Assembly with axle steering unit as a vibration damper for a vehicle

Abstract

The invention relates to an assembly 100 for a vehicle 1000, comprising an axle carrier frame 10 and an axle steering unit 20, wherein the axle carrier frame 10 has a plurality of receiving points 11 for attaching a wheel suspension, wherein the axle carrier frame 10 has a plurality of fastening points 12 for attaching the axle carrier frame 10 to the vehicle 1000, wherein the axle steering unit 20 is configured to change the position of a wheel 301, and wherein the axle steering unit 20 is elastically mounted on the axle carrier frame 10.

Description

[0001] The invention relates to an assembly with an axle steering unit as a vibration damper for a vehicle, as well as a rear axle comprising such an assembly. State of the art

[0002] Axle supports in vehicles transmit the forces between the wheels and the rest of the vehicle. To do this, axle supports in vehicles carry the axle and its wheels and are arranged to the rest of the vehicle. The wheels are connected to the axle support via a wheel suspension. Axle supports for the rear axle can have axle steering, which can change the position of the wheels suspended on the axle support. The axle steering is rigidly connected to the axle support. The axle support is set into vibration by shocks, vibrations, and oscillations that occur at the axle and wheels. These vibrations can penetrate into the interior of the vehicle. To reduce the spread and generation of vibrations, additional elements are arranged on the axle support. These are simple spring-mass components that dampen or cancel out the spread and generation of vibrations.Such vibration dampers have no function other than damping vibrations. The vibration damper on the axle carrier primarily dampens or cancels out any pitching motion of the axle carrier.

[0003] However, this state-of-the-art technology has the problem that the vibration absorber increases the mass of the axle carrier and thus the vehicle, requiring additional assembly work. The complexity of the suspension also increases. With a rigid, i.e., non-elastic, connection of the axle steering unit to the axle carrier frame, the axle steering unit immediately follows every movement or vibration of the axle carrier frame, especially low-frequency ones. An additional element is required to absorb the vibrations of the axle carrier frame.

[0004] The object of the invention is to reduce the mass of the axle carrier and to further ensure effective cancellation of the vibration of the axle carrier. Disclosure of the invention

[0005] The invention solves the problem by means of an assembly with an elastic mounting of an axle steering unit on an axle support frame and by dispensing with an additional element whose exclusive function is to absorb the vibrations of the axle support frame.

[0006] The assembly according to the invention thus reduces the number of components, manufacturing costs and mass of the assembly compared to a design with an additional element whose exclusive function is to absorb the vibrations of the axle support frame.

[0007] The assembly for a vehicle comprises an axle support frame and an axle steering unit. The axle support frame has a plurality of mounting points for connecting a wheel suspension. The axle support frame has a plurality of fastening points for connecting the axle support frame to the vehicle. The axle steering unit is configured to change the position of a wheel. The axle steering unit is elastically mounted on the axle support frame. The axle steering unit forms a vibration damper for the vibrations of the assembly.

[0008] An elastic connection is one that allows relative movement of the axle steering unit relative to the axle support frame. If the axle support frame is subject to vibration, particularly low-frequency vibration, the axle steering unit does not follow the movement of the axle support frame immediately, but rather with a time delay. This delayed movement of the axle steering unit relative to the axle support frame dampens or cancels out the vibration or movement of the axle support frame.

[0009] The subclaims show preferred developments of the invention.

[0010] Preferably, the elastic mounting of the axle steering unit on the axle support frame enables the axle steering unit to vibrate relative to the axle support frame. The resonant frequency of the assembly lies in a frequency range of 15 to 100 Hz, in particular in a frequency range of 30 to 60 Hz, preferably in a frequency range of 20 to 50 Hz. The resonant frequency is determined by the mass and moment of inertia of the axle support frame, the mass and moment of inertia of the axle steering unit, the lever arm of the axle steering unit relative to the axle support frame, and the spring stiffness of the mounting of the axle steering unit on the axle support frame. This design of the assembly allows for particularly effective damping, or cancellation, of the vibrations occurring in the axle support frame by the axle steering unit.

[0011] Advantageously, the axle support frame has a first bearing point, a second bearing point, and a third bearing point. The axle steering unit is movably connected to the axle support frame via a first bearing at the first bearing point, a second bearing at the second bearing point, and a third bearing at the third bearing point. The center of gravity of the axle steering unit lies between the first bearing, the second bearing, and the third bearing. A movable connection of the axle steering unit relative to the axle support frame means an elastic connection according to the above design. Thus, the vibration mode of the axle steering unit relative to the axle support frame is determined by the three bearings.

[0012] Particularly advantageously, the first bearing, the second bearing, and the third bearing are designed as rubber bearings. Configuring the first bearing, the second bearing, and the third bearing as rubber bearings allows relative movement of the axle steering unit relative to the axle support frame at each of the three bearings and in any direction, thus damping or canceling the relative movement of the axle steering unit relative to the axle support frame in any direction. This design allows vibrations or movements of the axle support frame to be dampened or canceled in any direction by the first bearing, the second bearing, and the third bearing.

[0013] Alternatively or additionally, the axle steering unit has a connecting fork. The axle steering unit is configured to move the connecting fork translationally along a connecting fork axis. The connecting fork is configured to change the position of the wheel when the connecting fork is displaced along the connecting fork axis. The first bearing and the second bearing are designed as pivot bearings, rotatable about the same axis of rotation. The axis of rotation is parallel to the connecting fork axis.

[0014] This design of the first bearing and the second bearing supports the translational movement of the connecting fork along the connecting fork axis. Forces resulting from a translational movement of the connecting fork are transmitted via the first bearing to the first bearing point and via the second bearing to the second bearing point, without any relative movement of the first bearing to the first bearing point or a relative movement between the second bearing and the second bearing point being possible. Thus, any movement of the axle steering unit along the connecting fork axis resulting from a movement of the connecting fork along the connecting fork axis is prevented. This allows for a direct and precise implementation of a change in the position of the wheel by means of a translational movement of the connecting fork along the connecting fork axis.

[0015] Preferably, the first bearing and the second bearing are designed as pivot bearings with a rubber buffer, a so-called silent bearing. This allows both damping or absorption of the vibrations of the axle support frame and improved support of a translational movement of the connecting fork along the connecting fork axis compared to a rubber buffer alone.

[0016] Preferably, a first bearing stroke of the first bearing, a second bearing stroke of the second bearing, and a third bearing stroke of the third bearing are 0.3 mm to 1 mm, in particular 0.6 mm to 0.8 mm. This allows for effective damping or cancellation of the vibrations of the axle support frame.

[0017] Advantageously, the third bearing is equidistant from the first bearing and the second bearing. The third bearing is arranged at a first distance from the axis of rotation. Thus, a rotational movement of the axle steering unit about the axis of rotation is dampened or prevented by the third bearing.

[0018] Particularly advantageously, the axle support frame is designed as an axle support frame for a rear axle of the vehicle. During the intended operation of the vehicle, the wheels of the rear axle have a smaller possible steering angle than the wheels of the front axle of the vehicle.

[0019] Preferably, the axle support frame is configured to pitch a transverse axis. The axle steering unit is arranged outside the transverse axis. If the axle support frame pitches about its transverse axis, a pitching movement of the axle steering unit about the transverse axis is initiated. Due to the design of the mounting of the axle steering unit on the axle support frame according to one of the preceding embodiments, a time-delayed excitation occurs, so that the temporally leading pitching movement of the axle support frame is dampened or canceled out by the movement of the axle steering unit.

[0020] Particularly preferably, the transverse axis of the axle support frame corresponds to a Y-axis of the vehicle.

[0021] Particularly preferably, the rotational axis is aligned parallel to the transverse axis. When the axle support frame pitches about its Y-axis, this results in particularly good transmission of the axle support frame's pitching motion to the axle steering unit. This also results in particularly strong damping or cancellation of the axle support frame's pitching motion.

[0022] Advantageously, vibration of the axle support frame is absorbed by the axle steering unit. No additional vibration absorber is mounted on the axle support frame other than the axle steering unit. This reduces the weight of the assembly. Furthermore, the design reduces the manufacturing effort and costs for the assembly.

[0023] The invention further comprises a rear axle. The rear axle has an assembly according to one of the previous embodiments, a first rear wheel with a first wheel suspension, and a second rear wheel with a second wheel suspension. The first rear wheel is arranged on the axle support frame via the first wheel suspension, and the second rear wheel is arranged via the second wheel suspension. The first rear wheel is connected to the first connecting fork via a first guide rod, and the second rear wheel is connected to the axle steering unit via a second guide rod, such that the position of the first rear wheel and the second rear wheel can be changed by the axle steering unit. The rear axle requires no additional vibration dampers and has all the advantages of the assembly according to one of the previous embodiments.

[0024] Furthermore, the invention encompasses a vehicle having a rear axle according to the previous embodiment. Thus, the vehicle has all the advantages of the previous embodiment of the rear axle.

[0025] The axle steering unit preferably comprises an actuator, a drive, a shaft, the connecting fork, a housing, and a support plate. The actuator is configured to change a rotational position of the shaft by means of the drive. The shaft is connected to the connecting fork in such a way that a change in the rotational position of the shaft changes the position of the connecting fork. The actuator, the drive, the shaft, the connecting fork, and the housing are arranged on the support plate. The support plate is mounted on the axle support frame. Such a configuration of the axle steering unit allows for precise and reliable adjustment of the position of the connecting fork.

[0026] Particularly preferably, the axle steering unit has a mass of one-quarter to one-tenth, in particular one-sixth to one-eighth, of the mass of the axle support frame. This allows for particularly effective damping or absorption of vibration or movement of the axle support frame.

[0027] Further details, features, and advantages of the invention will become apparent from the following description and the figures. They show: Fig. 1 is a schematic representation of a vehicle with an assembly according to a first embodiment of the invention, and Fig. 2 a schematic representation of an assembly according to the first embodiment of the invention.

[0028] Fig. 1 shows a schematic representation of a vehicle 1000 with an assembly 100 according to a first embodiment of the invention. The vehicle 1000 has an X-axis 41, a Y-axis 42, and a Z-axis 43. The axle support frame 10 is designed as an axle support frame 10 for a rear axle 300 of the vehicle 1000. During the intended operation of the vehicle 1000, the two rear wheels 301 of the rear axle 300 have a smaller possible steering angle than the two front wheels 201 of a front axle 200 of the vehicle 1000.

[0029] Fig.2 shows a schematic representation of an assembly 100 according to the first exemplary embodiment of the invention. The assembly 100 has an axle support frame 10 and an axle steering unit 20. The axle support frame 10 has a plurality of receiving points 11 for connecting a first wheel suspension and a second wheel suspension. The axle support frame 10 has a plurality of fastening points 12 for connecting the axle support frame 10 to the vehicle 1000. The axle steering unit 20 is configured to change a position of a first rear wheel 301 and a position of a second rear wheel. The axle steering unit 20 is elastically mounted on the axle support frame 10. The elastic mounting of the axle steering unit 20 on the axle support frame 10 provides the axle steering unit 20 with the ability to oscillate relative to the axle support frame 10. The axle steering unit 20 forms a vibration damper for the vibrations of the assembly 100.

[0030] If the axle support frame 10 is subject to vibration, particularly at a low frequency, the axle steering unit 20 does not follow the movement of the axle support frame 10 immediately, but rather with a time delay. This delayed movement of the axle steering unit 20 relative to the axle support frame 10 dampens or cancels out the movement of the axle support frame 10. With a rigid, i.e., non-elastic, connection of the axle steering unit 20 to the axle support frame 10, the axle steering unit 20 immediately follows every movement or vibration, particularly at a low frequency, of the axle support frame 10. The movement or vibration of the axle support frame 10 is dampened or canceled out by the axle steering unit 20. No additional element is required to cancel out the vibrations of the axle support frame 10.

[0031] A resonance frequency of the assembly 100 lies in a frequency range of 20 to 50 Hz. This allows for particularly effective damping or cancellation of the vibrations occurring in the axle support frame 10 by the axle steering unit 20.

[0032] The axle support frame 10 has a first bearing point 13, a second bearing point 14, and a third bearing point 15. The axle steering unit 20 is movably connected to the axle support frame 10 via a first bearing 31 at the first bearing point 13, via a second bearing 32 at the second bearing point 14, and via a third bearing 33 at the third bearing point 15. The center of gravity of the axle steering unit 20 lies in the triangle between the first bearing 31, the second bearing 32, and the third bearing 33.

[0033] The axle steering unit 20 has an actuator, a drive, a shaft, a first connecting fork 21 and a second connecting fork 22, a housing, and a support plate. The actuator is configured to change a rotational position of the shaft by means of the drive. The shaft is connected to the first connecting fork 21 and the second connecting fork 22 such that a change in the rotational position of the shaft changes the position of the first connecting fork 21 and the second connecting fork 22. The actuator, the drive, the shaft, the first connecting fork 21, the second connecting fork 22, and the housing are arranged on the support plate. The support plate is mounted on the axle support frame 10. The axle steering unit 20 is configured to move the first connecting fork 21 and the second connecting fork 22 translationally along a connecting fork axis 23.The first connection fork 21 is configured to change a position of the first rear wheel 301 upon displacement of the first connection fork 21 along the connection fork axis 23. The second connection fork 22 is configured to change a position of the second rear wheel upon displacement of the second connection fork 21 along the connection fork axis 23. The first bearing 31 and the second bearing 32 are designed as pivot bearings rotatable about the same axis of rotation 30. The axis of rotation 30 is arranged parallel to the connection fork axis 23.

[0034] This configuration of the first bearing 31 and the second bearing 32 supports the translational movement of the first connecting fork 21 and the second connecting fork 22 along the connecting fork axis 23. Forces resulting from a translational movement of the first connecting fork 21 and the second connecting fork 22 are transmitted via the first bearing 31 to the first bearing point 13 and via the second bearing 32 to the second bearing point 14, without any relative movement of the first bearing 31 to the first bearing point 13 or any relative movement between the second bearing 32 and the second bearing point 14. Thus, any movement of the axle steering unit 20 along the connecting fork axis 23 is prevented by a movement of the first connecting fork 21 and the second connecting fork 22 along the connecting fork axis 23.This allows a direct and precise implementation of a change in a wheel position by means of a translational movement of the first connection fork 21 and the second connection fork 22 along the connection fork axis 23.

[0035] The third bearing 33 is designed as a rubber bearing. The third bearing 33 is spaced at the same distance 33a, 33b from the first bearing 31 and the second bearing 32. The third bearing 33 is arranged at a first distance 33c from the rotational axis 30. Thus, a rotational movement of the axle steering unit 20 about the rotational axis 30 is dampened by the third bearing 33. A third bearing stroke of the third bearing 33 is 0.6 mm to 0.8 mm. This allows for effective damping or cancellation of the vibrations of the axle support frame 10.

[0036] The axle support frame 10 is configured to pitch about a transverse axis 16. The axle steering unit 20 is arranged outside the transverse axis 16. If the axle support frame 10 pitches about its transverse axis 16, a pitching movement of the axle steering unit 20 about the transverse axis 16 is initiated. Due to the design of the mounting of the axle steering unit 20 on the axle support frame 10 according to the first embodiment, a time-delayed excitation of the axle steering unit occurs, so that the temporally leading pitching movement of the axle support frame 10 is dampened or canceled out by the movement of the axle steering unit 20.

[0037] The transverse axis 16 of the axle support frame 10 is parallel to the Y-axis 42 of the vehicle 1000. The rotation axis 30 is aligned parallel to the transverse axis 16. A pitching movement of the axle support frame 10 about its transverse axis 16 results in a particularly good transmission of the pitching movement of the axle support frame 10 to the axle steering unit 20. This also results in a particularly strong damping, or cancellation, of the pitching movement of the axle support frame 10.

[0038] The axle steering unit 20 has one-sixth the mass of the axle support frame 10. This allows for particularly effective damping or absorption of vibration or movement of the axle support frame 10. List of reference symbols: 10 axle support frames 11 reception points 12 attachment points 13 first storage location 14 second storage location 15 third storage location 16 Transverse axis of the axle support frame 20 axle steering unit 21 first connecting fork 22 second connecting fork 23 Connecting fork axle 30 axis of rotation 31 first camp 32 second camp 33 third camp 33a Distance from first bearing to third bearing 33b Distance between second bearing and third bearing 33c first distance 41 X-axis 42 Y-axis 43 Z-axis 100 assembly 200 front axle 201 front wheels 300 rear axle 301 first rear wheel

Claims

[1] Assembly (100) for a vehicle, comprising - an axle support frame (10), and - an axle steering unit (20), - wherein the axle steering unit (20) is arranged to change a position of a wheel (301), and - wherein the axle steering unit (20) is elastically mounted on the axle support frame (10). [2] Assembly (100) according to claim 1 characterized by , that - the elastic mounting of the axle steering unit (20) on the axle support frame (10) enables the axle steering unit (20) to oscillate relative to the axle support frame (10), - wherein the axle steering unit (20) has its resonance frequency relative to the axle support frame (10) in a frequency range of 15 to 100 Hz, in particular in a frequency range of 30 to 60 Hz, preferably in a frequency range of 20 to 50 Hz. [3] Assembly (100) according to one of the preceding claims characterized by , that - the axle support frame (10) has a first bearing point (13), a second bearing point (14) and a third bearing point (15), and - the axle steering unit (20) is movably connected to the axle support frame (10) via a first bearing (31) at the first bearing point (13), via a second bearing (32) at the second bearing point (14) and via a third bearing (33) at the third bearing point (15), - wherein the center of gravity of the axle steering unit (20) lies between the first bearing (31), the second bearing (32) and the third bearing (33). [4] Assembly (100) according to claim 3 characterized by , that - the first bearing (31), the second bearing (32) and the third bearing (33) are designed as rubber bearings, and / or - the axle steering unit (20) has a connecting fork (21, 22), - wherein the axle steering unit (20) is arranged to move the connecting fork (21, 22) translationally along a connecting fork axis (23), - wherein the connecting fork (21, 22) is arranged to change a position of the wheel (301) when the connecting fork (21, 22) is displaced along the connecting fork axis (23), - the first bearing and the second bearing (32) are designed as pivot bearings rotatable about the same axis of rotation (30), and - wherein the rotation axis (30) is oriented parallel to the connection fork axis (23). [5] Assembly (100) according to one of claims 3 or 4 characterized by that a first bearing stroke of the first bearing (31), a second bearing stroke of the second bearing (32) and a third bearing stroke of the third bearing (33) comprise 0.3 mm to 1 mm, in particular 0.6 mm to 0.8 mm. [6] Assembly (100) according to one of claims 3 to 5 characterized by , that - the third bearing (33) has the same distance (33a, 33b) from the first bearing (31) and the second bearing (32), and - the third bearing (33) is arranged at a first distance (33c) from the axis of rotation (30). [7] Assembly (100) according to one of the preceding claims characterized by , that - the axle support frame (10) is designed as an axle support frame (10) for a rear axle (300) of the vehicle (1000), - wherein wheels (301) of the rear axle (300) have a smaller possible steering angle during the intended operation of the vehicle (1000) than wheels (201) of a front axle (200) of the vehicle (1000). [8] Assembly (100) according to one of the preceding claims characterized by , that - the axle support frame (10) is arranged to pitch a transverse axis (16), - wherein the axle steering unit (20) is arranged outside the transverse axis (16). [9] Assembly (100) according to claim 8, characterized bythat the axis of rotation (30) is aligned parallel to the transverse axis (16). [10] Assembly (100) according to one of the preceding claims characterized by , that - a vibration of the axle support frame (10) is eliminated by the axle steering unit (20), - wherein no further vibration damper is arranged on the axle support frame (10). [11] Rear axle (300) having - an assembly (100) according to one of the preceding claims, and - a first rear wheel (301) with a first wheel suspension and a second rear wheel with a second wheel suspension, - wherein the first rear wheel (301) is arranged on the axle support frame (10) via the first wheel suspension and the second rear wheel is arranged on the axle support frame (10) via the second wheel suspension, - wherein the first rear wheel is connected to the axle steering unit (20) via a first guide rod to a first connecting fork (21, 22) and the second rear wheel is connected to the axle steering unit (20) via a second guide rod to the second connecting fork (21, 22), so that the position of the first rear wheel (301) and the second rear wheel can be changed by the axle steering unit (20).

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