JPH0113007Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a rack-and-pinion type steering device.

<Prior art> In order to guide and support the steering rod that passes through the cylinder tube, the rod guide is fitted into a stepped hole formed inward at the end of the cylinder tube, and then an oil seal seals the steering rod side. It is conceivable that the oil seal is fitted into a stepped hole and the cylinder end is screwed into the stepped hole opening in order to sandwich the oil seal with the rod guide, but there is no seal part on the end surface of the cylinder end of the oil seal. Therefore, when the air pressure inside the boot, which has one end fixed to the cylinder end, increases due to temperature rise, air flows out from inside the boot through the threaded part of the cylinder end, passing between the end face of the cylinder end and the oil seal, and the temperature increases. When the temperature drops, the amount of air that flows out creates a negative pressure inside the boots, which could cause the boots to dent or allow water to enter.

<Purpose of the invention> The invention was made in order to eliminate such drawbacks of the conventional technology, and its purpose is to prevent water from entering the cylinder tube, which can cause rust, without increasing the number of parts. This is to prevent air from flowing into the boot and from flowing out of the boot.

<Structure of the invention> In order to achieve the above object, the present invention forms a stepped hole having a shoulder inside the end of the cylinder tube, and fits the rod guide into the stepped hole until it abuts the shoulder. Then, fit an oil seal into the stepped hole until it touches the rod guide, screw the cylinder end into the stepped hole opening until it touches the end of the cylinder tube, and then fit the oil seal into the steering rod. It is characterized by comprising a lip part that seals the cylinder end side, a first seal part with built-up thickness that seals the cylinder tube side, and a second seal part with built-up thickness that seals the cylinder end side. .

<Examples> Examples of the present invention will be described below based on the drawings. In FIG. 1, 10 indicates a housing;
This housing 10 is supported by the frame of an automobile. The steering rod 1 is attached to the housing 10.
1 is slidably passed through the steering rod 11, and both ends of the steering rod 11 are connected to tie rods 13 via ball joints 12. Steering rod 1
A rack 11a is formed on the outer periphery of one end of the housing 10, and the rack 11a is engaged with a pinion shaft 14 rotatably supported on the housing 10. The pinion shaft 14 is connected to the handle shaft via a servo valve device (not shown). The steering rod 11 is also provided with a piston 15, which is slidably fitted into a cylinder tube 16 integrally connected to the housing 10.

A stepped hole 21 having a shoulder portion 20 is formed in the inner end of the cylinder tube 16, and a rod guide 22 is fitted and supported in the stepped hole 21 so as to come into contact with the shoulder portion 20. . An oil seal 23 is laminated in this stepped hole 21 so as to be in close contact with the end surface of the rod guide 22, and a cylinder end 24 is screwed into the opening of the oil seal 23.
5 is screwed and fixed. A stepped portion is formed on the outer periphery of the cylinder end 24, and by screwing the cylinder end 24 to a position where this stepped portion abuts the end of the cylinder tube 16, the oil seal 23 is held between the rod guide 22. . One end of the boot 26 is fixed to the outer surface of the end of the cylinder tube 16, and the other end is fixed to the tie rod 13, and the sealing of the boot 26 prevents muddy water from entering the steering wheel rod 11 and the ball joint 12 inside the boot 26. This prevents this from happening.

As shown in FIGS. 2 and 3, the oil seal 23 is formed with a lip portion 23a projecting toward the steering rod 11, and the lip portion 23a is pressed against the steering rod 11 by a spring ring 27. The oil seal 23 has a first seal portion 23b formed inside on the cylinder tube 16 side.
is formed, and the cylinder tube 16 and the oil seal 23 are sealed by the first seal portion 23b. Cylinder end 2 of oil seal 23
A thickened seal portion 23c is formed on the 4 side,
The cylinder end 24 and the oil seal 23 are sealed by this second seal portion 23c. The lip portion 23a of the oil seal 23 prevents communication between the inside of the cylinder tube 16 on the rod guide 22 side and the inside of the boot 26, and the first seal portion 23b of the oil seal 23 prevents communication between the outside and the rod guide 22 side. The second seal portion 23c of the oil seal 23 can prevent communication between the outside and the inside of the boot 26. By blocking communication between the outside and the inside of the boot 26, the inflow of water from the outside and the outflow of air inside the boot 26 can be prevented.

<Effects of the invention> As described above, in the invention, the rod guide is fitted into the stepped hole of the cylinder tube until it contacts the shoulder, and the oil seal is fitted into the stepped hole until it contacts the rod guide. Since the cylinder end is screwed into the stepped hole opening and fixed to the position where it abuts the end of the cylinder tube, the oil seal can be held with a small number of parts. In addition, since the oil seal is equipped with a first seal part with built-in thickness that seals the cylinder tube side and a second seal part with built-in thickness that seals the cylinder end side, there is no need to use an O-ring between the outside and the inside of the boot. It is possible to prevent communication between the outside and the inside of the cylinder tube on the rod guide side. By blocking communication between the outside and the inside of the boot, it is possible to prevent water from flowing into the cylinder tube, which causes rust, and there is an advantage that air from inside the boot can be prevented from flowing out.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Fig. 1 is a sectional view of a rack and pinion type steering device, and Fig. 2 is a sectional view of a rack and pinion type steering device.
FIG. 3 is an enlarged sectional view of the oil seal in the figure, and FIG. 3 is a view taken in the direction of the arrow in FIG. 10...Housing, 14...Pinion shaft, 1
6...Cylinder tube, 20...Shoulder, 21...
...Stepped hole, 22...Rod guide, 23...Oil seal, 23c...Seal portion, 24...Cylinder end, 26...Boot.

Claims (1)

[Scope of utility model registration request] A pinion shaft operated by a steering handle is rotatably supported in the housing, a steering rod that meshes with the pinion shaft is inserted into a cylinder tube integrally connected to the gear housing, and tie rods are attached to both ends of the steering rod. A stepped hole having a shoulder is formed in the cylinder tube inwardly at its end, a rod guide is fitted into the stepped hole until it abuts against the shoulder, and an oil seal is fitted into the stepped hole. The cylinder end is screwed into the stepped hole opening until it contacts the end of the cylinder tube, and the cylinder end and the tie rod are fitted with a boot that covers the end of the steering rod. The oil seal includes a lip portion that seals the steering rod side, a first seal portion that is thickened to seal the cylinder tube side, and a second seal portion that is thickened to seal the cylinder end side. A rack-and-pinion type steering device.