JPH09249141A - Power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a pressing part and a pressure insertion part close to thereby prevent generation of deformation in a torsion bar by forming a flange part ahead of pressure insertion part at one end of the torsion bar, pressure inserting the pressure insertion part in an opening part after pressing the flange part, allowing the flange part to press a projection part, and then performing caulking. SOLUTION: An upper surface 24a of flange part 24 of torsion bar 11 is pressed by a caulking jig 10 and a serration part 11b of a torsion bar 11 is pressure inserted into an opening 12a of a pinion shaft 12. In this case, a projection 12b formed annularly in the axial direction of the opening 12a is plastically deformed by a lower surface 24b of the flange 24, and the serration part 11b is caulked and fixed to the opening 12a. Since the upper surface 24a is pressed in this way at the time of pressure insertion, the pressed part and pressure insertion part are made close, whereby no deformation is caused in the bar 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering system for steering wheels of an automobile.

[0002]

2. Description of the Related Art Generally, in a power steering apparatus, between an input shaft connected to a steering wheel and an output shaft connected to a rack shaft for steering wheels, depending on relative rotation of the input shaft and the output shaft. A servo valve is provided which is activated to control the supply and discharge of working fluid to and from the power cylinder. In order to generate relative rotation between the input shaft and the output shaft, the input shaft and the output shaft are connected by a torsion bar that can be twisted.

Usually, as shown in FIG. 5, the connection between the torsion bar 2 and the output shaft 3 is an end portion 2a connected to the input shaft.
Is pressed by the press-fitting jig 1 to press-fit the press-fitting portion 2b into the opening 3a of the output shaft 3, and thereafter, as shown in FIG. 6, the caulking jig 4 plastically deforms the protruding portion 3b of the output shaft opening 3a. By doing so, the torsion bar 2 is caulked and fixed to the output shaft 3 as shown in FIG.

[0004]

However, when the torsion bar 2 is press-fitted into the opening 3a, the torsion bar 2 itself is deformed because the end portion 2a which is the pressing portion and the press-fitting portion 2b which is the press-fitting portion are separated from each other. There was a fear that
On the other hand, the servo valve is composed of two valves respectively connected to an input shaft and an output shaft, and these two valves are concentrically and relatively rotatably arranged with a radial clearance. When the torsion bar 2 is deformed, the positional relationship between the two valves of the servo valve is deviated when there is no steering, which may result in poor steering characteristics, such as light right steering but heavy left steering during steering of the steering wheel. If the torsion bar 2 is forcibly assembled in a deformed state, an excessive force is applied to the servo valve and the clearance between the two valves is lost, resulting in resistance when the steering wheel is steered. is there.

Further, as shown in FIGS. 5 and 6, the press-fitting step and the caulking step are required separately, so that there is a problem that the work is troublesome.

[0006]

In order to solve the above-mentioned problems in the present invention, in the first aspect of the present invention, a collar portion is provided in front of the press-fitting portion of the torsion bar, and a surface of the output shaft facing the press-fitting portion is provided. An opening is formed in the opening, and a protrusion is formed annularly in the axial direction of the opening, and when the press-fitting portion is press-fitted into the opening by the collar, the protrusion abuts the collar and plastically deforms. However, the press-fitting portion is caulked and fixed to the output shaft.

A second aspect of the present invention is characterized in that a conical surface having a concave cross section is formed in an annular shape on a surface of the collar portion that abuts the protruding portion. (Operation) In claim 1, when the collar portion provided in front of the press-fitting portion is pressed by the press-fitting jig into the opening portion of the output shaft, the collar portion is formed annularly in the axial direction of the opening portion. The protrusion is plastically deformed by being brought into contact with the formed protrusion, and the press-fitting portion is caulked and fixed to the opening.

According to the second aspect of the present invention, when the conical surface comes into contact with the projecting portion at the time of press-fitting, a force radially inward acts on the projecting portion, and press-fitting and caulking work can be performed more easily.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the power steering apparatus according to the present invention applied to a rack and pinion type apparatus.
In FIG. 1, reference numeral 15 denotes a rack housing which is a main body of the power steering apparatus. A pinion shaft (output shaft) 12 is rotatably supported by bearings 17 and 18 in the rack housing 15, and the pinion shaft 12 is It is meshed with a rack shaft 16 which is slidable in a direction intersecting with this. Both ends of the rack shaft 16 are connected to steering wheels (not shown) through a required link mechanism, and pistons of a power cylinder (not shown) are operatively connected to the rack shaft 16.

A valve housing 19 is fixed to the rack housing 15, and a servo valve 20 is housed in the valve housing 19. The servo valve 20 is composed of a sleeve valve member 21 and a rotary valve member 22 which are rotatable relative to each other about the axis of the pinion shaft 12. The sleeve valve member 21 is connected to the pinion shaft 12 by a connecting pin 23, The valve member 22 is integrally formed with the input shaft 14 connected to a steering handle (not shown). The input shaft 14 and the pinion shaft 12 are connected by a torsion bar 11 so as to be relatively rotatable. A serration portion (press-fitting portion) 11 is provided at one end of the torsion bar 11.
b is formed, and the collar portion 2 is provided in front of the serration portion 11b.
4 is provided, and the serration portion 11b is fixed to the pinion shaft 12 by caulking. The other end 11a of the torsion bar is connected to the input shaft 14 by a connecting pin 13.

An opening 12a is formed on the surface of the pinion shaft 12 that faces the serration portion 11b, and an annular projection 12b is formed in the opening 12a in the axial direction. The torsion bar 11 has the opening 12
The protrusion 12b is press-fitted into a and is plastically deformed to be caulked and fixed to the pinion shaft 12. Next, the operation of the above configuration will be described.

When the steering wheel is steered, the torsion bar 11 is twisted between its both ends 11a and 11b, and the input shaft 14 and the pinion shaft 12 rotate relative to each other, and the sleeve valve member 21 and the rotary valve member 22 accordingly. Also relatively rotates, and the working fluid corresponding to this rotation is guided to the power cylinder connected to the rack shaft 16 and serves as an assisting force when steering the wheels.

Next, the operation of press-fitting and caulking the serration portion 11b of the torsion bar 11 into the opening 12a of the pinion shaft 12 will be described. As shown in FIG. 2, the upper surface 24 a of the collar portion 24 of the torsion bar 11 is caulked by the caulking jig 1.
The serration part 11b of the torsion bar 11 is pressed into the opening 12a of the pinion shaft 12 by being pressed by 0. At that time, as shown in FIG. 3, the lower surface 2 of the collar portion 24 is
The protrusion 12b formed in a ring shape in the axial direction of the opening 12a is plastically deformed by 4b, and the torsion bar 11
The serration portion 11b is fixed to the opening 12a of the pinion shaft 12 by caulking.

Since the upper surface 24a of the collar portion 24 is pressed during press-fitting as described above, the pressed part and the press-fitted part are close to each other, and the torsion bar 11 is not deformed as in the conventional case. Further, since the lower surface 24b of the collar portion 24 simultaneously performs the crimping at the time of press-fitting, the press-fitting step and the crimping step are completed in one step. In the above, the lower surface 24b of the collar portion 24 forms a flat surface perpendicular to the axial direction of the torsion bar 11, but as shown in FIG. 4, the lower surface 24b of the collar portion 24 has a cross section. By forming the concave conical surface 24c in an annular shape, during press-fitting work, a force is exerted by this surface to positively orient the protrusion 12b inward in the radial direction, so that press-fitting and caulking work can be performed more easily. You can

[0015]

As described above, according to the present invention, the collar portion is provided in front of the press-fitting portion at one end of the torsion bar, and the collar portion is pressed to press-fit the press-fitting portion into the opening and the collar portion projects. Since it is decided to perform the caulking work by pressing, the pressed part and the press-fitted part are close to each other, the deformation of the torsion bar is eliminated, and the steering characteristic is stabilized.

Further, since the press-fitting step and the crimping step can be performed simultaneously in one step, the working efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a power steering apparatus equipped with the present invention.

FIG. 2 is a press-fit of a torsion bar according to an embodiment of the present invention,
It is a figure which shows the state before crimping.

FIG. 3 is a press fit of a torsion bar according to an embodiment of the present invention,
It is a figure which shows the state after crimping.

FIG. 4 is a cross-sectional view showing a collar portion of a torsion bar according to another embodiment of the present invention.

FIG. 5 is a view showing a state before press-fitting and caulking of a conventional torsion bar.

FIG. 6 is a view showing a state after press fitting of a conventional torsion bar and before caulking.

FIG. 7 is a view showing a state after press-fitting and caulking of a conventional torsion bar.

[Explanation of symbols]

 11 Torsion Bar 11a End Part 11b Serration Part (Press-fitting Part) 12 Pinion Shaft (Output Shaft) 12a Opening 12b Projection 14 Input Shaft 16 Rack Shaft 20 Servo Valve 24 Collar

Claims (2)

[Claims] 1. An input shaft connected to a steering handle, an output shaft connected to a rack shaft for steering wheels, a torsion bar connecting the output shaft and the input shaft so as to be relatively rotatable, The output shaft includes a servo valve that is operated according to the relative rotation of the input shaft and the output shaft due to the torsion of the torsion bar to control the supply and discharge of the working fluid to and from the power cylinder, and is press-fitted to the output shaft at one end of the torsion bar. A press-fitting part is formed, the press-fitting part is press-fitted onto the output shaft, and is caulked and fixed, and the other end is connected to the input shaft.In the power steering device, a collar part is provided in front of the press-fitting part. An opening is provided on a surface of the output shaft that faces the press-fitting portion, a projecting portion is formed annularly in the axial direction of the opening, and the projecting portion is formed when the press-fitting portion is press-fitted into the opening by the collar portion. Is in contact with the collar and is plastic Shape, and power steering apparatus characterized by caulking fixing the press-fitting portion to the output shaft. 2. The power steering apparatus according to claim 1, wherein a conical surface having a concave cross section is formed in an annular shape on a surface of the collar portion that comes into contact with the protruding portion.