JP2006057671A - Blind rivet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blind rivet capable of connecting one attached member with the other attached member so as to rotate mutually around a sleeve after tightening and facilitating tightening work at low cost. <P>SOLUTION: This blind rivet 1 is composed of a rivet main body 2 composed of a hollow sleeve 5 and a flange 6 and a mandrel 3 having a long shaft part 9 and a head part 10 at one end of the shaft part. A peripheral channel 14 extending in the peripheral direction at a position apart slightly from a position where it has length equal to thickness of the attached member from the flange 6 and a vertical channel 15 extending in the axial direction from the peripheral channel to the other end adjacent to the head part are formed on an outer face of the sleeve 5. A rupture part 11 of the shaft part of the mandrel is formed to rupture by force for radially enlarging and deforming a sleeve part from an end part 7 of the sleeve to the peripheral channel 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention comprises a rivet body and a mandrel inserted into a hollow hole in the rivet body, and the sleeve end of the rivet body is expanded and deformed by strongly pulling the mandrel, and the deformed sleeve portion and the flange are used for a panel or the like. The present invention relates to a blind rivet attached to a member to be attached.

  A hollow rivet body comprising a hollow sleeve and a flange at one end of the sleeve, a shaft part longer than the rivet body, and a mandrel having a head having a larger diameter than the shaft part at one end of the shaft part. So that the head part is adjacent to the other end of the sleeve, and the mandrel shaft part is deformed so as to expand the other end of the sleeve by pulling it so strongly that it breaks from the small-diameter fracture part formed in the shaft part. A blind rivet that is attached to a member to be attached by a deformed sleeve end portion and a flange is well known. An example of such a blind rivet is described in JP-A-9-196036 (Patent Document 1). The blind rivet shown in FIG. 1 is sandwiched between two attached members by a sleeve end portion and a flange whose diameter has been deformed and is connected to each other. The blind rivet shown in FIGS. 2 and 3 is engaged with the sleeve end portion of the mounted member which has been enlarged in the blind hole and cooperates with the flange to fix the sleeve body to the mounted member. The male screw part formed in the above is used as an anchor bolt. On the outer surface of the sleeve of the blind rivet of Patent Document 1, a large number of longitudinal grooves extending in the circumferential direction are formed at intervals in the circumferential direction, facilitating the diameter expansion deformation of the sleeve end, The burden of fastening work is lightened.

  The blind rivet described in Patent Document 1 is suitable for connecting attached members such as a plurality of panels to each other. However, for example, when an ejector used to insert or remove a printed circuit board from or to a housing is to be used as a rotating shaft portion that is rotatably fixed to the printed circuit board, the ejector and the rotating board are firmly Since it is difficult to rotate the ejector with respect to the circuit board, it is not suitable for use as a rotating shaft. The blind rivet described in Japanese Utility Model Publication No. 6-78610 (Patent Document 2: Utility Model Registration No. 2607070) is attached to, for example, two attached members of an ejector and a printed circuit board. The other attached member is connected to one attached member so as to be able to rotate around the sleeve after fastening. In this blind rivet, the sleeve is formed thinly between the end portion and the position away from the flange by the thickness of the two attached members, and is more easily deformed than the other sleeve portions. When the mandrel is pulled, the mandrel head first acts on the thin portion and deforms so as to expand the diameter of the thin portion, but the sleeve portions corresponding to the thickness of the two attached members are not deformed. In this state, when the tension is further pulled, the mandrel breaks due to a sudden impact force due to the change in the thickness, and the sleeve portion corresponding to the thickness of the two attached members remains undeformed, and the diameter of the thin portion of the sleeve is increased. The two attached members are connected to each other by the portion and the flange, and the other attached member can be rotated around the sleeve with respect to one attached member.

  Japanese Patent Application Laid-Open No. 2-21011 (Patent Document 3) is similar to the blind rivet of Patent Document 2, in which the sleeve end adjacent to the mandrel head is formed thin, and in addition, the thin sleeve A longitudinal groove is formed in the part to facilitate the diameter expansion deformation of the sleeve end part, thereby facilitating the insertion of the sleeve into the blind hole of the attached member and fixing the rivet body to the attached member. Yes.

  In the blind rivets of Patent Document 2 and Patent Document 3, the sleeve is formed thin at a portion adjacent to the mandrel head. For this reason, equipment and processes for forming the inside of the sleeve portion to be thin by forming a step are required, which is not efficient in terms of productivity and increases the price of blind rivets. Japanese Patent Laying-Open No. 2003-166514 (Patent Document 4) discloses a blind rivet that expands and deforms a sleeve end portion without forming a portion adjacent to a mandrel head thin. In the blind rivet of Patent Document 4, a circumferential groove extending in the circumferential direction is formed on the outer peripheral surface of the sleeve at a position slightly away from the flange at a position having a length equal to the thickness of the mounted member. The sleeve portion from the sleeve end to the circumferential groove is expanded and deformed, but the sleeve portion from the circumferential groove to the flange is ruptured with a force that hardly deforms.

Japanese Patent Laid-Open No. 9-196036 Japanese Utility Model Publication No. 6-078610 (Utility Model Registration No. 2607070) Japanese Patent Laid-Open No. 2-021011 JP 2003-166514 A

  The conventional blind rivets described above still have problems to be solved. When the blind rivet of Patent Document 1 is used as a rotating shaft portion that is rotatably held on a printed circuit board, the ejector and the rotating board are firmly fixed, and the ejector may be rotated with respect to the circuit board. It becomes difficult. The blind rivets of Patent Document 2 and Patent Document 3 require equipment and processes for forming the inside of the end portion of the sleeve to have a stepped shape, and are not efficient in terms of productivity. Raise the price of rivets. The blind rivet of Patent Document 4 is preferable in that it solves the problems of Patent Documents 1 to 3. However, there is room for improvement in that it is difficult to adjust the breaking force of the mandrel so that the sleeve portion from the sleeve end to the circumferential groove is expanded and deformed, but the remaining sleeve portion from the circumferential groove to the flange is not deformed. Yes.

Accordingly, one of the objects of the present invention is to connect a plurality of attached members so that the other attached members can be rotated around the sleeve after fastening with respect to one attached member. Another object of the present invention is to provide a blind rivet that is inexpensive and easy to fasten.
Another object of the present invention is to provide a low-cost blind rivet that can be easily fixed to a member to be attached using a blind hole of the member to be attached.

  In order to achieve such an object, the present invention has a hollow rivet body comprising a hollow sleeve and a flange at one end of the sleeve, a shaft portion longer than the rivet body, and a head portion having a diameter larger than that of the shaft portion at one end of the shaft portion. The mandrel consists of a mandrel, which penetrates the rivet body so that the head is adjacent to the other end of the sleeve, and pulls the mandrel shaft part so strongly as to break from the small-diameter breakage part formed on the shaft part. The other end of the sleeve is deformed to increase its diameter, and a blind rivet is provided that is attached to the attached member by the deformed sleeve end and the flange, and the blind rivet is provided on the outer surface of the sleeve from the flange to the thickness of the attached member. A circumferential groove extending in a circumferential direction at a position slightly apart from a position having a length equal to The broken portion of the mandrel shaft portion is formed so that the sleeve portion from the end portion of the sleeve to the circumferential groove is expanded and deformed, but the sleeve portion from the circumferential groove to the flange is broken by a force that hardly deforms. It is characterized by that.

  By such blind rivets, the end of the sleeve is easily and reliably divided from the longitudinal groove as a starting point, and the end of the divided sleeve is surely expanded radially outward from the circumferential groove in the lateral direction. When the mandrel head reaches the circumferential groove, which is the end point of the longitudinal groove, the resistance to pulling out of the mandrel increases rapidly, so that the end point of the fastening can be surely grasped and the mandrel can be broken at this point. Can be reliably terminated. Accordingly, the diameter of the sleeve portion from the sleeve end portion to the circumferential groove can be reliably expanded and maintained, and the remaining sleeve portion from the circumferential groove to the flange can be maintained without being deformed, and the mandrel breaking force can be easily adjusted. The plurality of attached members are connected by the sleeve portion whose diameter has been deformed and the flange of the rivet body, and the length of the sleeve from the flange to the circumferential groove is longer than the thickness of the attached member. One attached member can rotate around the sleeve relative to the other attached member, and the process and equipment for forming the sleeve of the blind rivet into a thin wall is not required, and a predetermined position on the outer surface of the sleeve is not required. Since it is only necessary to form the vertical groove and the circumferential groove, the manufacture thereof is simple and the blind rivet can be provided at a low price.

  Further, the present invention comprises a hollow rivet body comprising a hollow sleeve and a flange at one end of the sleeve, a shaft part longer than the rivet body, and a mandrel having a head having a diameter larger than the shaft part at one end of the shaft part, The mandrel penetrates the rivet body so that the head is adjacent to the other end of the sleeve, and the shaft end of the mandrel is pulled so strongly that it breaks from the small-diameter breakage formed on the shaft, thereby expanding the other end of the sleeve. A blind rivet that is deformed to have a diameter and is attached to a mounted member by a deformed sleeve end and a flange, and the sleeve is formed on the mounted member, so that the sleeve can be inserted into the blind hole, and the flange contacts the mounted member. The outer surface of the sleeve has a longitudinal groove that extends short in the axial direction from the other end adjacent to the head, and a circumferential groove that extends in the circumferential direction at the end of the longitudinal groove. The rupture portion of the mandrel shaft portion is formed so that the sleeve portion from the end portion of the sleeve to the circumferential groove is expanded and deformed, but the rupture portion is broken with a force that hardly deforms the sleeve portion from the circumferential groove to the flange. A blind rivet is provided.

  Even with such blind rivets, the end of the sleeve is easily and reliably divided starting from the longitudinal groove, and the end of the divided sleeve is reliably expanded radially outward from the circumferential groove in the lateral direction. When the mandrel head reaches the circumferential groove, which is the end point of the longitudinal groove, the resistance to pulling out of the mandrel increases rapidly, so that the end point of fastening can be grasped reliably and the mandrel can be broken at this point. The fastening can be completed reliably. Therefore, the end portion of the sleeve inserted into the blind hole of the attached member is engaged with the blind hole very easily and reliably, and the rivet body is fixed to the attached member. By this fixing, for example, another attached member can be fixed or connected to one attached member. Further, there is no need for a process and equipment for forming the sleeve of the blind rivet into a thin wall, and it is only necessary to form the longitudinal groove and the circumferential groove at a predetermined position on the outer surface of the sleeve, so that the manufacture thereof is simple and the blind rivet is reduced. Can be offered at a price.

  In the blind rivet, a plurality of longitudinal grooves are preferably formed at equal intervals along the outer periphery of the sleeve. Thereby, the division of the sleeve end portion is further facilitated, and the diameter expansion deformation of the divided sleeve end portion is further ensured.

  Hereinafter, one embodiment of the present invention will be described with reference to the drawings. A blind rivet 1 according to an embodiment of the present invention is shown in FIG. FIG. 2 is a cross-sectional view of the blind rivet 1 of FIG. 1 taken along the line II-II. 1 and 2, a blind rivet 1 includes a hollow metal rivet body 2 and a metal mandrel 3 that penetrates the rivet body 2 and is longer than the rivet body 2. For example, the mandrel 3 is made of a hard steel wire, and the rivet body 2 is made of an aluminum alloy.

  The rivet body 2 includes a sleeve 5 and a large-diameter flange 6 at one end of the sleeve 5. The rivet body 2 is formed in a hollow shape so that the mandrel 3 passes therethrough. The end 7 of the sleeve opposite to the flange 6 is open. In the illustrated rivet body 2, the flange 6 is formed in a circular shape, and the sleeve 5 is formed in a cylindrical tubular body. As shown in FIGS. 1 and 2, the mandrel 3 has a shaft portion 9 that is considerably longer than the sleeve 5 and a diameter that is substantially larger than the outer diameter of the end portion 7 of the sleeve 5. The large-diameter head 10 is formed. A broken portion 11 having a smaller diameter than the other shaft portion is formed at a boundary portion between the head portion 10 and the shaft portion 9. The position of the fracture portion 11 is arbitrary, but if it is formed at the position shown in the figure, the mandrel 3 after the fracture can be collected in the collection box of the fastening tool, so that most of the mandrel 3 can be collected, and the collection rate is high. Highly maintainable. The mandrel shaft portion 9 is formed with a deformed portion 13 adjacent to the broken portion 11 and is used for holding the rivet body 2 and the mandrel 3. The mandrel shaft portion 9 has a length that protrudes from the rivet body flange 6 and that the protruding portion can be sufficiently gripped by a gripping member at the tip of a fastening tool (not shown). The tip is tapered so that it can be easily inserted into the tip of the fastening tool.

  In the present invention, a circumferential groove 14 extending in the circumferential direction is formed on the outer surface of the sleeve 5 of the rivet body 2 at a position near the end 7 and away from the end 7. When the circumferential groove 14 is used as a rotating shaft portion that connects a plurality of attached members (see FIG. 4), the position of the circumferential groove 14 is from a position having a length equal to the total thickness of the attached members from the flange 6. It is formed at a slightly separated position. Further, the outer diameter of the sleeve 5 is slightly smaller than the mounting hole so that it can be inserted into the mounting hole of the mounted member and becomes a rotating shaft portion. When the blind rivet 1 is fixed to the blind hole of one attached member and the other attached member is connected or fixed (see FIG. 5) instead of being used as the rotating shaft portion, the circumferential groove 14 should just be formed in the position which can be inserted in the blind hole of one to-be-attached member. In this case, the sleeve 5 is formed so as to have a length and an outer diameter that can be inserted into the blind hole formed on one attached member and that the flange 6 can come into contact with another attached member. In any case, the circumferential groove 14 is provided so as to act as a base point of the diameter expansion deformation of the sleeve 5 by making the portion lower in strength than the other sleeve portions. The circumferential groove 14 can be easily formed at a predetermined position on the outer peripheral surface of the sleeve, for example, by rolling or drawing. Further, as described later, the circumferential groove 14 can be formed together with the vertical groove 15 by a swaging die (see FIG. 3).

  Further, a longitudinal groove 15 extending in the axial direction is formed on the outer surface of the sleeve 5 between the circumferential groove 14 and the end 7 where the mandrel head 10 is adjacent. As shown in FIG. 2, a plurality of the vertical grooves 15 are formed at equal intervals along the outer periphery of the sleeve 5 (in the illustrated embodiment, four at an angular interval of 90 degrees). The longitudinal groove 15 becomes a starting point for dividing the sleeve 5 when a pulling force is applied to the shaft portion 9 of the mandrel 3 and the head portion 10 strongly contacts the end portion 7 of the sleeve 5. Accordingly, the sleeve end portion 7 is easily and reliably divided from the longitudinal groove 15 as a starting point, and the divided sleeve end portion is reliably radially outward with the circumferential groove 14 in the circumferential direction, that is, the lateral direction as a deformation starting point. It will be deformed so that its diameter increases. When the mandrel head 10 reaches the circumferential groove 14 which is the end point of the vertical groove 15, the resistance force against the extraction of the shaft portion 9 of the mandrel 3 increases rapidly, and the end point of fastening can be reliably grasped. At that time, the resistance against pulling out suddenly increases, so that the shaft portion 9 of the mandrel 3 can be broken at the broken portion 11, and the sleeve end portion from the end 7 of the sleeve 5 to the circumferential groove 14 is in the radial direction. The diameter is reliably deformed outward. Accordingly, the rotatable connection of the plurality of attached members (FIG. 4) or the connection of the plurality of attached members using the blind holes can be reliably performed, and the fastening operation can be reliably completed.

  The broken portion 11 of the mandrel shaft portion 9 breaks with a force that causes the sleeve portion from the end 7 of the sleeve 5 to the circumferential groove 14 to expand in diameter, but hardly deforms the sleeve portion from the circumferential groove 14 to the flange 6. It is formed as follows. For example, the breaking force of the breaking portion 11 of the mandrel shaft portion is about 2/3 of the minimum breaking force that expands and deforms the sleeve portion from the circumferential groove 14 to the flange 6 when fastened without a mounted member. Preferably it is selected. Further, the mandrel head 10 is preferably formed as a sloped surface that faces the end 7 of the sleeve 5 of the rivet body 2. The slope shape may be arbitrary, and can be formed in a conical shape, a pyramid shape, or a hemispherical shape.

  As shown in FIG. 3, the circumferential groove 14 and the vertical groove 15 can be formed using a swaging die. In FIG. 3, the swaging die 17 divided into four parts is shown in a cross section at a portion where the circumferential groove 14 is formed. Inside the four swaging dies 17, the sleeve 5 through which the mandrel shaft portion 9 passes is disposed. Each swaging die 17 has a longitudinal groove forming portion 18 extending in the axial direction (direction perpendicular to the paper surface) for forming the longitudinal groove 15 and a quarter-circular circumferential groove forming portion 19 for forming the circumferential groove 14. Is provided. In the formation of the circumferential groove 14 and the longitudinal groove 15, the sleeve 5 is positioned at a predetermined position inside the four swaging dies 17, and each swaging die 17 has a radius on the outer surface of the sleeve 5 by a pressure welding tool or a pressure welding device. It is pressed strongly and evenly inward in the direction. As a result, the circumferential groove 14 and the longitudinal groove 15 are formed together at a predetermined position on the outer surface of the sleeve 5.

  As shown in FIG. 4, the blind rivet 1 is used to remove the first attached member 21 such as an ejector from the second attached member 22 such as a printed circuit board. The mounting member 22 can be connected so as to be rotatable about the sleeve 5 as an axis. The circumferential groove 14 is formed at a position separated from the flange 6 by a length that ensures a gap for rotation that is longer than the combined thickness of the first mounted member and the second mounted member. The mounting members 21 and 22 are already formed with mounting holes for receiving the sleeve 5. The blind rivet 1 is inserted into the mounting hole in a state in which the mounting holes are matched to support both mounted members. With the head 10 of the mandrel 3 at the top, the sleeve 5 of the rivet body 2 is inserted into the mounting holes of the mounted members 21 and 22 until the flange 6 contacts the mounted member 21. The blind rivet 1 may be inserted into the mounting hole by hand, or may be inserted with the mandrel shaft portion 9 of the blind rivet 1 held by the fastening tool. When the blind rivet 1 is held by the fastening tool, the state remains as it is, and when the blind rivet 1 is inserted into the mounting hole by hand, the shaft 9 portion of the mandrel 3 is held at the tip of the fastening tool. Then, the fastening tool is operated and pulled so strongly that the mandrel shaft portion 9 is broken at the broken portion 11.

  When the mandrel shaft portion 9 is pulled, the mandrel head portion 10 comes into strong contact with the end portion 7 of the sleeve 5, and the sleeve 5 starts to be divided along the longitudinal groove 15 from the longitudinal groove 15, It ends when it reaches 14. Further, the end portion of the divided sleeve 5 is deformed by the mandrel head 10 that is in pressure contact so as to expand radially outward from the circumferential groove 14 as a base point. When the mandrel head 10 reaches the circumferential groove 14 that is the end point of the longitudinal groove 15, the resistance force against the extraction of the shaft portion 9 of the mandrel 3 increases rapidly. By increasing the resistance force, the operator increases the force for pulling out the mandrel shaft portion 9, and the strong pulling force acts on the broken portion 11 to break the mandrel shaft portion 9 at the broken portion 11. As described above, the resistance to pulling out increases rapidly at the time when the fastening operator is finished, so that the fastening work can be reliably finished. When the fastening operation is completed, as shown in FIG. 4, the first attached member 21 and the second attached member 22 are sandwiched between the flange 6 and the diameter-enlarged deformed portion 23 of the sleeve end, and the flange The two mounted members are connected to each other by the rivet body 2 having the diameter 6 and the diameter-enlarged deformation portion 23 of the sleeve 5.

  On the other hand, the deformation of the end portion of the sleeve 5 stops at the peripheral groove 14 portion of the sleeve 5, and the sleeve portion on the flange 6 side beyond that is hardly deformed. The fracture portion 11 is formed so that the sleeve portion from the end portion 7 of the sleeve 5 to the circumferential groove 14 is expanded and deformed, but the sleeve portion from the circumferential groove 14 to the flange 6 is fractured with a force that hardly deforms. ing. Therefore, the sleeve 5 of the blind rivet 1 is not deformed by expanding in the thickness portion of the attached member (the portion between the circumferential groove 14 and the flange 6). Further, the length of the sleeve 5 between the circumferential groove 14 and the flange 6 is longer than the total thickness of the first mounted member 21 and the second mounted member 22 and is long enough to ensure the rotation gap 25. It has become. For example, when the plate thickness is 4 mm, the circumferential groove 14 is formed at a position 5 mm from the flange 6. Accordingly, not only the first attached member 21 such as an ejector and the second attached member 22 such as a printed circuit board are connected, but the first attached member 21 is sleeved with respect to the second attached member 22. 5 can be rotated about the rotation axis. Further, since the diameter of the sleeve portion on the end portion 7 side from the circumferential groove 14 is reliably expanded, both the attached members can be reliably connected. Since the blind rivet 1 only needs to be formed with the circumferential groove 14 and the longitudinal groove 15 in the sleeve 5, its manufacture is simple and the blind rivet can be provided at a low price.

  As shown in FIG. 5, the blind rivet 1 can be used to attach the first attached member 27 having the blind hole 26 to the second attached member 29. The blind rivet 1 is inserted into the mounting hole and the blind hole 26 in a state where the mounting holes of the second mounted member 29 are aligned with the blind holes 26 of the first mounted member 27 and both the mounted members are held. With the head 10 of the mandrel 3 at the head, the sleeve 5 of the rivet body 2 is inserted into the mounting hole of the second mounted member 29 and the blind of the first mounted member 27 until the flange 6 contacts the second mounted member 29. Insert into hole 26. After the insertion, the fastening tool is operated to pull the mandrel shaft 9 so strongly that it breaks at the broken portion 11. The mandrel head 10 strongly abuts the sleeve 5 against the end 7, the sleeve 5 is divided along the longitudinal groove 15 from the longitudinal groove 15, and the end portion of the divided sleeve 5 is based on the circumferential groove 14. The diameter-enlarged deformed portion 30 is strongly engaged with the side wall of the blind hole 26. When the mandrel head 10 reaches the circumferential groove 14 which is the end point of the vertical groove 15, the resistance force against the extraction of the shaft portion 9 of the mandrel 3 increases abruptly, and the fastening operation can be reliably completed. When the fastening operation is completed, as shown in FIG. 5, the diameter-enlarged deformed portion 30 at the end of the sleeve 5 is firmly fixed to the blind hole 26 of the first attached member 27, and the other flange 6 is the second attached member 29. Therefore, the second mounted member 29 is firmly connected to the first mounted member 27. In other words, the blind rivet 1 uses the blind hole 26 of the first attached member 27 as an anchor to fix the second attached member 29 easily and reliably. The mandrel head 10 is left in the blind hole 26 after the mandrel 3 is broken.

It is a front view of a blind rivet concerning one embodiment of the present invention, and is a figure showing a rivet body by half section. It is the II-II sectional view taken on the line of the blind rivet of FIG. It is a cross-sectional view of a swaging die capable of forming a circumferential groove and a longitudinal groove. FIG. 3 is a half sectional view showing a state after a plurality of attached members are rotatably connected using the blind rivet of FIG. 1. It is a half sectional view which shows the state after connecting another to-be-attached member to the to-be-attached member with a blind hole using the blind rivet of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blind rivet 2 Rivet body 3 Mandrel 5 Sleeve 6 Flange 7 Sleeve end 9 Mandrel shaft 10 Mandrel head 11 Broken part 13 Second small diameter part 14 Circumferential groove 15 Vertical groove 17 Swaging die 18 Vertical groove forming part 19 Groove forming portions 21, 27 First attached member 22, 29 Second attached member 23 Diameter expansion deformed portion 25 of sleeve 25 Clearance hole 26 Blind hole 30 Diameter expansion deformed portion of sleeve

Claims (3)

A hollow rivet body composed of a hollow sleeve and a flange at one end of the sleeve, a shaft part longer than the rivet body, and a mandrel having a head having a larger diameter than the shaft part at one end of the shaft part, The other end of the sleeve is pulled through the rivet body so that the head is adjacent to the other end of the sleeve, and the shaft of the mandrel is pulled so strongly as to be broken from a small-diameter fracture portion formed in the shaft. A blind rivet that is attached to a member to be attached by the deformed sleeve end and the flange,
On the outer surface of the sleeve, a circumferential groove extending in the circumferential direction at a position slightly away from the flange having a length equal to the thickness of the attached member, and from the circumferential groove to the other end adjacent to the head A longitudinal groove extending in the axial direction is formed, and the fracture portion of the mandrel shaft portion deforms the diameter of the sleeve portion from the end portion of the sleeve to the circumferential groove, but the sleeve from the circumferential groove to the flange A blind rivet characterized by being formed so as to be broken by a force that hardly deforms the portion. A hollow rivet body composed of a hollow sleeve and a flange at one end of the sleeve, a shaft part longer than the rivet body, and a mandrel having a head having a larger diameter than the shaft part at one end of the shaft part, The other end of the sleeve is pulled through the rivet body so that the head is adjacent to the other end of the sleeve, and the shaft of the mandrel is pulled so strongly as to be broken from a small-diameter fracture portion formed in the shaft. A blind rivet that is attached to a member to be attached by the deformed sleeve end and the flange,
The sleeve has a length and an outer diameter so that the sleeve can be inserted into the blind hole formed on the attached member and the flange can contact the attached member, and the outer surface of the sleeve has the other end adjacent to the head. And a circumferential groove extending in the circumferential direction at the end of the longitudinal groove, and the broken portion of the mandrel shaft portion is a sleeve from the end of the sleeve to the circumferential groove. A blind rivet characterized in that it is formed so as to be ruptured with a force that deforms the diameter of the sleeve but hardly deforms the sleeve from the circumferential groove to the flange.   3. The blind rivet according to claim 1, wherein a plurality of the longitudinal grooves are formed at equal intervals along the outer periphery of the sleeve.

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