GB2108059A

GB2108059A - Vehicle road wheel

Info

Publication number: GB2108059A
Application number: GB08220948A
Authority: GB
Inventors: Richard Rudolph Woodward; Trevor Edward James Robinson
Original assignee: GKN Kent Alloys Ltd
Current assignee: GKN Kent Alloys Ltd
Priority date: 1981-10-27
Filing date: 1982-07-20
Publication date: 1983-05-11
Also published as: GB2108059B

Abstract

A road wheel comprises a centre (10) and a rim (11), the centre having a peripheral flange (29) which directly engages the radially inner surface (32) of one of the bead seats (20) of the rim so that the external surface (30) of the centre at its outer periphery is substantially flush with the axially outer surface (23) of the bead retaining flange (22) associated with the bead seat (20). The wheel may be made of light metal or alloy, with the rim (11) shrink-fitted and plug or seam welded to the centre (10). The interengaging surfaces (31, 32) of the centre and rim may be conical with a semi-angle of 1 DIVIDED 2-5 DEG . <IMAGE>

Description

SPECIFICATION Road wheels This invention relates to road wheels for receiving pneumatic tyres. The invention is particularly applicable to cast road wheels made of aluminium or a similar light metal or alloy. Often such wheels are "styled". That is to say the centre of the wheel has a design which is considered aesthetically pleasing. Normally such styled wheels are made in one piece by casting. This has the disadvantage that one has to have a complete die set for each wheel capable of producing the rim and the wheel centre simultaneously.

The invention is concerned with so called "aerodynamic" wheels in which the centre fills the whole of the space defined within one of the bead seat portions of the rim, as distinct from joining the rim in the vicinity of the well. If such a wheel is cast in one piece, to enable the casting cores to be removed, the wheel has to be thickened in the region of one of the bead seat portions, as will be described in more detail below, which results in the wheel being unduly heavy and using more material than is necessary.

All wheel rims are made to international standards and it would be convenient to be able to manufacture standard rims and to apply to such rims a styled centre and particularly an aerodynamically styled centre while using the minimum amount of material.

An object of the invention is to enable one easily and economically to manufacture aerodynamically styled wheels in a variety of designs using standard rims.

According to the invention, therefore, we provide a road wheel for a vehicle comprising: (1) a drop centre rim to receive a pneumatic tyre, the rim having a well defined by a base and side walls; bead seat portions providing bead seats to receive the beads of the tyre; and tyre retaining flanges at the axially outer ends of the bead seat portions to retain the beads on the bead seats; and (2) a wheel centre having an external surface visible when the wheel is mounted on a vehicle and a peripheral flange extending transverse to said external surface: the centre being fitted into and secured to the rim so that the radially outer surface of the flange directly engages the radially inner surface of one of said bead seat portions and so that the outer peripheral part of the external surface is substantially flush with the axially outer surface of the adjacent-tyre retaining flange.

The radially inner surface of said one bead seat portion may be provided with a peripheral abutment which is engaged by the free end of the flange.

The rim and the centre may both be made.of metal having the same or similar co-effecients of thermal expansion and said radially inner and outer surfaces may have an interference shrink fit which has been effected by heating the rim, placing the centre in it and allowing the rim to shrink onto the centre.

The radially inner and outer surfaces may be conical surfaces of revolution about the rotary axis of the wheel. The semi-angle of the cone may be between 2 and 50 and is preferably 20.

Preferably the wheel is made of aluminium or a similar light metal or alloy. In such case the centre and rim will preferably be cast. Any form of casting may be used such as low-pressure die casting, gravity die-casting or pore-free die casting in which the mould is filled with a reactive gas before the molten metal is introduced therein.

The flange may be welded to said one bead seat portion with plug or seam welding.

The invention will now be described in detail by way of example with reference to the accompanying drawings in which: FIGURE 1 is a section through a wheel constituting an embodiment of the invention; and FIGURE 2 is a front view of the wheel of Figure 1.

Referring now to the drawings the wheel comprises a centre 10 and a rim 11. The rim is of the drop centre type comprising a well 1 2 defined buy a base 13 and side walls 14 and 15. The wall 15 is joined by a ledge 16 to a bead seat portion 1 7 which has at its axially outer end a tyreretaining flange 1 8. The bead seat portion 1 7 provides a bead seat 1 9 to receive one bead of a pneumatic tyre which is retained on the bead seat 19 by the flange 18.

The well wall 14 connects to a further bead seat portion 20 providing a bead seat 21 for the other bead of the tyre and a tyre-retaining flange 22 to retain the bead on the bead seat 20, the tyre-retaining flange having an axially outer surface 23 generally perpendicular to the rotary axis 24 of the wheel.

The rim may be cast from light alloy or may be formed from an extrusion which is circled and has its ends welded together or may be formed from sheet. The outer surface of the rim will be made to conform to one of the generally accepted International Standards.

The centre 10 will be cast from aluminium or similar alloy and has a central aperture 25 to receive the wheel hub, an inner ring of holes 26 to receive wheel bolts or studs and a further series of decorative and/or ventilation holes 27 outside the holes 26 as shown in Figure 2. The inner surface of the central part of the disc is provided with lightening pockets such as indicated at 28.

The disc has a peripheral flange 29 which extends transversely relative to the external surface 30 of the centre. The flange has a radially outer surface 31 which is conical and which engages a radially inner surface 32 on the bead seat portion 20. The free end 33 of the flange engages an abutment 34 formed on the inner surface of the bead seat portion 20.

It will be noted that the external surface 31 at its radially outer part 35 is substantially flush with the axially outer surface 23 of the flange 22. It will be seen from the drawing that the surfaces are not absolutely flush and that there is a slight step 36 between the parts which helps to hide the joint but the surfaces are nevertheless substantially flush. The drawing shows the surface 30 standing proud of the surface 23. In another embodiment (not shown) the surfaces 23 and 30 may be flush or the surface 23 may stand proud of the surface 30 by a small amount.

It will be noted that the centre fills the whole of the space within the bead seat portion 20 to provide what is known as an aerodynamic wheel since the centre does extend right up to the bead seat portion and tyre-retaining flange instead of being connected to the wheel adjacent the well as shown in chain dotted lines at 37.

If one wished to cast an aerodynamic wheel in one piece then, to enable the central core within the wheel casting to be removed after casting, it would be necessary to thicken up the material under the bead seat portion 20 as indicated by the cross-hatched portion 38 so that the inner periphery 39 of this portion was in line with the inner surface 40 of the well base 13.

This would mean that the wheel would be heavier than necessary by an annulus of material of the section shown at 38 and this would make the wheel more expensive to produce than necessary and also use an unnecessary amount of material. By using the invention, therefore, aerodynamically styled wheels can be produced economically with different centre designs.

The rim and centre can be connected together in any desired fashion. As shown, there is an interference shrink fit between the radially outer surface 31 of the flange 29 and the radially inner surface 32 of the bead seat portion 20. As mentioned these surfaces are conical surfaces of revolution about the rotary axis 24 of the wheel and the semi-cone angle as shown on the drawing is 20 but may be of any value between 1210 and 5". In addition to an interference shrink fit between the two surfaces the centre and the rim may be welded together. This welding may be in the form of plug welds as shown at 41 through the flange 29 but preferably is in the form of a seam weld at the position 42 between the free end 22 of the flange and the abutment 33 on the bead seat portion 20.

It will be seen that the invention provides a construction of aerodynamically styled wheel which is economical in material and which is versatile in that different centres may be used with standard rims.

Claims

1. A road wheel for a vehicle comprising: (1) a drop centre rim to receive a pneumatic tyre, the rim having a well defined by a base and side walls; bead seat portions providing bead seats to receive the beads of the tyre; and tyreretaining flanges at the axially outer ends of the bead seat portions to retain the beads on the bead seats; and (2) a wheel centre having an external surface visible when the wheel is mounted on a vehicle and a peripheral flange extending transverse to said external surface: the centre being fitted into and secured to the rim so that the radially outer surface of the flange directly engages the radially inner surface of one of said bead seat portions and so that the outer peripheral part of the external surface is substantially flush with the axially outer surface of the adjacent-tyre retaining flange.

2. A wheel according to Claim 1 wherein the radially inner surface of said one bead seat portion is provided with a peripheral abutment which is engaged by the free end of the flange.

3. A wheel according to Claim 1 or Claim 2 wherein the rim and the centre are both made of metal having the same or similar co-efficients of thermal expansion and wherein said radially inner and outer surfaces have an interference shrink fit which has been effected by heating the rim, placing the centre in it and allowing the rim to shrink onto the centre,

4. A wheel according to any preceding claim wherein said radially inner and outer surfaces are conical surfaces of revolution about the rotary axis of the wheel.

5. A wheel according to Claim 4 wherein the semi-angle of the conical surfaces is between 2 and 5 .

6. A wheel according to Claim 5 wherein the semi-angle is 20.

7. A wheel according to any preceding claim wherein both the rim and the centre are made of aluminium or a similar light metal or alloy.

8. A wheel according to any one of the preceding claims wherein the rim and the centre are welded together.

9. A wheel according to Claim 8 wherein said flange is weled to said one bead seat portion with plug weids.

10. A wheel according to Claim 8 wherein said flange is welded to said one bead seat portion by a seam weld adjacent to the free end of the flange.

11. A road wheel substantially as hereinbefore described with reference to and as shown in Figures 1 and 2 of the accompanying drawings.