JP3484086B2 - Fastener - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastener for fastening a plurality of members to each other, and more particularly to a fastener for fastening using blind holes formed in the members.

[0002]

2. Description of the Related Art Generally, a rivet is known as a fastener for fastening a plurality of members to each other. Rivets are used for various purposes as semi-permanent fasteners because of their good workability, and in recent years, even in electronic devices,
Used for fixing parts. This kind of fastener has
Using only rivets, plastic deformation is performed by directly applying an external force to one end of the rivet, and by inserting a rod-shaped mandrel into a cylindrical rivet and applying an external force to the mandrel to transmit the deformation force to the rivet There is something to transform.

Among fasteners in which a rod-shaped mandrel is inserted into a tubular rivet, a fastener disclosed in Japanese Utility Model Publication No. 5-12727 is known as a fastener in which a part of the mandrel remains in the rivet. ing. FIG. 12 shows an example of this type of fastener, and the rivet 1 is composed of a cylindrical main body 1a and a flange 1c formed at one end 1b of the main body 1a. Mandrel 2
Is composed of a head portion 2a that abuts on the opening end 1d of the rivet 1 opposite to the flange 1b, and a shaft portion 2b that extends from the head portion 2a and is inserted into the through hole 1e of the rivet 1. ing.

A notch 2c is formed in the shaft portion 2b of the mandrel 2 at a position which is left in the rivet at the time of fastening, substantially in the center in the longitudinal direction, along the cross-sectional direction. In the fastener described above, a plurality of members are fastened to each other as shown below. That is, first, as shown in FIG. 13, the rivet 1 into which the mandrel 2 is inserted is inserted into the hole 5 formed through the fastening members 3 and 4 from the head 2 a side of the mandrel 2.

Next, by pulling the shaft portion 2b of the mandrel 2 while pressing the flange 1c of the rivet 1,
The head 2a of the mandrel 2 presses the open end 1d of the rivet 1. By this pressing, the main body portion 1a of the rivet 1 is plastically deformed, and the through hole 5 and the shaft portion 2b of the mandrel 2 are pressed in the cross sectional direction. At the same time, the open end 1 of the main body 1a
The d side is plastically deformed, and a buckling portion 1f larger than the inner diameter of the through hole 5 is formed at the open end 1d of the main body portion 1a.

Further, by pulling the mandrel 2, the shaft portion 2b of the mandrel 2 is broken from the cutout portion 2c. Then, as shown in FIG. 13, the flanges 1c and the buckling portions 1f of the rivet 1 sandwich and fasten the members 3 and 4 in a mutually pressed state. On the other hand, FIG. 14 uses a fastener composed of the rivet 1 and the mandrel 2 described above to fasten a thick member 6 such as a heat sink and a plate-shaped member 7 such as a printed wiring board to each other. It shows the state of being done. In this example, blind holes 8 are formed in the members 6 and 7, and the main body portion 1 a of the rivet 1 is inserted into the blind holes 8.

In order to fasten the members 6 and 7, first, the rivet 1 into which the mandrel 2 is inserted is attached to the head 2 of the mandrel 2.
It is inserted into the blind hole 8 from the a side. Next, by pulling the shaft portion 2b of the mandrel 2 while pressing the flange 1c of the rivet 1, the head portion 2a of the mandrel 2 presses the open end 1d of the rivet 1. By this pressing, the main body portion 1a of the rivet 1 is plastically deformed, and the blind hole 8 and the shaft portion 2b of the mandrel 2 are pressed in the cross sectional direction. At this time, since the main body portion 1a is located inside the blind hole 8, a buckling portion larger than the inner diameter of the blind hole 8 as shown in FIG. 13 is not formed.

Further, by pulling the mandrel 2, the shaft portion 2b of the mandrel 2 is broken from the cutout portion 2c. Then, as shown in FIG. 14, the members 6 and 7 are fastened to each other by the pressing force of the main body portion 1a of the rivet 1 in the cross-sectional direction.

[0009]

However, the fastener composed of the rivet 1 and the mandrel 2 is inserted into the blind hole 8 formed in the members 6 and 7 so that the members 6 and 7 are mutually connected. When fastening, the members 6 and 7 are fastened only by the frictional force between the outer surface of the body 1a and the inner surface of the blind hole 8 which is generated by the pressing force of the body 1a in the cross-sectional direction. The power was insufficient. Therefore, the fastening force of the members 6 and 7 may decrease due to long-term use or vibration.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a fastener capable of securely fastening a plurality of members by utilizing blind holes.

[0011]

A fastener according to claim 1 comprises a tubular rivet, a head portion for pressing an open end of the rivet, and a shaft portion extending from the head portion and inserted into the rivet. In a fastener with a mandrel having, inserted into the shaft of the mandrel, disposed between the head of the mandrel and the open end of the rivet,
The washer includes a washer that is inclined outward from the head side toward the opening end side, and the washer is flattened by being crushed in the axial direction of the mandrel when the head presses the opening end.
It is characterized in that an expanded portion that protrudes from the outer periphery of the rivet by being deformed into a shape is provided.

A fastener according to a second aspect is the fastener according to the first aspect, wherein the mandrel is provided with a recess on the surface of the shaft portion inserted into the rivet. The fastener according to claim 3 is the fastener according to claim 2, wherein the rivet induces plastic deformation of the rivet at a position close to the concave portion of the mandrel when the mandrel is inserted into the rivet. It is characterized in that it is provided with a guide recess.

A fastener according to a fourth aspect is the fastener according to any one of the first to third aspects, wherein the mandrel has an inner peripheral side of the washer on the head side of the shaft portion. It is characterized in that a notch portion that fits into the mandrel is provided.

A fastener according to a fifth aspect is the fastener according to any one of the first to fourth aspects, wherein the washer has a slit for expanding the washer in a cross sectional direction from an inner periphery to an outer periphery. The mandrel is characterized in that a taper portion whose diameter increases toward the head portion is provided on the head portion side of the shaft portion.

(Operation) In the fastener according to the first aspect, the mandrel having the washer inserted in the shaft portion is inserted into the rivet from the shaft portion side. In this state, rivets are inserted from the head side of the mandrel into blind holes formed in a plurality of members for fastening.

After that, by pulling the mandrel shaft while pressing the rivet, the head presses the open end of the rivet through the washer. By this pressing, the rivet
It plastically deforms in the blind hole and presses the inner wall of the blind hole and the mandrel. That is, the rivet, blind hole, and mandrel are fixed to each other by frictional force.

After the plastic deformation of the rivet reaches the limit, the washer starts to be deformed by being pressed by the head of the mandrel. When the washer becomes flat, the expanded portion provided on the washer projects from the outer periphery of the rivet and cuts into the inner wall of the blind hole. As a result, in addition to fixation by frictional force due to plastic deformation of the rivet, a plurality of members, mandrels,
The rivets are firmly integrated and a plurality of members are securely fastened.

In the fastener according to the second aspect, since the mandrel shaft portion inserted into the rivet is provided with the recessed portion, when the mandrel shaft portion is pulled, a part of the plastically deformed rivet is recessed. It bites into and the rivet and mandrel are integrated. Therefore, the mandrel is prevented from moving in the axial direction in the blind hole. And by the head of the mandrel and the open end of the rivet,
The washer is securely clamped.

In the fastener according to the third aspect of the present invention, since the rivet is provided with the guide recess for guiding the buckling, when the shaft of the mandrel is pulled, the pressing force applied to the rivet is concentrated in the guide recess, and the plasticity of the rivet is increased. Deformation starts from this guiding recess. Therefore, the rivet can be easily plastically deformed even if the tensile force of the mandrel shaft is small. Further, since the guide recess is close to the recess of the mandrel, a part of the plastically deformed rivet can be directly inserted into the recess of the mandrel.

In the fastener according to claim 4, since the notch for fitting the inner peripheral side of the washer into the mandrel is provided on the head side of the mandrel shaft, the mandrel and the washer can be handled integrally. The number of parts can be reduced, and the parts can be easily handled. Further, since it is not necessary to insert the washer into the mandrel during the fastening work, the time required for the fastening work is reduced.

In the fastener of claim 5, the washer is provided with slits from the inner circumference to the outer circumference, and the shaft portion of the mandrel is provided with:
Since the taper part that increases in diameter toward the head is provided, when the mandrel shaft is pulled, the taper part presses the inner circumference of the washer from the center side to widen the slit and direct the washer to the outside. To expand. For this reason, the washer is sufficiently projected from the outer circumference of the rivet, and it is possible to more reliably dig into the inner circumference of the blind hole.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a first fastener of the present invention.
The embodiment (corresponding to claim 1 to claim 4) is shown. The fastener of the present invention comprises a rivet 21, a mandrel 23 and a washer 25.

The rivet 21 is made of a metal material such as aluminum which is prone to plastic deformation, and has a cylindrical main body 21a and a flange 21c formed at one end 21b of the main body 21a. Body 21a
An induction recess 21d having an arcuate cross-section is formed in an annular shape along the cross-section at substantially the center of the outer circumference of the shaft in the axial direction.

The mandrel 23 is made of steel or the like having a higher rigidity than the rivet 21. Mandrel 2
Reference numeral 3 denotes a head portion 23b having a flat surface 23a that abuts an opening end 21e of the rivet 21 opposite to the flange 21c.
And a shaft portion 23 extending from the flat surface 23a of the head portion 23b at a right angle and inserted into the through hole 21f of the rivet 21.
and c.

The outer diameter D1 of the head portion 23b is smaller than the outer diameter D2 of the main body portion 21a of the rivet 21. Shaft 2
The outer diameter D3 of 3c is substantially the same as the inner diameter D4 of the through hole 21f of the rivet 21, and the mandrel 23
The shaft portion 23c can be slidably inserted into the through hole 21f of the rivet 21. Mandrel 23 shaft 23
In c, a notch 23d having a triangular cross section is formed in an annular shape along the cross section at approximately the center in the longitudinal direction. The notch portion 23d is formed so as to be broken when the shaft portion 23c of the mandrel 23 is pulled with a predetermined force. The cutout portion 23d is formed in the through hole 2 when the shaft portion 23c of the mandrel 23 is inserted into the through hole 21f of the rivet 21.
It is formed so as to be located within 1f.

On the surface of the shaft portion 23c of the mandrel 23,
A recess 2 having an arc-shaped cross section is provided on the head 23b side from the notch 23d
3e is formed annularly along the cross section. In this concave portion 23e, the mandrel 23 is inserted into the rivet 21, and the flat surface 23a of the head portion 23b has the open end 21e of the rivet 21.
It is formed so that the position in the axial direction is substantially the same as that of the guide recess 21d in the state of contacting with. Also, the recess 23
The reason that e is formed to have an arcuate cross section is to prevent the recess 23e from breaking due to stress concentration in the recess 23e when the shaft 23c of the mandrel 23 is pulled.

The head portion 2 is attached to the shaft portion 23c of the mandrel 23.
A cut portion 23 having a diameter smaller than that of the shaft portion 23c at the end on the 3b side.
f is formed. The width of the cut portion 23f in the axial direction is
It is made thicker than the wall thickness of the washer 25. A washer 25 is provided in the notch 23f of the mandrel 23. The washer 25 is made of steel or the like having a spring property, and as shown in FIG. 2, has a circular shape having a through hole 25a in the center.

Further, as shown in FIG. 3, the washer 25 includes the head 23b of the mandrel 23 and the open end 2 of the rivet 21.
It is formed so as to be straight and inclined outward toward 1e.
The inner diameter D5 of the through hole 25a of the washer 25 is larger than the outer diameter D6 of the notch 23f of the mandrel 23, and the shaft 2
It is smaller than the outer diameter D7 of 3c. That is, the inner periphery 25b side of the washer 25 is fitted into the cut portion 23f, and this state is maintained without coming off from the cut portion 23f.

The outside diameter D8 of the washer 25 is smaller than the outside diameter D2 of the main body portion 21a of the rivet 21 when the washer 25 is inclined. Also, as shown in FIG.
The outer diameter D8 of the washer 25 is larger than the outer diameter D2 of the main body portion 21a of the rivet 21 when the is was pressed from the flat surface side into a flat shape. That is, the washer 25 has the expansion portion 25d that projects from the outer periphery of the main body portion 21 when it is made flat.

In the fastener described above, a plurality of members are fastened to each other as shown below. In this embodiment, an example in which a heat sink made of aluminum or the like is fastened to a printed wiring board will be described. That is, first, as shown in FIG. 5, the blind hole 31 is formed by aligning the hole 29a of the heat sink 29 with the through hole 27a of the printed wiring board 27. The inner diameter of the blind hole 31 is sized so that the main body portion 21a of the rivet 21 is slidably inserted. Then, the rivet 21 into which the mandrel 23 with the washer 25 is inserted is inserted into the blind hole 31 from the head 23 b side of the mandrel 23. Here, since the washer 25 is fitted into the cut portion 23f of the mandrel 23 in advance,
The number of parts is reduced and the parts are easily handled.
Further, it is not necessary to insert the washer 25 into the mandrel 23 at the time of fastening work, and the working time of fastening work is reduced.

Next, by pulling the shaft portion 23c of the mandrel 23 while pressing the flange 21c of the rivet 21, the head portion 23b of the mandrel 23 presses the open end 21e of the rivet 21 via the washer 25. In addition,
The washer 25 has such strength that it does not become flat when pressed.
It is formed by selecting the material, plate thickness and slit width, and applying heat treatment, etc.

Opening end 2 of rivet 21 by head 23b
By pressing 1e, as shown in FIG. 6, the main body portion 21a of the rivet 21 starts plastic deformation. At this time, the guide recess 2
Since the stress is most likely to be concentrated on 1d, the guide recess 21d first buckles. Due to this buckling, the guide recess 21d
The periphery of is plastically deformed, and a part of the main body 21a bites into the recess 23e of the mandrel 23. Where the rivet 21
Since the guide recess 21d is formed in the main body 21a of the, the plastic deformation of the main body 21a easily occurs, and the mandrel 2
The force for pulling the shaft portion 23c of No. 3 is minimal.

At the same time, the main body portion 21a of the rivet 21 is
The blind hole 31 and the shaft portion 23c of the mandrel 23 are pressed in the cross-sectional direction. Further, by pulling the mandrel 23, the main body portion 21a of the rivet 21 is plastically deformed to the limit, and as shown in FIG. 7, the washer 25 is pressed by the head portion 23b and deformed into a flat shape. Due to this deformation, the expanded portion 25d of the washer 25 bites into the inner wall of the blind hole 31. By this bite, the heat sink 29, the printed wiring board 27, the mandrel 23, and the rivet 21 are integrated via the washer 25, and the heat sink 29 and the printed wiring board 27 are securely fastened.

Thereafter, by pulling the shaft portion 23c of the mandrel 23 further, as shown in FIG.
The front end side of c is broken from the cutout portion 23d. Then, the work of fastening the heat sink 29 and the printed wiring board 27 is completed. In the fastener configured as described above, the rivet 2 is inserted into the notch 23f of the mandrel 23 from the head 23b side.
Since the washer 25 that is inclined outward toward the open end 21e side of 1 is fitted, when the shaft portion 23c of the mandrel 23 is pulled, the head portion 23b presses the washer 25, and the washer 25 deforms to form a flat shape. And the extension 25d of the washer 25 becomes
Can be projected from the outer periphery of the main body portion 21a of the rivet 21.

Therefore, when the heat sink 29 is fastened to the printed wiring board 27 by using the blind hole 31,
The washer 25 repels the inner wall of the blind hole 31 and bites depending on the material, so that the rivet 21 is fixed by the frictional force due to plastic deformation, and the printed wiring board 2 is also inserted through the washer 25.
7, heat sink 29, mandrel 23, rivet 21
Can be firmly integrated, and the heat sink 29 can be securely fastened to the printed wiring board 27.

Further, a recess 23 having an arcuate cross section is formed on the surface of the shaft portion 23c of the mandrel 23 inserted into the rivet 21.
Since the e is formed in an annular shape along the cross section, the mandrel 2
By pulling part of the plastically deformed rivet 21 into the recess 23e when the shaft portion 23c of No. 3 is pulled, the rivet 21 and the mandrel 23 can be integrated. Therefore, the mandrel 23 can be prevented from moving in the axial direction in the blind hole 31, and the washer 25 can be reliably clamped by the head 23b of the mandrel 23 and the opening end 21e of the rivet 21. .

Further, since the recess 23e is formed in an arcuate cross section, stress concentration is unlikely to occur in the recess 23e when the shaft 23c of the mandrel 23 is pulled, and the recess 23e can be prevented from breaking. Since the guide recess 21d having an arcuate cross section is formed in an annular shape along the cross section on the outer periphery of the main body 21a of the rivet 21, the rivet 21 is pulled when the shaft 23c of the mandrel 23 is pulled.
The pressing force applied to the rivet 21 can be concentrated in the guide recess 21d, and the plastic deformation of the rivet 21 can be started from the guide recess 21d. Therefore, even if the pulling force of the shaft portion 23c of the mandrel 23 is small, the rivet 21 can be easily plastically deformed.

Further, since the guide recess 21d is provided at a position close to the recess 23e of the mandrel 23, a part of the plastically deformed rivet 21 is left as it is in the recess 2 of the mandrel 23.
It is possible to get into 3e. Further, on the side of the head 23b of the shaft portion 23c of the mandrel 23, the inner circumference 2 of the washer 25 is
Notch 23f for fitting the 5b side into the mandrel 23
Since the above is provided, the mandrel 23 and the washer 25 can be integrally handled. Therefore, the number of parts can be reduced and the parts can be easily handled.

Further, since it is not necessary to insert the washer 25 into the mandrel 23 during the fastening work, the time required for the fastening work can be reduced. FIG. 9 shows a second embodiment (corresponding to claim 5) of the fastener of the present invention.
In this embodiment, the shape of the shaft 33a of the mandrel 33 on the head portion 33b side and the shape of the washer 35 are different from the shapes of the mandrel 23 and the washer 25 of the first embodiment. The same rivet 21 as in the first embodiment is used.

The head 33b of the mandrel 33 and the notch 33
The c and the concave portion 33d are formed in the same shape at the same positions as the head portion 23b, the cutout portion 23d, and the concave portion 23e of the first embodiment. The head portion 3 is attached to the shaft portion 33a of the mandrel 33.
At the end on the 3b side, a cut portion 33 having a diameter smaller than that of the shaft portion 33a.
e is formed. The width of the notch 33e in the axial direction is
It is made thicker than the wall thickness of the washer 35. A washer 35 is arranged in the cut portion 33e.

On the head 33b side of the notch 33e, the head 3
A taper portion 33f having a larger diameter toward 3b is formed. The outer diameter of the tapered portion 33f on the notch 33e side is the same as the outer diameter of the notch. The outer diameter of the tapered portion 33f on the head 33b side is larger than the inner diameter of the washer 35, and
It is smaller than the outer diameter of the shaft portion 33a. The washer 35
The washer 25 of the first embodiment is formed to have almost the same outer shape.

As shown in FIG. 10, the washer 35 is formed with a slit 35c extending in the radial direction from the inner circumference 35a to the outer circumference 35b. With this slit 35c, the washer 35 can be expanded and deformed in the cross-sectional direction. In the fastener described above, as shown in FIG. 9, when the shaft portion 33b of the mandrel 33 is pulled and the washer 35 is deformed into a flat shape, the inner circumference 35a of the washer 35 is centered by the tapered portion 33f of the shaft portion 33b. Pressed from the side. By this pressing, the washer 35 becomes flat while expanding and deforming toward the outer periphery 35b. Therefore, the outer circumference 35b of the washer 35 is
Sufficiently protrude from the outer periphery of the main body portion 21a of the rivet 21.

The fastener of this embodiment can also obtain the same effects as those of the first embodiment described above,
In this embodiment, since the slit 35c is formed in the washer 35 and the taper portion 33f is formed on the head portion 33b side of the shaft portion 33a of the mandrel 33, the shaft portion 3 of the mandrel 33 is formed.
When pulling 3a, the inner circumference 33a of the washer 35 can be pressed from the center side by the taper portion 33f.
Can be flattened while being expanded and deformed toward the outside. Therefore, by projecting the outer circumference 35b of the washer 35 onto the outer circumference of the main body portion 21a of the rivet 21, it is possible to sufficiently dig into the inner wall of the blind hole, and more reliably a member such as a heat sink can be provided on the printed wiring board or the like. Can be concluded.

In the above-described first embodiment, the example in which the washer 25 is formed by inclining straightly outward from the head 23b of the mandrel 23 toward the open end 21e of the rivet 21 has been described. The present invention is not limited to such an embodiment, and for example, as shown in FIG. 11, a washer 37 inclined in a curved shape may be formed. In this case, when the washer 37 is flat, The outer circumference of 37 can be more sufficiently projected from the outer circumference of the main body portion 21 a of the rivet 21.

Further, in the above-described first embodiment, an example in which the expanded portion 25d of the washer 25 is digged into the inner wall of the blind hole 31 has been described, but the present invention is not limited to this embodiment. Instead of the blind hole 31, the inner wall of the through hole may be cut into. Then, in the above-described first embodiment, an example in which the washer 25 is formed in a circular shape has been described, but the present invention is not limited to this embodiment, and for example, an oval-shaped washer when flat, It may be formed by bending the longitudinal direction side. In this case, when the washer is deformed into a flat shape, the end portion in the longitudinal direction is formed into the main body portion 21.
It can be sufficiently projected from the outer periphery of a.

Further, in the above-described first embodiment, an example in which the washer 25 is formed in a circular shape has been described, but the present invention is not limited to this embodiment, and for example, the outer periphery of the washer 25 may be It may be formed in a tooth shape by cutting out at intervals. Further, in the above-described first embodiment, an example in which the recess 23e of the mandrel 23 is formed in an annular shape along the cross section and a band-shaped recess is formed along the outer periphery of the mandrel 23 is described. However, the concave portion having a circular cross section may be formed at a plurality of positions. In this case, the shaft portion 2 of the mandrel 23 is not limited to the above.
When pulling 3c, it is possible to reliably prevent breakage of the recess.

[0047]

According to the fastener of claim 1, the washer is provided between the head of the mandrel and the open end of the rivet and is inclined outward from the head side toward the open end side. In addition, when the head is pressed against the open end, the expansion part that protrudes from the outer periphery of the rivet is provided, so by pulling the mandrel shaft, the head presses the washer, and the washer deforms and becomes flat. Thus, the expanded portion of the washer can be projected from the outer circumference of the rivet.

Therefore, when a plurality of members are fastened by using the blind holes of these members, the washer bites into the inner wall of the blind hole, so that the plurality of members, the mandrel, and the rivet are firmly fixed through the washer. Can be integrated with each other, and a plurality of members can be securely fastened. In the fastener according to claim 2, since the recess is provided on the surface of the shaft of the mandrel to be inserted into the rivet, when the shaft of the mandrel is pulled, a part of the plastically deformed rivet bites into this recess. As a result, the rivet and the mandrel can be integrated. Therefore, the mandrel can be prevented from moving in the axial direction in the blind hole, and the washer can be reliably clamped by the head of the mandrel and the open end of the rivet.

In the fastener according to the third aspect, since the rivet is provided with the guide recess for guiding the buckling, when the mandrel shaft is pulled, the pressing force applied to the rivet is concentrated in the guide recess, and the rivet plasticity is increased. Deformation can take place from this guiding recess. Therefore, even if the pulling force of the mandrel shaft is small, the rivet can be easily plastically deformed.

Further, since the guide recess is provided at a position close to the recess of the mandrel, a part of the plastically deformed rivet can be directly inserted into the recess of the mandrel. In the fastener according to the fourth aspect, since the notch portion for fitting the inner peripheral side of the washer into the mandrel is provided on the head side of the shaft portion of the mandrel, the mandrel and the washer can be handled integrally. Therefore, the number of parts can be reduced and the parts can be easily handled.

Further, since it is not necessary to insert the washer into the mandrel during the fastening work, the time required for the fastening work can be reduced. In the fastener according to claim 5, the washer is provided with a slit from the inner circumference to the outer circumference, and the shaft portion of the mandrel is provided with the taper portion whose diameter increases toward the head. Therefore, when the shaft portion of the mandrel is pulled. The taper portion presses the inner circumference of the washer from the center side to widen the slit, and the washer can be expanded outward. Therefore, the washer can be sufficiently projected from the outer periphery of the rivet,
It is possible to more reliably dig into the inner circumference of the blind hole.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a fastener of the present invention.

FIG. 2 is a top view showing details of a washer.

FIG. 3 is a sectional view showing details of a washer.

FIG. 4 is an explanatory view showing a state in which the washer has a flat shape.

FIG. 5 is a cross-sectional view showing a state in which a rivet is inserted into a blind hole for fastening a heat sink to a printed wiring board.

FIG. 6 is a cross-sectional view showing a state in which the rivet is buckled from the guide recess by pulling the mandrel.

FIG. 7 is a cross-sectional view showing a state in which the expanded portion of the washer bites into the inner wall of the blind hole.

FIG. 8 is a cross-sectional view showing a state in which the shaft portion of the mandrel is broken from the cut portion.

FIG. 9 is a sectional view showing a second embodiment of the fastener of the present invention.

FIG. 10 is a top view showing details of a washer.

FIG. 11 is a side view showing an example in which the washer is inclined into a curved shape.

FIG. 12 is a cross-sectional view showing a conventional fastener.

FIG. 13 is a cross-sectional view showing a state in which two members are fastened using a conventional fastener.

FIG. 14 is a cross-sectional view showing a state in which two members are fastened by inserting a conventional fastener into a blind hole.

[Explanation of symbols]

21 rivets 21a main body 21b One end 21c flange 21d Guide recess 21e Open end 21f through hole 23 Mandrel 23a flat surface 23b head 23c Shaft 23d notch 23e recess 23f notch 25 washers 25a through hole 25b inner circumference 27 Printed wiring board 27a through hole 29 heat sink 29a hole 31 blind hole 33 Mandrel 33a Shaft 33b head 33c Notch 33d recess 33e Notch 33f taper part 35 washer 35a inner circumference 35b outer circumference 35c slit 37 washer D1 outer diameter D2 outer diameter D3 outer diameter D4 inner diameter D5 inner diameter D6 outer diameter D7 outer diameter D8 outer diameter

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16B 19/10 F16B 13/04

Claims (5)

(57) [Claims] 1. A fastener comprising: a tubular rivet; a mandrel having a head that presses the open end of the rivet; and a mandrel that extends from the head and is inserted into the rivet. A washer that is inserted into the shaft portion of the mandrel, is disposed between the head portion of the mandrel and the opening end of the rivet, and is inclined outward from the head side toward the opening end side. Included, the washer, when pressed to the open end by the head,
The washer is crushed in the axial direction of the mandrel to form a flat shape.
A fastener which is provided with an expanded portion that projects from the outer periphery of the rivet by being deformed . 2. The fastener according to claim 1, wherein the mandrel has a recess on the surface of the shaft portion inserted into the rivet. 3. The fastener according to claim 2, wherein the rivet is a guide recess that guides plastic deformation of the rivet at a position close to the recess of the mandrel when the mandrel is inserted into the rivet. A fastener characterized by being provided with. 4. The fastener according to any one of claims 1 to 3, wherein the mandrel has a cutout for fitting the inner peripheral side of the washer into the mandrel on the head side of the shaft portion. A fastener characterized by having an insert portion. 5. The fastener according to any one of claims 1 to 4, wherein the washer is provided with a slit that expands the washer in a cross-sectional direction from an inner circumference to an outer circumference, and the mandrel includes: A fastener characterized in that a taper portion whose diameter increases toward the head is provided on the head side of the shaft.