Rotation limiting means, steering system, and method for limiting a rotational movement in a steering system

Abstract

A rotation limiting means for a steer-by-wire steering system comprises a fixedly arranged outer housing and a steering column which is received at least partially in the outer housing and can be rotated relative to the outer housing. Furthermore, at least one actuating member is provided which is arranged between the outer housing and the steering column and can be rotated to a limited extent relative to the outer housing and relative to the steering column, in order to mechanically limit a rotation of the steering column relative to the outer housing. Furthermore, a steering system and a method for limiting a rotational movement in a steering system are described.

Claims

1. A rotation limiting means for a steer-by-wire steering system, comprising: a fixedly arranged outer housing and a steering column which is received at least partially in the outer housing and can be rotated relative to the outer housing, wherein at least one actuating member having a radially inwardly projecting bearing section is provided which is arranged between the outer housing and the steering column and can be rotated to a limited extent relative to the outer housing and relative to the steering column, in order to mechanically limit a rotation of the steering column relative to the outer housing.

2. The rotation limiting means as defined in claim 1, wherein the steering column is configured as a driver which drives the actuating member via the bearing section in the case of rotation of the steering column by a defined rotational angle.

3. The rotation limiting means as defined in claim 2, wherein the actuating member rotates together with the steering column relative to the outer housing from the defined rotational angle in the case of rotation of the steering column.

4. The rotation limiting means as defined in claim 3, wherein the actuating member is a hollow shaft.

5. The rotation limiting means as defined in claim 2, wherein the steering column has at least one radially outwardly projecting driver section, the driver section driving the actuating member via the bearing section.

6. The rotation limiting means as defined in claim 1, wherein the at least one actuating member includes two or more actuating members arranged between the outer housing and the steering column, at least one of the actuating members having the bearing section.

7. The rotation limiting means as defined in claim 6, wherein at least one of the actuating members is a sliding element which slides along a predefined track.

8. The rotation limiting means as defined in claim 7, wherein the predefined track is formed by a groove.

9. The rotation limiting means as defined in claim 1, wherein the actuating member has a radially outwardly projecting rotation limiting section.

10. The rotation limiting means as defined in claim 9, wherein the outer housing has a radially inwardly projecting stop.

11. The rotation limiting means as defined in claim 1, wherein the steering column rotates the actuating member via the bearing section relative to the outer housing.

12. The rotation limiting means as defined in claim 1, wherein the at least one actuating member includes a first actuating member that is slidable along a predefined track relative to the outer housing, and a second actuating member having the bearing section.

13. The rotation limiting means as defined in claim 12, wherein the steering column drives the first actuating member along the predefined track until the first actuating member engages the bearing section, the first and second actuating members rotating together with the steering column relative to the outer housing after the first actuating member engages the bearing section.

14. A method for limiting a rotational movement in a steering system, a steering column being rotated in a rotational direction relative to a stationary outer housing, the steering column bearing against a radially inwardly projecting bearing section of an actuating member from a defined rotational angle, the actuating member is rotated further in the rotational direction together with the steering column until the actuating member bears against the outer housing when a limiting angle is reached, in order to mechanically limit the relative rotational movement of the steering column relative to the outer housing.

15. The method as defined in claim 14, wherein the steering column has at least one radially outwardly projecting driver section, the driver section driving the actuating member via the bearing section.

16. The method as defined in claim 15, wherein the actuating member has a radially outwardly projecting rotation limiting section, the outer housing has a radially inwardly projecting stop, and the actuating member rotates in the rotational direction together with the steering column until the rotation limiting section bears against the stop when the limiting angle is reached.

17. The method as defined in claim 15, wherein the actuating member includes a first actuating member that is slidable along a predefined track relative to the outer housing and a second actuating member having the bearing section, the driver section of the steering column driving the first actuating member along the predefined track until the first actuating member engages the bearing section, the first and second actuating members rotating together with the steering column relative to the outer housing after the first actuating member engages the bearing section and until the second actuating member bears against the outer housing.

18. The rotation limiting means as defined in claim 10, wherein the steering column has at least one radially outwardly projecting driver section, the driver section driving the actuating member via the bearing section.

19. The rotation limiting means as defined in claim 18, wherein the at least one actuating member includes a first actuating member that is slidable along a predefined track relative to the outer housing, and a second actuating member having both the bearing section and the rotation limiting section.

20. The rotation limiting means as defined in claim 19, wherein the driver section of the steering column drives the first actuating member along the predefined track until the first actuating member engages the bearing section, the first and second actuating members rotating together with the steering column relative to the outer housing after the first actuating member engages the bearing section and until the rotation limiting section bears against the stop.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and properties of the invention result from the following description and the drawings, to which reference is made and in which:

(2) FIG. 1 shows a diagrammatic view of a steering system according to the invention,

(3) FIG. 2a shows a first sectional view of a rotation limiting means according to the invention in accordance with a first embodiment, in a first state,

(4) FIG. 2b shows a second sectional view of a rotation limiting means according to the invention in accordance with a first embodiment, in a second state,

(5) FIG. 2c shows a sectional view of a rotation limiting means according to the invention in accordance with a first embodiment, in a third state,

(6) FIG. 3a show a first sectional view of a rotation limiting means according to the invention in accordance with a second embodiment, in a first state,

(7) FIG. 3b shows a second sectional view of a rotation limiting means according to the invention in accordance with a second embodiment, in a second state,

(8) FIG. 3c shows a third sectional view of a rotation limiting means according to the invention in accordance with a second embodiment, in a third state,

DETAILED DESCRIPTION

(9) FIG. 1 diagrammatically shows a steering system 10 which is configured as a steer-by-wire steering system, that is to say as a steering system without a mechanical connection to a rack 11.

(10) The steering system 10 comprises a steering wheel 12, to which a steering column 14 is fastened on the end side.

(11) Furthermore, the steering system 10 comprises a steering wheel actuator 16 which is assigned to the steering column 14, in particular is coupled to the steering column 14 at the end which is opposite the steering wheel 12.

(12) The steering column 14 is received at least partially in an outer housing 18, with respect to which the steering column 14 can be rotated in a relative manner. In this respect, the steering column 14 is shown using dashed lines in FIG. 1.

(13) In addition, the steering system 10 comprises a rotation limiting means 20 which encloses the steering column 14 and the outer housing 18 at least partially.

(14) Moreover, the rotation limiting means 20 has an actuating member 22 which is arranged between the outer housing 18 and the steering column 14. The actuating member 22 cannot be seen in FIG. 1, but can be seen in FIGS. 2 and 3, to which reference is still to be made in the following text.

(15) The actuating member 22 can fundamentally be rotated relative to the outer housing 18 and relative to the steering column 14.

(16) FIGS. 2a to 2c show a rotation limiting means 20 in different positions, in each case in the same sectional illustration.

(17) It is apparent from FIGS. 2a to 2c that the actuating member 22 is configured as a hollow shaft which lies between the steering column 14 which is configured as a solid shaft and the substantially hollow outer housing 18 which is arranged in a rotationally fixed manner.

(18) In other words, the actuating member 22 can be called an additional rotational layer, since it can be rotated to a limited extent relative to the outer housing 18 and relative to the steering column 14.

(19) It becomes clear from FIG. 2a, in which a neutral or starting position is shown, that the steering column 14 has a radially outwardly projecting driver section 24 which is configured as a lug which has two opposed sides.

(20) The opposed sides of the driver section 24 serve in each case as driver faces 26, 28 which interact with the actuating member 22. In other words, the driver section 24 has two opposed driver faces 26, 28.

(21) Furthermore, the actuating member 22 has a radially inwardly projecting bearing section 30 which likewise comprises two opposed bearing faces 32, 34. The bearing section 30 is likewise configured as a lug which extends radially to the inside.

(22) It has already become clear from FIGS. 2b and 2c that the driver section 24 interacts with the bearing section 30 when the steering column 14 is rotated relative to the outer housing 18, as will still be explained in the following text.

(23) Furthermore, the actuating member 22 has a radially outwardly projecting rotation limiting section 36 which has two opposed rotation limiting faces 38, 40.

(24) Furthermore, the outer housing 18 has a radially inwardly projecting stop 42 which comprises two opposed stop faces 44, 46. The stop 42 of the outer housing 18 interacts with the rotation limiting section 36 of the actuating member 22 in the case of a relative rotation of the steering column 14 when the limiting angle of the permissible relative rotation is reached, as is likewise apparent from FIGS. 2b and 2c.

(25) The driver section 24, the bearing section 30, the rotation limiting section 36 and the stop 42 are in each case configured as radially inwardly projecting or radially outwardly projecting lugs in relation to the otherwise rotationally symmetrically configured steering column 14, actuating member 22 and outer housing 18.

(26) Furthermore, it is apparent from FIGS. 2a to 2c that both the driver section 24, the bearing section 30, the rotation limiting section 36 and the stop 42 are configured in one piece with the respective associated component of the rotation limiting means 20.

(27) It is apparent from FIGS. 2b and 2c which in each case show the end positions of the rotation limiting means 20 and the associated steering system 10 that the steering column 14 is configured as a driver which drives the actuating member 22 in the case of rotation of the steering column 14 by a defined rotational angle.

(28) In the present case, the defined rotational angle is approximately 150°.

(29) In the case of the defined rotational angle, the steering column 14 bears via one of the two driver faces 26, 28 against the associated bearing face 32, 34 of the bearing section 30 of the actuating member 22.

(30) In the case of a further rotation beyond the defined rotational angle, the steering column 14 drives the actuating member 22 via the respective driver face 26, 28, with the result that the steering column 14 is rotated further together with the actuating member 22 in the respective rotational direction until the actuating member 22 bears via its rotation limiting section 36, in particular the respective rotation limiting face 38, 40, against the stop 42 of the outer housing 18, in particular the respective associated stop face 44, 46.

(31) This corresponds to the respective end position of the rotation limiting means 20, which end positions are shown in FIGS. 2b and 2c. FIG. 2b shows the end position for the rotation counter to the clockwise direction, whereas FIG. 2c shows the end position for a rotation in the clockwise direction.

(32) The overall relative rotational movement of the steering column 14 with respect to the outer housing 18 is in total approximately 260°, that is to say more than 180°, in the embodiment which is shown.

(33) This is due to the fact that the steering column 14 is first of all adjusted relative to the actuating member 22, the steering column 14 driving the actuating member 22 and rotating further in the corresponding rotational direction relative to the outer housing 18 until the actuating member 22 bears against the fixedly arranged outer housing 18, in order to mechanically limit the relative rotational movement of the steering column 14 relative to the outer housing 18.

(34) In addition, it is apparent from FIG. 2a which shows the starting position of the rotation limiting means 20 or the steering system 10 that the stop 42 and the driver section 24 of the steering column 14 lie substantially opposite one another in the starting position. Merely the actuating member 22 which is configured as a hollow shaft lies in between. This ensures that as great a relative rotational movement of the steering column 14 with respect to the outer housing 18 as possible is enabled.

(35) FIGS. 3a to 3c show a second embodiment of the rotation limiting means 20 which differs from the embodiment shown in FIGS. 2a to 2c in that the rotation limiting means 20 comprises two actuating members 22, that is to say a first actuating member 22a and a second actuating member 22b.

(36) Here, the first actuating member 22a is configured as a sliding element which can slide along a predefined track which is formed by way of a groove. In this respect, the first actuating element 22a or the sliding element slides within the groove.

(37) In an analogous way with respect to the first embodiment, the second actuating member 22b is configured as a hollow shaft which interacts with the outer housing 18 in an analogous way, as has been described above.

(38) In contrast to the first embodiment which is shown in FIGS. 2a to 2c, the steering column 14 adjusts the first actuating member 22a, that is to say the sliding element, from the defined rotational angle. The steering column 14 drives the sliding element within the groove until the sliding element, that is to say the first actuating member 22a, interacts with the second actuating member 22b, in order to enable a common relative rotation of the steering column 14, the first actuating member 22a and the second actuating member 22b relative to the fixedly arranged outer housing 18.

(39) On account of the two actuating members 22, a greater rotation angle range can be achieved until the relative rotational movement of the steering column 14 with respect to the outer housing 18 is limited mechanically. In the present example, this is the case at a relative rotational angle of approximately 400°.

(40) If the relative rotational angle range is to be increased further, further actuating members 22 can be provided between the steering column 14 and the outer housing 18, which further actuating members 22 interact with one another in each case, in order to transmit the rotational movement which emanates from the steering column 14 in each case to the next actuating member 22 on the radial outside. This takes place until the last or radially outermost actuating member 22 bears against the outer housing 18 in the case of the limit angle being reached, in order to mechanically limit the relative rotation of the steering column 14 with respect to the outer housing 18.

(41) In this respect, limiting of the relative rotation of the steering column 14 with respect to the outer housing 18 is possible in the case of a steer-by-wire steering system, without changing the steering wheel actuator 16. Accordingly, the latter can still be of comparatively small configuration. This is possible, since the limiting of the relative rotation takes place in a mechanical way via the rotation limiting means 20.

(42) The steering system 10 is therefore of simple configuration and is nevertheless compact, the steering system 10, in particular the rotation limiting means 20, being configured to absorb the forces and torques which occur. In addition, the relative rotational angle which can be achieved can be set via the number of actuating members 22.