STEERING DEVICE FOR A VEHICLE

Abstract

A steering device for a vehicle, having an actuator which is designed to apply an axial force to a push rod. The push rod is connected to a respective steering rod on both sides in an articulated manner, and each steering rod is connected to a respective steering arm in an articulated manner. Each steering arm is operatively connected to a respective wheel carrier in order to rotate a respective wheel of a vehicle axle about a respective steering axis according to an axial movement of the push rod and has at least one first and a second arm section. The two arm sections of each steering arm can be moved towards each other in an axial direction in order to change a transmission ratio of the steering device when the wheels are being steered and to reduce the axial force on the actuator.

Claims

1-9. (canceled)

10. A steering device for a vehicle, comprising an actuator (1) provided to act upon a push-rod (2) with an axial force, the push-rod (2) is articulated on both sides to a respective track rod (5a, 5b), and the respective track rod (5a, 5b) is articulated to a respective steering arm (6a, 6b), to turn a respective wheel (8a, 8b) of a vehicle axle (9) about a respective steering axis (13a, 13b) in accordance with an axial movement of the push-rod (2) the steering arm (6a, 6b) concerned is functionally connected to a respective wheel carrier (7a, 7b) and has at least a first and a second arm section (10a, 10b, 10a, 10b), such that the first and the second arm sections (10a, 10b, 10a, 10b) of the steering arm concerned are movable axially relative to one another, to change a transmission ratio of the steering device during the steering of the wheels (8a, 8b) and to reduce axial force on the actuator (1), the first arm section (10a, 10a) of the steering arm (6a, 6b) concerned has a stud (3a, 3b) and the stud (3a, 3b) is held and guided in a groove (4a, 4b) formed in the respective wheel carrier (7a, 7b).

11. The steering device according to claim 10, wherein the groove (4a, 4b) in the respective wheel carrier (7a, 7b) is linear.

12. The steering device according to claim 10, wherein the groove (4a, 4b) in the respective wheel carrier (7a, 7b) is curved.

13. The steering device according to claim 10, wherein the respective steering arm (6a, 6b) is linear.

14. The steering device according to claim 10, wherein the respective steering arm (6a, 6b) is curved.

15. The steering device according to claim 10, wherein the actuator (1) is functionally connected to an input shaft (11), and the actuator (1) is provided in order to convert rotational movement of the input shaft (11) into translational movement of the push-rod (2).

16. The steering device according to claim 10, wherein the push-rod (2) is in a form of a rack bar.

17. Use of a steering device according to claim 10 in a passenger car or a utility vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Below, preferred example embodiments of the invention are explained in greater detail with reference to the drawings, which show:

[0026] FIG. 1: A greatly simplified schematic view from above, of a steering device according to the invention with two steering arms whose length can be varied,

[0027] FIG. 2: A schematic sectioned representation of the steering arm according to the invention shown in FIG. 1, and

[0028] FIG. 3: A further schematic sectioned view of the steering arm according to the invention shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] As shown in FIG. 1 a steering device according to the invention for a vehiclenot shown herecomprises an actuator 1 which is functionally connected to an input shaft 11 and a push-rod 2. The actuator 1 is provided in order to convert rotational movement of the input shaft 11 into a translation movement of the push-rod 2. Thus, when the input shaft 11 rotates in a first rotational direction the push-rod 2 moves axially toward a first wheel 8a. Correspondingly, when the input shaft 11 rotates in a second rotational direction the push-rod 2 moves axially toward a second wheel 8b. The two wheels 8a, 8b are part of a vehicle axle 9 and depending on the rotational movement of the input shaft 11 are turned by the steering device at least in part about a respective steering axis 13a, 13b.

[0030] The actuator 1 is designed to act upon the push-rod 2 with an axial force. In this case the push-rod 2 is made as one piece and has two distal ends. At each of the distal ends the push-rod 2 is articulated to a respective track rod 5a, 5b, and between the respective track rods 5a, 5b and the push-rod 2 is arranged a respective ball joint 12a, 12b. The respective track rod 5a, 5b is articulated to a respective steering arm 6a, 6b, and between the respective track rod 5a, 5b and the respective steering arm 6a, 6b a further respective ball joint 12c, 12d is arranged.

[0031] The respective steering arm 6a, 6b is functionally connected to a respective wheel carrier 7a, 7b in order to turn a respective wheel 8a, 8b of a vehicle axle 9 about the respective steering axis 13a, 13b in accordance with an axial movement of the push-rod 2. Furthermore, each steering arm 6a, 6b has a first and a second arm section 10a, 10b, 10a, 10b such that the two arm sections 10a, 10b, 10a, 10b of the respective steering arm 6a, 6b can be displaced axially relative to one another in order to change a transmission ratio of the steering device during the steering of the wheels 8a, 8b and to reduce the axial force on the actuator 1. In particular, each steering arm 6a, 6b of variable length generates a level transmission ratio, essentially constant over an entire steering angle range, at the steering device. The steering kinematics of the steering device are substantially improved.

[0032] FIGS. 2 and 3 show an enlarged depiction of the steering arm 6a, 6b shown only in greatly simplified form in FIG. 1. Although in FIGS. 2 and 3 only one of the two steering arms 6a, 6b is shown, the description applies to both of the steering arms 6a, 6b. The two steering arms 6a, 6b are identical and therefore structurally the same as one another. According to FIGS. 2 and 3 the first arm section 10a, 10a of the respective steering arm 6a, 6b has a stud 3a, 3b and the stud 3a, 3b is held and guided in a groove 4a, 4b formed in each respective wheel carrier 7a, 7b. The wheel carrier turns about the steering axis 13a, 13b in accordance with an axial movement of the push-rod 2.

[0033] The groove 4a, 4b in the respective wheel carrier 7a, 7b is curved. Due to the curved shape of each groove 4a, 4b, a steering error is minimized and as a result of that the tire wear and the rolling resistance of the vehicle are reduced. Moreover, each steering arm 6a, 6b is of linear shape. Thus, both the first arm section 10a, 10a and also the second arm section 10b, 10b of each steering arm 6a, 6b are straight.

[0034] The invention is not limited to the example embodiment described above. Other possibilities for further development can be derived from the description and the claims. In particular, individual articulated joints can also be made as rubber mountings. Furthermore other possible articulated joints are conceivable, which have at least one degree of freedom. In addition the groove 4a, 4b on the respective wheel carrier 7a, 7b can be linear. Advantageously, the respective steering arms 6a, 6b can additionally or alternatively be of curved shape.

INDEXES

[0035] 1 Actuator [0036] 2 Push-rod [0037] 3a, 3b Stud [0038] 4a, 4b Groove [0039] 5a, 5b Track rod [0040] 6a, 6b Steering arm [0041] 7a, 7b Wheel carrier [0042] 8a, 8b Wheel [0043] 9 Vehicle axle [0044] 10a, 10a First arm section [0045] 10b, 10b Second arm section [0046] 11 Input shaft [0047] 12a-12d Ball joint [0048] 13a, 13b Steering axis