JP2015000635A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering device which is prevented from co-rotating and improved in sealability.SOLUTION: A steering device 1 comprises: a steering shaft 61 that steers a steering shaft 11 via a tie rod 12 connected to the steering shaft 11 of a vehicle; a cylindrical housing 62 that houses the steering shaft 61 to be movable in a direction of the shaft; a ball joint 7 that connects an end portion of the steering shaft 61 to the tie rod 12; an expandable cylindrical bellows 63, one end portion 63b of which is fixed to the housing 62, that covers the ball joint 7; and a co-rotation preventing member 9 that is provided between the other end portion 63c of the bellows 63 and the tie rod 12 and suppresses rotation of the other end portion 63c of the bellows 63 in association with rotation of the tie rod 12.

Description

  The present invention relates to a steering device.

  Conventionally, a steering device including a rack and pinion mechanism includes a pinion shaft that rotates by rotating a steering wheel, a rack shaft that moves in an axial direction by rotation of the pinion shaft, a tie rod that connects the rack shaft and the knuckle arm, It is comprised including the bellows which covers the edge part of a rack axis | shaft (for example, refer patent document 1 and 2).

  In the steering device described in Patent Document 1, the tie rod has a female screw portion and a male screw portion, and the length of the tie rod can be adjusted by relatively rotating the female screw portion and the male screw portion. . The male screw part is connected to the end of the rack shaft via an inner ball joint, and the female screw part is connected to the steered wheel via an outer ball joint and a knuckle arm. One end portion of the bellows is attached to the male screw portion by a clip, and the other end portion of the bellows is attached to a rack housing that accommodates the rack shaft.

JP 2001-39320 A JP 2013-10373 A

  By the way, in the assembly line of the vehicle using the steering device described in Patent Document 1, for example, the length of the tie rod is adjusted by relatively rotating the female screw portion and the male screw portion of the tie rod, and the angle of the steered wheels is adjusted. Toe-in adjustment is performed. When performing this toe-in adjustment, since the steered wheel is connected to the female screw portion via the outer ball joint and the knuckle arm, the female screw portion cannot be rotated and the male screw portion is rotated. . On the other hand, since the one end part of the bellows is attached to the male screw part, when the male screw part is rotated, one end part of the bellows rotates together with the male screw part, and the bellows may be twisted.

  In the steering device described in Patent Document 2, in order to perform toe-in adjustment without twisting the bellows, the first rod of the inner ball joint and the second rod of the outer ball joint are threaded in directions opposite to each other. Both the rod and the second rod are screwed together and connected to a female screw formed on a cylindrical connecting member. In the toe-in adjustment, the axial distance between the first rod and the second rod is adjusted by rotating the connecting member. Thereby, toe-in adjustment can be performed without twisting the bellows.

  However, according to the configuration described in Patent Document 2, it is necessary to thread each of the first rod and the second rod, and a cylindrical connecting member having a female screw formed on the inner peripheral surface is newly provided. Since this is necessary, the number of processing steps and the number of parts increase, which may cause an increase in cost. In this respect, the steering device described in Patent Document 2 still has room for improvement.

  Therefore, an object of the present invention is to provide a steering device capable of suppressing twisting of a bellows while suppressing an increase in cost.

  In order to achieve the above object, the present invention provides a steered shaft that steers the steered wheel via a tie rod connected to a steered wheel of a vehicle, and a cylindrical shape that accommodates the steered shaft so as to be axially movable. A ball joint connecting the end portion of the steered shaft and the tie rod, a cylindrical bellows made of an extendable resin having one end portion fixed to the housing and covering the ball joint, and the bellows There is provided a steering device including a co-rotation preventing member that is interposed between the other end portion and the tie rod and suppresses the rotation of the other end portion of the bellows accompanying the rotation of the tie rod.

  According to the present invention, it is possible to suppress twisting of the bellows while suppressing an increase in cost.

It is a schematic structure figure showing a steering device provided with a bellows concerning an embodiment of the invention. It is sectional drawing which shows the edge part of a bellows, and its inside. It is a fragmentary sectional view which shows the edge part of the bellows which concerns on the modification of embodiment of this invention.

  FIG. 1 is a schematic configuration diagram showing a steering apparatus 1 including a bellows 63 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the end of the bellows 63 and the inside thereof. In FIG. 2, one bellows 63 is shown, but the other bellows 63 is configured in the same manner.

(Overall structure of steering device)
The steering device 1 includes a steering wheel 2 that is rotated by a driver, a steering shaft 3 having the steering wheel 2 fixed at one end, a steering assist device 4 that assists steering by generating assist torque, and a steering assist device 4. The intermediate shaft 5 connected to the output shaft 40 and the steering mechanism 6 having the pinion shaft 60 connected to the intermediate shaft 5 are provided.

  The steering shaft 3 is rotatably supported inside the steering column 30 and rotates integrally with the steering wheel 2. The steering assist device 4 includes an electric motor and a speed reducer, and applies assist torque according to the steering torque of the steering wheel 2 to the output shaft 40.

  The steering mechanism 6 includes a pinion shaft 60 that rotates by operating the steering wheel 2, a rack shaft (steering shaft) 61 having rack teeth 611 that mesh with pinion teeth 601 formed on the outer peripheral surface of the pinion shaft 60, and a rack It has a cylindrical housing 62 that accommodates the shaft 61 so as to be movable in the axial direction. The rack shaft 61 is supported by the housing 62 via a rack bush (not shown). The rack shaft 61 is formed with a female screw hole 610 (shown in FIG. 2) that opens to the end surface in the rack axis direction.

  The rack shaft 61 steers the steered wheel 11 via a rod-shaped tie rod 12 connected to the steered wheel 11 of the vehicle. The tie rod 12 can be adjusted in axial length by relatively rotating a female screw portion and a male screw portion (not shown). The rack shaft 61 and the tie rod 12 are connected by a ball joint 7. The turning angle of the steered wheel 11 changes according to the amount of displacement of the rack shaft 61 in the axial direction.

  As shown in FIG. 2, the ball joint 7 includes a joint housing 70 fixed to the end of the rack shaft 61 and a ball stud 120 formed at the end of the tie rod 12 on the inner side in the vehicle width direction. . The joint housing 70 rotatably holds the ball head 121 of the ball stud 120.

  The joint housing 70 integrally includes a socket-shaped main body 71 that accommodates the ball head 121 of the ball stud 120 and a screw portion 72 that is screwed into the female screw hole 610 of the rack shaft 61. A space 710 for accommodating the ball head 121 is formed in the main body portion 71, and a shaft portion of the ball stud 120 is led out from the space 710.

  The housing 62 includes a cylindrical main body portion 62a that accommodates the rack shaft 61 so as to be movable in the axial direction, and an annular rack stopper 620 provided inside the end portion 62b of the main body portion 62a. In the present embodiment, the rack stopper 620 is press-fitted into a recess 62c formed at the end 62b of the main body 62a.

(Configuration of the end of the bellows)
The bellows 63 is made of a flexible resin such as rubber. The bellows 63 includes an expandable and contractible cylindrical bellows portion 63a that covers the ball joint 7 that is a connecting portion of the rack shaft 61 and the tie rod 12, and a cylindrical one end portion 63b that is fitted to the end portion 62b of the housing 62. A cylindrical other end 63c that is fitted to the tie rod 12 via the co-rotation preventing member 9 is integrally provided. The bellows 63 is made of, for example, a resin such as rubber or flexible plastic.

  One end 63 b of the bellows 63 is tightly fixed to the end 62 b of the housing 62 by tightening the bellows band 81. On the other hand, the other end 63c of the bellows 63 is fixed tightly to the tie rod 12 by tightening the bellows band 82. The bellows bands 81 and 82 are made of, for example, a stainless material.

  The co-rotation preventing member 9 is interposed between the other end 63c of the bellows 63 and the tie rod 12, and suppresses the rotation of the other end 63c of the bellows 63 accompanying the rotation of the tie rod 12. In the present embodiment, the co-rotation preventing member 9 is constituted by a bearing 90 that supports the other end portion 63 c of the bellows 63 on the outer peripheral surface of the tie rod 12. The bearing 90 includes an inner ring 91, an outer ring 92, a plurality of spherical rolling elements 93 that are rotatably held between the inner ring 91 and the outer ring 92, a cage 94 that holds the plurality of rolling elements 93, and an inner ring 91. And first and second seal members 95 and 96 disposed between the outer ring 92 and the outer ring 92.

  The first seal member 95 is disposed closer to the ball joint 7 than the rolling element 93, and the second seal member 96 is disposed on the opposite side. That is, the bearing 90 is a seal bearing in which the accommodation spaces of the plurality of rolling elements 93 are sealed by the first and second seal members 95 and 96.

  The inner ring 91 is fitted and fixed to the outer peripheral surface of the tie rod 12. One outer ring 92 is fitted and fixed to the inner peripheral surface of the other end portion 63 c of the bellows 63. The inner ring 91 and the outer ring 92 can smoothly rotate relative to each other by rolling of the rolling elements 93.

  On the outer peripheral surface of the tie rod 12, a small diameter stepped bearing support portion 122 that supports the bearing 90 is formed. On both sides in the axial direction of the bearing support portion 122, an annular step support surface 122a for supporting the bearing 90 and a ring groove 122b for inserting the retaining ring 10 are formed. The depth of the ring groove 122b is, for example, 2 to 3 mm. The inner ring 91 is fitted to the tie rod 12 from the end opposite to the ball head 121 and moves to the bearing support portion 122. The bearing support portion 122 is configured as a press-fit portion (tightening allowance) of the bearing 90, and the stepped support surface 122 a and the retaining ring 10 prevent the bearing 90 from coming off from the bearing support portion 122 in the axial direction.

  The bearing 90 is a member that prevents the bellows 63 from following and rotating with the rotation of the tie rod 12 at the time of toe-in adjustment for adjusting the length of the tie rod 12, for example. The circumferential displacement of the other end portion 63c with respect to the portion 63b is absorbed. Therefore, even if the tie rod 12 rotates, the other end 63c of the bellows 63 is supported by the bearing 90, so that the bellows 63 and the tie rod 12 do not rotate together. The rotation of the tie rod 12 can be generated not only during the toe-in adjustment but also by the turning of the steered wheel 11 by the rotation operation of the steering wheel 2. However, the bearing 90 absorbs the rotation of the tie rod 12 and the bellows. 63 torsion is suppressed.

[Effect of the embodiment]
According to the embodiment described above, the following effects can be obtained.

(1) Since the bearing 90 that absorbs the circumferential displacement of the other end 63c with respect to the one end 63b of the bellows 63 accompanying the rotation of the rack shaft 61 is provided, for example, grease is applied to the inner surface of the other end 63c of the bellows 63. By applying, it is possible to prevent the bellows 63 from rotating together with the tie rod 12 more reliably as compared with the case where the other end 63c of the bellows 63 and the tie rod 12 are rotated relative to each other. Moreover, it can suppress that the smoothness of the relative rotation of the bellows 63 and the tie rod 12 is impaired by aged deterioration or the like.

(2) Since it is not necessary to apply grease for lubrication or silicone rubber to the interface between the bellows 63 and the tie rod 12, it is possible to reduce the number of assembling steps. In addition, the bellows 63 and the tie rod 12 can be smoothly rotated relative to each other regardless of the presence or absence of surface treatment for the purpose of rust prevention or the like of the tie rod 12.

(3) Since the bearing 90 which is a seal bearing is used as the co-rotation preventing member 9, it is possible to prevent foreign substances from entering the inside of the bellows 63 and flooding.

[Modification]
Next, an end portion of the bellows 63 according to the modification of the embodiment of the present invention will be described with reference to FIG. FIG. 3 is a partial cross-sectional view showing an end portion of the bellows 63 according to this modification. 3, members having the same or equivalent functions as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  This modification is different from the above-described embodiment in that a small diameter stepped bearing support portion 122 that supports the bearing 90 is not formed on the outer peripheral surface of the tie rod 12. A bearing support portion 123 that press-fits and supports the inner ring 91 of the bearing 90 is formed on the shaft portion of the same diameter of the tie rod 12. On both sides in the axial direction of the bearing support portion 123, ring grooves 122b and 122b for accommodating a part of the retaining ring 10 are formed. The inner ring 91 is restricted from coming off the bearing 90 in the axial direction from the bearing support 123 by a pair of retaining rings 10 fitted in the ring grooves 122b and 122b, respectively.

  According to this modification, the pressing force when the inner ring 91 is moved from the end opposite to the ball head 121 to the bearing support portion 123 can be reduced, so that the assembly of the bearing 90 is facilitated. Can do.

  As mentioned above, although the steering device of the present invention was explained based on the above-mentioned embodiment, the present invention is not limited to the above-mentioned embodiment, and can be implemented in various modes without departing from the gist thereof. Is possible.

  For example, in the above embodiment, the case where a ball bearing using a spherical rolling element 93 is used as the bearing 90 has been described, but the present invention is not limited to this. As the bearing 90, for example, a needle roller bearing or a sliding bearing may be used.

  Moreover, although the said embodiment demonstrated the case where the inner ring | wheel 91 of the bearing 90 was provided in the outer peripheral surface of the tie rod 12 as one structural example of the co-rotation prevention member 9, it is not restricted to this. Instead of the inner ring 91 in which the inner peripheral rolling groove for rolling the rolling element 93 is formed, for example, the common rotation preventing member 9 in which the inner peripheral rolling groove is formed on the outer peripheral surface of the tie rod 12 may be used. In this case, the retaining ring 10 can be eliminated.

DESCRIPTION OF SYMBOLS 1 ... Steering device, 2 ... Steering wheel, 3 ... Steering shaft, 4 ... Steering assistance device, 5 ... Intermediate shaft, 6 ... Steering mechanism, 7 ... Ball joint, 9 ... Common rotation prevention member, 10 ... Retaining ring, 11 ... steered wheel, 12 ... tie rod, 30 ... steering column, 40 ... output shaft, 60 ... pinion shaft, 61 ... rack shaft (steered shaft), 62 ... housing, 62a ... main body, 62b ... end, 62c ... concave 63 ... Bellows, 63a ... Bellows part, 63b ... One end part, 63c ... Other end part, 70 ... Joint housing, 71 ... Main body part, 72 ... Screw part, 81, 82 ... Bellows band, 90 ... Bearing, 91 ... Inner ring , 92 ... Outer ring, 93 ... Rolling element, 94 ... Cage, 95 ... First seal member, 96 ... Second seal member, 120 ... Ball stud, 121 ... Ball head, 122, 123 ... Shaft Supporting portion, 122a ... stepped supporting surface, 122b ... ring groove, 601 ... pinion teeth, 610 ... female screw hole, 611 ... rack teeth 620 ... rack stopper 710 ... space

Claims (3)

A steered shaft that steers the steered wheel via a tie rod connected to the steered wheel of the vehicle;
A cylindrical housing for accommodating the steered shaft so as to be axially movable;
A ball joint connecting the end of the steered shaft and the tie rod;
A cylindrical bellows made of a stretchable resin having one end fixed to the housing and covering the ball joint;
A co-rotation preventing member interposed between the other end portion of the bellows and the tie rod, and suppressing rotation of the other end portion of the bellows accompanying rotation of the tie rod;
Steering device with The co-rotation preventing member is constituted by a bearing including an inner ring and an outer ring, and a plurality of rolling elements arranged so as to be able to roll between the inner ring and the outer ring,
The inner ring is fixed to the outer peripheral surface of the tie rod, and the outer ring is fixed to the inner peripheral surface of the bellows;
The steering apparatus according to claim 1. The bearing comprises a seal bearing having a seal member disposed between the inner ring and the outer ring.
The steering apparatus according to claim 2.

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