GB2299556A

GB2299556A - Extruded wheel carrier

Info

Publication number: GB2299556A
Application number: GB9506347A
Authority: GB
Inventors: Richard Alan Rackham
Original assignee: Lotus Cars Ltd
Current assignee: Lotus Cars Ltd
Priority date: 1995-03-28
Filing date: 1995-03-28
Publication date: 1996-10-09
Also published as: GB9506347D0

Abstract

A wheel carrier for a vehicle which comprises the steps of extruding material 18 through a die 10, 11, 12 with the die 10, 11, 12 defining a cross-section of a component of the wheel carrier to produce an elongate member 21 and then slicing it into a plurality of the extruded components.

Description

WHEEL CARRIER AND A METHOD OF MANUFACTURE OF THE SAME The present invention relates to a wheel carrier and to a method of manufacture of the same.

In the specification where reference is made to a wheel carrier, reference is made to that part of a vehicle suspension system which carries a vehicle wheel and to which are connected the suspension components by which the wheel is connected to the vehicle body (e.g. wishbone suspension arms).

Generally the bearing arrangement of a vehicle wheel is provided in or on the wheel carrier. The wheel carrier is sometimes called a suspension upright.

Wheel carriers are typically cast iron in the prior art. Cast iron components are typically heavy and the casting procedure is not an inexpensive procedure.

In DE-A-4216158 there is described how the centre part of a wheel can be made by extruding aluminium, in order that a decorative pattern can be produced.

However, this extruded wheel would have been connected to a standard wheel carrier, conventional in the prior art.

The present invention provides a wheel carrier for a vehicle which comprises an extruded component.

The wheel carrier of the present invention has the advantage that it is at least partly made simply and cheaply by an extrusion method.

The present invention also provides a method of manufacture of a wheel carrier for a vehicle comprising the step of extruding material through a die with the die defining a cross-section of a component of the wheel carrier.

A preferred embodiment of a wheel carrier according to the invention and a preferred method of manufacturing a wheel carrier according to the invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a first stage in a preferred method of manufacture according to the present invention Figure 2 shows a second stage in the method of manufacture of a preferred embodiment Figure 3 shows an elongated extruded member produced after the second stage of the preferred method illustrated in Figure 2 Figure 4 shows a third stage in the preferred method of manufacture Figure 5 shows an extrusion made during the preferred method of manufacture Figure 6 is an exploded perspective view of a wheel carrier assembly which includes an extrusion in accordance with the preferred embodiment of the present invention In Figure 6 there can be seen a wheel carrier according to the present invention. The wheel carrier comprises an extrusion 50 made of an alloy of aluminium.

The extrusion 50 has a central circular aperture 51 which in use receives a bearing arrangement 52. A wheel hub 53 for a vehicle wheel is rotatably mounted in use in the bearing arrangement 52. The vehicle wheel itself is mounted on the wheel hub 53 by means of bolts. It can be seen that if a cross-section is taken through the extrusion 50 in a plane perpendicular to the axis of rotation of wheel mounted on the extrusion 50, then this cross-section will be quite complex in nature. The complex cross-section is defined by a die used in the extrusion process of manufacturing the extrusion 50, as will be described later.

The extrusion 50 has a number of apertures defined therethrough. A cool air passage 54 is defined through the extrusion 50. The cool air passage 54 is located immediately behind a curved outer surface of the extrusion 50. Three other apertures 55, 56 and 57 are defined through the extrusion 50 and these apertures are chosen so as to keep the weight of the wheel carrier 50 to a minimum.

The extrusion 50 has two tapped holes 58 and 59 which enable a disc brake pad assembly 61 to be connected to the wheel carrier 50 by means of bolts such as 60. The disc brake pad assembly 61 and the wheel carrier 50 define between them a cool air passage when the disc brake pad assembly 61 is connected to the extrusion 50. This cool air passage along with the cool air passage 54 already described ensure that there is sufficient passage of air across brake pad and a brake disc for cooling of the brake pads and the brake disc.

Two tapped bores 62 and 63 are provided at the upper portion of the extrusion 50 and enable a member 64 of the wheel carrier to be bolted to the extrusion 50, the member 64 being bolted to the side of the extrusion 50 opposite to the carried wheel. The member 64 is a member which is machined from a suitable metal and which has mounting points 65 and 66 which enable connection of the upper arms of a double wishbone suspension arrangement to be connected to wheel carrier. The member 64 is bolted to the extrusion 50 by means of bolts such as 67. Located between the member 64 and the extrusion 50 is a shim 68. This shim 68 is important since it enables adjustment of the suspension arrangement very easily.

Use of a different thickness of shim can alter the suspension geometry when the suspension is fully assembled. Different shims can be chosen to give different suspension geometries, as required.

The wheel carrier has a member 69 which has mounting points for the lower arms of a double wishbone suspension arrangement and the member 69 can be bolted to the extrusion 50 by means of bolts such as bolt 70. The member 69 is bolted on the lowermost surface of the extrusion 50. Use of shims between the members 69 and the wheel carrier 50 can enable adjustment of suspension geometry.

The extrusion 50 is manufactured by an extrusion process illustrated by Figures 1 to 5. In Figure 1 there can be seen a series of dies 10 to 15 placed in a preheating oven 16. The dies 10 to 15 are heated up to a required temperature for the extrusion process.

Once the dies have been sufficiently heated, then three dies 10, 11 and 12 are placed together in a die set, as illustrated in Figure 2. The die set is heated by a source of heat 17.

Feedstock 18 is forced through the die set by means of a hydraulic ram 19. The feedstock 18 is composed of aluminium alloy and the feedstock 18 is heated by the source of heat 17 before it enters the die set.

The die 10 takes the feedstock 18 from its original cross-section to a first intermediate crosssection. The die 11 then takes the aluminium alloy from the first intermediate cross-section to a second intermediate cross-section. The die 12 then takes the aluminium alloy from a second intermediate crosssection to the final desired cross-section. The aluminium alloy is drawn out of the final die 12 by a hydraulic ram 20. It is important to draw material out of the die set as well as pushing material into the die set in order to ensure accuracy of shape of the extruded material and also to avoid build up of material at the exit of die 12.

Typically the material extruded from the die 12 will be an elongate member of 25 metres length. This is shown in Figure 3. The elongate member is then divided into five smaller elongate members, each of 5 metres length.

The aluminium alloy in the 5 metre length elongate members is of an unstable temper. The five elongate lengths of 5 metres are all placed in an oven 26, as can be seen in Figure 4. The 5 elongate members 21-25 are then heat treated until they reach a stable temper. After this, each elongate member is removed from the oven 26 and in Figure 5 there is shown the elongate member 21 when removed from the oven.

The elongate member 21, which is now of a stable temper, is then sliced into a plurality of extrusions such as the extrusions 50, already described. The dotted lines in Figure 5 indicate the planes through which the elongate member 21 is sliced.

The edges of the extrusions cut from the elongate length 21 will be deburred, by tumbling or machining.

Then each extrusion will be anodised in order to provide corrosion protection. If desired, each component can be coloured by the anodising process.

Once anodised, the material will be machined in order to bring it to its final state. For instance, although the die 12 imposes on the cross-section of the extrusion a central round aperture for receiving bearings for a wheel, the round aperture will not be 100% accurate and therefore the aperture will be slightly rebored in order to provide an accurate aperture 51. Also, various tapped bores (e.g. 58, 59, 62,63) will be drilled into the extrusion 50 in order that the components mentioned earlier can be attached to the extrusion 50.

It will be appreciated that the present invention provides a lightweight wheel carrier and that the method and manufacture provides a cost effective and cheap method of producing the wheel carrier, the method of manufacture intrinsically producing a wheel carrier which has many desired features of shape and configuration which do not require separate machining operations.

Claims

CLAIMS:

1. A wheel carrier for a vehicle which comprises a extruded component.

2. A wheel carrier as claimed in claim 1 wherein the extruded component is comprised of aluminium or an alloy of aluminium.

3. A wheel carrier as claimed in claim 1 or claim 2 wherein the extruded component has a cross-section defined by a die used during manufacture of the component, the defined cross-section extending substantially perpendicular to an axis of rotation of a wheel mounted to the wheel carrier when the wheel carrier is in use.

4. A wheel carrier as claimed in any one of the preceding claims wherein the extruded component has a plurality of apertures defined therethrough, each aperture being defined during extrusion by a die.

5. A wheel carrier as claimed in any one of the preceding claims wherein the extruded component comprises an aperture for receiving a bearing arrangement for mounting a wheel.

6. A wheel carrier as claimed in any one of the preceding claims comprising a first member attachable on the extruded component, which first member has attachment means which enable attachment of a suspension arm to the wheel carrier; connection means for attaching the first member to the wheel carrier; and spacer means intermediate the first member and the extruded component, the spacer means operating to define a suspension geometry when the wheel carrier is pivotally connected to a vehicle by the suspension arm.

7. A wheel carrier as claimed in claim 6 wherein the spacer means is a shim.

8. A wheel carrier as claimed in any one of the preceding claims wherein the extruded component has two substantially flat faces, one face facing a wheel when the wheel is carried by the wheel carrier and the other face facing away from the wheel, and a plurality of apertures extending through the extruded component from one face to the other, the apertures having been defined by a die during extrusion of the extruded component.

9. A wheel carrier as claimed in claim 8 wherein the extruded component has a surface joining the two flat faces, which surface has flat portions and curved portions, at least some portions of the surface having been defined by the die during extrusion of the extruded component.

10. A method of manufacture of a wheel carrier for a vehicle comprising the step of extruding material through a die with the die defining a cross-section of a component of the wheel carrier.

11. A method of manufacture as claimed in claim 8 wherein the material is extruded through the die to form an elongate extrusion and the elongate extrusion is then sliced through a plurality of planes perpendicular to the longitudinal axis of the elongate member in order to define a plurality of components for a plurality of wheel carriers.

12. A method of manufacture as claimed in claim 10 or claim 11 where the die is used to define a plurality of apertures extending through the extruded component.

13. A method of manufacture as claimed in claim 12 wherein the die defines an aperture through the extruded component which is used as a housing for a bearing arrangement in the finished wheel carrier.

14. A method of manufacture as claimed in claim 12 or claim 13 wherein the die defines an aperture which serves as an air passage for cooling air in the finished wheel carrier.

15. A wheel carrier substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

16. A method of manufacture of a wheel carrier substantially as hereinbefore described with reference to and as shown in the accompanying drawings.