JPH0110308Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a cylinder device used in a steering device for a vehicle such as an automobile.

In the above-mentioned steering device, a pinion of a pinion shaft connected to a handle shaft via a servo valve is engaged with a rack of a steering rod connected to a wheel side, and a piston is fitted and fixed to the steering rod. Generally used is a piston that is slidably fitted into a cylinder via a sealing member. As shown in FIG. 1, the conventional cylinder device used in this steering device has a piston 1 manufactured by machining a metal ring, such as cutting, fixed to a steering rod 2 by caulking. A seal member 3 attached to the outer periphery was slidably fitted into the cylinder 4.
However, since the piston 1 was manufactured by machining a metal ring, there were problems in that there were many manufacturing steps, it was difficult to improve productivity, and the piston was heavy. Furthermore, in this type of cylinder device, the steering rod tends to be deformed in the radial direction due to the pressing force transmitted from the wheel side, but since the piston is a substantially rigid body,
It is not possible to absorb the radial displacement of the steering rod, and as a result, the sealing member attached to the piston is compressed more than necessary, increasing the sliding resistance between the sealing member and the cylinder, and causing the piston to There was a problem in that the cylinder came into contact with the inner peripheral surface of the cylinder and was damaged.

This invention improves the piston by constructing it with a press-formed product such as a metal plate, and by forming a radial gap between the seal member holding part of the piston and the steering rod, it is different from the conventional piston described above. A steering device that solves the problem, has good productivity, is lightweight, can prevent an increase in sliding resistance between the seal member and the cylinder, and can also prevent contact between the piston and the cylinder. The purpose is to provide a cylinder device for

An embodiment of this invention will be described below with reference to FIGS. 2 to 4.

In FIG. 2, 11 is a pinion shaft, and this pinion shaft 11 is connected to a handle shaft (both not shown) via a servo valve. A pinion 12 provided on the pinion shaft 11 is connected to a steering rod 14 within a housing 13 of the steering device.
It is engaged with a rack 15 formed on one side of the holder. A cylinder 16 is provided on the other side of the housing 13.
is fixed, the steering rod 14 is inserted through the housing 13 and the cylinder 16, and both ends of the steering rod 14 protruding from these are connected to the wheels (not shown) through ball joints 17, respectively. A piston 18, which will be described later, is fitted and fixed to the other side of the steering rod 14, and a seal member 19 attached to the piston 18 is slidably fitted into the cylinder 16.

As shown in FIG. 3, the piston 18 is made of an integrally press-molded metal plate such as a steel plate,
A sealing member holding portion 18a having a U-shaped cross section and opening toward the outer circumference, and a cylindrical mounting portion 18b having approximately the same diameter as the steering rod 14 and fixed by caulking to an annular groove 14a provided in the rod 14. They are connected via a flexible connecting portion 18c and are formed offset in the axial direction of the steering rod 14. In addition, the seal member holding portion 18 of the piston 18
A gap G is formed in the radial direction between a and the steering rod 14. The seal member 19 is fitted into the seal member holding portion 18a via an elastic ring 20, and this seal member 19 protrudes from the outer periphery of the seal member holding portion 18a and comes into contact with the inner peripheral surface of the cylinder 16. There is. By caulking and fixing the cylindrical mounting portion 18b to the annular groove 14a of the steering rod 14, the piston 18 is fixed in the axial and circumferential directions of the steering rod 14, and the piston 18 and the steering rod 14 are fixed together. The liquid in the cylinder 16 is sealed between the cylinder 16 and the cylinder 16.

To manufacture the piston 18, as shown in FIG. 4, a circular metal plate is first formed into a stepped tube shape with a bottom in a press forming process a, and then formed into a cylindrical shape in a holding groove forming process b. A V-groove is formed in an annular shape on the outer periphery of the large diameter part of the molded product. Thereafter, in a holding part finish forming step c, the V groove is finished formed into the predetermined shape of the U-shaped seal member holding part 18a, and the step part of the molded product is brought into close contact with one side wall of the holding part 18a. Further thereafter, in a bottom punching step d, the bottom of the molded product is punched out to form a cylindrical attachment portion 18b having a predetermined shape, thereby obtaining a completed piston 18. This piston 18 is fitted onto the steering rod 14 with a caulking fixing process e, and the cylindrical mounting portion 18b located on the outer periphery side of the annular groove 14a is pressed from the outer periphery direction to plastically deform the cylinder. The shaped mounting portion 18b is caulked and fixed to the annular groove 14a. In the above embodiment, the piston is press-formed from a metal plate, but the piston is not limited to this, and the piston may be formed from a metal tube by drawing, roller forming, or the like.

As explained above, the cylinder device for a steering device of this invention has a piston that is opened on the outer circumferential side.
A plastic processed product in which a sealing member holding part with a letter-shaped cross section and a cylindrical mounting part, which has approximately the same diameter as the steering rod and is caulked and fixed to the steering rod, are shifted in the axial direction of the steering rod and formed integrally. Compared to conventional pistons manufactured by cutting or other machining on metal rings, the pistons created using this invention require fewer manufacturing steps, improving productivity, and the pistons are integrated into one piece. Since it is made of a molded product, it has the advantage of being lighter than conventional pistons. Furthermore, in the cylinder device of this invention, the piston is made of a plastic processed product, and a radial gap is formed between the seal member holding portion and the steering rod. When a pressing force is applied from the side, the radial deformation of the steering rod can be absorbed by the deformation of the seal member holding part of the piston, and the gap between the seal member attached to the piston and the cylinder is This has the effect of preventing an increase in the sliding resistance of the piston and damage caused by contact between the piston and the cylinder.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a piston portion of a conventional cylinder device for a steering device, FIG. 2 is a side sectional view of a cylinder device for a steering device according to an embodiment of this invention, and FIG. FIG. 4 is a side sectional view showing the piston portion of the cylinder device shown in FIG. 11...Pinion shaft, 12...Pinion, 14
... Steering rod, 15 ... Rack, 16
... Cylinder, 18 ... Piston, 18a ... Seal member holding part, 18b ... Cylindrical mounting part, 19 ...
...Seal member.

Claims (1)

[Scope of utility model registration request] The pinion of the pinion shaft connected to the handle shaft via the servo valve is engaged with the rack of the steering rod connected to the wheel side, the piston is fixed to the steering rod, and the piston is connected to the cylinder via the sealing member. In a vehicle steering device in which the piston is slidably fitted, the piston is attached to the steering rod with a sealing member holding portion having a U-shaped cross section that opens toward the outer periphery, and having a sealing member holding portion having approximately the same diameter as the steering rod. A cylindrical mounting part to be fixed by caulking is made of a plastically worked product that is integrally formed with an offset in the axial direction of the steering rod, and a radial gap is formed between the holding part and the steering rod. A cylinder device for a steering device characterized by: