Anti-rotation device for a vehicle steering system

Abstract

The present application relates to an anti-rotation device for a vehicle steering system. A linear translation assembly comprises a housing. The linear translation assembly further comprises a linear translation component movable in an axial direction, wherein at least a portion of the length of the linear translation component is arranged within the housing. The linear translation assembly further comprises an anti-rotation device. The anti-rotation device comprises an inner shell-like component at least partially surrounding the linear translation component at a mounting position of the linear translation component. The anti-rotation device further comprises an outer shell-like component at least partially surrounding the inner shell-like component. The anti-rotation device is arranged within the housing and axially fixed to the linear translation component in a non-rotational manner relative to the linear translation component at the mounting position, wherein an interaction between the anti-rotation device and the housing prevents rotation of the linear translation component.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 326,160, filed March 31, 2022, and U.S. Provisional Patent Application Serial No. 63 / 330,084, filed April 12, 2022, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0003] This application relates to an anti-rotation device for a vehicle steering system. Background Technology

[0004] Various electric power steering (EPS) systems have been developed to assist operators in steering vehicles. One type of EPS system is called a rack and pinion electric power steering (REPS) system. REPS systems utilize an electric motor to drive a ball nut and a rack. The rack teeth mesh with a pinion. The pinion complements a drive feature that rotates in response to rotation of a portion of the steering column by the operator, providing steering input to the rack. For example, the drive feature can be integrally formed with the steering column (i.e., a single-pinion electric power steering system) or it can be a drive pinion itself (i.e., a dual-pinion electric power steering system). During the development of geared steering systems, OEMs may be interested in removing the pinion for better packaging and cost reduction.

[0005] In addition to the REPS system discussed above, column EPS (CEPS) systems were also analyzed to obtain potential improvements related to packaging and cost. Summary of the Invention

[0006] According to one aspect of this disclosure, a linear translation assembly includes a housing. The linear translation assembly also includes a linear translation member movable in an axial direction, wherein at least a portion of the length of the linear translation member is disposed within the housing. The linear translation assembly also includes an anti-rotation device. The anti-rotation device includes an inner clamshell-shaped assembly that at least partially surrounds the linear translation member at a mounting location. The anti-rotation device also includes an outer clamshell-shaped assembly that at least partially surrounds the inner clamshell-shaped assembly. The anti-rotation device is disposed within the housing and is axially fixed to the linear translation member at the mounting location in a non-rotational manner relative to the linear translation member, wherein the interaction between the anti-rotation device and the housing prevents rotation of the linear translation member.

[0007] According to another aspect of this disclosure, an anti-rotation device for a linear translation component includes an inner clamshell-shaped assembly at least partially surrounding the linear translation component at its mounting location, wherein the inner clamshell-shaped assembly includes a first inner clamshell-shaped element and a second inner clamshell-shaped element. The anti-rotation device also includes an outer clamshell-shaped assembly at least partially surrounding the inner clamshell-shaped assembly, wherein the outer clamshell-shaped assembly includes a first outer clamshell-shaped element and a second outer clamshell-shaped element, each surrounding a portion of the inner clamshell-shaped assembly. The anti-rotation device further includes at least one spring element disposed between the inner and outer clamshell-shaped assemblies for de-lashing the anti-rotation device.

[0008] According to another aspect of this disclosure, a steer-by-wire system for a vehicle includes a housing. The steer-by-wire system also includes a ball screw movable in an axial direction and at least partially disposed within the housing. The steer-by-wire system further includes an anti-rotation device disposed at a mounting portion of the ball screw near its outer surface, wherein the anti-rotation device has at least one split to define a plurality of segments of the anti-rotation device, the plurality of segments being flexible relative to each other, the anti-rotation device being fixed relative to the ball screw in both axial and rotational respects, the ball screw having a non-circular outer surface to interact with the housing in a non-rotatable manner. The steer-by-wire system also includes a biasing element in contact with the anti-rotation device for radially outward biasing of the plurality of segments.

[0009] These and other advantages and features will become more apparent from the following description taken in conjunction with the accompanying drawings. Attached Figure Description

[0010] The subject matter of this invention is specifically pointed out and explicitly claimed in the claims at the end of this specification. The foregoing and other features and advantages of this invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0011] Figure 1 A steering assembly with an electric power steering assist system is shown;

[0012] Figure 2 This is a perspective view of a part of an electric power steering system, showing a housing surrounding a linear translation component;

[0013] Figure 3 This is a perspective view of an electric power steering system, in which a portion of the housing has been removed to show the sleeve of the anti-rotation device.

[0014] Figure 4 It is a three-dimensional view of the sleeve and linear translation component of the anti-rotation device;

[0015] Figure 5 It is a perspective view of the anti-rotation device in its assembled state, with part of the sleeve removed;

[0016] Figure 6 It is a 3D view of the anti-rotation device in a disassembled state;

[0017] Figure 7 This is a perspective view of the anti-rotation device in its assembled state, with the sleeve removed;

[0018] Figure 8 This is a cross-sectional end view of the anti-rotation device assembled inside the housing of the electric power steering system;

[0019] Figure 9 It is a three-dimensional view of a linear translation component with a knurled portion;

[0020] Figure 10 This is a perspective view of an anti-rotation device according to another aspect of this disclosure, used for Figure 9 Linear translation components;

[0021] Figure 11 This is a perspective view of an anti-rotation device according to another aspect of this disclosure; and

[0022] Figure 12 yes Figure 11 End view of the anti-rotation device. Detailed Implementation

[0023] Referring now to the accompanying drawings, the embodiments described herein are used in conjunction with steering components of vehicles such as automobiles, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, recreational vehicles, or other suitable vehicles, which include various steering system options. As discussed herein, electric power steering (EPS) systems (including steer-by-wire systems) that do not use pinions in the steering system include, for example, an anti-rotation device. This anti-rotation device resists rotation of the linear translation component. Such rotation is caused by the load on the actuating component (e.g., the thread of a ball nut) in contact with the linear translation component.

[0024] First refer to Figure 1The diagram generally illustrates a power steering system 20. The power steering system 20 can be configured as a driver-interface steering system, an autonomous driving system, or a system allowing both driver-interface and autonomous steering. The steering system may include an input device 22 (such as a steering wheel) through which the driver mechanically provides steering input by turning the steering wheel. A steering column 26 extends along an axis from the input device 22 to an output assembly 28. The steering column 26 may include at least two axially adjustable components, such as a first jacket 30 and a second jacket 32, which are axially adjustable relative to each other. The embodiments disclosed herein are used in steering systems (e.g., steer-by-wire, autonomous systems, etc.) where the output assembly 28 operatively communicates with an actuator 34 coupled to a linear translation member 40. The output assembly 28 has wired communication 36 with the actuator 34. The actuator 34 drives the linear translation member 40 to provide steering control of the vehicle.

[0025] The linear translation component 40 is any component having a generally cylindrical cross-section along at least a portion of its length and being driven in a substantially linear manner to achieve adjustment of the vehicle wheel 49. In some embodiments, the linear translation component 40 is a ball screw. In other embodiments, the linear translation component 40 is a lead screw. The foregoing examples are not intended to limit the linear translation component 40.

[0026] In previous steer-by-wire systems, a pinion was used on the outer surface of the linear translation member 40 (e.g., a "rack") to provide steering input control for the linear translation member 40 and anti-rotation reaction force on the linear translation member 40. However, due to considerations such as packaging requirements, cost, and manufacturing complexity, the pinion and associated required components (e.g., upper and lower pinion bearings, rack bearings, adjuster plugs, lower rotor, and rack teeth, etc.) may be undesirable in some steering systems. The embodiments of the anti-rotation device disclosed herein provide the anti-rotation advantages of the previously required pinion while eliminating many of the aforementioned components. In steer-by-wire systems, the aforementioned use of a pinion for steering input control of the linear translation member 40 is unnecessary.

[0027] Although the embodiments disclosed herein are described in conjunction with EPS systems located at the lower / front portion of the steering column and system, it is to be understood that EPS systems providing assistance at other column locations can also benefit from the embodiments disclosed herein. In particular, column EPS (CEPS) systems can utilize the embodiments disclosed herein. Furthermore, the anti-rotation devices disclosed herein can be used in any system that relies on a basic cylindrical component driven in a translational manner and requires or would benefit from rotational limitation.

[0028] refer to Figure 2 The linear translation component 40 is shown in more detail inside the housing 42. Figure 3It shows that a portion of the housing 42 has been removed, while Figure 4 The entire housing 42 is shown removed. Removing the housing 42 reveals the anti-rotation device sleeve 44. The anti-rotation device sleeve 44 surrounds the anti-rotation device 50 ( Figures 5-8 As detailed herein, since the anti-rotation device 50 is fixed to the linear translation member 40 in such a way that it translates together with the linear translation member 40, the anti-rotation device 50 translates relative to the inner surface of the housing 42, and the sleeve 44 serves as an intermediate wear surface for the anti-rotation device 50. The anti-rotation device sleeve 44 has a low-friction inner surface to reduce friction between the inner surface of the sleeve and the anti-rotation device 50 translating therein. The low-friction inner surface may be produced by the material of the sleeve 44 itself and / or by a coating disposed on the sleeve 44.

[0029] Now for reference Figures 5-7 An anti-rotation device 50 is shown. The anti-rotation device 50 is formed of multiple parts and is mounted on the linear translation member 40 at a mounting position 51. The anti-rotation device 50 includes an inner clamshell assembly 52, an outer clamshell assembly 54, at least one spring element 88, 90—and in some embodiments, a sleeve 44—as shown in… Figure 6 The exploded view clearly illustrates this. The embodiments disclosed herein provide the necessary anti-rotational kinematics to counteract loads on linear translational components, while still allowing the use of standard inner and outer tie rods.

[0030] The clamshell-shaped assembly 52 includes a first clamshell-shaped element 58 and a second clamshell-shaped element 60. In some embodiments, both the first clamshell-shaped element 58 and the second clamshell-shaped element 60 may be substantially hemispherical relative to the linear translation member 40, such that they each surround approximately half of the linear translation member 40. However, in other embodiments, the specific geometry of the first clamshell-shaped element 58 and the second clamshell-shaped element 60 may differ. The mounting position 51 of the linear translation member 40 has a non-threaded portion having at least one protrusion and / or recess 62 corresponding to at least one recess and / or protrusion 64 of the clamshell-shaped assembly 52. ​​Specifically, the inner surface 68 of the clamshell-shaped assembly 52 includes a geometry that interacts with the geometry of the mounting position 51 to fix the axial and rotational positions of the clamshell-shaped assembly 52 relative to the linear translation member 40. In other words, the clamshell-shaped assembly 52 and the linear translation member 40 do not rotate or move axially relative to each other.

[0031] The outer shell-like assembly 54 includes a first outer shell-like element 70 and a second outer shell-like element 72. Both the first and second outer shell-like elements 70 and 72 include a substantially curved inner surface 74. The outer shell-like elements 70 and 72 each include a non-arc-shaped outer surface 76. Specifically, each outer surface 76 includes a pair of flat portions 78, but a slight curvature may also be considered. Each outer shell-like element 70 and 72 also extends from a first axial end 80 to a second axial end 82, wherein each axial end extends radially inward to axially retain the inner shell-like assembly 52 therein.

[0032] A first spring element groove 84 is defined within the inner surface 74 near the first axial end 80 of the outer clamshell elements 70, 72, and a second spring element groove 86 is defined within the inner surface 74 near the second axial end 82 of the outer clamshell elements 70, 72. Furthermore, a third spring element groove 85 is defined within the outer surface near the first axial end of the inner clamshell elements 58, 60, and a fourth spring element groove 87 is defined within the outer surface near the second axial end of the inner clamshell elements 58, 60. The dimensions and positions of each spring element groove 84-87 are designed to receive a respective spring element therein. Specifically, a first spring element 88 is positioned within the first spring element groove 84 and the third spring element groove 85, and a second spring element 90 is positioned within the second spring element groove 86 and the fourth spring element groove 87. The arrangement of the spring elements 88, 90 between the inner clamshell assembly 52 and the outer clamshell assembly 54 allows the assemblies to disengage relative to each other. In the illustrated embodiment, the spring elements 88, 90 are O-rings. Alternatively, spring elements 88 and 90 may be leaf springs, disc springs, or any other biasing element suitable for a particular application.

[0033] The outer surfaces of the first inner shell-like element 58 and / or the second inner shell-like element 60 include at least one protrusion and / or recess 92, which corresponds to at least one recess and / or protrusion 94 of the outer shell-like assembly 54. Specifically, the inner surface 74 of the outer shell-like assembly 54 includes a geometry that interacts with the geometry of the inner shell-like assembly 52 to fix the axial and rotational positions of the outer shell-like assembly 54 relative to the inner shell-like assembly 52. ​​In other words, the outer shell-like assembly 54 and the inner shell-like assembly 52 will not rotate or move axially relative to each other.

[0034] like Figure 5 , Figure 7 and Figure 8As shown, in the assembled state of the anti-rotation device 50, the outer clamshell assembly 54—along with the inner clamshell assembly 52 and spring elements 88 and 90—is positioned within the anti-rotation device sleeve 44. As explained in detail above, the outer clamshell elements 70 and 72 each include an outer surface 76 that does not form a circular arc. Therefore, in the assembled state, the entire outer surface of the outer clamshell assembly 54 does not form a circle, cylinder, or the like. Similarly, the inner surface of the sleeve 44 does not form a circular cross-section; therefore, the contact between the outer clamshell assembly 54 and the sleeve 44 resists the torque and rotation of the anti-rotation device 50, thereby resisting the rotation of the linear translation member 40. However, during operation and relative to the sleeve 44, the anti-rotation device 50 translates together with the linear translation member 40.

[0035] It should be understood that some embodiments do not include the sleeve 44. In such embodiments, the anti-rotation device 50 interacts directly with the housing 42. The inner surface of the housing 42 corresponds geometrically to the outer clamshell assembly 54, thereby directly resisting the rotation and torque of the anti-rotation device 50 through the housing 42.

[0036] Although the overall external geometry of the inner surfaces of the outer clamshell assembly 54, sleeve 44 and housing 42 is shown in a basically square or rectangular configuration, it should be understood that alternative non-circular geometries may also be used, provided that rotation and torque are resisted.

[0037] Reference Figure 9 and Figure 10 According to another aspect of this disclosure, a linear translation component is shown, generally indicated by reference numeral 140. According to another aspect of this disclosure, an anti-rotation device is shown, generally indicated by reference numeral 150. The axial center of the linear translation component 140 includes a knurled portion 152 and a relief groove. A sleeve 44 is assembled to a housing 42. Figure 2 In the case of linear translation components, the anti-rotation device 150 serves as a wear and sliding surface, thus reacting against the rotational torque as the linear translation components move axially within the system. However, as described above in conjunction with other embodiments, the anti-rotation device 150 can interact directly with the inner surface of the housing 42. The rectangular member 154 is pressed against the knurled portion 152 and disengaged from the retaining screw 156 after installation in the housing 42, thereby allowing for precise setup of each system.

[0038] refer to Figure 11 and Figure 12According to another aspect of this disclosure, an anti-rotation device, generally indicated by reference numeral 250, is shown. The anti-rotation device 250 is pressed at one end 252 against the knurled portion of the linear translation member and includes a steel retaining ring 254 mounted on the inner diameter of the other split end 254 to provide an outward force to disengage the system, thereby completing the load transfer path. If desired, the anti-rotation device 250 can also be used as a support bushing for screw bending. A sleeve 44 is assembled to the housing 42 (…). Figure 2 In the case of linear translation components, the anti-rotation device 250 can act as a wear and sliding surface, thus reacting with the rotational torque when the linear translation components move axially in the system. However, as described above in conjunction with other embodiments, the anti-rotation device 250 can interact directly with the inner surface of the housing 42.

[0039] By removing several components (including the pinion, pinion upper and lower bearings, rack bearing, adjuster plug, lower rotor, and, in the case of a REPS system, rack), the embodiments disclosed herein allow for a reduction in the package space required for the EPS system. Furthermore, the anti-rotation devices 50, 150, and 250 disclosed herein reduce the cost and complexity associated with the manufacture and assembly of the entire system. Additionally, the embodiments disclosed herein utilize adjustable non-cylindrical components as anti-rotation devices on linear translational components, such as ball screws, lead screws, or other components that facilitate resistance to torque and rotation or are necessary to resist torque and rotation. This also connects with mating wear components to meet NVH and friction requirements.

[0040] Although the invention has been described in detail with reference to only a limited number of embodiments, it is readily understood that the invention is not limited to these disclosed embodiments. Instead, the invention can be modified to include any number of variations, alterations, substitutions, or equivalent arrangements not previously described but commensurate with the spirit and scope of the invention. Furthermore, although various embodiments of the invention have been described above, it should be understood that various aspects of the invention may include only some of the embodiments described above. Therefore, the invention should not be considered as limited to the foregoing description.

Claims

1. A linear translation component, comprising: case; A linear translational component movable in an axial direction, wherein at least a portion of the length of the linear translational component is disposed within the housing; as well as Anti-rotation device, the anti-rotation device comprising: An inner clamshell-shaped assembly, at least partially surrounding the linear translation component at its mounting location; and An outer clamshell-like component, at least partially surrounding the inner clamshell-like component. The anti-rotation device is disposed within the housing and is axially fixed to the linear translation component at the mounting position in a non-rotational manner relative to the linear translation component, wherein the interaction between the anti-rotation device and the housing prevents the rotation of the linear translation component; The linear translation component further includes at least one spring element disposed between the inner clamshell component and the outer clamshell component to disengage the anti-rotation device. The inner clamshell-shaped component includes a first inner clamshell-shaped element and a second inner clamshell-shaped element, and the outer clamshell-shaped component includes a first outer clamshell-shaped element and a second outer clamshell-shaped element.

2. The linear translation component according to claim 1 further includes a sleeve disposed between the outer clamshell component and the housing.

3. The linear translation component according to claim 1, wherein, The anti-rotation device and the housing are in direct contact with each other.

4. The linear translation component according to claim 1, wherein, The linear translation component is a ball screw.

5. The linear translation component according to claim 1, wherein, The linear translation component is a lead screw.

6. The linear translation assembly according to claim 1, wherein the at least one spring element comprises a first spring element and a second spring element, wherein the first spring element is disposed in a third spring groove near the first axial end of the inner clamshell assembly and in a first spring groove near the first axial end of the outer clamshell assembly, wherein the second spring element is disposed in a fourth spring groove near the second axial end of the inner clamshell assembly and in a second spring groove near the second axial end of the outer clamshell assembly.

7. The linear translation component according to claim 1, wherein, The at least one spring element is one of an O-ring, a leaf spring, and a disc spring.

8. The linear translation component according to claim 1, wherein, The first and second inner clamshell-shaped elements each surround a portion of the linear translation component at the mounting position.

9. The linear translation component according to claim 8, wherein, At least one of the first and second inner clamshell-shaped elements includes at least one protrusion and / or recess, wherein the mounting position of the linear translation component includes at least one protrusion and / or recess that engages with the protrusion and / or recess of the first and second inner clamshell-shaped elements, thereby fixing the linear translation component and the inner clamshell-shaped assembly relative to each other in both axial and rotational respect.

10. The linear translation component according to claim 1, wherein, The first and second outer clamshell-shaped elements each surround a portion of the inner clamshell-shaped assembly.

11. The linear translation component according to claim 10, wherein, At least one of the first and second outer shell-like elements includes at least one protrusion and / or recess, wherein the inner shell-like assembly includes at least one protrusion and / or recess that engages with the protrusion and / or recess of the first and second outer shell-like elements, thereby fixing the outer shell-like assembly and the inner shell-like assembly relative to each other in terms of axial and rotational aspects.

12. The linear translation component according to claim 1, wherein, The linear translation component is part of the electric power steering system.

13. An anti-rotation device for a linear translation component, comprising: An inner clamshell-shaped assembly at least partially surrounds the linear translation component at the mounting position of the linear translation component, wherein the inner clamshell-shaped assembly includes a first inner clamshell-shaped element and a second inner clamshell-shaped element; An outer shell-like assembly, at least partially surrounding the inner shell-like assembly, wherein the outer shell-like assembly includes a first outer shell-like element and a second outer shell-like element, each of the first and second outer shell-like elements surrounding a portion of the inner shell-like assembly; and At least one spring element is disposed between the inner clamshell assembly and the outer clamshell assembly for disengaging the anti-rotation device.

14. The anti-rotation device according to claim 13, further comprising a sleeve disposed between the outer clamshell assembly and the surrounding shell.

15. The anti-rotation device according to claim 13, wherein, The at least one spring element includes a first spring element and a second spring element, wherein the first spring element is disposed in a third spring groove near the first axial end of the inner clamshell assembly and in a first spring groove near the first axial end of the outer clamshell assembly, wherein the second spring element is disposed in a fourth spring groove near the second axial end of the inner clamshell assembly and in a second spring groove near the second axial end of the outer clamshell assembly.

16. The anti-rotation device according to claim 13, wherein, The at least one spring element is one of an O-ring, a leaf spring, and a disc spring.

17. A steer-by-wire system for a vehicle, comprising: case; A ball screw, which is movable in an axial direction and is at least partially disposed within the housing; as well as An anti-rotation device is provided at the mounting portion of the ball screw near the outer surface of the ball screw, wherein the anti-rotation device has at least one split to define a plurality of segments of the anti-rotation device, the plurality of segments being flexible relative to each other, the anti-rotation device being fixed relative to the ball screw in both axial and rotational aspects, the ball screw having a non-circular outer surface so as to interact with the housing in a non-rotational manner; A biasing element contacts the anti-rotation device to bias the plurality of segments radially outward.

18. The steer-by-wire system according to claim 17, wherein, The ball screw has a knurled portion at the mounting position where the anti-rotation device is installed.

19. The steer-by-wire system according to claim 17, wherein, The ball screw includes a knurled outer surface at the mounting portion, the anti-rotation device has multiple segments joined by at least one flexible joint, and the anti-rotation device has at least one retaining ring disposed within the inner surface of the multiple segments.

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