GB2291629A

GB2291629A - Vehicle suspension strut mounting assembly

Info

Publication number: GB2291629A
Application number: GB9415288A
Authority: GB
Inventors: Barry Smith
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1994-07-23
Filing date: 1994-07-23
Publication date: 1996-01-31
Also published as: GB9415288D0

Abstract

An assembly for mounting a suspension strut 2 in a motor vehicle comprises a reinforcing plate 4 for mounting on the body 6 of the vehicle, and an elongate suspension strut 2. The strut 2 has a shock absorber and it has means for connecting one end to the frame of the vehicle so as substantially to prevent the strut 2 turning about its longitudinal axis. The strut 2 and the reinforcing plate 4 are provided with complementary screw threads 14, 16 so that the strut 2 may be releasably secured to the reinforcing plate 4 by interengagement of the screw threads 14, 16. The invention also provides a strut for securing to the reinforcing plate, and a motor vehicle which has mounted in it an assembly or strut as described. <IMAGE>

Description

VEHICLE SUSPENSION STRUT MOUNTING ASSEMBLY The present invention relates to an assembly for releasably mounting a suspension strut in the body of a motor vehicle.

Suspension struts are used for mounting the body of a motor vehicle to the vehicle frame. Each strut is provided with a shock absorber to reduce up and down movement of the vehicle body relative to the road.

In -one known mounting assembly, a suspension strut is connected to a cast hub and knuckle, or a strut,. adjacent to a wheel, at one end, and to a body panel at its other end. The connection to the body panel is typically effected by locating the strut so that the piston rod of the shock absorber protrudes through a hole in the body panel. An anti-failure plate is placed around the exposed end of the piston rod, and secured on the piston rod by a lock nut. The anti-failure plate is of a size which will not pass through the hole in the reinforcing plate and/or in the body panel. It therefore serves to limit the downward movement of the piston rod relative to the vehicle body. A reinforcing plate is disposed between the strut and the underside of the body panel. The reinforcing plate is typically mounted on the body panel by means of bolts and weld nuts on the body, or by welding.

Under most conditions the body of the vehicle presses down on the strut by virtue of the vehicle's weight, and the piston rod extends through the body panel so that the anti-failure plate does not make contact with the body panel. The shock absorber acts to smooth out up and down movement of the body when the vehicle is in motion, and the anti-failure plate only makes contact with the body panel if the shock absorber is unusually extended, whereupon the anti-failure plate acts to prevent the piston rod from becoming withdrawn from the body panel.

A problem with this known form of assembly is that it is necessary to gain access to the upper surface of the body panel to undo the lock nut which secures the anti-failure plate to the piston rod if the strut is to be removed without also removing the reinforcing plate. If the reinforcing plate is welded to the body its removal is impractical, and if it is bolted to the body it may not be easy to get access to the bolts to undo them. .The upper surface of the body panel may not be readily accessible, and vehicle manufacturers may wish to design motor vehicles in which the upper surface of the body panel is inaccessible because of the presence of other assemblies or structural components.

It is therefore desirable to be able to mount and demount a suspension strut in a body panel of a motor vehicle without accessing the upper surface of the body panel, and without removing the reinforcing plate.

According to the present invention there is provided an assembly for mounting a suspension strut in a motor vehicle, which assembly comprises a reinforcing plate for mounting on the body of the vehicle, and an elongate suspension strut which has a shock absorber and which has means at one end for connecting the strut to the vehicle frame so as substantially to prevent turning of the strut about its longitudinal axis, wherein the reinforcing plate and the suspension strut are provided with complementary screw threads so that the strut may be releasably secured to the reinforcing plate by interengagement of the screw threads.

Because the strut may be secured to the reinforcing plate by interengagement of screw threads, there is no need for a lock nut on the upper surface of the body panel, and hence no need to gain access to the upper surface of the body panel. The reinforcing plate may also remain mounted on the body panel whilst the strut is removed.

The screw threads preferably have surfaces which are resistant to corrosion. For example aluminium or a structural plastics material.

Apart from the screw threads, the suspension strut and reinforcing plate may be of any suitable conventional construction, for example the type of strut known as a MacPherson strut may be used. The assembly may therefore be mounted in motor vehicles of existing design without the need to modify the vehicle design.

In a preferred embodiment the shock absorber has a piston rod which is secured to an anti-failure plate, and the strut has means for limiting the downward movement of the anti-failure plate, and hence of the piston rod relative to the vehicle body, when the strut is mounted in the vehicle. The limiting means may be, for example, an inwardly directed radial lip. The anti-failure plate may be secured to the end of the piston rod by conventional means, for example by means of a lock nut.

Because downward movement of the piston rod is limited by limiting means on the strut, rather than the body panel, the strut and the anti-failure plate may be mounted and demounted in the body panel without accessing the upper surface of the body panel.

Any suitable shock absorber may be used. The shock absorber may comprise, for example, a cylinder for mounting with respect to the strut, and a piston rod which is mounted in the cylinder and which is movable with respect to the cylinder. If an external force is applied to the piston rod it moves further into the cylinder and compresses a gas in the cylinder, and when the external force is removed, the pressurised gas forces the piston rod further out of the cylinder. The strut will typically also be provided with one or more springs to smooth out the up and down movement of the vehicle body with respect to the frame.

The assembly may conveniently be mounted in the vehicle as follows. The strut is mounted in the reinforcing plate by interengagement of the screw threads, and one end of the strut is connected to the vehicle frame by well known conventional means. The reinforcing plate is then mounted on a body panel by conventional means, for example by welding or by means of bolts and weld nuts on the body panel. Other orders of assembly are also possible, provided that the strut is mounted in the reinforcing plate before being connected to the vehicle frame.

Because the connection to the frame does not permit any substantial turning of the strut about its longitudinal axis, the strut cannot become unscrewed from the reinforcing plate whilst it is connected to the frame.

The suspension strut may be sold separately from the reinforcing plate, and the invention therefore also provides an elongate suspension strut for a motor vehicle, the strut having a shock absorber and means at one end for connecting the strut to the vehicle frame so as substantially to prevent turning of the strut about its longitudinal axis, and a screw thread for engaging with a complementary screw thread on a reinforcing plate for mounting on the vehicle.

The invention will now be further described, by way of example, with reference to the following drawings in which: Figure 1 is an exploded part sectional view of a known assembly for mounting a suspension strut in a motor vehicle; and Figure 2 is a part sectional view of an assembly for mounting a suspension strut in a motor vehicle in accordance with the present invention.

In the known assembly shown in Figure 1 the piston rod 8 of a shock absorber in a suspension strut 2 is adapted to protrude through a hole in a reinforcing plate 4 which is mounted around a hole in a vehicle body panel'6. A lock nut 12 secures an anti-failure plate 10 to the piston rod 8, and thereby secures the piston rod 8 and the strut 2 to the body panel 6. The strut 2 is connected at its lower end to the frame of the vehicle (not shown). In order to remove the strut 2 from the panel 6 it is necessary either to undo the lock nut 12, or to demount the reinforcing plate 4 from the panel 6. In order to remove the lock nut the upper surface of the panel 6 must be accessible, and in order to demount the reinforcing plate 4 it must be releasably mounted, and the bolts or other releasable means must be accessible.

In the assembly shown in Figure 2 equivalent parts have been given the same numbering as for Figure 1. The reinforcing plate 4 is provided with a first screw threaded member 16 which is a complementary fit for a second screw threaded member 14 which is mounted on the strut 2. The strut 2 may therefore be releasably mounted on the reinforcing plate 4 by interengagement of the screw threaded members 14 and 16. The screw threaded member 14 is provided with an inwardly directed radial flange 18 which serves to limit the downward movement of the antifailure plate 10 which is secured to the piston rod 8 by a lock nut 12.

The strut 2 may therefore be secured in and removed from the body panel 6 without either gaining access to the upper surface of the panel 6, or removing the reinforcing plate 4.

The invention therefore provides a convenient assembly for releasably mounting a suspension strut in the body of a motor vehicle.

Claims

1. An assembly for mounting a suspension strut in a motor vehicle, which assembly comprises a reinforcing plate for mounting on the body of the vehicle, and an elongate suspension strut which has a shock absorber and which has-means at one end for connecting the strut to the vehicle frame so as substantially to prevent turning of the strut about its longitudinal axis, wherein the reinforcing plate and the suspension strut are provided with complementary screw threads so that the strut may be releasably secured to the reinforcing plate by interengagement of the screw threads.

2. An assembly as claimed in claim 1, wherein the shock absorber has a piston rod which is secured to an antifailure plate, and wherein the strut has means for limiting the downward movement of the anti-failure plate.

3. An assembly as claimed in claim 2, wherein the movement limiting means comprise an inwardly directed radial flange.

4. An assembly as claimed in any one of the preceding claims, wherein the screw threads have surfaces which are resistant to corrosion.

5. An elongate suspension strut for a motor vehicle, the strut having a shock absorber and means at one end for connecting the strut to the vehicle frame so as substantially to prevent turning of the strut about its longitudinal axis, and a screw thread for engaging with a complementary screw thread on a reinforcing plate mounted on the vehicle.

6. A motor vehicle in which is mounted an assembly or suspension strut as claimed in any one of the preceding claims.

7. An assembly substantially as hereinbefore described with reference to and as shown in Figure 2.