VEHICLE SUSPENSION COMPRISING A LEAF SPRING ASSEMBLY

Abstract

A vehicle suspension arrangement includes a leaf spring assembly with at least two leaf springs which are arranged, during use in a vehicle, with a longitudinal extension generally coinciding with the longitudinal extension of said vehicle; the suspension arrangement includes a spring clamping unit connecting the leaf springs to an axle in the vehicle; and wherein each of the leaf springs includes end sections which are configured to be fastened in a vehicle chassis. Furthermore, the spring clamping unit includes a spacer component which is configured for separating the leaf springs in a vertical or horizontal direction.

Claims

1. Vehicle suspension arrangement comprising a leaf spring assembly with at least two leaf springs which are arranged, during use in a vehicle, with a longitudinal extension generally coinciding with the longitudinal extension of the vehicle; the suspension arrangement comprising a spring clamping unit connecting the leaf springs to an axle in the vehicle; and wherein each of the leaf springs comprises front and rear end sections which are configured to be fastened in a vehicle chassis; wherein the spring clamping unit comprises a spacer component which is configured for separating the leaf springs in a vertical or horizontal direction, wherein the vehicle suspension arrangement further comprises at least one upper leaf spring and at least one lower leaf spring, the upper and lower leaf springs being mounted vertically spaced apart, wherein the upper leaf spring is arranged in a reverse manner, as regarded with reference to a horizontal plane, with respect to the lower leaf spring, wherein the at least one upper leaf spring and at least one lower leaf spring are connected to the same common anchoring point in the front end section and the rear end section, respectively.

2. Vehicle suspension arrangement according to claim 1, wherein the the spacer component is constituted by a generally homogenuous material through which the leaf springs extend whereby the spacer component separate the leaf springs.

3. Vehicle suspension arrangement according to claim 1, wherein each leaf spring comprises a rear spring eye and a front spring eye for fastening the leaf spring in the chassis, whereby the rear spring eyes are fastened in a common point and the front spring eyes (20) are fastened in a farther common point.

4. Vehicle suspension arrangement according to claim 1, wherein it comprises three leaf springs of which two leaf springs are arranged horizontally spaced apart and wherein the third leaf spring is arranged vertically spaced apart from the two remaining leaf springs, the third leaf spring furthermore being arranged in a reverse manner, as regarded with reference to a horizontal plane, with respect to the remaining leaf springs.

5. Vehicle suspension arrangement according to claim 1, wherein all leaf springs extend along a top side of the axle.

6. Vehicle suspension arrangement according to claim 1, wherein at least one leaf spring extends across a top side of the axle and at least one leaf spring extend underneath a bottom side of the axle.

7. Vehicle suspension arrangement according to claim 1, wherein the leaf springs are constituted by parabolic springs,

8. Vehicle comprising a suspension arrangement according to claim 1.

9. (canceled)

Description

BRIEF DESCRIPTION OF DRAWINGS

[0022] The invention will now be described with reference to an embodiment and with reference to the appended drawings, wherein:

[0023] FIG. 1 shows a side view of a vehicle in which the invention can be used;

[0024] FIG. 2 shows a perspective view of a vehicle suspension arrangement according to an embodiment;

[0025] FIG. 3 is a cross-sectional view of the arrangement according to an embodiment;

[0026] FIGS. 4a and 4b are perspective views of a leaf spring assembly according to an embodiment; and

[0027] FIG. 5 is a further cross-sectional view of a second embodiment.

DETAILED DESCRIPTION

[0028] Different aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. The arrangement disclosed below can, however, be realized in many different forms and should not he construed as being limited to the aspects set forth herein.

[0029] With reference initially to FIG. 1, there is shown a side view of a commercial vehicle 1 in the form of a tractor unit. The vehicle 1 comprises a chassis 2 and a driver's cab 3 mounted on the chassis 2. Underneath the driver's cab 3 is an internal combustion engine 4 which drives a pair of drive wheels 6 by way of a drive train 5 which comprises a clutch and a transmission (not shown).

[0030] The internal combustion engine 4 is associated with an exhaust gas system 7 which is arranged for discharging exhaust gas into the atmosphere. The driver's cab 3 is also supported by a pair of steerable front wheels 8. The wheels 8 are mounted on a front axle 9 which is attached to a vehicle suspension arrangement 10. Furthermore, the suspension arrangement 10 comprises two leaf spring assemblies, of which only one leaf spring assembly 11 is visible in FIG. 1. The leaf spring assembly 11 is supported by a front spring attachment 12 and a rear spring attachment 13 so as to be connected to the frame 2. As shown in FIG. 1, the leaf spring assembly 11 is also connected to the frame 2 by an air spring or bellows 14.

[0031] The suspension arrangement 10 will now described in greater detail with reference to FIG. 2 together with FIG. 3. Initially, it should be noted that FIG. 2 is a perspective view showing a first and a second leaf spring assembly 11, 11′, of which the first leaf spring assembly 11 corresponds to that shown in FIG. 1. The following description of the first leaf spring assembly 11 applies to the second leaf spring assembly 11′ too.

[0032] According to an embodiment, the leaf spring assembly 11 is formed by three parabolic leaf springs which extend generally parallel to each other, along the longitudinal direction of the vehicle, and which also extend across the front axle 9. It should be noted that FIG. 1 shows the leaf spring assembly 11 as a single package, although it is composed of three leaf springs, as will be described in greater detail below with reference to FIGS. 3, 4a and 4b.

[0033] As indicated in FIG. 2, the leaf spring assembly 11 is clamped to the front axle 9 along a section 15 of the leaf spring assembly 11 which extends above the front axle 9. More precisely, the leaf spring assembly 11 is clamped to the front axle 9 by means of a U-bolt clamp arrangement 16 and a spring centre bolt 17.

[0034] The spring centre bolt 17 is also shown in FIG. 3, which is a cross-sectional view of the first spring assembly 11 as regarded in the longitudinal direction of the vehicle towards the axle 9. FIG. 3 shows a cross-sectional view of the three parabolic leaf springs 11a, 11b, 11c which are shown together as a single leaf spring assembly 11 in FIG. 2. Furthermore, the spring centre bolt 17 is arranged through the first leaf spring 11a and is anchored securely in the axle 9. According to the embodiment, the three leaf springs 11a, 11b, 11c are configured so that they are maintained separated in a manner wherein the second leaf spring 11b and third leaf spring 11c

[0035] are separated in a horizontal direction, and the first leaf spring 11a is arranged to be separated from the second and third leaf springs 11b, 11c in a vertical direction. This is accomplished by means of a spacer component 18 which is arranged along the section 15 of the leaf spring assembly 11 (see also FIG. 2). The spacer component 18 is formed by a generally homogenuous material through which the leaf springs 11a, 11b, 11c extend. In this manner, the spacer component 18 will separate the leaf springs 11a, 11d, 11c according to a desired configuration. According to an embodiment, the spacer component 18 is constituted by steel or aluminium and is configured so as to retain the leaf springs 11a, 11b, 11c in their fixed positions.

[0036] According to the embodiment, all three leaf springs 11a, 11b, 11c are constituted by parabolic leaf springs. With reference to FIGS. 4a and 4b, there is shown a simplified perspective view of the leaf spring assembly 11 in a disassembled and assembled manner, respectively. FIG. 4a shows—as also explained above—that the first leaf spring 11a is separated vertically from the second and third leaf springs 11b, 11c, and that the second and third leaf springs 11b, 11c are separated in a horizontal direction from each other.

[0037] Furthermore, the first leaf spring 11a is arranged in a mirrored, i.e. reverse, manner (as regarded with reference to a horizontal plane) as compared to the second and third leaf springs 11b, 11c. This means that the parabolic curve which is defined by the first leaf spring 11a is reversed as compared with the parabolic curves defines by the second and third leaf springs 11b, 11c. In this manner, the wind-up stiffness will be increased.

[0038] In summary, the leaf spring assembly 11 comprises at least two, but preferably three leaf springs 11a, 11b, 11c which are arranged, during use in the vehicle 1, with a longitudinal extension which generally coincides with the longitudinal extension of the vehicle. In the area 15 of the assembly 11 which is clamped to the front axle 9, the three leaf springs 11a, 11b, 11c are kept separated in a vertical and horizontal direction as shown in FIG. 3 by means of the spacer component 18.

[0039] The leaf spring assembly 11 is attached to the axle 9 by means of a spring clamping unit which can he said to be constituted by the spacer component 18 together with the U-bolt clamp arrangement 16 and the spring centre bolt 17.

[0040] Furthermore, as indicated in FIG. 4b (and also as shown in FIG. 2), the front and rear end sections of each loaf spring 11a, 11b, 11c, respectively, are anchored in a common position. More precisely, and with reference to FIG 2, it is noted that the leaf spring assembly 11 has a front end section 19 which defines a front spring eye 20 which is attached to the front spring attachment 12 via a spring shackle connection 21. Also, the leaf spring assembly 11 has a rear end section 22 which defines a rear spring eye 23 which is attached to the rear spring attachment 13. This means that all three leaf springs 11a, 11b, 11c (see FIG. 4b) are connected to the same common anchoring point in the front spring attachment 12 and the rear spring attachment 13, respectively. As indicated with reference to FIG. 1, the front spring attachment 12 and the rear spring attachment 13 are attached to the chassis of the vehicle.

[0041] Each one of the leaf springs 11a, 11b, 11c can be produced with a width which is considerably less that the total width of the leaf spring assembly 11. This reduction in width makes it possible to manufacture the leaf spring assembly 11 with a greatly reduced weight, as compared with prior art assemblies, while still maintaining a required vertical stiffness of the assembly 11. Also, since each leaf spring 11a, 11b, 11c will work side by side and also be mounted to the same connection point in the front and rear end of the assembly 11, the side stiffness will also be maintained. Also, the leaf springs 11a, 11b, 11c according to the embodiment will be used more effectively for vertical torsional and brake wind-up stiffness.

[0042] Generally, the leaf spring assembly may comprise at least one upper leaf spring and at least one lower leaf spring, wherein the upper and lower leaf springs are mounted vertically spaced apart and wherein the upper leaf spring is arranged in a reverse manner, as regarded with reference to a horizontal plane, with respect to the lower leaf spring.

[0043] According to an embodiment, the leaf spring assembly 11 as shown in FIGS. 2-4 comprises three leaf springs 11a, 11b, 11c of which two leaf springs 11b, 11c are arranged horizontally spaced apart and the third leaf spring 11a is arranged vertically spaced apart from the two remaining leaf springs 11b, 11c. Also, the third leaf spring 11a is furthermore arranged arranged in a reverse manner, as regarded with reference to a horizontal plane, with respect to the remaining leaf springs 11b, 11c.

[0044] In addition to advantages of the invention which relate to a weight saving of the complete leaf spring assembly 11, a more effective use of each leaf spring is provided as a result of an increased stiffness and an improved possibility of tuning the leaf spring assembly 11. In particular, internal forces can be introduced between the upper and lower leaf springs by biasing them during assembly of the complete leaf spring assembly, i.e. when the end sections of the leaf springs are mounted to the front spring eye and the rear spring eye, respectively.

[0045] As a result, the wind-up stiffness increases by the force distribution between the two lower leaf springs and the upper leaf spring. Furthermore, an increased torsional stiffness (i.e. about a rotational axis defined along the leaf spring assembly) is obtained due to the spring steel being placed further apart and also by letting the upper leaf spring take a torsional load directly in its spring eye. Finally, the typical kinematic behaviour on the upper leaf spring and the lower leaf springs could be tuned so that the position of the so-called “Ross point” (i.e. the rotation centre of a spring) will give a neutral effect on the vertical stiffness or give a progressive characteristic to the vertical stiffness and the wind-up stiffness of the leaf spring assembly.

[0046] As shown in FIG. 3, the leaf springs 11a, 11b, 11c are arranged so that they all extend along a top side of the axle 9. However, with reference to FIG. 5, there is shown an alternative embodiment in which the leaf spring assembly 11′ is disposed in an alternative manner with respect to the axle 9. More precisely, as shown in FIG, 5, two leaf springs 11a′ and 11b′ extend above the top side of the axle 9 whereas a third leaf spring 11c′ extend underneath the bottom side of the axle 9.

[0047] As previously described also with reference to FIG. 3, the embodiment according to FIG. 5 is based on the principle that one of the leaf springs, i.e. the third leaf spring 11c′, is mounted vertically spaced apart from the first and second leaf springs 11a′, 11b′, wherein the first and second leaf springs 11a′, 11b′ are also horizontally spaced apart. To this end, the embodiment shown in FIG. 5 comprises a spacer component 18 which is configured for separating the leaf springs 11a′, 11b′, 11c) in a vertical or horizontal direction as desired. The embodiment also includes a spring centre bolt 17′, which in contrast to the embodiment, in FIG. 3 is accessed from underneath the axle 9.

[0048] Also, the lower leaf spring 11c′ is arranged in a reverse manner, as regarded with

[0049] reference to a horizontal plane, with respect to the tipper leaf springs 11b′, 11c. However, in contrast to the embodiment shown in FIG. 3, the leaf spring assembly 11″ according to FIG. 5 is based on the principle that the first and second leaf springs 11a′, 11b′ are positioned across a top side of the axle 9 and the third leaf spring 11c′ extends underneath a bottom side of the axle 9. Also, the third leaf spring 11c′ is arranged in a reverse manner, as regarded with reference to a horizontal plane, with respect to the first and second leaf springs 11a′, 11b′.

[0050] The two leaf springs 11a′, 11b′ which are mounted above the axle 9 will operate together with the third leaf spring 11c′ as reaction rods for providing an the increased wind-up stiffness in the same way as the embodiment shown in FIG. 3.

[0051] The invention is not limited to the embodiments described above, but can be varied within the scope of the subsequent claims. For example, the invention can be used for any type of vehicle having a need for suspension of wheel axles in relation to a vehicle frame. Also, various numbers and configurations of leaf springs can be used within the scope of the claims.