| JP2007126005 | VEHICULAR SUSPENSION DEVICE |
| JP3489245 | SUSPENSION FOR VEHICLE |
| JP05278421 | REAR SUSPENSION OF AUTOMOBILE |
MCCORMICK, Darren, James (74 Rockfield Heights, ConnorBallymena, Antrim BT42 3GH, GB)
| Claims 1. A suspension apparatus comprising: (i) an upright suspension member for locating, in use, a vehicle's wheel and hub assembly; (ii) an upper suspension arm provided with a first distal end portion which is pivotably mounted to the upright suspension member; (iii) a lower suspension arm provided with a first distal end portion which is pivotably mounted to the upright suspension member, and an opposing second distal end portion which, in use, is pivotably mounted to a vehicle chassis member; and (iv) a spring member retained, in use, between the second distal end portion of the upper suspension arm and an underlying vehicle chassis member; wherein the upper suspension arm is pivotably mountable to a vehicle chassis member about a pivot point located between its opposing first and second distal end portions thus serving, in use, to transfer a vehicle wheel's vertical acceleration forces from the first distal end portion of the upper suspension arm to the spring member. 2. A suspension apparatus as claimed in claim 1 wherein the spring member is an air spring. 3. A suspension apparatus as claimed in claim 1 or claim 2 wherein bushes and/or bearings are provided on the upper and lower suspension arms to facilitate their pivotable mounting to vehicle chassis members. 4. A suspension apparatus as claimed in any one of the preceding claims wherein ball joints and/or bushes and/or bearings are provided on the upper and lower suspension arms to facilitate pivotable mounting to the upright suspension member. 5. A suspension apparatus as claimed in any one of the preceding claims wherein the pivot point located between the opposing first and second distal end portions of the upper suspension arm is positioned midway between the distal end portions. 6. A suspension apparatus as claimed in any one of the preceding claims wherein the suspension apparatus is a double-wishbone suspension apparatus wherein the upper and lower suspension arms are in the form of wishbone arms. 7. A suspension apparatus as claimed in any one of the preceding claims wherein the suspension apparatus is an independent front suspension apparatus for a passenger service vehicle. 8. A passenger service vehicle comprising floor chassis members supported on vehicle wheel and hub assembly by a suspension apparatus as claimed in any one of claims 1 to 6. 9. A passenger service vehicle as claimed in claim 8 wherein the pivot point between the opposing first and second distal end portions of the upper suspension arm is connected to a floor chassis member at a position whereby, during a vehicle wheel's vertical movement, all parts of the suspension apparatus are maintained below a horizontal plane coincident with an uppermost part of the floor chassis members. 10. A suspension apparatus substantially as defined herein with reference to the accompanying drawings. |
The present invention relates to a suspension apparatus and particularly, but not exclusively, to a low-profile suspension apparatus for use on the front axle of passenger service vehicles such as "midi" buses.
In view of established legislative requirements, it is well known to provide urban passenger service vehicles with low-floor arrangements to ease the boarding and alighting of passengers with reduced mobility such as the disabled or infirm. Many low-floor passenger service vehicles employ air springs which can facilitate "kneeling" of independent front suspension systems to further assist with, for example, front door wheelchair access.
However, a particular problem arises in smaller "midi" type passenger service vehicles wherein the driver's cab is sited substantially over the front axle. Such positioning is desirable insofar as it maximises the available space behind the driver's cab and hence the passenger carrying capacity of the vehicle. However, an undesirable consequence of this arrangement is that the driver's seating position must be raised by an amount sufficient to accommodate the underlying conventional suspension system consisting of bulky air springs which extend above a double- wishbone structure. In particular, the resulting heightened driver's position is incompatible with low-floor arrangements from a driver-passenger interface perspective since it is desirable to keep the driver's position as low as possible. Accordingly, there exists a conflict in satisfying the competing
requirements of maintaining a lowered ergonomic driver seating position whilst maximising vehicle capacity by positioning the driver's cab forwardly over the front axle.
According to a first aspect of the present invention, there is provided a suspension apparatus at least comprising:
(i) an upright suspension member for locating, in use, a vehicle's wheel and hub assembly;
(ii) an upper suspension arm provided with a first distal end portion which is pivotably mounted to the upright suspension member;
(iii) a lower suspension arm provided with a first distal end portion which is pivotably mounted to the upright suspension member, and an opposing second distal end portion which, in use, is pivotably mounted to a vehicle chassis member; and
(iv) a spring member retained, in use, between the second distal end portion of the upper suspension arm and an underlying vehicle chassis member; wherein the upper suspension arm is pivotably mountable to a vehicle chassis member about a pivot point located between its opposing first and second distal end portions thus serving, in use, to transfer a vehicle wheel's vertical acceleration forces from the first distal end portion of the upper suspension arm to the spring member.
Optionally, the spring member is an air spring. Optionally, bushes and/or bearings are provided on the upper and lower suspension arms to facilitate their pivotable mounting to vehicle chassis members. Optionally, ball joints and/or bushes and/or bearings are provided on the upper and lower suspension arms to facilitate pivotable mounting to the upright suspension member.
Optionally, the pivot point located between the opposing first and second distal end portions of the upper suspension arm is positioned midway between the distal end portions.
Optionally, the suspension apparatus is a double-wishbone suspension apparatus wherein the upper and lower suspension arms are in the form of wishbone arms.
Optionally, the suspension apparatus is an independent front suspension apparatus for passenger service vehicles. According to a second aspect of the present invention, there is provided a passenger service vehicle comprising floor chassis members supported on vehicle wheel and hub assembly by a suspension apparatus according to the first aspect. Optionally, the pivot point between the opposing first and second distal end portions of the upper suspension arm is connected to a floor chassis member at a position whereby, during a vehicle wheel's vertical movement, all parts of the suspension apparatus are maintained below a horizontal plane coincident with an uppermost part of the floor chassis members. An embodiment of the present invention is described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a double-wishbone suspension apparatus connected to a vehicle wheel and hub assembly; and
Fig. 2 is a perspective view corresponding to Fig. 1 also showing the connection of the suspension apparatus to a vehicle chassis via air springs.
Fig. 1 shows a double-wishbone suspension apparatus having a pair of upright suspension members 10 to which are attached an upper wishbone arm 12 and a lower wishbone arm 14 respectively. Each upright suspension member 10 locates a vehicle wheel/hub assembly 16 in a conventional manner. Each upper and lower wishbone arm 12, 14 is pivotally connected, by means of suitable bushes or bearings, to upper and lower portions of its upright suspension member 10 via respective first distal end portions 12a, 14a.
An opposing second distal end 12b of each upper wishbone arm 12 is provided with a circular plate 12c to facilitate its connection to the upper surface of an air spring (see Fig. 2). Each upper wishbone arm 12 is additionally provided with a pivot point 12d positioned substantially midway between its respective first and second distal end portions 12a, 12b to facilitate its pivotable connection, by means of suitable bushes or bearings, to a vehicle chassis (see Fig. 2). Similarly, opposing second distal ends 14b of each lower wishbone arm 14 are provided with suitable bushes or bearings to facilitate their pivotable connection to a vehicle chassis (see Fig. 2). Fig. 2 shows the double-wishbone suspension apparatus of Fig. 1 when connected to a vehicle chassis 20. The vehicle chassis 20 is provided with upper and lower chassis members 22, 24 which are connected together to define a three-dimensional box-like hollow structure having a height which is generally similar to that of the upright suspension member 10. Air springs 26 are positioned within the volume defined by the upper and lower chassis members 22, 24. The upper surface of each air spring 26 is attached to the circular plate 12c at the second distal end 12b of its corresponding upper wishbone arm 12. The lower surface of each air spring 26 is attached to the lower chassis member 24. A damper 28 is connected between an upper chassis member 22 and a lower portion of each upright suspension member 10.
The upper wishbone arms 12 are each connected to an upper chassis member 22 of the vehicle chassis 20 via the pivot point 12d between their first and second distal ends 12a, 12b. The lower wishbone arms 14 are each connected to a lower chassis member 24 of the vehicle chassis 20 via the pivotal connection at their second distal end 14b. In use, the vertical acceleration forces experienced by the wheel/hub assembly 16 are transferred through the upright suspension member 10 to the first distal ends 12a, 14a of the upper and lower wishbone arms 12, 14. The position of pivot point 2d on each upper wishbone arm 12 acts as a counterbalance to transfer such forces to the air spring 26 attached to the second distal end 12b of each upper wishbone arm 12. For example, vertical movement of the wheel/hub assembly 16 in the direction of arrow A in Fig. 2 causes the upright suspension member A to move upwards. The vertical (upward) force acting on the first distal end 12a of the upper wishbone arm 2 causes it to rotate around pivot point 12d such that the circular plate 2c at its second opposing distal end 12b is forced downwards against the air spring 26 which absorbs the vertical acceleration force and minimises any transfer to the underlying chassis member 24. The particular arrangement of the components described above results in a more compact apparatus thus achieving a low profile front suspension without compromising on suspension travel or roll stabilities found in conventional independent suspension systems. When used in "midi" type passenger service vehicles, such a suspension arrangement allows the driver to be positioned over the front axle to maximise passenger spacing and interaction whilst obviating the need to raise the driver's seating position.
Modifications and improvements may be made to the foregoing without departing from the scope of the present invention.
Next Patent: WIRELESS COMMUNICATION SYSTEM WITH WIRELESS BACKHAUL CONNECTION