Steering arrangement of a vehicle

Abstract

The invention relates to a steering arrangement (1) of a vehicle (100), comprising a steering housing (2), a rack (3), a ball screw drive (4) which interacts with the rack (3), and a bearing unit (5) by means of which the ball screw drive (4) is mounted in the steering housing (2), wherein the bearing unit (5) is designed as a radial spherical plain bearing.

Description

[0001] The invention relates to a steering arrangement of a vehicle, and a vehicle.

[0002] Vehicle steering assemblies designed as electric power steering systems are known from the prior art. Such steering assemblies typically comprise a servomotor that generates motor torque based on the steering input of the vehicle driver, providing motor assistance for the steering operation. Steering assemblies are known in which the motor torque is transmitted to a rack via a ball screw drive. The rack then transmits the steering movement to the vehicle's wheels. Under high forces, partial bending of the rack can occur during operation. This can result in deflections in the area of ​​the ball screw drive that deviate from the optimal axial alignment of the rack. This can lead to undefined loads and even malfunctions of the ball screw drive. Furthermore, the precision of the steering movement can be limited in known steering assemblies.

[0003] It is therefore an object of the present invention to provide a steering arrangement of a vehicle which provides an optimized design to enable particularly precise steering.

[0004] This object is achieved by the features of independent claim 1. The subclaims contain preferred developments of the invention.

[0005] The problem is thus solved by a vehicle steering assembly comprising a steering housing, a rack, a ball screw, and a bearing unit. The ball screw interacts with the rack. The bearing unit supports the ball screw in the steering housing. The bearing unit is designed as a radial spherical plain bearing.

[0006] In particular, a steering housing is considered to be a fixed housing, in particular fixed relative to a body of the vehicle.

[0007] The ball screw and the rack are in particular designed to interact in such a way that, in particular in response to a torque generated on the ball screw, the rack is moved in the axial direction of the rack.

[0008] A radial spherical plain bearing is considered to be a bearing that has a spherical body held by bearing shells and is movable relative to the bearing shells. For example, such a bearing is also known as a uniball bearing.

[0009] In other words, a steering assembly is provided that has a radial spherical plain bearing by means of which the ball screw is mounted in the steering housing. The radial spherical plain bearing allows the ball screw to move relative to the steering housing about any axis that is orthogonal to the longitudinal axis of the rack. In other words, the radial spherical plain bearing allows a certain amount of tilting of the rack and ball screw.

[0010] The steering arrangement therefore offers the advantage of enabling particularly precise steering movements with a particularly simple and cost-effective design. The radial spherical plain bearing allows a certain amount of tilting of the rack, which can occur under high transverse or bending forces, while ensuring a particularly robust, backlash-free bearing of the ball screw relative to the steering housing in the axial direction. This means that the radial spherical plain bearing allows slight tilting in the area of ​​the ball screw, while axial movements are suppressed particularly reliably. For example, due to the particularly low elasticity in the system, unwanted movements of the rack and thus deflections of the wheels can be effectively avoided. Furthermore, desired steering movements can be implemented particularly effectively and very precisely.This enables particularly precise steering, especially at very high vehicle speeds where, for example, only minimal steering movements are carried out.

[0011] The bearing unit preferably has a convex inner joint part. Furthermore, the bearing unit preferably has a concave outer joint part. In particular, the inner joint part is at least partially formed as a spherical, for example, ball-shaped body. The outer joint part has a corresponding concave surface in which the inner joint part rests, for example, flatly and can thus rotate. This allows for a particularly simple, cost-effective, and at the same time robust design of the bearing unit.

[0012] Preferably, the outer joint part is an integral component of the steering housing. In other words, the steering housing forms the outer joint part. This allows for a particularly simple and cost-effective design of the steering assembly with few components.

[0013] Preferably, the inner joint part is formed as a single-piece component. Alternatively, or additionally, the outer joint part is preferably formed as a single-piece component. This allows for a particularly simple and robust construction with few components. Alternatively, the inner joint part and / or outer joint part can each be formed from multiple parts.

[0014] Preferably, the bearing unit is arranged radially between the ball screw and the steering housing. In particular, the bearing unit is arranged at the level of the ball screw in the axial direction of the rack. This allows for optimal mechanical support of the ball screw while maintaining a compact design.

[0015] More preferably, the steering assembly further comprises a further bearing, which is arranged, preferably radially, between the ball screw and the bearing unit. In particular, the further bearing can be configured to enable relative rotation, in particular about the longitudinal axis of the rack, of the ball screw and the bearing unit. This can provide particularly reliable smooth running of the steering assembly.

[0016] Preferably, the additional bearing is designed as a rolling bearing. For example, the additional bearing can be designed as a ball bearing. This allows for particularly low friction in the steering system.

[0017] Particularly preferably, the bearing unit mounts the ball screw directly in the steering housing. This means that no further elements are present between the bearing unit and the steering housing, or between the bearing unit and the ball screw. In particular, the steering arrangement thus comprises, at least in the region of the ball screw, no further bearings apart from the bearing unit. In particular, the bearing unit is designed to permit the rotational movement of the ball screw. This means that the bearing unit is especially designed to enable a ball screw nut of the ball screw to rotate relative to the steering housing. This makes it possible to provide a particularly simple, cost-effective, and robust design of the steering arrangement.

[0018] The bearing unit is preferably made of steel. This means that the inner and outer joint parts are made of steel. This enables particularly simple and cost-effective production and a particularly robust design of the bearing unit.

[0019] The steering assembly preferably further comprises a motor, in particular an electric motor, which is configured to drive the ball screw drive. In particular, the electric motor is configured to rotate a ball screw nut of the ball screw drive relative to the steering housing, in particular about the longitudinal axis of the rack.

[0020] Furthermore, the invention leads to a vehicle, in particular a motor vehicle, preferably a passenger car, comprising the described steering arrangement. In particular, the steering arrangement is part of an electric power steering system of the vehicle.

[0021] Further details, features, and advantages of the invention will become apparent from the following description and the figures. They show: Fig. 1 is a simplified schematic view of a vehicle with a steering arrangement according to a first embodiment of the invention, Fig. 2 a detailed sectional view of the steering arrangement of the Fig. 1, and Fig. 3 a detailed sectional view of a steering arrangement according to a second embodiment of the invention.

[0022] Preferred embodiments of a steering arrangement 1 of a vehicle 100 are described below. Fig. 1 to 3. Identical or functionally equivalent components are always provided with the same reference numerals.

[0023] Fig. 1 shows a simplified schematic perspective view of the vehicle 100. The vehicle 100 is a motor vehicle, in particular a passenger car.

[0024] The vehicle 100 comprises a steering arrangement 1 according to the invention on its front wheel axle 20 in the direction of travel 101.

[0025] Fig. 2 shows a detailed sectional view of the steering assembly 1 of the first embodiment of the invention.

[0026] The steering arrangement 1 comprises a steering housing 2, which is, for example, firmly connected to a body of the vehicle 100.

[0027] In addition, the steering assembly 1 comprises a rack 3, which extends along a longitudinal axis 30. The longitudinal axis 30 is in particular parallel to the wheel axis 20.

[0028] The steering assembly 1 also comprises a ball screw 4 and an electric motor 7. The electric motor 7 is configured to rotate a ball screw nut 41 of the ball screw 4 about the longitudinal axis 30 by means of a motor torque. Due to the interaction of the ball screw 4 with the rack 3, in particular via the ball screw nut 41 and balls 42 and a corresponding screw thread of the rack 3, the rotation of the ball screw nut 41 causes a translational movement of the rack 3 along the longitudinal axis 30.

[0029] In particular, the operation of the motor 7 can be carried out in such a way as to provide motor support for steering movements which are generated by a driver of the vehicle 100 on a steering wheel 105 and transmitted via a steering rod 106.

[0030] The steering arrangement 1 further comprises a bearing unit 5, which is designed as a radial spherical plain bearing, and a further bearing 6, which is arranged radially between the ball screw drive 4 and the bearing unit 5.

[0031] The additional bearing 6 allows the relative rotation of the ball screw nut 41 to the bearing unit 5 and the steering housing 2.

[0032] The bearing unit 5 has a convex inner joint part 51, which is spherical in particular on its radially outer side. Furthermore, the bearing unit 5 has a concave outer joint part 52, which holds the inner joint part 51, particularly on its radially inner side.

[0033] The outer joint part 52 is designed as an integral component of the steering housing 2.

[0034] The bearing unit 5 is located in the axial direction at the level of the ball screw 4.

[0035] The bearing unit 5, as a radial spherical plain bearing, allows a certain rotation of the ball screw 4 relative to the joint housing 2 about an axis orthogonal to the longitudinal axis 30 by the relative rotation of the inner joint part 51 and the outer joint part 52. In Fig. In Figure 2, such a pivoting movement is indicated by arrow 10. This allows for compensation of bending or tilting of the rack 3, which can occur, for example, when large forces are applied to the rack 3.

[0036] The possibility of tilting ensures particularly smooth and low-wear operation of the ball screw 4.

[0037] In addition, the radial spherical plain bearing allows for a particularly precise and robust axial support of the ball screw 4 in the joint housing 2. Specifically, the radial spherical plain bearing as a bearing unit 5 can absorb and transmit high axial forces. Due to its design, a clearance-free bearing in the axial direction can be provided particularly easily and precisely. In particular, the robust construction of the radial spherical plain bearing also allows for essentially no or very minimal elasticity in the axial direction.

[0038] This has the advantage that the axial deflection or positioning of the rack 3 in the steering assembly 1 can be carried out particularly precisely. This, in turn, results in a particularly precise transmission of the steering movements to the wheels 107 of the vehicle 100. Especially at very high speeds, minimal steering movements can be carried out particularly precisely and reliably.

[0039] Fig. Figure 3 shows a detailed sectional view of a steering arrangement 1 according to a second embodiment of the invention. The second embodiment essentially corresponds to the first embodiment of the Fig. 1 and Fig. 2, with the difference that no additional bearing is arranged between the ball screw 4 and the bearing unit 5. This means that the bearing unit 5 supports the ball screw 4 directly in the steering housing 2.

[0040] In other words, the inner joint part 51 is the only element in the radial direction that is arranged between the ball screw nut 41 and the steering housing 2 or the outer joint part 52.

[0041] In the second embodiment, the relative rotatability between the ball screw nut 41 and the steering housing 2 is provided by the bearing unit 5, in detail by counter-rotating about the longitudinal axis 30 of the inner joint part 51 and the outer joint part 52.

[0042] The steering arrangement 1 of the second embodiment is thus characterized by a particularly simple, cost-effective and robust construction with particularly few components. List of reference symbols: 1 steering arrangement 2 steering housings 3 rack 4 ball screw 5 storage unit 6 additional camps 7 Electric motor 10 Swivel movement 20 front wheel axle 30 Longitudinal axis 41 Ball screw nut 42 balls 51 inner joint part 52 Outer joint part 100 vehicles 101 Direction of travel 105 Steering wheel 106 Handlebar 107 wheels

Claims

[1] Steering arrangement of a vehicle (100), comprising: - a steering housing (2), - a rack (3), - a ball screw (4) which interacts with the rack (3), and - a bearing unit (5) by means of which the ball screw (4) is mounted in the steering housing (2), - wherein the bearing unit (5) is designed as a radial spherical plain bearing. [2] Steering arrangement according to claim 1, wherein the bearing unit (5) has an inner joint part (51) which is convex and an outer joint part (52) which is concave. [3] Steering arrangement according to claim 2, wherein the outer joint part (52) is an integral part of the steering housing (2). [4] Steering arrangement according to claim 2 or 3, wherein the inner joint part (51) and / or the outer joint part (52) is / are each formed as a one-piece component. [5] Steering arrangement according to one of the preceding claims, wherein the bearing unit (5) is arranged radially between the ball screw drive (4) and the steering housing. [6] Steering arrangement according to one of the preceding claims, further comprising a further bearing (6) which is arranged, in particular radially, between the ball screw drive (4) and the bearing unit (5). [7] Steering arrangement according to claim 6, wherein the further bearing (6) is designed as a rolling bearing. [8] Steering arrangement according to one of claims 1 to 5, wherein the bearing unit (5) supports the ball screw drive (4) directly in the steering housing (2). [9] Steering arrangement according to one of the preceding claims, further comprising a motor (7), in particular an electric motor, which is arranged to drive the ball screw drive (4). [10] Vehicle comprising a steering arrangement (1) according to one of the preceding claims.

Images