JPH10306814A - Blind rivet, mandrel therefor, and blind rivet structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mandrel for a blind rivet to prevent the occurrence of crawling of a head part and perform stable buckling without processing to increase the strength of the tip part of an annular body. SOLUTION: In the mandrel 1 of a blind rivet to effect insertion in an annular body 2 and plastic deformation of the annular body 2, the mandrel 1 comprises a head part 1f brought into contact with one end part of the annular body 2; and a stem part 1a inserted in the annular body 2. In the head part 1f, the angle of a surface, making contact with the annular body 2, with the stem of the mandrel 1 is an acute angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blind rivet that can be operated from one side, a mandrel thereof and a blind rivet structure, and more particularly to a blind rivet suitable for fastening a copying machine or the like, a mandrel thereof and a blind rivet structure. .

[0002]

2. Description of the Related Art As shown in FIG. 13, as a structure of a copying machine, a scanner unit (reading portion) 51, a main body unit (a portion containing a photosensitive member, etc.) 52, And a paper unit 53. Conventionally, in order to increase the production efficiency at the mass production stage, the rivet 54 is used only for the scanner unit 51 to which a small load is applied.

[0003] The rivet 54 is formed, for example, by folding the side surfaces of the rivet 54 with sheet metal and making holes to stop them. In such fastening, a blind rivet that can be fastened from one side is used. This blind rivet 54
As shown in FIG. 15, an annular body 55 that is plastically deformed and a mandrel 56 that plastically deforms the body 55 are provided.

[0004] The body 55 has a flange portion 55a at one end of a cylindrical portion having the same diameter through which the mandrel 56 is inserted, and which comes into contact with a member to be fastened. The mandrel 56 has, at its tip, a head portion 56a for buckling a cylindrical portion of the body 55 and a columnar portion 56b of the same diameter protruding rearward of the head portion 56a. The formed break portion 56c is provided. The back surface of the head section is orthogonal to the axis of the mandrel. Therefore, only a force parallel to the axis of the mandrel acts between the head portion and the tip of the annular body.

[0005] Using such a blind rivet,
In order to fasten the first member and the second member, which are the members to be fastened, first, as shown in FIG. 14A, a rivet is attached to the rivet, and the holes of the first member and the second member which are the joining portions are formed. Plug in. Next, as shown in FIG.
Grasp the handle (not shown) of the riveter and pull the mandrel in the direction α (see FIG. 15) to buckle the body.
Next, as shown in FIG. 14 (C), the mandrel is further pulled to break from the break portion, thereby completing the fastening.

Normally, when fastening a sheet metal with a blind rivet, the diameter of the hole through which the blind rivet is inserted is made sufficiently larger than the outer diameter of the portion through which the blind rivet is inserted, so that a margin is provided. The reason is that it is easy to insert rivets, the cost increases when the dimensional accuracy is increased, and the need for a jig for suppressing warpage when the hole diameter is small has to be avoided.

[0007]

However, when the above blind rivet is fastened, as shown in FIG. 16, the head of the mandrel may go into the hole of the annular body and the annular body may not buckle. was there. Therefore, as shown in FIG. 15, it was necessary to perform processing to increase the strength of the distal end portion of the annular body.

Accordingly, the present invention is directed to a blind rivet capable of preventing the head portion from getting into the head portion and performing stable buckling without performing high-strength processing on the distal end portion of the annular body, and its mandrel and blind rivet structure. The purpose is to provide the body.

[0009]

In order to achieve the above object, a blind rivet mandrel according to claim 1 is inserted into an annular body to plastically deform the annular body. In the blind rivet mandrel, the mandrel is: A head portion abutting on one end of the annular body,
A shaft portion connected to the head portion and inserted through the annular body, wherein the head portion has an acute angle between a surface contacting the annular body and a shaft of a mandrel.

The blind rivet mandrel according to claim 2 is inserted into the annular body to plastically deform the annular body. In the blind rivet mandrel, the mandrel is in contact with one end of the annular body. A head portion connected to the head portion and a shaft portion inserted into the annular body, the shaft portion having a large-diameter first body portion connected to the head portion;
A second body formed to be smaller in diameter than the body, and a step provided between the first body and the second body, wherein the head is in contact with the annular body. The angle between the mandrel and the axis is an acute angle.

The blind rivet mandrel according to claim 3 is the blind rivet mandrel according to claim 2, wherein the step portion has a predetermined angle formed between the first body portion and the second body portion. It is characterized in that it is an inclined surface.

According to a fourth aspect of the present invention, there is provided a blind rivet mandrel according to the second aspect, wherein the mandrel is harder than the annular body.

The blind rivet mandrel according to claim 5 is inserted into the annular body to plastically deform the annular body. In the blind rivet mandrel, the mandrel has a shaft portion inserted through the annular body. A head portion connected to one end of the shaft portion, wherein the shaft portion has a first effective length for fastening the member to be fastened in order from the head portion side.
A torso portion, a bulging portion for expanding the outer diameter of the annular body, and a second torso portion connected to the bulging portion via a step portion and held to plastically deform the annular body. The head portion is characterized in that an angle between a surface that contacts the annular body and an axis of the mandrel is an acute angle.

According to a sixth aspect of the present invention, there is provided a blind rivet mandrel according to the second or fifth aspect, wherein the shaft portion has a break portion which is broken after fastening. I have.

According to a seventh aspect of the present invention, there is provided a blind rivet mandrel according to the sixth aspect, wherein the break portion is continuous with the step portion.

The blind rivet mandrel according to claim 8 is characterized in that, in the blind rivet mandrel according to claim 6 or 7, the broken portion is a V-groove.

According to a ninth aspect of the present invention, there is provided a mandrel of a blind rivet according to the sixth aspect, wherein the break portion is disposed on the opposite side of the step portion with respect to the head portion. And

A blind rivet mandrel according to a tenth aspect of the present invention is the blind rivet mandrel according to any one of the sixth to ninth aspects, wherein the diameter of the broken portion is the minimum diameter of the entire mandrel. .

[0020] The mandrel of the blind rivet according to claim 11 is the mandrel of the blind rivet according to claim 2 or 5, wherein the cross-sectional area of the first body is obtained by removing the cross-sectional area of the second body. Is characterized by being equal to or larger than an annular area obtained by subtracting a sectional area of an outer shape of the annular body from a sectional area of a hole of a member to be fastened into which the annular body is inserted. I do.

A blind rivet mandrel according to a twelfth aspect of the present invention is a blind rivet mandrel that is inserted into an annular body to plastically deform the annular body, wherein the mandrel has a head portion that contacts one end of the annular body. And a tapered conical portion connected to the head portion, wherein the head portion has an acute angle between a surface contacting the annular body and a shaft of the mandrel.

A blind rivet according to a thirteenth aspect of the present invention is a blind rivet which is inserted and fastened to a member to be fastened from one side. The head portion of the mandrel is characterized in that the head portion of the mandrel has an acute angle between the surface that contacts the annular body and the axis of the mandrel.

A blind rivet according to a fourteenth aspect of the present invention is a blind rivet comprising: an annular body inserted through a member to be fastened; and a mandrel inserted through the annular body to plastically deform the annular body. A head portion abutting on one end of the annular body, and a shaft portion connected to the head portion and inserted into the annular body, wherein the shaft portion is connected to the head portion. A first body portion having a diameter, a second body portion formed smaller in diameter than the first body portion, and a step portion provided between the first body portion and the second body portion; The annular body includes a large-diameter first hole, a second hole smaller in diameter than the first hole, and a second hole connected to the first hole via a step, and an end of the second hole. The head portion abuts on the annular body. It is characterized in that the angle between the axis of that surface and the mandrel is an acute angle.

A blind rivet according to a fifteenth aspect of the present invention is a blind rivet comprising: an annular body inserted through a member to be fastened; and a mandrel inserted through the annular body to plastically deform the annular body. Is effective when the effective volume of the second annular body constituting the second hole is larger than the volume of the gap between the hole of the object to be fastened and the outer periphery of the annular body. A groove portion having an absorbing portion for absorbing a portion whose volume protrudes from the gap, and having a size that is filled with the expanded diameter of the annular body at least to an end of the gap formed by the member to be fastened and the annular body; Wherein the head section has an acute angle between a surface that contacts the annular body and an axis of the mandrel.

A blind rivet according to a sixteenth aspect of the present invention is a blind rivet comprising: an annular body inserted into a member to be fastened; and a mandrel inserted through the annular body to plastically deform the annular body. A head portion abutting on one end of the annular body, and a shaft portion connected to the head portion and inserted into the annular body, wherein the shaft portion is connected to the head portion. A first body having a diameter, a second body formed smaller in diameter than the first body, and a step provided between the first body and the second body. The portion is an inclined surface having a predetermined angle formed between the first body portion and the second body portion, and the annular body has a large-diameter first hole portion and a step formed in the first hole portion. A second hole having a smaller diameter than the first hole, continuous through the portion; A flange portion provided at an end of the two-hole portion, wherein the step portion is an inclined surface, and the inclined surface of the mandrel is formed more gently than the inclined surface of the annular body; Is characterized in that the angle between the surface in contact with the annular body and the axis of the mandrel is an acute angle.

A blind rivet according to a seventeenth aspect of the present invention is the blind rivet according to any one of the thirteenth to sixteenth aspects, wherein a small diameter portion having a diameter smaller than the tip diameter of the shaft portion is provided between the head portion and the shaft portion of the mandrel. It is characterized by having.

A blind rivet structure according to claim 18 is a blind rivet structure comprising: an annular body inserted into a member to be fastened; and a mandrel inserted through the annular body to plastically deform the annular body. At
The annular body is filled with the expanded diameter of the annular body up to an end of a gap formed by the member to be fastened and the annular body, and the head portion is formed between a surface abutting on the annular body and a shaft of a mandrel. The angle formed is an acute angle.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. In addition, in order to avoid redundant and complicated description, the same configuration and similar configuration are denoted by common reference numerals, and description thereof will be omitted.

FIG. 1A is a sectional view of a blind rivet according to an embodiment of the present invention, FIG. 1B is a sectional view of a mandrel according to another embodiment of the present invention, and FIG. It is sectional drawing of the mandrel which concerns on embodiment. As shown in FIG. 1A, the blind rivet includes an annular body 2 that is plastically deformed and a mandrel 1 that plastically deforms the annular body 2.

The annular body 2 has a member to be fastened to the base end of the second annular body 2g through which the mandrel 1 is inserted (the first member in FIG. 2).
In addition to the flange portion 2h abutting on the member 3 and the second member 4), the inner diameter of the annular body 2 is provided with an annular stepped portion 2d as an expanding means. That is, a large-diameter hole portion 2b as a first hole portion is formed in the first annular body portion 2f near the front end, and the second hole of the second annular body portion 2g is formed in the large-diameter hole portion 2b via a step 2d. The small-diameter hole portion 2c which is a portion is continuous, and a through-hole is formed by the large-diameter hole portion 2b, the step portion 2d, and the small-diameter hole portion 2c. On the base end side of the small-diameter hole portion 2c, an annular groove portion 2i, which is an absorbing portion that absorbs a portion where the effective volume due to the swelling protrudes from the gap S (see FIG. 16), is provided.
Outer circumference of the annular body 2 corresponding to the above, that is, the second annular body 2g
Are formed continuously. The annular groove 2i has a size enough to be filled by the expanded diameter of the annular body 2 up to the end of the gap S formed by the member to be fastened and the annular body 2. The step portion 2d is an inclined surface having a predetermined angle, that is, 45 degrees with respect to the axis of the mandrel 1 in this embodiment.

The mandrel 1 has a head part 1f abutting on one end of the annular body 2 and a shaft part 1a connected to the head part 1f and inserted through the annular body 2. The shaft portion 1a has a large-diameter first body portion 1b connected to the head portion 1f, a second body portion 1c formed smaller in diameter than the first body portion 1b, a first body portion 1b, and a second body portion 1b. Body 1c
And a step portion 1d provided between them. The step portion 1d is formed on an inclined surface with respect to the pulling direction α of the mandrel 1. Also, the step portion 2 of the annular body 2
d is also formed on the inclined surface with respect to the pulling direction α of the mandrel 1 similarly to the mandrel 1.

The rear surface 1r of the head 1f has an acute angle between the surface of the mandrel 1 and the surface of the mandrel 1 which is in contact with the annular body 2. Therefore, the axial center extends from the rear surface 1r of the head 1f to the distal end of the annular body 2. Is applied to the head portion 1f.
Does not slip into the annular body 1 and a desired buckling can be obtained. Therefore, stable fastening can be performed without performing high-strength processing. Further, since the distal end portion of the annular body 2 is urged in the axial direction, the mandrel 1 is swaged to the annular body 2 and the mandrel 1 is tightened after the fastening.
Will not fall off.

FIG. 1B shows an embodiment of a mandrel having no step. In this embodiment, the illustration of the annular body is omitted, but the same one as the annular body of FIG. 15 can be used. Note that, as shown in FIG. 1C, the rear surface of the head portion may have an arc-shaped cross section. In this case, the angle between the tangent of the arc-shaped cross section and the axis of the mandrel at the contact portion between the arc-shaped cross section and the annular body becomes an acute angle. As described above, the rear surface of the head portion may be another curve if the tangent line at the contact portion is an acute angle.

The mandrel 1 has a break 1e, which is the minimum diameter of the mandrel 1, continuous with the step 1d.
It is arranged on the opposite side of the head 1f with respect to d. In this embodiment, the break portion 1e is formed in the V-groove so as to be continuous with the step portion 1d. The break portion 1e may be a U-groove or the like other than the V-groove, but the break position can be accurately set by using the V-groove. The step portion 1d has a predetermined angle, which is 4 degrees with respect to the axis of the mandrel 1 in this embodiment.
It is a 5-degree slope.

The first body 1b has an effective fastening length Y corresponding to the thickness of the member to be fastened. In addition, the second
The body 1c is held by a chuck as shown in FIG.
The annular area obtained by subtracting the cross-sectional area of the second body 1c from the cross-sectional area of the first body 1b is the cross-sectional area of the outer shape of the annular body 2 from the cross-sectional area of the hole 4a of the member to which the annular body 2 is inserted. Are formed to be the same or larger than the annular area excluding.

As shown in FIG. 2A, using such a blind rivet, the first member 3 as a member to be fastened is used.
To fasten the second member 4 and the first member 3, first, the annular body 2 and the mandrel 1 inserted through the annular body 2 are inserted into the holes 3 a and 4 a of the first member 3 and the second member 4, respectively.
2 from the side from which the annular body 2 is pulled out, and then pulls the mandrel 1 in the extracting direction α to buckle the annular body 2 and, as shown in FIG.
d and the step portion 1d of the mandrel 1 are pressed against each other. Thus, an external force f3 is applied from the step 1d of the mandrel 1 to the inside of the step 2d of the annular body 2.

Due to the external force f3, the second annular body 2g corresponding to the holes 3a, 4a of the first member 3 and the second member 4 is formed.
Is expanded, that is, the outer diameter of the second annular body 2g is expanded. And as the amount of pulling out the mandrel 1 increases,
The swelling amount increases, and the gap S between the inner diameter of the holes 3a, 4a of the first member 3 and the second member 4 and the outer diameter of the second annular body 2g decreases.

At this time, at the base end side of the small diameter hole 2c,
Since the annular groove portion 2j is formed as an absorbing portion that absorbs a portion where the effective volume of the expanded diameter protrudes from the gap S,
The second annular body 2g constituting the small-diameter hole 2c is expanded and the effective volume is increased by the holes 3a and 4a of the object to be fastened and the second annular body 2g.
Can be absorbed when it is larger than the volume of the gap S between itself and the outer periphery. Therefore, the swelling amount can be made sufficiently larger than the gap S.

In this manner, the "body buckling step" for buckling the first body portion 1b of the annular body 2 and the "body expanding step" for filling the gap S are completed almost simultaneously. In this end state, the first member 3 and the second member 4 can be fastened between the buckled portion of the annular body 2 and the flange portion 2h, and the outer diameter of the annular body 2 is increased by the enlarged diameter portion of the annular body 2. The diameter and the hole 3a of the first member 3 and the second member 4,
4a is adhered. Next, by further pulling out the mandrel 1, as shown in FIG. 2 (C), the mandrel 1 is broken at the breaking portion 1e which is the minimum diameter of the mandrel 1, and the fastening is completed.

According to the blind rivet of this embodiment, almost no gap S exists between the outer diameter of the second annular body 2g of the annular body 2 and the holes 3a, 4a of the first member 3 and the second member 4. Therefore, the first member 3 and the second member 4 do not move even when subjected to an external force f2 (see FIG. 17) that gives a shear force to the annular body 2. That is, even if there is a margin between the outer diameter of the second annular body 2g of the annular body 2 before the fastening and the holes 3a, 4a, there is no change in the position over time after the fastening. In addition, although the positional change with time can be prevented, the hole diameters of the holes 3a and 4a of the member to be fastened into which the blind rivet is inserted can be made sufficiently large, thereby deteriorating the workability and the assembling property. There is no.

Further, it is not necessary to use a jig for correcting the warpage of the first member 3 and the second member 4 at the time of fastening. In addition, the number of contact portions between the annular body 2 and the member to be fastened is larger than that of the related art, and it is firmly fixed, so that the number of rivet hit points can be reduced.

Further, since the swelling diameter is generated almost uniformly in the radial direction of the annular body 2, the hole 3a of the first member 3 and the hole 4a of the second member 4 are automatically aligned. Hole 3
Even if there is play in a and 4a, the first member 3 and the second member 4 are not shifted and fastened after fastening.

The annular body 2 and the mandrel 1 are
The hardness may be the same, but the mandrel 2 is preferably harder. For example, JIS G 3539 is one of the JIS standards for carbon steel wire for cold heading. Of the two types, the harder one (HRB) is used for the mandrel 1 and the softer one is the annular body 2. Can be used for The hardness of the material can be appropriately selected according to the angle of the inclined surface.

Note that the annular body 2 of the blind rivet shown in FIG. 1 has a high-strength portion 2e at least at the end opposite to the flange portion 2h, which is higher in strength than other portions. Buckling can be stably performed without penetrating into the large-diameter hole portion 2b of the first annular body portion 2f. The high-strength portion 2e can be processed by swaging (hammering forging) or the like.

FIG. 3 is a cross-sectional view of a blind rivet according to another embodiment, in which (A) is an overall view and (B) is an enlarged view of a step portion. In the blind rivet of the embodiment of FIG. 3, the steps 1d and 2d are different from those of the embodiment of FIG. In this embodiment, as shown in FIGS. 3A and 3B, the step portions 1d and 2d are formed in an arc-shaped cross section. By forming the cross section in an arc shape or another curved shape in this manner, the shape of the expanded portion can be changed.

FIG. 4 is a cross-sectional view of a blind rivet according to another embodiment, and (A), (B), and (C) are cross-sectional views of the blind rivet. FIG.
In the blind rivet of the embodiment of FIG.
The difference from the blind rivet of the embodiment is that the step portion 1d of the mandrel 1 is a surface orthogonal to the drawing direction α of the mandrel 1. Thus, even if the step portion 1d of the mandrel 1 is perpendicular to the drawing direction α, the first body portion 1b of the mandrel 1 is thicker than the small-diameter hole portion 2c of the annular body 2, so that the annular body 2 can be expanded. I can do it.

The difference between the blind rivet of the embodiment of FIG. 4B and the blind rivet of the embodiment of FIG. 1 is that the stepped portion 2d of the annular body 2 is perpendicular to the direction α in which the mandrel 1 is pulled out. It is to have done. Even if the step 2d of the annular body 2 is made orthogonal to the pulling direction α in this manner, the first body 1b of the mandrel 1 is thicker than the small-diameter hole 2c of the annular body 2, so that the annular body 2 is expanded. Can be done.

The difference between the blind rivet of the embodiment of FIG. 4C and the blind rivet of the embodiment of FIG. 1 is that both the step 2d of the annular body 2 and the step 1d of the mandrel 1 are pulled out of the mandrel 1. That is, the surface is in a direction orthogonal to α. Thus, even if the step 2d of the annular body 2 and the step 1d of the mandrel 1 are both perpendicular to the pulling direction α, the first body 1b of the mandrel 1 is thicker than the small-diameter hole 2c of the annular body 2. The annular body 2 can be expanded in diameter.

FIG. 5 is a sectional view of a blind rivet according to another embodiment, in which (A), (B), (C),
(D) is a sectional view of each blind rivet.
In the blind rivet of the embodiment of FIG.
The difference from the blind rivet of the embodiment (A) is that
That is, the breaking portion 1e is separated from the mandrel 1 in the pulling direction α without being continuous with the step portion 1d. By separating the broken portion 1e of the mandrel 1 in the pull-out direction α in this manner, the breaking position can be set independently of the step portion 1d.

The difference between the blind rivet of the embodiment of FIG. 5 (B) and the blind rivet of the embodiment of FIG. 4 (A) is that the pulling direction α of the mandrel 1 is changed without connecting the broken portion 1e to the step portion 1d. To have been separated.
By separating the broken portion of the mandrel in the drawing direction α in this way, the breaking position can be set independently of the step portion 1d.

The difference between the blind rivet of the embodiment of FIG. 5C and the blind rivet of the embodiment of FIG. 4B is that the pulling-out direction α of the mandrel 1 does not connect the broken portion 1e to the step portion 1d. To have been separated.
In this manner, the pulling direction α
, The breaking position can be set independently of the step portion 1d.

The difference between the blind rivet of the embodiment of FIG. 5D and the blind rivet of the embodiment of FIG. 4C is that the pulling-out direction α of the mandrel 1 does not connect the broken portion 1e to the step portion 1d. To have been separated.
In this manner, the pulling direction α
, The breaking position can be set independently of the step portion 1d.

FIG. 6 is a sectional view of a blind rivet according to another embodiment, and FIGS. 6A and 6B are sectional views of the blind rivet. The difference between the blind rivet of the embodiment of FIG. 6A and the blind rivet of the embodiment of FIG. 5A is that the small-diameter hole portion 12c and the large-diameter hole portion 12b of the annular body 12 have the same conical shape. To form a through-hole. That is, the annular body 12
Since the holes 12b and 12c are tapered from the flange 12h toward the other end, the through holes of the annular body 12 can be easily formed.

Since the rear surface 11r of the head portion 11f forms an acute angle between the surface that comes into contact with the annular body 12 and the axis of the mandrel 11, the rear surface 11r of the head portion 11f extends axially from the rear surface 11r of the head portion 11f to the distal end of the annular body 12. A heading force acts, and the desired buckling can be obtained without the head portion 11f slipping into the annular body 12. Therefore, stable fastening can be performed without performing high-strength processing. Further, since the distal end portion of the annular body 12 is urged in the axial direction, the mandrel 11 is swaged to the annular body 12, and the mandrel 11 does not fall off after fastening.

The difference between the blind rivet of the embodiment of FIG. 6B and the blind rivet of the embodiment of FIG. 6A is that the small-diameter hole portion 22c and the large-diameter hole portion 22b of the annular body 22 are the same. The through hole is formed in a cylindrical shape having a diameter, and the step portion 21 of the shaft portion 21a of the mandrel 11 is formed.
d and the second body portion 21c have the same conical shape. With this configuration, the annular body 22 and the mandrel 21 can be easily processed.

Since the rear surface 21r of the head portion 21f forms an acute angle between the surface that comes into contact with the annular body 22 and the axis of the mandrel 21, the rear surface 21r of the head portion 21f extends axially from the rear surface 21r of the head portion 21f to the distal end of the annular body 22. A heading force acts, and the desired buckling can be obtained without the head portion 21f slipping into the annular body 22. Therefore, stable fastening can be performed without performing high-strength processing. Further, since the distal end portion of the annular body 22 is urged in the axial direction, the mandrel 21 is swaged to the annular body 22, and the mandrel 21 does not fall off after fastening.

As shown in FIGS. 6A and 6B,
Between the heads 11f, 21f of the mandrels 11, 21 and the shafts 11a, 21a, there are shafts 11a, 2a.
Since the small diameter portions 11k and 21k smaller in diameter than the tip diameter of 1a are formed, the tip portions of the annular bodies 12 and 22 are integrated into the recesses after being fastened.

FIG. 7 is a sectional view of a blind rivet according to another embodiment. 8 is a cross-sectional view showing a state in which the blind rivet of FIG. 7 is inserted into an object to be fastened, FIG. 9 is a cross-sectional view showing a state in which the mandrel is slightly pulled out from the state of FIG. 11 is a cross-sectional view showing a state where the mandrel is further pulled out from the state shown in FIG. 10 and the expansion is completed. FIG. 11 is a cross-sectional view showing a state where the mandrel is further pulled out from the state of FIG.

As shown in FIG. 7, the blind rivet includes an annular body 32 that is plastically deformed and a mandrel 31 that plastically deforms the annular body 32. The annular body 32 has a cylindrical portion 3 through which the mandrel 31 is inserted.
At the base end of 2b, there is provided a flange portion 32h which comes into contact with the member to be fastened, and at the inner diameter of the cylindrical portion 32b, there is provided an annular step portion 32d as an expanding means. That is, a large-diameter hole 32b is formed in the first annular body 32f near the front end, and the second annular body 32 is formed in the large-diameter hole 32b via the step 32d.
g, the small-diameter hole portion 32c is continuous, and a through-hole is formed by the large-diameter hole portion 32b, the step portion 32d, and the small-diameter hole portion 32c. On the base end side of the small-diameter hole portion 32c, there is formed an annular groove portion 32j that is an absorbing portion that absorbs a portion where the effective volume of the expanded diameter protrudes from the gap S.

The mandrel 31 has a head portion 31f abutting on one end of the annular body 32, and a head portion 31f.
Shaft portion 3 which is connected to
1a. The shaft portion 31a has a large diameter first body portion 31b connected to the head portion 31f, and in the present embodiment, a first body portion 31b having substantially the same diameter as the first body portion 31b and connected via a break portion 31e. A third trunk portion 31m, a second trunk portion 31c having a smaller diameter than the first trunk portion 31b, and a step portion 3 provided between the first trunk portion 31b and the second trunk portion 31c.
1d. The step portion 31d is formed on an inclined surface with respect to the pulling direction α of the mandrel 31. The step portion 32d of the annular body 32 is also formed on the inclined surface with respect to the pulling direction α of the mandrel 31 similarly to the mandrel 31. The breaking portion 31e is the minimum diameter of the mandrel 31. Further, as shown in FIG. 7, the stepped portion 3d provided in the mandrel 31 is determined by the inclination angle of the stepped portion 32d provided in the annular body 32 with respect to the axis of the mandrel 31.
The inclination angle of the 1d mandrel 31 with respect to the axis is gentler.

In the blind rivet, as shown in FIG. 7, W is the distance between the rear surface of the head portion 31f of the mandrel 31 and the tip of the annular body 32, X is the length of the effective portion for expanding and the member to be fastened. Length depending on the total thickness of
Is the length of the effective portion for buckling and is a length that depends on the total thickness of the member to be fastened in the same manner as X, Z1 is the distance from the bulging start position to the rear end of the flange 32h, and Z2 is the bulging start position It is the distance from to the flange surface. Here, X ≧ Z2 is a condition for sufficient swelling, and W ≧ V is a condition for buckling after the swelling.

Using such a blind rivet,
In order to fasten the first member and the second member, which are members to be fastened, first, as shown in FIG. 8, the annular bodies 32 and 32 are inserted into the holes 3a and 4a of the first member 3 and the second member 4, respectively. Is inserted from the side from which the mandrel 31 is pulled out. In this inserted state, the inner circumferences of the holes of the first member 3 and the second member 4 and the annular body 32
A gap S is formed between the second annular tubular portion 32g and the outer periphery of the second annular tubular portion 32g.

Next, as shown in FIG.
In the pulling-out direction α and the step 31 of the mandrel 31
d is pressed against the step 32d of the annular body 32 to start expanding. Thus, an external force f3 is applied from the step 31d of the mandrel 31 to the inside of the step 32d of the annular body 32. Due to this external force f3, the first member 3 and the second
The portion of the annular body 32 corresponding to the holes 3a, 4a of the member 4 expands. Then, as the amount of pulling out the mandrel 31 increases and the amount of expansion increases, the inner diameters of the holes 3a, 4a of the first member 3 and the second member 4 and the annular body 3
The gap S between the second outer diameter and the second outer diameter is reduced.

At this time, an annular groove portion 32j is formed on the base end side of the small-diameter hole portion 32c so as to absorb a portion where the effective volume of the expanded diameter protrudes from the gap S. When the second annular body portion 32g constituting the portion 4a expands and the effective volume is larger than the volume of the gap S between the holes 3a, 4a of the object to be fastened and the outer periphery of the annular body 32, it can be absorbed. it can.

Next, as shown in FIG. 10, the mandrel 31 is further pulled in the pulling-out direction α from the state of FIG. 9 to terminate the expansion, and the “body expansion step” is completed. In a state in which the “body expansion step” has been completed, it has occurred between the inner periphery of the holes 3a, 4a of the first member 3 and the second member 4 and the outer periphery of the second annular cylindrical portion 32g of the annular body 32. The gap S is filled with the expanded portion of the second annular tubular portion 32g. Further, due to the annular concave portion 32i provided at the root of the flange portion 32h of the annular body 32, the expanded portion of the second annular cylindrical portion 32g is expanded to the end of the gap S. Thereby, the first member 3 and the second member 4 are in close contact with the second annular tubular portion 32g of the annular body 32. Then, the head portion 31f of the mandrel 31 contacts the distal end portion of the annular body 32.

Since the rear surface 31r of the head portion 31f forms an acute angle between the surface of the mandrel 31 and the surface that comes into contact with the annular body 32, the rear surface 31r of the head portion 31f extends axially from the rear surface 31r of the head portion 31f to the distal end of the annular body 32. A heading force acts, and the desired buckling can be obtained without the head portion 31f slipping into the annular body 32. Therefore, stable fastening can be performed without performing high-strength processing. Further, since the distal end portion of the annular body 32 is urged in the axial direction, the mandrel 31 is swaged to the annular body 332,
The mandrel 31 does not fall off after fastening.

Next, as shown in FIG. 11, the mandrel 31 is further pulled in the pulling-out direction α from the state of FIG. 10 to buckle the first annular body 32f of the annular body 32, thereby performing a “body buckling step”. By terminating the mandrel in the pulling-out direction α and breaking the mandrel at the breaking portion 31e.
The fastening is completed.

According to the blind rivet of this embodiment, since there is almost no gap S between the outer diameter of the annular body 32 and the holes of the first member 3 and the second member 4, the shearing of the annular body 31 The first member 3 and the second member 4 do not move even when receiving an external force that gives a force. That is, the outer diameter of the annular body 32 before fastening and the hole portions 3a,
Even if there is a margin between the position and the position 4a, the position does not change over time after fastening.

Further, it is not necessary to use a jig for correcting the warpage of the first member 3 and the second member 4 at the time of fastening. In addition, the number of contact portions between the annular body 32 and the member to be fastened is larger than that of the related art, and it is firmly fixed, so that the number of rivet hit points can be reduced.

Further, since the swelling occurs almost uniformly in the radial direction of the annular body 32, the hole 3a of the first member 3 and the second
Since the hole 4a of the member 4 is automatically aligned, the hole 3
Even if there is play in a and 4a, the first member 3 and the second member 4 are not shifted and fastened after fastening.

Further, since the "body buckling step" is started after the "body swelling step" is completed, the pulling force of the mandrel 31 required for the "body swelling step" and the "body buckling step" are required. It is not necessary to apply the pulling force of the mandrel 31 at the same time, and the load applied to the mandrel 31 at the time of fastening can be divided, whereby the pulling force required at the time of fastening can be reduced. Also,
The mandrel 31 itself having a low tensile strength can be used.

The step portion 32 between the annular body 32 and the mandrel 31 of the blind rivet of the present invention.
The shapes of d and 31d are not only the tapered shape as shown in FIG. 7 but also the stepped portions 32d and 31d having a circular cross section as shown in FIG.
It may be 31d.

[0072]

As is apparent from the above description, according to the present invention, the head portion of the mandrel is formed so that the angle formed between the surface of the mandrel contacting the annular body and the axis of the mandrel is acute. A force is applied from the rear surface to the tip of the annular body toward the axial center, and the desired buckling can be obtained without the head portion slipping into the annular body. Therefore, stable fastening can be performed without performing high-strength processing. Further, since the distal end portion of the annular body is urged in the axial direction, the mandrel is swaged to the annular body, and the mandrel does not fall off after fastening.

The mandrel has a head portion abutting on one end of the annular body, and a shaft portion connected to the head portion and inserted through the annular body. A first body portion having a large diameter connected to the first body portion, a second body portion having a smaller diameter than the first body portion, and a step portion provided between the first body portion and the second body portion. , The movement of the member to be fastened can be prevented even when a shear force is applied to the annular body by pulling out the mandrel.

Since the step portion is an inclined surface formed at a predetermined angle between the first body portion and the second body portion, the mandrel can be pulled out smoothly and efficiently.

The mandrel includes a shaft portion inserted into the annular body, and a head portion connected to one end of the shaft portion. The shaft portion is configured to fasten a member to be fastened in order from the head portion side. A first body portion having an effective length for use, an enlarged portion for expanding the outer diameter of the annular body, and a second body connected to the enlarged portion and held for plastically deforming the annular body. Since it is provided with a portion, it is advantageous in strength.

Since the shaft portion has a broken portion that is broken after fastening, the shaft portion can have any length after fastening. Since the break portion is continuous with the step portion, processing is easy. Since the break portion is a V-groove, the break position can be set accurately. Since the diameter of the breaking portion is the minimum diameter of the entire mandrel, it can be broken by applying tension to the mandrel.

The annular area obtained by removing the sectional area of the second body from the sectional area of the first body is obtained by subtracting the sectional area of the outer shape of the annular body from the sectional area of the hole of the member into which the annular body is inserted. Since the area is the same or larger than the annular area, the gap can be sufficiently filled by the expanded diameter.

Since the hole of the annular body is tapered from the flange side to the other end, the machining of the annular body is easy. When the effective volume due to the bulge in the second annular body constituting the second hole is larger than the volume of the gap between the hole of the object to be fastened and the outer periphery of the annular body, the effective volume due to the bulge is equal to the gap. Since there is provided an absorbing portion for absorbing the protruding portion, the gap can be sufficiently filled.

Since there is a small diameter portion smaller than the tip diameter of the shaft portion between the head portion of the mandrel and the shaft portion,
After fastening, the leading end of the annular body is integrated with the recessed mandrel. Since the annular body is filled with the expanded diameter of the annular body up to the end of the gap formed by the member to be fastened and the annular body, the gap created after the fastening is eliminated, and the workability and the assemblability are impaired. Therefore, even if the present invention is applied to a portion where a large load is applied, such as the lowermost stage of a copying machine, it is possible to perform fastening without causing a change in position over time.

[Brief description of the drawings]

FIG. 1 is a sectional view of a blind rivet according to an embodiment of the present invention.

FIG. 2 is a view for explaining fastening of the blind rivet of FIG. 1;

FIG. 3 is a view for explaining a modified example of the blind rivet of FIG. 1;

FIG. 4 is a view for explaining a modified example of the blind rivet of FIG. 1;

FIG. 5 is a view for explaining a modified example of the blind rivet of FIG. 1;

FIG. 6 is a view for explaining another embodiment of the blind rivet of the present invention.

FIG. 7 is a view for explaining another embodiment of the blind rivet of the present invention.

FIG. 8 is a view for explaining fastening of the blind rivet of FIG. 7;

FIG. 9 is a view for explaining fastening of the blind rivet of FIG. 7;

FIG. 10 is a view for explaining fastening of the blind rivet of FIG. 7;

FIG. 11 is a view for explaining fastening of the blind rivet of FIG. 7;

FIG. 12 is a view for explaining a modified example of the blind rivet of FIG. 7;

FIG. 13 is a diagram for explaining an outline of each unit of the copying machine.

FIG. 14 is a view for explaining fastening of a conventional blind rivet.

FIG. 15 is a sectional view of a conventional blind rivet.

FIG. 16 is a diagram for explaining a conventional blind rivet fastening state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mandrel 1a Shaft part 1b 1st trunk | drum 1c 2nd trunk | drum 1d Step difference part 1e Breaking part 1f Head part 1r Rear surface of a head part 2 Annular body 2b Large diameter hole part 2c Small diameter hole part 2d Step part 2e High strength part 2f First annular body 2g Second annular body 2h Flange 3 3 First member 4 Second member 11r Rear surface of head portion 21r Rear surface of head portion 31r Rear surface of head portion

Claims (18)

[Claims] 1. A blind rivet mandrel that is inserted into an annular body to plastically deform the annular body, wherein the mandrel is connected to a head portion abutting one end of the annular body and to the head portion. A shaft portion inserted through the annular body, wherein the head portion has an acute angle between a surface that contacts the annular body and an axis of the mandrel, the blind rivet being a mandrel. 2. A blind rivet mandrel which is inserted into an annular body to plastically deform the annular body, wherein the mandrel is connected to a head portion abutting on one end of the annular body and to the head portion. A shaft portion inserted through the annular body, the shaft portion having a first body portion having a large diameter connected to the head portion, and a second body having a smaller diameter than the first body portion. And a step portion provided between the first body portion and the second body portion, wherein the head portion has an acute angle between a surface contacting the annular body and a mandrel shaft. A blind rivet mandrel characterized by: 3. The blind rivet mandrel according to claim 2, wherein the step portion is an inclined surface formed at a predetermined angle between the first body portion and the second body portion. 4. The blind rivet mandrel according to claim 2, wherein said mandrel is harder than said annular body. 5. A mandrel for a blind rivet that is inserted through an annular body to plastically deform the annular body, wherein the mandrel is connected to a shaft portion inserted through the annular body and a head connected to one end of the shaft portion. And the shaft portion, in order from the head portion side, a first body portion having an effective length for fastening of the member to be fastened, an expanded portion for expanding the outer diameter of the annular body, and A second body portion connected to the enlarged diameter portion via a step portion and held for plastically deforming the annular body, wherein the head portion forms a surface in contact with the annular body and a shaft of a mandrel. A blind rivet mandrel characterized by an acute angle. 6. The blind rivet mandrel according to claim 2, wherein the shaft portion has a break portion that is broken after fastening. 7. A mandrel for a blind rivet according to claim 6, wherein said break portion is continuous with said step portion. 8. The blind rivet mandrel according to claim 6, wherein said breaking portion is a V-groove. 9. The blind rivet mandrel according to claim 6, wherein the break portion is disposed on a side opposite to the head portion with the step portion interposed therebetween. 10. The blind rivet mandrel according to claim 6, wherein the diameter of the breaking portion is a minimum diameter of the entire mandrel. 11. An annular area obtained by subtracting a sectional area of the second body from a sectional area of the first body is a sectional area of an outer shape of the annular body based on a sectional area of a hole of a member to which the annular body is inserted. The blind rivet mandrel according to claim 2 or 5, wherein the mandrel is the same as or larger than the annular area excluding. 12. A mandrel for a blind rivet that is inserted into an annular body to plastically deform the annular body, wherein the mandrel has a head portion in contact with one end of the annular body, and a tapered conical shape connected to the head portion. Wherein the head portion has an acute angle between a surface abutting the annular body and a shaft of the mandrel. 13. A blind rivet to be inserted and fastened to a member to be fastened by being inserted from one side thereof, wherein a means for expanding a portion of the annular body that contacts the member to be fastened as the mandrel moves in the annular body at the time of fastening. A blind rivet, wherein the head portion of the mandrel has an acute angle between a surface that contacts the annular body and an axis of the mandrel. 14. A blind rivet comprising: an annular body inserted through a member to be fastened; and a mandrel inserted through the annular body and plastically deforming the annular body, wherein the mandrel is provided at one end of the annular body. A head portion connected to the head portion, a shaft portion inserted into the annular body, and the shaft portion has a first body portion having a large diameter connected to the head portion; A second body formed to be smaller in diameter than the first body, and a step provided between the first body and the second body; A first hole, a second hole which is continuous with the first hole via a step, and has a smaller diameter than the first hole, and a flange provided at an end of the second hole. ,
A blind rivet, wherein the head portion has an acute angle between a surface that contacts the annular body and a shaft of a mandrel. 15. A blind rivet comprising: an annular body inserted through a member to be fastened; and a mandrel inserted through the annular body and plastically deforming the annular body, wherein the annular body has the second hole formed therein. In a case where the effective volume due to the swelling of the second annular body portion is larger than the volume of the gap between the hole of the fastened body and the outer periphery of the annular body, the portion where the effective volume due to the swelling protrudes from the gap is determined. Along with an absorbing portion that absorbs, at least an end portion of a gap formed by the member to be fastened and the annular body is provided with a groove having a size that is filled by an expanded diameter of the annular body, and the head portion is A blind rivet, wherein an angle between a surface contacting the annular body and an axis of the mandrel is acute. 16. A blind rivet comprising: an annular body inserted through a member to be fastened; and a mandrel inserted through the annular body and plastically deforming the annular body, wherein the mandrel is provided at one end of the annular body. A head portion connected to the head portion, a shaft portion connected to the head portion and inserted into the annular body, wherein the shaft portion has a large-diameter first body portion connected to the head portion; A second body formed to be smaller in diameter than the first body, and a step provided between the first body and the second body, wherein the step is
The annular body has a large-diameter first hole portion and a step portion formed between the first body portion and the second body portion. A second hole having a smaller diameter than the first hole, and a flange provided at an end of the second hole.
The step portion is an inclined surface, and the inclined surface of the mandrel is formed more gently than the inclined surface of the annular body, and the head portion is formed between a surface that contacts the annular body and the axis of the mandrel. A blind rivet characterized by an acute angle. 17. The blind rivet according to claim 13, wherein a small-diameter portion having a diameter smaller than a tip diameter of the shaft portion is provided between the head portion and the shaft portion of the mandrel. 18. A blind rivet structure comprising: an annular body inserted through a member to be fastened; and a mandrel inserted through the annular body to plastically deform the annular body. An end of a gap formed by the annular body is filled with the expanded diameter of the annular body, and the head portion has an acute angle between a surface contacting the annular body and an axis of a mandrel. Blind rivet structure.