Steer-by-wire system for motor vehicle

Abstract

The invention relates to a steering-by-wire system (1) of a motor vehicle, comprising a device (12), which is arranged at least in sections in a housing (10) of the steering-by-wire system (1), for mechanically limiting the rotational travel of a steering shaft (14), comprising a plurality of stop elements (16, 18), which are rotatably arranged on the steering shaft (14), the stop elements (16, 18) are each designed in such a way that stop surfaces of the stop elements (16, 18) arranged adjacent to each other abut against each other when the steering shaft (14) is rotated, the bores (16a1, 18a1) of the respective annular sections (16a, 18a) of the first stop element (16) and of the at least one second stop element (18) having a predefined clearance (24) with respect to the steering shaft (14), the stop element (16, 18) is provided with a gap (16, 18) which is designed to make the first stop surface (16b, 18b) of the corresponding stop element (16, 18) and the opposite second stop surface (16c, 18c) abut against the stop surface of the adjacent stop element (16, 18) at the same time.

Description

Technical Field

[0001] The present invention relates to a steer-by-wire system for a motor vehicle. Background Art

[0002] Within the scope of the prior art, various approaches are known for achieving a rotational angle limitation of a steering shaft of a steering system, in particular for use within the scope of steer-by-wire systems.

[0003] DE 100 17 049 A1 discloses a steering device for a motor vehicle, comprising a steering handle and a steering gear, wherein the steering handle is connected via a steering spindle which is rotationally connected thereto, wherein the torque connection between the steering spindle and the steering gear can be achieved, depending on the embodiment of the steering device, by means of mechanical, hydraulic, pneumatic or electrical transmission elements, wherein the steering spindle has an axial stop and / or a torsional stop on the low-torque side for limiting the rotational angle in both rotational directions, and a mating stop is arranged on the housing side. Summary of the Invention

[0004] The present invention is therefore based on the object of providing an improved steer-by-wire system for a motor vehicle, which has improved properties with regard to the force action in the end stops.

[0005] This object is achieved by a steer-by-wire system for a motor vehicle having the features of claim 1 .

[0006] The present invention realizes a steer-by-wire system for a motor vehicle.

[0007] The steer-by-wire system includes a device for mechanically limiting the rotational travel of a steering shaft, which is arranged at least partially in a housing of the steer-by-wire system. The device includes a plurality of stop elements rotatably arranged on the steering shaft, each of which has: an annular section through which the steering shaft is guided; a first stop surface extending radially from the annular section; and a second stop surface arranged opposite the first stop surface.

[0008] Furthermore, a first stop element is connected to the steering shaft in a rotationally fixed manner, wherein at least one second stop element is arranged adjacent to the first stop element in the axial direction of the steering shaft.

[0009] The stop elements are each configured such that the stop surfaces of adjacent stop elements abut against each other when the steering shaft is rotated. At least one end stop is disposed on the housing of the steer-by-wire system, the end stop being configured to limit the rotation of the steering shaft in two rotational directions by abutting against a stop element disposed adjacent to the end stop. The holes of the corresponding annular sections of the first stop element and the at least one second stop element have a predetermined clearance relative to the steering shaft, the clearance being configured to cause the first stop surface and the oppositely disposed second stop surface of the corresponding stop element to abut against the stop surface of the adjacent stop element simultaneously.

[0010] The idea of the present invention is to achieve an additional degree of freedom in the guide diameter between the steering spindle and the inner circumference of the respective stop element. Thus, the respective stop element can advantageously change its position within certain limits, thereby avoiding over-determination of the system due to the precise positioning of the two opposing stop faces of the respective stop element relative to the stop face of the adjacent stop element.

[0011] Advantageous embodiments and developments are apparent from the dependent claims and the description in conjunction with the drawings.

[0012] According to a preferred development, it is provided that the third stop element is arranged adjacent to the at least one second stop element, wherein the end stop is designed to limit the rotation of the steering spindle in both rotational directions by abutting the third stop element.

[0013] By providing a third stop element arranged between the second stop element and the end stop, the rotation angle of the steering shaft can be increased in an advantageous manner.

[0014] According to a further preferred development, the first stop element, the at least one second stop element and the third stop element are designed to form a force pair when a torque is introduced by the first stop surface and the second stop surface coming into contact with corresponding stop surfaces of adjacent stop elements.

[0015] Therefore can be in advantageous manner the single force that acts on the corresponding stop surface is divided equally.Can thus select the smaller size design of corresponding stop element, can realize saving to cost, weight and structural space thus.

[0016] According to a further preferred development, it is provided that the first stop element, the at least one second stop element and the third stop element are designed to limit the rotational travel of the steering shaft when no transverse forces are introduced into the steering shaft.

[0017] As a result, a smaller dimensioning of the steering shaft can be advantageously selected, which in turn likewise makes it possible to save costs, weight and installation space.

[0018] According to another preferred improvement, the gap is formed by the diameter difference between the shaft diameter of the steering shaft and the diameter of the hole of the corresponding stop element. Therefore, the optimal size design of the diameter of the steering source and the hole of the stop element can be selected, which best matches each other.

[0019] According to another preferred improvement, it is provided that the first stop element, at least one second stop element and the third stop element are constructed to be aligned relative to the steering axis when the first stop surface and the second stop surface abut against the corresponding stop surface of the adjacent stop element so that a uniform force transmission from the first stop surface and the second stop surface to the corresponding stop surface of the adjacent stop element can be performed.

[0020] The play can thus advantageously be designed in such a way that it precisely reflects positional deviations of the respective stop surfaces of the stop element.

[0021] According to another preferred embodiment, the size of the gaps between the first stop element, the at least one second stop element, and the third stop element relative to the steering shaft is substantially greater than or equal to the positional deviation of the stop surfaces of adjacent stop elements. The resulting gaps can advantageously be reduced by grease introduced into the bores of the respective stop elements.

[0022] According to another preferred embodiment, the positional deviation of the stop surfaces of adjacent stop elements is a positional deviation along the rotational direction of the stop elements. This positional deviation can thus be precisely determined, and based on this, the required clearance between the steering shaft and the bore diameter of the stop elements can then be determined.

[0023] According to another preferred refinement, the third stop element is configured to cause a first stop surface to abut a first stop surface of an adjacently arranged second stop element when the steering shaft is rotated in the first rotational direction, and the second stop surface to abut a third stop surface of at least one end stop arranged on the housing of the steer-by-wire system. Rotation of the steering shaft in the first rotational direction can thus be effectively limited.

[0024] According to another preferred refinement, the third stop element is configured to cause the first stop surface to abut against the second stop surface of the adjacent second stop element when the steering shaft is rotated in a second rotational direction opposite to the first rotational direction, and the second stop surface abuts against a fourth stop surface of at least one end stop arranged on the housing of the steer-by-wire system. Rotation of the steering shaft in the second rotational direction can thus be effectively limited.

[0025] According to another preferred refinement, the third stop element is designed to abut simultaneously against a stop surface of the second stop element and a stop surface of at least one end stop arranged on the housing of the steer-by-wire system during a rotation of the steering shaft. Thus, the abutment against the end stop can advantageously also be carried out with a uniform force distribution or torque introduction into the corresponding stop surface.

[0026] According to another preferred refinement, the stop surface of the corresponding stop element at least partially comprises a metal stop surface and at least partially comprises a stop buffer element, in particular composed of an elastomer.

[0027] According to another preferred improvement, the respective stop elements are configured to bring the respective stop-buffer elements into contact with one another when the stop surfaces of adjacent stop elements abut, thereby advantageously enabling acoustic buffering when the respective stop surfaces abut.

[0028] The described embodiments and developments can be combined with one another as desired.

[0029] Further possible embodiments, developments, and implementations of the present invention also include combinations of features of the present invention described above or below with reference to the exemplary embodiments that are not explicitly mentioned.

[0030] The accompanying drawings are intended to help further understand the embodiments of the present invention. These drawings illustrate the embodiments and, combined with the description, are used to explain the principles and solutions of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Further embodiments and several of the advantages mentioned are shown with reference to the drawings. The elements shown in the drawings are not necessarily shown true to scale relative to one another.

[0032] in: Figure 1 A schematic diagram showing a section of a steer-by-wire system for a motor vehicle according to a preferred embodiment of the present invention; Figure 2a A longitudinal sectional view showing a steer-by-wire system for a motor vehicle according to a preferred embodiment of the present invention; Figure 2b A longitudinal sectional view showing a steer-by-wire system for a motor vehicle according to a preferred embodiment of the present invention; Figure 3 a schematic diagram showing a stop element, not belonging to the present invention, of a steer-by-wire system for a motor vehicle; and Figure 4A schematic diagram of a stop element for a steer-by-wire system of a motor vehicle is shown according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0033] In the figures of the drawings, identical reference numerals denote identical or functionally identical elements, components or assemblies, unless otherwise indicated.

[0034] A steer-by-wire system 1 for a motor vehicle comprises a device 12 for mechanically limiting the rotational travel of a steering shaft 14, which is arranged at least partially in a housing 10 of the steer-by-wire system 1. The device comprises a plurality of stop elements 16, 18, 20 rotatably arranged on the steering shaft 14, each of which comprises: an annular section 16a, 18a, 20a through which the steering shaft 14 is guided; a first stop surface 16b, 18b, 20b extending radially from the annular section 16a, 18a, 20a; and a second stop surface 16c, 18c, 20c arranged opposite the first stop surface 16b, 18b, 20b.

[0035] The first stop element 16 is connected to the steering shaft 14 in a rotationally fixed manner, wherein at least one second stop element 18 is arranged adjacent to the first stop element 16 in the axial direction of the steering shaft 14. An optional third stop element 20 is also arranged adjacent to the at least one second stop element 18, wherein the stop elements 16, 18, 20 are each designed such that the stop surfaces of the stop elements 16, 18, 20 arranged adjacent to each other abut against each other when the steering shaft 14 is rotated.

[0036] Figure 2a A longitudinal section through a steer-by-wire system for a motor vehicle according to a preferred embodiment of the present invention is shown.

[0037] At least one end stop 22 is arranged on the housing 10 of the steer-by-wire system 1 , which is configured to limit the movement of the third stop element 20 by abutting against the third stop element 20 . Figure 2a The steering shaft 14 (not shown) rotates in two directions of rotation.

[0038] Figure 2b A longitudinal section through a steer-by-wire system for a motor vehicle according to a preferred embodiment of the present invention is shown.

[0039] At least one end stop 22 is arranged on the housing 10 of the steer-by-wire system 1 , which end stop is designed to limit the rotation of the steering shaft 14 in both rotational directions by abutting against the third stop element 20 .

[0040] The third stop element 20 is further configured to cause the first stop surfaces 16b, 18b, 20b to abut the first stop surfaces 16b, 18b, 20b of the adjacently arranged second stop element 18 when the steering shaft 14 is rotated in the first rotational direction, wherein the second stop surfaces 16c, 18c, 20c abut against a third stop surface 26 of at least one end stop 22 arranged on the housing 10 of the wire-controlled steering system 1.

[0041] The third stop element 20 is further configured to cause the first stop surfaces 16b, 18b, 20b to abut against the second stop surfaces 16c, 18c, 20c of the adjacently arranged second stop element 18 when the steering shaft 14 rotates in a second rotational direction opposite to the first rotational direction, wherein the second stop surfaces 16c, 18c, 20c abut against a fourth stop surface 28 of at least one end stop 22 arranged on the housing 10 of the wire-controlled steering system 1.

[0042] Figure 3 A schematic diagram of a stop element, not belonging to the present invention, for a steer-by-wire system of a motor vehicle is shown.

[0043] The stop elements 16 , 18 are designed such that the openings of the respective annular sections 16 a , 18 a of the first stop element 16 and the at least one second stop element 18 have too little play relative to the steering shaft 14 .

[0044] Therefore, the stop elements 16, 18 cannot compensate for the distance or position deviation 32 between the stop surfaces of adjacent stop elements. This in turn leads to an uneven introduction of torque to the stop surfaces of the respective stop elements.

[0045] Figure 4 A schematic diagram of a stop element for a steer-by-wire system of a motor vehicle is shown according to a preferred embodiment of the present invention.

[0046] The holes 16a1, 18a1, 20a1 of the corresponding annular sections 16a, 18a, 20a of the first stop element 16, at least one second stop element 18 and the third stop element 20 have a predetermined gap 24 relative to the steering shaft 14, which is constructed to enable the first stop surfaces 16b, 18b, 20b of the corresponding stop elements 16, 18, 20 and the oppositely arranged second stop surfaces 16c, 18c, 20c to simultaneously abut against the stop surfaces of adjacent stop elements 16, 18, 20.

[0047] The first stop element 16 , the at least one second stop element 18 and the third stop element 20 are designed to form a force pair when a torque is introduced by the first stop surfaces 16 b , 18 b , 20 b and the second stop surfaces 16 c , 18 c , 20 c coming into contact with corresponding stop surfaces of adjacent stop elements 16 , 18 , 20 .

[0048] Furthermore, the first stop element 16, the at least one second stop element 18, and the third stop element 20 are designed to limit the rotational travel of the steering shaft 14 when no transverse forces are introduced into the steering shaft 14. The gap 24 is also formed by the diameter difference between the shaft diameter of the steering shaft 14 and the diameter of the bores 16a1, 18a1, 20a1 of the respective stop elements 16, 18, 20.

[0049] The first stop element 16, at least one second stop element 18 and the third stop element 20 are further configured to be aligned relative to the steering shaft 14 when the first stop surface 16b, 18b, 20b and the second stop surface 16c, 18c, 20c abut against the corresponding stop surfaces of the adjacent stop elements 16, 18, 20 in such a way that a uniform force transmission of the first stop surface 16b, 18b, 20b and the second stop surface 16c, 18c, 20c to the corresponding stop surfaces of the adjacent stop elements 16, 18, 20 can be performed.

[0050] Here, the size of the gap 24 between the first stop element 16, the at least one second stop element 18, and the third stop element 20 relative to the steering shaft 14 is greater than or equal to the positional deviation of the stop surfaces of adjacent stop elements 16, 18, 20. Here, the positional deviation of the stop surfaces of adjacent stop elements 16, 18, 20 is the positional deviation along the rotational direction of the stop elements 16, 18, 20.

[0051] Furthermore, the third stop element 20 is designed to abut simultaneously against a stop surface of the second stop element 18 and a stop surface of the at least one end stop 22 arranged on the housing 10 of the steer-by-wire system 1 during a rotation of the steering spindle 14 .

[0052] The stop surface of the respective stop element comprises, at least in sections, a metallic stop surface and, at least in sections, a stop damping element 30 , in particular composed of an elastomer.

[0053] The respective stop elements 16 , 18 , 20 are further designed to bring the respective stop damping elements into contact with one another initially when the stop surfaces of the stop elements 16 , 18 , 20 arranged adjacent to one another come into abutment.

Claims

1. A steer-by-wire system (1) for a motor vehicle, comprising a device (12) for mechanically limiting the rotational travel of a steering shaft (14) which is arranged at least partially in sections in a housing (10) of the steer-by-wire system (1), the device comprising a plurality of stop elements (16, 18) rotatably arranged on the steering shaft (14), each of the stop elements comprising: an annular section (16a, 18a) through which the steering shaft (14) is guided; a first stop surface (16b, 18b) extending radially from the annular section (16a, 18a); and a second stop surface (16c, 18c) arranged opposite the first stop surface (16b, 18b). in, A first stop element (16) is connected to the steering shaft (14) in a rotationally fixed manner. wherein at least one second stop element (18) is arranged adjacent to the first stop element (16) in the axial direction of the steering shaft (14), The stop elements (16, 18) are each designed such that the stop surfaces of the stop elements (16, 18) arranged adjacent to each other abut against each other when the steering shaft (14) is rotated, and At least one end stop (22) is arranged on the housing (10) of the steer-by-wire system (1), and the end stop is configured to limit the rotation of the steering shaft (14) in two rotational directions by abutting the stop element (18) arranged adjacent to the end stop (22). The holes (16a1, 18a1) of the corresponding annular sections (16a, 18a) of the first stop element (16) and at least one second stop element (18) have a predetermined gap (24) relative to the steering shaft (14), and the gap is designed to allow the first stop surface (16b, 18b) of the corresponding stop element (16, 18) and the second stop surface (16c, 18c) arranged opposite to each other to abut simultaneously against the stop surface of the adjacent stop element (16, 18).

2. The steer-by-wire system according to claim 1, wherein: A third stop element (20) is arranged adjacent to the at least one second stop element (18), wherein the end stop (22) is configured to limit the rotation of the steering shaft (14) in two rotational directions by abutting the third stop element (20).

3. A steer-by-wire system according to any one of the preceding claims, wherein: The first stop element (16), the at least one second stop element (18), and the third stop element (20) are configured to form a force pair when torque is introduced by the first stop surface (16b, 18b, 20b) and the second stop surface (16c, 18c, 20c) abutting against corresponding stop surfaces of the adjacent stop elements (16, 18, 20).

4. A steer-by-wire system according to any one of the preceding claims, wherein: The first stop element (16), the at least one second stop element (18), and the third stop element (20) are designed to limit the rotational travel of the steering shaft (14) when no transverse force is introduced into the steering shaft (14).

5. A steer-by-wire system according to any one of the preceding claims, wherein: The gap (24) is formed by a diameter difference between the shaft diameter of the steering shaft (14) and the diameter of the hole (16a1, 18a1, 20a1) of the corresponding stop element (16, 18, 20).

6. A steer-by-wire system according to any one of the preceding claims, wherein: The first stop element (16), the at least one second stop element (18) and the third stop element (20) are configured to be aligned relative to the steering shaft (14) when the first stop surface (16b, 18b, 20b) and the second stop surface (16c, 18c, 20c) abut against the corresponding stop surface of the adjacent stop element (16, 18, 20) so that a uniform force transmission can be performed from the first stop surface (16b, 18b, 20b) and the second stop surface (16c, 18c, 20c) to the corresponding stop surface of the adjacent stop element (16, 18, 20).

7. A steer-by-wire system according to any one of the preceding claims, wherein: The size of the gap (24) between the first stop element (16), the at least one second stop element (18) and the third stop element (20) relative to the steering shaft (14) is substantially greater than or equal to the positional deviation (32) of the stop surfaces of the adjacent stop elements (16, 18, 20).

8. The steer-by-wire system according to claim 7, wherein: The positional deviation (32) of the stop surfaces of the adjacent stop elements (16, 18, 20) is a positional deviation along the rotational direction of the stop elements (16, 18, 20).

9. A steer-by-wire system according to any one of the preceding claims, wherein: The third stop element (20) is configured to cause the first stop surface (16b, 18b, 20b) to abut against the first stop surface (16b, 18b, 20b) of the adjacently arranged second stop element (18) when the steering shaft (14) is rotated in a first rotational direction, and wherein the second stop surface (16c, 18c, 20c) abuts against a third stop surface (26) of at least one end stop (22) arranged on the housing (10) of the steer-by-wire system (1).

10. A steer-by-wire system according to any one of the preceding claims, wherein: The third stop element (20) is configured to cause the first stop surface (16b, 18b, 20b) to abut against a second stop surface (16c, 18c, 20c) of the adjacently arranged second stop element (18) when the steering shaft (14) is rotated in a second rotational direction opposite to the first rotational direction, and wherein the second stop surface (16c, 18c, 20c) abuts against a fourth stop surface (28) of at least one end stop (22) arranged on a housing (10) of the steer-by-wire system (1).

11. A steer-by-wire system according to any one of the preceding claims, wherein: The third stop element (20) is configured to simultaneously abut against a stop surface of the second stop element (18) and a stop surface of at least one end stop (22) arranged on the housing (10) of the steer-by-wire system (1) when the steering shaft (14) is rotated.

12. Steer-by-wire system (1) according to any one of the preceding claims, wherein The stop surface of the respective stop element (16, 18, 20) comprises a metallic stop surface at least in sections and a stop buffer element (30) which is in particular composed of an elastomer at least in sections.

13. The steer-by-wire system according to claim 12, wherein: The corresponding stop elements (16, 18, 20) are configured to first bring the corresponding stop buffer elements (30) into contact with each other when the stop surfaces of the stop elements (16, 18, 20) arranged adjacent to each other abut.

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