Slope snap ring for rack type electric power steering system

Abstract

The invention relates to a ramp snap ring for a rack-and-rack electric power steering system. A vehicle steering assembly includes a rack translatable and disposed within a rack housing, the rack configured to be operably coupled with a pair of walking wheels. The vehicle steering assembly also includes a pinion shaft operably coupled with the rack. The vehicle steering assembly also includes a bearing in contact with the pinion shaft and disposed within the rack housing. The vehicle steering assembly also includes a snap ring partially disposed within a groove defined by the rack housing, the snap ring in contact with the bearing in a first state, the snap ring having an ear defining a bore, where the snap ring is movable from the first state pressing the bearing to hold the bearing in place to a second state in which the snap ring is movable from the first state to the second state. The second state allows the bearing to be removed from the pinion shaft.

Description

Technical Field

[0001] The present disclosure relates to an electric power steering system for a vehicle, and more particularly, to a ramp snap ring for a rack-type electric power steering system. Background Art

[0002] An electric power steering (EPS) system is used to supplement the steering torque input applied by the operator of the vehicle to the steering wheel of the vehicle. The EPS system has a controller (e.g., an electronic control unit) that calculates the required assist force based on the steering torque input, the steering wheel position, and the vehicle speed. The EPS system also has an electric motor that uses the calculated assist force to rotate a steering gear to control the vehicle steering operation, thereby providing an improved steering experience for the operator.

[0003] The lower rotor assembly of the EPS system includes a lower rotor and a probe housing assembly (PHA). The PHA may include a plastic component and a printed circuit board (PCB) coupled to the plastic component. The lower rotor is coupled to a pinion shaft assembly in a rack-and-pinion EPS configuration, and the pinion shaft assembly is at least partially guided by a bearing. A retaining ring is provided to hold the bearing in place within the rack housing. However, because the retaining ring is located below the lower rotor and the PHA, it is difficult to remove the pinion shaft assembly from the rack-and-pinion EPS. Conventional parts arrangements leave little or no room to remove the retaining ring without damaging the PHA. After the lower rotor and upper rotor are removed from the pinion shaft, the retaining ring can be removed, but after the retaining ring is maintained or replaced, the PHA (and possibly the rotor) must be replaced with a new component. Therefore, there is a need for an assembly that does not require the replacement of additional parts during the disassembly process. Summary of the invention

[0004] According to one embodiment of the present disclosure, a vehicle steering assembly includes a rack that can translate and is disposed in a rack housing, the rack being configured to be operably connected to a pair of road wheels. The vehicle steering assembly also includes a pinion shaft operably connected to the rack. The vehicle steering assembly also includes a bearing that contacts the pinion shaft and is disposed in the rack housing. The vehicle steering assembly also includes a snap ring that is partially disposed in a groove defined by the rack housing, the snap ring contacts the bearing in a first state, the snap ring having an ear portion defining a hole, wherein the snap ring can be moved from a first state to a second state, the first state pressing the bearing to hold the bearing in place, the second state allowing the bearing to be removed from the pinion shaft.

[0005] According to another embodiment of the present disclosure, a vehicle steering assembly includes a rack that is capable of translation and is disposed in a rack housing, the rack being configured to be operably connected to a pair of road wheels. The vehicle steering assembly also includes a pinion shaft operably connected to the rack. The vehicle steering assembly also includes a bearing that contacts the pinion shaft and is disposed in the rack housing. The vehicle steering assembly also includes a snap ring that is partially disposed in a groove defined by the rack housing, the snap ring contacts the bearing in a first state, the snap ring including a ramp portion that contacts an outer race of the bearing.

[0006] These and other advantages and features will become more apparent from the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The subject matter which is regarded as the invention 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 invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0008] Figure 1 is a schematic diagram of a rack-type electric power steering system;

[0009] Figure 2 is a cross-sectional view of a rack-type electric power steering system at the interface of the pinion shaft and the bearing with a snap ring;

[0010] Figure 3 yes Figure 2 an enlarged view of a portion of the bearing showing the interface of the snap ring with the bearing;

[0011] Figure 4 It is a stereogram of the clasp;

[0012] Figure 5 is a cross-sectional view of a rack-type electric power steering system with a retaining ring in an installed position; and

[0013] Figure 6 is a cross-section of a rack-type electric power steering system with the retaining ring opened for removal. DETAILED DESCRIPTION

[0014] Referring now to the drawings, wherein the invention will be described with reference to specific embodiments (but not limited thereto), an electric power steering (EPS) system is disclosed. More specifically, the EPS system includes subassemblies that can be disassembled without the need to replace components.

[0015] The embodiments described herein are used in conjunction with a steering system of a vehicle such as an automobile, truck, sport utility vehicle, crossover, minivan, boat, aircraft, all-terrain vehicle, recreational vehicle, or other suitable vehicle including various steering system solutions.

[0016] First reference Figure 1 , generally showing 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 that allows both driver interface and autonomous steering. The steering system can include an input device 22 (e.g., a steering wheel), wherein a driver can mechanically provide steering input by turning the steering wheel. A steering column 26 extends from the input device 22 to an output assembly 28 along an axis. The steering column 26 includes one or more jackets. The embodiments disclosed herein are used in a steering system, wherein the output assembly 28 is in operative communication with a linear translation component 40, which in some embodiments is a rack. The output assembly 28 is a pinion shaft that contacts the rack 40, and can be referred to as an output assembly or a pinion shaft. The rack 40 pivots the steering wheel 42 to steer the vehicle. One or more sensors detect the angle and torque of the steering column components associated with the steering input provided by the operator. The ECU can receive the sensor input and electronically communicate the assist force to be applied to the rack 40 with the assist mechanism 50 to reduce the steering torque input required by the operator.

[0017] Although the illustrated embodiment shows a rack electric power steering (REPS) system in which electromechanical assistance is provided to a portion of the rack structure, it should be understood that the embodiments disclosed herein may be applicable to steer-by-wire steering systems.

[0018] Figure 2 The lower rotor assembly 60 for a torque sensor according to an embodiment of the present disclosure is shown. The torque sensor may be combined with Figure 1 The torque sensor described above can be used in a REPS system of a vehicle to detect a steering torque input to a steering wheel by an operator of the vehicle. A lower rotor assembly 60 is mounted to the pinion shaft 28. A probe housing assembly 64 houses a probe that detects an electric field or a magnetic field generated during rotation of the lower rotor assembly 60. A bearing 68 contacts a portion of the pinion shaft 28. The lower rotor assembly 60 and the bearing 68 and the shaft 28 are located within a rack housing 70. The bearing 68 is at least partially held in place by a snap ring 72. The snap ring 72 also de-lashes the entire pinion shaft assembly.

[0019] Reference now Figure 3 , showing Figure 2In particular, a portion of the snap ring 72 and the bearing 68 are shown in greater detail. Figure 4 A perspective view of the snap ring 72 is shown to illustrate additional details of the snap ring 72 .

[0020] The snap ring 72 is generally circular with a gap forming a gap between a first end 74 of the snap ring 72 and a second end 76 of the snap ring 72 that defines the length of the snap ring 72. The snap ring 72 extends from a radially inner edge 78 to a radially outer edge 80 to define a radial width of the snap ring 72. The snap ring 72 also extends from a first side 82 to a second side 84 to define a thickness of the snap ring 72. The snap ring 72 has a bevel portion 86 on a second side 84 of the snap ring 72. The bevel portion 86 contacts an outer race 88 of the bearing 68. The contact between the bevel portion 86 and the outer race 88 holds the bearing 68 in place. The bevel portion 86 is an inclined portion that allows the snap ring 72 to press the bearing 68 radially inward and downward / forward in the direction of the vehicle.

[0021] The snap ring 72 includes at least one ear that projects radially outward from the radially outer edge 80 of the snap ring 72. In the illustrated embodiment, a pair of ears are shown, specifically a first ear 90 and a second ear 92. The ears 90, 92 may be formed of various contemplated shapes other than the illustrated geometry. Regardless of the specific geometry, each ear 90, 92 defines a hole 94 that allows a tool to be inserted therein to facilitate manipulation of the snap ring 72 in an installed state. In particular, the snap ring 72 may be moved from a "working" state ( Figure 5 ) is biased radially outward to the "open" position ( Figure 6 ).exist Figure 5 In the operating state, the snap ring 72 presses the bearing 68 radially inward and downward / forward in the direction of the vehicle, as described above. Figure 6 In the open position, the snap ring 72 is manipulated into a position that allows the bearing 68 to be pushed in for installation or pulled out for removal while avoiding damage to other components.

[0022] A portion of the snap ring 72, including the radially outer edge 80, is disposed within a groove 96 defined by the rack housing 70. The groove 96 provides space for the ears 90, 92 and for flexing of the snap ring 72 during the opening process described in detail herein.

[0023] The snap ring 72 disclosed herein allows a tool to open the snap ring 72 in a small space, which avoids scrapping other components during the bearing removal process.

[0024] Although the present invention has been described in detail in conjunction with only a limited number of embodiments, it should be readily understood that the present invention is not limited to these disclosed embodiments. On the contrary, the present invention may be modified to include any number of changes, alterations, substitutions, or equivalent arrangements not previously described but commensurate with the spirit and scope of the present disclosure. In addition, although various embodiments of the present invention have been described, it should be understood that the scheme of the present invention may include only some of the described embodiments. Therefore, the present invention should not be considered to be limited by the foregoing description.

Claims

1. A vehicle steering assembly, comprising: A rack, the rack being translatable and disposed in a rack housing, the rack being configured to be operably coupled to a pair of traveling wheels; a pinion shaft operably coupled to the rack; a bearing, the bearing being in contact with the pinion shaft and being disposed in the rack housing; as well as a snap ring partially disposed within a groove defined by the rack housing, the snap ring contacting the bearing in a first state, the snap ring having an ear defining a hole, wherein the snap ring is movable from the first state, the first state pressing the bearing to hold the bearing in place, to a second state allowing the bearing to be removed from the pinion shaft.

2. The vehicle steering assembly according to claim 1, wherein: The snap ring includes a sloped surface portion that contacts an outer ring of the bearing.

3. The vehicle steering assembly according to claim 1, wherein: The ear portion is a first ear portion and the collar further includes a second ear portion.

4. The vehicle steering assembly according to claim 2, wherein: The snap ring is generally circular.

5. The vehicle steering assembly according to claim 4, wherein: The collar extends from a first end to a second end to define a length of the collar.

6. The vehicle steering assembly according to claim 4, wherein: The snap ring extends from a radially inner edge to a radially outer edge to define a radial width of the snap ring.

7. The vehicle steering assembly according to claim 4, wherein: The collar extends from the first side to the second side to define a thickness of the collar.

8. The vehicle steering assembly according to claim 7, wherein: The beveled portion of the snap ring is located on the second side of the snap ring.

9. A vehicle steering assembly, comprising: A rack, the rack being translatable and disposed in a rack housing, the rack being configured to be operably coupled to a pair of traveling wheels; a pinion shaft operably coupled to the rack; a bearing, the bearing being in contact with the pinion shaft and being disposed in the rack housing; as well as A snap ring is partially disposed in a groove defined by the rack housing, the snap ring contacts the bearing in a first state, and the snap ring includes a sloped surface portion that contacts an outer ring of the bearing.

10. The vehicle steering assembly according to claim 9, wherein: The snap ring is generally circular.

11. The vehicle steering assembly according to claim 10, wherein: The collar extends from a first end to a second end to define a length of the collar.

12. The vehicle steering assembly of claim 10, wherein: The snap ring extends from a radially inner edge to a radially outer edge to define a radial width of the snap ring.

13. The vehicle steering assembly of claim 10, wherein: The collar extends from the first side to the second side to define a thickness of the collar.

14. The vehicle steering assembly of claim 13, wherein: The beveled portion of the snap ring is located on the second side of the snap ring.

15. The vehicle steering assembly of claim 9, wherein: The snap ring includes an ear defining a hole, wherein the snap ring is movable from a first state, the first state compressing the bearing to hold the bearing in place, to a second state allowing the bearing to be removed from the pinion shaft.

16. The vehicle steering assembly of claim 15, wherein: The ear portion is a first ear portion and the collar further includes a second ear portion.

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