STEERING SYSTEM WITH AN ACTUATING DEVICE, AND USE OF THE STEERING SYSTEM WITH ACTUATING DEVICE

Abstract

A steering system with an actuating device (1), in particular a rear axle steering system, having a spindle drive (3) with a spindle (5) and a spindle nut (4) which is fitted into the housing (2) of the steering system in a positionally fixed but rotatable manner and is driven by an electric motor (9). The electric motor (9) is a vernier motor that drives the spindle drive (3) and is integrated in the spindle drive (3). The actuating device (1) is used for a rear axle steering system of a motor vehicle.

Claims

1-6. (canceled)

7. A steering system with an actuating device (1) comprising: a spindle drive (3) with a spindle (5) and a spindle nut (4) fitted into a housing (2) of the steering system in a positionally fixed but rotatable manner, the steering system having an electric motor (9), and the electric motor (9) being a vernier motor and being coupled to the spindle drive (3) as a drive input.

8. The steering system according to claim 7, wherein the vernier motor (9) defines a longitudinal axis and is arranged such that the longitudinal axis of the vernier motor is parallel to a longitudinal axis of the spindle (5) and the spindle nut (4), and the spindle nut (4) is drivable by the vernier motor (9) by way of either a traction drive with a drive belt (8) or a planetary gearset.

9. The steering system according to claim 7, wherein the vernier motor (9) is arranged coaxially with the spindle (5).

10. The steering system according to claim 9, wherein the vernier motor (9) has a stator rotationally fixed relative to the housing (2), and a rotor, fitted to rotate inside the stator, is coupled to the spindle nut (4).

11. The steering system according to claim 10, wherein the rotor is coupled to the spindle nut (4) by a gear system.

12. A rear axle steering system with an actuating device (1) comprising: a spindle drive (3) with a spindle (5) and a spindle nut (4) fitted into a housing (2) of the steering system in a positionally fixed but rotatable manner, the steering system having an electric motor (9), and the electric motor (9) being a vernier motor and being coupled to the spindle drive (3) as a drive input.

13. A rear axle steering system of a vehicle in combination with an actuating device (1), the actuating device comprising: a spindle drive having a spindle and a spindle nut, the spindle nut being supported by bearings within a housing such that the spindle nut is rotatable about a longitudinal axis and axially fixed relative to the housing; a vernier motor being drivingly coupled to the spindle so that rotation of the vernier motor rotationally drives the spindle nut about the longitudinal axis; the spindle nut having a threading that mates with threading of the spindle such that rotation of the spindle nut drives the spindle axially along the longitudinal axis of the spindle nut relative to the housing; a first end of the spindle being connected to a shaft such that the spindle and the shaft are rotationally and laterally fixed relative to each other, the shaft being supported by a slide bearing such that the shaft is only movable along the longitudinal axis relative to the slide bearing, and the slide bearing is supported by the housing such that the shaft is movable along the longitudinal axis relative to the housing; and the shaft being connectable to a wheel of the vehicle, and an axial side of the housing opposite the shaft is articulated to the vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0016] An example embodiment of the invention is illustrated in a sole drawing and will be described in greater detail below so that further features and/or advantages can emerge from the description and/or the sole drawing. The sole FIGURE shows an actuating device having a compact electric motor drive.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The sole FIGURE shows a longitudinal section of the structure of a simple electric actuator 1 (also referred to as an actuating device), i.e. one that acts on only one wheel, for a rear axle steering system of a motor vehicle. The actuator 1 has a multi-component housing 2 in which is arranged a spindle drive 3 comprising a spindle nut 4 and a spindle 5 that engages with the spindle nut 4 and can be displaced axially. The spindle 5 has a spindle thread or outer thread 5a and the nut has a nut thread or inner thread 4a, which are in the form of a movement thread, preferably a trapezoid thread. The spindle nut 4, which is supported rotatably in the housing 2 by two roller bearings 6 and 7, is driven via a belt drive 8 by an electric motor 9. The housing 2 comprises three housing components, namely a central housing component 2a in which the spindle nut 4 is fitted, a component 2b on the vehicle side via which the actuator 1 is articulated to the vehicle, and a component 2c on the wheel side at the end of which a slide bearing 10 is arranged. The spindle 5 has an end side 5b which is connected in a rotationally and laterally fixed manner to a screw-on shaft 11. The screw-on shaft 11 has a slide bearing section (not indexed) that passes through the slide bearing 10. At the end 11a of the screw-on shaft 11 that projects out of the housing 2c, a joint 12 is attached via a pivot bolt 12a, which joint can be connected by way of a steering rod (not shown) such as a track rod, or even connected directly, to a steerable rear wheel of the motor vehicle, which wheel is mounted by means of a wheel carrier on the body of the vehicle in a rotatable and steerable manner. The outer part 11a of the screw-on shaft 11 that projects out of the housing 2c is sealed by a flexible seal in the form of a bellows 13, which encloses on one side the housing 2c and on the other side the pivot bolt 12a. The slide bearing 10 and the slide bearing section of the screw-on shaft 11 that can move in the slide bearing 10 are provided with anti-rotation means (not shown here). The drawing shows how small the fitting space required is thanks to the electric motor. Thanks to that, the actuating device or actuator has a slim overall shape.

Indexes

[0018] 1 Actuator [0019] 2 Housing [0020] 2a Central housing component [0021] 2b Housing component on the vehicle side [0022] 2c Housing component on the wheel side [0023] 3 Spindle drive [0024] 4 Spindle nut [0025] 4a Nut thread [0026] 5 Spindle [0027] 5a Spindle thread [0028] 5b Spindle end [0029] 6 Roller bearing [0030] 7 Roller bearing [0031] 8 Belt drive [0032] 9 Electric motor [0033] 11 Slide bearing [0034] 11 Screw-on shaft [0035] 11a Outer part [0036] 11b Inner part [0037] 12 Joint [0038] 12a Pivot bolt [0039] 13 Bellows