JP2007137315A - Rack and pinion hydraulic power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rack and pinion hydraulic power steering device capable of inexpensively preventing the generation of abnormal noise. <P>SOLUTION: The rack and pinion hydraulic power steering device 1 comprises: an input shaft 2; an output shaft 4 having a pinion 3; a hydraulic control valve 8 disposed to the circumference of the input shaft 2; a pinion housing 13 surrounding the pinion 3; a valve housing 14 surrounding the hydraulic control valve 8 and connected with the pinion housing 13; and a rolling bearing 36 supporting the output shaft 4 between the pinion 3 and the hydraulic control valve 8. A male screw 46 is formed on the outer peripheral surface 42c of an outer ring 42 of the rolling bearing 36, and a female screw 47 is formed on the inner peripheral surface 16b of a valve housing 14. By screwing the male screw 46 and the female screw 47 to each other, movement in the axial direction Y1 of the output shaft 4 is restricted with respect to the valve housing 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a so-called drop-in rack-and-pinion type hydraulic power steering apparatus.

  For example, in a rack-and-pinion type hydraulic power steering device having a drop-in structure, a tubular valve housing for accommodating a hydraulic control valve is incorporated into a sub assembly by incorporating a hydraulic control valve and a pinion shaft as an output shaft. The subassembly is inserted into the pinion housing (drop-in), and then the valve housing and the pinion housing are connected to complete the assembly operation.

Further, the outer ring of the bearing that supports the pinion shaft is sandwiched in the axial direction by receiving portions respectively provided on the valve housing and the pinion housing. However, there may be a gap in the axial direction between the receiving portion and the outer ring, and the pinion shaft may rattle in the axial direction due to this gap, and there is a risk of generating abnormal noise.
Therefore, it has been proposed to screw the plug into the valve housing so that the outer ring of the bearing is clamped between the receiving portion and the plug to prevent rattling of the pinion shaft in the axial direction (for example, Patent Document 1).
JP 2002-145091 A

However, in the invention described in Patent Document 1, it is necessary to add a plug in order to suppress the shakiness of the pinion shaft in the axial direction, which increases the cost.
The present invention has been made based on such a background, and an object of the present invention is to provide a rack and pinion type hydraulic power steering apparatus that can prevent generation of abnormal noise at low cost.

  In order to achieve the above object, a rack is formed on the input shaft (2) and the output shaft (4) that are coaxially connected to each other via a torsion bar (9) and the outer periphery (2a) of the output shaft. A pinion (3) meshing with the shaft (6), a hydraulic control valve (8) for generating hydraulic pressure according to the relative rotation of the input shaft and the output shaft, and a cylindrical housing (5) surrounding the pinion and the hydraulic control valve ), A rolling bearing (35, 350) that supports the input shaft, and a rolling bearing (36, 37, 360) that supports the output shaft, and a rolling bearing that supports the input shaft and an output shaft. At least one of these includes a predetermined rolling bearing (36, 350), and relative axial movement between the predetermined rolling bearing and the corresponding shaft is restricted. A male screw (46, 460) is formed on the outer peripheral surface (42c, 351a) of the outer ring (42, 351) of the predetermined rolling bearing, and this male screw is formed on the inner peripheral surface (16b, 50b) of the housing. A rack and pinion type hydraulic power steering apparatus, wherein the rack and pinion type hydraulic power steering apparatus is screwed into the formed female thread (47, 470).

According to the present invention, the predetermined rolling bearing is fixed to the housing by screwing the female screw formed on the inner peripheral surface of the housing and the male screw formed on the outer peripheral surface of the outer ring of the predetermined rolling bearing. Yes. Thereby, the axial movement of the input shaft or the output shaft with respect to the housing is reliably restricted, and the generation of abnormal noise can be prevented.
In the present invention, the hydraulic control valve includes a valve rotor (25) provided on the input shaft or the output shaft, and surrounds the valve rotor, and is movable in one axial direction and the circumferential direction with respect to the output shaft or the input shaft. And a regulated valve sleeve (26). In this case, the axial movement of the valve sleeve relative to the housing can be restricted by restricting the axial movement of the output shaft or the input shaft relative to the housing. Thereby, the stable operation | movement of a hydraulic control valve is securable.

  In the above description, the alphanumeric characters in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of a rack and pinion type hydraulic power steering device according to an embodiment of the present invention. Referring to FIG. 1, a rack and pinion hydraulic power steering device 1 (hereinafter also simply referred to as a steering device 1) includes an input shaft 2, an output shaft 4 as a pinion shaft on which a pinion 3 is formed, and a pinion 3. And a rack shaft 6 that meshes within the housing 5, a hydraulic cylinder 7 provided in a part of the housing 5, and a hydraulic control valve 8 that controls the supply of hydraulic oil to the hydraulic cylinder 7.

  A steering member such as a steering wheel (not shown) is connected to the input shaft 2. A steering torque is input to the input shaft 2 from the steering member. Further, the input shaft 2 is coaxially connected to the output shaft 4 via a torsion bar 9. The torsion bar 9 is connected to the input shaft 2 via a pin 10 and is connected to the output shaft 4 via a serration 11. Thereby, the input shaft 2 and the output shaft 4 rotate relatively with elastic torsion of the torsion bar 9 according to the steering torque.

  The rack shaft 6 extends in the width direction of the vehicle (direction perpendicular to the paper surface of FIG. 1). Wheels (not shown) are respectively attached to both ends of the rack shaft 6. The steering torque input from the steering member is transmitted to the rack shaft via the input shaft 2 and the output shaft 4. As a result, the rack shaft 6 moves in the axial direction (direction perpendicular to the paper surface of FIG. 1), and the wheel angle changes. The rack shaft 6 is biased toward the pinion 3 by a support yoke 12 as a support member that supports the rack shaft 6. Thereby, the backlash between the pinion 3 and the rack shaft 6 is removed.

  The housing 5 includes a cylindrical pinion housing 13 and a cylindrical valve housing 14. The mutually opposing ends of the pinion housing 13 and the valve housing 14 are fitted together. A part of the output shaft 4 is inserted into the pinion housing 13, and the pinion 3 is surrounded by the pinion housing 13. The pinion housing 13 is formed with an annular flange 17 projecting from one end of the peripheral wall 15 outward in the radial direction X1 of the pinion housing 13. A part of the input shaft 2 is inserted into the valve housing 14. The valve housing 14 is formed with an annular flange 18 projecting from one end of the peripheral wall 16 outward in the radial direction X1 of the valve housing 14.

  The inner peripheral surface 15a of the peripheral wall 15 of the pinion housing 13 and the outer peripheral surface 16a of the peripheral wall 16 of the valve housing 14 are fitted to each other. The annular flange 17 of the pinion housing 13 and the annular housing 18 of the valve housing 14 are abutted against each other, and the annular flanges 17 and 18 are fastened to each other by a plurality of bolts 19 as fastening members. Thereby, the pinion housing 13 and the valve housing 14 are connected and fixed to each other.

An annular groove 20 is formed in the outer peripheral surface 16 a of the peripheral wall 16 of the valve housing 14. An elastic member 21 as a sealing member is accommodated and held in the annular groove 20. The elastic member 21 seals the fitting portion between the pinion housing 13 and the valve housing 14.
The hydraulic cylinder 7 includes a cylinder tube 22 through which the rack shaft 6 is inserted, a piston 23 provided so as to be movable integrally with the rack shaft 6, and a pair of oil chambers 24 separated by the piston 23 in the cylinder tube 22. Including. The cylinder tube 22 is connected to the pinion housing 13 and is arranged so as to intersect with the pinion housing 13.

  The hydraulic control valve 8 is provided around the input shaft 2 and is surrounded by a valve housing 14. The hydraulic control valve 8 includes a valve rotor 25 and a valve sleeve 26. The valve rotor 25 is provided, for example, integrally on the outer periphery of a part of the input shaft 2. The valve sleeve 26 concentrically surrounds the valve rotor 25. Further, the valve sleeve 26 is connected to the output shaft 4 by a pin 27 so as to be integrally rotatable. As the torsion bar 9 is twisted according to the steering torque, the input shaft 2 and the output shaft 4 are rotated relative to each other, whereby the valve rotor 25 and the valve sleeve 26 are rotated relative to each other.

  A part of the pin 27 is press-fitted and fixed in a fixing hole formed in the outer periphery 4 a of the output shaft 4, and the remaining part of the pin 27 protrudes from the outer periphery 4 a of the output shaft 4. The protruding portion of the pin 27 is inserted into a concave groove formed on the end surface of the valve sleeve 26. The pair of inner wall surfaces of the groove is, for example, inclined, and the groove width of the groove is gradually narrowed toward the bottom of the groove. The pin 27 is received by a pair of inner wall surfaces of the concave groove. Accordingly, the pin 27 restricts the valve sleeve 26 from moving downward in the axial direction Y1 of the output shaft 4.

The output shaft 4 may be biased upward in the axial direction Y1 by an elastic member.
A predetermined gap is provided between the valve rotor 25 and the valve sleeve 26, and this gap corresponds to the inter-valve oil passage 28. The inter-valve oil passage 28 is individually connected to the pair of oil chambers 24 of the hydraulic cylinder 7, the pump 33, and the tank 34 through ports 29, 30, 31, and 32 provided in the valve housing 14. . The inter-valve oil passage 28 is provided with a throttle whose opening degree changes in accordance with the relative rotation amounts of the valve rotor 25 and the valve sleeve 26. By this restriction, the hydraulic oil sent from the pump 33 is supplied to one oil chamber 24 of the hydraulic cylinder 7 according to the steering direction, and is returned to the tank 34 from the other oil chamber 24 via the hydraulic control valve 8. To do. Thereby, a steering assist force acting on the rack shaft 6 is generated.

  Further, the input shaft 2 and the output shaft 4 are rotatably supported by corresponding rolling bearings 35, 36, and 37 in the housing 5. Specifically, the input shaft 2 is supported by a rolling bearing 35 that is held by the valve housing 14. The rolling bearing 35 is composed of, for example, a ball bearing. The output shaft 4 is supported by a rolling bearing (predetermined rolling bearing) 36 and a rolling bearing 37. The rolling bearing 36 is composed of, for example, a ball bearing. The rolling bearing 36 supports the output shaft 4 between the pinion 3 and the hydraulic control valve 8 while being held in the peripheral wall 16 at one end of the valve housing 14. The rolling bearing 37 is composed of, for example, a needle roller bearing, and supports the distal end portion 4 b of the output shaft 4 while being held by the pinion housing 13.

  In the valve housing 14, oil seals 38 and 39 are disposed on both sides of the hydraulic control valve 8 sandwiched in the axial direction Y1 (vertical direction in FIG. 1). Specifically, the gap between the input shaft 2 and the valve housing 14 is sealed by an oil seal 38 interposed between the input shaft 2 and the valve housing 14. Further, the output shaft 4 and the valve housing 14 are sealed by an oil seal 39 interposed between the output shaft 4 and the valve housing 14. The oil seal 39 is disposed between the annular step portion 40 formed on the output shaft 4 and the rolling bearing 36.

  Assembling of the steering device 1 having the above-described configuration is performed as follows. First, the hydraulic pressure control valve 8, the output shaft 4, the oil seals 38 and 39, the rolling bearing 35, and the rolling bearing 36 are assembled into the valve housing 14 to form a subassembly. Next, this subassembly is inserted into the pinion housing 13 (drop-in process). After the drop-in process, the annular flanges 17 and 18 of the pinion housing 13 and the valve housing 14 are fastened to each other by a plurality of bolts 19, and the assembly of the steering device 1 is completed. In this manner, the steering device 1 is easily assembled.

Next, the fixing of the rolling bearing 36 to the valve housing 14 will be described in detail.
FIG. 2 is an enlarged sectional view showing a rolling bearing supporting the upper portion of the output shaft in FIG. 1 and its periphery. With reference to FIG. 2, a rolling bearing 36 as a predetermined rolling bearing is fixed to the valve housing 14 and the output shaft 4. Specifically, the rolling bearing 36 includes an inner ring 41 fitted to the output shaft 4 so as to be integrally rotatable, an outer ring 42 fixed to the valve housing 14, and a plurality of rollers interposed between the inner ring 41 and the outer ring 42. Rolling elements 43. The inner ring 41 is sandwiched between an inner ring receiving portion 44 formed by a step formed on the outer periphery 4a of the output shaft 4 and an annular retaining ring 45 fitted to the outer periphery 4a of the output shaft 4, and as a result, the output shaft 4, the movement of the inner ring 41 in the axial direction Y1 is restricted. The outer ring 42 has a first end surface 42a, a second end surface 42b, and an outer peripheral surface 42c. A male screw 46 is formed on the outer peripheral surface 42c. Further, on the inner peripheral surface 16 b of the peripheral wall 16 of the valve housing 14, a female screw 47 that is screwed with the male screw 46 and an outer ring receiving portion 48 configured by an annular step are formed. The outer ring 42 is fixed to the valve housing 14 by screwing the male thread 46 of the outer ring 42 into the female thread 47 of the valve housing 14. Further, the movement of the outer ring 42 in the axial direction Y <b> 1 with respect to the valve housing 14 is restricted by abutting the first end surface 42 a of the outer ring 42 against the outer ring receiving portion 48.

  As described above, according to this embodiment, the axial relative movement between the output shaft 4 and the rolling bearing 36 is restricted. The outer ring 42 of the rolling bearing 36 can be fixed to the valve housing 14 by screwing the male thread 46 of the outer ring 42 of the rolling bearing 36 with the female thread 47 of the valve housing 14. Thereby, it is possible to restrict the output shaft 4 from moving in the axial direction Y <b> 1 with respect to the housing 5. Therefore, it is possible to prevent the output shaft 4 from rattling in the housing 5 and generating abnormal noise.

Further, by restricting the movement of the output shaft 4 in the axial direction Y1, it is possible to restrict the downward movement of the valve sleeve 26 connected to the output shaft 4 that is one of the axial directions Y1. Thereby, the stable operation | movement of the hydraulic control valve 8 is securable.
Furthermore, it is only necessary to form the male screw 46 on the outer peripheral surface 42c of the rolling bearing 36 and the female screw 47 on the inner peripheral surface 16b of the valve housing 14, and there is no need to add other parts, thereby preventing an increase in cost. be able to.

FIG. 3 is a schematic cross-sectional view of a rack and pinion type hydraulic power steering apparatus according to another embodiment of the present invention. 3, the same components as those shown in FIGS. 1 and 2 described above are denoted by the same reference numerals as those in FIGS. 1 and 2, and description thereof is omitted.
Referring to FIGS. 1 and 3, the present embodiment is mainly different from the embodiment of FIG. 1 in that an integrated housing 50 in which a pinion housing and a valve housing are integrally formed is provided. There is. A male screw 460 is formed on the outer peripheral surface 351a of the outer ring 351 of the rolling bearing (predetermined rolling bearing) 350 that supports the input shaft 2, and the male screw 460 and the female screw 470 formed on the inner periphery 50b of the housing 50 are screwed. Match. Further, a needle roller bearing is used as the rolling bearing 360 that supports the upper portion of the output shaft 4, and the rolling bearing 360 and the rolling bearing 350 are mounted in the housing 50 from the upper portion of the housing 50. .

  According to the present embodiment, the axial relative movement between the input shaft 2 and the rolling bearing 350 that supports the input shaft 2 is restricted. The inner ring 352 of the rolling bearing 350 is fitted to the input shaft 2 so as to be integrally rotatable. The inner ring receiving portion 440 configured by a step formed on the outer periphery 2a of the input shaft 2 and the outer periphery 2a of the input shaft 2 are provided. It is clamped by an annular retaining ring 450 fitted together. The outer ring 351 of the rolling bearing 350 is fixed to the housing 50 by screwing a male screw 460 formed on the outer ring 351 with a female screw 470 formed on the inner periphery 50 b of the housing 50.

  As a result, the axial movement of the input shaft 2 relative to the housing 50 is restricted. On the other hand, the output shaft 4 is restricted from moving in at least one of the axial directions Y1 with respect to the input shaft 2. As a result, the movement of the output shaft 4 in the axial direction Y1 with respect to the housing 50 can be restricted. Thereby, the same effect as the embodiment in FIG. 1 can be obtained. Further, by using the integrated housing 50 in which the pinion housing and the valve housing are integrally formed, the manufacturing cost can be reduced.

  The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims. For example, the predetermined rolling bearing that is screw-coupled to the housing 5 may be a rolling bearing that supports the input shaft 2 or a rolling bearing that supports the output shaft 4. When the predetermined rolling bearing is a rolling bearing that supports the output shaft 4, the predetermined rolling bearing may be the rolling bearing 36 that supports the upper portion of the output shaft 4 as in the embodiment of FIG. 1. Further, it may be a rolling bearing 37 that supports the distal end portion 4b of the output shaft 4.

In short, it is only necessary that one or two or more predetermined rolling bearings screwed to the housing 5 are provided and at least one of the input shaft 2 and the output shaft 4 is supported by the predetermined rolling bearings.
A valve sleeve may be provided on the input shaft 2 and a valve rotor may be provided on the output shaft 4.

1 is a schematic cross-sectional view of a rack and pinion type hydraulic power steering device according to an embodiment of the present invention. It is an expanded sectional view which shows the rolling bearing which supports the upper part of an output shaft in FIG. 1, and its periphery. It is typical sectional drawing of the rack and pinion type hydraulic power steering device concerning another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Rack and pinion type hydraulic power steering device, 2 ... Input shaft, 3 ... Pinion, 4 ... Output shaft, 4a ... Outer periphery, 5, 50 ... Housing, 6 ... Rack shaft, 8 ... hydraulic control valve, 9 ... torsion bar, 16b, 50b ... inner peripheral surface, 25 ... valve rotor, 26 ... valve sleeve, 35, 37, 360 ... Rolling bearings, 36, 350... Rolling bearings (predetermined rolling bearings), 42, 351... Outer ring, 42c, 351a... Outer peripheral surface, 46, 460 ... Male thread, 47, 470. , Y1 ... Axial direction

Claims (2)

An input shaft and an output shaft connected to each other on the same axis through a torsion bar so as to be relatively rotatable;
A pinion formed on the outer periphery of the output shaft and meshing with the rack shaft;
A hydraulic control valve for generating hydraulic pressure according to the relative rotation of the input shaft and the output shaft;
A cylindrical housing surrounding the pinion and the hydraulic control valve;
A rolling bearing that supports the input shaft;
A rolling bearing for supporting the output shaft;
At least one of the rolling bearing that supports the input shaft and the rolling bearing that supports the output shaft includes a predetermined rolling bearing,
Axial relative movement between the predetermined rolling bearing and the corresponding shaft is restricted,
A rack and pinion type hydraulic power steering apparatus, wherein a male screw is formed on an outer peripheral surface of an outer ring of the predetermined rolling bearing, and the male screw is screwed into a female screw formed on an inner peripheral surface of the housing.   2. The hydraulic control valve according to claim 1, wherein the hydraulic control valve includes a valve rotor provided on the input shaft or the output shaft, and a valve that surrounds the valve rotor and is restricted from moving in one axial direction and in the circumferential direction relative to the output shaft or the input shaft. A rack and pinion type hydraulic power steering device comprising a sleeve.

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