Damping arrangement for an axle of a motor vehicle and motor vehicle

Abstract

Damping arrangement (10) of an active suspension for an axle of a motor vehicle, wherein a damping system interacts with each wheel of the axle, each of the damping systems comprising the following assemblies: A damper comprising a double-acting hydraulic cylinder and a piston, wherein the damper is coupleable to a wheel suspension system of the respective wheel. A hydraulic pump and an electric motor for driving the respective hydraulic pump, wherein the hydraulic pump can be driven by the electric motor in different directions of rotation to provide different delivery directions.A hydraulic unit comprising a hydraulic reservoir and valves, wherein the hydraulic pump and the hydraulic unit of the respective damping system interact with hydraulic chambers of the hydraulic cylinder of the respective damping system such that, depending on the delivery direction of the hydraulic pump of the hydraulic unit, movement of the piston in a first actuation direction or in a second actuation direction is provided, wherein the hydraulic pumps and the electric motors of both damping systems are combined to form a motor-pump unit (28). The motor-pump unit (28) is attached to a subframe (30) or subframe of the axle via a support (29).

Description

[0001] The invention relates to a damping arrangement of an active chassis of a motor vehicle for an axle of the motor vehicle and to a motor vehicle.

[0002] DE 10 2017 117 658 B4 and DE 10 2019 115 492 B4 each disclose a damping system for a wheel of a motor vehicle, comprising a damper, a hydraulic pump driven by an electric motor, a hydraulic reservoir, and a plurality of valves. The damper is formed by a double-acting hydraulic cylinder and a piston movable back and forth within the cylinder. The hydraulic pump is coupled to hydraulic chambers of the hydraulic piston via hydraulic lines, whereby, depending on the delivery direction of the hydraulic pump, a movement of the piston in a first actuation direction or in a second actuation direction can be provided.

[0003] A motor vehicle axle comprises two wheels that are attached to a subframe or subframe via corresponding wheel suspensions. A subframe is attached to the vehicle body via bearings, without being decoupled. A subframe is attached to the vehicle body without being decoupled.

[0004] On an axle of an active chassis, a damping system is provided for each wheel. The two damping systems for the two wheels of an axle are part of a damping arrangement for the respective axle of the vehicle.

[0005] From DE 10 2019 118 384 A1, it is known that the electric motor and the hydraulic pump of a damping system of a respective wheel of an axle of an active chassis are combined into a motor-pump group. A common electronic unit interacts with both motor-pump groups of a respective axle to control the electric motors. The electronic unit is installed between the two motor-pump groups. The two motor-pump groups form a motor-pump unit, which is installed via mounts on the motor vehicle, preferably near the respective axle. The common electronic unit is a component of the motor-pump unit of the damping arrangement.

[0006] DE 10 2018 122 226 A1 discloses a subframe on the chassis of a motor vehicle for accommodating a motor-pump group of a damping system of an active chassis.

[0007] In practice, it has been shown that the motor-pump unit of a damping arrangement of an axle of an active chassis vibrates significantly while the motor vehicle is moving, particularly due to excitations from the road surface. This is a disadvantage. Therefore, there is a need for a damping arrangement of an axle of an active chassis of a motor vehicle in which the motor-pump unit of the damping arrangement vibrates less.

[0008] The object of the invention is to provide a damping arrangement for an axle of an active chassis of a motor vehicle in which the motor-pump unit vibrates less without affecting noise generation and thus without impairing the acoustics while the motor vehicle is moving. Furthermore, a motor vehicle with such a damping arrangement is to be provided.

[0009] This object is achieved by a damping arrangement according to patent claim 1 and by a motor vehicle according to patent claim 12.

[0010] In the damping arrangement according to the invention, the motor-pump unit is fastened via a support to a subframe or to a subframe of the axle of the active chassis, preferably to connection areas of the subframe or subframe for a stabilizer.

[0011] In the damping arrangement according to the invention, the motor-pump unit is attached via a support to the subframe or subframe of the axle of an active chassis, preferably to connection areas of the subframe or subframe for a stabilizer. This is preferred to ensure that the motor-pump unit of the damping arrangement of the axle of the active chassis vibrates less during the vehicle's travel, without affecting noise generation and thus without impairing the acoustics.

[0012] It is possible to shift the natural frequencies of the motor-pump unit as far as possible from the range of existing excitation frequencies, e.g. by wheel excitation, without impairing the acoustics.

[0013] Preferably, the support is attached to the connection areas of the subframe or to the connection areas of the subframe for a stabilizer instead of a stabilizer, with the support extending into the installation space for the stabilizer instead of a stabilizer. This is particularly preferred in order to further reduce the vibration tendency of the motor-pump unit of the damping arrangement of the axle of the active chassis, without impairing the acoustics.

[0014] According to a first variant of the invention, the motor-pump unit of the damping arrangement of the axle of the active chassis is arranged below the support, wherein the support is rigidly connected to the subframe or subframe, and wherein either the motor-pump unit is rigidly connected to the support or the motor-pump unit is connected to the support via bearings which have a bearing stiffness of between 450 N / mm and 850 N / mm, preferably between 500 N / mm and 800 N / mm, particularly preferably between 550 N / mm and 750 N / mm or between 600 N / mm and 700 N / mm in the radial direction of the bearing and thus in the longitudinal and vertical directions of the motor vehicle.

[0015] According to a second variant of the invention, the motor-pump unit of the damping arrangement of the axle of the active chassis is integrated into the carrier in such a way that the motor-pump unit divides the carrier into two sections and that one of the sections of the carrier extends on either side of the motor-pump unit, wherein either the carrier is rigidly connected to the subframe or subframe or the carrier is connected to the subframe or subframe via bearings which have a bearing stiffness of between 450 N / mm and 850 N / mm in the radial direction of the bearing and thus in the longitudinal and vertical directions of the motor vehicle, preferably between 500 N / mm and 800 N / mm, particularly preferably between 550 N / mm and 750 N / mm or between 600 N / mm and 700 N / mm.

[0016] Both the first and second variants of the invention can reduce the vibration tendency of the motor-pump unit of the damping arrangement of the axle of the active chassis while the motor vehicle is moving. Which variant is chosen depends in particular on the available installation space in the area of ​​the subframe or subframe.

[0017] Preferred developments of the invention will become apparent from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail, without being limited thereto, with reference to the drawings. Herein: Fig. 1 a schematic representation of hydraulic assemblies of a damping arrangement according to the invention for the wheels of an axle of an active chassis of a motor vehicle according to the invention; Fig. 2 shows a section of a motor vehicle according to the invention in the area of ​​a subframe and a motor-pump unit of the damping arrangement according to the invention; Fig. 3 a detail of the Fig. 2; Fig. 4 an alternative to the detail of the Fig. 2; Fig. 5 a diagram to illustrate the effect or influence of the damping arrangement according to the invention on the vibration of the motor-pump unit of the damping arrangement.

[0018] A motor vehicle, such as a passenger car, has multiple axles. Each axle has two wheels, which typically engage a subframe of the respective axle via corresponding wheel suspensions. The subframe of the respective axle engages a vehicle body via bearings in a decoupled manner. The wheel suspensions can also engage a subframe, which is not decoupled from the vehicle body. Subframes can preferably be used in the area of ​​a rear axle, and subframes can preferably be used in the area of ​​a front axle. The invention is described below for the case in which the wheel suspensions engage a subframe.

[0019] If the respective axle of the motor vehicle is the axle of an active chassis of the motor vehicle, a damping arrangement 10 is provided for the two wheels of the axle of the active chassis, whereby Fig. 1 shows a preferred embodiment of a damping arrangement 10 for the two wheels of an axle of an active chassis of a motor vehicle.

[0020] The damping arrangement 10 of an axle of the active chassis has a damping system 10a, 10b for each wheel of the axle.

[0021] Each of the damping systems 10a, 10b has a damper 11, which can be coupled to a wheel suspension system (not shown) for the respective wheel (not shown). The respective damper 11 is formed by a double-acting hydraulic cylinder 12 and a piston 13, wherein the piston 13 is movable back and forth within the hydraulic cylinder 12, specifically in Fig. 1 upwards and downwards. The hydraulic cylinder 12 of each of the damping systems 10a, 10b, designed as a double-acting hydraulic cylinder, has a hydraulic chamber 14, 15 on each side of the piston 13.

[0022] Depending on which of the two hydraulic chambers 14, 15 hydraulic oil is supplied to and from which of the two hydraulic chambers 15, 14 hydraulic oil is discharged, the piston 13 can be displaced either in a first actuation direction or in an opposite second actuation direction. The first actuation direction of the piston 13 is actuated in the pulling direction, and the second actuation direction of the piston 13 is actuated in the pushing direction.

[0023] Each damping system 10a, 10b further includes a hydraulic pump 16, which is driven by a respective electric motor 17. The hydraulic pump 16 and the electric motor 17 of each damping system 10a, 10b form a respective motor-pump group 18. The hydraulic pump 16 is a reversing pump, which can be driven in different directions of rotation by the respective electric motor 17 to provide different flow directions.

[0024] The respective damping system 10a, 10b of the Fig. 1 further comprises a hydraulic unit 19, which has a hydraulic reservoir 20 and valves 21, 22, 23, 24. The valves 21, 22 are check valves, and the valves 23, 24 are damping valves. The hydraulic reservoir 20 of each of the damping systems 10a, 10b engages hydraulic lines of the hydraulic unit 19 between the check valves 21, 22 and between the damping valves 23, 24, which are coupled to the hydraulic chambers 14, 15.

[0025] Depending on the delivery direction of the hydraulic pump 16 and preferably also depending on the position of the valves 21, 22, 23, 24 of the respective damping system, oil is supplied to the hydraulic chamber 14 and oil is removed from the hydraulic chamber 15 to displace the piston 13 in the first direction of movement, i.e. in the pulling direction, or oil is supplied to the hydraulic chamber 15 and oil is removed from the hydraulic chamber 14 to provide a second direction of movement of the piston 13 in the second direction of movement, i.e. in the pushing direction.

[0026] The hydraulic pump 16 of the motor-pump group 18 of the respective damping system 10a, 10b is connected via hydraulic lines 25, 26 to the hydraulic unit 19 of the respective damping system 10a, 10b, which comprises the hydraulic reservoir 20 and the valves 21, 22, 23, 24 and is preferably installed as a unit on the damper 12 or on the hydraulic cylinder 13.

[0027] A common control device 27 interacts with the motor-pump groups 18 of the two damping systems 10a, 10b of the damping arrangement 10 of the axle of the active chassis. The electric motors 17 of the two motor-pump assemblies 18 can be controlled by the common control device 27.

[0028] The two motor-pump groups 18 of the two damping systems 10a, 10b and the common control device 27 form a motor-pump unit 28 of the damping arrangement 10. The present invention relates to details of the damping arrangement 10 that ensure that the motor-pump unit 28 of the damping arrangement 10 of the axle of the active chassis of the motor vehicle vibrates less intensely while the motor vehicle is traveling, without affecting noise development and thus without impairing the acoustics.

[0029] The motor-pump unit 28 of the damping arrangement 10 of the axle of an active chassis of a motor vehicle is fastened via a support 29 to a subframe 30 or subframe of the axle, specifically in the preferred embodiment shown to connection areas 31 of the subframe 30 for a stabilizer.

[0030] In this case, the support 29 extends into the installation space for the stabilizer instead of a stabilizer, whereby the support 29 engages the connection areas 31 of the subframe 30 for a stabilizer or is attached to these connection areas 31 instead of the stabilizer. The support 29 can also be referred to as a stabilizer replacement rod.

[0031] Fig. Figure 2 shows a first variant of a damping arrangement 10 according to the invention together with a subframe 30. Bearings 32 are shown on the subframe 30, which serve to connect the subframe 30 to a vehicle body (not shown). Furthermore, the connection areas 31 of the subframe 30 for a stabilizer are shown.

[0032] In the preferred embodiment, the support 29 of the motor-pump unit 28 of the damping assembly 10 engages the axle having the subframe 30 at the connection areas 31 of the subframe 30 for a stabilizer instead of a stabilizer. A longitudinal axis of the support 29 preferably extends along a space that would actually be intended for the stabilizer.

[0033] Fig. 2 shows that the support 29 is fastened at its opposite ends via flanges 33 to the connection areas 31 of the subframe 30 for the stabilizer via fastening screws 34, wherein the connection areas 31 of the stabilizer 30 are also formed by flanges against which the flanges 33 come into contact.

[0034] Fig. 3 shows the carrier 29 of the motor-pump unit 28 together with the motor-pump unit 28 in a stand-alone view without the subframe 30.

[0035] In the example of Fig. 2 and Fig. 3, the motor-pump unit 28 is arranged below the support 29. The support 29 is rigidly connected to the subframe 30 via the flanges 33, wherein Fig. 3 the motor-pump unit 28 is connected to the carrier 29 via bearings 35.

[0036] The bearings 35 have a defined bearing stiffness in the radial direction of the respective bearing 35, and thus in the longitudinal and vertical directions of the motor vehicle. This bearing stiffness of the bearings 35 in the radial direction is in particular between 450 N / mm and 850 N / mm, preferably between 500 N / mm and 800 N / mm, particularly preferably between 550 N / mm and 750 N / mm, or between 600 N / mm and 700 N / mm.

[0037] This radial bearing stiffness is an average radial bearing stiffness of the respective bearing 35. This average radial bearing stiffness is preferably measured in a range between 0.2 mm and 0.7 mm of a bearing 35 deformed in the radial direction in the deformation direction of the bearing 35.

[0038] The axial bearing stiffness, i.e. the bearing stiffness in the transverse direction of the motor vehicle, is of secondary importance for the present invention.

[0039] The axial bearing stiffness of the respective bearing 35 is smaller or lower than the radial bearing stiffness, in particular 15% to 30% smaller or lower than the radial bearing stiffness.

[0040] The bearings 35 are made of NR rubber or NBR rubber. The rubber used preferably has a hardness of 60 ± 5 Shore A.

[0041] Although in Fig. 2 and Fig. 3, the motor-pump unit 28 of the damping arrangement 10 of the axle of an active chassis engages elastically on the support 29 via the bearings 35, and the support 29 rigidly engages on the subframe 30, it is alternatively also possible for the motor-pump unit 28 to be rigidly attached to the support 29. Alternatively, corresponding rubber-elastic bearings could also be provided in the area between the flanges 33 and the connection areas 31 of the subframe 30.

[0042] Then, when, as in Fig. 2 and Fig. 3, the motor-pump unit 28 of the damping arrangement 10 of the axle of an active chassis is arranged below the carrier 29, however, the Fig. 2 and Fig. 3, in which the motor-pump unit 28 is elastically fastened to the support 29 via the bearings 35 and the support 29 is rigidly fastened to the subframe 30, is preferred.

[0043] Fig. 4 shows an alternative to Fig. 3, in which the motor-pump unit 28 of the damping arrangement 10 of the axle of an active chassis is integrated into the support 29, in such a way that the motor-pump unit 28 interrupts the support 29 or divides it into sections 29a, 29b, so that one of the sections 29a or 29b of the support 29 extends on each side of the motor-pump unit 28.

[0044] In Fig. 4, the motor-pump unit 28 of the damping arrangement 10 of the axle of an active chassis is preferably rigidly connected to the respective section 29a, 29b of the support 29. The support 29, namely its sections 29a and 29b, are preferably connected to the chassis subframe 30 via bearings 35, wherein these bearings in turn have a defined bearing stiffness in the radial direction of the bearing 35 and thus in the longitudinal and vertical directions of the motor vehicle.

[0045] The defined bearing stiffnesses have already been defined above for the example of the Fig. 2, Fig. 3 and are also found in the embodiment of the Fig. 4 Application.

[0046] Although in the case where the motor-pump unit 28 is integrated into the carrier 29, the Fig. 4 is preferred, it is also possible to Fig. 4 to mount the motor-pump unit 28 via corresponding bearings on the respective sections 29a and 29b in a rubber-elastic manner and then to rigidly attach the sections 29a and 29b to the subframe 30. Likewise, both the motor-pump unit 28 could be rigidly connected to the sections 29a, 29b of the support 29, and the sections 29a, 29b of the support 29 could each be rigidly connected to the subframe 30.

[0047] Fig. Figure 5 illustrates the effect of the invention with the curves SX, SY, SZ, and SX', SY', and SZ'. The dashed curves SX, SY, and SZ show vibrations of the motor-pump unit 28 according to the prior art.

[0048] The curves SX', SY' and SZ' show vibrations of the motor-pump unit 28 that develop using the invention, with SX and SX' each visualizing vibrations in the vehicle's longitudinal direction, SZ and SZ' vibrations in the vehicle's vertical direction, and SY and SY' vibrations in the vehicle's transverse direction. Fig. In Figure 5 the accelerations a are plotted for the oscillations over the frequency f. Fig. From Figure 5, it can be seen that the invention significantly reduces the accelerations for the critical vibrations in the vehicle's longitudinal direction X and vertical direction Z. The acceleration maxima shift toward higher frequencies f. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 117 658 B4

[0002] DE 10 2019 115 492 B4

[0002] DE 10 2019 118 384 A1

[0005] DE 10 2018 122 226 A1

[0006]

Claims

[1] Damping arrangement (10) of an active chassis for an axle of a motor vehicle, wherein a damping system (10a, 10b) interacts with each wheel of the axle, wherein each of the damping systems (10a, 10b) has the following assemblies: a damper (11) having a double-acting hydraulic cylinder (12) and a piston (13), wherein the damper (11) can be coupled to a wheel suspension system of the respective wheel, a hydraulic pump (16) and an electric motor (17) for driving the respective hydraulic pump (16), wherein the hydraulic pump (16) can be driven in different directions of rotation by the electric motor (17) to provide different delivery directions, a hydraulic unit (19) having a hydraulic reservoir (20) and valves (21, 22, 23, 24), wherein the hydraulic pump (16) and the hydraulic unit (19) of the respective damping system (10a, 10b) interact with hydraulic chambers (14, 15) of the hydraulic cylinder (12) of the respective damping system (10a, 10b) such that, depending on the conveying direction of the hydraulic pump (16) of the hydraulic unit (19), a movement of the piston (13) in a first actuating direction or in a second actuating direction can be provided, wherein the hydraulic pumps (16) and the electric motors (17) of both damping systems (10a, 10b) are combined to form a motor-pump unit (28), characterized by , that the motor-pump unit (28) is attached to a subframe (30) or to a subframe of the axle via a support (29). [2] Damping arrangement according to claim 1, wherein the support (29) is fastened to connection areas (31) of the subframe (30) or subframe for a stabilizer. [3] Damping arrangement according to claim 2, wherein the support (29) extends in the installation space for the stabilizer instead of the stabilizer. [4] Damping arrangement according to claim 1, 2 or 3, wherein the motor-pump unit (28) is arranged below the carrier (29). [5] Damping arrangement according to claim 4, wherein the motor-pump unit (28) is rigidly connected to the carrier (29). [6] Damping arrangement according to claim 4, wherein the motor-pump unit (28) is connected to the carrier (29) via bearings (35) which have a bearing stiffness in the radial direction of the bearing (35) and thus in the longitudinal and vertical directions of the motor vehicle of between 450 N / mm and 850 N / mm, preferably between 500 N / mm and 800 N / mm, particularly preferably between 550 N / mm and 750 N / mm or between 600 N / mm and 700 N / mm. [7] Damping arrangement according to claim 4, 5 or 6, wherein the support (29) is rigidly connected to the subframe (30) or subframe. [8] Damping arrangement according to claim 1, 2 or 3, wherein the motor-pump unit (28) is integrated into the carrier (29) such that the motor-pump unit (28) divides the carrier (29) into two sections (29a, 29b) and that one of the sections (29a, 29b) of the carrier (19) extends on each side of the motor-pump unit (28). [9] Damping arrangement according to claim 8, wherein the motor-pump unit (28) is rigidly connected to the carrier (29). [10] Damping arrangement according to claim 8 or 9, wherein the support (29) is rigidly connected to the subframe (30) or subframe [11] Damping arrangement according to claim 8 or 9, wherein the carrier (29) is connected to the subframe (30) or subframe via bearings (35) which have a bearing stiffness in the radial direction of the bearing (35) and thus in the longitudinal and vertical directions of the motor vehicle of between 450 N / mm and 850 N / mm, preferably between 500 N / mm and 800 N / mm, particularly preferably between 550 N / mm and 750 N / mm or between 600 N / mm and 700 N / mm. [12] Motor vehicle with several axles, each axle being assigned a damping arrangement (10) according to one of claims 1 to 11.

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