CN116892599A - Anti-rotation device for a vehicle steering system - Google Patents

Abstract

The present application relates to an anti-rotation device for a vehicle steering system. A linear translation assembly includes a housing. The linear translation assembly further includes a linear translation member movable in an axial direction, wherein at least a portion of a length of the linear translation member is disposed within the housing. The linear translation assembly further includes an anti-rotation device. The anti-rotation device includes a clam-shell assembly that at least partially surrounds the linear translation member in an installed position of the linear translation member. The anti-rotation device also includes an outer clamshell component at least partially surrounding the inner clamshell component. An anti-rotation device is disposed within the housing and axially fixed to the linear translation member at the mounting location in a non-rotational manner relative to the linear translation member, wherein interaction between the anti-rotation device and the housing prevents rotation of the linear translation member.

Description

Anti-rotation device for a vehicle steering system

Cross Reference to Related Applications

The present application claims priority from U.S. provisional patent application Ser. No. 63/326,160, filed on 3 months of 2022, 31, and U.S. provisional patent application Ser. No. 63/330,084, filed on 4 months of 2022, 12, the disclosures of which are incorporated herein by reference in their entirety.

Technical Field

The present application relates to an anti-rotation device for a vehicle steering system.

Background

Various Electric Power Steering (EPS) systems have been developed for assisting an operator in steering a vehicle. One type of EPS system is known as a Rack Electric Power Steering (REPS) system. The REPS system utilizes an electric motor to drive a ball nut and a rack. The rack teeth mesh with a pinion (pinion). The pinion gear supplements a drive feature that rotates in response to rotation of a portion of the steering column by an operator, wherein the drive feature provides steering input to the rack. For example, the drive feature may be integrally formed with the steering column (i.e., a single pinion electric power steering system) or may be a drive pinion (i.e., a dual pinion electric power steering system). During development of a steer-by-wire gear system, OEMs may be interested in removing pinion gears to better facilitate packaging and cost.

In addition to the REPS system discussed above, a Column EPS (CEPS) system was also analyzed to obtain potential improvements in terms of packaging and cost.

Disclosure of Invention

According to one aspect of the present disclosure, a linear translation assembly includes a housing. The linear translation assembly further includes a linear translation member movable in an axial direction, wherein at least a portion of a length of the linear translation member is disposed within the housing. The linear translation assembly further includes an anti-rotation device. The anti-rotation device includes a clam-shell assembly at least partially surrounding the linear translation member at the mounting location of the linear translation member. The anti-rotation device also includes an outer clamshell component at least partially surrounding the inner clamshell component. An 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 interaction between the anti-rotation device and the housing prevents rotation of the linear translation member.

According to another aspect of the present disclosure, an anti-rotation device for a linear translating member includes a clam-shell assembly at least partially surrounding the linear translating member at a mounting location of the linear translating member, wherein the clam-shell assembly includes a first clam-shell element and a second clam-shell element. The anti-rotation device further includes an outer clamshell component at least partially surrounding the inner clamshell component, wherein the outer clamshell component includes a first outer clamshell element and a second outer clamshell element, each surrounding a portion of the inner clamshell component. The anti-rotation device further includes at least one spring element disposed between the inner and outer clamshell components for disengaging the anti-rotation device (de-lash).

According to another aspect of the present disclosure, a steer-by-wire system for a vehicle includes a housing. The steer-by-wire system further includes a ball screw (ball screw) movable in an axial direction and disposed at least partially within the housing. The steer-by-wire system further includes an anti-rotation device disposed proximate an outer surface of the ball screw at the mounting portion thereof, wherein the anti-rotation device has at least one split (split) to define a plurality of segments of the anti-rotation device that are flexible relative to each other, the anti-rotation device being axially and rotationally fixed relative to the ball screw, the ball screw having a non-circular outer surface to interact with the housing in a non-rotatable manner. The steer-by-wire system further includes a biasing element in contact with the anti-rotation device for biasing the plurality of segments radially outwardly.

These and other advantages and features will become more apparent from the following description taken in conjunction with the accompanying drawings.

Drawings

The subject matter which is regarded as the application is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the application are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a steering assembly having an electric power steering assist system;

FIG. 2 is a perspective view of a portion of an electric power steering system having a housing surrounding a linear translation member;

FIG. 3 is a perspective view of the electric power steering system with a portion of the housing removed to show a sleeve of the anti-rotation device;

FIG. 4 is a perspective view of a sleeve and linear translation member of the anti-rotation device;

FIG. 5 is a perspective view of the anti-rotation device in an assembled state with a portion of the sleeve removed;

FIG. 6 is a perspective view of the anti-rotation device in a disassembled state;

FIG. 7 is a perspective view of the anti-rotation device in an assembled state with the sleeve removed;

FIG. 8 is a cross-sectional end view of an anti-rotation device assembled within a housing of an electric power steering system;

FIG. 9 is a perspective view of a linear translation member having knurled sections (knurred sections);

FIG. 10 is a perspective view of an anti-rotation device for the linear translation member of FIG. 9 according to another aspect of the present disclosure;

FIG. 11 is a perspective view of an anti-rotation device according to another aspect of the present disclosure; and

fig. 12 is an end view of the anti-rotation device of fig. 11.

Detailed Description

Referring now to the drawings, the embodiments described herein are used in conjunction with a steering assembly of a vehicle, such as an automobile, truck, sport utility vehicle, cross-car (cross), minivan, watercraft, aircraft, all-terrain vehicle, recreational vehicle, or other suitable vehicle, including various steering system solutions. As discussed herein, electric Power Steering (EPS) systems (including steer-by-wire systems) include, for example, anti-rotation devices without the use of pinions in the steering system. The anti-rotation device resists rotation of the linear translation member. Such rotation is caused by the load of an actuating member (e.g., a thread such as a ball nut) in contact with the linear translating member.

Referring first to FIG. 1, a power steering system 20 is generally shown. The power steering system 20 may be configured as a driver interface steering system, an autonomous driving system, or a system that allows both driver interface and autonomous steering. The steering system may include an input device 22, such as a steering wheel, wherein the driver may mechanically provide steering input by turning the steering wheel. The steering column 26 extends along an axis from the input device 22 to the output assembly 28. The steering column 26 may include at least two axially adjustable components, such as a first sheath (jack) 30 and a second sheath 32, which are axially adjustable relative to each other. The embodiments disclosed herein are used in a steering system (e.g., steer-by-wire, autonomous system, etc.) in operative communication with an actuator 34 coupled to a linear translating member 40 of an output assembly 28. 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.

The linear translating member 40 is any member having a generally cylindrical cross section along at least a portion of its length and is driven in a substantially linear manner to effect adjustment of the vehicle wheel 49. In some embodiments, the linear translation member 40 is a ball screw. In other embodiments, the linear translation member 40 is a lead screw. The foregoing examples are not limiting of the linear translation member 40.

In previous steer-by-wire systems, a pinion gear was utilized on an outer surface of the linear translating member 40 (e.g., a "rack") to provide steering input control of the linear translating member 40 and anti-rotation reaction forces on the linear translating member 40. However, in some steering systems, pinion gears and associated required components (e.g., pinion up and down bearings, rack bearings, adjuster pins, lower rotor and rack teeth, etc.) may be undesirable, for example, based on packaging requirements, cost, and manufacturing complexity considerations. The embodiments of the anti-rotation device disclosed herein provide the previously required anti-rotation advantages of a pinion while eliminating many of the components described above. In the steer-by-wire system, the above-mentioned steering input control of the linear translation member 40 with the pinion is unnecessary.

While the embodiments disclosed herein are described in connection with an EPS system located at the lower/front portion of a steering column and system, it is to be understood that EPS systems that provide assistance at other column locations may also benefit from embodiments of the present disclosure. In particular, column EPS (CEPS) systems can utilize embodiments disclosed herein. Furthermore, the anti-rotation devices disclosed herein may be used in any system that relies on a substantially cylindrical component that is driven in a translational manner and that requires or would benefit from rotation limitation.

Referring to fig. 2, the linear translation member 40 is shown in more detail within the housing 42. Fig. 3 shows a portion of the housing 42 removed, while fig. 4 shows the entire housing 42 removed. The removal of the housing 42 shows an anti-rotation device sleeve 44. The anti-rotation device sleeve 44 surrounds an anti-rotation device 50 (fig. 5-8), as described in detail herein. Since the anti-rotation device 50 is fixed to the linear translation member 40 in a manner that causes the anti-rotation device 50 to translate with the linear translation member 40, the anti-rotation device 50 translates relative to the inner surface of the housing 42, the sleeve 44 acts 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 sleeve inner surface and the anti-rotation device 50 translating therein. The low friction inner surface may be created by the material of the sleeve 44 itself and/or by a coating disposed on the sleeve 44.

Referring now to fig. 5-7, an anti-rotation device 50 is shown. The anti-rotation device 50 is formed of multiple pieces and is mounted on the linear translation member 40 at a mounting location 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 best shown in the exploded view of fig. 6. The embodiments disclosed herein provide the required anti-rotational kinematics to offset the load on the linear translation member while still allowing standard inner and outer tie rods to be used.

Clam-shell assembly 52 includes a first clam-shell element 58 and a second clam-shell element 60. In some embodiments, first and second inner clamshell elements 58, 60 may each be substantially hemispherical with respect to linear translating member 40, such that they each surround about half of linear translating member 40. However, the specific geometry of first and second inner clamshell elements 58, 60 may be different in other embodiments. The mounting location 51 of the linear translation member 40 has a non-threaded portion with at least one protrusion and/or recess 62 that corresponds to at least one recess and/or protrusion 64 of the inner clamshell assembly 52. Specifically, inner surface 68 of clam-shell assembly 52 includes a geometry that interacts with the geometry of mounting location 51 to fix the axial and rotational positions of clam-shell assembly 52 relative to linear translation member 40. In other words, inner clamshell assembly 52 and linear translating member 40 do not rotate or move axially relative to one another.

The outer clamshell assembly 54 includes a first outer clamshell element 70 and a second outer clamshell element 72. The first outer clamshell element 70 and the second outer clamshell element 72 each include a substantially curved inner surface 74. The outer clamshell elements 70, 72 each include an outer surface 76 that does not form a circular arc. Specifically, each outer surface 76 includes a pair of flat portions 78, although slight curvatures are also contemplated. Each outer clamshell element 70, 72 also extends from a first axial end 80 to a second axial end 82, with each axial end extending radially inward to retain the inner clamshell assembly 52 axially therein.

A first spring element slot 84 is defined in the inner surface 74 proximate the first axial end 80 of the outer clamshell elements 70, 72, and a second spring element slot 86 is defined in the inner surface 74 proximate the second axial end 82 of the outer clamshell elements 70, 72. Further, a third spring element slot 85 is defined in the outer surface proximate a first axial end of the inner clam-shell elements 58, 60, and a fourth spring element slot 87 is defined in the outer surface proximate a second axial end of the inner clam-shell elements 58, 60. Each spring element slot 84-87 is sized and positioned to receive a respective spring element therein. Specifically, a first spring element 88 is positioned within the first spring element slot 84 and the third spring element slot 85, and a second spring element 90 is positioned within the second spring element slot 86 and the fourth spring element slot 87. The arrangement of spring elements 88, 90 between inner and outer clamshell assemblies 52, 54 decouples the assemblies relative to one another. In the illustrated embodiment, the spring elements 88, 90 are O-rings. Alternatively, the spring elements 88, 90 may be leaf springs, coil springs, or any other biasing element suitable for the particular use.

The outer surface of first inner clamshell element 58 and/or second inner clamshell element 60 includes at least one protrusion and/or recess 92 that corresponds to at least one recess and/or protrusion 94 of outer clamshell assembly 54. Specifically, inner surface 74 of outer clamshell assembly 54 includes a geometry that interacts with the geometry of inner clamshell assembly 52 to fix the axial and rotational positions of outer clamshell assembly 54 relative to inner clamshell assembly 52. In other words, outer clamshell assembly 54 and inner clamshell assembly 52 do not rotate or move axially relative to each other.

As shown in fig. 5, 7 and 8, in the assembled state of the anti-rotation device 50, the outer clamshell assembly 54, as well as the inner clamshell assembly 52 and the spring elements 88, 90, are positioned within the anti-rotation device sleeve 44. As explained in detail above, the outer clamshell elements 70, 72 each include an outer surface 76 that does not form an arc. Thus, 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 sleeve 44 is also not formed with a circular cross-section, so the contact between outer clamshell assembly 54 and sleeve 44 resists the torque and rotation of anti-rotation device 50, and thus resists the rotation of linear translating member 40. However, during operation and relative to the sleeve 44, the anti-rotation device 50 translates with the linear translation member 40.

It is to be understood that some embodiments do not include a sleeve 44. In such an embodiment, the anti-rotation device 50 interacts directly with the housing 42. The inner surface of the housing 42 geometrically corresponds to the outer clamshell assembly 54 such that rotation and torque of the anti-rotation device 50 is directly resisted by the housing 42.

While the overall exterior geometry of the outer clam-shell assembly 54, sleeve 44 and the interior surface of housing 42 are shown in a substantially square or rectangular configuration, it should be understood that alternative non-circular geometries may be employed as long as rotation and torque are resisted.

Referring to fig. 9 and 10, a linear translating member, generally indicated at 140, is shown in accordance with another aspect of the present disclosure. An anti-rotation device is shown in accordance with another aspect of the present disclosure and is generally designated by reference numeral 150. The axial center of the linear translation member 140 includes a knurled portion 152 and relief grooves (relief grooves). The sleeve 44 is assembled into the housing 42 (fig. 2) to act as a wear and sliding surface to react rotational torque as the linear translating member moves axially in the system, but as described above in connection with other embodiments, the anti-rotation device 150 may interact directly with the inner surface of the housing 42. Rectangular member 154 is pressed against knurled portion 152 and is disengaged from set screw 156 after installation in housing 42, allowing accurate placement of each system.

Referring to fig. 11 and 12, an anti-rotation device is shown in accordance with another aspect of the present disclosure and is generally indicated by reference numeral 250. The anti-rotation device 250 is pressed on at one end 252 against a knurled portion of the linear translation member and includes a steel snap ring 254 or the like mounted on the inside diameter of the other split end 254 to provide an outward force to disengage the system, thereby completing the load transfer path. The anti-rotation device 250 may also be used as a support bushing for screw bending, if desired. The sleeve 44 is assembled into the housing 42 (fig. 2) to act as a wear and sliding surface to react rotational torque as the linear translating member moves axially in the system, but as described above in connection with other embodiments, the anti-rotation device 250 may interact directly with the inner surface of the housing 42.

The embodiments disclosed herein allow for a reduction in packaging space required for EPS systems due to the removal of several components, including the pinion, pinion upper and lower bearings, rack bearings, regulator plug, lower rotor, and rack in the case of REPS systems. Furthermore, the costs and complexity associated with the manufacture and assembly of the overall system are reduced by the anti-rotation devices 50, 150, 250 disclosed herein. Further, embodiments disclosed herein utilize an adjustable non-cylindrical component as an anti-rotation device on a linear translation component, such as a ball screw, lead screw, or other component that facilitates or is required to resist torque and rotation. This is also coupled with mating wear parts to meet NVH and friction requirements.

While the application has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the application is not limited to such disclosed embodiments. Rather, the application can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the application. Further, while various embodiments of the application have been described above, it should be understood that various aspects of the application may include only some of the above-described embodiments. Accordingly, the application is not to be seen as limited by the foregoing description.

Claims (20)

1. A linear translation assembly comprising:

a housing;

a linear translation member movable in an axial direction, wherein at least a portion of a length of the linear translation member is disposed within the housing; and

an anti-rotation device, the anti-rotation device comprising:

a clam-shell assembly at least partially surrounding the linear translation member at a mounting location of the linear translation member; and

an outer clamshell component at least partially surrounding the inner clamshell component,

wherein 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 an interaction between the anti-rotation device and the housing prevents rotation of the linear translation member.

2. The linear translation assembly of claim 1, further comprising a sleeve disposed between the outer clamshell assembly and the housing.

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

4. The linear translation assembly of claim 1, wherein the linear translation member is a ball screw.

5. The linear translation assembly of claim 1, wherein the linear translation component is a lead screw.

6. The linear translation assembly of claim 1, further comprising at least one spring element disposed between the inner and outer clam-shell assemblies to disengage the anti-rotation device.

7. The linear translation assembly of claim 6, wherein the at least one spring element comprises a first spring element and a second spring element, wherein the first spring element is disposed within a third spring slot proximate a first axial end of the inner clamshell assembly and a first spring slot proximate a first axial end of the outer clamshell assembly, wherein the second spring element is disposed within a fourth spring slot proximate a second axial end of the inner clamshell assembly and a second spring slot proximate a second axial end of the outer clamshell assembly.

8. The linear translation assembly of claim 6, wherein the at least one spring element is one of an O-ring, a leaf spring, and a coil spring.

9. The linear translation assembly of claim 1, wherein the clam-shell assembly comprises a first clam-shell element and a second clam-shell element each surrounding a portion of the linear translation component at the mounting location.

10. The linear translation assembly of claim 9, wherein at least one of the first and second clam-shell elements comprises at least one protrusion and/or recess, wherein the mounting position of the linear translation component comprises at least one protrusion and/or recess that engages with the protrusion and/or recess of the first and second clam-shell elements, thereby securing the linear translation component and the clam-shell assembly relative to each other in axial and rotational directions.

11. The linear translation assembly of claim 1, wherein the outer clamshell assembly comprises a first outer clamshell element and a second outer clamshell element, each surrounding a portion of the inner clamshell assembly.

12. The linear translation assembly of claim 11, wherein at least one of the first outer clamshell element and the second outer clamshell element comprises at least one protrusion and/or recess, wherein the inner clamshell element comprises at least one protrusion and/or recess that engages with the protrusion and/or recess of the first outer clamshell element and the second outer clamshell element, thereby securing the outer clamshell element and the inner clamshell element relative to each other in an axial and rotational direction.

13. The linear translation assembly of claim 1, wherein the linear translation assembly is part of an electric power steering system.

14. An anti-rotation device for a linear translation member, comprising:

a clam-shell assembly at least partially surrounding the linear translation member at a mounting location of the linear translation member, wherein the clam-shell assembly comprises a first clam-shell element and a second clam-shell element;

an outer clamshell component at least partially surrounding the inner clamshell component, wherein the outer clamshell component comprises a first outer clamshell element and a second outer clamshell element, each surrounding a portion of the inner clamshell component; and

at least one spring element is disposed between the inner and outer clamshell assemblies for disengaging the anti-rotation device.

15. The anti-rotation device of claim 14, further comprising a sleeve disposed between the outer clamshell assembly and a surrounding housing.

16. The anti-rotation device of claim 14, wherein the at least one spring element comprises a first spring element and a second spring element, wherein the first spring element is disposed within a third spring slot proximate a first axial end of the inner clamshell component and a first spring slot proximate a first axial end of the outer clamshell component, wherein the second spring element is disposed within a fourth spring slot proximate a second axial end of the inner clamshell component and a second spring slot proximate a second axial end of the outer clamshell component.

17. The anti-rotation device of claim 14, wherein the at least one spring element is one of an O-ring, a leaf spring, and a coil spring.

18. A steer-by-wire system for a vehicle, comprising:

a housing;

a ball screw movable in an axial direction and at least partially disposed within the housing; and

an anti-rotation device disposed proximate an outer surface of the ball screw at a mounting portion thereof, wherein the anti-rotation device has at least one split to define a plurality of segments of the anti-rotation device that are flexible relative to one another, the anti-rotation device being axially and rotationally fixed relative to the ball screw, the ball screw having a non-circular outer surface to non-rotatably interact with the housing;

a biasing element is in contact with the anti-rotation device to bias the plurality of segments radially outward.

19. The steer-by-wire system of claim 18, wherein the ball screw has a knurled portion at a mounting location where the anti-rotation device is mounted.

20. The steer-by-wire system of claim 18, wherein the ball screw comprises a knurled outer surface at the mounting portion, the anti-rotation device having a plurality of segments joined by at least one flexible joint, the anti-rotation device having at least one retaining ring disposed within an inner surface of the plurality of segments.