JPH031345Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rack and pinion type power steering device for automobiles in which a sealing member is not used in the sliding portion of a spool valve.

[Conventional technology] Rack and pinion power steering uses hydraulic power to assist the rotation of the steering wheel and transmits it to the wheel steering arm via a gear mechanism consisting of a pinion and rack, thereby steering the wheels. Various devices have been proposed in the past, but in all cases, a spool valve that slides inside a valve case is sealed with a sealing member on the sliding surface of the valve case.

For example, FIG. 5 shows a vertical cross-sectional view of a rack and pinion type power steering device 1 disclosed in Japanese Patent Application Laid-Open No. 57-70773. The inserted spool valve 3 is sealed by an O-ring 4, which is an example of a sealing member, embedded in the outer peripheral surface of the spool valve 3 and the sliding surface 2a of the valve case 2, respectively.

[Problem that the invention attempts to solve]

For this reason, when the spool valve 3 slides, sliding resistance is generated by the O-ring 4, and this sliding resistance causes the driver to feel an unexpected weight when turning the steering wheel, resulting in poor feeling. Ta.

The purpose of the present invention is to minimize the sliding resistance when the spool valve slides, and to improve the feeling when turning the steering handle.

[Means for solving problems]

The rack and pinion type power steering device of the present invention has a pinion shaft supported by a valve case, rotates integrally with a steering handle, and is provided with a pinion, and the pinion shaft meshes with the pinion and moves reciprocally through the wheel steering arm. a rack for steering the wheels; a spool valve that is slidably inserted into the valve case and selectively supplies pressurized oil from the pump to the power cylinder; and a spool valve whose central part is inserted into the pinion shaft and is inserted into the valve case. The spool valve pivots about a part of the spool valve as a fulcrum, and the distal end faces from a communication portion formed in the valve case so as to communicate the spool valve portion and the pinion shaft portion, and engages with the spool valve. and a drive lever that communicates with the pinion shaft, wherein the pinion shaft is sealed with a sealing member between the communication portion of the valve case and the drive lever or on both sides of the drive lever. This is what I did.

[Effect]

According to the above configuration, there is no need to install a seal member on the sliding portion of the spool valve, and the sliding resistance when the spool valve slides becomes extremely small. Further, the spool valve portion and the rack and pinion portion are separated by a sealing member, so that oil in the spool valve portion does not leak into the rack and pinion portion.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows a rack and pinion type power steering device 5 according to a first embodiment of the present invention, and its outline will be explained with reference to FIG. 4 as well.

The pinion shaft 6 is rotatably supported by the valve case 8 by a pair of bearings 10 and 11 mounted on the valve case 8, and is adapted to rotate integrally with the steering handle. Also, the pinion shaft 6
A pinion 12 is integrally formed at the tip. The rack 13 meshes with the pinion 12 and reciprocates as the pinion 12 rotates, thereby steering wheels (not shown) via wheel steering arms.

The spool valve 15 is slidably inserted into the sliding surface 8a of the valve case 8, and is adapted to selectively supply pressurized oil from the pump to a power cylinder (not shown). Furthermore, annular grooves 16, 18, and 19 are formed in the spool valve 15 to form a pressure oil passage between the spool valve 15 and the sliding surface 8a of the valve case 8.

The drive lever 20 consists of a ring part 21 which is a central part that fits into the pinion shaft 6, a support part 22 which is protruded at a symmetrical position passing through the center of the ring part 21, and a drive part 23 which is a tip part. The portion 22 is inserted into the support hole 8b of the valve case 8, and the drive portion 2
3 faces from a communication part 8c formed in the valve case 8 so as to communicate the spool valve 15 part and the pinion shaft 6 part, and the spool valve 1
It is inserted into a groove 15a formed in 5.

The oil seal 25, which is an example of a sealing member, is housed in the communication portion 8c, and is made up of a single lip 28 using a spring 26 and a metal ring 30, and its outer peripheral surface is covered with rubber.

Next, the operation of the first embodiment of the present invention will be explained. Communication portion 8c of valve case 8 and drive lever 2
An oil seal 25 is connected between the lower part of the drive unit 23 and the
Since it is sealed by spool valve 1
The oil in the 5 parts (dots) does not leak into the pinion shaft 6 part, and the spool valve 15
Since the portion is not sealed, the sliding resistance of the spool valve 15 is extremely small.

FIG. 2 shows another shape of the oil seal 25, which is U-shaped, consists of a single lip without using a spring, and has an outer peripheral surface covered with rubber. FIG. 3 shows another shape of the oil seal 25, which is formed into a ring shape and consists of a single lip 32 and a metal ring 33 that do not use a spring, and whose outer peripheral surface is covered with rubber. There is. When pressed by hydraulic pressure from above, the protrusion 25a is pressed against the bottom surface of the communication part 8c, and the communication part 8c and the drive lever 20
and the lower part of the drive section 23 are sealed.

FIG. 4 shows a second embodiment of the present invention.
The pinion shaft 6 is sealed with a pair of oil seals 25 on both sides of the drive lever 20.
The oil seal 25 consists of a single lip 36 using a spring 35, a metal ring 38, and a dust lip 39 that does not use a spring, and its outer peripheral surface is covered with rubber.

Next, the operation of the second embodiment of the present invention will be explained. Since the pinion shaft 6 is sealed by a pair of oil seals 25 on both sides of the drive lever 20, the spool valve 15 portion and the drive lever 20
The oil (spotted parts) on both sides of the spool valve 1 does not leak out to the outside, and as in the first embodiment, the spool valve 1
Since the portion 5 is not sealed, the sliding resistance of the spool valve 15 is extremely small. Further, rotational resistance is generated by the oil seal 25 when the pinion shaft rotates six times, but this rotational resistance is considerably smaller than the sliding resistance of a conventional spool valve and can be ignored.

[Effect of idea]

As described above, according to the present invention, there is no need to install a seal member on the sliding portion of the spool valve, so the sliding resistance when the spool valve slides becomes extremely small. Therefore, the steering handle can be operated easily and the feeling is extremely good. Further, since the spool valve portion and the rack and pinion portion are separated by a sealing member, oil in the spool valve portion does not leak into the rack and pinion portion.

[Brief explanation of drawings]

1 to 3 relate to the first embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of a rack and pinion type power steering device, and FIG. 2 is a first embodiment showing a state in which an oil seal of a different shape is used. FIG. 3 is a partial vertical sectional view of the one shown in FIG. 1, showing a state in which an oil seal of a different shape is used, and FIG. 4 is a partial longitudinal sectional view of the one shown in FIG. Longitudinal cross-sectional view of rack and pinion power steering device,
FIG. 5 is a longitudinal sectional view of a conventional rack and pinion power steering device. 5...Rack pinion power steering device, 6...Pinion shaft, 8...Valve case, 8
c...Communication part, 12...Pinion, 13...Rack, 15...Spool valve, 20...Drive lever, 21...Ring part which is the center part, 23...Driving part which is the tip part, 25...Seal An oil seal is an example of a component.

Claims (1)

[Scope of utility model registration request] a pinion shaft that is supported by the valve case and rotates integrally with the steering handle and is provided with a pinion; a rack that meshes with the pinion and moves back and forth to steer the wheels via the wheel steering arm; and the valve case. a spool valve that is slidably inserted into the interior and selectively supplies pressure oil from the pump to the power cylinder; a drive lever that faces from a communication portion formed in the valve case so as to communicate between the spool valve portion and the pinion shaft portion, engages with the spool valve, and links the spool valve and the pinion shaft; The rack pinion type is characterized in that the pinion shaft is sealed with a sealing member between the communication portion of the valve case and the drive lever or on both sides of the drive lever. Power steering device.