IMPROVED VEHICLE WHEEL BEARING

Abstract: A taper roller bearing for a non-driven wheel of a vehicle has the annular cup member 10, which provides its outer raceway 11, formed with an axial extension 17 over which the rim member of the wheel can be slipped to support and locate the rim while it is being engaged on the wheel studs and while the wheel nuts are placed in position. The extension 17 has its outer end part 19 which is to receive the rim formed slightly smaller external diameter than the main part of the cup. The cone member of the bearing, which provides the inner raceway, may have an axial extension projecting in the opposite direction to the extension of the cup to form a spacer between the bearing and second taper roller bearing disposed coaxially with or in the opposite sense to the first bearing.

Description: This invention relates to thrust bearings for vehicle wheels, primarily non-driven wheels. EP-A-0 098 817 shows and discloses a typical thrust bearing arrangement for a vehicle wheel, the outer race rings being totally enclosed in a hub element over which the wheel is passed for securing to the hub element in the conventional manner. According to the invention in one aspect there is provided a thrust bearing comprising an outer race ring 10 having a thrust raceway 13 on its radially outer face, rolling thrust elements 14 mounted radially between and in rolling contact with said raceways, characterized in that said outer race ring 10 has an axial extension portion 19 adapted to operate as a centring support for a vehicle wheel rim. The outside diameter of said extension portion is such as to allow an easy sliding fit for the wheel rim and for this purpose the extension portion may have a lesser diameter than the main portion of the outer race ring. The free end of the extension portion may have a chamfered external diameter for facilitating location of the wheel rim on the extension portion. The extended portion will be of a length such as to protrude beyond the hub assembly of the vehicle wheel, when fitted, by an amount sufficient to enable the central aperture in the wheel rim and in certain circumstances in a brake disc or brake drum to which the wheel rim is to be bolted to be located over it. The extension portion is preferably a little longer than this in practice to give some leeway for small movement of the wheel during fitting and initial tightening of the wheel nuts, to ensure that the wheel is supported during these operations. In one embodiment, the inner race ring is likewise extended axially, but in the opposite direction, to act as a spacer for spacing the bearing from a second bearing coaxial with the first bearing and used in conjunction with the first bearing in a twin bearing arrangement. This second bearing, being positioned inwardly of the first bearing, may have an extended inner race ring, if desired, to increase the spacing between the raceways of the two bearings. The invention also provides a double thrust bearing arrangement for a vehicle wheel, comprising a stub axle 24, two thrust bearings each including an outer race ring 10, an inner race ring 12, said inner and outer race rings respectively having radially outer and radially inner surfaces formed with bearing thrust raceways, rolling thrust elements 14 mounted radially between and in rolling engagement with said raceways, said bearings being disposed in opposition to each other and having their inner race rings 12 secured on said stub axle characterized in that the outer race ring of the bearing nearer the free end of the stub shaft has an axial extension portion 19 projecting in a direction away from the other bearing and adapted to operate as a centring support for a vehicle wheel rim. In order that the invention may be better understood, an embodiment thereof will now be described by way of example only, with reference to the accompanying diagrammatic drawings in which:- Figure 1 is a side sectional view of a tapered roller thrust bearing according to the invention; and Figure 2 shows the use of the bearing of Figure 1 in a twin thrust bearing arrangement for the wheel hub of a motor vehicle. Referring to Figure 1 of the drawings, the thrust bearing comprises a cylindrical outer race ring 10 having an outer thrust raceway 11 and a cylindrical inner race ring 12 having an inner thrust raceway 13. Mounted between the inner and outer raceways are a plurality of tapered rolling thrust elements 14 circumferentially spaced apart by a cage 15. An annular seal 16 seals the gap between the race rings 10 and 12 to prevent ingress of moisture and dirt from the exterior of the bearing. Extending axially from that end of the outer race ring 10 having the largest internal diameter is a cylindrical extension portion 17 whose outer end is chamfered at 18. The outer end portion 19 is of reduced diameter suitable to allow location thereon of a wheel rim 20 (see Figure 2). The diameter of the main portion of outer race ring 10 is such as to provide a tight fit in a suitable aperture in the wheel hub; the diameter of portion 19 is such as to allow an easy sliding fit for the wheel rim. The inner race ring 12 has an axial extension portion 21 extending in the opposite direction to portion 17. Extension portion 21 is intended to space the bearing from an adjacent bearing in multi-bearing arrangement, for example as shown in Figure 2, to which attention is now directed. Figure 2 shows a two bearing arrangement for use in a motor vehicle wheel bearing assembly. The assembly comprises two tapered roller thrust bearings 22, 23 mounted in opposite senses on a stub axle 24. The stub axle 24 is provided with an abutment 25 for the left hand (outer) bearing 12. The outer bearing 22 is of the type described above with reference to Figure 1; the right hand (inner) bearing 23 is of similar construction, but does not possess the extended rim location portion 17. Both bearings have extended spacer portions 21, the tips of which abut one another to give the required inter-bearing spacing. The inner race rings of both bearings are mounted in the wheel hub, shown under reference 26. Attached to the front surface of the wheel hub is a brake member 27. Both the the wheel hub and brake member have a ring of apertures 28 centred on the axis of the stub axle 14 for receiving fixing bolts (not shown). The wheel rim 20 is the outermost element in the illustrated assembly and is readily fitted by locating it on the cylindrical boss formed by the protrusion of the extension portion 17 beyond the brake member 27. The wheel is thus readily located in position and is supported during the fitting and initial tightening of the wheel bolts. In practice the illustrated bearing will be pregreased so that the wheel manufacturer does not need to carry out this process. The use of high capacity tapered roller thrust bearing of minimum outside diameter, with integrated seal, pre- adjusted and having an extended outer race ring such as described above, offers the following advantages in a non-driven wheel for an automobile or light truck:- simple hub shape less machining surfaces more space for brake components reduced hub outside diameter permits the use of lower strength, lower cost material for the hub.

Claims: A thrust bearing comprising an outer race ring (10) having a thrust raceway (11) its radially inner face, an inner race ring (12) having a thrust raceway (13) on its radially outer face, rolling thrust elements (14) mounted radially between and in rolling contact with said raceways, characterized in that said outer race ring (10) has an axial extension portion (19) adapted to operate as a centring support for a vehicle wheel rim. A thrust bearing as claimed in claim 1, characterized in that said extension portion (19) has a lesser external diameter than the main portion of the outer race ring (10). A thrust bearing as claimed in claim 1 or claim 2, characterized in that the free end of the extension portion (19) has a chamfered external diameter for facilitating location of the wheel rim on the extension portion. A thrust bearing as claimed in any one of the preceding claims, characterized in that the inner race ring (12) has an axial extension portion (21) projecting in the opposite direction to the extension portion (19) of the outer race ring. A double thrust bearing arrangement for a vehicle wheel, comprising a stub axle (24), two thrust bearings each including an outer race ring (10), an inner race ring (12), said inner and outer race rings respectively having radially outer and radially inner surfaces formed with bearing thrust raceways, rolling thrust elements (14) mounted radially between and in rolling engagement with said raceways, said bearings being disposed in opposition to each other and having their inner race rings (12) secured on said stub axle characterized in that the outer race ring of the bearing nearer the free end of the stub shaft has an axial extension portion (19) projecting in a direction away from the other bearing and adapted to operate as a centring support for a vehicle wheel rim. A double thrust bearing arrangement as claimed in claim 5 characterized in that the inner race rings (12) of said bearings have axial extension portions (21) projecting into abutment with each other.

Inventors: CANDIARD, RENE, Candiard, René
Applicants: THE TIMKEN COMPANY
Application year: 1988
Main classification: B60B27
IPC codes: B60B27, F16C19, F16C33, B60B35