JPH04110674U - Power steering device - Google Patents

Abstract

(57) [Summary] [Purpose] To sufficiently suppress the eccentricity of the rack shaft and to suppress the hitting noise that occurs when the rack shaft is eccentric. [Structure] A rack bushing includes a rack shaft 1 which is housed in a rack shaft case 2 and whose one end meshes with a pinion shaft 4, and which is arranged between the meshing part and the other end of the rack shaft 1 inside the rack shaft case 2. 22 and intermediate bush 26 placed in the middle
At the same time, rack bush 22, intermediate bush
A piston 21 fixed in the middle of the rack shaft 1 is fitted into a cylinder formed by sealing between 26 and 26 with a first sealing member 24 and a second sealing member 25, respectively, to form a hydraulic cylinder for steering assistance. The intermediate bushing 26 is configured to be elastically deformable in a direction intersecting the axis of the rack shaft 1.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a rack and pinion type power steering device.

0002

[Conventional technology]

A rack-and-pinion power steering system that steers a car uses pins connected to the steering wheels. A piston is provided on the rack shaft that engages with the rack shaft, and the rack shaft and this are housed. An oil chamber is formed between the cylindrical rack shaft case and the steering force applied to the steering wheel is transferred to the oil chamber. By supplying pressure oil according to the amount of pressure required to move the rack shaft, It is designed to assist in the power of

0003 The rack shaft is pinned in a pinion case connected to one end of the rack shaft case. The meshing part is pushed by the support yoke. Pressure is applied to maintain a constant state of engagement. rack pini like this In the on-type power steering mechanism, the support yoke and the rack shaft case The rack shaft is supported by the rack bushing, which is a support member provided at the other end. It was supposed to be done. Further, the oil chamber is located in the rack shaft on the rack shaft. The sealing member provided on the bush side and the shaft sealing member provided on the support yoke side. It was designed to be sealed by two shaft sealing members.

0004 However, in the power steering device as described above, reverse input from the vehicle side is applied to the rack shaft. If this occurs, the rack shaft will be deflected. This deflection is handled by the rack shaft supporting yaw. Since it is supported by the rack and rack bush, there is no support that exists in the middle of these. The size increases near the sealing member provided on the toyoke side, so if the sealing member is A large eccentric force acts on the sealing member, and this eccentric force deteriorates the sealing member and shortens its life. There was a problem with the issue.

[0005] To solve this problem, in the past, the rack was only activated when the rack axis was bent. The support yoke side of the sealing member provided on the support yoke side to support the shaft. is equipped with an intermediate bush having a minute clearance with respect to the rack axis, and the intermediate bush A power steering device is being considered that suppresses the eccentricity of the rack shaft by .

[0006]

[Problem that the idea aims to solve]

However, in the power steering device equipped with the intermediate bush as described above, the plow If the distance is too large, eccentricity of the rack shaft cannot be sufficiently suppressed, and If the above clearance is made too small, the rack shaft will not move between the intermediate brackets even when the rack shaft is slightly eccentric. Please set an appropriate clearance to prevent the collision from colliding with the mesh. It was difficult to determine and impractical.

[0007] The present invention was developed in view of the above circumstances, and is designed to sufficiently prevent eccentricity of the rack shaft. To provide a power steering device that suppresses hitting noise when a rack shaft is eccentric. With the goal.

[0008]

[Means to solve the problem]

The power steering device according to the present invention is housed in a cylinder, and one end thereof is connected to the pinion shaft. The meshing rack shaft is connected to its meshing part, the other end of the rack shaft inside the cylinder body, and the middle part of the rack shaft. The supporting members placed in the respective parts are used to support the parts, while the sealing members are used to seal between the two supporting members. A piston fixed in the middle of the rack shaft is fitted into the cylinder formed by the In a power steering device constituted by a hydraulic cylinder for assisting the rudder, the midway portion is supported. The supporting member is configured to be elastically deformable in a direction intersecting the axis of the rack shaft. It is characterized by:

[0009]

[Effect]

When the rack shaft is bent, the middle part of the rack shaft in particular becomes eccentric. The support member that supports the middle part of the rack shaft is elastically deformed in the direction that intersects with the axial direction of the rack shaft. shape to suppress eccentricity of the rack shaft beyond a predetermined amount. The support member is arranged in the radial direction of the rack shaft. Since the rack shaft is elastically deformed in the direction, the rack shaft collides with the intermediate bushing due to the deflection of the rack shaft. Even if the impact force is absorbed by the elastic deformation of the support member, The hitting sound caused by the collision is suppressed.

0010

【Example】

EMBODIMENT OF THE INVENTION Hereinafter, this invention will be specifically explained based on drawing which shows the Example. Figure 1 is the main idea. FIG. 2 is a longitudinal sectional view showing a power steering device according to the proposal.

[0011] In the figure, 1 has a circular cross section with rack teeth 10 formed on one side in the axial direction. This is the rack axis. This rack shaft 1 has a cylindrical shape, and its longitudinal direction is the left-right direction. A rack shaft case 2 fixed to a part of the vehicle body and one end of the rack shaft case 2 Inside the coaxially connected cylindrical pinion case 3, the rack teeth 10 are The pinion case 3 is inserted coaxially with the pinion case 3 in such a way that the part is located therein. .

0012 The rack teeth 10 of the rack shaft 1 are mounted inside the pinion case 3 for operation (not shown). It is designed to mesh with pinion teeth 40 of a pinion shaft 4 that is interlocked with the steering wheel. , the rack shaft 1 is configured to move in the axial direction by steering the steering wheels. Pi On the back side of the area where the rack shaft 1 and pinion shaft 4 engage in the union case 3, A guide hole 31 is formed in a direction perpendicular to the rack axis 1. In order to ensure that the rack teeth 10 and pinion teeth 40 mesh, the rack shaft 1 is moved toward the pinion shaft side. A support yoke 5 is provided to press against the support yoke. On the other hand, the other end of the rack shaft case 2 A rack bush 22 that supports the other end of the rack shaft 1 is provided inside the section. , a rack bushing is located inside the rack shaft case 2 on the outside in the axial direction of the rack bushing 22. A rack stopper 23 is provided to prevent the rack 22 from moving outward in the axial direction.

[0013] In addition, the rack shaft case 2 has an oil chamber between the rack shaft case 2 and the rack shaft 1. The oil chamber is formed by an oil seal provided on the inner circumference of the rack bushing 22. The first sealing member 24 is provided in the middle of the rack shaft case 2 in the axial direction. The rack shaft 1 is sealed by a second sealing member 25 made of an oil seal. It is divided into oil chambers 20a and 20b via a piston 21 provided around it. These oil chambers Hydraulic oil for steering assistance is selectively supplied to 20a and 20b from a hydraulic pump (not shown). The supply of hydraulic oil causes the rack shaft 1 to move in the axial direction. movement is supported.

[0014] An intermediate bracket for supporting the rack shaft 1 is provided on the support yoke 5 side of the second sealing member 25. 26 is provided. One end of the rack shaft 1 is connected to the support yoke 5. The other end is supported by the rack bushing 22, and the other end is supported by the rack bushing 22. The intermediate portion is supported by an intermediate bush 26. Rack axis 1 is The left side (not shown) is connected via ball joints, link members, etc. (both not shown) arranged at both ends. It is designed to be connected to the right wheel. Then, as the steering wheel rotates, the axis The wheels are steered by moving in the opposite direction.

[0015] Fig. 2 is a schematic vertical cross-sectional view of the vicinity of the intermediate bush 26, and Fig. 3 is taken along line III-III in Fig. 2. FIG. As shown in FIG. 2, the second sealing member 25 is attached to the rack shaft case 2. The oil chamber 20a is arranged in a first diameter-reduced portion 2a that is one step smaller in diameter than the portion where the oil chamber 20a is formed. The intermediate bushing 26 is connected to the first reduced diameter portion 2a. and is arranged in the second reduced diameter part 2b which is reduced in diameter by one step. It has become. Due to the shape of the rack shaft case 2, the second sealing member 25 2. Movement in the axial direction is prevented at the end of the reduced diameter portion 2b. Also, the intermediate bush The tube 26 is arranged at a small distance from the second sealing member 25 in the axial direction.

[0016] As shown in FIG. 3, the intermediate bush 26 has a protrusion 26 that protrudes radially inward. 0,260,... are equally distributed in the circumferential direction, and these protruding parts 260,260,... are arranged around the rack shaft 1. The other portions are in contact with the inner circumferential surface of the rack shaft case 2. like this With the intermediate bushing 26 having such a structure, when the rack shaft 1 is bent, the protrusions 260, 260,... It is designed to elastically deform outward in the radial direction. This elastic deformation causes the protrusions 260, 260, Since the deformation is set to the maximum value of the protruding amount of the rack shaft 1, the deflection of the rack shaft 1 is It is limited to a protrusion amount of 260,... or less.

[0017] FIG. 4 is a schematic longitudinal sectional view of the vicinity of the intermediate bush 26 showing another embodiment of the present invention. be. 27 in the figure is a circle provided between the intermediate bush 26 and the rack shaft case 2. It is a cylindrical intermediate bushing case. The intermediate bushing case 27 is on the second sealing member 25 side. A protrusion 271 that protrudes radially inward is provided on the inner peripheral surface of the end of the second sealing member. The inner peripheral surface of the end on the member 25 side has approximately the same diameter as the inner diameter of the first reduced diameter part 2a, and a radially outer It has a shape in which a flange portion 272 that protrudes from the side is provided around the periphery, and a protrusion 271 is formed. The intermediate bushing 26 is fitted onto the inner circumferential portion other than that portion. Inside this The bushing case 27 has a flange portion 272 that is connected to the second reduced diameter portion 2a of the first reduced diameter portion 2a. It is disposed within the rack shaft case 2 so as to be located within the end on the side of the section 2b. in this way The protrusion 271 and flange portion 272 on the intermediate bush case 27 are formed. The end face on the side that is in contact with the end face of the second sealing member 25, and the protrusion 271 and the flange portion 272 restricts movement of the second sealing member 25 toward the support yoke 5 side. It looks like this.

[0018] In the power steering system configured as described above, the reverse input from the vehicle side is applied to the rack shaft 1. If given, rack shaft 1 is deflected and rack shaft 1 is eccentric, and the amount of eccentricity is It becomes particularly large near the intermediate bush 26, but the intermediate bush 26 has an elastically deformable structure. Because of the structure, the intermediate bushing 26 deforms elastically against the bending of the rack shaft 1. Suppress the eccentricity. The intermediate bush 26 has its protruding parts 260, 260,... constantly racked. Since it is in contact with shaft 1, if rack shaft 1 is deflected, rack shaft 1 will be Since it is designed not to collide with bush 26, the hitting noise caused by the collision is suppressed. be done. Also, even if the rack shaft 1 collides with the intermediate bush 26 for some reason, , the collision force is absorbed by the elastic deformation of the intermediate bushing 26, so the collision The resulting hitting sound is suppressed.

[0019]

[Effect of the idea]

As described in detail above, in the power steering device according to the present invention, when the rack shaft is bent, The middle part of the rack shaft becomes eccentric, but in this case, the bearing that supports the middle part of the rack shaft Since the member is elastically deformed in the direction that intersects the axis of the rack shaft, this elastic deformation causes The eccentricity of the rack shaft can be sufficiently suppressed, and the deflection of the rack shaft can Even if the rack shaft collides with the intermediate bushing, the collision force is due to the elasticity of the support member. Since it is absorbed by deformation, it is possible to suppress the hitting noise caused by the collision. etc., the present invention has excellent effects.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a power steering device according to the present invention.

FIG. 2 is a schematic vertical cross-sectional view of the vicinity of the intermediate bush.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a schematic longitudinal cross-sectional view of the vicinity of the intermediate bush showing another embodiment of the present invention.

[Explanation of symbols]

1 Rack axis 2 Rack shaft case 4 Pinion shaft 5 Support yoke 21 Piston 22 rack bushing 24 First sealing member 25 Second sealing member 26 Intermediate bush

Claims (1)

[Scope of utility model registration request] 1. A rack shaft that is housed in a cylindrical body and has one end that meshes with a pinion shaft, and a support member that is disposed at the meshing part and at the other end and middle part of the rack shaft inside the cylindrical body. A piston fixed to the middle of the rack shaft is fitted into a cylinder formed by sealing the space between both supporting members with a sealing member, thereby forming a hydraulic cylinder for steering assistance. A power steering device characterized in that a support member that supports the midway portion is configured to be elastically deformable in a direction intersecting the axis of the rack shaft.