Vehicle components and sacrificial ribs

Abstract

A structural component 1 is provided for a vehicle designed for driving off-road on rough terrain. The component 1, such as the lower control arm of a suspension system, is formed from aluminum, aluminum-alloy or other light-weight material and provided on its underside with a parallel arrangement of chamfered ribs 5 which extend in the direction of travel of the vehicle. The spacing between adjacent ribs 5 is less than or equal to 10 mm so as to prevent underlying rocks and stones 7 from impacting, and thereby abrading the inner surface 3 of the component 1. The ribs 5 are provided as sacrificial elements and will become eroded in use until they no longer provide the desired protection of the inner surface 3. The extent of abrasion of the ribs 5 can be ascertained by a visual inspection of the underlying surface of the vehicle, and, if necessary, the component 1 can be replaced.

Claims

1. A lower control arm of a suspension system for a vehicle, comprising: a plurality of projections on an underlying surface of the lower control arm that, in use, opposes a surface over which the vehicle is travelling; wherein the plurality of projections comprise sacrificial elements and are configured to project substantially from the underlying surface of the lower control arm toward the surface over which the vehicle is travelling, wherein the plurality of projections is configured so that any impact erosion in driving the vehicle is concentrated on the plurality of projections to protect the underlying surface of the lower control arm, so that the partial, or even total, removal of the plurality of projections by abrasion does not impact the integrity or function of the lower control arm.

2. A lower control arm as claimed in claim 1, wherein the underlying surface and the plurality of projections are formed integrally.

3. A lower control arm as claimed in claim 1, and made from a material selected from: (a) aluminium; (b) an aluminium alloy; (c) magnesium; and (d) a magnesium alloy.

4. A lower control arm as claimed in claim 1, wherein the lower control arm is a cast component.

5. A lower control arm as claimed in claim 1, wherein the plurality of projections extend across a sacrificial region of the underlying surface.

6. A lower control arm as claimed in claim 5, wherein each of the plurality of projections has a substantially planar surface extending across most of a width of each projection.

7. A lower control arm as claimed in claim 1, wherein the plurality of projections are configured to protect an inner surface of the underlying surface.

8. A lower control arm as claimed in claim 1, comprising a further sacrificial region on an underlying surface that faces the front or rear of the vehicle.

9. A lower control arm as claimed in claim 1, comprising a sacrificial region on an underlying surface that opposes a surface over which the vehicle is travelling, wherein each projection of the plurality of projections extends in a direction substantially along a driving direction of the vehicle.

10. A vehicle comprising a lower control arm as claimed in claim 1.

11. A lower control arm as claimed in claim 1, wherein each projection comprises a rib extending along the underlying surface.

12. A lower control arm of a suspension system for a vehicle, comprising: an underlying surface of the lower control arm that opposes to a surface over which the vehicle is travelling, wherein the underlying surface of the lower control arm is configured to directly face the surface over which the vehicle is travelling; an excess member provided on the underlying surface of the lower control arm; and a plurality of grooves provided in the excess member extending up to the underlying surface of the lower control arm so as to form a plurality of projections extending in a direction substantially toward the surface over which the vehicle is travelling; wherein the projections form a sacrificial region configured to protect the underlying surface of the lower control arm from an object which is larger than a gap between the adjacent projections when receiving an impact on the projections from the object.

13. A lower control arm as claimed in claim 11, wherein each rib has a substantially planar surface extending across most of a width of each rib.

14. A lower control arm of a suspension system for a vehicle, comprising: a plurality of projections on an underlying surface that, in use, opposes a surface over which the vehicle is travelling; wherein the plurality of projections comprise sacrificial elements and are configured to project substantially toward the surface over which the vehicle is travelling, wherein the plurality of projections is configured so that any impact erosion in driving the vehicle is concentrated on the plurality of projections to protect the underlying surface, wherein each projection comprises a rib extending along the underlying surface and a pitch of the ribs is less than 20 mm.

15. A lower control arm as claimed in claim 11, wherein each rib has a width of about 10 mm, and wherein a spacing between adjacent ribs is less than 10 mm.

16. A lower control arm as claimed in claim 11, wherein each rib has a height of about 3 mm.

17. A lower control arm as claimed in claim 11, wherein an end of each rib is chamfered.

18. A lower control arm as claimed in claim 11, wherein each rib has a trapezoidal cross section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 is a schematic cross-sectional view of a component for a vehicle formed with an excess thickness of material on the underside;

(3) FIG. 2 is a schematic cross-sectional view of a component for a vehicle in accordance with an embodiment of the present invention prepared from the structural component shown in FIG. 1;

(4) FIGS. 3 and 4 illustrate views of the underside of a lower suspension arm of a vehicle in accordance with an embodiment of the present invention; and

(5) FIG. 5 illustrates a section view of the lower suspension arm in FIGS. 3 and 4 through line A-A (as indicated in FIG. 3).

DETAILED DESCRIPTION

(6) Referring to FIG. 1, which is not drawn to scale, a structural component 1 for a vehicle, such as the lower control arm of a suspension system of the vehicle, is formed from aluminium, an aluminium alloy or other suitable light-weight material. The arm has an underside with an underlying surface 10 which, in use on a vehicle, forms part of the underlying surface of the vehicle, and will face the road surface. The underside has an excess thickness 2 of material. The thickness of the excess material 2 is typically 3 mm. The expression excess thickness is used to mean that the component 1 would be able to perform its normal function in the absence of this excess thickness of material 2. Reference numeral 3 indicates the surface of a conventional structural component for a vehicle which is formed without this excess material 2. Embodiments of the present invention seek to prevent this inner surface 3 from being eroded by abrasion due to impact with underlying rocks and stones and other debris typically encountered during driving of the vehicle, particularly when driving off-road.

(7) As shown in FIG. 2, in an embodiment of the invention, also not drawn to scale, the underlying surface 10 has a number of surface features 4, 5. The surface features comprise a number of substantially parallel grooves 4 which are cut into the excess material 2 to form a generally parallel array of projections or ribs 5, each rib having a width of about 10 mm. The cutting may be performed by a milling process. The structural component may alternatively be formed with the surface configuration already applied, for example using a casting process. The ribs 5 are formed on the component 1 such that, when the component is fitted on the vehicle, the ribs 5 extend along the direction of travel of the vehicle (i.e. perpendicular to the plane of the drawing) between front and rear ends of the component, relative to the vehicle (i.e. along the front-to-rear vehicle axis). The ribs 5 are formed with substantially flat upper surfaces 6 having chamfered edges (not shown). The spacing between adjacent pairs of ribs 5 is less than or equal to 10 mm, so as to prevent small stones, such as the stone 7 shown in the drawing, from impacting the inner surface 3 of the component 1 and thereby potentially damaging the component 1.

(8) The ribs 5 formed from the layer of excess material 2 are provided as sacrificial elements, since most impacts from and/or direct contact with underlying rocks and stones will be borne by the ribs 5, and not by the inner surface 3 of the component 1.

(9) The frequent impacts with underlying rocks, stones and other debris causes the ribs 5 gradually to become worn in use, and eventually the ribs 5 will become abraded to such an extent that the inner surface 3 will become exposed to such impacts.

(10) However, the extent of erosion of the component 1 can readily be assessed by a visual inspection of the underside of the vehicle. When the ribs 5 have become eroded to such an extent that the inner surface 3 is insufficiently protected by the ribs 5, this provides an indication that the component 1 requires replacement, in the same manner that tyres are inspected regularly to ensure that the tread is of a sufficient depth. However, a major difference between the embodiment of the present invention and the provision of tread on tyres is that the ribs 5 are formed from material which is excess to that required for the component 1 to perform its function, whereas the full depth of tread provided on tyres serves to increase the grip of the tyres on the road surface. In this way, it is possible to ensure that the inner surface 3 of the component 1 remains intact and that the component 1 can therefore perform its intended function in the vehicle, even when some or all of the excess material 2 is eroded.

(11) FIGS. 3 and 4 illustrate two different views of a lower control arm 8 of a suspension system incorporating the ribs 5 described above and illustrated schematically in FIG. 2, and FIG. 5 is a section view of the lower control arm 8 in FIGS. 3 and 4 through the line A-A. As shown in FIGS. 3, 4 and 5, each rib 5 is chamfered both along the sides and at the ends. Although advantageous embodiments of the present invention have been described above, it will be appreciated that numerous variations and modifications may be made without departing from the scope of the invention which is defined solely by the claims.

(12) Although the embodiment above relates to a structural component the skilled man would understand that the invention could equally be applied to any component which, in use, defines, at least in part, an underlying surface of the vehicle which is subjected to impact erosion, such as a fuel tank of the vehicle, one or more cross members for cradles, any element of a suspension system which, in use, defines, at least in part, an underlying surface of the vehicle which is subjected to impact erosion, an element of the exhaust system, a tow bar, a transmission, one or more brackets associated with a transmission, a transfer case, or a rear differential.