JP2009187826A - Shielded connector, and sleeve member used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shielded connector capable of preventing deformation in connecting a shielded wire to the shielded connector, and to provide a sleeve member used for it. <P>SOLUTION: In the shielded connector 1 where an inner conductor terminal 20 is connected to a terminal of a signal conductor 12 of a shielded wire 10 covered with a shield conductor 16 through an insulator 14 around the signal conductor 12, a tubular sleeve member 30 is inserted between the shield conductor 10 and the insulator 14, and an outer conductor terminal 50 is crimped and connected to the shield conductor 10, projecting parts (vertexes) 34a and 34b projecting outward in a direction crossing the crimp direction of the outer conductor terminal 50 through an axis of the shield wire 10 are formed on the outer peripheral surface 32 of the sleeve member 30. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a shield connector and a sleeve member used therefor, and more specifically, is inserted between an insulator and a shield conductor in order to prevent deformation of the insulator of the shielded electric wire by crimping (caulking) of an outer conductor terminal. And a shield connector provided with such a sleeve member.

  In an electric wire used for transmission of a high-speed, high-frequency electric signal, the periphery of the signal conductor is covered with an insulator such as polyethylene in order to reduce the amount of noise generated from the signal, the amount of signal attenuation, and the like. In recent years, in order to further reduce the amount of noise and attenuation, a material in which the effective relative permittivity of the insulator is reduced by foaming the insulator (hereinafter sometimes referred to as a foamed insulator) is often used. ing.

  A shielded electric wire using such an insulator, particularly a foamed insulator, is easily crushed and is not suitable for connection with a terminal (outer conductor terminal) by crimping. Therefore, for example, as described in Patent Document 1 below, a configuration in which a foamed insulator is prevented from being crushed by inserting a metallic cylindrical sleeve member between the insulator and the shield conductor (braid). Are known.

JP 2006-302824 A

  However, even when the sleeve member is inserted in this manner, depending on the pressure bonding conditions, the sleeve member itself may be deformed and bite into the foamed insulator. FIG. 7 is a diagram schematically showing a cross section when an outer conductor terminal is crimped to a shield conductor using a conventional sleeve member.

  As shown in FIG. 7A, the outer conductor terminal 102 is pressed in the vertical direction (in the direction of the white arrow) by lowering the crimper 108 with respect to the outer conductor terminal 102 placed on the anvil 106. As a result, the outer conductor terminal 102 tends to expand (crush) from side to side, but the side surface of the outer conductor terminal 102 is pressed by the side walls 108a and 108b of the crimper 108 as shown in FIG. 7B. Therefore, an inward force (in the direction of the black arrow) is received by the reaction. Then, the side surface of the sleeve member 100 receiving the inward force may not be able to withstand the force and may be deformed (buckled) inward (in the axial direction of the shielded electric wire). Therefore, when the deformation amount of the sleeve member 100 is large, there is a problem that the sleeve member 100 bites into the foamed insulator 104 and a short circuit between the signal conductor 110 and the shield conductor 112 occurs.

  Problems to be solved by the present invention include a sleeve member that can prevent deformation when connecting a shielded wire to a shield connector, and a signal conductor and shield due to deformation of the sleeve member by providing such a sleeve member. An object of the present invention is to provide a shield connector capable of preventing the occurrence of problems such as a short circuit with a conductor.

  In order to solve the above-described problems, the shield connector according to the present invention includes an inner conductor terminal connected to an end of the signal conductor of a shielded wire in which a shield conductor is covered with an insulator around the signal conductor, and the shield In a shield connector in which an outer conductor terminal is crimped to a conductor, a cylindrical sleeve member is inserted between the insulator and the shield conductor, and an outer peripheral surface of the sleeve member has an outer conductor terminal. The gist is that an overhanging portion that protrudes outward is formed in a direction crossing the crimping direction.

  In this case, a cross section of the outer peripheral surface of the sleeve member is formed in a polygon, and the projecting portion is two vertices of the polygon, or a cross section of the outer peripheral surface of the sleeve member is formed in a circle or an ellipse. A preferable example is one in which a protruding portion serving as the protruding portion is formed on the outer peripheral surface.

  In this case, it is more preferable that the inner peripheral surface of the sleeve member has a circular cross section.

  On the other hand, in the sleeve member according to the present invention, an inner conductor terminal is connected to an end of the signal conductor of a shielded wire in which a shield conductor is covered around the signal conductor via an insulator, and the outer conductor terminal is connected to the shield conductor. Is inserted between the insulator and the shield conductor in the shield connector to be crimped, and the outer peripheral surface of the shield connector projects outwardly in a direction crossing the crimping direction of the outer conductor terminal. The gist is that the protruding portion is formed.

  In this case, the sleeve member has a polygonal cross section on the outer peripheral surface, and the projecting portion is two vertices of the polygon, or a cross section on the outer peripheral surface is formed in a circular or elliptical shape. A suitable example is one in which the surface is provided with a protruding portion serving as the overhanging portion.

  In this case as well, it is more desirable that the inner peripheral surface of the sleeve member has a circular cross section.

  According to the shield connector of the present invention, the overhanging portion that protrudes outward in the direction intersecting the crimping direction of the outer conductor terminal is provided on the outer peripheral surface of the sleeve member interposed between the insulator and the shield conductor. As a result, the rigidity against the force in the axial direction of the shielded electric wire from the side surface of the sleeve member at the projecting portion is improved. Therefore, the sleeve member will not be deformed (buckled) inward even if it receives an inward force in the axial direction of the shielded electric wire from the side surface of the sleeve member during crimping of the outer conductor terminal. It is possible to prevent problems such as a short circuit between the signal conductor and the shield conductor caused by biting into the insulator.

  In this case, if the sleeve member has such a shape that the outer peripheral surface has a polygonal shape, it is inserted between the insulator and the shield conductor so that the two apexes of the polygon correspond to the overhanging portion. Thus, the rigidity of the sleeve member with respect to the force in the axial direction of the shielded electric wire from the side surface is naturally improved, and deformation of the sleeve member to the inside when the outer conductor terminal is crimped is effectively prevented.

  In addition, when the cross section of the outer peripheral surface is not a sleeve member having a polygonal shape but a circular or elliptical cross section, the protruding portion is in a direction crossing the crimping direction of the outer conductor terminal on the outer peripheral surface. By being formed, it is possible to improve the rigidity of the sleeve member against the force in the axial direction of the shielded electric wire from the side surface of the sleeve member, and to prevent the inner deformation of the sleeve member when the outer conductor terminal is crimped. be able to.

  In these cases, if the cross section of the inner peripheral surface of the sleeve member is formed in a circular shape, there will be no gap between the insulator and the inner peripheral surface of the sleeve member. The change in the characteristic impedance of the shield connector due to the change in the inner diameter of the terminal is effectively prevented.

  Further, according to the sleeve member of the present invention, the overhanging portion that protrudes outward in the direction intersecting with the crimping direction of the outer conductor terminal is provided on the outer peripheral surface of the sleeve member interposed between the insulator and the shield conductor. By providing, the rigidity with respect to the force to the axial direction of a shielded electric wire from the side surface of a sleeve member improves in the overhang | projection site | part. Therefore, the sleeve member will not be deformed (buckled) inward even if it receives an inward force in the axial direction of the shielded electric wire from the side surface of the sleeve member during crimping of the outer conductor terminal. It is possible to prevent problems such as a short circuit between the signal conductor and the shield conductor caused by biting into the insulator.

  In this case, if the sleeve member has such a shape that the outer peripheral surface has a polygonal shape, it is inserted between the insulator and the shield conductor so that the two apexes of the polygon correspond to the overhanging portion. Thus, the rigidity of the sleeve member with respect to the force in the axial direction of the shielded electric wire from the side surface is naturally improved, and deformation of the sleeve member to the inside when the outer conductor terminal is crimped is effectively prevented.

  In addition, when the cross section of the outer peripheral surface is not a sleeve member having a polygonal shape but a circular or elliptical cross section, the protruding portion is in a direction crossing the crimping direction of the outer conductor terminal on the outer peripheral surface. By being formed, it is possible to improve the rigidity of the sleeve member against the force in the axial direction of the shielded electric wire from the side surface of the sleeve member, and to prevent the inner deformation of the sleeve member when the outer conductor terminal is crimped. be able to.

  In these cases, if the cross section of the inner peripheral surface of the sleeve member is formed in a circular shape, there will be no gap between the insulator and the inner peripheral surface of the sleeve member. If a sleeve member is used, a change in the characteristic impedance of the shield connector due to a change in the inner diameter of the outer conductor terminal is effectively prevented.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram for explaining the configuration of the shield connector 1 according to the first embodiment of the present invention. Specifically, the state where the shield connector 1 is connected to the end of the shielded electric wire 10 is shown. It is a disassembled perspective view.

  A shielded electric wire 10 shown in FIG. 1 includes a signal conductor 12 in which a plurality of metal strands are bundled as a transmission path for an electric signal or the like. The periphery of the signal conductor 12 is covered with an insulator 14 made of a foamed resin obtained by foaming a resin such as polyethylene. By interposing such an insulator 14, the signal transmission speed of the shielded electric wire 10 is improved and the transmission loss is reduced. The outer periphery of the insulator 14 is covered with a shield conductor 16 (braid) in which a plurality of strands are knitted, and the outer peripheral surface of the shield conductor 16 is further covered with a sheath 18 to form the shielded electric wire 10. Has been.

  The shield connector 1 to which the shielded electric wire 10 is connected protects the inner conductor terminal 20 electrically connected to the signal conductor 12, the outer conductor terminal 50 electrically connected to the shield conductor 16, and the insulator 14. And a sleeve member 30 (first sleeve member).

  The inner conductor terminal 20 is formed by pressing a metal plate, and plays a role of connecting signal conductors by connecting to an inner conductor terminal of a mating connector (not shown). As can be seen from FIG. 1, the inner conductor terminal 20 is connected to the signal conductor 12 that is peeled and exposed for a predetermined length.

  The outer conductor terminal 50 is formed by pressing a metal plate, and has a fitting cylindrical portion 52 formed in a substantially cylindrical shape opened in the front-rear direction and a shield positioned at the rear end of the fitting cylindrical portion 52. It consists of a conductor crimping part 54 and a sheath crimping part 56 located at the rear end of the shield conductor crimping part 54.

  The fitting cylinder part 52 which comprises the outer conductor terminal 50 has the dielectric material 40 in which the inner conductor terminal 20 is inserted. The dielectric 40 is formed of a resin insulating material having a predetermined dielectric constant, and plays a role of maintaining the inner conductor terminal 20 in an insulated state from the outer conductor terminal 50. The shield conductor crimping portion 54 includes a pair of shield conductor crimping pieces 541 and 542, and the outer conductor terminal 50 is electrically connected to the shield conductor 16 by crimping the shield conductor 16 with the shield conductor crimping pieces 541 and 542. Will be. Details of the connection between the two by this crimping will be described later. The sheath crimping portion 56 includes a pair of sheath crimping pieces 561 and 562. The sheath crimping pieces 561 and 562 crimp the sheath 18 of the shielded electric wire 10 so that the outer conductor terminal 50 (shield connector 1) is mechanical. Are connected to the shielded electric wire 10.

  The sleeve member 30 is a metal cylindrical member. FIG. 2 shows an external perspective view in which the sleeve member 30 is enlarged. As shown in FIG. 2, in this embodiment, the sleeve member 30 is formed so that the outer peripheral surface 32 has a hexagonal cross-sectional shape. Then, the sleeve member 30 is inserted between the insulator 14 and the shield conductor 16 described above, and the conductor crimping pieces 541 and 542 of the outer conductor terminal 50 are crimped to the shield conductor 16.

  FIG. 3 is a cross-sectional view for sequentially explaining how the crimping pieces 541 and 542 of the outer conductor terminal 50 are crimped. As shown in FIG. 3A, the shield conductor crimping crimper 70 (hereinafter simply referred to as “crimper 70”) has a left-right asymmetric wall shape formed by connecting two peaks having different heights. Specifically, a relatively shallow recess 701 is formed on the right side and a relatively deep recess 702 is formed on the left side as viewed in FIG. 3, and a protrusion 71 is formed at the center thereof. Further, the distance between the left and right side walls 70a, 70b of the crimper 70 is formed substantially the same as the distance between the conductor crimping pieces 541, 542.

  The shield conductor crimping anvil 72 (hereinafter simply referred to as anvil 72) is a member serving as a base on which the outer conductor terminal 50 is placed during crimping. As can be seen from FIG. 3, the anvil 72 is formed in a curved shape with a predetermined curvature so that the outer conductor terminal 50 can be placed in a stable state.

  As shown in FIG. 3B, the crimping process of the outer conductor terminal 50 is performed by pressing the crimper 70 with a predetermined pressure against the outer conductor terminal 50 placed on the anvil 72. Specifically, when the crimper 70 is lowered, the one conductor crimping piece 541 is first pressed against the shallow depression 701 of the crimper 70 and begins to bend inward. When the crimper 70 is further lowered, the other conductor crimping piece 542 is pressed by the deep recess 702 of the crimper 70 and begins to bend inward. That is, by making the crimper 70 have such a left-right asymmetric shape, the timings at which the conductor crimping pieces 541 and 542 are bent at the time of crimping are shifted. Due to this timing shift, it is possible to prevent the crimping defects from occurring due to the tips of the conductor crimping pieces 541 and 542 abutting each other during crimping.

  The tip of the conductor crimping piece 541 that has begun to be bent first is guided by the protruding portion 71 near the center of the crimper 70 and guided downward. Furthermore, the tip of the conductor crimping piece 542 that has started to bend later is led to the protruding portion 71 and bent so as to overlap the conductor crimping piece 541.

  Thereafter, as shown in FIG. 3C, when the crimper 70 is further lowered, the shield conductor 16 is sandwiched between the conductor crimping pieces 541 and 542 and the sleeve member 30 thus pressed. The crimping process is completed.

  In this crimping process, the outer conductor terminal 50 that has received pressure from the crimper 70 receives pressure in the vertical direction in FIG. 3 (in the direction of the white arrow shown in FIG. 3B), and therefore tends to spread left and right (crushed) However, since it is pressed against the left and right side walls 70a, 70b of the crimper 70, it receives an inward force (in the direction of the black arrow shown in FIG. 3C) by its reaction.

  With respect to such an inward force, in this embodiment, the sleeve member 30 has an outer peripheral surface 32 formed in a hexagonal shape, of which two apexes 34a and 34b (corresponding to the overhanging portion in the present invention). Is positioned in a direction (horizontal direction in FIG. 3) that passes through the axis of the shielded electric wire 10 and perpendicularly intersects the crimping direction by the crimper 70. If the sleeve member 30 is arranged in this manner, the rigidity against the force in the axial direction from the side surface of the sleeve member 30 is increased, so that the possibility of the sleeve member 30 being deformed (buckled) inward can be reduced. it can. Therefore, as in the case where a conventional sleeve member formed in a cylindrical shape is used, the sleeve member is deformed inward and bites into the insulator 14, and the signal conductor 12 and the shield conductor 16 are short-circuited. Can be prevented.

  The sleeve member 30 is inserted by using an automatic machine to ensure that the two apexes 34a and 34b pass in a predetermined direction (the direction passing through the axis of the shielded electric wire 10 and perpendicular to the crimping direction by the crimper 70). ). Further, the cross-sectional shape of the outer peripheral surface 32 of the sleeve member 30 is not necessarily limited to a hexagon. If the cross-sectional shape is a polygon having an even number of vertices, such as a quadrangular, octagonal, and decagonal shape, two vertices are used as overhangs, and these are passed through the axis of the shielded wire 10 and crimped by the crimper 70. The same effect as described above can be obtained by pressing in the direction perpendicular to the direction (horizontal direction in FIG. 3). Further, even if the cross-sectional shape is a polygon having an odd number of vertices (such as a pentagon), if the two vertices are arranged so as to project outward, the side surface of the sleeve member 30 extends in the axial direction. The rigidity with respect to the force can be increased.

  Next, a shield connector according to a second embodiment of the present invention will be described. The shield connector according to the second embodiment is different from the shield connector 1 according to the first embodiment in the configuration of the sleeve member. Accordingly, the same reference numerals are used for other identical components, and detailed description thereof is omitted.

  FIG. 4 is an external perspective view of a sleeve member 60 (second sleeve member) included in the shield connector according to the second embodiment. As shown in FIG. 4, in this embodiment, the sleeve member 60 has an outer peripheral surface 62 having an elliptical cross section, and projecting portions 64 a and 64 b (in the present invention) at two opposing positions on the outer peripheral surface 62. Corresponding to the overhanging portion). The method for forming the projecting portions 64a and 64b is not limited to a specific method, but may be formed by a method such as crushing a predetermined amount of the side surface of the cylindrical pipe with a press.

  Even when the sleeve member 60 is configured in such a shape, the same effect as that of the first embodiment can be expected in the crimping process of the outer conductor terminal 50. FIG. 5 is a cross-sectional view showing a state in which the conductor crimping pieces 541 and 542 of the outer conductor terminal 50 according to the second embodiment are crimped. The crimper 70 and the anvil 72 used in this crimping step are the same as those described in the first embodiment.

  As described above, when the crimper 70 is lowered and the outer conductor terminal 50 is pressed in the vertical direction (in the direction of the white arrow), the outer conductor terminal 50 tries to spread (trims) to the left and right. Since it is pressed against the left and right side walls 70a, 70b, it receives an inward force (in the direction of the black arrow) by its reaction.

  In this embodiment, the sleeve member 60 has protrusions 64a and 64b formed on the outer peripheral surface 62 against such an inward force, and the protrusions 64a and 64b are connected to the shielded electric wire 10. Is located in a direction (horizontal direction in FIG. 5) perpendicular to the crimping direction by the crimper 70. If the sleeve member 30 is arranged in this manner, the rigidity with respect to the force in the axial direction from the side surface of the sleeve member 30 is increased. Therefore, as in the first embodiment, the sleeve member 30 is deformed inward (buckling). It is possible to reduce the risk of doing so.

  In the second embodiment, it has been described that the outer circumferential surface 62 of the sleeve member 60 has an elliptical cross section. However, the sleeve member 60 may have another shape such as a circle. Further, the protruding portions 64a and 64b are not necessarily limited to the shapes as shown in FIG.

  As described above, according to the shield connector (sleeve member) according to the present embodiment, when the conductor crimping pieces 541 and 542 of the outer conductor terminal 50 are crimped, the sleeve member is the axial core of the shielded electric wire 10 from the side surface. Although the force is received in the direction, the overhanging portions (polygonal apexes 34a and 34b and projecting portions 64a and 64b) formed so as to project outwardly increase the rigidity in the direction of receiving the force. Therefore, the possibility that the sleeve member is deformed (buckled) inward and bites into the insulator 14 can be reduced. Therefore, the occurrence of problems such as a short circuit between the signal conductor 12 and the shield conductor 16 is reduced as compared with the case where a conventional sleeve member having a circular cross section is used.

  Here, a preferred modification of the present embodiment (modification according to the first embodiment) will be described with reference to FIG. 6A is an external perspective view of a sleeve member 90 (third sleeve member) according to the modification, and FIG. 6B is a diagram of the outer conductor terminal 50 when the sleeve member 90 according to the modification is used. 6 is a cross-sectional view of a conductor crimping portion 54. FIG.

  As described above, in the present embodiment, the protruding portions (vertices) 94a and 94b are provided on the outer peripheral surface 92 of the sleeve member 90, thereby preventing deformation during crimping. Further, in this modification, as shown in FIG. 6A, unlike the shape of the outer peripheral surface 92, the cross section of the insertion opening into which the insulator 14 is inserted, that is, the cross section of the inner peripheral surface 96 of the sleeve member 90 is circular. Is formed.

  As can be seen from FIG. 6B, by forming the cross section of the inner peripheral surface 96 of the sleeve member 90 in this way, a large gap is formed between the insulator 14 and the inner peripheral surface 96 of the sleeve member 92. It does not occur. The characteristic impedance of the shield connector 1 is known to be affected by a change in the inner diameter of the outer conductor terminal 50. However, when the cross-sectional shape of the inner peripheral surface is formed in a polygon or the like, the insulator 14 and the sleeve member 92 are used. A gap may be formed between the inner peripheral surface 96 and the inner diameter of the outer conductor terminal 50. On the other hand, in this modification, by preventing a gap from being formed between the sleeve member 92 and the insulator 14, the inner diameter is prevented from changing, and the impedances of the shield connector 1 and the shielded electric wire 10 to be connected are prevented. Can be avoided. Thereby, the amount of noise generated from the signal and the amount of transmission loss of the signal can be reduced.

  As described above, the sleeve member 90 is a modified example of the sleeve member 30 described in the first embodiment (the outer peripheral surface has a polygonal cross-sectional shape), but this technical idea is the first. The present invention can also be applied to the sleeve member 60 described in the second embodiment.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the shield connector having the outer conductor terminal and the sleeve as separate members has been described. However, the present invention can also be applied to a shield connector in which the outer conductor terminal and the sleeve are integrated.

  Moreover, in the said embodiment, although demonstrated that the insulator of a shielded electric wire consists of a foamed insulator which foamed resin, such as a polystyrene, generally a foamed insulator is crushed easily and the significance of applying this invention is great. That is, it is not necessarily applied to a shielded electric wire using a foamed insulator. That is, the technical idea of the present invention can be applied to an insulator that is not foamed.

  The shield connector and the sleeve member according to the present invention can be suitably used for a harness or the like of a device (for example, a home appliance or an automobile) that transmits a high-frequency electric signal.

It is a disassembled perspective view for demonstrating the structure of the shield connector which concerns on 1st embodiment of this invention. It is the external appearance perspective view which expanded and showed the 1st sleeve member with which the shield connector shown in FIG. 1 is provided. It is sectional drawing shown in order to demonstrate a mode that the conductor crimping piece of an outer conductor terminal was crimped | bonded to the shield conductor using the 1st sleeve member shown in FIG. 1 and FIG. It is the external appearance perspective view which expanded and showed the 2nd sleeve member with which the shield connector which concerns on 2nd embodiment of this invention is provided. It is sectional drawing shown in order to demonstrate a mode that the conductor crimping piece of an outer conductor terminal was crimped | bonded to a shield conductor using the 2nd sleeve member shown in FIG. FIG. 6A is an external perspective view of the sleeve member according to the modification, and FIG. 6B is a cross-sectional view of the conductor crimping portion of the outer conductor terminal when the sleeve member according to the modification is used. It is sectional drawing shown in order to demonstrate a mode that an outer conductor terminal was crimped | bonded to a shield conductor using the conventional sleeve member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shield connector 10 Shield electric wire 12 Signal conductor 14 Insulator 16 Shield conductor 20 Inner conductor terminal 30 1st sleeve member 32 Outer peripheral surface 34a, 34b Vertex (overhang | projection part)
50 Outer conductor terminal 60 Second sleeve member 62 Outer peripheral surface 64a, 64b Projection (overhang)
90 Third sleeve member 96 inner peripheral surface

Claims (8)

  In a shield connector in which an inner conductor terminal is connected to an end of the signal conductor of a shielded wire that is covered with a shield conductor through an insulator around the signal conductor, and an outer conductor terminal is crimped to the shield conductor, A cylindrical sleeve member is inserted between the insulator and the shield conductor, and an outer peripheral surface of the sleeve member has an overhang portion projecting outward in a direction intersecting with the crimping direction of the outer conductor terminal. A shielded connector characterized by being formed.   The shield connector according to claim 1, wherein a cross section of the outer peripheral surface of the sleeve member is formed in a polygon, and the projecting portion is two apexes of the polygon.   2. The shield connector according to claim 1, wherein a cross-section of an outer peripheral surface of the sleeve member is formed in a circular shape or an oval shape, and a protruding portion serving as the projecting portion is formed on the outer peripheral surface.   The shield connector according to any one of claims 1 to 3, wherein a cross section of an inner peripheral surface of the sleeve member is formed in a circular shape.   The insulation in a shield connector in which an inner conductor terminal is connected to an end of the signal conductor of a shielded electric wire that is covered with an insulating conductor around the signal conductor, and an outer conductor terminal is crimped to the shield conductor. A sleeve member inserted between a body and the shield conductor, and an outer peripheral surface of the sleeve member is formed with an overhanging portion projecting outward in a direction intersecting the crimping direction of the outer conductor terminal. A featured sleeve member.   The sleeve member according to claim 5, wherein a cross-section of an outer peripheral surface is formed in a polygon, and the projecting portion is two apexes of the polygon.   The sleeve member according to claim 5, wherein a cross-section of the outer peripheral surface is formed in a circular shape or an elliptical shape, and a protruding portion serving as the protruding portion is formed on the outer peripheral surface.   The sleeve member according to any one of claims 5 to 7, wherein an inner peripheral surface has a circular cross section.

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