GB1586057A

GB1586057A - Resilient mountings

Info

Publication number: GB1586057A
Application number: GB27956/76A
Authority: GB
Original assignee: Dunlop Ltd
Current assignee: Dunlop Ltd
Priority date: 1976-07-03
Filing date: 1976-07-03
Publication date: 1981-03-18
Also published as: BE856400A; DE2730184A1; DE2730184C2

Description

(54) IMPROVEMENTS IN AND RELATING TO RESILIENT MOUNTINGS (71) We, DUNLOP LIMITED, an English Company of Dunlop House, Ryder Street, St. James's London S.W.l do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to resilient mountings and in particular to a mounting in the form of a resilient torsion bearing component and assembly thereof.

One common application of a resilient torsion bearing component is resiliently to interconnect a vehicle body and anti-roll bar to allow relative torsional movement therebetween. Torsion bearings for this application often comprise an annular rubber element surrounding the anti-roll bar and held in compression against the anti-roll bar by an outer metal ring to which the rubber element is bonded.

For convenience of assembly around an antiroll bar it is normal for the outer metal ring and annular rubber element to be formed by a pair of similar semi-cylindrical components so that the rubber material is compressed as the outer metal ring halves of the two components are brought together to form a continuous ring. In this form of construction relative torsional movement between the antiroll bar and metal ring is accommodated by torsional shear in the rubber element, with the rubber element being held against slipping relative to the surface of the anti-roll bar by frictional forces resulting from compression of the rubber material.

A disadvantage of this construction, however, is that if a high torsional stress is imposed on the bearing the rubber element slips relative to the surface of the anti-roll bar and, since the anti-roll bar typically has a relatively rough surface as results from being fabricated by a forging process, there results a considerable wear on the rubber element during slipping. The wear problem could be overcome by bonding the rubber element to the anti-roll bar or by machining the anti-roll bar surface but these solutions have the disadvantage respectively of being more difficult to assemble and time-consuming in manufacture.

It has been proposed to improve the ability of a torsional bearing to withstand a high torsional stress without slipping between the rubber element and surface of an anti-roll bar by increasing the radial thickness of the rubber element so as to improve its ability to accommodate torsional shear. The drawback of this solution is, however, that the radial stiffness of the bearing is substantially reduced.

According to the present invention there is provided a resilient torsion bearing assembly comprising: an inner rigid member, a first element of resilient elastomeric material extending around the inner rigid member, a second element of plastics material bonded to and extending around the resilient first element, and an outer rigid member extending around the second element and having a bearing surface to permit relative slipping movement between said member and the second element, said elastomeric material of the resilient first element being subject to compression between the second element and the inner rigid member whereby the compression force at the interface of the first element and the inner rigid member restrains slipping movement therebetween such that increasing relative torsional movement between the rigid members initially causes torsional stress in the elastomeric material and then slipping movement between the outer rigid member and the second element.

The resilient torsion bearing assembly may be segmental, a complete bearing unit being formed from an assembly of several segmental components. In this case the segmental components may be provided with flanges for the securing together of successive components.

The outer rigid member may be of plastics or metal.

The second element and resilient first element may be bonded together by the use of adhesives, or the two elements may be united together by a fusion bonding method such as, for example, that described in the specifications of our U.K. Patents 1408558 and 1408557. Alternatively, the first and second elements may be united by a friction welding method such as that described in the specification of our co-pending U.K. Patent No. 1456855.

To permit slipping movement between the second element and outer rigid member the bearing surface of the second element should be of substantially circular or arcuate crosssectional shape, and the cross-sectional shape may be of uniform or varying size along the axial length of the bearing to result in a bearing surface which is either of cylindrical or other, for example, frusto-conical shape.

In contrast, the surface of the first element for non-sliding association with the inner rigid member may be such that said surface is other than of circular cross-sectional shape, though a circular cross-sectional shape is acceptable.

One embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings in which: Figure 1 is an end view of a segmental bearing component in accordance with the present invention shown in position relative to an anti-roll bar; Figure 2 is a side view of the component shown in Figure 1, and Figure 3 is a section on the line A-A of Figure 1.

A semi-circular-shaped segmental bearing component 10 for resiliently mounting an anti-roll bar to a vehicle body comprises a semi-cylindrical first element 11 of natural rubber located within and fusion-bonded to a semi-cylindrical second element 12 formed from Nylon 6 material. The nylon element 12 is formed at its axial ends with radially outwardly projecting shoulders 13 so as to define in cross-section as shown in Figure 3 a channelshaped depression having a semi-circular bearing surface 14a and end bearing surfaces 14b. An outer rigid member 15 formed from pressed metal locates in siad channel against the bearing surfaces 14a and 14b, and is provided along its longitudinal edges 16 with radially outwardly extending arms 17 having apertures by means of which a pair of the segmental bearing components may be bonded together around an anti-roll bar 18.

The rubber element 11 is designed, for use in conjunction with an anti-roll bar of given external diameter, to have sufficient thickness to ensure that when two outer metal members are bolted together around an anti-roll bar the rubber becomes sufficiently compressed and exerts sufficient frictional force on the antiroll bar to ensure that slipping does not occur between the rubbers and the roll bar. Furthermore, this compression of the rubber element is selected such that in the assembly sufficient frictional force exists between the metal member and nylon element to prevent relative slipping therebetween until a preselected torsional loading on the bearing is approached.

In operation of the torsional bearing, relative torsional movement between the antiroll bar and a vehicle body to which the rigid metal member 1 5 is secured initially causes torsional stressing of the rubber element 11.

When this stress level beings to approach a level at which slipping might otherwise occur between the rubber and outer metal surface of the anti-roll bar 18 slipping instead occurs between the nylon element and outer metal member in the manner of slipstick movement.

Relative movement between the rubber element and anti-roll bar is thereby prevented and the disadvantage of consequential wear of the rubber element as described above is accordingly avoided. This mode of operation results in the normal small dynamic torsional excursions being accommodated by the rubber element in torsional shear, whilst the more infrequent large torsional movements are accommodated by the nylon bearing.

In a modified construction seals may be provided on the shoulders 13 to prevent or restrict the ingress of dirt to the bearing surfaces 14a and 14b.

To improve the bearing capabilities of the nylon element at its surface 1 4a and 1 4b the nylon may incorporate a lubricant such as graphite powder.

WHAT WE CLAIM IS: 1. A resilient torsion bearing assembly comrising: an inner rigid member, a first element of resilient elastomeric material extending around the inner rigid member, a second element of plastics material bonded to and extending around the resilient first element, and an outer rigid member extending around the second element and having a bearing surface to permit relative slipping movement between said member and the second element, said elastomeric material of the resilient first element being subject to compression between the second element and the inner rigid member whereby the compression force at the interface of the first element and the inner rigid member restrains slipping movement therebetween such that increasing relative torsional movement between the rigid members initially causes torsional stress in the elastomeric material and then slipping movement between the outer rigid member and the second element.

2. A resilient torsion bearing assembly according to Claim 1 wherein the assembly is a segment for a substantially annular bearing.

3. A resilient torsion bearing assembly according to Claim 1 or Claim 2 wherein the bearing surface of the second element is of substantially circular or arcuate cross-sectional shape.

4. A resilient torsion bearing assembly according to Claim 3 wherein said cross-sectional shaped is of a varying size along the axial

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. second elements may be united by a friction welding method such as that described in the specification of our co-pending U.K. Patent No. 1456855. To permit slipping movement between the second element and outer rigid member the bearing surface of the second element should be of substantially circular or arcuate crosssectional shape, and the cross-sectional shape may be of uniform or varying size along the axial length of the bearing to result in a bearing surface which is either of cylindrical or other, for example, frusto-conical shape. In contrast, the surface of the first element for non-sliding association with the inner rigid member may be such that said surface is other than of circular cross-sectional shape, though a circular cross-sectional shape is acceptable. One embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings in which: Figure 1 is an end view of a segmental bearing component in accordance with the present invention shown in position relative to an anti-roll bar; Figure 2 is a side view of the component shown in Figure 1, and Figure 3 is a section on the line A-A of Figure 1. A semi-circular-shaped segmental bearing component 10 for resiliently mounting an anti-roll bar to a vehicle body comprises a semi-cylindrical first element 11 of natural rubber located within and fusion-bonded to a semi-cylindrical second element 12 formed from Nylon 6 material. The nylon element 12 is formed at its axial ends with radially outwardly projecting shoulders 13 so as to define in cross-section as shown in Figure 3 a channelshaped depression having a semi-circular bearing surface 14a and end bearing surfaces 14b. An outer rigid member 15 formed from pressed metal locates in siad channel against the bearing surfaces 14a and 14b, and is provided along its longitudinal edges 16 with radially outwardly extending arms 17 having apertures by means of which a pair of the segmental bearing components may be bonded together around an anti-roll bar 18. The rubber element 11 is designed, for use in conjunction with an anti-roll bar of given external diameter, to have sufficient thickness to ensure that when two outer metal members are bolted together around an anti-roll bar the rubber becomes sufficiently compressed and exerts sufficient frictional force on the antiroll bar to ensure that slipping does not occur between the rubbers and the roll bar. Furthermore, this compression of the rubber element is selected such that in the assembly sufficient frictional force exists between the metal member and nylon element to prevent relative slipping therebetween until a preselected torsional loading on the bearing is approached. In operation of the torsional bearing, relative torsional movement between the antiroll bar and a vehicle body to which the rigid metal member 1 5 is secured initially causes torsional stressing of the rubber element 11. When this stress level beings to approach a level at which slipping might otherwise occur between the rubber and outer metal surface of the anti-roll bar 18 slipping instead occurs between the nylon element and outer metal member in the manner of slipstick movement. Relative movement between the rubber element and anti-roll bar is thereby prevented and the disadvantage of consequential wear of the rubber element as described above is accordingly avoided. This mode of operation results in the normal small dynamic torsional excursions being accommodated by the rubber element in torsional shear, whilst the more infrequent large torsional movements are accommodated by the nylon bearing. In a modified construction seals may be provided on the shoulders 13 to prevent or restrict the ingress of dirt to the bearing surfaces 14a and 14b. To improve the bearing capabilities of the nylon element at its surface 1 4a and 1 4b the nylon may incorporate a lubricant such as graphite powder. WHAT WE CLAIM IS:

1. A resilient torsion bearing assembly comrising: an inner rigid member, a first element of resilient elastomeric material extending around the inner rigid member, a second element of plastics material bonded to and extending around the resilient first element, and an outer rigid member extending around the second element and having a bearing surface to permit relative slipping movement between said member and the second element, said elastomeric material of the resilient first element being subject to compression between the second element and the inner rigid member whereby the compression force at the interface of the first element and the inner rigid member restrains slipping movement therebetween such that increasing relative torsional movement between the rigid members initially causes torsional stress in the elastomeric material and then slipping movement between the outer rigid member and the second element.

length of the bearing.

5. A resilient torsion bearing assembly according to any one of the preceding claims wherein the surface of the inner rigid member for association with the resilient first element is of substantially non-circular or non-arcuate cross-sectional shape.

6. A resilient torsion bearing assembly according to Claim 5 wherein said second element is fusion-bonded to a resilient first element of rubber material.

7. A resilient torsion bearing assembly according to any one of the preceding claims wherein the second element is shaped to restrict or prevent axial movement thereof relative to said outer rigid member.

8. A resilient torsion bearing assembly according to Claim 7 wherein the second element comprises a pair of spaced shoulders which extend radially outwards of the bearing surface of the outer rigid member.

9. A resilient torsion bearing assembly constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

10. An anti-roll bar assembly comprising a bearing assembly according to any one of the preceding claims in which the inner rigid member is an anti-roll bar having an unmachined surface for engagment by the resilient first element.

11. An anti-roll bar assembly constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.