JPH022696Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a rack-and-pinion type power steering device in which the cylinder has a pipe structure.

<Prior art> In a rack-and-pinion type power steering device in which the cylinder has a pipe structure, a gear housing made of aluminum has a small diameter part into which the pipe fits around the outer periphery of one end, and an end face of the pipe is attached to the terminal end of this small diameter part. Abutting step portions are formed, the pipe is fitted into and abuts the small diameter portion and the step portion, and the gear housing and the pipe are connected by a driving pin.

This type of power steering device is excellent in weight reduction due to the combination of an aluminum gear housing and a thin-walled pipe, but the joint portion between the gear housing and the pipe, that is, the step portion Since it is the weakest part, stress concentration acts here.
Therefore, there is a problem in that strict control of shrinkage cavities and the like during casting of the gear housing is required.

<Purpose> The present invention was developed in view of the above-mentioned conventional problems, and its purpose is to improve the bending rigidity at the joint between the gear housing and the pipe, and to achieve this purpose. for,
A pinion shaft that meshes with a rack shaft is supported in a gear housing made of aluminum, and one end of a pipe in which a piston provided on the rack shaft is slidably fitted is connected to a stepped portion at one end of the gear housing. In the rack-and-pinion type power steering device, reinforcing pipes are provided on the inner periphery of the gear housing and extend on both sides in the axial direction around a joint between the gear housing and the pipe.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. The gear housing 10 made of aluminum includes
A rack shaft 11 is slidably passed through the rack shaft 11, and both ends of the rack shaft 11 are connected to steering wheels via unillustrated ball joints or the like. Rack teeth 11a are formed on the outer periphery of one end of the rack shaft 11, and the rack teeth 11a mesh with a pinion shaft 14 rotatably supported by the gear housing 10. The pinion shaft 14 is connected to a steering handle via a servo valve device (not shown) or the like.

A piston 15 is provided on the rack shaft 11, and this piston 15 is slidably fitted into a pipe 16 made of steel that constitutes a cylinder. One end of the pipe 16 is connected to the gear housing 1
0, and a cylinder end (not shown) is fixed to the other end. Thus, the piston 15 divides the inside of the pipe 16 into a cylinder left chamber 16a and a cylinder 16b. Note that one end of the pipe 16 is press-fitted to a position where the end of the pipe 16 joins to the stepped portion 10b of the gear housing 10, and is fixed with a pin 17.

On the inner periphery of the gear housing 10, there is a connecting part (step part 10) between the gear housing 10 and the pipe 16.
b) A reinforcing pipe 20 extending from both sides in the axial direction is press-fitted concentrically with the rack shaft 11. This reinforcing pipe 20 is the gear housing 1
The reinforcing pipe 20 increases the bending rigidity at the joint between the gear housing 10 and the pipe 16. Note that the reinforcing pipe 20 is attached to the gear housing 1.
In addition to being attached to the inner periphery of 0 by press fitting, it can also be integrally molded by casting.

<Effects> As described above, the present invention has a structure in which reinforcing pipes 20 are provided on the inner periphery of the gear housing and extend on both sides in the axial direction around the joint between the gear housing 10 and the pipe 16. Gear housing 10 and pipe 1 are the weakest parts against bending stress
It is possible to improve the bending rigidity at the joint with 6, and there is no need for strict management of shrinkage cavities and the like as in the past.

[Brief explanation of the drawing]

The drawing is a sectional view of a rack-and-pinion type power steering device showing an embodiment of the present invention. 10...Gear housing, 11...Rack shaft,
14...Pinion shaft, 15...Piston, 16...
...Pipe, 20...Reinforcement pipe.

Claims (1)

[Scope of utility model registration request] A pinion shaft that meshes with a rack shaft is supported in a gear housing made of aluminum, and one end of a pipe in which a piston provided on the rack shaft is slidably fitted is connected to a stepped portion at one end of the gear housing. The rack-and-pinion power steering device is characterized in that a reinforcing pipe is provided on the inner periphery of the gear housing and extends on both sides of the gear housing in the axial direction around a joint between the gear housing and the pipe. And pinion type power steering device.