JP2000038150A - Hydraulic control valve for power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with a pin and a ball for assembling by providing a pair of corrugation sections integrally rotatably coupled with the inner faces of corresponding holes and a pair of guide sections arranged on the pressing-in direction side of the corrugation sections on the peripheral faces of both end sections of a torsion bar. SOLUTION: First and second corrugation sections 18, 19 made of serrations, for example, are formed on the peripheral faces of the first and second end sections 15, 16 of a torsion bar 10 respectively. For assembling a valve, the torsion bar 10 is inserted into the inside of an input shaft 8, and first and second guide sections 20, 21 are inserted into the corresponding holes 22, 23 of the input shaft 8 and an output shaft 9, thereby the alignment of the input shaft 8 and the output shaft 9, i.e., the alignment of a valve rotor 13 and a valve body 14, can be made. The positioning of the rotating direction of the valve rotor 13 and the valve body 14 is made in this state, then the torsion bar 10 is pressed into the corresponding holes 22, 23 of the input shaft 8 and the output shaft 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control valve of a power steering device for adjusting a steering assist force by a relative rotation between an input shaft and an output shaft connected via a torsion bar.

[0002]

2. Description of the Related Art In a rotary valve as a control valve for adjusting a steering assist force in a power steering apparatus, an input shaft and a torsion bar positioned in a rotational direction mutually penetrate in a radial direction. After drilling the through hole to be made, insert a pin into the formed through hole,
In some cases, these pins are mechanically connected to each other and fixed. In this case, there is a possibility that chips generated during drilling of the through hole become foreign matters and are mixed into the hydraulic oil.

On the other hand, there is a case where a ball is press-fitted into a concave portion on an end face of a torsion bar fitted to an input shaft, and the end of the torsion bar whose diameter is enlarged is frictionally coupled to the input shaft and fixed. In this case, since the regulation of the relative rotation between the input shaft and the output shaft depends only on the frictional force, the regulation of the relative rotation is insufficient.

[0004] In any case, additional parts such as pins and balls are required, which complicates the structure and increases the manufacturing cost.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an inexpensive and non-existent foreign substance.
Moreover, it is an object of the present invention to provide a hydraulic control valve of a power steering device that can surely prevent the end of the torsion bar from rotating.

[0006]

Means for Solving the Problems As means for solving the problems to achieve the above object, the aspect of the invention described in claim 1 is as follows.
In a power steering device in which both ends of a torsion bar are press-fitted into holes of an input member and an output member, respectively, the both ends of the torsion bar are integrally rotatably connected to corresponding input members and output members. The peripheral surfaces at both ends include a pair of undulating portions that are respectively rotatably fitted to the inner surfaces of the corresponding holes, and a pair of guide portions that are respectively arranged on the press-fit direction side of each undulating portion. The guide portion is inserted into the inner surface of the corresponding hole prior to the pair of undulations at the time of press-fitting both ends of the torsion bar, and guides the insertion of the pair of undulations into the corresponding hole. Is what you do.

In this aspect, when both ends of the torsion bar are press-fitted into the corresponding holes of the input member and the output member, a pair of undulations are aligned with the pair of guides previously fitted into the corresponding holes. The insertion of the part into the corresponding hole is guided.

[0008] Unlike the prior art, additional parts such as pins and balls are not required, and the end of the torsion bar can be fixed with a simple structure. Further, there is no danger of foreign matter being mixed into the hydraulic oil unlike the case where a pin is used. Furthermore, since the pair of undulations bite into the inner surface of the corresponding hole, the relative rotation of the both ends of the torsion bar with respect to the input member and the output member can be reliably restricted.

The undulation is not limited to serrations.
Any irregularities can be used as long as the rotation of the end of the torsion bar can be prevented.

According to a second aspect of the present invention, in the first aspect, the lengths of the pair of undulating portions in the press-fitting direction are equal to each other. In this aspect, it is possible to press-fit a pair of undulating portions into the corresponding holes simultaneously with a minimum press-fit stroke.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view showing the overall configuration of a power steering device including a hydraulic control valve according to an embodiment of the present invention.

Referring to FIG. 1, a hydraulic control valve 1 is provided between a power cylinder 2 and a hydraulic pump 3 and an oil tank 4 for controlling a hydraulic pressure supplied to a power cylinder 2 for generating a steering assist force. Interposed. The power cylinder 2 is formed by forming a cylinder chamber 6 by liquid-tightly sealing a part of a cylindrical rack housing (not shown) surrounding the outside of a rack shaft 5 connected to wheels. A piston 7 fixed at an intermediate portion of the rack shaft 5 is slidably fitted into the cylinder chamber 6, and oil chambers 6a,
The hydraulic pressure applied to the rack shaft 5 by the pressure difference between the rack shafts 6b directly assists the steering operation performed along the axial direction of the rack shaft 5.

In the hydraulic control valve 1, a cylindrical input shaft 8 connected to a steering wheel (steering wheel) and an output shaft 9 connected to a steering mechanism are connected via a torsion bar 10 inserted inside the input shaft 8. Coaxially connected. Double shaft 8, 9
Are rotatably supported inside a common housing 11. The housing 11 has an upper housing 11a and a lower housing 11b.

The upper end of the input shaft 8 projects from the housing 11 and is connected to a steering wheel (not shown). A pinion 12 is formed on the outer periphery of the lower half of the output shaft 9, and the pinion 12 is engaged with the rack shaft 5 inserted into the lower portion of the lower housing 11 b in a manner intersecting with the output shaft 9. ing.

A cylindrical valve body 13 held inside the housing 11 is connected to an end of the output shaft 9 connected to the torsion bar 10 by a pin 24. , Valve rotor 14
Are fitted to be relatively rotatable. This valve rotor 14 is formed integrally on the outer periphery of the input shaft 8. Between the valve body 13 and the valve rotor 14, both
A pair of throttles (not shown) whose throttle areas change in different directions according to the relative angular displacements of the throttles 3 and 14 are provided, and the valve body 13 and the valve rotor 14 forming the throttles constitute a valve mechanism V. Have been.

When the steering operation is performed, the input shaft 8 rotates around the axis, and the rotation is performed by the torsion bar 10 and the output shaft 9.
The power is transmitted to the rack shaft 5 through the pinion 12 and the rack shaft 5 slides in the axial direction to perform steering.
At this time, the torsion bar 10 connecting the input shaft 8 and the output shaft 9 is twisted according to the steering torque applied to the steering wheel. The valve body 1 described above according to this twist
3 and the valve rotor 14 cause relative angular displacement, and pressure oil from the hydraulic pump 3 is supplied to a required oil chamber 6 a or 6 b of the power cylinder 2.

The torsion bar 10 has a main body 17 having a predetermined outer diameter and a predetermined length between opposing first and second ends 15 and 16 in order to obtain desired torsional characteristics. Have. First and second ends 15, 16
Has a larger diameter than the main body 17.

On the peripheral surfaces of the first and second end portions 15 and 16 of the torsion bar 10, first and second undulating portions 18 and 19 made of, for example, serrations are formed, respectively. The second undulations 18 and 19 are press-fitted into the corresponding holes 22 and 23 of the input shaft 8 and the output shaft 9, respectively. The first and second end portions 15 and 16 of the torsion bar 10 are adjacent to the first and second undulating portions 18 and 19 on the press-fit direction side (downward in FIG. 1), and the first and second end portions 15 and 16 are adjacent to each other. Two guide portions 20, 21 are formed respectively. These guide portions 20 and 21 are used to assemble both ends 15, 1 of the torsion bar 10 when assembling the valve.
6 for guiding the undulating portions 18 and 19 into the corresponding holes 22 and 23 when press-fitting them.

Next, a process of assembling the valve will be described. Before assembling the torsion bar 10, first, the input shaft 8 and the output shaft 9, which are free from each other, are positioned in the rotational direction. Thus, the valve rotor 14 integrated with the input shaft 8 and the valve body 13 previously pinned to the output shaft 9 are aligned in the rotational direction.

Next, as shown in FIG. 2, the torsion bar 10 is inserted inside the input shaft 8, and first, the first and second guide portions 20, 21 are inserted into the corresponding holes of the input shaft 8 and the output shaft 9. Fit into 22 and 23. Thereby, the center of the input shaft 8 and the output shaft 9 is aligned, that is, the valve rotor 13
And the valve body 14 can be aligned.

With the valve rotor 13 and the valve body 14 aligned as described above, the positions of the two members 13 and 14 in the rotational direction are adjusted.

Next, the torsion bar 13 is pressed into the corresponding holes 22 and 23 of the input shaft 8 and the output shaft 9. Since the press-fitting is performed in a state where the press-fitting is performed in advance, as described above, and while being guided by the guide portions 20 and 21,
In addition to easy assembling work, assembling with high assembling accuracy can be performed.

By setting the lengths a and b of the first and second undulating portions 18 and 19 in the press-fitting direction to be equal to each other, the press-fitting stroke at the time of press-fitting both can be reduced. As a result, it is possible to achieve a small hydraulic control valve 1 by reducing the space in the vertical direction.

According to the present embodiment, there is no need to use pins or balls unlike the conventional method, so that the structure is simple and inexpensive, and the assembling is easy and the assembling accuracy is high.

In addition, since the press-fitting method is used, there is no possibility that foreign matters such as cutting chips enter the inside.

Further, since the undulating portions 18 and 19 to be press-fitted are made to bite into the inner surfaces of the corresponding holes 22 and 23, the both ends 15 and 16 of the torsion bar 10 can be surely prevented from rotating.

It should be noted that the present invention is not limited to the above-described embodiment, and the undulations need not be serrations, but may have irregularities that can prevent rotation. The unevenness may be a ridge or a ridge extending in the axial direction. In addition, various changes can be made within the scope of the present invention.

[0029]

According to the first aspect of the present invention, since no pins or balls are used for assembling the torsion bar, the structure is simple and inexpensive. Also, there is no need to drill the pin insertion hole, and there is no possibility that foreign matter such as cutting chips may be mixed into the hydraulic oil. Further, since the undulating portion cuts into the inner surface of the hole, the rotation of both ends of the torsion bar is reliably prevented.

According to the second aspect of the present invention, the overall size can be reduced by reducing the press-in stroke of the torsion bar.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a schematic configuration of a power steering device including a hydraulic control valve according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a press-fitting step for assembling a torsion bar, with hatching omitted.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 hydraulic control valve 8 input shaft (input member) 9 output shaft (output member) 10 torsion bar 11 housing 13 valve rotor 14 valve body 15 first end 16 second end 18 first undulation 19 second Undulating part 20 First guide part 21 Second guide part 22, 23 hole

Claims (2)

[Claims] 1. A power steering device in which both ends of a torsion bar are press-fitted into holes of an input member and an output member, respectively, thereby connecting both ends of the torsion bar to corresponding input members and output members so as to be integrally rotatable. In the hydraulic control valve, the peripheral surfaces of both end portions of the torsion bar are a pair of undulating portions fitted to the inner surfaces of the corresponding holes so as to be integrally rotatable, respectively, and a pair of The pair of guide portions are inserted into the inner surface of the corresponding hole earlier than the pair of undulation portions at the time of press-fitting both ends of the torsion bar, and are inserted into the corresponding holes of the pair of undulation portions. A hydraulic control valve for a power steering device, which guides the insertion of a power steering. 2. The hydraulic control valve according to claim 1, wherein the lengths of the pair of undulations in the press-fitting direction are equal.