JP2011051377A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device equipped with a dust cover, in which rigidity against rolling-up of the duct cover is improved, deformation at assembly of the dust cover is decreased, and occurrence of abnormal noise at use is decreased. <P>SOLUTION: In the steering device equipped with the dust cover, the dust cover includes: a small cylinder part in sealing contact with a pinion shaft; a large cylinder part opposing to an opening of a pinion shaft storage part; and another cylinder part between the small cylinder part and the large cylinder part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a steering apparatus, and more particularly to a steering apparatus having a dust cover for preventing dust from opening at an end of a cylindrical pinion shaft housing portion of a gear housing.

  As a steering device having this type of dust cover, one disclosed in Patent Document 1 is known.

  As a seal for sealing a shaft having a longitudinal groove such as a spline or serration, a thin circular lip having an inner diameter smaller than the valley diameter of the longitudinal groove is integrally provided, and the thin circular lip is inserted into the shaft. Sometimes, the vertical groove can be closed by breaking into a shape following the vertical groove. As a result, a sealing effect can be obtained with a relatively small insertion load.

  In the steering device having the conventional dust cover shown in FIG. 3, the dust cover 200 hermetically contacted with the pinion shaft 7 is opened at the end of the cylindrical portion 5 a of the cylindrical pinion shaft housing portion branched from the gear housing 5. The dust is prevented from entering the cylindrical opening of the gear housing.

  More specifically, the dust cover 200 is formed continuously from the small cylindrical portion 201 that is in sealing contact with the pinion shaft 7 and the end of the small cylindrical portion 201 and extends outward in the radial direction of the pinion shaft 7. The disk portion 202 includes a large cylindrical portion 203 formed continuously from the outer peripheral portion of the disk portion 202 and having the same central axis as the pinion shaft 7. The inner peripheral surface of the large cylindrical portion 203 and the gear housing The outer peripheral surface of the end portion of the cylindrical portion 5a is opposed to each other through the grease 8 so as to be relatively rotatable.

  In this case, since the outer diameter of the large cylindrical portion 203 is relatively large with respect to the outer diameter of the small cylindrical portion 201, the area of the disk portion 202 connecting them becomes large. Therefore, the cylindrical portion 5a of the gear housing and the large cylindrical portion 203 are in strong contact with each other due to insufficient rigidity, and the large cylindrical portion 203 is turned up, and the dustproof property of the dust cover 200 is reduced. There is a possibility that abnormal noise may be generated by contacting the cylindrical portion 5a with the large cylindrical portion 203 turned up.

  Further, when the dust cover 200 is inserted into the pinion shaft 7 and assembled, the dust cover 200 is easily deformed, and thus there is a problem that it is difficult to insert. Further, when the dust cover 200 is assembled in a deformed state, the large cylindrical portion 203 and the cylindrical portion 5a are locally in contact with each other, and there is a possibility that abnormal noise is generated when the pinion shaft rotates.

No. 7-44859

  The problem to be solved by the present invention is to improve the rigidity against turning of the dust cover in a steering device having a dust cover, and to reduce the occurrence of deformation or the like when the dust cover is assembled. The present invention provides a steering device that is less likely to occur.

  In order to solve the above problems, a steering device of the present invention includes a pinion shaft housing portion branched from a cylindrical gear housing that covers a rack passed between a pair of steering wheels, and the pinion shaft housing portion. A pinion shaft which is received and meshes with the rack and whose upper end protrudes outward from the pinion shaft housing portion; a dust cover which is hermetically contacted with the pinion shaft and disposed adjacent to the opening of the pinion shaft housing portion; The dust cover includes: a small cylindrical portion that is in sealing contact with the pinion shaft; a large cylindrical portion that faces the opening of the pinion shaft accommodating portion; and the small cylindrical portion and the large cylindrical portion. Another cylindrical portion is provided between them.

  According to the present invention, since another cylindrical portion is provided between the small cylindrical portion and the large cylindrical portion, the large cylindrical portion is not turned over, and the generation of abnormal noise can be prevented. In addition, there is an effect that the dust cover is not easily deformed when inserted into the pinion shaft, and the assembling work is facilitated.

It is pinion shaft accommodating part sectional drawing of the gear housing which concerns on embodiment of this invention. It is the B section enlarged view of FIG. It is sectional drawing of the pinion shaft accommodating part of the conventional gear housing. It is the schematic which shows an example of the state which mounted the steering device of this invention in the vehicle.

  Hereinafter, a steering apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a schematic diagram showing the steering device according to the present embodiment mounted on a vehicle. FIG. 1 is an enlarged view of part A of the configuration of FIG. FIG. 2 is an enlarged view of a portion B in FIG.

  The steering apparatus for an automobile is configured as shown in FIG. 4, and transmits the rotation of the steering wheel 1 to the pinion shaft 7 of the steering gear unit 11, and a pair of left and right tie rods 6 as the pinion shaft 7 rotates. 6 is pushed and pulled to give a steering angle to the front wheels (steering wheels: not shown). The steering wheel 1 is supported and fixed to the rear end portion of the steering shaft 9, and the steering shaft 9 is rotatably supported in a state where the electric power steering device 2 is inserted. Further, the front end portion of the steering shaft 9 is connected to the rear end portion of the intermediate shaft 4 via a universal joint 12, and the front end portion of the intermediate shaft 4 is connected to the pinion shaft 7 via another universal joint 13. is doing. The illustrated example incorporates an electric power steering device 2 that reduces the force required to operate the steering wheel 1 using the electric motor 3 as an auxiliary power source.

  A steering device having a rack and pinion type steering gear unit 11 that uses a rack and pinion as a mechanism for converting a rotational motion input from the steering wheel 1 into a linear motion for giving a steering angle is a small-sized steering device. In addition, it is widely used because it can be made lightweight and has high rigidity and good steering feeling. The steering gear unit 11 is formed by meshing pinion teeth 7 a (FIG. 1) provided on a part of the pinion shaft 7 with rack teeth provided on a rack (not shown) built in the steering gear unit 11. When the pinion shaft 7 is rotated by the operation of the steering wheel 1, the rack is displaced in the axial direction within the rack housing portion of the gear housing 5 based on the engagement of the pinion teeth 7 a and the rack teeth, and 1 is coupled to both ends thereof. The pair of tie rods 6 and 6 are pushed and pulled to give a desired steering angle to the steered wheels.

  FIG. 1 shows an example of an embodiment of a dust cover of a steering device of the present invention. FIG. 1 is an enlarged view of a portion A in FIG. 4, and is an enlarged cross-sectional view of a cylindrical pinion shaft housing portion branched from a rack housing portion of the gear housing 5 of the steering gear unit 11. The pinion shaft 7 is rotatably held by a bearing 10 fixed to the inner peripheral surface of the cylindrical portion 5a of the pinion shaft housing portion of the gear housing 5, and pinion teeth 7a are formed at the lower portion as viewed in FIG. Yes.

  An internal thread 5b is formed on the inner peripheral surface of the open end of the cylindrical portion 5a of the pinion shaft accommodating portion, and the outer ring of the bearing 10 is fixed by screwing with a bearing support member 11 having an external thread 11a formed on the outer peripheral surface. Is pressed in the axial direction to hold the bearing 10 at a fixed position in the axial direction. The bearing support member 11 has a protruding portion 11b that protrudes from the pinion shaft housing portion opening when screwed and fixed to the cylindrical portion 5a of the pinion shaft housing portion. The outer peripheral surface of the oil seal 14 is press-fitted and fixed to the inner peripheral surface of the protruding portion 11b. The outer peripheral surface of the protrusion 11b has a cross-sectional shape such as a circle or a hexagon. A seal lip is provided on the inner peripheral surface of the oil seal 14 and is in sealing contact with the outer peripheral surface of the pinion shaft 7. This prevents intrusion of dust from the end opening of the pinion shaft housing portion 5a.

  A small-diameter portion 7 b that is in sealing contact with the inner peripheral surface of the first cylindrical portion 101 of the dust cover 100 is formed in the vicinity of the opening of the cylindrical portion 5 a of the gear housing 5 in the outer peripheral surface of the pinion shaft 7. By making a part of the pinion shaft 7 have a small diameter, the dust cover 100 can be easily positioned when the dust cover 100 is inserted into the pinion shaft and assembled. Further, the inner peripheral surface of the third cylindrical portion 105 of the dust cover 100 is disposed adjacent to the outer peripheral surface of the opening end portion of the cylindrical portion 5a of the gear housing 5 via a gap, and grease 8 is interposed in the gap. Yes. As shown in FIG. 1, the grease 8 is applied to the entire circumferential direction from the inner peripheral surface of the third cylindrical portion 105 to the inner peripheral surface of the second cylindrical portion 103.

  The configuration of the dust cover 100 will be specifically described. The dust cover 100 is a molded product made of resin or rubber. A first cylindrical portion 101 is hermetically contacted with the outer peripheral surface of the small-diameter portion 7b of the pinion shaft 7 on the center side in the radial direction of the dust cover 100, and extends from the end portion toward the radially outward direction of the pinion shaft. The first disk portion 102 is formed continuously. Further, a second cylindrical portion 103 is continuously formed from the outer peripheral portion of the first disc portion 102 toward the axial direction of the pinion shaft 7, and the diameter of the pinion shaft 7 is further extended from the end portion of the second cylindrical portion 103. A second disc portion 104 extending outward in the direction is continuously formed. A third cylindrical portion 105 is continuously formed from the outer peripheral portion of the second disc portion 104 toward the axial direction of the pinion shaft 7.

  The inner diameter of the second cylindrical portion 103 is formed larger than the maximum outer diameter of the protruding portion 11 b of the bearing support member 11. Moreover, the internal diameter of the 3rd cylindrical part 105 is formed larger than the largest outer diameter of the opening end part outer periphery of the cylindrical part 5a of a pinion shaft accommodating part.

  The first cylindrical portion 101 of the present embodiment corresponds to the small cylindrical portion of the claims, and the third cylindrical portion 105 of the present embodiment corresponds to the large cylindrical portion of the claims.

  FIG. 2 is an enlarged view of the periphery of the third cylindrical portion 105, and is an enlarged view of the B portion of FIG. FIG. 1 shows a diagram in which the grease 8 is interposed between the inner peripheral surface of the third cylindrical portion 105 and the outer peripheral surface of the opening of the cylindrical portion 5a of the gear housing 5, but FIG. In the figure, the grease 8 is omitted.

  Two annular protrusions 105 a and 105 b formed continuously in the circumferential direction are formed on the outer peripheral surface of the third cylindrical portion 105 so as to be separated from each other in the axial direction of the pinion shaft 7. In addition, two annular grooves 105 c and 105 d are formed on the inner peripheral surface of the third cylindrical portion 105 so as to correspond to the protrusions and are spaced apart from each other in the axial direction of the pinion shaft 7. . In the illustrated example, two protrusions 105a and 105b and two grooves 105c and 105d are formed. However, the present invention is not limited to this, and one or more protrusions may be provided.

  Next, the operation of the steering apparatus in the present embodiment will be described with reference to FIGS. 4 and 1. When the steering wheel 1 is operated, the pinion shaft 7 is rotated with the rotation of the steering shaft 9, and the rack is displaced in the axial direction based on the meshing of the pinion teeth 7a and the rack teeth (not shown), and coupled to both ends thereof. The pair of tie rods 6 and 6 are pushed and pulled to give a desired steering angle to the steered wheels.

  In this case, the dust cover 100 hermetically contacted with the pinion shaft 7 rotates integrally with the pinion shaft 7, and the outer peripheral surface of the third cylindrical portion 105 of the dust cover and the open end portion of the cylindrical portion 5 a of the gear housing. The surface rotates relative to each other via the grease 8. The small diameter portion 7b of the pinion shaft 7 and the first cylindrical portion 101 are hermetically contacted, and the inner peripheral surface of the third cylindrical portion 105 and the outer peripheral surface of the opening end portion of the cylindrical portion 5a of the gear housing are interposed via grease. Therefore, it is possible to prevent dust from entering from the opening end of the cylindrical portion 5a of the gear housing.

  Further, as the pinion shaft 7 rotates, the seal lip of the oil seal 14 slides with respect to the pinion shaft 7, and it is possible to further prevent dust from entering from the opening end of the cylindrical portion 5a of the gear housing. it can.

  The dust cover has a stepped shape in which a second cylindrical portion 103 exists between a first cylindrical portion 101 fixed to the pinion shaft 7 and a third cylindrical portion 105 facing the cylindrical portion 5a of the gear housing. It has become. Because of such a stepped configuration, the rigidity of the third cylindrical portion 105 against turning is improved. For example, a part of the circumferential direction of the third cylindrical portion 105 of the dust cover does not turn over due to strong contact with the gear housing, and accordingly, the dust cover 100 and the gear housing are locally contacted and different. It is possible to prevent the generation of sound and prevent the sealing performance of the third cylindrical portion 105 from being lowered.

  Further, by forming two protrusions 105a, 105b on the outer peripheral surface of the third cylindrical portion 105 and further forming groove portions 105c, 105d on the inner peripheral surface, the third cylindrical portion is turned upside down. The rigidity is further increased, and it is possible to prevent the generation of abnormal noise. Further, the two annular grooves 105c and 105d can hold the grease 8, and it is possible to prevent the grease from being cut and to keep the dustproof effect for a long time.

  Further, even if the length of the pinion shaft 7 protruding from the opening of the cylindrical portion 5a of the gear housing 5 is longer than usual, the dust cover 100 is inserted to the small diameter portion 7b that is a predetermined assembly position of the pinion shaft 7. By doing so, the dust cover will not be turned up and assembly workability will be improved.

  Further, by providing the second cylindrical portion 103, the space from the outer peripheral surface of the protruding portion 11b of the support member 11 to the inner peripheral surface of the second cylindrical portion 103 is reduced. The shape of the space from the space between the outer peripheral surface of the cylindrical portion 5a of the pinion shaft housing portion and the inner peripheral surface of the third cylindrical portion 105, which is an entrance for dust intrusion, to the seal lip of the oil seal 14 is also obtained. It becomes a stepped shape, further improving the dustproof performance. Furthermore, since the space from the outer peripheral surface of the protruding portion 11b of the support member 11 to the inner peripheral surface of the second cylindrical portion 103 is reduced, grease is interposed therebetween, and the dustproof performance is improved.

  Although the rack and pinion mechanism is shown as the gear unit of the present invention, the present invention is not limited thereto, and for example, a ball screw mechanism may be used. Further, in the present embodiment, the stepped shape has only one second cylindrical portion 103 between the first cylindrical portion 101 and the third cylindrical portion 105, but a plurality of cylindrical portions are further provided. It is good also as a multistage stepped shape.

  The present invention can be used for an electric power steering device or the like.

1 Steering wheel
2 Electric power steering device
3 Electric motor
4 Intermediate shaft
5 Gear housing
5a Cylindrical part
6 Tie rod
7 Pinion shaft
8 Grease
9 Steering shaft
10 Bearing
11 Bearing support member
12 Universal joint
13 Universal joint
14 Oil seal
100 dust cover
101 First cylindrical part
102 First disc
103 Second cylindrical part
104 Second disc
105 Third cylinder
105a, 105b ridge
105c, 105d Groove

Claims (3)

A pinion shaft accommodating portion branched from a cylindrical gear housing covering a rack passed between a pair of steered wheels;
A pinion shaft housed in the pinion shaft housing portion, meshing with the rack, and having an upper end protruding outward from the pinion shaft housing portion;
In the steering device having a dust cover that is hermetically contacted with the pinion shaft and disposed adjacent to the opening of the pinion shaft housing portion,
The dust cover includes a small cylindrical portion that is in sealing contact with the pinion shaft, a large cylindrical portion that faces the opening of the pinion shaft accommodating portion, and another cylinder between the small cylindrical portion and the large cylindrical portion. A steering device characterized in that a portion is provided.   The steering device according to claim 1, wherein an annular groove is formed on an inner peripheral surface of the large cylindrical portion of the dust cover.   The steering device according to claim 1, wherein an annular protrusion is formed on an outer peripheral surface of the large cylindrical portion of the dust cover.

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