JP2019086010A - Seal ring and telescopic shaft - Google Patents

Abstract

To provide a seal ring structure that can prevent generation of rust at a core metal and secure support rigidity against an outer tube.SOLUTION: In a core metal 7a constituting a seal ring 6a, a covering part 27 constituting an elastomer 8a covers the whole circumferences of: an outer peripheral surface of a fixed cylinder part 9a that is externally fitted and fixed to an outer peripheral surface of an end part of an outer tube 3a; and the other side surface in an axial direction of an inward flange part 10a curved inward in a radial direction from an axial end part of the fixed cylinder part 9a.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a seal ring used in an environment exposed to the open air, and a telescopic shaft used as, for example, an intermediate shaft that constitutes a steering apparatus of an automobile.

  In a steering apparatus for an automobile, a front end portion of a steering shaft having a steering wheel attached to a rear end portion and a pinion shaft constituting a steering gear unit are connected via an intermediate shaft. As an intermediate shaft incorporated in such a steering device, the overall length can be extended or reduced in order to prevent the vibration input from the wheel during traveling from being transmitted to the steering wheel, or in consideration of the assembling workability to the vehicle body It may use the one of different structure.

  FIG. 6 shows the conventional structure of the telescopic intermediate shaft 1 described in JP-A-2005-195120. The intermediate shaft 1 is provided with a hollow cylindrical outer tube 3 having a female spline portion 2 formed on the inner peripheral surface, and an inner shaft 5 having a male spline portion 4 formed on the outer peripheral surface. The outer tube 3 and the inner shaft 5 are combined so as to be able to transmit torque and to be expandable and contractible by spline engagement of the female spline portion 2 and the male spline portion 4.

  Further, a seal ring 6 is incorporated in the intermediate shaft 1 in order to prevent foreign matter such as rain water and muddy water from entering the spline engaging portion between the female spline portion 2 and the male spline portion 4. The seal ring 6 includes a metal cored bar 7 and an elastic member 8 fixed to the cored bar 7. Among them, the core metal 7 has a cylindrical fixed cylindrical portion 9 and an inwardly directed flange portion 10 bent at a right angle radially inward from an axial end of the fixed cylindrical portion 9. Such a core metal 7 is attached to the outer tube 3 by externally fixing the fixed cylindrical portion 9 to the outer peripheral surface of the axial direction end of the outer tube 3. The elastic member 8 is fixed to the inner peripheral edge portion of the inward flange portion 10 constituting the core metal 7 and has a seal lip portion 11 whose tip edge is in contact with the outer peripheral surface of the inner shaft 5.

  According to the conventional structure as described above, since the tip end edge of the seal lip portion 11 is in sliding contact with the outer peripheral surface of the inner shaft 5 even when the intermediate shaft 1 is expanded or contracted, the end opening of the outer tube 3 is closed. be able to. Therefore, foreign matter such as rain water or muddy water can be prevented from entering the spline engaging portion between the female spline portion 2 and the male spline portion 4.

JP, 2005-195120, A Unexamined-Japanese-Patent No. 2003-161331 WO 2003/031250 pamphlet

  However, in the conventional structure described above, most of the metal core metal 7 is exposed to the outside, so when the intermediate shaft 1 is used outside the vehicle, salt water or muddy water adheres to the outer surface of the metal core 7 The core metal 7 is likely to be rusted. In addition, when rusting occurs on the cored bar 7, rusting easily progresses to the outer tube 3 in contact with the cored bar 7 (so-called rusting tends to occur).

  Therefore, as described in JP-A-2003-161331, it is conceivable to cover the entire surface of the cored bar with an elastic material. By adopting such a structure, it is possible to effectively prevent the occurrence of rusting on the core metal and thus on the outer tube. However, when the entire surface of the metal core is covered with the elastic material in this manner, the support rigidity of the seal ring with respect to the outer tube becomes low, making it difficult to stabilize the contact state between the seal lip and the outer peripheral surface of the inner shaft. .

  The present invention has been made in view of the above-described circumstances, and an object thereof is to realize a seal ring structure capable of preventing rusting of a core metal and securing support rigidity to an outer tube. It is to be.

The seal ring of the present invention is incorporated in a telescopic shaft formed by combining a hollow cylindrical female shaft and a male shaft so as to be able to transmit torque and extend its entire length, and is made of a metal core metal, And an elastic member fixed to the core metal.
The cored bar has a fixed cylindrical portion externally fitted and fixed to the outer peripheral surface of the axial end of the female shaft, and an inward flange portion bent radially inward from the axial end of the fixed cylindrical portion. Have.
The elastic member has a seal lip portion which brings the tip end edge into contact with the outer peripheral surface of the male shaft, and the outer peripheral surface (preferably the outer surface) of the core metal without covering the inner peripheral surface of the fixed cylindrical portion. Covering the whole).
Note that not covering the inner peripheral surface of the fixed cylindrical portion with the elastic material is not limited to a structure in which the entire inner peripheral surface of the fixed cylindrical portion is not covered with the elastic material at all, inevitably in terms of manufacture. A structure in which a part of the inner peripheral surface of the fixed cylindrical portion (for example, a portion which does not contact the outer peripheral surface of the female shaft when mounting the seal ring and does not contribute to the support rigidity of the seal ring) is covered by the elastic material including.

In the present invention, the fixed cylindrical portion may be provided with a locking piece protruding radially inward.
In this case, the elastic member can cover the cut formed in the periphery of the locking piece in the fixed cylindrical portion and opened in the outer peripheral surface of the fixed cylindrical portion from the outside.
Further, in the present invention, the inward facing flange portion can be bent at an acute angle with respect to the fixed cylindrical portion.

The telescopic shaft of the present invention is mounted on an axial end of a hollow cylindrical female shaft, a male shaft inserted inside the female shaft, and an axial end of the female shaft, and closes an axial end opening of the female shaft. It is equipped with a seal ring. The female shaft and the male shaft are combined such that torque can be transmitted and the entire length can be extended and contracted.
In particular, in the telescopic shaft of the present invention, the seal ring of the present invention is used as the seal ring.
In the telescopic shaft according to the present invention, the radially inward protruding locking piece provided on the fixed cylindrical portion is engaged with the radially inward recessed portion provided on the outer peripheral surface of the end of the female shaft. It can be done.
Furthermore, in the telescopic shaft of the present invention, the recess can be provided on the outer peripheral surface of a portion of the female shaft which is axially deviated from the range in which the male shaft slides in use.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that rust generate | occur | produces to a core metal, and the support rigidity with respect to an outer tube (female shaft) can be ensured.

FIG. 1 is a schematic partial cross-sectional view showing an example of a steering apparatus provided with an intermediate shaft according to a first example of the embodiment. FIG. 2 is a partial cross-sectional view showing an intermediate shaft and its peripheral member in the first example of the embodiment. FIG. 3 is an enlarged view of a portion A of FIG. FIG. 4 is a view corresponding to FIG. 3 and showing a second example of the embodiment. FIG. 5 is a view corresponding to FIG. 3 and showing a third example of the embodiment. FIG. 6 is a view corresponding to FIG. 3 showing an intermediate shaft of a conventional structure.

First Example of Embodiment
A first example of the embodiment will be described using FIGS. 1 to 3. In this example, the present invention is applied to an intermediate shaft that constitutes a steering apparatus for an automobile.

[Overview of steering device]
The steering apparatus for an automobile includes a steering wheel 12, a steering shaft 13, a steering column 14, a pair of universal joints 15a and 15b, an intermediate shaft 1a, a steering gear unit 16, and a pair of tie rods 17. Have.

  The steering shaft 13 is rotatably supported on the inside of a steering column 14 supported by the vehicle body. A steering wheel 12 operated by the driver is attached to a rear end portion of the steering shaft 13. A front end portion of the steering shaft 13 is a steering gear via a pair of universal joints 15a and 15b and an intermediate shaft 1a. It is connected to the pinion shaft 18 of the unit 16. Therefore, when the driver rotates the steering wheel 12, the rotation of the steering wheel 12 is transmitted to the pinion shaft 18 of the steering gear unit 16. The rotation of the pinion shaft 18 is converted to the linear motion of the rack engaged with the pinion shaft 18 to push and pull the pair of tie rods 17. As a result, a steering angle according to the operation amount of the steering wheel 12 is given to the steered wheels. The front-rear direction refers to the front-rear direction of the vehicle body on which the steering apparatus is mounted. In FIG. 1, the left side corresponds to the front side, and the right side corresponds to the rear side, while in FIGS. 2 and 3, the left side corresponds to the rear side and the right side corresponds to the front side.

[Intermediate shaft overview]
The intermediate shaft 1a of this example is used outside the vehicle, and has a hollow cylindrical outer tube 3a having a female spline portion 2a formed on the inner circumferential surface, and one axial end (a front end, as shown in FIG. The inner shaft 5a is provided with a male spline portion 4a formed on the outer peripheral surface of the right end portion 2). Then, the male spline portion 4a of the inner shaft 5a corresponding to the male shaft is inserted inside the outer tube 3a corresponding to the female shaft, and the male spline portion 4a and the female spline portion 2a are spline engaged. The outer tube 3a and the inner shaft 5a are combined such that torque can be transmitted and the entire length can be extended and contracted.

  Further, in this example, the outer tube 3a is disposed on the front side with respect to the longitudinal direction of the vehicle body, and the inner shaft 5a is disposed on the rear side with respect to the longitudinal direction of the vehicle body. Further, at one axial end of the outer tube 3a, a yoke 19 constituting a universal joint 15a disposed on the front side of the pair of universal joints 15a, 15b is externally fitted and fixed (press-fit). On the other hand, at the other axial end of the inner shaft 5a (left end in FIG. 2), the yoke 20 constituting the universal joint 15b disposed at the rear of the pair of universal joints 15a and 15b is externally fitted and fixed (Pressing in). In the case of practicing the present invention, the positional relationship between the outer tube 3a and the inner shaft 5a in the front-rear direction can be reversed to that in the present embodiment.

[Structure of seal ring]
In this example, a seal ring 6a is incorporated in the intermediate shaft 1a in order to prevent foreign matter such as rainwater and mud water from invading the spline engagement portion between the female spline portion 2a and the male spline portion 4a. Specifically, the seal ring 6a is attached to the other axial end of the outer tube 3a to close the other axial end opening of the outer tube 3a.

  The seal ring 6a includes a core 7a made of a metal plate and an elastic member 8a made of an elastic material such as rubber or elastomer fixed to the core 7a.

  Among them, the core metal 7a has a substantially J-shaped cross section and is formed in an annular shape as a whole, and a cylindrical fixed cylindrical portion 9a externally fitted and fixed to the outer peripheral surface of the other end in the axial direction of the outer tube 3a The inward facing flange portion 10a is bent radially inward and axially to one side from the other axial end portion of the fixed cylindrical portion 9a.

  The fixed cylindrical portion 9a is provided with locking pieces (crimped pieces) 21 protruding radially inward at a plurality of circumferentially equally spaced points. The locking piece 21 is formed by bending the inner side of a U-shaped cut 28 formed at the axially intermediate portion of the fixed cylindrical portion 9a at one side in the axial direction to the inner side in the radial direction. It is inclined toward the other side in the axial direction.

  In this example, in order to externally fit the fixed cylindrical portion 9a as described above, the small diameter portion 22 whose outer diameter is smaller than the portion adjacent to one side in the axial direction on the outer peripheral surface of the other end in the axial direction of the outer tube 3a. Form. In the illustrated example, the extent to which the small diameter portion 22 has an outer diameter smaller than the portion adjacent to one axial direction of the small diameter portion 22 is more than twice the thickness of the fixed cylindrical portion 9a (core metal 7a). It is slightly smaller.

  Further, in the axially middle portion of the small diameter portion 22, an annular recessed groove 23 having a rectangular shape in cross section, which is recessed inward in the radial direction, corresponding to the recessed portion is provided over the entire circumference. In this example, such an annular recessed groove 23 is axially aligned with the tapered portion 24 of the inner peripheral surface of the outer tube 3a in which the tooth tip surface of the spline teeth constituting the female spline portion 2a is tapered. It is provided in the portion (portion to overlap in the radial direction). That is, in the normal use state of the outer tube 3a, the annular recessed groove 23 is provided on the outer peripheral surface of the portion axially deviated from the range in which the male spline portion 4a of the inner shaft 5a slides. Thereby, the change in the shape of the inner peripheral surface of the outer tube 3a caused by the formation of the annular recessed groove 23 in the outer peripheral surface of the outer tube 3a is the expansion / contraction operation of the outer tube 3a and the inner shaft 5a (relative to the axial direction Not to affect the displacement). More specifically, the annular recessed groove 23 is formed to prevent an increase in the stroke load between the outer tube 3a and the inner shaft 5a.

  In this embodiment, the fixed cylindrical portion 9a is directly fitted to the small diameter portion 22 by press fitting without interposing any other member, and the other half of the locking piece 21 in the axial direction is placed inside the annular groove 23. I am getting into As a result, the other axial end edge (tip end edge) of the locking piece 21 is brought into contact with or close to the side surface of the annular groove 23. Further, a step formed by forming an axial end face (tip end face) of the fixed cylindrical portion 9a between the small diameter portion 22 and a portion adjacent to one axial direction side of the small diameter portion 22 in the outer peripheral surface of the outer tube 3a. The surface 25 is in contact with or close to the surface.

  The inward flange portion 10a is folded back by 90 degrees or more (about 150 degrees in the illustrated example) from the other axial end of the fixed cylindrical portion 9a. Therefore, the angle θ between the inward facing flange portion 10a and the fixed cylindrical portion 9a is an acute angle. Further, in this example, the bent portion (continuous portion) of the fixed cylindrical portion 9a and the inward facing flange portion 10a is curved in an arc shape in cross section. The inside diameter dimension of the inward facing flange portion 10a is smaller than the outside diameter dimension of the male spline portion 4a in the outer peripheral surface of the inner shaft 5a, and is outside the small diameter cylindrical surface portion 26 axially away from the male spline portion 4a. Larger than diameter size. Further, the radially inner end portion of the inward facing flange portion 10a is located on one side in the axial direction of the other end surface in the axial direction of the outer tube 3a, and enters the inner diameter side of the outer tube 3a.

  The elastic member 8a is fixed to the surface of the above-mentioned core metal 7a by vulcanization adhesion, and includes a seal lip portion 11a and a cover portion 27. Among these, the cover portion 27 covers most of the outer surface which is the surface facing the outer space side in the state of being attached to the outer tube 3a among the surfaces of the cored bar 7a. Specifically, the cover portion 27 covers the outer peripheral surface of the fixed cylindrical portion 9a and the other side surface in the axial direction of the inward flange portion 10a over the entire circumference. For this reason, the covering portion 27 is formed around the locking piece 21 in the fixed cylindrical portion 9a and covers the U-shaped cut 28 opened in the outer peripheral surface of the fixed cylindrical portion 9a from the outside ( The gap by the cut 28 is closed). In addition, in the present embodiment, the cover portion 27 also covers the inner peripheral edge portion of the inward flange portion 10a and the axial one side surface of the radially inner end portion of the inward flange portion 10a. On the contrary, in the core metal 7a, the inner peripheral surface of the fixed cylindrical portion 9a and the axial direction one side surface of the inward flange portion 10a other than the end portion on the inner diameter side are not covered by the cover 27 and the core metal 7a Is exposed. Further, in the illustrated example, one axial end face (tip face) of the fixed cylindrical portion 9a abuts or approaches the stepped surface 25 of the outer tube 3a, and most of the end face is not exposed to the external space Therefore, it is not covered by the cover part 27. However, in order to prevent rain water or muddy water from entering the gap between the inner peripheral surface of the fixed cylindrical portion 9a and the small diameter portion 22, the axial direction end face of the fixed cylindrical portion 9a is also covered by the covering portion 27 By covering, the entire outer surface of the core 7 a may be covered by the covering portion 27. Further, the thickness dimension of the cover portion 27 is sufficient if it can exhibit the function of covering the outer surface of the metal core 7a, and can be thinner than the illustrated structure. Further, the thickness dimension of the cover portion 27 may be the same as or different from each other in the portion covering the fixed cylindrical portion 9a and the portion covering the inward flange portion 10a.

  The seal lip portion 11a is substantially triangular in cross section, and its base end portion is fixed to a radially intermediate portion on the other axial side surface of the inward flange portion 10a. Further, the seal lip portion 11a is inclined in the direction toward the other side in the axial direction as it goes radially inward (from the base end portion to the tip end portion), and the tip end edge thereof is one of the outer peripheral surfaces of the inner shaft 5a. The small diameter cylindrical surface portion 26 is in contact in a state where an interference is given.

  The intermediate shaft 1a of the present embodiment as described above is intermediately displaced by axially displacing the outer tube 3a and the inner shaft 5a when vibration is input from the wheels during traveling or when assembling to the vehicle body. The shaft 1a can be expanded and contracted. In addition, when the intermediate shaft 1a is extended and contracted, the seal ring 6a attached to the other end of the outer tube 3a in the axial direction is in sliding contact with the small diameter cylindrical surface 26 of the inner shaft 5 at the tip edge of the seal lip 11a. By doing this, the axial direction other end opening of the outer tube 3a is closed. Thereby, by using the intermediate shaft 1a outside the vehicle, even when foreign matter such as rain water or muddy water adheres to the intermediate shaft 1a, such foreign matter is a spline engagement between the female spline portion 2a and the male spline portion 4a. It can be effectively prevented from invading the joint.

  Particularly in this example, the outer peripheral surface of the fixed cylindrical portion 9a and the other axial side surface of the inward facing flange portion 10a, which are the outer surfaces of the core metal 7a constituting the seal ring 6a, are all covered by the cover portion 27 constituting the elastic member 8a. Covering around the circumference. Therefore, even when foreign matter adheres to the seal ring 6a, the occurrence of rusting on the cored bar 7a can be effectively prevented. Therefore, it is possible to effectively prevent the progress of rusting on the outer tube 3a to which the cored bar 7a is fitted and fixed. Further, the covering portion 27 covering the outer peripheral surface of the fixed cylindrical portion 9a can effectively prevent foreign matter such as rain water and mud water from invading through the U-shaped cut 28.

  Moreover, in the present embodiment, the inner peripheral surface of the fixed cylindrical portion 9a constituting the core metal 7a is not covered by the covering portion 27, and the inner peripheral surface of the fixed cylindrical portion 9a is the small diameter portion 22 of the outer tube 3a. On the other hand, they are directly press-fitted without any other member. Therefore, sufficient support rigidity of the seal ring 6a with respect to the outer tube 3a can be secured. Therefore, the contact state between the seal lip portion 11a and the small diameter cylindrical surface portion 26 of the inner shaft 5a can be stabilized.

  Further, the locking piece 21 provided on the fixed cylindrical portion 9a is made to enter the inside of the annular groove 23 provided on the outer peripheral surface of the outer tube 3a, and the other end edge (tip edge) of the locking piece 21 in the axial direction Since the side surface of the annular groove 23 is in contact with or close to the side surface, it is possible to effectively prevent the seal ring 6a from coming off the outer tube 3a to the other side in the axial direction.

  Furthermore, since the inner diameter dimension of the inward facing flange portion 10b is set larger than the outer diameter dimension of the small diameter cylindrical surface portion 26 of the inner shaft 5a, the inner shaft 5a is smooth inside the outer tube 3a in a normal use state Can be displaced (sliding).

  On the other hand, when a large force directed to the other side in the axial direction, which is the direction of coming out of the inner side of the outer tube 3a, acts on the inner shaft 5a during assembly work of the intermediate shaft 1a, etc. Since it is smaller than the outer diameter size of the spline portion 4a, the radially inner end portion of the inward flange portion 10a abuts on the male spline portion 4a. Then, a force directed to the other side in the axial direction is applied to the inward flange portion 10a. Here, since the inward flange portion 10a of this example is folded back by 90 degrees or more from the other axial end of the fixed cylindrical portion 9a, the included angle θ between the fixed cylindrical portion 9a and the inward flange portion 10a is large. As a result, bending deformation of the inward flange portion 10a proceeds. Then, the inside diameter of the inward facing flange portion 10 a gradually decreases and becomes equal to the outside diameter of the small diameter cylindrical surface portion 26.

  When the inner diameter dimension of the inward facing flange portion 10a becomes equal to the outer diameter dimension of the small diameter cylindrical surface portion 26, the radially inner end edge of the inward facing flange portion 10a contacts the outer peripheral surface of the small diameter cylindrical surface portion 26 (sticks). Bending deformation stops. Then, even when a force directed from the inner shaft 5a to the other side in the axial direction acts on the inward facing flange portion 10a more than that, only compressive force acts on the inward facing flange portion 10a, and bending deformation does not occur. As a result, it is possible to effectively prevent the inner shaft 5a from coming off to the other side in the axial direction from the inside of the outer tube 3a. As described above, in the present embodiment, the seal ring 6a can exhibit the function of preventing the inner shaft 5a from coming off the outer tube 3a. In this example, since the locking piece 21 provided on the fixed cylindrical portion 9a is made to enter the inside of the annular groove 23 provided on the outer peripheral surface of the outer tube 3a, the inner shaft 5a to the inward flange portion 10a. Even when a force directed to the other side in the axial direction acts, the seal ring 6a does not come out of the outer tube 3a to the other side in the axial direction.

Second Example of Embodiment
A second example of the embodiment will be described with reference to FIG. In the present example, the shape of the metal core 7b constituting the seal ring 6b is different from the structure of the first example of the embodiment. That is, the inward flange portion 10b constituting the metal core 7b is provided so as to be bent at a right angle inward in the radial direction from the other axial end portion of the fixed cylindrical portion 9a. That is, the inward flange portion 10b is turned 90 degrees from the other axial end of the fixed cylindrical portion 9a. Therefore, the radially inner end portion of the inward flange portion 10b is located on the other axial side with respect to the other axial end surface of the outer tube 3a, and does not enter the inner diameter side of the outer tube 3a.

  However, also in this example, the cover portion 27 constituting the elastic member 8a covers the outer peripheral surface of the fixed cylindrical portion 9a and the other side surface in the axial direction of the inward flange portion 10b, which are the outer surfaces of the core 7b. . Furthermore, in the present embodiment, the cover portion 27 also covers the axial peripheral one side surface of the inner peripheral edge portion of the inward flange portion 10b and the radially inner end portion of the inward flange portion 10b. On the other hand, in the core metal 7b, the inner peripheral surface of the fixed cylindrical portion 9a and the axially inner surface of the inward flange portion 10b are not covered by the covering portion 27 except the end portion on the inner diameter side. 7b is exposed.

  Also in the above example, most of the surface exposed to the outside of the seal ring 6b is made of the elastic member 8a, and the cored bar 7b is removed except for one axial end face of the fixed cylindrical portion 9a. Not exposed to the outside. Therefore, even when foreign matter adheres to the seal ring 6b, the occurrence of rusting on the cored bar 7b can be effectively prevented. Other configurations and operational effects are the same as the first example of the embodiment.

Third Example of Embodiment
A third example of the embodiment will be described with reference to FIG. In this example, the shape of the cored bar 7c constituting the seal ring 6c is different from any of the structures of the first example of the embodiment and the second example of the embodiment. That is, the fixed cylindrical portion 9b constituting the cored bar 7c is formed in a simple cylindrical shape, and the locking piece projecting inward in the radial direction is not provided. Further, as in the second example of the embodiment, the inward flange portion 10b is provided so as to bend radially inward at a right angle from the other axial end portion of the fixed cylindrical portion 9b.

  However, also in this example, the cover portion 27 constituting the elastic member 8a covers the outer peripheral surface of the fixed cylindrical portion 9b and the other side surface in the axial direction of the inward flange portion 10b, which are the outer surfaces of the core 7c. . Furthermore, in the present embodiment, the cover portion 27 also covers the axial peripheral one side surface of the inner peripheral edge portion of the inward flange portion 10b and the radially inner end portion of the inward flange portion 10b. On the contrary, in the metal core 7c, the inner peripheral surface of the fixed cylindrical portion 9b and the axial direction one side surface of the inward facing flange portion 10b are not covered by the cover 27 but the core metal 7c. 7c is exposed.

  Also in the above example, most of the surface exposed to the outside of the seal ring 6c is made of the elastic member 8a, and the cored bar 7c is removed except for one axial end face of the fixed cylindrical portion 9b. Not exposed to the outside. Therefore, even when foreign matter adheres to the seal ring 6c, the occurrence of rusting on the cored bar 7c can be effectively prevented. Moreover, in this example, it is not necessary to provide the annular groove for engaging a locking piece in the outer peripheral surface of the outer tube 3b. Other configurations and operational effects are the same as the first example of the embodiment.

  As a telescopic shaft incorporating the seal ring of the present invention, a male shaft having a female spline portion formed on the inner peripheral surface and a male spline portion formed on the outer peripheral surface as in the structures of the respective embodiments. The structure is not limited to the structure in which torque transmission and expansion and contraction are combined with the shaft in a state where the female spline portion and the male spline portion are in spline engagement. For example, as described in WO 2003/031250, an intermediate member such as a ball or a roller is disposed between the inner peripheral surface of the female shaft and the outer peripheral surface of the male shaft, and these female shaft and male A structure in which the shaft is combined with the shaft so as to be capable of torque transmission and expansion and contraction is also considered. In addition, the telescopic shaft incorporating the seal ring of the present invention is not limited to a structure that can be expanded and contracted in a normal use state, and a structure that can expand and contract when an excessive force acts at the time of secondary collision etc. .

DESCRIPTION OF SYMBOLS 1, 1a Intermediate shaft 2, 2a Female spline part 3, 3a, 3b Outer tube 4, 4a Male spline part 5, 5a Inner shaft 6, 6a, 6b, 6c Seal ring 7, 7a, 7b, 7c Core metal 8, 8a Elastic members 9, 9a, 9b Fixed cylinder 10, 10a, 10b Inward facing flange 11, 11a Seal lip 12 Steering wheel 13 Steering shaft 14 Steering column 14 Steering column 15a, 15b Universal joint 16 Steering gear unit 17 Tie rod 18 Pinion shaft 19 Yoke 20 Yoke 21 locking piece 22 small diameter portion 23 annular recessed groove 24 tapered portion 25 step surface 26 small diameter cylindrical surface portion 27 cover portion 28 cut

Claims (7)

A seal ring incorporated in a telescopic shaft comprising a hollow cylindrical female shaft and a male shaft that is capable of transmitting torque and capable of extending and contracting its entire length,
A metal cored bar and an elastic material fixed to the cored bar;
The cored bar has a fixed cylindrical portion externally fitted and fixed to the outer peripheral surface of the axial end of the female shaft, and an inward flange portion bent radially inward from the axial end of the fixed cylindrical portion. Have,
The elastic member has a seal lip portion that brings the tip end edge into contact with the outer peripheral surface of the male shaft, and covers the outer surface of the core without covering the inner peripheral surface of the fixed cylindrical portion.
Seal ring.   The seal ring according to claim 1, wherein the fixed cylindrical portion is provided with a locking piece that protrudes radially inward.   The seal according to claim 2, wherein the elastic material is formed around the locking piece in the fixed cylindrical portion, and covers the incision opened on the outer peripheral surface of the fixed cylindrical portion from the outside. ring.   The seal ring according to any one of claims 1 to 3, wherein an angle between the inward facing flange portion and the fixed cylindrical portion is an acute angle. A hollow cylindrical female shaft, a male shaft inserted inside the female shaft, and a seal ring mounted on an axial end of the female shaft and closing an opening in the axial direction of the female shaft; A telescopic shaft combining a female shaft and the male shaft so as to be able to transmit torque and extend and contract its entire length,
An expandable shaft, wherein the seal ring is the seal ring according to any one of claims 1 to 4.   The fixed cylindrical portion is provided with a locking piece that protrudes radially inward, and the locking piece is recessed radially inward provided on the outer peripheral surface of the end of the female shaft The telescopic shaft according to claim 5, engaged in the recess.   The telescopic shaft according to claim 6, wherein the recessed portion is provided on an outer peripheral surface of a portion of the female shaft which is axially deviated from a range in which the male shaft slides in use.

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