JP4833946B2 - Anti-vibration bush - Google Patents

Description

The present invention
An inner cylinder, an outer cylinder, and a rubber-like elastic body connecting the inner cylinder and the outer cylinder;
The present invention relates to an anti-vibration bushing in which the axial center of the inner cylinder is displaced in the axial direction of the inner and outer cylinders with respect to the axial center of the outer cylinder.

Conventionally, this type of anti-vibration bushing is press-fitted into a press-fitting hole such as a suspension arm of an automobile, and is fixed to a member on the vehicle body side with a fixing bolt inserted through an inner cylinder. FIG. 9 is a longitudinal sectional view of a conventional vibration isolating bush 1.
The anti-vibration bush 1 includes an inner cylinder 3 that is sandwiched between a pair of clamping members of the vehicle side bracket, and an outer cylinder 4 that is disposed around the inner cylinder 3 and is press-fitted into a press-fitting hole (not shown) of a suspension arm. The rubber-like elastic body 5 interposed between the inner and outer cylinders 3 and 4 and vulcanized and bonded to the inner and outer cylinders 3 and 4 is provided.

  The vibration isolating bush 1 is fitted and fixed to the suspension arm. The axial direction of the inner cylinder 3 depends on the direction in which the vibration isolating bush 1 suppresses vibration and the structural relationship around the press-fitting hole of the suspension arm. Is shifted in the axial direction J of the inner and outer cylinders 3 and 4 with respect to the axial center Q of the outer cylinder 4. d is the amount of displacement.

  In this structure, for example, the difference in the axial direction J between the one end surface 19A in the axial direction J of the inner cylinder 3 and the corresponding one end surface 16A in the axial direction J of the outer cylinder 4 is the axial direction of the inner cylinder 3. When the difference in the axial direction J between the other end surface 19B of J and the other end surface 16B in the axial direction J of the outer cylinder 4 corresponding thereto is larger, the vibration isolating bush on the one end surfaces 19A, 16A side of the inner and outer cylinders 3, 4 The assembly direction which is the press-fit direction is in one direction, such that one end portion of 1 is always on the top and the one end portion of the vibration isolating bush 1 on the other end surfaces 19B and 16B side of the inner and outer cylinders 3 and 4 is on the bottom. It is determined.

Therefore, when the vibration isolating bush 1 is press-fitted into the vertical press-fitting hole with the axis O along the vertical direction, the press-fitting direction (assembly direction) of the vibration isolating bush in the vertical direction should not be mistaken. It is necessary to press fit.
Similarly, when the anti-vibration bush is press-fitted into the horizontal press-fitting hole with the shaft core along the left-right direction, it is necessary to press-fit so that the press-fitting direction of the anti-vibration bush in the left-right direction is not mistaken. The same applies to the front-rear direction or the diagonal left-right direction.
Therefore, conventionally, in order to allow the operator to grasp the press-fitting direction, the end face in the axial direction of the vibration isolating bush is marked with a paint.

According to the above-mentioned conventional means, the end face in the axial direction of the vibration isolating bush is marked with paint as means for allowing the operator to identify the assembly direction (press-fit direction) to the assembly object of the vibration isolating bush. In addition, the application work of the paint to the anti-vibration bush is necessary, and there are problems that the number of processes is increased and the work is costly.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vibration isolating bush that can identify the assembly direction easily and at low cost.

The structure, operation, and effect of the invention of claim 1 are as follows.
[Constitution]
An inner cylinder, an outer cylinder, and a rubber-like elastic body connecting the inner cylinder and the outer cylinder;
A vibration-proof bushing in which the axial center of the inner cylinder is displaced in the axial direction of the inner and outer cylinders with respect to the axial center of the outer cylinder,
On one end surface and other end surface in the axial direction of the rubber-like elastic body, the inner cylinder identification protrusion is the rubber-like for identifying the center of the axial direction and the direction of the positional deviation between the axial direction of the center of the outer cylinder of the It is vulcanized and molded integrally with an elastic body, and the identification protrusion is disposed on the axially inner side of the axial end surface of the outer cylinder,
A plurality of identification protrusions on one end face side are provided at equal angles around the axis of the inner cylinder, and the identification protrusions on the other end face side are provided in different shapes from the identification protrusions on the one end face side. ,
A stopper sheet as an impact absorbing member for avoiding the axial end of the outer cylinder from colliding with another object is externally fitted to one end of the inner cylinder in the axial direction. Affixed to the end face in the axial direction .

[Action / Effect]
On the end face in the axial direction of the rubber-like elastic body, an identification protrusion for identifying the direction of displacement between the axial center of the inner cylinder and the axial center of the outer cylinder is integrally vulcanized with the rubber-like elastic body. Therefore, the operator can grasp the direction of the displacement at a glance by the identification protrusion, and can assemble the vibration isolating bush to the assembling object in the correct assembling direction.
Furthermore, since the identification protrusion is vulcanized and molded integrally with the rubber-like elastic body, the work process (paint coating process) can be omitted compared to the method of applying the identification mark to the vibration-proof bushing after vulcanization molding. This can reduce the manufacturing cost.
In addition, by making the identification shape of the identification protrusion a protrusion rather than a recess, it is possible to avoid a decrease in the amount of the rubber-like elastic body, and to make it difficult to adversely affect the vibration-proof characteristics of the rubber-like elastic body.

Further, since a plurality of identification protrusions on the one end face side are provided at equal angles around the axis of the inner cylinder, the identification protrusions are regularly arranged in appearance. Therefore, when the operator sees the identification protrusion, it can be understood that the object is made for some purpose, and the operator can be prevented from erroneously recognizing that the defective protrusion is on the rubber-like elastic body.

Further, by changing the shape of the identification protrusion provided on one end face in the axial direction of the rubber-like elastic body and the identification protrusion provided on the other end face, the assembly direction of the vibration isolating bush can be changed to one end face or the other. It can be identified simply by looking at the end face. As an example, when the anti-vibration bush is press-fitted in the vertical press-fitting hole in the vertical direction, the difference in the axial direction between the one end surface in the axial direction of the inner cylinder and the corresponding one end surface in the axial direction of the outer cylinder is If the difference in the axial direction between the other axial end of the cylinder and the other axial end of the corresponding outer cylinder is greater than the axial end of the cylinder, the one end face of the rubber-like elastic body located on the one end face side of the inner and outer cylinders By setting the identification protrusion on the upper side and the identification protrusion on the other end surface of the rubber-like elastic body located on the other end surface side of the inner and outer cylinders in the lower direction, the operator can quickly and easily install the vibration isolating bush. Can be identified.
Moreover, the following effect | action and effect can be show | played by arrange | positioning the said identification protrusion in the axial direction inner side rather than the end surface of the axial direction of the said outer cylinder. That is, when the stopper sheet as an impact absorbing member for avoiding the end of the outer cylinder colliding with another object is externally fitted to the end of the inner cylinder and attached to the end surface of the outer cylinder, according to the above configuration Since the identification protrusion is arranged on the inner side in the axial direction from the axial end surface of the outer cylinder, it is possible to avoid the identification protrusion from interfering with the stopper sheet. Further, it is possible to suppress the volume of the identification protrusion from becoming too large, and it is possible to make it difficult to adversely affect the vibration isolation characteristics.

The structure, operation and effect of the invention of claim 2 are as follows.
[Constitution]
In the configuration according to the invention of claim 1,
The identification protrusion is formed in a ring shape concentric with the inner cylinder.

[Action / Effect]
In addition to the operations and effects of the configuration of the first aspect, the following operations and effects can be achieved.
Since the identification protrusion is provided in a ring shape concentric with the inner cylinder, there is little discomfort in appearance, and the influence of the identification protrusion on the rubber-like elastic body can be made the same around the axis of the inner cylinder. Therefore, it is possible to make it difficult to adversely affect the characteristics of the rubber-like elastic body.
Also, when manufacturing a mold that forms a rubber-like elastic body, it is only necessary to form a ring-shaped recess as a cavity for the identification protrusion on the mold, so that the identification protrusion is locally formed on the rubber-like elastic body. This makes it easier to manufacture the mold than in the case of doing so.

The configuration, operation, and effect of the invention of claim 3 are as follows.
[Constitution]
In the configuration according to the invention of claim 1 or 2 ,
A connecting portion between the identification protrusion and the rubber-like elastic body portion around the identification protrusion is formed on a curved surface.

[Action / Effect]
In addition to the claim 1 or 2 of the above-described operation and effects of the constitution can achieve the following effects.
Since the connecting portion between the identification protrusion and the rubber-like elastic body portion around the identification protrusion is formed in a curved surface, it is possible to avoid the concentration of force on the connection portion and to improve the durability of the rubber-like elastic body. Not only can this be improved, but also during the vulcanization molding of the rubber-like elastic body, the flow of the rubber compound in the cavity portion corresponding to the identification protrusion can be improved, and gas accumulation can be eliminated. As a result, it is possible to avoid the loss of the rubber-like elastic body while having a structure in which the identification protrusion is formed on the rubber-like elastic body.

  ADVANTAGE OF THE INVENTION According to this invention, the anti-vibration bush which can identify an assembly | attachment direction at low cost easily was able to be provided.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
[First Embodiment : Reference Example ]
The anti-vibration bush 1 is shown in FIGS.
The anti-vibration bush 1 includes an inner cylinder 3 that is clamped and fixed to a pair of clamping members 22 of the vehicle-side bracket 2 via mounting bolts 9 and nuts 10, and an outer fitting press-fit hole H of the suspension arm A. A cylinder 4 and a rubber-like elastic body 5 interposed between the inner and outer cylinders 3 and 4 and bonded by vulcanization are provided.

  As shown in FIG. 4, a rubber stopper sheet 6 is fitted on one end of the inner cylinder 3 in the axial direction. This stopper sheet 6 avoids a direct collision between one clamping member 22 of the pair of clamping members 22 and the one end surface 16A of the outer cylinder 4 to absorb the impact force, and abnormal noise and vibration are generated. It plays a role in suppressing the occurrence.

  The inner cylinder 3 is a thick-walled cylindrical pipe, and a rubber-like elastic body 3 is vulcanized and formed at an intermediate portion in the axial direction except for both ends thereof. The hollow hole of the inner cylinder 3 is a bolt insertion hole 8 through which the mounting bolt 9 is inserted.

  The outer cylinder 4 is a thin-walled cylindrical pipe. The outer cylinder 4 has a fixed portion 11 of the rubber-like elastic body 5 in most of the inner peripheral portion except for a small area at both ends (see FIG. 2). The rubber-like elastic body 5 is formed in an arc shape that is recessed in the axial direction center side of the rubber-like elastic body 5 in the longitudinal section.

As shown in FIG. 2, the anti-vibration bush 1 has the center P in the axial direction J of the inner cylinder 3 and the center Q in the axial direction of the outer cylinder 4 not aligned in the axial direction J of the inner and outer cylinders 3 and 4. Both centers P and Q are displaced in the axial direction J of the inner and outer cylinders 3 and 4.
And the assembly direction of the vibration isolating bush 1 to the press-fitting hole H is determined in one direction by the positional deviation amount d.

  That is, in the present embodiment, the difference in the axial direction J between the one end surface 19A in the axial direction of the inner cylinder 3 and the corresponding one end surface 16A in the axial direction J of the outer cylinder 4 is the axial direction of the inner cylinder 3. Since the difference in the axial direction between the other end face 19B of J and the other end face 16B in the axial direction J of the outer cylinder 4 corresponding thereto is larger, the vibration isolating bush 1 on the one end face sides 19A, 16A of the inner and outer cylinders 3, 4 Assembling direction is determined to be one direction so that one end portion of the anti-vibration bush 1 is necessarily on the upper side and one end portion of the anti-vibration bush 1 on the other end surfaces 19B, 16B side of the inner and outer cylinders 3, 4 is on the lower side.

  Since it is configured in this manner, the rubber-like elastic body of the vibration-isolating bushing 1 is provided so that the operator can easily identify the assembly direction for the purpose of preventing the worker from assembling upside down. 5 is provided with an identification protrusion 13 on one end face 12A.

  As shown in FIG. 1, a plurality of identification protrusions 13 are provided around the axis O of the inner cylinder 3 at equal angles. That is, four pieces are formed around the axis at every 90 ° angle. Instead of this structure, for example, three may be provided for each angle of 120 °.

As described above, since a plurality of identification protrusions 13 are provided around the axis O of the inner cylinder 3 at equal angles, the identification protrusions 13 are regularly arranged in appearance.
Therefore, when the operator looks at the identification protrusion 13, it can be seen that it is made for some purpose, and the operator does not mistakenly recognize that a defective protrusion is present on the rubber-like elastic body 5. it can.

As shown in FIG. 3, the identification protrusion 13 is formed on one end surface portion of the end surface 12 </ b> A of the rubber-like elastic body 5, which has a gentle vertical cross-section near the inner cylinder 3 side.
Then, as viewed from the axial direction J of the inner and outer cylinders 3 and 4, the identification protrusion 13 is formed in a rectangular shape, and the corner portion (corner portion) is formed in an arc shape (specifically, an arc shape having a radius of 1 mm). It is.

  Further, as shown in FIG. 3, the first surface M1 of the identification protrusion 13 facing the outer cylinder 4 side is formed along the axial direction J of the inner and outer cylinders 3 and 4, and the outer sides of the inner and outer cylinders 3 and 4 are axially outward. A second surface M2 facing the side (opposite to the axial center of the rubber-like elastic body 5) is formed so as to be along a direction (axial perpendicular direction) perpendicular to the axial direction J.

Further, a corner portion (corner portion) between the first surface M1 and the second surface M2 is formed in an arc shape (specifically, an arc shape having a radius of 1 mm), a root of the first surface M1, and a rubber shape A connecting portion N1 with the arc-shaped one end surface 12A of the elastic body 5 is formed in an arc shape (specifically, an arc shape with a radius of 1 mm), and the base of the second surface M2 and the arc-shaped shape of the rubber-like elastic body 5 are formed. The connecting portion N2 with the one end surface 12A is formed in an arc shape (specifically, an arc shape having a radius of 1 mm).
Thereby, in each corner part etc., it can make it easy to escape air at the time of vulcanization molding, and it can make it easy to avoid the loss of rubber-like elastic body 5. Further, it is possible to avoid the concentration of force around the identification protrusion 13 of the rubber-like elastic body 5 and to improve the durability of the rubber-like elastic body 5.

  As shown in FIG. 3, the first surface M <b> 1 of the identification protrusion 13 is arranged closer to the axial center side of the rubber-like elastic body 5 than the one end surface 16 </ b> A of the outer cylinder 4. Thereby, interference with the end surface of the stopper sheet 6 is avoided. That is, the identification protrusion 13 is arranged on the inner side J1 in the axial direction from the one end face 16A in the axial direction J of the outer cylinder 4.

  The rubber-like elastic body 5 is a cylindrical member interposed between the inner and outer cylinders 3 and 4 and is vulcanized and bonded to the inner and outer cylinders 3 and 4. As the material of the rubber-like elastic body 5, natural rubber or synthetic rubber generally used for vibration-proof rubber, for example, styrene butadiene rubber, butadiene rubber, isoprene rubber, acrylonitrile butadiene rubber, chloroprene rubber, butyl rubber, Ethylene propylene rubber or urethane elastomer is used. These raw rubbers contain compounding agents such as vulcanizing agents, vulcanization accelerators, anti-aging agents, reinforcing agents, fillers, softeners, etc., and predetermined elastic modulus, mechanical strength, dynamic characteristics, fatigue characteristics, etc. To get.

As shown in FIG. 2, the rubber-like elastic body 5 of the present embodiment is formed such that the length of the fixing portion 7 with respect to the inner cylinder 3 is larger than the length of the fixing portion 11 with respect to the outer cylinder 4.
For this reason, the shape of the rubber-like elastic body 5 is a trapezoidal shape in which the inclined surface has the above-mentioned gentle vertical cross-section arc shape in the cross section in the axial direction J, and moreover from both end faces 16A, 16B of the outer cylinder 4 in the axial direction J. Also, the portion 18 of the rubber-like elastic body 5 fixed to the inner cylinder 3 protrudes.
With this shape, the outer cylinder 4 can be stably supported by the inner cylinder 3.

As shown in FIG. 4, the stopper sheet 6 is configured to be thin and formed in a ring shape that is separate from the anti-vibration bush 1. A portion 6 </ b> A on the inner peripheral side of the stopper sheet 6 is elastically deformed and covers a portion on the inner cylinder 3 side of the rubber-like elastic body 5.
Further, the end surface on the outer peripheral side of the stopper sheet 6 is bonded to one end surface 16A of the outer cylinder 4 with an adhesive. Thus, the stopper sheet 6 is integrated with the vibration isolating bush 1.

  As described above, since the identification protrusion is disposed on the inner side J1 in the axial direction from the one end face 16A in the axial direction J of the outer cylinder 4, the identification protrusion 13 is prevented from interfering with the stopper sheet 6. be able to.

  According to the above structure, the direction of displacement between the center P in the axial direction J of the inner cylinder 3 and the center Q in the axial direction J of the outer cylinder 4 is identified on one end face 12A in the axial direction J of the rubber-like elastic body 5. Since the identification protrusion 13 for vulcanization is integrally formed with the rubber-like elastic body 5, the operator can grasp the direction of the displacement at a glance by the identification protrusion 13, so that the vibration isolating bush 1 is correct. It can be press-fitted into the press-fitting hole H of the arm A in the assembling direction.

In addition, by making the identification shape of the identification protrusion 13 not a concave portion but a protrusion, it is possible to avoid a decrease in the amount of the rubber-like elastic body 5 and make it difficult to adversely affect the vibration isolation characteristics of the rubber-like elastic body 5. it can.
Furthermore, since the identification protrusion 13 is vulcanized and molded integrally with the rubber-like elastic body 5, the work process (paint coating process) is compared with the method of applying the identification mark to the vibration isolating bush 1 after vulcanization molding. This can save the manufacturing cost.

[Second Embodiment : Reference Example ]
5 and 6 show a second embodiment.
In the second embodiment, the identification protrusion 33 is formed in a ring shape concentric with the inner cylinder 3.
The operator can identify the direction of positional deviation between the center P of the inner cylinder 3 in the axial direction J and the center Q of the outer cylinder 4 in the axial direction J by the presence of the ring-shaped identification protrusion 33. The ring-shaped identification protrusion 33 is also located on the inner side J1 in the axial direction from the one end face 16A in the axial direction J of the outer cylinder 4.

According to the configuration of the second embodiment, when a mold for forming the rubber-like elastic body 5 is manufactured, a ring-shaped recess as a cavity portion for the identification protrusion may be formed in the mold. Compared with the case where the identification protrusion is locally formed on the elastic body 5, the mold can be easily manufactured.
Further, since the identification protrusion 33 is provided in a ring shape concentric with the inner cylinder 3, there is little discomfort in appearance, and the influence of the identification protrusion 33 on the rubber-like elastic body 5 is influenced around the axis O of the inner cylinder 3. Can be the same. Accordingly, it is possible to make it difficult to adversely affect the characteristics of the rubber-like elastic body 5.

[Third Embodiment]
FIG. 7 shows a third embodiment.
In the third embodiment, identification protrusions 13 and 33 are provided on one end face 12A and the other end face 12B in the axial direction J of the rubber-like elastic body 5, and the identification protrusion 13 on the one end face 12A side and the other end face 12B side are provided. The shape of the identification protrusion 33 is different.
That is, the identification protrusions 13 formed at the aforementioned 90 ° angles are provided on one end face 12A in the axial direction J of the rubber-like elastic body 5, and the ring-like identification is provided on the other end face 12B of the rubber-like elastic body 5. A protrusion 33 is provided.

According to this structure,
By changing the shape of the identification protrusion 13 provided on the one end face 12A in the axial direction J of the rubber-like elastic body 5 and the identification protrusion 33 provided on the other end face 12B, the assembly direction of the vibration isolating bush 1 is They can be identified by simply looking at one end surface 12A or the other end surface 12B.

  That is, as shown in FIG. 8, the difference in the axial direction J between the one end surface 19 </ b> A in the axial direction J of the inner cylinder 3 and the corresponding one end surface 16 </ b> A in the axial direction J of the outer cylinder 4 is In the case of the above structure, which is larger than the difference in the axial direction J between the other end surface 19B in the axial direction J and the other end surface 16B in the axial direction J of the outer cylinder 4 corresponding thereto, the one end surfaces 19A, 16A of the inner and outer cylinders 3, 4 The identification protrusion 13 on the one end face 12A of the rubber-like elastic body 5 located on the side is the upper side, and the identification protrusion 33 on the other end face 12B of the rubber-like elastic body 5 located on the other end faces 19B, 16B side of the inner and outer cylinders 3, 4 is used. By setting the bottom, the operator can quickly and easily identify the assembly direction of the vibration isolating bush 1.

The present invention is not limited to the configuration of the above embodiment, and various modifications can be made within the scope of the gist of the present invention.
(1) Since the identification protrusions 13 and 33 are protrusions for allowing an operator to identify a specific direction of the vibration isolating bush 1, various forms can be adopted in addition to the embodiment.
For example, you may form in the protrusion extended in the radial direction toward the outer cylinder 4 from the inner cylinder 3. FIG. Moreover, you may form the projection group of a predetermined pattern in end surface 12A, 12B of a rubber-like elastic body.

(3) In the above embodiment, the anti-vibration bush that is press-fitted into the press-fitting hole H of the suspension arm has been described as an example. For example, the anti-vibration bush that is press-fitted into the press-fitting hole of the arm interposed between the engine and the vehicle body. The present invention can also be applied to a vibration bush.

(4) The anti-vibration bush 1 is not limited to the vertical direction, and may be press-fitted in various directions (left-right direction / front-rear direction, diagonal up-down direction, etc.). The present invention is not limited to the embodiment, and the present invention can also be applied to the vibration isolating bush 1 that is press-fitted in the various directions.

Front view of anti-vibration bush AA line longitudinal sectional view of the vibration isolating bush of FIG. Fig. 3 is an enlarged cross-sectional view of the anti-vibration bush near the identification protrusion Longitudinal sectional view showing an example of usage of vibration-proof bushing Longitudinal sectional view of the vibration isolating bush of the second embodiment Front view of anti-vibration bushing of second embodiment Longitudinal sectional view of the vibration isolating bush of the third embodiment The longitudinal cross-sectional view which shows an example of the use condition of the vibration isolating bush of 3rd Embodiment Longitudinal section of a conventional anti-vibration bush

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Anti-vibration bush 2 Vehicle side bracket 3 Inner cylinder 4 Outer cylinder 5 Rubber-like elastic body 6 Stopper sheet 6A Inner peripheral part 7 of stopper sheet Inner cylinder adhering part 8 Insertion hole 9 Bolt 10 Nut 11 Adherence of outer cylinder Part 12A One end face of rubber-like elastic body (end face in the axial direction of rubber-like elastic body)
12B The other end face of the rubber-like elastic body (the end face in the axial direction of the rubber-like elastic body)
13 Identification protrusion 16A One end surface of the outer cylinder (end surface in the axial direction of the outer cylinder)
16B The other end face of the outer cylinder (end face in the axial direction of the outer cylinder)
18 Rubber-like elastic body portion 19A One end surface 19B in the axial direction of the inner cylinder The other end surface 22 in the axial direction of the inner cylinder 22 Holding member 33 Identification protrusion d Position shift amount J Axial direction
M1 First surface M2 Second surface N1, N2 Connection portion O Inner cylinder axis P Inner cylinder axial center Q Outer cylinder axial center

Claims (3)

An inner cylinder, an outer cylinder, and a rubber-like elastic body connecting the inner cylinder and the outer cylinder;
A vibration-proof bushing in which the axial center of the inner cylinder is displaced in the axial direction of the inner and outer cylinders with respect to the axial center of the outer cylinder,
On one end surface and other end surface in the axial direction of the rubber-like elastic body, the inner cylinder identification protrusion is the rubber-like for identifying the center of the axial direction and the direction of the positional deviation between the axial direction of the center of the outer cylinder of the It is vulcanized and molded integrally with an elastic body, and the identification protrusion is disposed on the axially inner side of the axial end surface of the outer cylinder,
A plurality of identification protrusions on one end face side are provided at equal angles around the axis of the inner cylinder, and the identification protrusions on the other end face side are provided in different shapes from the identification protrusions on the one end face side. ,
A stopper sheet as an impact absorbing member for avoiding the axial end of the outer cylinder from colliding with another object is externally fitted to one end of the inner cylinder in the axial direction. Anti-vibration bush attached to the axial end face . The anti-vibration bush according to claim 1, wherein the identification protrusion on the other end surface side is formed in a ring shape concentric with the inner cylinder. The anti-vibration bush according to claim 1 or 2 , wherein a connecting portion between the identification protrusion and a rubber-like elastic body portion around the identification protrusion is formed on a curved surface.

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