GB2052402A - Wheel - Google Patents

Abstract

A light alloy wheel comprises an extruded alloy rim 10 and a forged or cast alloy centre 11. The rim is formed into a circle and has its free ends welded together and at least one circumferential welded connection 25 is made between the rim and the forged or cast centre. <IMAGE>

Description

SPECIFICATION Wheels This invention relates to wheels and more particularlyto wheels made from light alloy.

Normally light alloy wheels are cast in one piece.

In rare instances, the part of the rim which is cast last is not entirely sound so that, in service, there may be a slow air leak through the rim and the tyre deflates over a numberofdays.

It is an object of the present invention to improve the manufacture of light alloy wheels in the manner described hereinafter.

According to the invention we provide a wheel having: A. A rim consisting of a length of light alloy material which has been extruded with a transverse cross-section of varying thickness and which has then been circled and had its free ends welded together; B. A light alloy centre which has been forged or cast, and C. At least one circumferential welded connection between the rim and the centre.

Since the rim is made from a length of extruded material it has greater integrity than a cast rim so that there is freedom from leakage of the type described above.

The invention allows greater design flexibility because one can have a standard rim and different styled centres which fit the same rim. The wheel can be made lighter than if it is cast in one piece.

Moreover, the wheel can be manufactured at reduced cost.

Preferably, the length of material which forms the rim is extruded with a cross-sectional shape which is substantially that of the finished rim. The rim may be a drop centre rim and the wheel centre may be welded to the rim under the well.

The centre may be formed by conventional casting techniques or by "squeeze" casting in which molten metal is placed in a die and is maintained under pressure during solidification.

The invention will now be described in detail by way of example with reference to the accompanying drawings in which: FIGURE 1 is a partial section through a wheel embodying the invention, and FIGURE 2 is a partial elevation on the nave face of the wheel, i.e. in the direction of the arrow 2 in Figure 1.

The wheel comprises a rim 10 and a centre 11. The rim is formed as a length of extruded light alloy, the rim having a well 12, a first bead seat 13, a ledge 14 between the well and the first bead seat and second bead seat 15. Tyre retaining flanges 16 and 17 are provided at the axially outer ends of the rim section.

It will be noted that the rim has a varying thickness and is particularly strengthened at 18 at the junction between the bead seat 15 and the tyre retaining flange 17. There is also thickened portion 19.

The rim is extruded as a single length and is circled and is then flash butt welded at 20 as shown in Figure 2. Preferably the rim is extruded in its final cross-sectional shape.

The centre 11 is cast or forged as a single piece of light alloy and is provided with a central aperture 21 to receive a hub and a plurality of bolt holes 22. The centre has a number of integral spokes 23 and at its outer periphery has a first flange 24 which fits under the well 12. A circumferential weld 25 connects the rim and the centre. There is also an L-shaped flange 26 which fits within the rim, one limb 27 of the flange 26 engaging the outer surface of one of the well walls and the other limb 28 of the flange engaging underthe bead seat 15. It will be noted that there is a clearance 29 between the L-shaped flange 26 and the rim.

We have found that the wheel can be manufactured more cheaply than a single cast wheel. There is greater flexibility in design because the off-set, the distance indicated by the arrow O in Figure 1 may be changed comparatively easily using the same rim and in some circumstances the same centre. The extruded rim has more integrity than a cast rim because of its method of manufacture.

1. Awheelcomprising: A. a rim consisting of a length of light alloy mat erialwhich has been extruded with a transverse cross-section of varying thickness and which has then been circled and had its free ends welded together; B. a light alloy centre which has been forged or cast; and C. at least one circumferential welded connection between the rim and the centre.

2. A wheel according to claim 1 wherein said length has been extruded with a cross-sectional shape which is substantially that of the finished rim.

3. A wheel according to claim 1 or claim 2 wherein the rim is of the drop-centre type and the wheel centre is welded to the rim under the well thereof.

4. A method of manufacturing a wheel, comprising: (a) extruding a length of light alloy material with a transverse section of varying thickness; (b) forming said length into a circle and welding the free ends thereof together to form a wheel rim; (c) forging or casting a light alloy wheel centre; (d) establishing a circumferential welded connection between the rim and the centre to form the wheel.

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

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Wheels This invention relates to wheels and more particularlyto wheels made from light alloy. Normally light alloy wheels are cast in one piece. In rare instances, the part of the rim which is cast last is not entirely sound so that, in service, there may be a slow air leak through the rim and the tyre deflates over a numberofdays. It is an object of the present invention to improve the manufacture of light alloy wheels in the manner described hereinafter. According to the invention we provide a wheel having: A. A rim consisting of a length of light alloy material which has been extruded with a transverse cross-section of varying thickness and which has then been circled and had its free ends welded together; B. A light alloy centre which has been forged or cast, and C. At least one circumferential welded connection between the rim and the centre. Since the rim is made from a length of extruded material it has greater integrity than a cast rim so that there is freedom from leakage of the type described above. The invention allows greater design flexibility because one can have a standard rim and different styled centres which fit the same rim. The wheel can be made lighter than if it is cast in one piece. Moreover, the wheel can be manufactured at reduced cost. Preferably, the length of material which forms the rim is extruded with a cross-sectional shape which is substantially that of the finished rim. The rim may be a drop centre rim and the wheel centre may be welded to the rim under the well. The centre may be formed by conventional casting techniques or by "squeeze" casting in which molten metal is placed in a die and is maintained under pressure during solidification. The invention will now be described in detail by way of example with reference to the accompanying drawings in which: FIGURE 1 is a partial section through a wheel embodying the invention, and FIGURE 2 is a partial elevation on the nave face of the wheel, i.e. in the direction of the arrow 2 in Figure 1. The wheel comprises a rim 10 and a centre 11. The rim is formed as a length of extruded light alloy, the rim having a well 12, a first bead seat 13, a ledge 14 between the well and the first bead seat and second bead seat 15. Tyre retaining flanges 16 and 17 are provided at the axially outer ends of the rim section. It will be noted that the rim has a varying thickness and is particularly strengthened at 18 at the junction between the bead seat 15 and the tyre retaining flange 17. There is also thickened portion 19. The rim is extruded as a single length and is circled and is then flash butt welded at 20 as shown in Figure 2. Preferably the rim is extruded in its final cross-sectional shape. The centre 11 is cast or forged as a single piece of light alloy and is provided with a central aperture 21 to receive a hub and a plurality of bolt holes 22. The centre has a number of integral spokes 23 and at its outer periphery has a first flange 24 which fits under the well 12. A circumferential weld 25 connects the rim and the centre. There is also an L-shaped flange 26 which fits within the rim, one limb 27 of the flange 26 engaging the outer surface of one of the well walls and the other limb 28 of the flange engaging underthe bead seat 15. It will be noted that there is a clearance 29 between the L-shaped flange 26 and the rim. We have found that the wheel can be manufactured more cheaply than a single cast wheel. There is greater flexibility in design because the off-set, the distance indicated by the arrow O in Figure 1 may be changed comparatively easily using the same rim and in some circumstances the same centre. The extruded rim has more integrity than a cast rim because of its method of manufacture. CLAIMS

1. Awheelcomprising: A. a rim consisting of a length of light alloy mat erialwhich has been extruded with a transverse cross-section of varying thickness and which has then been circled and had its free ends welded together; B. a light alloy centre which has been forged or cast; and C. at least one circumferential welded connection between the rim and the centre.

2. A wheel according to claim 1 wherein said length has been extruded with a cross-sectional shape which is substantially that of the finished rim.

3. A wheel according to claim 1 or claim 2 wherein the rim is of the drop-centre type and the wheel centre is welded to the rim under the well thereof.

4. A method of manufacturing a wheel, comprising: (a) extruding a length of light alloy material with a transverse section of varying thickness; (b) forming said length into a circle and welding the free ends thereof together to form a wheel rim; (c) forging or casting a light alloy wheel centre; (d) establishing a circumferential welded connection between the rim and the centre to form the wheel.