Pulley systems for vehicle power steering systems

Abstract

The present application discloses a pulley system for a vehicle power steering system. The pulley assembly for a steering assembly includes a motor disposed in a motor housing and having a motor shaft extending from the motor. The pulley assembly also includes a motor panel having a motor guide member extending from the motor panel in the same direction as the direction in which the motor shaft extends away from the motor, and the motor shaft extends through a hole in the motor panel. The pulley assembly also includes an idler pulley column protruding from the motor housing and passing through the motor panel in a direction substantially the same as the axial direction of the motor shaft, and the idler pulley column radially offset from the motor shaft. The pulley assembly also includes a housing flange having a guide hole to accommodate at least a portion of the motor guide and the idler pulley column.

Description

Technical Field

[0001] The following description relates to a vehicle power steering system, and more particularly, to a pulley system for use in such applications. Background Art

[0002] An idler includes a pulley that does not transmit power but guides or tensions the belt. The pulley can rotate around an axis and rests against or presses on the drive belt to guide it or take up slack. In vehicle applications, an idler pulley can be used as part of a pulley assembly of a vehicle to help regulate how the belt runs from the motor shaft to generate motion in other parts and engine accessories. Thus, the belt can rest against an idler pulley as well as other pulleys. An idler pulley can be operably arranged between a drive pulley and a driven pulley. Typically, an idler post connected to or forming an idler pulley is located inside the rack housing. Summary of the invention

[0003] According to one aspect of the present disclosure, a pulley assembly for a steering assembly includes a motor disposed within a motor housing and having a motor shaft extending from the motor. The pulley assembly also includes a motor faceplate having a motor guide extending from the motor faceplate in the same direction as the direction in which the motor shaft extends away from the motor, the motor shaft extending through a hole in the motor faceplate. The pulley assembly also includes an idler pulley post protruding from the motor housing and through the motor faceplate in a direction substantially the same as the axial direction of the motor shaft, the idler pulley post radially offset from the motor shaft. The pulley assembly also includes a housing flange having a guide hole to accommodate at least a portion of the motor guide and the idler pulley post.

[0004] According to another aspect of the present disclosure, a pulley assembly for a steering assembly includes a motor having a motor shaft extending therefrom. The pulley assembly also includes an idler pulley post protruding from the motor in a direction substantially the same as an axial direction of the motor shaft, the idler pulley post being radially offset from the motor shaft. The pulley assembly also includes a housing flange having a guide hole to accommodate at least a portion of the motor guide and the idler pulley post.

[0005] 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

[0006] 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:

[0007] Figure 1 is a perspective view of a pulley system for a vehicle power steering system; and

[0008] Figure 2 A motor assembly housing for a pulley system. DETAILED DESCRIPTION

[0009] Referring now to the accompanying drawings, in which embodiments will be described but not limited, Figure 1 and Figure 2 A pulley system 10 for a vehicle power steering system is shown. The pulley system 10 includes a motor (not shown) disposed within a motor housing 12. The motor may be an electric motor and may include a motor stator and a motor rotor. In one embodiment, the motor may be a DC permanent magnet motor and a motor rotation sensor is fixed to the motor.

[0010] In the illustrated embodiment, the motor housing 12 is substantially cylindrical as defined by a circumferential outer surface 14 extending axially from a first end 16 to a second end 18. The first end 16 has a radial seal 20 and a motor panel 22 operatively connected to the radial seal. A motor shaft 24 extends axially away from the motor and through the motor panel 22. The motor shaft 24 is rotated by the motor and rotates a drive pulley 26 operatively coupled to the motor shaft 24. The motor shaft 24 is positioned by a bearing set.

[0011] The motor housing 12 also includes an idler post 28 that extends away from the motor and through the motor panel 22 in the same direction as the motor shaft 24, but radially offset from the motor shaft 24 (i.e., substantially parallel to the motor shaft 24). Thus, the idler post 28 is integrally formed with the motor or motor housing. The idler post 28 has an idler pulley 30 operably connected to the idler post 28 using an attachment screw 29. The idler pulley 30 is arranged to tension a belt 32 that contacts the drive pulley 26, the idler pulley 30, and a driven pulley 34.

[0012] The motor housing 12 is secured to the housing flange 52 using a plurality of mechanical fasteners 40, such as screws, bolts, etc. In some embodiments, the housing flange 52 shown is only partially shown. The housing flange 52 is a flange / motor interface 52. The housing flange 52 is combined with (e.g., operably coupled to) a housing hereinafter referred to as a rack housing. The entire rack housing houses a toothed rack that engages with a pinion. In other embodiments, the housing flange 52 may be part of a belt / pulley cover, which may be referred to as an auxiliary cover.

[0013] The illustrated embodiment includes three mechanical fasteners 40, however, an alternate number of mechanical fasteners 40 may be employed. The housing flange 52 includes a corresponding number of fastener receiving slots 42 for receiving therethrough the mechanical fasteners 40. The motor housing 12 is aligned relative to the housing flange 52, and therefore relative to the entire housing, thereby assembling the motor housing 12 to the entire housing when the motor guide 60 is inserted into the guide receiving feature (e.g., guide hole) of the housing flange 52.

[0014] The slot 42 may have an arcuate shape and a certain length. As shown, each mechanical fastener 40 includes a shank extending through the slot 42 and into a corresponding receiving aperture 44 in the motor housing 12. The shank includes threads that cooperate with threads in the receiving aperture in the motor housing 12 so that the mechanical fastener 40 can be screwed into the receiving aperture 44. The shank has a diameter that is less than the length of the slot 42. The mechanical fastener 40 can be partially screwed out of the receiving aperture 44 to allow relative rotational movement between the rack housing and the motor housing 12. If the rotation of the motor housing is attempted through the shank, the rotational movement of the motor housing 12 is limited by the length of the receiving slot 42 because the end of the receiving slot 42 is adjacent to the shank of the mechanical fastener 40.

[0015] Because motor housing 12 carries idler post 28, idler pulley 30 can rotate (move / translate) no further than the length of slot 42. Once the desired position of idler pulley 30 is selected, mechanical fasteners 40 can secure motor housing 12 to housing flange 52 at any position within slot 42 for adjusting the contact pressure of idler pulley 30 on belt 32, thereby adjusting the tension of belt 32 as necessary.

[0016] After the motor is installed into the housing flange 52 along with a portion of the motor housing 12 including the idler pulley 30 and the motor shaft 24, the belt 32 is installed and caused to travel around the drive pulley 26 and the driven pulley 34. The motor is then rotated, forcing the idler pulley 30 into the belt 32 to constrain the entire belt to be taut.

[0017] The above-described embodiments may be incorporated into many different applications, such as, but not limited to, vehicle applications including electronic power steering systems and electronic brake boost systems.

[0018] 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. Rather, the present invention may be modified to include any number of variations, changes, substitutions, or equivalent arrangements not previously described but commensurate with the spirit and scope of the present invention. In addition, although various embodiments of the present invention have been described, it should be understood that various aspects 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 pulley assembly for a steering assembly, comprising: a motor disposed within the motor housing and having a motor shaft extending from the motor; a motor panel having a motor guide member extending from the motor panel in the same direction as the motor shaft extends away from the motor, the motor shaft extending through a hole in the motor panel; an idler pulley post projecting from the motor housing and through the motor panel in a direction substantially the same as the axial direction of the motor shaft, the idler pulley post being radially offset from the motor shaft; and a housing flange having a guide hole for receiving at least a portion of the motor guide member and the idler pulley column, the housing flange being located outside the motor housing and combined with the rack housing, the guide hole receiving at least a portion of the motor guide member and the idler pulley column for assembling the motor housing to the rack housing; in The idler pulley column is integrally formed with the motor housing, and has an idler pulley disposed on an end of the idler pulley column, the idler pulley having a diameter greater than a diameter of the idler pulley column.

2. The pulley assembly according to claim 1, wherein: The motor shaft has a drive pulley disposed on an end of the motor shaft.

3. The pulley assembly according to claim 2, wherein: Rotation of the motor and the idler pulley post tensions the pulley belt to a predetermined tension.

4. The pulley assembly according to claim 2, wherein: The pulley assembly is disposed in a vehicle power steering assist system.

5. The pulley assembly according to claim 4, wherein: The vehicle power steering assist system is a part of the electronic power steering system.

6. The pulley assembly according to claim 4, wherein: The vehicle power steering assist system is part of a brake boost actuator.

7. A pulley assembly for a steering assembly, comprising: a motor having a motor housing and a motor shaft extending from the motor; a motor panel having a motor guide member; an idler pulley post projecting from the motor in a direction substantially the same as the axial direction of the motor shaft, the idler pulley post being radially offset from the motor shaft; and a housing flange having a guide hole for receiving at least a portion of the motor guide member and the idler pulley column, the housing flange being located outside the motor housing and combined with the rack housing, the guide hole receiving at least a portion of the motor guide member and the idler pulley column for assembling the motor housing to the rack housing; in The idler pulley column is integrally formed with the motor, the idler pulley column having an idler pulley disposed on an end of the idler pulley column, the idler pulley having a diameter greater than a diameter of the idler pulley column.

8. The pulley assembly according to claim 7, wherein: The motor guide member extends from the motor panel in the same direction as the motor shaft extends away from the motor, the motor shaft extending through a hole in the motor panel.

9. The pulley assembly according to claim 7, wherein: The motor shaft has a drive pulley disposed on an end of the motor shaft.

10. The pulley assembly according to claim 9, wherein: Rotation of the motor and the idler pulley post tensions the pulley belt to a predetermined tension.

11. The pulley assembly according to claim 9, wherein: The pulley assembly is disposed in a vehicle power steering assist system.

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