A mechanical limiting device for a steer-by-wire column and a vehicle steering system

Abstract

The application discloses a mechanical limiting device for a steer-by-wire column, which comprises a sleeve, a rotating shaft, a limiting nut, a guide mechanism and a limiting mechanism, wherein the rotating shaft comprises an input shaft and a shaft sleeve, the input shaft extends into the sleeve, the shaft sleeve is fixed to the input shaft, and a first thread is arranged on the outer wall of the shaft sleeve; the inner cavity wall of the limiting nut is provided with a second thread which is screw-connected with the first thread; the guide mechanism comprises a guide block arranged on the outer wall of the limiting nut and a guide groove arranged on the inner wall of the sleeve; and the limiting mechanism comprises a first limiting part and a second limiting part which are arranged at the two ends of the first thread. In the field of automobile steering mechanisms, the mechanical hard limiting of the steer-by-wire column is solved, the mechanical hard limiting is used as the redundant protection of the electric soft limiting, the steering column can be limited even in the power-off state of the vehicle, the rotation of the steering column is ensured to be within the stroke, and the limiting device has the advantages of compact structure, simple arrangement and strong universality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile steering mechanism, in particular to a mechanical limiting device for steer-by-wire steering column and a vehicle steering system. BACKGROUND

[0002] Automobiles are widely used in people's life, and the vehicle steering system is an important part of the automobile. We know that the steering wheel of the vehicle is limited in both clockwise and counterclockwise rotation, such as Figure 1 The traditional vehicle steering system is shown in FIG. 1, the steering column 20 connected below the steering wheel is connected with the steering gear 18 by a universal intermediate shaft 19. Since the steering gear 18 itself is designed with a limiting measure, the steering column 20 does not need to be designed with a limiting device. The gear rack of the steering gear 18 is limited, and at the same time, the steering column 20 will also be limited due to the hard connection of the universal intermediate shaft 19, so the steering wheel will also be limited, and when the steering wheel is limited to the limit, it will be restricted.

[0003] However, the connection mode of the universal intermediate shaft 19 occupies a large space, and it needs to avoid other parts on the whole vehicle to prevent mutual contact and friction between the parts. For example Figure 2 The steer-by-wire vehicle steering system is shown in FIG. 2, which cancels the universal intermediate shaft 19, which means that the arrangement of the steer-by-wire steering column 20A will no longer be limited by the universal intermediate shaft 19, and the arrangement will become more flexible. Therefore, the vehicle steering system of the medium and high-grade passenger car adopts the steer-by-wire vehicle steering system, and this will become a trend, but the problems that follow will also come one after another.

[0004] Since the steer-by-wire vehicle steering system adopts the steer-by-wire steering column 20A, it uses the steer-by-wire cable 21 to transmit electrical signals to control the steering gear 18, and no longer needs the universal intermediate shaft 19, which makes the original limiting function of the steering gear 18 unable to act on the steer-by-wire steering column 20A through the universal intermediate shaft 19. Although the steer-by-wire vehicle steering system is designed with a controller electrical soft limit, when the vehicle fails or is powered off, the steering wheel will continue to rotate beyond the designed range due to the failure of the controller electrical soft limit, resulting in a large angle deviation between the steer-by-wire steering column 20A and the steering gear 18, which makes the steering gear 18 misinterpret the rotation of the steering wheel, thereby causing danger during vehicle driving. SUMMARY

[0005] The purpose of the present application is to provide a mechanical limiting device for steer-by-wire steering column and a vehicle steering system, which can be very conveniently integrated at the bottom of the steering column of the improved vehicle steering system, and is provided with mechanical limiting structures in both clockwise and counterclockwise directions of the steering column, so that the steering wheel will not rotate beyond the range, thereby ensuring the safety of vehicle driving.

[0006] To achieve the above object, the application provides the following technical scheme: a mechanical limiting device for a steer-by-wire column, comprising at least: a sleeve fixedly arranged; a rotating shaft coaxial with the sleeve and capable of rotating relative to the sleeve via a bearing, the rotating shaft comprising an input shaft extending into the sleeve and a shaft sleeve fixedly sleeved on the input shaft, an outer wall of the shaft sleeve being provided with a first thread; a limiting nut, an inner cavity wall of the limiting nut being provided with a second thread screwing with the first thread; a guide mechanism, the guide mechanism comprising a guide block arranged on an outer wall of the limiting nut and a guide groove arranged on an inner wall of the sleeve, an included angle a between a sliding direction of the guide block in the guide groove and an axial direction of the sleeve being in a range of 0-45°; and a limiting mechanism, the limiting mechanism comprising a first limiting part and a second limiting part at two ends of the first thread.

[0007] The shaft sleeve rotates with the input shaft, the guide block on the outer wall of the limiting nut is limited to slide in the guide groove, the first thread and the second thread screw, the limiting nut generates linear feed in the axial direction with the rotation of the rotating shaft, when the feed reaches the first limiting part or the second limiting part, the limiting nut cannot feed any more, and the rotating shaft cannot rotate any more. Thus, one rotation direction of the steering column is mechanically limited, and the other rotation direction of the steering column can also be mechanically limited. The limiting device is a mechanical hard limiting structure, and is compact, simple and easy to arrange. Even in a power-off state of the vehicle, the limiting device can limit the rotation of the steering column in two directions, so as to ensure that the rotation of the steering column does not exceed the stroke. In addition, the limiting device has high universality, and the limiting number can be changed by changing the length of the shaft sleeve and the limiting nut, so as to adapt to different types of vehicles.

[0008] Preferably, the first thread and the second thread are trapezoidal screw threads. The trapezoidal screw threads have long service life and high transmission efficiency, and are suitable for low-speed transmission of the steering column.

[0009] Preferably, the second limiting part is provided with a protective cover fixedly connected with the sleeve on a side opposite to the first thread. The protective cover prevents dust and impurities from entering the limiting device, and effectively protects the internal components.

[0010] Preferably, the protective cover is made of plastic. The weight of the protective cover is further reduced, and the production cost is also reduced.

[0011] Preferably, an outer wall of one end of the shaft sleeve fixed with the input shaft is provided with a third thread, an inner cavity wall of the shaft sleeve is provided with a fourth thread adaptedly connected with the third thread, one end of the shaft sleeve contacts the bearing, and the other end of the shaft sleeve is provided with a locking nut screwedly connected with the input shaft. The shaft sleeve is screwedly connected with the input shaft, the shaft sleeve is axially positioned via the bearing and the locking nut, and the installation is very convenient.

[0012] Preferably, the first limiting part is integrally formed with the shaft sleeve, and the locking nut is the second limiting part.

[0013] Preferably, an annular groove is arranged on the end face of the connecting end of the protective cover, and a sealing ring is arranged in the annular groove.

[0014] Preferably, the included angle alpha between the sliding direction of the guide block in the guide groove and the axial direction of the sleeve is 0°.

[0015] A vehicle steering system at least comprises a steer-by-wire column, a steering gear, a steer-by-wire cable connecting the steer-by-wire column and the steering gear, and a mechanical limiting device for the steer-by-wire column arranged at the bottom of the steer-by-wire column.

[0016] Compared with the prior art, the present application has the following advantages:

[0017] 1. The present limiting device is a mechanical hard limiting structure, and has a compact structure and is easy to arrange.

[0018] 2. The present limiting device has strong versatility, and can be adapted to different types of vehicles by changing the length of the shaft sleeve and the limiting nut to change the number of limiting rings.

[0019] 3. The shaft sleeve is threadedly connected to the input shaft, and the shaft sleeve is axially positioned by the bearing and the locking nut, so that the installation is very simple and reliable.

[0020] 4. The first limiting part is integrally formed with the shaft sleeve, and the locking nut is directly used as the second limiting part.

[0021] 5. The first thread and the second thread are trapezoidal screw threads.

[0022] 6. The protective cover is arranged to prevent dust and other impurities from entering the limiting device, effectively protecting the internal parts.

[0023] 7. The end face of the pipe sleeve and the connecting end of the protective cover is provided with an annular groove, and a sealing ring is arranged in the annular groove. The sealing ring plays a role of grease sealing, so that the lubricating grease of the limiting device cannot leak out, thereby not needing to add lubricating grease for a long time.

[0024] 8. The limiting device has low production cost. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a perspective structural schematic view of a vehicle steering system shown in the prior art;

[0026] Figure 2 It is a perspective structural schematic view of another vehicle steering system shown in the prior art;

[0027] Figure 3 It is a perspective structural schematic view of a vehicle steering system shown in the embodiment;

[0028] Figure 4 It is a perspective structural schematic view of a steer-by-wire column of a vehicle steering system shown in the embodiment, to which a mechanical limiting device is additionally provided;

[0029] Figure 5 It is an enlarged view of Figure 4

[0030] Figure 6 It is a perspective structural schematic view of a pipe sleeve in the mechanical limiting device of the steer-by-wire column shown in the embodiment;

[0031] Figure 7 It is a perspective structural schematic view of a limiting nut in the mechanical limiting device of the steer-by-wire column shown in the embodiment;

[0032] Figure 8 It is a sectional view of the pipe sleeve in the mechanical limiting device of the steer-by-wire column shown in the embodiment.

[0033] In the figure: input shaft 1, shaft sleeve 2, first thread 3, limiting nut 4, second thread 5, pipe sleeve 6, guide block 7, guide groove 8, third thread 9, bearing 10, fourth thread 11, first limiting part 12, second limiting part 13, locking nut 14, protective cover 15, annular groove 16, sealing ring 17, steering gear 18, universal intermediate shaft 19, steering column 20, steer-by-wire cable 21, rotating shaft 22, steer-by-wire column 20A. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present application by specific examples, and other advantages and effects of the present application can be easily understood by those skilled in the art according to the content disclosed in the specification.

[0035] ​It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effectiveness and purpose of this invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0036] like Figures 4-8 As shown, a mechanical limiting device for a steering column in this embodiment includes at least: a sleeve 6, which is fixedly installed; a rotating shaft 22, which is coaxial with the sleeve 6 via a bearing 10 and can rotate relative to the sleeve 6, with at least a portion of the rotating shaft 22 extending into the sleeve 6, and a first thread 3 on the rotating shaft 22 extending into the sleeve 6; a limiting nut 4, the inner wall of which is provided with a second thread 5 that screws into the first thread 3; a guiding mechanism, which includes a guide block 7 disposed on the outer wall of the limiting nut 4 and a guide groove 8 disposed on the inner wall of the sleeve 6, the angle α between the sliding direction of the guide block 7 in the guide groove 8 and the axial direction of the sleeve 6 being in the range of 0 to 45°; and a limiting mechanism, which includes a first limiting part 12 and a second limiting part 13 located at both ends of the first thread 3, such that when the limiting nut 4 is fed to the first limiting part 12 or the second limiting part 13, the limiting nut 4 can no longer be fed in the same direction.

[0037] Preferably, the first thread 3 and the second thread 5 are trapezoidal lead screw threads, which have high transmission efficiency and excellent transmission accuracy, making them suitable for low-speed transmission of the steering column by wire. The second limiting part 13 has a protective cover 15 fixedly connected to the sleeve 6 on the side opposite to the first thread 3. The protective cover 15 is preferably made of plastic.

[0038] Preferably, the rotating shaft 22 may include an input shaft 1 and a bushing 2 that is sleeved and fixed to the input shaft 1. A first thread 3 is provided on the outer wall of the bushing 2, making the machining of the first thread 3 more convenient. Preferably, a third thread 9 is provided on the outer wall of one end of the input shaft 1 that fixes the bushing 2, and a fourth thread 11 that is adapted to and connected to the third thread 9 is provided on the inner wall of the bushing 2. One end of the bushing 2 contacts the bearing 10, and the other end of the bushing 2 is provided with a locking nut 14 that is threaded and fixed to the input shaft 1.

[0039] As preferred, the first limiting part 12 is integrally formed with the shaft sleeve 2, and the locking nut 14 is the second limiting part 13. Of course, the first limiting part 12 and the second limiting part 13 can also be provided as separate components. The end face of the pipe sleeve 6 at the connecting end of the protective cover 15 is provided with an annular groove 16, and the annular groove 16 is provided with a sealing ring 17. The included angle a between the sliding direction of the guide block 7 in the guide groove 8 and the axial direction of the pipe sleeve 6 is preferably 0°, at which time the axial linear feeding efficiency of the limiting nut is the highest, and the directional limiting force is the largest.

[0040] As Figure 3 A vehicle steering system is shown, which at least comprises a steer-by-wire column 20A, a steering gear 18, and a steer-by-wire cable 21 connecting the steer-by-wire column 20A and the steering gear 18, and further comprises the above-mentioned steer-by-wire column mechanical limiting device arranged at the bottom of the steer-by-wire column 20A, and the rotating shaft 22 is coaxially connected with the steer-by-wire column 20A.

[0041] Working principle: when the steering wheel is turned in one direction, the input shaft 1 and the shaft sleeve 2 are also turned, and since the guide block 7 of the limiting nut 4 is limited in the guide groove 8, the relative rotation of the first thread 3 and the second thread 5 causes the guide block 7 to slide in the guide groove 8 to produce axial displacement, until the limiting nut 4 hits the first limiting part 12 or the second limiting part 13 and cannot move any more, at which time the steering wheel in this direction is locked and can only be turned in the opposite direction. Similarly, when the limiting nut 4 hits the second limiting part 13 or the first limiting part 12 in the opposite direction, the opposite direction is also locked, so that the steering wheel is limited in two directions, and this limiting is a mechanical hard limiting. Of course, under normal circumstances, the mechanical hard limiting will not be used, and it is a redundant protection of the electrical soft limiting.

[0042] As described above, the present application provides a steer-by-wire column mechanical limiting device, which is a mechanical hard limiting structure, and the structure is compact, simple and easy to arrange. Even in the case of power loss of the vehicle, the limiting device can still limit the rotation of the steer-by-wire column in two directions, thereby ensuring that the rotation of the steer-by-wire column will not exceed the stroke. The limiting device has strong universality, and the number of limiting rings can be changed by changing the length of the shaft sleeve and the limiting nut, thereby adapting to different types of vehicles. The first thread and the second thread are trapezoidal screw threads, which have a long service life, high transmission efficiency, and excellent transmission accuracy, and are suitable for low-speed transmission of the steer-by-wire column. The protective cover is provided to effectively protect the internal components.

[0043] The above embodiments are only illustrative of the principles of the present application and its efficacy, and are not intended to limit the present application. Any modification or change made by any person skilled in the art without departing from the spirit and scope of the present application shall be covered by the claims of the present application.

Claims

1. A mechanical limiting device for a steer-by-wire column, characterized in that, At least including: Tube sleeve (6), the tube sleeve (6) is fixedly installed; A rotating shaft (22) is coaxial with the sleeve (6) via a bearing (10) and can rotate relative to the sleeve (6). The rotating shaft (22) includes at least a portion of an input shaft (1) that extends into the sleeve (6) and a bushing (2) that is sleeved and fixed to the input shaft (1). The outer wall of the bushing (2) is provided with a first thread (3). The limiting nut (4) has a second thread (5) that is helically engaged with the first thread (3) on its inner wall; the first thread (3) and the second thread (5) are trapezoidal screw threads. The guiding mechanism includes a guide block (7) disposed on the outer wall of the limiting nut (4) and a guide groove (8) disposed on the inner wall of the sleeve (6). The angle α between the sliding direction of the guide block (7) in the guide groove (8) and the axial direction of the sleeve (6) is in the range of 0~45°. The limiting mechanism includes a first limiting part (12) and a second limiting part (13) located at both ends of the first thread (3), wherein the first limiting part (12) is integrally formed with the bushing (2); The input shaft (1) has a third thread (9) on the outer wall of one end of the bushing (2), and a fourth thread (11) that is adapted to and connected to the third thread (9) is provided on the inner wall of the bushing (2). One end of the bushing (2) contacts the bearing (10), and the other end of the bushing (2) is provided with a locking nut (14) that is threaded to the input shaft (1). The locking nut (14) is the second limiting part (13).

2. The mechanical limiting device for the steering column according to claim 1, characterized in that, The second limiting part (13) is provided with a protective cover (15) on the side opposite to the first thread (3) and fixedly connected to the sleeve (6).

3. The mechanical limiting device for the steering column according to claim 2, characterized in that, The protective cover (15) is made of plastic.

4. The mechanical limiting device for the steering column according to claim 2, characterized in that, The end face of the connection between the sleeve (6) and the protective cover (15) is provided with an annular groove (16), and a sealing ring (17) is provided in the annular groove (16).

5. The mechanical limiting device for the steering column according to claim 1, characterized in that, The angle α between the sliding direction of the guide block (7) in the guide groove (8) and the axial direction of the sleeve (6) is 0°.

6. A vehicle steering system, comprising at least a steering column (20A), a steering gear (18), and a steering cable (21) connecting the steering column (20A) and the steering gear (18), characterized in that, It also includes a mechanical limiting device for the steer-by-wire column as described in any one of claims 1-5, located at the bottom of the steer-by-wire column (20A), wherein the rotating shaft (22) is coaxially connected to the steer-by-wire column (20A).

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