GB2046680A - Improvements in or relating to vehicles - Google Patents

Abstract

A vehicle having roll control means which comprise a connection, e.g. a pretensioned rod 17, at each side of the vehicle between the suspended vehicle chassis frame 1 (or the suspended vehicle body) and an unsuspended axle or an axle mounted assembly of the vehicle. The connections, e.g. the rods 17 and conical rubber springs 20, restrain relative separating movement of the vehicle chassis frame 1 or the vehicle body from the axle 2, 3 by imparting a gradually increasing tension force across the suspension medium 15. <IMAGE>

Description

SPECIFICATION Improvements in or relating to vehicles The present invention relates to vehicles provided with roll control means.

Vehicle roll is caused by lateral forces, such as generated when cornering, producing a turning moment. Roll is in fact particularly apparent with goods vehicles having high bodies as the high centre of gravity in such a vehicle causes an increase in the turning moment. In order to overcome roll, the turning moment must be restrained by the vehicles suspension. In restraining this turning moment, the suspension carries an additional load on one side of the vehicle and less on the other and the attitude of the vehicle to the road surface is therefore affected. A high degree of roll is therefore unacceptable as it affects vehicle stability and hence safety.

To date many commercial vehicles have been fitted with stiff, high rate suspensions that resists roll effectively even under unfavourable conditions, such as fast cornering with heavy and high loads. Stiff suspensions generally however produce inferior ride characteristics than the soft, low rate suspensions now being generally adopted such as taperlead springs, air and rubber. The conventional method of restraining roll effects with low rate suspensions is with an anti-roll bar but this often causes installation difficulties, especially with multi-axle bogie configurations as typically used on transport vehicles.

It is an object of the present invention to provide a vehicle having a simple and effective roll control means.

According to the present invention there is provided a vehicle having roll control means which comprise a connection at each side of the centreline of the vehicle between the suspended vehicle chassis frame or the suspended vehicle body and an unsuspended axle or an axle mounted assembly of the vehicle, which connections restrain relative separating movements of the vehicle chassis frame or the vehicle body from the axle by imparting a gradually increasing tension force across the suspension medium.

As used herein the term axle mounted assembly refers to an axle assembly component which is mounted either directly or indirectly on the axle. Examples of such axle mounted assemblies are trailing links, axle location links, and, in the case of a multi-axle configuration, inter-axle walking beams.

Preferably the connection across the suspension medium is provided by a rod coupled to the frame or body and to an axle or an axle mounted assembly of the vehicle by any suitable means allowing the rod to prevent the relative separating movement by imparting a gradually increasing tension force. Preferably however the rod will locate through aligned apertures provided in facing parts of the frame or body and the axle or axle mounted assembly and the coupling means will comprise springs, preferably conical rubber springs, located over the free ends of the rods and retained in position by suitable abutments on the rods.

The vehicles of the invention may be provided with the roll control means for their front and/or rear axles. The roll control means are particularly effective where the suspension media are soft low rate suspensions, such as of the type mentioned above. More particularly, the roll control means are eminently suitable for use in conjunction with so-called rubber suspension systems having "springs" which are comprised or rubber blocks sandwiched between metal plates and which are loaded in shear and compression. The roll control means are particularly effective when used in conjunction with a rear bogie of s worry incorporating "rubber" springs of the type described.

The invention will be further described by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a vertical sectional view through a two axle rear bogie unit; and Fig. 2 is a view along the line A-A of Fig. 1.

Referring to Fig. 1, there is shown a bogie unit which is mounted on frame members 1 provided at each side of the vehicle. The bogie unit has two axles 2 and 3, each provided with wheels 4. At each side of the vehicle is a longitudinal beam 5 the ends of which are pivotally mounted on depending brackets 6 and 7 provided on the axles '2 and 3 respectively, whereby the axles are connected together. The axles 2 and 3 are mounted at each side of the vehicle on respective torque rods 8 and 9 each having one end pivotally connected to the frame member 1 and the remaining end pivotally connected to respective upstanding brackets 10 and 11 provided on the axles 2 and 3.

Each beam 5 has a central upstanding triangular fillet 12 provided on its upwardly sloping edges with plates 1 2a and 1 2b which also slope upwardly toward each other. The fillet 1 2 locates between two longitudinally spaced blocks 13 and 14 provided on the frame member 1, each of which have a sloping face parallel to the adjacent face flange 1 2a or 1 2b of the block 12 as clearly illustrated in Fig. 1. Two spring units 1 5 are mounted between the adjacent parallel faces of the block 12 and the blocks 13 and 14. Each spring unit 1 5 is of the type comprising blocks of rubber 1 spa sandwiched between metal plates 1 sub, the rubber blocks being subjected to combined shear and compression under load.A rubber buffer 1 6 is provided to prevent excessive overload of the suspension system.

The bogie is provided with roll control means which are shown clearly in Fig. 2 and which comprise, at each side of the vehicle, a pretensioned rod 1 7 locating with slight clearance through aligned apertures is outwardly direqted flanges 1 8 and 1 9 respectively provided on the frame member 1 and the central portion of the face of the fillet 12. The rods 1 7 are each effectively coupled to the beam 5 and the frame 1 by two conical rubber springs 20, the springs 20 being retained on the rods by large plate washers 21 and nuts 22.

For effective operation of the roll control means a slight preload is required in the rods 1 7 when the suspension is fuliy laden. Relative movement of the vehicle body away from the bogie unit will, of course, further increase the tension in the rod in a progressive manner. During fast cornering of the vehicle there will be a tendancy for the vehicle body to roll towards the outside of the bend, i.e.

the frame member 1 at the inside of the bend will tend to move away from the beam 5, and vice versa at the outside of the bend. This tendancy to roll will be restrained by progressively increasing tension in the rod 1 7 on the inside of the bend, and also by the suspension buffer 1 6 at the outside of the bend. The clearance between the rods 17 and the apertures in the flanges 18 and 1 9 allows the apertures to move slightly out of alignment whilst the body rolls slightly, thereby preventing bending stresses in the rods.

It will therefore be seen that the invention provides an effective and simple means of controlling vehicle roll. It will of course be appreciated that the degree of roll control effect is dependent on the distance of the rod 1 7 from the centreline of the vehicle, and the greater this distance the greater will be the roll control effect.

Claims (7)

1. A vehicle having roll control means which comprise a connection at each side of the vehicle between the suspended vehicle chassis frame or the suspended vehicle body and an unsuspended axle or an axle mounted assembly of the vehicle, which connections restrain relative separating movement of the vehicle chassis frame or the vehicle body from the axle by imparting a gradually increasing tension force across the suspension medium.

2. A vehicle as claimed in claim 1 wherein the connection at each side of the vehicle is a rod.

3. A vehicle as claimed in claim 2 wherein each rod is located through aligned apertures provided in flanges on the suspended vehicle chassis frame or the suspended vehicle body and on an unsuspended axle or axle mounted assembly of the yehicle, the ends of the rods have abutments, and the rods are coupled to the flanges by means located between the abutments and the flanges.

4. A vehicle as claimed in claim 3 wherein the means coupling the rods to the flanges are conical springs.

5. A vehicle as claimed in claim 1 wherein the suspension medium comprises suspension units of blocks of rubber sandwiched between metal plates with the rubber blocks being loaded in both shear and compression.

6. A vehicle as claimed in claim 5 which has a rear bogie, the vehicle body or vehicle chassis being suspended on said bogie by said suspension units, and said roll control means are provided in the vicinity of the roll control means.

7. A vehicle having roll control means substantially as hereinbefore described with reference to the accompanying drawings.