JPH0218780Y2 - - Google Patents

Description

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

<Prior art> Conventionally, in this type of cylinder device, an oil seal is installed between the cylinder end screwed into the stepped hole opening of the cylinder tube and the rod guide, and the inner and outer circumferences of the oil seal are in close contact with the cylinder tube and the steering rod, respectively. The structure is such that the pressure fluid is prevented from leaking from the cylinder tube.

However, such oil seals do not have a sealing part formed on the end face of the cylinder end, and when the internal pressure inside the boot changes due to temperature changes, for example, the oil seal may leak between the cylinder end and the end face of the oil seal as well as through the threaded part of the cylinder end. This causes a problem in that air flows in and out, and as a result, outside air containing moisture is introduced into the boot, causing rust.

<Purpose of the invention> This invention was devised to solve the conventional problems, and its purpose is to prevent outside air from entering the boots and prevent rust from forming. .

Another object of the present invention is to prevent the seal portion that prevents the intrusion of outside air from peeling off or from increasing sliding resistance due to deformation of the seal portion.

<Structure of the invention> In order to achieve the above object, the present invention has a cylinder end side end face of the oil seal, which protrudes from the inner ring end face towards the cylinder end side, inside the inner ring and outside the back-up spring. An annular seal portion is integrally formed, and a recessed portion recessed toward the rod guide side from the inner ring end surface is formed at the base of the seal portion.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 shows a rack and pinion type steering device equipped with the device of the present invention, where 10th indicates the 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 attached to the screw 2 in the opening thereof.
5 is screwed and fixed. The oil seal 23 is held between the rod guide 22 and the cylinder end 24 .

One end of the boot 46 is fixed to the outer periphery of the end of the cylinder tube 16, and the other end is fixed to the tie rod 13.
The sealing of the boot 46 prevents muddy water from splashing onto the steering rod 11 and ball joint 12 inside the boot 46.

As shown in FIGS. 2 and 3, the oil seal 23 has a seal body 26 made of an elastic material.
, a metal inner ring 27 embedded in the outer circumference of the seal body 26, and a mounting groove 2 on the inner circumference of the seal body 26.
8 and a back-up spring 29 fitted into the holder. A seal lip 30 is formed on the inner periphery of the seal body 26, and is tightly attached to the outer periphery of the steering rod 11 by a coil spring 31 disposed behind the seal lip 30. Also, Backup Spring 29
acts to suppress excessive radial displacement of the steering rod 11.
This prevents a decrease in the adhesion force of the seal lip 30 to the seal lip 30 and the generation of a gap.

Here, an annular seal portion 32 is formed on the end surface of the all seal 23, and this seal portion 32 closely contacts the end surface of the cylinder end 24 to prevent outside air from entering. However, this seal portion 32 has various problems depending on the location where it is formed.
As shown in the figure, a seal portion 3 is provided on the outer circumferential side of the inner ring 27.
2, the oil seal 23 has a notch 36 for gripping a tool on its outer periphery, so a constriction is formed, which makes the seal part 32 easy to peel off, and as shown in FIG. 32 is formed on the inner peripheral side of the inner ring 27, this seal portion 32
This deformation causes the back-up spring 29 to deform in the radial direction, increasing sliding resistance.

Therefore, in consideration of the above problems, the present invention forms the seal portion 32 integrally with the seal main body 26 on the inner circumferential side of the inner ring 27 and on the outer circumferential side of the back-up spring 29. The rod guide 2 is attached to the base of the portion 32 from the end surface of the inner ring 27.
Recessed portions 33 and 34 are formed to be recessed toward the 4th side.

Since the seal portion 32 having such a structure has no constriction, the integrity with the seal body 26 is enhanced and peeling can be prevented, and the deformation of the seal portion 32 due to the installation of the oil seal 23 is prevented by the concave portions 33 and 34. Since it is absorbed, radial displacement of the back-up spring 29 can be prevented, and an increase in sliding resistance can be prevented.

<Effects of the invention> As detailed above, the device of the present invention has a sealing portion formed on the end face of the cylinder end of the oil seal, so it has the advantage of being able to prevent air inflow and outflow and the occurrence of rust caused by this. .

In addition, the device of the present invention has an annular seal portion integrally formed on the cylinder end side end face of the oil seal, on the inner circumferential side of the inner ring and on the outer circumferential side of the backup spring, and protruding from the inner ring end face toward the cylinder end side. Since the base of this seal part has a concave part recessed toward the rod guide side from the inner ring end surface, the seal part that prevents outside air from entering may peel off, or deformation of this seal part may cause sliding resistance. It has the advantage of not increasing.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a rack and pinion type steering device equipped with the device of the present invention, and FIG.
FIG. 3 is an enlarged sectional view of the oil seal in the figure, FIG. 3 is a view taken in the direction of the arrow in FIG. 2, and FIGS. 4 and 5 are enlarged sectional views showing comparative examples of the oil seal. 10...Housing, 14...Pinion shaft, 1
6...Cylinder tube, 20...Shoulder, 21...
...Stepped hole, 22... Rod guide, 23... Oil seal, 24... Cylinder end, 26... Boot, 32... Seal portion, 33, 34... Recessed portion.

Claims (1)

[Scope of utility model registration request] A rod guide that guides the steering rod and an oil seal whose outer circumference is reinforced with an inner ring and whose lip is backed up with a back-up spring are fitted into the stepped hole formed at the end of the cylinder tube. and a cylinder device for a steering device in which an oil seal is pressed and supported by a cylinder end screwed into the stepped hole opening on an inner shoulder of the stepped hole and a rod guide end surface, respectively. On the inner circumferential side of the inner ring and on the outer circumferential side of the back-up spring, an annular seal portion is integrally formed that protrudes from the inner ring end surface toward the cylinder end side, and the base of this seal portion is provided with a seal portion extending from the inner ring end surface toward the rod guide side. A cylinder device for a steering device, characterized in that a recessed portion is formed.