Axle suspension for rigid axles of vehicles

Abstract

An axle suspension for rigid axles of vehicles, especially air-cushioned utility vehicles, with: a twistable four-point connecting rod (4), which is connected above the said vehicle axle (3) to the said vehicle axle (3). The twistable four-point connecting rod (4) is connected to the vehicle body (1, 2), on the other hand, via two said joints (5, 6, 7, 8) each, which are arranged at spaced locations from one another in the longitudinal direction of the vehicle. At least one spring assembly unit (19, 20) per vehicle side is located for springing between the said vehicle axle (3) and the said vehicle body (1, 2). A axle strut (21) for axle guiding, extends approximately in the middle of the vehicle in the longitudinal direction of the vehicle and connects the said vehicle axle (3) to the said vehicle body (1, 2) in a vertically movable manner.

Description

[0001] The present invention pertains to an axle suspension for rigid axles of vehicles, especially of air-cushioned utility vehicles.

[0002] Axle suspensions that contain a four-point connecting rod have been known, e.g., from DE 195 21 874 A1. The design embodiment of such axle suspensions is, in principle, simple, compact and cost-saving and has proved to be definitely successful in practice. However, this axle suspension, like other designs known from the state of the art, has the drawback that numerous components are necessary for axle guiding, which requires an increased assembly effort and also adversely affects the overall weight of the vehicle. Furthermore, prior-art axle suspensions are sometimes kinematically redundant. This in turn leads to an undefined course of kinematic processes within the axle construction in certain situations, which has an adverse effect on the coordination of the chassis or the chassis dynamics in the vertical and lateral directions under certain circumstances.

[0003] The technical object of the present invention is to improve an axle suspension such that the kinematic conditions are improved in order to optimize the dynamics of the vehicle movement. Moreover, the number of the individual components shall be further reduced.

[0004] This object is accomplished by the features of patent claim 1. Thus, an axle suspension according to the present invention comprises a twistable four-point connecting rod, which is arranged above the vehicle axle and is connected to the vehicle axle, on the one hand, and to the vehicle body, on the other hand, via two joints located at spaced locations from one another in the transverse direction of the vehicle.

[0005] In addition, at least one spring assembly unit is arranged between the vehicle axle and the vehicle body on each side of the vehicle.

[0006] The fact that only one axle strut, which extends in the longitudinal direction approximately in the middle of the vehicle and connects the vehicle axle to the vehicle body in a vertically movable manner, is used, can be considered to be the peculiar feature of such an axle suspension. The axle strut is arranged on the side of the vehicle axle located opposite the four-point connecting rod. The mounting of the four-point connecting rod and the axle strut in the reverse arrangement is, of course, within the scope of the present invention.

[0007] The kinematic conditions of the axle suspension are simplified and optimized by such a design. The number of components decreases considerably, so that the axle structure as a whole is less expensive than designs known hitherto.

[0008] Special embodiments of the subject of the present invention also appear from the features of the subclaims.

[0009] Thus, the spring assembly units or the shock absorbers are mounted according to the present invention on longitudinal beams, which in turn have a connection to the vehicle axle, so that there is an indirect connection between the vehicle axle and the vehicle body. It has proved to be particularly advantageous for each longitudinal beam to have at least one mount for the spring assembly units. The longitudinal beams are now arranged extending on each side of the vehicle approximately in the longitudinal direction of the vehicle and may accommodate one or more spring assembly units as well as also shock absorbers if necessary. For mounting the spring assembly units and the shock absorbers, the mounts may be designed as joints, and ball-and-socket joints may also be used for this purpose according to a special embodiment of the present invention. The said ball-and-socket joints have the advantage of ensuring an easily movable mounting of the corresponding assembly units, so that the pneumatic spring bellows are loaded to an extremely low extent only, e.g., in the case of the use of pneumatic springs.

[0010] The components of the vehicle body include according to the present invention at least two parallel longitudinal frames, which are connected to one another by crossbeams located at spaced locations from one another approximately in the transverse direction of the vehicle.

[0011] The axle strut for axle guiding, which extends in the longitudinal direction of the vehicle approximately in the middle of the vehicle and connects the vehicle axle to the vehicle body in a vertically movable manner, may be connected to one of the crossbeams by means of a carrier bracket in another embodiment of the present invention. Quite generally, a carrier bracket is defined as a mounting device, which accommodates a molecular joint of the axle strut, on the one hand, and is fixed to the vehicle body, on the other hand. The axle strut preferably has a molecular joint at each of its ends.

[0012] To achieve optimal springing of the vehicle axle, the spring assembly unit may be arranged in front of or behind the vehicle axle or in front or and behind the vehicle axle in an axle suspension according to the present invention.

[0013] Exemplary embodiments of the subject of the present invention will be explained in greater detail below on the basis of the drawings attached. In the drawings,

[0014] FIG. 1 shows a perspective view of an exemplary embodiment of the axle suspension according to the present invention as viewed obliquely from the front, i.e., opposite the direction of travel of the vehicle,

[0015] FIG. 2 shows a perspective view as viewed obliquely from the rear, i.e., in the direction of travel of the vehicle,

[0016] FIG. 3 shows a side view of the axle suspension according to the present invention without the vehicle wheel that is the right-hand wheel in the direction of travel,

[0017] FIG. 4 shows a sectional view of a molecular joint used for the axle suspension according to the present invention, and

[0018] FIG. 5 shows a top view of an axle suspension according to the present invention.

[0019] FIGS. 1 through 3 show the axle suspension according to the present invention on a utility vehicle chassis, not shown here, which is provided with longitudinal frames 1a, 1b. The longitudinal frames 1a and 1b are arranged at laterally spaced locations from one another and are firmly connected to one another by the crossbeams 2a, 2b. The longitudinal frames 1a, 1b and the crossbeams 2a, 2b are parts of the vehicle body 1, 2. The vehicle axle 3, which is connected to the longitudinal frames 1a, 1b and to one of the crossbeams 2b via a four-point connecting rod 4, is located under the longitudinal frames 1a and 1b. Furthermore, the vehicle wheels 15 and 16 are fastened to the vehicle axle 3. The four-point connecting rod 4 has a total of four joints 5, 6, 7 and 8, with two joints 6, 8 each being fastened, as was described above, to the vehicle frame and two joints 5, 7 to the vehicle axle. The joints fastened to the vehicle axle and to the vehicle frame are arranged at spaced locations from one another in the transverse direction of the vehicle and are designed as molecular joints.

[0020] A molecular joint is, in principle, a joint as it is shown as an example as a ball-and-socket joint in FIG. 4. The molecular joint comprises here an inner joint ball 30, a housing 32 surrounding the joint ball as well as an elastomer 31 arranged between the joint ball 30 and the housing 32. In the exemplary embodiment according to FIG. 4, the joint ball 30 has a two-part design, consisting of an inner, metallic joint axis 33 and an outer ball 34 made in one piece with it from an elastomer. Other embodiments of a molecular joint may be a joint ball 30 made entirely of metal or have a cylindrical inner part instead of a ball. Such molecular joints can be correspondingly adapted to the loads acting on the joint by selecting the elastomer arranged between the joint ball 30 and the housing 32. In addition, recesses, which affect the characteristics of the joint in a specific manner, may be provided at least in some areas within the elastomer and/or the housing or on the inner part of the joint. For example, molecular joints may have a lower damping in one direction and a correspondingly greater damping in at least one direction that is offset in relation to that direction.

[0021] The views in FIGS. 1 through 3 also show that the vehicle axle 3 has a connection to a crossbeam 2b, which is formed by an axle strut 21, which is in turn mounted in a carrier bracket 10 on one side. This axle strut contains one molecular joint 13, 14 on each side, the molecular joint 13 being articulated under the vehicle axle 3 and the molecular joint 14 being accommodated in the carrier bracket 10. The molecular joints 5, 6, 7, 8, 13, and 14 have, in principle, the above-described design and make it possible to absorb both longitudinal as well as vertical forces and angulations (cardanics), which are caused by the movements of the vehicle axle 3. Redundancy of the kinematic degrees of freedom is prevented by the use of the molecular joints, so that a more optimal forward coordination can be brought about in terms of the dynamics of the chassis in the vertical and lateral directions.

[0022] A longitudinal beam 11 and 12 each is fastened to the vehicle axle 3 on each side of the vehicle for the indirect connection of the vehicle axle to the vehicle body 1, 2. In the embodiment being shown, these longitudinal beams 11, 12 establish the said connection to the vehicle body 1, 2 via a spring assembly unit 19, 20 each or a shock absorber 35, 36 each.

[0023] Respective mounts 17a, 17b and 18a, 18b are present on the longitudinal beams 11 and 12 for mounting the spring assembly units 19, 20 and the shock absorbers 35, 36, respectively.

[0024] This leads to a reduction in the number of the components usually used in prior-art axle designs and thus reduces the amount of parts to be stocked and the assembly times for the axle design according to the present invention.

[0025] The top view of an exemplary embodiment of the axle design according to the present invention in FIG. 5 shows the position of the four-point connecting rod 4 as well as its articulation points on the body and on the vehicle axle 3.

[0026] It is, of course, possible to arrange three, four or more such spring elements instead of the two spring assembly units shown in an axle suspension according to the present invention and to arrange the spring assembly units 19, 20 in front of or behind the vehicle axle 3 when viewed in the direction of travel.

LIST OF REFERENCE NUMBERS

[0027] 1 a Longitudinal frame

[0028] 1 b Longitudinal frame

[0029] 2 a Crossbeam

[0030] 2 b Crossbeam

[0031] 3 Vehicle axle

[0032] 4 Four-point connecting rod

[0033] 5 Joint

[0034] 6 Joint

[0035] 7 Joint

[0036] 8 Joint

[0037] 10 Carrier bracket

[0038] 11 Longitudinal beam

[0039] 12 Longitudinal beam

[0040] 13 Molecular joint

[0041] 14 Molecular joint

[0042] 15 Vehicle wheel

[0043] 16 Vehicle wheel

[0044] 17 a Mount

[0045] 17 b Mount

[0046] 18 a Mount

[0047] 18 b Mount

[0048] 19 Spring assembly unit

[0049] 20 Spring assembly unit

[0050] 21 Axle strut

[0051] 30 Joint ball

[0052] 31 Elastomer

[0053] 32 Housing

[0054] 33 Joint axis

[0055] 34 Outer ball

[0056] 35 Shock absorber

[0057] 36 Shock absorber

Claims

1. Axle suspension for rigid axles of vehicles, especially air-cushioned utility vehicles, with: a said twistable four-point connecting rod (4), which is connected above the said vehicle axle (3) to the said vehicle axle (3), on the one hand, and to the said vehicle body (1, 2), on the other hand, via two said joints (5, 6, 7, 8) each, which are arranged at spaced locations from one another in the longitudinal direction of the vehicle, at least one said spring assembly unit (19, 20) per vehicle side, which is located for springing between the said vehicle axle (3) and the said vehicle body (1, 2), and a said axle strut (21) for axle guiding, which extends approximately in the middle of the vehicle in the longitudinal direction of the vehicle and connects the said vehicle axle (3) to the said vehicle body (1, 2) in a vertically movable manner.

2. Axle suspension in accordance with claim 1, characterized in that the said longitudinal beams (11, 12) arranged on the said vehicle axle (3) have at least one said mount (17, 18) each for the said spring assembly units (19, 20) or said shock absorbers (35, 36).

3. Axle suspension in accordance with claim 2, characterized in that the said mounts (17, 18) for the said spring assembly units (19, 20) or for the said shock absorbers (35, 36) are designed as joints.

4. Axle suspension in accordance with claim 3, characterized in that the joints are ball-and-socket joints.

5. Axle suspension in accordance with one of the above claims, characterized in that the said vehicle body (1, 2) has two said parallel longitudinal frames (1a, 1b) and said crossbeams (2a, 2b), which connect the said longitudinal beams approximately in the transverse direction of the vehicle and are arranged at spaced locations from one another.

6. Axle suspension in accordance with claim 5, characterized in that the said axle strut (21) having said molecular joints (13, 14) on both sides is connected to a said crossbeam (2a or 2b) on the side of the said vehicle axle (3) located opposite the said four-point connecting rod (4), on the one hand, and via a said support bracket (10), on the other hand.

7. Axle suspension in accordance with one of the above claims, characterized in that the said spring assembly unit (19, 20) is arranged in front of or behind the said vehicle axle (3).

8. Axle suspension in accordance with one of the claims 1 through 6, characterized in that a said spring assembly unit (19, 20) each is arranged in front of and behind the said vehicle axle (3).