JP6965691B2 - Seal ring, cross shaft joint and steering device - Google Patents

Description

The present application relates to a seal ring incorporated in a cross shaft joint used for a shaft connecting portion that transmits a steering force of a steering device, a cross shaft joint provided with the seal ring, and a steering device provided with the cross shaft joint. be.

Conventionally, there is a seal ring that seals a gap formed between a bearing cup of a radial bearing that is externally fitted to the end of a cross shaft constituting a cross shaft joint and a shaft portion of the cross shaft.

Such a seal ring has an elastic seal portion and a reinforcing ring embedded in the elastic seal portion, as in Patent Document 1 below.

Utility Model Registration No. 3041732

When molding the elastic seal portion described in Patent Document 1, it is necessary to position the reinforcing ring inside the mold, but when the entire reinforcing ring is embedded in the elastic seal portion, the reinforcing ring may be brought into contact with the mold. It cannot be done and the moldability is poor.

Further, when a part of the reinforcing ring is brought into contact with the mold for positioning, the elastic seal portion is not fixed to the portion of the reinforcing ring in contact with the mold, and the reinforcing ring is exposed, so that the sealing property may be deteriorated. There is.

In view of the above, it is an object of the present invention to provide a seal ring, a cross shaft joint and a steering device having excellent moldability and sealability.

In order to solve the above problems, the present application has a central portion and four shaft portions extending from the central portion in four directions, respectively, and the central portion is in the radial direction of the shaft portion from the base end of the shaft portion. Used with a cross axis that forms a stepped surface that extends outward
A seal ring that is externally fitted to the shaft portion and is arranged between the radial bearing attached to the tip end portion of the shaft portion and the stepped surface.
With a ring-shaped core metal
It has an elastic portion fixed to the core metal and has an elastic portion.
The elastic portion has a bearing-side seal lip that contacts the radial bearing over the entire circumference.
The core metal is radially outward from the cylindrical portion through which the shaft portion is passed radially inside the shaft portion and the end portion of the cylindrical portion on the stepped surface side in the central axis direction of the shaft portion. Has an extending slope and
The inclined portion is inclined so as to approach the radial bearing side in the central axis direction of the shaft portion as it goes outward in the radial direction of the shaft portion.
The inclined portion has a penetrating portion penetrating in the direction of the central axis of the shaft portion.
The elastic portion is fixed to the radial bearing side and the stepped surface side of the inclined portion in the direction of the central axis of the shaft portion.
The portion of the elastic portion on the radial bearing side and the stepped surface side is integrally formed through the penetrating portion .
Provided is a seal ring characterized in that the outer end of the inclined portion and the stepped surface side end of the core metal are exposed.

Preferably, the penetrating portion is a recess recessed from the radial outer side to the radial inner side of the shaft portion.

Further, preferably, the penetrating portion is a hole portion.

Further, preferably, the elastic portion has a seal lip on the stepped surface side that protrudes in an annular shape on the stepped surface side.

Further, preferably, the inclined portions are arranged at substantially equal intervals in the circumferential direction, and have three or more outer ends arranged on the outermost side in the radial direction.

Further, in order to solve the above-mentioned problems, the present application provides a cross-shaped shaft joint characterized by providing the above-mentioned seal ring.

Further, in order to solve the above problems, the present application provides a steering device including the above-mentioned 10 o'clock shaft joint.

In view of the above, it is an object of the present invention to provide a seal ring, a cross shaft joint and a steering device having excellent moldability and sealability.

FIG. 1 is a side view showing a steering device according to an embodiment of the present application. FIG. 2 is a perspective view showing an intermediate shaft and a cross shaft joint according to the embodiment of the present application. FIG. 3 is a cross-sectional view of a cross shaft, a radial bearing, and a seal ring according to an embodiment of the present application. FIG. 4 is an enlarged cross-sectional view of the periphery of the seal ring according to the first embodiment of the present application. FIG. 5 is a cross-sectional view of the seal ring according to the first embodiment of the present application. FIG. 6A is a plan view showing the core metal of the seal ring according to the first embodiment of the present application. FIG. 6B is a cross-sectional view of the core metal according to the first embodiment of the present application on the XX cut surface shown in FIG. 6A. FIG. 7A is a plan view showing the core metal of the seal ring according to the second embodiment of the present application. FIG. 7B is a cross-sectional view of the seal ring according to the second embodiment of the present application on the YY cut surface shown in FIG. 7A. FIG. 8A is a plan view showing the core metal of the seal ring according to the third embodiment of the present application. FIG. 8B is a cross-sectional view of the seal ring according to the third embodiment of the present application on the ZZ cut surface shown in FIG. 8A.

Hereinafter, embodiments of the present application will be described with reference to the drawings. FIG. 1 is a side view showing a steering device 100 common to the first to third embodiments of the present application.

As shown in FIG. 1, the steering device 100 includes a steering wheel 1, a steering shaft 2, a steering column 3, a vehicle body side bracket 4, a first cross shaft joint 5, an intermediate shaft 6, and a second. It has a cross shaft joint 7, a pinion gear 8, and a rack shaft 9. The steering wheel 1 is fixed to a steering shaft 2 that transmits its rotation. The steering shaft 2 passes through the inside of the steering column 3 and is rotatably supported by the steering column 3 about the central axis. The steering column 3 is attached to the vehicle body 200 by the vehicle body side bracket 4. The rotation of the steering shaft 2 is transmitted to the intermediate shaft 6 by the first cross shaft joint 5. The rotation of the intermediate shaft 6 is transmitted to the pinion gear 8 by the second cross shaft joint 7. The pinion gear 8 rotates to move the rack shaft 9 in the vehicle width direction. The rack shaft 9 moves a knuckle arm (not shown) via a tie rod (not shown) to steer a front wheel (not shown).

FIG. 2 is a perspective view showing an intermediate shaft 6, a first cross-shaped joint 5, and a second cross-shaped joint 7, which are common to the first to third embodiments of the present application.

The first cross-shaped joint 5 includes a first yoke 11 and a second yoke 12. The second cross-shaped joint 7 includes a third yoke 13 and a fourth yoke 14. The first yoke 11 has a pair of arms 11a formed in a bifurcated shape. The second yoke 12 has a pair of arms 12a formed in a bifurcated shape. The first yoke 11 and the second yoke 12 are connected via a pair of arms 11a and a cross shaft 16 described later held by the pair of arms 12a. Similarly, the third yoke 13 and the fourth yoke 14 are also connected by a cross shaft 16 described later, which is held by a pair of arms 13a and a pair of arms 14a.

FIG. 3 is a cross-sectional view of the cross shaft 16, the radial bearing 21, and the seal ring 26 that are common to the first to third embodiments of the present application. A cross section cut in a direction perpendicular to the central axis of the intermediate shaft 6 is shown.

The cross shaft 16 has a central portion 17 and four columnar shaft portions 18 extending from the central portion 17 in four directions, respectively. Specifically, the cross axis 16 includes a first shaft portion 18 extending in one direction from the central portion 17, and a first shaft portion 18 and a first shaft portion 18 having the same central axis as the first shaft portion 18. A second shaft portion 18 extending to the opposite side, a third shaft portion 18 extending from the center portion 17 in a direction perpendicular to the first and second shaft portions 18, and a third shaft portion 18 and a center. It has a fourth shaft portion 18 extending from the central portion 17 to the side opposite to the third shaft portion 18 in common with the axis line. Since the configuration around the shaft portion 18 is common to the four shaft portions 18, only one location will be described, and the description of the configuration around the other shaft portions 18 will be omitted. A radial bearing 21 is fitted on the tip of the shaft portion 18. As the radial bearing 21, a needle bearing can be used. The radial bearing 21 has a bearing cup 22 and a roller 23. The bearing cup 22 is fitted in the circular holes formed in the pair of arms 11a to 14a of the yokes 11 to 14 described above. A plurality of rollers 23 are arranged between the bearing cup 22 and the shaft portion 18 of the cross shaft 16 in a direction substantially parallel to the shaft portion 18 in the circumferential direction.

An insertion hole 18a is formed in the central portion of the shaft portion 18 from the tip end side toward the base portion side. A synthetic resin pin 24 is inserted inside the insertion hole 18a. A seal ring 26 is fitted on the base of the shaft portion 18. The seal ring 26 prevents foreign matter from entering the radial bearing 21 through the gap between the bearing cup 22 and the shaft portion 18. The pin 24 is interposed between the bearing cup 22 and the shaft portion 18 to prevent the bearing cup 22 from moving toward the base portion of the shaft portion 18. As a result, it is possible to prevent the seal ring 26 from being compressed by the bearing cup 22 and impairing the sealability. The seal ring 26 does not have to be provided in the cross shaft joint provided in the vehicle interior as in the first cross shaft joint 5 shown in FIG.

FIG. 4 is an enlarged cross-sectional view of the periphery of the seal ring 26 according to the embodiment of the present application. The portion shown in FIG. 4 has the same cross-sectional shape over the entire circumference.

The seal ring 26 has a core metal 127 and an elastic portion 28. The core metal 127 is made of metal and has a ring shape. The elastic portion 28 is made of an elastomer and is fixed to the core metal 127. The elastic portion 28 also has a circular ring shape. The central portion 17 of the cross shaft 16 has a larger dimension than the shaft portion 18 in the radial direction of the shaft portion 18, and forms a stepped surface 17a extending radially outward from the base end of the shaft portion 18. There is. The stepped surface 17a is arranged at a substantially right angle to the central axis of the shaft portion 18. The elastic portion 28 comes into contact with the bearing cup 22 and the stepped surface 17a to prevent foreign matter such as muddy water from entering the bearing cup 22.

(First Embodiment)
FIG. 5 is a cross-sectional view of the seal ring 26 according to the first embodiment of the present application. The seal ring 26 has a similar cross-sectional shape over the entire circumference.

The core metal 127 can be formed by bending a metal plate. The core metal 127 has a cylindrical portion 127a having a cylindrical shape on the inner side in the radial direction, and an inclined portion 127b extending radially outward from the outer circumference of the cylindrical portion 127a. The inclined portion 127b is inclined so as to approach the radial bearing 21 side in the central axis direction toward the outer side in the radial direction, and is inclined in the cross section of the core metal 127 cut in the central axis direction and the radial direction of the shaft portion 18. The angle formed by the portion 127b and the cylindrical portion 127a is a sharp angle. As a result, a part of the elastic portion 28 can be arranged between the inclined portion 127b and the stepped surface 17a, and the sealing performance between the inclined portion 127b and the stepped surface 17a can be improved.

The elastic portion 28 has a cross-sectional shape shown in FIG. 5 when it is not attached to the cross shaft 16. The elastic portion 28 includes a main body 29, a first seal lip 31 on the bearing side, a second seal lip 32 on the bearing side, a third seal lip 33 on the bearing side, and a fourth seal lip 33 on the step surface 17a side. It has a seal lip 34. The main body 29 of the elastic portion 28 is fixed to the entire surface of the core metal 127 except for the outer end 127c in the radial direction of the inclined portion 127b and the stepped surface side end 127d on the stepped surface 17a side in the central axis direction of the shaft portion 18. doing. The outer end 127c and the stepped surface side end 127d to which the main body 29 is not fixed are exposed and can be used for positioning the core metal 127 by contacting the mold when molding the elastic portion 28. In particular, the radial outer end 127c of the inclined portion 127b can be used for automatic centering of the core metal 127 by hitting the mold during molding of the elastic portion 28.

The main body 29 of the elastic portion 28 extends radially outward from the core metal 127 over the entire circumference, and rises toward the radial bearing 21 side (upper side in FIG. 5) in the central axial direction of the shaft portion 18. The first seal lip 31 projects radially inward over the entire circumference from the portion of the main body 29 located closest to the radial bearing 21 side in the central axis direction of the shaft portion 18. As shown in FIG. 4, the first seal lip 31 is pressed against the outer peripheral surface of the bearing cup 22.

The second seal lip 32 protrudes inward in the radial direction from the portion of the main body 29 near the first seal lip 31 between the core metal 127 and the first seal lip 31. The second seal lip 32 has a conical surface shape that is inclined with respect to the central axis of the shaft portion 18 so that the inner diameter and the outer diameter become smaller toward the radial bearing 21 side in the direction of the central axis of the shaft portion 18. There is. As shown in FIG. 4, the second seal lip 32 is pressed against the outer peripheral surface of the bearing cup 22 of the radial bearing 21.

The third seal lip 33 projects from the portion of the main body 29 on the radial bearing 21 side of the core metal 127 in the central axis direction of the shaft portion 18 to the radial bearing 21 side over the entire circumference. The third seal lip 33 has a conical surface shape that is inclined with respect to the central axis of the shaft portion 18 so that the inner diameter and the outer diameter increase toward the radial bearing 21 side in the axial direction of the shaft portion 18. As shown in FIG. 4, the third seal lip 33 is pressed against the inner curved portion 22a of the bearing cup 22.

The fourth seal lip 34 on the stepped surface 17a side is annular from the elastic body 28 on the stepped surface 17a side in the direction of the central axis of the shaft portion 18 to the central portion 17 side (lower side in FIG. 5) of the cross shaft 16. It protrudes into. The fourth seal lip 34 is arranged radially outside the step surface side end 127d of the core metal 127. The fourth seal lip 34 projects toward the central portion 17 of the cross shaft 16 from the stepped surface side end 127d of the core metal 127 in the central axis direction of the shaft portion 18, but as shown in FIG. 4, the cross shaft In the state of being attached to 16, it is elastically deformed, and the stepped surface side end 127d comes into contact with the stepped surface 17a.

FIG. 6A is a plan view showing a core metal 127 of the seal ring 26 according to the first embodiment of the present application. FIG. 6B is a cross-sectional view of the core metal 127 according to the first embodiment of the present application on the XX cut surface shown in FIG. 6A.

The inclined portion 127b of the core metal 127 has a plurality of recesses 127e recessed inward in the radial direction at regular intervals in the circumferential direction. The recess 127e forms a penetrating portion that penetrates the inclined portion 127b in the central axis direction, and is formed on the elastic portion 28 portion of the inclined portion 127b on the radial bearing 21 side and the stepped surface 17a side of the inclined portion 127b. It plays a role of integrating the arranged elastic portion 28. In the present embodiment, the number of recesses 127e is eight, but the number of recesses 127e is not limited to this. Further, the size and shape of the recess 127e are not limited to those shown in the present embodiment. Any number, size, and shape of the recess 127e can be selected as long as it serves as a penetrating portion as described above.

(Second Embodiment)
Next, the second embodiment of the present application will be described with reference to FIGS. 7 (a) and 7 (b). FIG. 7A is a plan view showing a core metal 227 of the seal ring according to the second embodiment. FIG. 7B is a cross-sectional view of the seal ring according to the second embodiment on the YY cut surface shown in FIG. 7A. In the second embodiment, a part of the shape of the core metal 227 is different from that of the first embodiment, and other configurations are the same as those of the first embodiment. Therefore, the description of the same parts as those of the first embodiment will be omitted, and the parts different from those of the first embodiment will be described. For the portion corresponding to the portion of the first embodiment, a reference code of the number obtained by adding "100" to the reference code of the first embodiment is used. For example, the cylindrical portion of the second embodiment corresponding to the cylindrical portion 127a of the first embodiment will be described with "227a".

The core metal 227 of the second embodiment forms a plurality of elongated holes 227f long in the circumferential direction in the inclined portion 227b instead of the recess 127e of the first embodiment. The elongated hole 227f is a penetrating portion that penetrates the inclined portion 227b in the central axis direction, and is arranged on the portion of the elastic portion 28 arranged on the radial bearing 21 side of the inclined portion 227b and on the stepped surface 17a side of the inclined portion 227b. It plays a role of integrating the elastic portion 28. The penetrating portion is not limited to the elongated hole 227f shown in FIG. 7 as long as it is a hole in which the elastic portion 28 can be integrally formed. For example, in the present embodiment, the number of elongated holes 227f is set to 6, but the number of elongated holes 227f is not limited to this, and may be 5 or less, or 7 or more. Further, the size and shape of the elongated hole 227f are not limited to those shown in FIG. 7, and may be a round hole or a square hole instead of the elongated hole.

(Third Embodiment)
Next, the third embodiment of the present application will be described with reference to FIGS. 8 (a) and 8 (b). FIG. 8A is a plan view showing a core metal 327 of the seal ring according to the third embodiment. FIG. 8B is a cross-sectional view of the seal ring according to the third embodiment on the ZZ cut surface shown in FIG. 8A. In the third embodiment, a part of the shape of the core metal 327 is different from that of the first embodiment, and other configurations are the same as those of the first embodiment. Therefore, the description of the same parts as those of the first embodiment will be omitted, and the parts different from those of the first embodiment will be described. For the portion corresponding to the portion of the first embodiment, a reference code of the number obtained by adding "200" to the reference code of the first embodiment is used. For example, the cylindrical portion of the third embodiment corresponding to the cylindrical portion 127a of the first embodiment will be described with "327a".

In the core metal 327 of the third embodiment, instead of the outer end 127c of the first embodiment, the tips of three square protrusions 327g separated at substantially equal intervals in the circumferential direction are centered along the radial direction. The outer end 327c is located at the farthest position from. The square projecting portion 327g is formed so that the radial outer portion of the inclined portion 327b is projected at the center by two linear sides. The outer ends 327c separated at substantially equal intervals in the circumferential direction can be applied to the mold when the elastic portion 28 is molded, so that the core metal 327 can be automatically centered with higher accuracy. If three or more outer ends 327c separated in the circumferential direction can be arranged so that the core metal 327 can be automatically aligned in this way with high accuracy, FIG. 8 (a) shows. It is not limited to the square protrusion 327 g shown. For example, in the portion of the inclined portion 327b separated at substantially equal intervals in the circumferential direction, the curvature of the end portion on the outer side in the radial direction may be higher than that in the other portion so as to project outward in the radial direction. ..

According to the above embodiment of the present application, it is possible to provide a seal ring, an intermediate shaft and a steering device having excellent moldability and sealability.

The invention of the present application is not limited to the above embodiment. For example, instead of the pin 24, a protrusion protruding toward the shaft portion 18 may be provided at the center of the bottom of the bearing cup 22 facing the end surface of the shaft portion 18, and the shaft portion 18 may not be provided with the insertion hole 18a.

Further, the number of seal lips of the seal ring 26 is not limited to four, and it is sufficient that there are a seal lip that contacts the central portion 17 of the cross shaft 16 and a seal lip that contacts the bearing cup 22, and even two, three, or five. It may be one or more.

Further, the penetrating portion may include both the recess portion described in the first and third embodiments and the hole portion described in the second embodiment.

1 Steering wheel 2 Steering shaft 3 Steering column 4 Body side bracket 5 First cross shaft joint 6 Intermediate shaft 7 Second cross shaft joint 8 Pinion gear 9 Rack shaft 11 First yoke 12 Second yoke 13 Third Yoke 14 Fourth yoke 11a, 12a, 13a, 14a Pair of arms 16 Cross shaft 17 Center 17a Stepped surface 18 Shaft 18a Insertion hole 21 Radial bearing 22 Bearing cup 23 Roller 24 Pin 26 Seal ring 28 Elastic part 29 Main body 31 1st seal lip 32 2nd seal lip 33 3rd seal lip 34 4th seal lip 100 Steering device 127, 227, 327 Core metal 127a Cylindrical part 127b, 227b Inclined part 127c, 327c Outer end 127d Step surface side Edge 127e, 327e Recess 227f Long hole 327g Square protrusion 200 Car body

Claims (7)

A cross having a central portion and four shaft portions extending from the central portion in four directions, respectively, and the central portion forming a stepped surface extending radially outward from the base end of the shaft portion. Used with the shaft
A seal ring that is externally fitted to the shaft portion and is arranged between the radial bearing attached to the tip end portion of the shaft portion and the stepped surface.
With a ring-shaped core metal
It has an elastic portion fixed to the core metal and has an elastic portion.
The elastic portion has a bearing-side seal lip that contacts the radial bearing over the entire circumference.
The core metal is radially outward from the cylindrical portion through which the shaft portion is passed radially inside the shaft portion and the end portion of the cylindrical portion on the stepped surface side in the central axis direction of the shaft portion. Has an extending slope and
The inclined portion is inclined so as to approach the radial bearing side in the central axis direction of the shaft portion as it goes outward in the radial direction of the shaft portion.
The inclined portion has a penetrating portion penetrating in the direction of the central axis of the shaft portion.
The elastic portion is fixed to the radial bearing side and the stepped surface side of the inclined portion in the direction of the central axis of the shaft portion.
The portion of the elastic portion on the radial bearing side and the stepped surface side is integrally formed through the penetrating portion .
A seal ring characterized in that the outer end of the inclined portion and the stepped surface side end of the core metal are exposed. The seal ring according to claim 1, wherein the penetrating portion is a recess recessed from the outer side in the radial direction to the inner side in the radial direction. The seal ring according to claim 1, wherein the penetrating portion is a hole portion. The seal ring according to any one of claims 1 to 3, wherein the elastic portion has a seal lip on the step surface side that protrudes annularly on the step surface side. The aspect according to any one of claims 1 to 4, wherein the inclined portions are arranged at substantially equal intervals in the circumferential direction and have three or more outer ends arranged on the outermost side in the radial direction. Seal ring. A cross shaft joint comprising the seal ring according to any one of claims 1 to 5. A steering device including the cross shaft joint according to claim 6.

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