AU745053B2

AU745053B2 - Vehicle suspension assembly

Info

Publication number: AU745053B2
Application number: AU30209/00A
Authority: AU
Inventors: David Robert Gordon Bailey
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-05-04
Filing date: 2000-05-01
Publication date: 2002-03-07
Anticipated expiration: 2020-05-01
Also published as: AU3020900A

Description

1 This invention relates to a vehicle suspension assembly.

This invention has particular but not exclusive application to a vehicle suspension system for heavy vehicles such as those often referred to as road transports, and wherein reference will be made to said application. However it will be appreciated that the invention could also be used in the construction of vehicles that are specifically designed to traverse uneven terrain including military and rescue vehicles.

Road transports typically include a long tray on which loads to be carried by the vehicle are supported. The rear end of the tray is usually supported by a pair of 10 parallel vehicle axles. The end portions of the first axle are each attached to the mid- Sportion of a respective leaf spring suspended from the vehicle's chassis. The second or trailing axle is attached to the trailing end portions of two opposing leaf springs, each leaf spring having a leading end portion that is attached to the first axle and a mid-portion that is suspended from the vehicle's chassis. This arrangement is commonly referred to as a lazy axle.

At times when travelling over uneven road surfaces, some of the wheels *."attached to the rear axles may lose contact with the road surface and wherein the load carried by the vehicle is supported by only one rear axle.

The present invention aims to alleviate at least one of the above disadvantages and to provide a vehicle suspension assembly that is reliable and efficient in use.

With the foregoing in view, this invention in one aspect resides broadly in a vehicle suspension assembly suspendable from a vehicle's chassis, said vehicle suspension assembly including: 11 _r;~-lli~UV a pair of substantially parallel vehicle axles aligned substantially perpendicular to a longitudinal axis of the vehicle chassis; a pair of opposed beams that lie in respective planes which are substantially parallel to the longitudinal axis of the vehicle chassis, each beam having a midportion that is suspended from an opposite side of the vehicle chassis, a leading end portion to which the first of said axles is attached and a trailing end portion; a second pair of opposed beams that lie in respective planes that are substantially parallel to the longitudinal axis of the vehicle chassis, each beam having a mid-portion that is suspended from an opposite side of the vehicle chassis, a 10 leading end portion to which the second of said axles is attached and a trailing end portion; said trailing end portion of each of said first pair of beams being connected to said leading portion of an adjacent one of said second pair of beams by connecting means that inhibits or limits the transmission of the vertical component of forces acting on each of said trailing end portions to said adjacent leading end portions to which it is operatively connected by said connecting means.

Preferably the vehicle assembly includes a third axle which is substantially parallel to each of the aforementioned axles. For example, the third axle may be operatively connected to the trailing end portions of each of the second pair of beams.

The beams may include a rigid beam or a flexible beam. For example each beam may comprise a leaf spring.

The connection means may include a beam having a first end portion that is connected to a portion of the vehicle chassis located behind the first axle and a second or opposing end portion that is connected to said first axle. The beam may be 3 an unbroken beam, such as a leaf spring, or a broken beam, such as a plurality of pivotally connected linkage members.

The connecting beam or one of the aforementioned linkage members may be connected to the leading end portion of an. adjacent one of the second pair of beams by dampening means that may include a spring or a "spring like" member. For example, in one embodiment the spring may include a block constructed from an elastic material that can be compressed and stretched, such as a synthetic rubber material. Alternatively the "spring like" member may include a hydraulic ram.

Preferably the dampening means includes a coiled spring that is wound conically o: 10 whereby when compressed, selected segments of the coiled spring are surrounded by other segments.

In another aspect, this invention relates to a vehicle suspension assembly suspendable from a vehicle's chassis, said vehicle suspension assembly including: three substantially parallel axles that are suspended from the vehicle chassis 15 by two pairs of opposing beams.

The beams may include a rigid beam or a flexible beam, such as a leaf spring.

0*.0 In order that this invention may be more easily understood and put into practical effect reference will now be made to the accompanying drawing which illustrates a preferred embodiment of the invention.

Figure 1 is a side view of a vehicle suspension assembly constructed in accordance with the present invention.

Figure 1 shows the rear end 10 of a vehicle chassis that includes two opposing longitudinal chassis members 11 which are substantially parallel to a longitudinal axis of the vehicle's chassis.

The vehicle also includes three axles, 12, 13 and 14 that are aligned substantially perpendicular to the aforementioned longitudinal axis of the vehicle's chassis.

The vehicle's suspension assembly supporting the three axles 12, 13 and 14 includes a pair of opposed beams, or leaf springs 15 that lie in respective planes which are substantially parallel to the longitudinal axis of the vehicle's chassis. Each leaf spring 15 includes a mid-portion 16 that is both suspended from and connected to an adjacent chassis member 11 by a spring housing 17.

Opposing end portions of the leading or first axle 12 are both suspended from 10 and connected to the leading end portion 18 of an adjacent leaf spring The vehicle suspension assembly also includes a second pair of opposed beams, or leaf springs 19 that lie in respective planes which are substantially parallel to the longitudinal axis of the vehicle's chassis. Each leaf spring 19 includes a midportion 20a that is both suspended from and attached to an adjacent chassis 15 member 11 by a spring housing Opposing end portions of the second or intermediate axle 13 are both suspended from and connected to the leading end portion 21 of an adjacent leaf spring 19.

Opposing end portions of the third or trailing axle 14 are both suspended from and connected to the trailing end portion 22 of an adjacent leaf spring 19.

The trailing end portion 23 of each leaf spring 15 is connected by respective connecting means 24 to the leading end portion 21 of an adjacent leaf spring 19, the connecting means being adapted to inhibit or limit the transmission of the vertical component of forces acting on the trailing end portion 23 to said leading end portion 21. The connecting means includes a broken beam consisting of two linkage members 25 and 26 that are pivotally connected together at 27. The opposite end portion 28 of linkage member 25 is connected to the trailing end portion 23 of an adjacent leaf spring 15. The opposite end portion 29 of the linkage member 26 is pivotally connected to the spring housing 20 at The leading end portion 21 of each leaf spring 19 is connected to the midportion 31 of an adjacent linkage member 26 by a coiled spring 32 that is capable of being compressed as well as stretched.

In use, when the wheels 33 mounted on the leading axle 12 strike a protrusion in the road surface, the leading end portion 18 of each leaf spring 15 is displaced 10 upwardly in the direction of arrow 34 resulting in a corresponding downward movement of the trailing end portion 23 as indicated by arrow 35. This in turn causes a generally downward movement of the free end 36 of the linkage member 26 and the compression of spring 32. Preferably very little of the vertical component of the force applied to coiled spring 32 is transmitted to the leading end portion 21 of the leaf spring 19 to which it is attached and whereby the wheels 37 mounted on the opposing ends of the trailing axle 14 shall remain in contact with the road surface o:o•° Similarly, should the wheels 33 strike a depression in the road surface, the leading end portion 18 of each leaf spring 15 is displaced downwardly in the opposite direction to arrow 34 resulting in a corresponding upward movement of the trailing end portion 23 in the opposite direction to arrow 35. This in turn causes a generally upward movement of the free end 36 of the linkage member 26 and the stretching of the coiled spring 32. Preferably very little of the vertical component of the force applied to the coiled spring 32 is transmitted to the leading end portion 21 of the leaf spring 19 to which it is attached and whereby the wheels 38 mounted on the 6 opposing ends of the intermediate axle 13 shall remain in contact with the road surface It will of course be realised that the above has been given only by way of illustrative example of the present invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein defined in the appended claims.

Claims

1. A vehicle suspension assembly suspendable from a vehicle's chassis, said vehicle suspension assembly including: a pair of substantially parallel vehicle axles aligned substantially perpendicular to a longitudinal axis of the vehicle chassis; a pair of opposed beams that lie in respective planes which are substantially parallel to the longitudinal axis of the vehicle chassis, each beam having a mid- portion that is suspended from an opposite side of the vehicle chassis, a leading end S: 10 portion to which the first of said axles is attached and a trailing end portion; a second pair of opposed beams that lie in respective planes that are substantially parallel to the longitudinal axis of the vehicle's chassis, each beam having a mid-portion that is suspended from an opposite side of the vehicle chassis, a leading end portion to which the second of said axles is attached and a trailing end 15 portion; said trailing end portion of each of said first pair of beams being connected to said leading portion of an adjacent one of said second pair of beams by connecting means that inhibits or limits the transmission of the vertical component of forces acting on each of said trailing end portions to said adjacent leading end portions to which it is operatively connected by said connecting means.

2. A vehicle suspension assembly substantially as hereinbefore described with referenced to the accompanying drawings. 1-4 44 8 DATED THIS FOURTH DAY OF MAY, 2000 DAVTD BAILEY 4 *SS S~