parallel to each other, projecting laterally with respect to the tubular member and adapted for the attachment of a wheel-bearing member, wherein the bracket has a C-sectioned upper extension which at least partially surrounds the tubular member and which is adapted to support a steering or anchoring arm or attachment means for such an arm.

2. A strut as claimed in claim 1, wherein the C-sectioned upper extension surrounds the tubular member by more than 1800.

3. A strut as claimed in claim 1 or claim 2, wherein the upper extension of the bracket supports a pair of opposing lateral lugs, lying in a common plane parallel to the axis of the tubular member, said lugs being adapted for the attachment, by means of bolts, of respective lateral lugs of a connecting part, formed like a bearing cap, of the steering or anchoring arm.

4. A strut as claimed in claim 3, wherein the upper extension of the bracket is longitudinally divided, in correspondence with the yoke, by a notch having a substantially U-shaped section and opening upwardly, and which defines a pair of opposing portions, which are bent towards the exterior from opposite sides of the tubular member to form the lugs, the lugs lying in a common plane substantially perpendicular to the common planes of the cheeks.

5. A strut as claimed in claim 4, wherein the C-sectioned upper extension has opposing longitudinal edges which are connected to the tubular member by means of respective bead welds.

6. A strut as claimed in claim 3, and including a connecting member of sheet metal comprising a pair of spaced-apart parallel walls having respective aligned circular apertures and interconnected by a pair of lug elements situated in opposing positions in a chordal plane with respect to the apertures, the upper extension of the bracket being in the form of a longitudinally sectioned tube, the upper extension and the tubular member being inserted into the two apertures of the connecting member, which maintains the upper extension in concentric locking around the tubular member, the connecting member being secured to the upper extension by means of bead welds which interconnect the extension and the edges of the circular apertures, and the lug elements having respective holes and forming the lugs for securing of the steering or anchoring arm.

7. A strut as claimed in claim 6, wherein the connecting member comprises two pieces of Cshaped sheet metal the cores of which are welded back to back to form the lug elements and the wingpieces of which form conjointly, in pairs, the parallel walls.

8. A strut as claimed in claim 2, and including a steering or anchoring arm comprising a pair of sheet metal members welded together so as to give the arm a flat box-shaped structure with two substantially parallel, spaced apart principal walls, wherein the arm has a connecting eye defined by a pair of aligned circular apertures made in the principal walls, wherein the upper extension of the bracket is in the form of a longitudinally sectioned tube, and wherein the upper extension and the tubular member are inserted into the two circular apertires defining the connecting eye of the arm in such a manner as to maintain the upper extension concentrically locked around the tubular member, and wherein the arm is secured to the upper extension by means of bead welds which interconnect the extension and the edges of the circular apertures.

9. A strut as claimed in claim 6 or claim 8, wherein the upper extension of the bracket is secured to the tubular member by means of a peripheral bead weld which interconnects the tubular member and an upper terminal edge of the extension.

10. A strut as claimed in any one of the preceding claims, wherein the yoke of the bracket has a rear eyelet, aligned longitudinally and situated at the height of the cheeks, and wherein the yoke is secured to the tubular member by means of bead welds which extend at least along the longitudinal parts of the peripheral edge of the eyelet.

11. A strut as claimed in claim 6 or claim 8, wherein the tubular sectioned upper extension of the bracket has a longitudinal split which extends along a diametrical plane of symmetry of the two cheeks of the bracket.

12. A strut for suspensions for motor vehicles substantially as herein described with reference to and as illustrated in Figures 1 to 4, Figure 5 to 10, or Figures 11 to 13, of the accompanying drawings.

13. A motor vehicle suspension including a strut as claimed in any one of the preceding claims.

14. A motor vehicle including a strut as claimed in any one of claims 1 to 12.