JPH0213762Y2 - - 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 power steering device, etc.

<Prior art> Generally, in such a cylinder device, the cylinder device integrated with the servo valve device is installed horizontally on a support frame disposed at the bottom of the engine room, and then the piping is connected to the pump unit. In this state, air remains inside the cylinder device, so it is necessary to vent the air by some method.

In order to make this air removal easier, the supply and discharge port of the cylinder device can be formed at the top of the cylinder body, and the pressure oil can be supplied and discharged from above the cylinder device. In this case, since the pipe attachment portion faces upward, there is a problem that the piping for communicating between the cylinder body and the servo valve device may interfere with the engine or the like located above the cylinder body.

For this reason, conventionally, JP-A-55-135211
As shown in the figure, an annular groove is formed on the outer periphery of the inner end of the plug attached to the end of the cylinder tube, and this annular groove is communicated with the cylinder chamber at the upper position in the installed state. A method has been considered in which air is vented without being affected by the mounting position of the supply/discharge port by forming a passageway and communicating the supply/discharge port with the annular groove.

However, with this method, the annular groove and passage must be formed by machining in the metal plug attached to both ends of the cylinder body, which not only makes machining the plug complicated, but also requires the annular groove. It is necessary to increase the length of the stopper in the axial direction in order to form the stopper, and there is also the problem that the weight increases.

<Purpose of the invention> Therefore, the present invention is designed to form a recess for communication between the upper part of the cylinder chamber and the port without performing any special processing on the plug attached to the end of the cylinder tube. It is an object of the present invention to provide a cylinder device having an air venting function that can be easily processed and has no risk of increasing weight.

<Structure of the invention> An oil seal having a lip portion that makes sliding contact with the outer peripheral surface of the shaft is disposed at the inner end of a plug fixed to the end of the cylinder tube, and the oil seal has the above-mentioned seal on the inner end side of the oil seal. A large diameter portion that joins with the inner circumferential surface of the cylinder tube is integrally formed, a recess is formed in the circumferential direction on the outer periphery of the large diameter portion, a passage is provided that communicates this recess with the cylinder chamber only at the upper portion, and the cylinder A port for supplying and discharging pressure oil to and from the chamber is provided at a position other than the upper side in the attached state, and this port is communicated with the recess.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 shows a rack-and-pinion type power steering device, which is mounted on a mounting frame (not shown) so that the axis of the cylinder device 11 is horizontal. ing.
A tie rod 16 is connected to both ends of a steering shaft 12 that extends through the cylinder device 11 in the axial direction through a universal joint 15.

A rack 13 is formed on the outer periphery of the right end of the steering shaft 12.
is engaged with a pinion shaft 14 rotatably supported on the housing 10. This pinion shaft 14 is connected to a handle shaft via an unillustrated servo valve device.

The cylinder device 11 includes a cylinder tube 1
7, a housing 10 to which one end of the cylinder tube 17 is fixed and which forms one plug, and a cylinder end 18 which is screwed to the other end of the cylinder tube 17 and forms the other plug,
A steering shaft 12 is fixedly attached to the cylinder device 11, and a piston 19 is slidably fitted therein. Note that 20 is a rack guide.

Further, a steering shaft 12 is provided at the inner end of the housing 10 and the cylinder end 18.
Oil seals 22 and 23 having lip portions that come into sliding contact with the outer circumferential surfaces of the oil seals 22 and 23 are attached. Of these oil seals 22 and 23, the oil seal 22 is a normal oil seal, but the oil seal 23 is integrally formed with a recess and a passage for air venting.

That is, the inner end of the oil seal 23 has a second
As shown in the figure, a large diameter portion 23b extending toward the cylinder chamber 11b is formed integrally with the lip portion 23a, and the outer circumferential surface of the large diameter portion 23b is in contact with the inner circumferential surface of the cylinder tube 17. There is. and,
As shown in FIG. 3, a recessed portion 23c of a predetermined width is formed on the outer periphery of the large diameter portion 23b over a range of approximately 90 degrees from the upper portion in the installed state. A passage 23d parallel to the axis that communicates between the cylinder chamber 11b and the recess 23c is formed only in that portion. The recess 23c and the passage 23d are also integrally molded together with the lip 23a when the oil seal 23 is produced. Note that the oil seal 23 is press-fitted into the housing 10 and is prevented from rotating relative to the housing 10.

Furthermore, attachment bosses 25 and 26 are attached to the outer periphery of the cylinder tube 17, in which ports 25a and 26a for attaching pipes are formed. Of these mounting bosses 25 and 26, the cylinder end 18
The side attachment boss 25 is attached to the upper part of the cylinder tube 17 so that there is no fear of interference from the engine, etc., and the port 25a is communicated with the cylinder chamber 11a through the communication hole 27. On the other hand, the mounting boss 26 on the housing 10 side is mounted horizontally at a position other than the upper part, for example, at an axial position corresponding to the recess 23c of the oil seal 23, since there is a risk of interference with the engine, etc. The cylinder tube 17 has a communication hole 2 for communicating the port 26b with the recess 23c of the oil seal 23.
8 is drilled.

In the cylinder device configured as described above, since the mounting portion of the pipe on the housing 10 side faces in the horizontal direction, the piping does not interfere with the engine, etc. located above the cylinder device 11, and the recessed part Due to the effects of 23c and passage 23d, air remaining in the cylinder device can also be easily removed.

That is, to bleed air, after attaching the power steering device to the automobile, the pump is operated to supply pressurized oil, and in this state the steering wheel is rotated left and right several times to the end of its stroke. As a result, the piston within the cylinder device also moves repeatedly from the neutral position to the left stroke end and the right stroke end, thereby discharging the air within the cylinder device 11. That is, due to the reciprocating motion of the piston 19, the air that has accumulated in the upper part of the cylinder chamber 11a is discharged together with the fluid in the cylinder chamber 11a through the communication passage 27 to the port 25a, and is collected in the upper part of the cylinder chamber 11b. Regarding the air, together with the fluid in the cylinder chamber 11b,
It is discharged to the port 26b through the passage 23d, the recess 23c and the communication passage 28.

In the above embodiment, the recess 23c was formed in a range of 90 degrees in the circumferential direction, but the large diameter portion 2
It may be an annular groove surrounding the entire outer periphery of 3b.

<Effects of the invention> As described above, in the present invention, an oil seal is attached to the inner end of the plug attached to the end of the cylinder tube, and a recess for air vent is formed in this oil seal. This concave portion can be integrally formed with the lip portion of the oil seal, which has the advantage of providing a cylinder device having an air venting function that is easy to machine and does not increase in weight.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a cross-sectional view showing the overall configuration of a rack-and-pinion power steering device, and FIG. 2 is an enlarged view of the oil seal 23 portion in FIG. 1. FIG. 3 is a sectional view taken along the - line in FIG. 2. 10...Housing, 11...Cylinder device,
12...Steering shaft, 14...Pinion shaft, 16...Piston, 20...Rack guide, 22, 23...Oil seal, 23b...Large diameter portion, 23c...Recess, 23d...Passage, 25,
26...Mounting boss, 25a, 26a...Port,
27, 28...Communication hole.

Claims (1)

[Scope of utility model registration request] The cylinder device is installed horizontally in a vehicle, etc., and includes an oil seal having a lip portion slidingly in contact with the outer circumferential surface of the shaft, at the inner end of a plug fixed to the end of a cylinder tube through which the shaft passes. At the same time, a large diameter part is integrally formed on the inner end side of the oil seal to join with the inner circumferential surface of the cylinder tube, and a recess is formed in the circumferential direction on the outer periphery of this large diameter part. The cylinder chamber is provided with a passage communicating only at the upper part, a port for supplying and discharging pressure oil to and from the cylinder chamber is provided at a position other than the upper part in the installed state, and this port is communicated with the recessed part. cylinder device.