JP2019078309A - Boot attachment structure - Google Patents

Abstract

To provide a boot attachment structure which enables improvement of flexibility of a shape of an attachment object.SOLUTION: A boot 35 is attached to an opening end 32 of a cylindrical part 31 of a rack housing 13. An inner peripheral surface of the opening end 32 is formed with an annular recessed part 41 extending over an entire periphery of the inner peripheral surface. A connection end part 52 of the boot 35 includes: an inner periphery contact part 61 which contacts with an entire circumferential area of the inner peripheral surface of the opening end 32; a diameter expansion member 62 which expands a diameter of the inner periphery contact part 61 so as to press the inner periphery contact part 61 to the inner peripheral surface of the opening end 32; and an outer periphery contact part 63 which contacts with an entire circumferential area of an outer peripheral surface of the opening end 32. An annular protruding part 64 which protrudes to the inner peripheral surface of the opening end 32 and fits in the recessed part 41 is formed on an outer peripheral surface of the inner periphery contact part 61. The diameter expansion member 62 is fixed in the protruding part 64 in an embedded manner.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a mounting structure of a boot.

  2. Description of the Related Art Conventionally, there has been known a steering apparatus for a vehicle, which converts rotation of a steering shaft accompanying steering of a steering wheel into reciprocating movement of a rack shaft by a rack and pinion mechanism to change a steering angle of steered wheels. In such a steering device, the rack shaft is accommodated in a substantially cylindrical rack housing so as to be capable of reciprocating, and the steered wheels are connected to both ends thereof via tie rods.

  Here, in order to prevent foreign matter such as dust and rainwater from entering the rack housing, there are some which fix the both ends of the cylindrically formed boot to the open end of the rack housing and the tie rod. For example, in the steering apparatus disclosed in Patent Document 1, the large diameter cylindrical portion of the boot is fitted to the outer periphery of the open end of the rack housing, and the small diameter cylindrical portion of the boot is fitted to the outer periphery of the tie rod. The boot is fixed by mounting the.

JP, 2015-3607, A

  By the way, in the vicinity of the open end of the rack housing, a mount portion or the like for attaching the steering device to a vehicle member may be provided. On the other hand, in order to enhance the adhesion between the rack housing and the boot, it is desirable to finish the outer peripheral surface of the open end to a smooth surface by cutting or the like. Therefore, in order to secure a working area in which the tool to be finish-processed can be arranged in the vicinity of the outer periphery of the opening end, for example, it may be necessary to arrange the mount portion etc. at a position away from the opening end. Was a problem.

In addition, such a problem may arise similarly, not only when making a rack housing into attachment object of a boot, but when making an outer race of a constant velocity joint etc. into attachment object, for example.
An object of the present invention is to provide a boot attachment structure capable of enhancing the shape freedom of the attachment object.

  The attachment structure of the boot which solves the above-mentioned subject is attaching a cylindrical boot to the cylindrical part of attachment object, and the connection end of the boot to the cylindrical part is the opening end of the cylindrical part. An inner circumferential contact portion that contacts the inner circumferential surface over the entire circumferential direction, and an enlarged diameter member that expands the diameter so as to press the inner circumferential contact portion against the inner circumferential surface.

  According to the above configuration, the inward contact portion provided at the connection end of the boot is in close contact with the inner peripheral surface of the open end of the cylindrical portion, whereby the entry of foreign matter into the mounting object is prevented. Therefore, since the adhesion can be improved by finishing the inner peripheral surface of the opening end, it is not necessary to finish the outer peripheral surface of the opening end, and a tool for finishing near the outer periphery of the opening end is arranged It is not necessary to secure a possible work area. Thereby, for example, a mount portion or the like for attaching the attachment object to another member can be provided in the vicinity of the outer periphery of the opening end, and the shape freedom of the attachment object can be enhanced.

In the attachment structure of the boot described above, it is preferable that the enlarged diameter member be provided in a manner to be embedded in the inner circumferential contact portion.
According to the above configuration, for example, the assemblability of the boot can be improved as compared with the case where the diameter-expanding member is separately provided on the inner peripheral side of the inner peripheral contact portion.

  In the above-described structure for attaching a boot, a convex portion protruding toward the other is formed on either one of the inner peripheral surface of the open end and the outer peripheral surface of the inner peripheral contact portion, and the other is convex Preferably, a recess is formed in which the parts engage.

According to the above-mentioned configuration, it is possible to suppress the relative movement of the boot in the axial direction with respect to the mounting object by the convex portion engaging with the concave portion.
In the attachment structure of the boot described above, the connection end preferably includes an outer peripheral contact portion that abuts on an outer peripheral surface of the open end.

  According to the above configuration, the foreign matter can not reach between the inner circumferential contact portion and the opening end unless the inner circumferential outer circumferential contact portion is intruded into the attachment target. Can be suitably prevented.

  According to the present invention, it is possible to enhance the shape freedom of the mounting object.

The schematic block diagram of a steering device. (A) Partially sectional view which shows the attachment structure of the boot of one Embodiment, (b) is an expanded sectional view of the connection end part in a boot similarly. The expanded sectional view of the connection end in the boot of another example. The expanded sectional view of the connection end in the boot of another example. The expanded sectional view of the connection end in the boot of another example.

Hereinafter, an embodiment of a boot attachment structure will be described according to the drawings.
As shown in FIG. 1, the steering device 1 applies an assist force for assisting the steering operation to the steering mechanism 4 and a steering mechanism 4 that steers the steered wheels 3 based on an operation of the steering wheel 2 by the driver. And an EPS actuator 5.

  The steering mechanism 4 includes a steering shaft 11 to which the steering wheel 2 is fixed, a rack shaft 12 that reciprocates in the axial direction according to the rotation of the steering shaft 11, and a mounting target to which the rack shaft 12 is reciprocably inserted. And the rack housing 13 of FIG. The steering shaft 11 is configured by connecting the column shaft 11a, the intermediate shaft 11b, and the pinion shaft 11c sequentially from the steering wheel 2 side.

  The rack shaft 12 and the pinion shaft 11c are disposed in the rack housing 13 with a predetermined crossing angle, and the rack teeth 14 formed on the rack shaft 12 mesh with the pinion teeth 15 formed on the pinion shaft 11c. Thus, the rack and pinion mechanism 16 is configured. Tie rods 18 are rotatably connected to both ends of the rack shaft 12 via a rack end 17 formed of a ball joint provided at the shaft end. The tip of the tie rod 18 is connected to a knuckle (not shown) in which the steered wheels 3 are assembled. Therefore, in the steering device 1, the rotation of the steering shaft 11 accompanying the steering operation is converted to the axial movement of the rack shaft 12 by the rack and pinion mechanism 16, and this axial movement is transmitted to the knuckle via the tie rods 18. Thus, the turning angle of the turning wheel 3, that is, the traveling direction of the vehicle is changed.

  The EPS actuator 5 of the present embodiment converts the rotation transmitted through the transmission mechanism 22 that transmits the rotation of the motor 21 that is the drive source, the rotation of the motor 21 into the reciprocation of the rack shaft 12. And a ball screw mechanism 23. Then, the rotation of the motor 21 is transmitted to the ball screw mechanism 23 through the transmission mechanism 22, and the ball screw mechanism 23 converts the rotation into the reciprocating motion of the rack shaft 12 to apply an assist force to the steering mechanism 4. The EPS actuator 5 may be of a type that applies an assist force to the steering shaft 11, for example, or the steering device 1 may not include the EPS actuator 5.

  As shown in FIGS. 1 and 2A, a mount for attaching the steering device 1 to a vehicle member (not shown) in the vicinity of both open ends 32 of the axially extending cylindrical portion 31 in the rack housing 13 The portions 33 are formed respectively. Each mount portion 33 extends in a direction inclined with respect to the axial direction of the rack housing 13 so as to approach the open end 32 of the rack housing 13 as going radially outward of the cylindrical portion 31 and penetrates the tip end thereof Holes 34 are formed. The steering device 1 is mounted on the vehicle by being fastened to the vehicle member via bolts (not shown) through which the rack housings 13 are inserted into the respective through holes 34. Further, cylindrical boots 35 are attached to the open ends 32 on both axial sides of the cylindrical portion 31.

  Next, the mounting structure of the boot 35 will be described in detail. In addition, since the attachment structure of the boots 35 attached to the left and right ends of the rack housing 13 is configured symmetrically, only the attachment structure on the right side will be described, and the description of the attachment structure on the left side will be omitted. Further, for convenience of explanation, the left side in FIG. 2 is one end side in the axial direction, and the right side is the other end side in the axial direction.

  As shown to FIG. 2 (a), (b), the rack housing 13 consists of metal materials, such as an aluminum alloy, and is manufactured by casting. The open end 32 of the rack housing 13 is formed in a cylindrical shape. The inner peripheral surface of the opening end 32 is subjected to finish processing such as cutting, and is finished to a smooth surface. On the other hand, the outer peripheral surface of the opening end 32 is not subjected to finish processing, and is a slightly rough surface in a state of being taken out of the mold. The inner peripheral surface of the open end 32 is formed with an annular recess 41 extending along the entire circumference thereof. The concave portion 41 is formed in a substantially rectangular cross-sectional shape in which the bottom portion and the opening portion are chamfered. A damper 36 is provided on the inner peripheral surface of the open end 32 to reduce the impact when the rack end 17 collides. An annular ridge 42 is formed on the outer peripheral surface of the open end 32 and extends around the entire circumference.

  The boot 35 is made of an elastic material such as rubber or resin, and formed in a substantially cylindrical shape. The boot 35 includes an encircling portion 51, a connecting end portion 52 provided on one end side in the axial direction of the encircling portion 51, and a small diameter cylindrical portion 53 provided on the other end side in the axial direction of the encircling portion 51.

  The surrounding portion 51 is formed in a bellows shape, and surrounds the connecting portion between the rack shaft 12 and the tie rod 18. The small diameter cylindrical portion 53 is formed in a cylindrical shape having an inner diameter substantially equal to the outer diameter of the tie rod 18, and is fitted to the outer periphery of the tie rod 18. A boot band 54 is attached to the outer periphery of the small diameter cylindrical portion 53. As a result, the small diameter cylindrical portion 53 is in close contact with the tie rod 18 and is sealed so that foreign substances such as dust and rain water do not enter between them.

  The connecting end portion 52 is expanded in diameter so as to press the inner circumferential contact portion 61 which contacts the inner circumferential surface of the open end 32 over the entire circumferential direction and the inner circumferential contact portion 61 against the inner circumferential surface of the open end 32. And an outer peripheral contact portion 63 which is in contact with the outer peripheral surface of the open end 32 over the entire circumferential direction.

  The inner circumferential contact portion 61 is formed in a cylindrical shape having an outer diameter substantially equal to the inner diameter of the open end 32. The outer peripheral surface of the inner peripheral contact portion 61 is formed with a convex portion 64 which extends over the entire periphery and protrudes toward the inner peripheral surface of the opening end 32. The cross-sectional shape of the convex portion 64 is formed in accordance with the cross-sectional shape of the concave portion 41, and is fitted to the concave portion 41. The diameter expanding member 62 employs a garter spring formed in an endless annular shape. When the boot 35 is manufactured by injection molding or the like, the enlarged diameter member 62 is disposed at a position corresponding to the convex portion 64, and is fixed to the inner circumferential contact portion 61 in a manner to be embedded. The outer diameter of the enlarged diameter member 62 is set larger than the inner diameter of the bottom surface portion of the recess 41 in the natural state. Then, in a state where the inner circumferential contact portion 61 is fitted to the inner circumferential surface of the opening end 32 and the convex portion 64 is fitted to the concave portion 41, the diameter expansion member 62 is in a compressed state, and the inner circumferential contact portion 61 is expanded. The diameter is pressed against the inner peripheral surface of the open end 32. As a result, the inner circumferential contact portion 61 is in close contact with the inner circumferential surface of the open end 32 and is sealed so that foreign matter does not enter between the two.

  The outer circumferential contact portion 63 is formed in a cylindrical shape extending radially outward from the connection portion between the surrounding portion 51 and the inner circumferential contact portion 61 and then extending to one axial end side. The inner diameter of the outer circumferential contact portion 63 is set to be substantially equal to the outer diameter of the open end 32. An annular annular groove 65 extending over the entire circumference is formed on the inner peripheral surface of the outer peripheral contact portion 63, and the annular groove 65 is engaged with the protrusion 42.

As described above, according to this embodiment, the following effects can be achieved.
(1) The connection end portion 52 of the boot 35 is provided with the inner circumferential contact portion 61 that contacts the inner circumferential surface of the open end 32 over the entire circumferential direction, and the inner circumferential contact portion 61 is expanded by the diameter increasing member 62 The boot 35 was attached to the rack housing 13 by pressing it against the inner peripheral surface of the open end 32. Then, the inner peripheral contact portion 61 is in close contact with the inner peripheral surface of the opening end 32 so that the entry of foreign matter into the rack housing 13 is prevented. Therefore, the adhesion can be improved by finishing the inner peripheral surface of the opening end 32. Therefore, it is not necessary to finish the outer peripheral surface of the opening end 32, and finish processing is performed near the outer periphery of the opening end 32. It is not necessary to secure a work area where tools can be placed. Thereby, the mount portion 33 can be provided in the vicinity of the outer periphery of the open end 32, and the degree of freedom in shape of the rack housing 13 can be enhanced while securing the sealability by the boot 35.

  (2) Since the enlarged diameter member 62 is embedded in the inner circumferential contact portion 61, the boot 35 can be assembled with one touch by pushing the boot 35 in the axial direction in the axial direction. As compared with the case of providing separately on the inner circumferential side of the circumferential contact portion 61, the assemblability of the boot 35 can be improved.

  (3) The annular convex portion 64 is formed on the outer peripheral surface of the inner peripheral contact portion 61, and the annular concave portion 41 in which the convex portion 64 is engaged is formed on the inner peripheral surface of the opening end 32. Relative movement in the axial direction with respect to the rack housing 13 can be suitably suppressed.

  (4) The connection end portion 52 is provided with the outer peripheral contact portion 63 that contacts the outer peripheral surface of the open end 32 over the entire circumferential direction. It can not reach between the inner circumferential contact portion 61 and the open end 32. Thereby, it is possible to preferably prevent the entry of foreign matter into the rack housing 13.

In addition, the said embodiment can also be implemented in the following aspects which changed this suitably.
In the above embodiment, the outer circumferential contact portion 63 is formed in a cylindrical shape, but is not limited to this. For example, the outer circumferential contact portion 63 may be formed in an arc plate shape extending over a partial range in the circumferential direction. Further, for example, as shown in FIG. 3, the outer peripheral contact portion 63 may not be provided at the connection end 52.

  In the above embodiment, the boot band 71 may be attached to the outer circumferential side of the outer circumferential contact portion 63 as shown in FIG. 4, for example. With this configuration, it is possible to more preferably prevent the entry of foreign matter into the rack housing 13. In addition, since the space between the inner peripheral contact portion 61 and the inner peripheral surface of the open end 32 is sealed, the outer peripheral surface of the open end 32 may remain rough.

  In the embodiment described above, the recess 41 is formed in an annular shape, but is not limited to this. For example, the recess 41 may be formed in an arc extending over a partial range in the circumferential direction. In this case, the convex portion 64 may be formed, for example, in the shape of a ridge extending over a partial range in the circumferential direction. Alternatively, the convex portion may be formed on the inner circumferential surface of the opening end 32 and the concave portion may be formed on the outer circumferential surface of the inner circumferential contact portion 61. Furthermore, the recess 41 and the protrusion 64 may not be formed. In addition, such a deformation is applicable to the ridges 42 and the annular groove 65 in the same manner.

  In the above embodiment, the garter spring is used as the enlarged diameter member 62. However, the present invention is not limited to this. For example, a C-shaped wire spring may be used. In this case, in a state where the boot 35 is attached to the rack housing 13, it is preferable that the ends of the wire springs be in a compressed state as close as possible.

  In the above embodiment, the diameter increasing member 62 is fixed in the convex portion 64. However, the present invention is not limited to this. For example, the diameter expanding member 62 may be provided at an axial position different from the convex portion 64 in the inner circumferential contact portion 61. It can be changed as appropriate. In addition, the diameter expanding member 62 is not embedded in the inner peripheral contact portion 61, and as shown in FIG. 5, for example, the inner peripheral surface of the inner peripheral contact portion 61 is a diameter expanded member 72 formed of a C-shaped wire spring or the like. You may arrange | position in the inside so that it may contact.

The attachment structure of the above embodiment may be applied when attaching the boot 35 to another attachment object such as an outer race of a constant velocity joint, for example.
Next, technical ideas that can be grasped from the above-described embodiment and another example will be additionally described below together with their effects.

  (A) The attachment structure of the boot formed in an annular shape extending in the circumferential direction of the opening end and the inner circumferential contact portion, respectively. According to the above configuration, relative movement of the boot relative to the mounting target in the axial direction can be suitably suppressed.

  DESCRIPTION OF SYMBOLS 1 ... Steering apparatus, 4 ... Steering mechanism, 11 ... Steering shaft, 12 ... Rack axis, 13 ... Rack housing (object of attachment) 17 ... Rack end, 18 ... Tie rod, 31 ... Tubular part, 32 ... Opening end, 33 ... Mount portion 35 boot 41 concave portion 42 protrusion 51 encircling portion 52 connection end 53 small diameter cylindrical portion 54, 71 boot band 61 inner circumferential contact portion 62 ... Expanded diameter member, 63 ... outer peripheral contact portion, 64 ... convex portion, 65 ... annular groove.

Claims (4)

It is the attachment structure of the boot which attaches a cylindrical boot to the cylindrical part of attachment object,
The connection end portion of the boot with respect to the cylindrical portion has an inner circumferential contact portion that contacts the inner circumferential surface of the open end of the cylindrical portion over the entire circumferential direction, and the inner circumferential contact portion is the inner circumferential contact portion And a mounting structure of the boot including a diameter-increasing member for expanding the diameter so as to press against the surface. In the boot attachment structure according to claim 1,
The mounting structure of a boot provided in a mode in which the diameter expansion member is embedded in the inner circumferential contact portion. In the boot attachment structure according to claim 1 or 2,
A convex portion protruding toward the other is formed on one of the inner peripheral surface of the opening end and the outer peripheral surface of the inner peripheral contact portion, and a concave portion with which the convex portion is engaged is formed on the other. Mounting structure of the formed boot. In the boot attachment structure according to any one of claims 1 to 3,
The attachment structure of a boot including the outer peripheral contact portion in which the connection end portion is in contact with an outer peripheral surface of the open end.