A hard stop module for a steering column and a steer-by-wire device

Abstract

The application relates to the field of steering gears, and particularly discloses a hard-limiting module for a steering column and a steer-by-wire device. The hard-limiting module comprises a base, a driving wheel and a driven wheel, the driving wheel and the driven wheel are respectively rotationally connected with the base, a part of the driving wheel in the circumferential direction is provided with driving teeth, a part of the driven wheel in the circumferential direction is provided with driven teeth, a limiting mechanism is further included, the limiting mechanism is used for limiting the rotation angle range of the driven wheel, a pressing mechanism is further included, the pressing mechanism comprises a pressing unit and a plurality of positioning grooves, the pressing unit comprises a pressing block and an elastic piece, one of the pressing block and the positioning grooves is arranged on the driven wheel, and the other is arranged on the base, and the pressing block is transferred between adjacent positioning grooves along with the rotation of the driven wheel. The hard-limiting module has the advantages of small volume and reliable operation.

Description

Technical Field

[0001] This invention relates to the field of steering systems, and more particularly to a hard limit module for a steering column and a steer-by-wire device. Background Technology

[0002] The steering system is an important component of a car, mainly consisting of the steering column, steering wheel, and steering gear, used to control the car's direction of travel.

[0003] In most common steering systems, the range of adjustment angles is typically limited. For example, the number of steering wheel rotations is limited; many cars limit the steering wheel rotation in one direction to three full rotations (one and a half rotations to the left and right). In typical steering systems, the steering column is connected to the steering gear via an intermediate shaft. Since the steering gear itself has a limiting mechanism, this limiting mechanism can, in turn, limit the number of steering wheel rotations.

[0004] With the development of the automotive industry, steer-by-wire systems will become a trend in the future. However, in steer-by-wire systems, there is no intermediate shaft between the steering column and the steering gear, meaning it's impossible to limit the number of steering wheel rotations by using the steering gear in the reverse direction. To address this problem, the commonly used solution is to use a software control system to automatically identify the number of steering wheel rotations and then limit the rotation through external power—a technique known as soft limiting. However, software control systems are prone to failure, making the limiting effect unreliable.

[0005] Chinese invention patent CN 109455219B discloses a steering wheel limiting method for a steer-by-wire system, including a gear limiting mechanism. The gear limiting mechanism includes a pinion, a semi-circular gear, and a limiting shaft. The pinion is fixed on the steering column and meshes with the semi-circular gear. When the pinion rotates a preset number of turns with the steering column, the semi-circular gear contacts the limiting shaft and cannot continue to rotate, thus achieving hard limiting.

[0006] However, in the aforementioned steering wheel limiting method for steer-by-wire systems, when the allowed number of steering wheel rotations is large, the size of the semi-circular gear becomes very large. For example, taking four steering wheel rotations as an example, the diameter of the semi-circular gear should be at least eight times that of the pinion; otherwise, the pinion will separate from the semi-circular gear, losing its rotation limiting function. Furthermore, in automobiles, due to the complexity of the structure and the limited space for the installation and movement of the gear limiting mechanism, the aforementioned steering wheel limiting method for steer-by-wire systems is difficult to widely implement in various types of vehicles. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a hard limit module for steering column and a steer-by-wire device, which has the advantages of small size and reliable operation.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a hard limit module for a steering column, comprising a base, a drive wheel and a driven wheel, wherein the drive wheel and the driven wheel are rotatably connected to the base;

[0009] The drive wheel has drive teeth in a portion of the circumferential direction;

[0010] It also includes a limiting mechanism, which is used to limit the rotation angle range of the driven wheel;

[0011] It also includes a clamping mechanism, which includes a clamping unit and several positioning slots. The clamping unit includes a clamping block and an elastic element. One of the clamping block and the positioning slot is disposed on the driven wheel, and the other is disposed on the base. As the driven wheel rotates, the clamping block moves between adjacent positioning slots.

[0012] During operation, there are two states between the driving and driven teeth as the driving wheel rotates: in the meshing state, the driven wheel rotates synchronously with the driving wheel; in the disengaged state, the driven wheel is stationary.

[0013] The driving gear partially covers the driven gear in the circumferential direction. During the rotation of the driving gear, the driving and driven gears are not always meshed, but exist in two states: meshing and disengagement. In the meshing state, the driven gear rotates synchronously with the driving gear; in the disengagement state, the driven gear remains stationary. While ensuring the number of rotations of the driving gear, the rotation angle range of the driven gear can be reduced, thereby reducing the size of the driven gear and the overall space occupied by the hard limit module.

[0014] The clamping mechanism is used to restrain the driven wheel in a specific position, ensuring the stability of the driven wheel's position when stationary, thereby guaranteeing the transmission accuracy between the driving wheel and the driven wheel and ensuring good operational reliability. When the driving wheel drives the driven wheel to rotate, the clamping block moves between adjacent positioning slots.

[0015] Preferably, the limiting mechanism includes a limiting pin disposed on the base; the driven wheel is provided with a limiting groove arranged in an arc around the axis, and the limiting pin is inserted into the limiting groove.

[0016] During the rotation of the driven wheel, the limiting pin moves relative to the limiting groove along the extension direction of the limiting groove. When the driven wheel rotates to the limit angle, the limiting pin makes hard contact with the end of the limiting groove, thereby limiting the rotation angle of the driven wheel.

[0017] Preferably, the driven wheel has driven teeth in a portion of the circumferential region;

[0018] The limiting mechanism includes two limiting posts set on the base. The minimum distance between the outer side of the limiting post and the root circle of the driven tooth is Y. The tooth height of the driven tooth is H. Then Y < H.

[0019] Along the circumferential direction of the driven wheel, a limiting interval is formed between the two limiting posts, and the driven tooth is disposed within the limiting interval and moves within the range of the limiting interval.

[0020] The driven teeth are distributed only in a portion of the circumference of the driven wheel. When the driven wheel moves to its limit angle under the drive of the driving wheel, the driven teeth make hard contact with the limiting post. The rotation angle of the driven wheel is limited by the structural strength of the driven teeth and the limiting post themselves.

[0021] Preferably, the driving teeth are continuously distributed on the driving wheel, and the driven teeth are continuously distributed on the driven wheel;

[0022] If the number of driving teeth on the driving wheel is A and the number of driven teeth on the driven wheel is B, then B > (A+1)*S, where S is the preset number of rotations of the corresponding steering wheel.

[0023] By properly setting the number of driving and driven teeth, precise control over the number of steering wheel rotations can be achieved.

[0024] Preferably, the central angle corresponding to each driven tooth is α, the central angle corresponding to the limiting interval is β, the number of driving teeth on the driving wheel is A, and the preset number of rotations of the steering wheel is S.

[0025] Then we have β=B×α+[(A+1)×α]+f,

[0026] Where f is the rotational margin, f = 0.5° to 1°.

[0027] By appropriately setting the angle of the limit range, precise control of the number of steering wheel rotations can be achieved. When the soft limit function of the built-in software control system of the steer-by-wire device is working properly, the setting of the rotation margin can effectively avoid interference between the hard limit system and the soft limit system. In other words, it ensures that the hard limit module will only take effect if the soft limit system fails.

[0028] As a preferred option, Y = 0.2~0.3H. This ensures sufficient movement space between the driven wheel and the limiting post, while also providing adequate contact space between the driven tooth and the limiting post, thus reasonably balancing motion performance and strength performance.

[0029] Preferably, the positioning groove is provided on the circumferential side of the driven wheel and is staggered from the driven teeth in the circumferential direction;

[0030] The clamping block is connected to the base via an elastic element.

[0031] Preferably, the system also includes a protective cover, which is detachably connected to the base, and the driven gear is located inside the protective cover; the clamping unit is connected to the inner wall of the protective cover.

[0032] The protective cover can provide some protection for the driven gear and the meshing structure between the driven gear and the driving gear, and also provides conditions for the installation of the clamping mechanism.

[0033] A steer-by-wire device includes a column and a steering wheel, and also includes a hard limit module as described above, wherein the drive wheel is connected to the column and rotates synchronously.

[0034] The hard limit module of this application can be directly added to existing steer-by-wire devices in a modular form, which has good adaptability and is ready for widespread use.

[0035] Preferably, the system also includes a deceleration mechanism, the housing of which serves as the base of the hard limit module. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the hard-limiting module for the steering column according to the first embodiment of the present invention; at this time, the driving gear and the driven gear are in a meshing state;

[0037] Figure 2 This is a schematic diagram of the hard limiting module for the steering column according to the first embodiment of the present invention; at this time, the driven tooth and the limiting post are in contact.

[0038] Figure 3 This is a schematic diagram of the hard-limiting module for the steering column according to the first embodiment of the present invention; at this time, the driving gear and the driven gear are in a separated state;

[0039] Figure 4 This is a schematic diagram of the interaction between the driven wheel and the limiting column in the hard limiting module for the steering column according to the first embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram of the interaction between the driven wheel and the limiting column of the hard limiting module for the steering column in the first embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of the hard limiting module for the steering column according to the second embodiment of the present invention;

[0042] Figure 7 This is a partial structural schematic diagram of the steer-by-wire device according to the third embodiment of the present invention;

[0043] Figure 8 This is a partial exploded view of the steer-by-wire device according to the third embodiment of the present invention;

[0044] Figure 9This is a schematic diagram of the protective cover in the steering-by-wire device according to the third embodiment of the present invention;

[0045] Figure 10 This is a partial cross-sectional view of the steer-by-wire device according to the third embodiment of the present invention;

[0046] Figure 11 for Figure 10 A magnified view of the area at point X. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0048] Example 1

[0049] like Figures 1-3 As shown, a hard limit module for a steering column includes a base 1, a drive wheel 2, and a driven wheel 3, wherein the drive wheel 2 and the driven wheel 3 are rotatably connected to the base 1.

[0050] like Figures 1-3 As shown, the driving wheel 2 has driving teeth 21 in a portion of its circumferential direction, and the driven wheel 3 has driven teeth 32 in a portion of its circumferential direction; that is, both the driving wheel 21 and the driven wheel 3 are incomplete gears. The driving teeth 21 are continuously distributed on the driving wheel 2, and the driven teeth 32 are continuously distributed on the driven wheel 3. Specifically, if the number of driving teeth 21 on the driving wheel 2 is A, and the number of driven teeth 32 on the driven wheel 3 is B, then B > (A+1)*S, where S is the preset number of rotations of the corresponding steering wheel. By reasonably setting the number of driving teeth 21 and driven teeth 32, precise control of the number of steering wheel rotations can be achieved.

[0051] like Figures 1-3 As shown, it also includes a limiting mechanism, which is used to limit the rotation angle range of the driven wheel 3. Specifically, the limiting mechanism includes two limiting posts 4 disposed on the base 1, such as... Figure 5 As shown, the minimum distance Y between the outer surface of the limiting post 4 and the bottom circle of the driven tooth 32 is given, and the tooth height of the driven tooth 32 is given, so Y < H. A limiting interval is formed between the two limiting posts 4 along the circumferential direction of the driven wheel 3. The driven tooth 32 is positioned within the limiting interval and moves within its range.

[0052] Specifically, Y = 0.2~0.3H. While ensuring sufficient movement space between the driven wheel 3 and the limiting post 4, there is also sufficient contact space between the driven tooth 32 and the limiting post 4, reasonably balancing motion performance and strength performance.

[0053] like Figure 4 As shown, the central angle corresponding to each driven tooth 32 is α, the central angle corresponding to the limiting interval is β, the number of driving teeth 21 on the driving wheel 2 is A, and the preset number of rotations of the steering wheel is S.

[0054] Then we have β=B×α+[(A+1)×α]+f,

[0055] Where f is the rotational margin, f = 0.5° to 1°.

[0056] By appropriately setting the angle of the limit range, precise control of the number of steering wheel rotations can be achieved. When the soft limit function of the built-in software control system of the steer-by-wire device is working properly, the setting of the rotation margin can effectively avoid interference between the hard limit system and the soft limit system. In other words, it ensures that the hard limit module will only take effect if the soft limit system fails.

[0057] The driven teeth 32 are distributed only in a portion of the circumference of the driven wheel 3. When the driven wheel 3 moves to its limit angle under the drive of the driving wheel 2, the driven teeth 32 make hard contact with the limiting post 4. The rotation angle of the driven wheel 3 is limited by the structural strength of the driven teeth 32 and the limiting post 4.

[0058] During operation, as the driving wheel 2 rotates, there are two states between the driving tooth 21 and the driven tooth 32: in the meshing state, the driven wheel 3 rotates synchronously with the driving wheel 2; in the disengaged state, the driven wheel 3 is stationary.

[0059] The driving tooth 21 partially covers the driven wheel 3 in the circumferential direction. During the rotation of the driving wheel 2, the driving tooth 21 and the driven tooth 32 are not always meshed, but exist in two states: meshing and disengagement. In the meshing state, the driven wheel 3 rotates synchronously with the driving wheel 2; in the disengagement state, the driven wheel 3 remains stationary. When the driven tooth 32 on the driven wheel 3 contacts the limiting post 4, even if the driving wheel 2 still has a tendency to move in the same direction, it cannot continue to move, thus achieving hard limiting. The above-mentioned hard limiting module can reduce the rotation angle range of the driven wheel 3 while ensuring the number of rotations of the driving wheel 2, thereby reducing the size of the driven wheel 3 and reducing the overall space occupied by the hard limiting module.

[0060] like Figures 1-3 As shown, it also includes a clamping mechanism 5, which includes a clamping unit and several positioning grooves 31. The clamping unit includes a clamping block 51 and an elastic element 52. One of the clamping block 51 and the positioning groove 31 is disposed on the driven wheel 3, and the other is disposed on the base 1. As the driven wheel 3 rotates, the clamping block 51 moves between adjacent positioning grooves 31.

[0061] Specifically, such as Figures 1-3As shown, the positioning groove 31 is provided on the circumferential side of the driven wheel 3 and is staggered from the driven tooth 32 in the circumferential direction. The clamping block 51 is connected to the base through the elastic element 52.

[0062] The clamping mechanism 5 is used to restrict the driven wheel 3 to a specific position, ensuring the stability of the driven wheel 3 in a static state, thereby ensuring the transmission accuracy between the driving wheel 2 and the driven wheel 3, and providing excellent operational reliability. When the driving wheel 2 drives the driven wheel 3 to rotate, the clamping block 51 moves between adjacent positioning slots 31.

[0063] Furthermore, such as Figures 7-11 As shown, it also includes a protective cover 6, which is detachably connected to the base 1. The driven gear 32 is located inside the protective cover 6, and the clamping unit is connected to the inner wall of the protective cover 6.

[0064] The protective cover 6 can provide a certain degree of protection for the driven gear 32 and the meshing structure between the driven gear 32 and the driving gear 21, and also provides conditions for the installation of the clamping mechanism 5.

[0065] like Figure 9 As shown, the inner wall of the protective cover 6 is provided with auxiliary support holes 61 that correspond one-to-one with the limiting post 4. The auxiliary support holes 61 can provide auxiliary support and positioning for the free end of the limiting post 4.

[0066] Example 2

[0067] like Figure 6 As shown, compared with Embodiment 1, the difference in this embodiment is that the limiting mechanism includes a limiting pin 34 disposed on the base 1. The driven wheel 3 is provided with a limiting groove 33 arranged in an arc shape θ around the axis, and the limiting pin 34 is inserted into the limiting groove 33. Correspondingly, the positioning groove 31 is disposed on the lower side of the driven wheel 3.

[0068] During the rotation of the driven wheel 3, the limiting pin 34 moves relative to the limiting groove 33 along the extension direction of the limiting groove 33. When the driven wheel 3 rotates to the limit angle, the limiting pin 34 makes hard contact with the end of the limiting groove 33, thereby limiting the rotation angle of the driven wheel 3.

[0069] like Figure 6 As shown, specifically, the central angle corresponding to the arc where the limiting groove 33 is located is θ, then: θ=(A*S)*α+f, where f is the rotation margin, f=0.5°~1°.

[0070] Example 3

[0071] like Figures 7-11As shown, a steer-by-wire device includes a column and a steering wheel, and also includes the hard stop module described above. The drive wheel 2 is connected to the main shaft of the column and rotates synchronously. Specifically, it also includes a reduction mechanism, the housing 7 of which serves as the base 1 of the hard stop module.

[0072] The hard limit module of this application can be directly added to existing steer-by-wire devices in a modular form, which has good adaptability and is ready for widespread use.

[0073] In summary, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hard-limiting module for a steering column, characterized in that: It includes a base, a driving wheel, and a driven wheel, wherein the driving wheel and the driven wheel are rotatably connected to the base; The driving wheel has driving teeth in a portion of its circumferential direction; the driven wheel has driven teeth in a portion of its circumferential direction. It also includes a limiting mechanism, which is used to limit the rotation angle range of the driven wheel; the limiting mechanism includes two limiting posts set on the base, the minimum distance from the outer side of the limiting post to the root circle of the driven tooth is Y, the tooth height of the driven tooth is H, then Y < H; Along the circumference of the driven wheel, a limiting interval is formed between the two limiting posts, and the driven tooth is disposed within the limiting interval and moves within the range of the limiting interval; It also includes a clamping mechanism, which includes a clamping unit and several positioning slots. The clamping unit includes a clamping block and an elastic element. One of the clamping block and the positioning slot is disposed on the driven wheel, and the other is disposed on the base. As the driven wheel rotates, the clamping block moves between adjacent positioning slots. It also includes a protective cover, which is detachably connected to the base, and the driven wheel is located inside the protective cover; the clamping unit is connected to the inner wall of the protective cover; the inner wall of the protective cover is provided with auxiliary support holes corresponding to the limiting posts, which are used to provide auxiliary support for the free end of the limiting posts. During operation, there are two states between the driving and driven teeth as the driving wheel rotates: in the meshing state, the driven wheel rotates synchronously with the driving wheel; in the disengaged state, the driven wheel is stationary.

2. The hard limit module according to claim 1, characterized in that: The limiting mechanism includes a limiting pin disposed on the base; the driven wheel is provided with a limiting groove arranged in an arc around the axis, and the limiting pin is inserted into the limiting groove.

3. The hard limit module according to claim 1, characterized in that: The driving teeth are continuously distributed on the driving wheel, and the driven teeth are continuously distributed on the driven wheel; If the number of driving teeth on the driving wheel is A and the number of driven teeth on the driven wheel is B, then B > (A+1)*S, where S is the preset number of rotations of the corresponding steering wheel.

4. The hard limit module according to claim 1, characterized in that: The central angle corresponding to each driven tooth is α, the central angle corresponding to the limiting interval is β, the number of driving teeth on the driving wheel is A, the number of driven teeth on the driven wheel is B, and the preset number of rotations of the steering wheel is S. Then there is , Where f is the rotational margin, f = 0.5°~1°.

5. The hard limit module according to claim 1, characterized in that: Y = 0.2~0.3H.

6. The hard limit module according to any one of claims 1-5, characterized in that: The positioning groove is provided on the circumferential side of the driven wheel and is staggered from the driven teeth in the circumferential direction; The clamping block is connected to the base via an elastic element.

7. A steer-by-wire device, comprising a column and a steering wheel, characterized in that: It also includes a hard limit module as described in any one of claims 1-6, wherein the drive wheel is connected to the column and rotates synchronously.

8. The steer-by-wire device according to claim 7, characterized in that: It also includes a deceleration mechanism, the housing of which serves as the base of the hard limit module.

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