Taper Roller Bearings for Vehicle Wheels

This invention relates to taper roller bearings for vehicle wheels, primarily non-driven wheels.

According to the invention in one aspect there is provided a tapered roller bearing comprising a bearing cone, a bearing cup encircling the bearing cone, said cone and said cup respectively having radially outer and radially inner faces formed with bearing raceways, tapered rollers mounted radially between the cone and the cup and in rolling engagement with said raceways, said bearing cup having an axial extension portion 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 bearing cup. The free end of the extension portion may have an external chamfer 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, 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. 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 bearing cone 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 bearing cone, if desired, to increase the spacing between the raceways of the two bearings.

The invention also provides a tapered roller bearing arrangement for a vehicle wheel, comprising a stub axle, two tapered roller bearings each including a bearing cone, a bearing cup encircling the bearing cone, said cone and said cup respectively having radially outer and radially inner surfaces formed with bearing raceways, tapered rollers mounted radially between and in rolling engagement with said raceways, said bearings having their bearing cones secured on said stub axle with the smaller diameter ends of their respective raceways adjacent each other, the bearing cup of the bearing nearer the free end of the stub shaft having an axial extension portion projecting in a direction away from the other bearing and adapted to operate as a centring spigot 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:

FIG. 1 is a side sectional view of a tapered roller bearing according to the invention; and

FIG. 2 shows the use of the bearing of FIG. 1 in a twin bearing arrangement for the wheel hub of a motor vehicle.

Referring to FIG. 1 of the drawings, the bearing comprises a cylindrical cup 10 having an outer raceway 11 and a cylindrical cone 12 having an inner raceway 13. Mounted between the inner and outer raceways are a plurality of tapered rollers 14 circumferentially spaced apart by a cage 15. An annular seal 16 seals the gap between the cup and the cone to prevent ingress of moisture and dirt from the exterior of the bearing.

Extending axially from that end of the cup 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 cup 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 cone 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 FIG. 2 to which attention is now directed. FIG. 2 shows a two bearing arrangement for use in a motor vehicle wheel bearing assembly. The assembly comprises two tapered roller 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 FIG. 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 cone spacer portions 21, the tips of which abut one another to give the required inter-bearing spacing.

The cups 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 taper roller bearing of minimum outside diameter, with integrated seal, preadjusted and having an extended cup (outer) member 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.