GB2069945A

GB2069945A - Stabilizer for power driven vehicle

Info

Publication number: GB2069945A
Application number: GB8006085A
Authority: GB
Original assignee: Hoesch Werke AG
Current assignee: Hoesch Werke AG
Priority date: 1978-10-25
Filing date: 1980-02-22
Publication date: 1981-09-03
Also published as: GB2069945B; DE2846445A1; DE2846445C2; FR2476781A1; FR2476781B3

Abstract

In a U-shape tubular stabilizer for a power driven vehicle the transitional regions joining the limbs and the centre portion of the tube are provided with reinforcements which can extend into the limbs and the centre portion of the stabilizer beyond the arcuate transitional regions. The reinforcements are formed by external or internal thickenings (4) of the tube and/or by inserts, which may be solid or tubular. <IMAGE>

Description

SPECIFICATION Stabilizer for power driven vehicle The invention relates to a stabilizer for a power driven vehicle.

Such stabilizers can be formed by bending a bar to a "U" shape, and reinforcements can be provided in the transitional regions between the limbs and the central part of the bar. The reinforcements can be extended into the limbs and the central part of the bar beyond the transitional regions. The use of tubing in the manufacture of such stabilizers is known, because this improves the utilization of raw material and at the same time saves weight.

These stabilizers usually have the form of bars bent into a "U" shape and are subjected to alternating deformations. The centre portion of the stabilizer is subjected predominantly to torsional stress, whilst the two limbs of the stabilizer are predominantly subjected to bending stress. The structural design of the stabilizer determines that a stress composed of torsional and bending components acts at the position of the transitional regions or radii between the limbs and the base or centre portion of the stabilizer. Strength tests made on the stabilizers under operating conditions have shown that this composite stress limits the useful life of the stabilizer. In fact, stabilizers having a constant circular cross-section fail initially due to fracture at the transition radius.

Fractures at these positions are particularly dangerous in stabilizers, since they also normally assume wheel guiding functions. In normal practice the point of bearing support of the bar is located at the base thereof, and a fracture at the radius therefore leaves the wheel without any guiding control.

It has moreover been shown that in stabilizers made from tubing the quality of the internal surface of the tube is to a large extent responsible for the useful life of the component. Whilst a high quality surface is relatively simple to achieve for the outer surface of the tube by the use of centreless grinding and shot blasting operations, and any faults such as cracks can eventually be eliminated by suitable testing programmes, corresponding steps in respect of the internal surface can either not be employed at all or can be used only at high expense. The result of this is that in practice only tubing having a relatively large wall thickness can be used for stabilizers, given a need for reducing the stresses at the internal diameter of the tube.

It would consequently be advantageous to provide a stabilizer made of tubing, which, whilst having a relatively small wall thickness and therefore a good utilization of material, nevertheless also has an extended useful life.

The invention accordingly provides a stabilizer for a power driven vehicle comprising a tube bent at least approximately into a U-shape, the tube having reinforcements at the bends comprising thickened wall portions and/or inserts.

Advantageously, the inserts comprise lengths of tubing, which may be split, or solid material.

The thickened portions may be internal and/or external, and with the object of increasing the useful life of the stabilizer, internally thickened portions may be suitably machined at the inner diameter.

The invention is further described below by way of example with reference to the accompanying drawing, in which: Fig. 1 is a partial sectional view of a first stabilizer embodying the invention; and Fig. 2 is a like view of a second stabilizer embodying the invention.

Each of the stabilizers 1 illustrated comprises a tube 2 bent into a U-shape, with an arcuate transitional region between the base and each limb. Only the part of each stabilizer 1 in the vicinity of one of the transitional regions is shown in the drawing. The stabilizer of Fig. 1 is provided with a tubular insert 3 extending over the transitional region and beyond, into the rectilinear portions of the tube 2.

When producing the stabilizer, this insert 3 is forced into the tube 2 whilst the latter is still in the rectilinear condition. By this step, the insert 3 serves to support the cross-section of the tube 2 and to prevent wall collapse whilst bending.

Secondly the insert 3 performs its supporting function when the stabilizer is in the bent condition, whereby the useful life of the stabilizer is increased.

The insert 3 may be of solid cross-section instead of hollow cross-section as shown in the drawing. In order to ensure seating of the insert 3, it may consist of longitudinally split tubing.

The material of the insert 3 may be spring steel or even structural steel.

In the stabilizer of Fig. 2, the tube 2 is provided, in the transition region, with a thickened portion 4 which extends into the rectilinear regions of the tube.

This thickened portion 4 is formed by internal swaging at the transition region of the tube 2 from which the stabilizer is produced.

Other forms of the stabilizer of the invention are provided in addition with externally th;ckened portions or with externally thickened portions only.

The increase in the wall thickness makes possible a reduction in the stressing of the stabilizer as well as an improved shape stability when bending. Apart from this, by the use of mechanical machining, in particular metal removal machining operations, performed on the still unbent tube 2 in the transition regions, it is possible to produce a high quality surface finish in a particularly economical manner, which will also contribute to an improvement in the useful life of the stabilizer.

1. A stabilizer for a power driven vehicle comprising a tube bent at least approximately into a U-shape, the tube having reinforcements at the bends comprising thickened wall portions and/or

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Stabilizer for power driven vehicle The invention relates to a stabilizer for a power driven vehicle. Such stabilizers can be formed by bending a bar to a "U" shape, and reinforcements can be provided in the transitional regions between the limbs and the central part of the bar. The reinforcements can be extended into the limbs and the central part of the bar beyond the transitional regions. The use of tubing in the manufacture of such stabilizers is known, because this improves the utilization of raw material and at the same time saves weight. These stabilizers usually have the form of bars bent into a "U" shape and are subjected to alternating deformations. The centre portion of the stabilizer is subjected predominantly to torsional stress, whilst the two limbs of the stabilizer are predominantly subjected to bending stress. The structural design of the stabilizer determines that a stress composed of torsional and bending components acts at the position of the transitional regions or radii between the limbs and the base or centre portion of the stabilizer. Strength tests made on the stabilizers under operating conditions have shown that this composite stress limits the useful life of the stabilizer. In fact, stabilizers having a constant circular cross-section fail initially due to fracture at the transition radius. Fractures at these positions are particularly dangerous in stabilizers, since they also normally assume wheel guiding functions. In normal practice the point of bearing support of the bar is located at the base thereof, and a fracture at the radius therefore leaves the wheel without any guiding control. It has moreover been shown that in stabilizers made from tubing the quality of the internal surface of the tube is to a large extent responsible for the useful life of the component. Whilst a high quality surface is relatively simple to achieve for the outer surface of the tube by the use of centreless grinding and shot blasting operations, and any faults such as cracks can eventually be eliminated by suitable testing programmes, corresponding steps in respect of the internal surface can either not be employed at all or can be used only at high expense. The result of this is that in practice only tubing having a relatively large wall thickness can be used for stabilizers, given a need for reducing the stresses at the internal diameter of the tube. It would consequently be advantageous to provide a stabilizer made of tubing, which, whilst having a relatively small wall thickness and therefore a good utilization of material, nevertheless also has an extended useful life. The invention accordingly provides a stabilizer for a power driven vehicle comprising a tube bent at least approximately into a U-shape, the tube having reinforcements at the bends comprising thickened wall portions and/or inserts. Advantageously, the inserts comprise lengths of tubing, which may be split, or solid material. The thickened portions may be internal and/or external, and with the object of increasing the useful life of the stabilizer, internally thickened portions may be suitably machined at the inner diameter. The invention is further described below by way of example with reference to the accompanying drawing, in which: Fig. 1 is a partial sectional view of a first stabilizer embodying the invention; and Fig. 2 is a like view of a second stabilizer embodying the invention. Each of the stabilizers 1 illustrated comprises a tube 2 bent into a U-shape, with an arcuate transitional region between the base and each limb. Only the part of each stabilizer 1 in the vicinity of one of the transitional regions is shown in the drawing. The stabilizer of Fig. 1 is provided with a tubular insert 3 extending over the transitional region and beyond, into the rectilinear portions of the tube 2. When producing the stabilizer, this insert 3 is forced into the tube 2 whilst the latter is still in the rectilinear condition. By this step, the insert 3 serves to support the cross-section of the tube 2 and to prevent wall collapse whilst bending. Secondly the insert 3 performs its supporting function when the stabilizer is in the bent condition, whereby the useful life of the stabilizer is increased. The insert 3 may be of solid cross-section instead of hollow cross-section as shown in the drawing. In order to ensure seating of the insert 3, it may consist of longitudinally split tubing. The material of the insert 3 may be spring steel or even structural steel. In the stabilizer of Fig. 2, the tube 2 is provided, in the transition region, with a thickened portion 4 which extends into the rectilinear regions of the tube. This thickened portion 4 is formed by internal swaging at the transition region of the tube 2 from which the stabilizer is produced. Other forms of the stabilizer of the invention are provided in addition with externally th;ckened portions or with externally thickened portions only. The increase in the wall thickness makes possible a reduction in the stressing of the stabilizer as well as an improved shape stability when bending. Apart from this, by the use of mechanical machining, in particular metal removal machining operations, performed on the still unbent tube 2 in the transition regions, it is possible to produce a high quality surface finish in a particularly economical manner, which will also contribute to an improvement in the useful life of the stabilizer. CLAIMS

1. A stabilizer for a power driven vehicle comprising a tube bent at least approximately into a U-shape, the tube having reinforcements at the bends comprising thickened wall portions and/or inserts.

2. A stabilizer as claimed in claim 1 wherein the reinforcements extend beyond the bends.

3. A stabilizer as claimed in claim 1 or 2 having the inserts, the inserts comprising lengths of tubing.

4. A stabilizer as claimed in claim 3 wherein the lengths of tubing are longitudinally split.

5. A stabilizer as claimed in claim 1 or 2 having the inserts, the inserts comprising solid material.

6. A stabilizer as claimed in any preceding claim having the thickened wall portions, the thickening being internal.

7. A stabilizer as claimed in claim 6 wherein the thickened wall portions are machined to an internal diameter.

8. A stabilizer as claimed in any preceding claim wherein the tube is of substantially constant external diameter over at least the reinforcements.

9. A stabilizer for a power driven vehicle substantially as herein described with reference to Fig. 1 or Fig. 2 of the accompanying drawings.