SE541150C2

SE541150C2 - Air suspension device and a vehicle comprising such an air suspension device

Info

Publication number: SE541150C2
Application number: SE1750831A
Authority: SE
Inventors: Daniel Korhonen; David Karlsson; Jukka Hyttinen; Mika Kyllönen
Original assignee: Scania Cv Ab
Priority date: 2017-06-28
Filing date: 2017-06-28
Publication date: 2019-04-16
Also published as: SE1750831A1; DE102018004916A1

Abstract

The invention relates to an air suspension device (10) for a vehicle (1), the air suspension device (10) comprising: an air bellow (12); and an elongated bracket member (16) attached to the air bellow (12), wherein the bracket member (16) is adapted to be attached to a rigid axle beam (20) of the vehicle (1). The bracket member (16) is adapted to be pivotally attached to the axle beam (20), wherein the air suspension device (10) further comprises an arm (18) attached to the bracket member (16), wherein the arm (18) is adapted to be attached to a vehicle frame (22) to restrict the pivoting movement of the bracket member (16).The invention relates also relates to a vehicle (1) comprising such an air suspension device (10).

Description

Air suspension device and a vehicle comprising such an air suspension device TECHNICAL FIELD The present invention relates to an air suspension device fora vehicle and a vehicle comprising such an air suspension device. More specifically, the present invention relates to an air suspension device suitable for low-floor vehicles.

BACKGROUND Today it is common that vehicles comprise air suspension devices in order to achieve a smooth driving experience. Such air suspension devices may be called air bags, air bellows or air springs and typically comprise an air bellow and a bracket attached to the air bellow and the axle. The air suspension device may also comprise a piston arranged to move inside the air bellow, whereby the bracket is attached to the air bellow via the pistion. The configuration of the air suspension device may vary depending on whether the air suspension device is part of a dependent suspension system or an independent suspension system. An independent suspension system means that each wheel on the same axle can move vertically independently of the others. A dependent suspension system on the contrary means that all wheels on the same axle are rigidly connected, whereby movement of a wheel on one side of the axle will affect the wheel on the other side of the axle. Vehicles having a dependent suspension system typically comprise rigid axle beams, also called beam axles. Thus, with rigid axle beams the air suspension devices on both sides of the axle will be affected during axle roll movement.

The position of the air suspension devices may be determined partly by surrounding components and is therefore not always kinematically optimized. Depending on the length of the air suspension bracket and thus depending on the distance between the piston/air bellow and the axle, roll movement of a rigid axle beam may also cause a lateral movement of the part connected to the air bellow. This way, the air bellow may be exposed to shear forces which reduce the lifetime of the air bellow, and thus the lifetime of the air suspension device. This is specifically a problem in vehicles having low floors. In such low-floor vehicles, the air suspension device is typically arranged next to the chassis and the air bellow is arranged high above the axle due to lack of space. One way of avoiding the problem with lateral movement of the air suspension device during axle roll movement is of course to use independent suspension as described above.

SUMMARY OF THE INVENTION Despite known solutions in the field, there is still a need to develop an air suspension device for a rigid axle, which reduces the shear forces acting on the air suspension device during axle roll movement and thereby has a prolonged lifetime.

An object of the present invention is therefore to propose a novel and advantageous air suspension device, which reduces the shear forces acting on the air suspension device during axle roll movement. An object of the present invention is thus to achieve an air suspension device for a rigid axle beam, which has a prolonged lifetime.

Another object of the invention is to propose a vehicle having an air suspension device which reduces the shear forces acting on the air suspension device during axle roll movement.

Some of these objects are achieved with an air suspension device and a vehicle comprising such an air suspension device according to the appended claims.

Hence, according to an aspect of the invention an air suspension device for a vehicle is provided. The air suspension device comprising: an air bellow; and an elongated bracket member attached to the air bellow, wherein the bracket member is adapted to be attached to a rigid axle beam of the vehicle. The bracket member is adapted to be pivotally attached to the axle beam, wherein the air suspension device further comprises an arm attached to the bracket member, wherein the arm is adapted to be attached to a vehicle frame to restrict the pivoting movement of the bracket member.

The air suspension device may also comprise a piston, wherein the bracket member is attached to the air bellow via the piston. As in commonly known air suspension devices the piston is adapted to move back and forth within the air bellow and thereby dampen the vertical movement of the wheels.

The present invention relates to an air suspension device for a vehicle having rigid axles, meaning that the air suspension device is adapted for rigid axle beams, also called beam axles. With rigid axles, vertical movement of a wheel on one side of the axle will affect the wheel on the other side of the axle, and the air suspension device on both sides of the axle will thereby be affected. That is, the air suspension device according to the invention is configured for use in dependent suspension systems. Normally, the bracket member connected to the air bellow is fixedly attached to the axle beam. During vertical movement of the wheels (axle roll movement) the bracket member will, due to the fixed attachment to the axle beam, move laterally relative to the air bellow. In the case where the air suspension device comprises a piston the bracket member will cause a lateral movement of the piston relative to the air bellow. The higher the position of the piston/air bellow is compared to the axle beam the larger is the lateral movement during axle roll. The lateral movement causes shear forces acting on the air bellow which may reduce the lifetime of the air suspension device. By arranging the bracket member pivotally at the axle beam, the bracket member can move in relation to the axle beam. The pivotal attachment of the bracket member, together with the arm which connects the bracket member and the vehicle frame, will maintain the bracket member in an essentially vertical position during axle roll movement. This way, the kinematics of the air suspension device is optimized, the lateral movement affecting the air bellow is reduced and the lifetime of the air suspension device is thereby increased. By vertical means a direction aligned with the direction of force of gravity.

According to an embodiment of the invention the bracket member is adapted to extend essentially perpendicularly to the longitudinal extension of the axle beam. The bracket member is suitably also adapted to extend essentially perpendicularly to the road surface on which the vehicle is operating. The bracket member may thus be adapted to extend essentially perpendicularly to the longitudinal extension of the vehicle. In other words, the bracket member is suitably adapted to extend essentially vertically.

The air suspension device may be adapted to be arranged between a vehicle frame and a wheel on the axle beam. The vehicle frame is suitably a part of the vehicle chassis. The air suspension device may be adapted to be used on a low-floor vehicle. That is, the bracket member may be configured such that the air bellow is arranged relatively high above the axle beam. The arm may thus be adapted to be attached to a vehicle frame next to the air suspension device in the horizontal direction. The arm will thereby restrict the pivotal movement of the bracket member.

According to an embodiment of the invention the arm is adapted to be attached to the vehicle frame, such that the arm extends essentially perpendicularly to a longitudinal extension of the bracket member and essentially in parallel with the axle beam. The arm is auitably adapated to be attached to the vehicle frame such that the arm extends essentially horizontally. This way, the later movement of the bracket member is minimized.

According to an embodiment of the invention the arm is pivotally attached to the bracket member. The arm may be pivotally attached to the bracket member by means of a ball joint, bushing or similar. The arm may additionally or alternatively be pivotally attached to the vehicle frame. The arm may be pivotally attached to the vehicle frame by means of a ball joint, bushing or similar. This way, the arm is moveable relative to the bracket member and/or the vehicle frame which enables the air suspension device to move with the movement of the wheel/axle while maintaining an essentially vertical position of the bracket member. The arm may be referred to as a linkage, link arm or similar.

According to an embodiment of the invention the bracket member is pivotally attached to the axle beam by means of a revolute joint. The bracket member may be pivotally attached to the axle beam by means of a hinge joint or similar.

According to an aspect of the invention a vehicle is provided, the vehicle comprising an air suspension device as disclosed herein. The vehicle thus comprises an air suspension device comprising: a bellow; and an elongated bracket member attached to the piston, wherein the bracket member is adapted to be attached to a rigid axle beam of the vehicle, wherein the air suspension device further comprises an arm attached to the bracket member, wherein the arm is adapted to be attached to a vehicle frame, and wherein the bracket member is adapted to be pivotally attached to the axle beam.

Further objects, advantages and novel features of the present invention will become apparent to one skilled in the art from the following details, and also by putting the invention into practice. Whereas the invention is described below, it should be noted that it is not confined to the specific details described. One skilled in the art having access to the teachings herein will recognise further applications, modifications and incorporations in other fields, which are within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS For fuller understanding of the present invention and its further objects and advantages, the detailed description set out below should be read in conjunction with the accompanying drawings, in which the same reference notations denote similar items in the various diagrams, and in which: Figure 1 schematically illustrates a vehicle according to an embodiment of the invention; and Figure 2 schematically illustrates an air suspension according to an embodiment of the invention; DETAILED DESCRIPTION OF THE DRAWINGS Figure 1 schematically shows a side view of a vehicle 1 according to an embodiment of the invention. The vehicle 1 comprises a propulsion unit 2, which for example may be an internal combustion engine or an electric machine. The vehicle 1 further comprises at least two axles 4 with at least one wheel 6 arranged at each end of each axle 4. The axles 4 are rigid axles, also called beam axels, which means that the at least two opposite wheels 6 on each axle 4 are rigidly connected. Each axle 4 comprises two air suspension devices 10 arranged adjacent the wheels 6. In this figure the vehicle 1 is a low-floor bus but the vehicle may be a truck, a forest machine, a mining vehicle, a construction vehicle, a rescue vehicle or similar. The vehicle 1 may alternatively be a passenger car. The vehicle 1 may be a hybrid vehicle comprising two propulsion units 2. The air suspension device 10 will be further described in Figure 2.

Figure 2 schematically illustrates an air suspension device 10 for a vehicle according to an embodiment of the invention. In this figure, the air suspension device 10 is arranged on the vehicle 1. The air suspension device 10 may be adapted to be used on a vehicle 1 as disclosed in Figure 1. The air suspension device 10 comprises: an air bellow 12; a piston 14 arranged to reciprocate inside the air bellow 12; and an elongated bracket member 16 attached to the piston 14, wherein the bracket member 16 is adapted to be attached to a rigid axle beam 20 of the vehicle 1. The rigid axle beam 20 is thus a part of a rigid axle 4 as disclosed in Figure 1. The bracket member 16 is adapted to be pivotally attached to the axle beam 20. The bracket member 16 attached to the axle beam 20 will follow vertical movements of the axle beam 20, whereby the piston 14 will move back and forth within the air bellow 12 and damping will be provided. The air suspension device 10 further comprises an arm 18 attached to the bracket member 16. The arm 18 is also adapted to be attached to a vehicle frame 22. The arm 18 is thus attached to the bracket member 16 in one end and in the other end to the vehicle frame 22. By arranging the bracket member 16 pivotally at the axle beam 20, the bracket member 16 can move in relation to the axle beam 20. The arm 18, which connects the bracket member 16 to the vehicle frame 22, restricts the pivoting movement of the bracket member 16 and will retain the bracket member 16 in an essentially vertical position also during axle roll movement. This way, the lateral movement of the piston 14 is reduced and the lifetime of the air suspension device 10 is increased. In this figure the air suspension device 10 comprises a piston 14 but it is to be understood that the invention is applicable also for air suspension devices lacking pistons, where the bracket member is directly connected to the air bellow.

The bracket member 16 may be adapted to extend essentially perpendicularly to the longitudinal extension of the axle beam 20 and essentially perpendicularly to the longitudinal extension of the vehicle 1. The bracket member 16 is attached to the axle beam 20 in one end and to the piston 14 in the other end.

The air suspension device 10 is in this embodiment arranged between a vehicle frame 22 and a wheel 6 on the axle beam 20 but it is to be understood that the air suspension device 10 may be arranged in any other way in relation to the vehicle frame 22. The arm 18 may thus be adapted to be attached to a vehicle frame 22 next to the air suspension device 10 in the horizontal direction. The arm 18 may thus be adapted to be attached to the vehicle frame 22, such that the arm 18 extends essentially perpendicularly to a longitudinal extension of the bracket member 16 and essentially in parallel with the axle beam 20.

The arm 18 may be pivotally attached to the bracket member 16 by means of first attachment means 24. The first attachment means 24 may be a ball joint, bushing or similar. The arm 18 may be pivotally attached to the vehicle frame 22 by means of second attachment means 26. The second attachment means 26 may be a ball joint, bushing or similar. The arm 18 may be made of steel, composite or similar.

The bracket member 16 may be pivotally attached to the axle beam 20 by means of third attachment means 28. The third attachment means 28 may be a revolute joint, a hinge joint or similar.

The foregoing description of the preferred embodiments of the present invention is provided for illustrative and descriptive purposes. It is not intended to be exhaustive or to restrict the invention to the variants described. Many modifications and variations will obviously be apparent to one skilled in the art. The embodiments have been chosen and described in order best to explain the principles of the invention and its practical applications and hence make it possible for specialists to understand the invention for various embodiments and with the various modifications appropriate to the intended use.

Claims

1. An air suspension device (10) for a vehicle (1), the air suspension device (10) comprising: an air bellow (12); and an elongated bracket member (16) attached to the air bellow (12), wherein the bracket member (16) is adapted to be attached to a rigid axle beam (20) of the vehicle (1), characterized in that the bracket member (16) is adapted to be pivotally attached to the axle beam (20), wherein the air suspension device (10) further comprises an arm (18) attached to the bracket member (16), wherein the arm (18) is adapted to be attached to a vehicle frame (22) to restrict the pivoting movement of the bracket member (16).

2. The air suspension device (10) according to claim 1, wherein the arm (18) is pivotally attached to the bracket member (16).

3. The air suspension device (10) according to claim 1 or 2, wherein the bracket member (16) is adapted to extend essentially perpendicularly to the longitudinal extension of the axle beam (20).

4. The air suspension device (10) according to any of the preceding claims, wherein the arm (18) is adapted to extend essentially perpendicularly to a longitudinal extension of the bracket member (16) and essentially in parallel with the axle beam (20).

5. The air suspension device (10) according to any of the preceding claims, wherein the bracket member (16) is pivotally attached to the axle beam (20) by means of a revolute joint (28).

6. The air suspension device (10) according to any of the preceding claims, wherein the arm (18) is pivotally attached to the vehicle frame (22).

7. The air suspension device (10) according to claim 6, wherein the arm (18) is pivotally attached to the vehicle frame (22) by means of a ball joint (26).

8. A vehicle (1) comprising an air suspension device (10) according to any one of claims 1-7.

9. The vehicle (1) according to claim 8, wherein the vehicle (1) is a low-floor bus.