JP2001063594A - Mount structure of rack and pinion type steering gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely fix a mount bracket on a thin cylinder tube by interposingly pressing the mount bracket between the cylinder end and an end surface of the cylinder tube by the cylinder end. SOLUTION: A cylinder tube 13 of a power cylinder is composed of a thin steel pipe. A screw part 21 is formed on the other end inner periphery of the cylinder tube 13, and the cylinder end 22 is fastend/fixed to this screw part 21. In this case, the cylinder end 13 is fastened/fixed to the cylinder tube 13 so as to sandwich a mount bracket 26 between the cylinder end and an end surface of the cylinder tube 13. One end of a rack shaft 14 is supported by a rack guide arranged on the back face side of a meshing part with a pinion shaft, and the other end of the rack shaft 14 is borne by a bearing bush 24 installed on the inner periphery of the cylinder end 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure for a rack-and-pinion type steering gear, and more particularly to a mounting structure in which a mounting bracket can be easily and reliably mounted on a cylinder tube.

[0002]

2. Description of the Related Art In general, in a rack and pinion type steering gear, a steering gear box is constituted by a gear housing and a cylinder tube having one end fixed to the gear housing. In the gear housing, a pinion shaft connected to the steering wheel side is rotatably supported, and a rack shaft that meshes with the pinion shaft is slidably supported. The attached piston is slidably fitted.

In this type of rack and pinion type steering gear, a steering gear box is elastically supported by a body frame at two points on the left and right sides of the rack axis. That is, the gear housing side and the cylinder tube side are each elastically supported by the vehicle body frame via the mount bracket.

In the conventional mounting structure, the mounting bracket provided on the gear housing side can be formed integrally with the gear housing by casting, but the cylinder tube side is formed by a thin steel tube because the cylinder tube is formed of a thin steel pipe. Usually, the mount bracket is fixed to the outer periphery of the cylinder tube by welding.

[0005]

In the conventional rack pinion steering gear mounting structure described above,
When welding the mount bracket to a thin cylinder tube, welding distortion is likely to occur in the cylinder tube,
This distortion changes the squeeze of the O-ring and the oil seal attached to the site. As a result, the reliability of the rack and pinion steering gear decreases, and in the worst case, oil leakage easily occurs.

A method of fixing the mount bracket to the outer periphery of the cylinder tube by press fitting is also conceivable.
In order to support the rotational force and the axial force acting on the steering gear box only by press-fitting, the press-fitting stiffness must be increased, which causes a problem that the deformation of the cylinder tube becomes large.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems.
One end of the cylinder tube of the power cylinder is fixed to a gear housing that slidably supports a rack shaft that meshes with a pinion shaft, and is press-fitted to the outer periphery of the other end of the cylinder tube in a mount bracket on the cylinder tube side. When the press-fitting hole of the mount bracket is press-fitted to the outer circumference of the other end of the cylinder tube, the mount bracket is screwed into the inner circumference of the other end of the cylinder tube. The cylinder tube is clamped and fixed to the end face of the cylinder tube by a cylinder end that is fastened and fixed to the cylinder tube.

According to a second aspect of the present invention, the mount bracket on the gear housing side is formed integrally with the gear housing by casting.

According to a third aspect of the present invention, each of the mount brackets on the gear housing side and the cylinder tube side includes
The elastic body is elastically supported on the vehicle body frame via a rubber bush body.

[0010] According to the first aspect of the present invention, the mount bracket does not deform the cylinder tube by using both the press-fitting action to the outer circumference of the cylinder tube and the pinching action between the cylinder end and the cylinder tube. It can be securely fixed on the cylinder tube.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a 10 steering gear box.
0 is the gear housing 11 and the gear housing 11
And a cylinder tube 13 having one end fixed to the outer periphery of the cylindrical mounting portion 12 by press-fitting. The steering gear box 10 includes a rack shaft 14
Are the gear housing 11 and the cylinder tube 13
A piston 15 is mounted on the rack shaft 14 so as to be slidably fitted to the cylinder tube 13. These cylinder tubes 13
The power cylinder 16 assists the steering torque with the piston 15.

A pinion shaft 17 meshing with the rack shaft 14 is rotatably supported by the gear housing 11. As is well known, the pinion shaft 17 is connected to a steering shaft via a torsion bar (not shown), and the steering shaft is rotated by operating a steering wheel. The gear housing 11 houses a control valve (not shown) that is operated by the relative rotation between the steering shaft and the pinion shaft 17. The operation of the control valve causes the supply and discharge of the pressure oil to and from the power cylinder 16. It is controlled.

The cylinder tube 13 of the power cylinder 16 is made of a thin steel pipe. As shown in detail in FIG.
1 is formed, and a cylinder end 22 is fastened and fixed to the screw portion 21. At this time, the cylinder end 22 is fixedly fastened to the cylinder tube 13 so that a mount bracket 26 described later is sandwiched between the cylinder end 13 and the end surface of the cylinder tube 13. One end of the rack shaft 14 has a rack guide 2 provided on the back side of a portion meshed with the pinion shaft 17.
3 and the other end of the rack shaft 14 is supported by a bearing bush 24 mounted on the inner periphery of the cylinder end 22.

The steering gear box 10 has a mounting bracket 25 at two points on the axis of the rack shaft 14,
The vehicle is supported by a vehicle frame (not shown) via an opening 26. One mount bracket 25 is integrally formed with the gear housing 11 by casting, and the other mount bracket 26 is mounted on the cylinder tube 13 as described later.

As shown in FIG. 4, the mount bracket 26 has a cylindrical portion 3 fitted into the cylinder tube 13.
1 and a mounting portion 32 extending radially outward of the cylindrical portion 31 and mounted on the vehicle body frame.
A press-fitting hole 33 for press-fitting the outer periphery of the cylinder tube 13 and an engaging hole 34 smaller in diameter than the press-fitting hole 33 are formed in the cylindrical portion 31. 35 is formed at right angles to the press-fitting hole 33. A rubber bush 37 is fitted into a mounting hole 35 formed in the mounting portion 32, and the mounting bracket 2 is inserted by a not-shown tightening bolt through which the rubber bush 37 is inserted.
5, 26 are elastically supported by the body frame.

In the cylinder tube 13,
An O-ring 39 is attached to the mounting portion of the mount bracket 26.
And an oil seal 40, an O-ring 39 liquid-tightly seals a fitting portion between the cylinder end 22 and the cylinder tube 13, and an oil seal 40 is a fitting portion between the cylinder end 22 and the rack shaft 14. Is liquid-tightly sealed.

In FIG. 4, the rubber bush body 37
Is a flanged outer sleeve 41 fitted in the mounting hole 35.
And a flanged inner sleeve 42 through which the tightening bolt is inserted.
And a flanged rubber ring 43 bonded between the outer sleeve 41 and the inner sleeve 42 by vulcanization bonding or the like. The rubber bush bodies 37 are mounted on both sides of each of the mounting holes 35 so that the flanges are respectively joined to both ends of the mounting holes 35. By inserting these rubber bush bodies 37 and fastening bolts to the vehicle body frame, The mount brackets 25 and 26 are elastically supported so as to be displaceable in the axial and radial directions of the tightening bolt.

Next, the procedure for mounting the mount bracket 26 on the cylinder tube 13 will be described. The mounting bracket 26 is press-fitted with its press-fitting hole 33 to the outer periphery of the cylinder tube 13 with a predetermined press-in allowance, and one end of the engaging hole 34 is engaged with the end face of the cylinder tube 13. Thereafter, the cylinder end 22 is fastened and fixed to the screw portion 21 formed on the inner periphery of the cylinder tube 13. By tightening and fixing the cylinder end 22, the other end of the engagement hole 34 of the mount bracket 26 is pressed by the shoulder of the cylinder tube 13, and the mount bracket 26 is pinched between the cylinder tube 13 and the cylinder end 22. You.

As described above, the mounting bracket 26 acts on the steering gear box 10 (cylinder tube 13) by using both the press-fitting action on the outer periphery of the cylinder tube 13 and the pinching action between the cylinder end 22 and the cylinder tube 13. Since the force in the rotating direction and the force in the axial direction are supported, the press fit can be reduced, and the deformation of the cylinder tube 13 due to the press fit can be reduced.

Therefore, the O-ring 3 attached to the site
9 and the oil seal 40 can be stabilized, and a highly reliable rack and pinion type steering gear can be obtained.

According to the above-described embodiment, the mount bracket 26 is mounted on the cylinder tube 13 by using both the press-fitting action on the outer circumference of the cylinder tube 13 and the pinching action between the cylinder end 22 and the cylinder tube 13. Since the mounting bracket 26 is fixed, the mounting bracket 26 can be easily and securely fixed without deforming the thin cylinder tube 13.

Accordingly, there is an advantage that the mount bracket can support the rotational force and the axial force without generating welding distortion unlike the case where the mount bracket is fixed to the cylinder tube by welding.

[0023]

As described above, according to the present invention, the mount bracket can be mounted on the thin cylinder tube by using both the press-fitting action on the cylinder tube outer circumference and the pinching action between the cylinder end and the cylinder tube. The mounting bracket can be easily and reliably fixed on a thin-walled cylinder tube, and there is an advantage that welding distortion or the like unlike the case of fixing by welding is not generated.

[Brief description of the drawings]

FIG. 1 is an external view of a rack and pinion type steering gear showing an embodiment of the present invention.

FIG. 2 is a sectional view of the rack and pinion type steering gear shown in FIG.

FIG. 3 is an enlarged view of a main part of FIG. 2;

FIG. 4 is a sectional view taken along line AA of FIG. 2;

[Explanation of symbols]

 Reference Signs List 10 steering gear box 11 gear housing 13 cylinder tube 14 rack shaft 16 power cylinder 17 pinion shaft 21 screw portion 22 cylinder end 25, 26 mount bracket 33 press-fitting hole 37 rubber bushing

Claims (3)

[Claims] 1. A rack shaft meshing with a pinion shaft is slidably supported on a gear housing, and one end of a cylinder tube of a power cylinder is fixed to the gear housing. At a point, the mounting structure for supporting the rack and pinion type steering gear to the vehicle body frame via the mounting bracket, the mounting bracket on the cylinder tube side is:
The cylinder bracket has a press-fitting hole which is press-fitted around the other end of the cylinder tube, and the mount bracket is fitted with the press-fitting hole of the mount bracket at the other end of the cylinder tube. A rack and pinion type steering gear mounting structure, wherein a cylinder end is fastened and fixed to a threaded portion formed on the inner periphery of the other end of the cylinder tube so as to pinch the cylinder tube with an end face of the cylinder tube. . 2. The rack pinion type steering gear mounting structure according to claim 1, wherein the mount bracket of the mounting means on the gear housing side is formed integrally with the gear housing by casting. 3. The rack pinion type steering gear mounting structure according to claim 2, wherein each of the mount brackets on the gear housing side and the cylinder tube side is elastically supported on the vehicle body frame via a rubber bushing body.