JP2009180347A - Blind rivet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blind rivet for surely preventing the falloff of a mandrel from a rivet body after competing fastening while allowing easy assembly of the rivet body and the mandrel together without the falloff of the mandrel in the assembled condition. <P>SOLUTION: The blind rivet comprises the rivet body having a cylindrical trunk and a flanged head formed at one end of the trunk, and the mandrel having a shaft part inserted through the rivet body and a large diameter head formed at one end of the shaft part, the shaft part having a rupture constricted portion. The inner diameter part of the rivet body has a large diameter portion on the trunk side and a small diameter portion on the head side. The mandrel has an uneven portion formed on the surface of the shaft part between the head and the constricted portion along the longitudinal direction of the shaft part. The uneven portion is serratedly formed so that the face of a protruded portion at the side of the constricted portion is inclined. The diameter of the protruded portion is larger than that of the large diameter portion of the rivet body. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a blind rivet, and more specifically, a blind capable of improving the fixing strength of a mandrel with respect to a rivet body (sleeve) upon completion of fastening and effectively preventing the mandrel from falling off the rivet body. Regarding rivets.

In general, a blind rivet is composed of a hollow cylindrical rivet body (sleeve) having a flange-shaped head at one end and a mandrel inserted into the rivet body having a large-diameter head at one end. ing.
In the blind rivet having such a structure, it is necessary to fix the rivet body and the mandrel when the fastening is completed so that the mandrel does not fall off from the rivet body after the fastening is completed.

As a fall-off prevention structure in a conventional blind rivet, for example, structures as described in Patent Documents 1 to 4 below can be exemplified.
In the blind rivet described in Patent Document 1, a large-diameter drop-off prevention portion is provided in the mandrel shaft, and the drop-off prevention portion is press-fitted into the rivet body at the time of fastening, whereby the rivet body and the mandrel are fixed. .
However, since the structure disclosed in Patent Document 1 fixes the mandrel and the rivet body only by press-fitting, sufficient fixing strength cannot be obtained.
In addition, although patent document 1 describes increasing the fixing strength of the mandrel to the rivet body by providing a circumferential groove in the drop-off prevention portion, the meat of the rivet body is difficult to enter the circumferential groove. The effect of increasing the strength is hardly obtained.
Moreover, in order to provide a circumferential groove, since a rolling process is required, manufacturing cost becomes high.
Furthermore, in order to fix the mandrel to the rivet body, it is necessary to completely deform (expand the diameter) one end of the rivet body (the end opposite to the flange), and in addition, it is formed on the outer periphery of the rivet body. Since the mandrel needs to be pulled out to the position of the reduced diameter portion, a long mandrel pulling stroke is required.

In the blind rivet described in Patent Document 2, a large number of circumferential grooves are formed over substantially the entire length of the mandrel shaft, and when the fastening is completed, these circumferential grooves bite into the inner peripheral surface of the rivet body. The fixing strength of the mandrel to the rivet body can be increased.
However, this disclosed technique requires a large load when the mandrel is fitted into the rivet body in the assembly process of the rivet body and the mandrel.
In addition, the manufacturing cost is high because a rolling process is required to manufacture the mandrel, and the mandrel shaft part protrudes greatly from the flange part surface of the rivet body after the fastening is completed. Get in the way.

In the blind rivets described in Patent Documents 3 and 4, the mandrel is prevented from falling off the rivet body because the head of the mandrel is wrapped in one end of the rivet body when the fastening is completed.
However, in these disclosed technologies, when the caulking allowance cannot be made large, such as when there is a wall on the mandrel head side (when the pulling stroke of the mandrel is small), the mandrel head is sufficiently placed in the rivet body. There is a risk that the mandrel will rattle or fall off after completion of fastening.

JP 2007-278437 A JP-A-10-274220 Japanese Utility Model Publication No. 55-122519 JP 61-171910 A

  The present invention has been made to solve the above-described problems of the prior art, and can reliably prevent the mandrel from falling off the rivet body after completion of fastening, and the rivet body and mandrel. Can be assembled easily, and the mandrel will not drop off in the assembled state, and even if the mandrel pulling stroke is small, the mandrel can be fixed to the rivet body. Provided is a blind rivet that does not protrude from the surface of the flange portion of the main body and can reduce the manufacturing cost.

  According to a first aspect of the present invention, there is provided a rivet body comprising a cylindrical body, a flange-shaped head formed at one end of the body, a shaft inserted into the rivet body, and the shaft A blind rivet comprising a mandrel having a large-diameter head formed at one end of the shaft and a constricted portion for breaking at the shaft portion, wherein the inner diameter portion of the rivet body is The mandrel is formed on the surface of the shaft portion between the head portion and the constricted portion along the length direction of the shaft portion. The concavo-convex portion is formed in a saw blade shape in which the constricted portion side surface of the convex portion is an inclined surface, and the convex portion is larger in diameter than the large-diameter portion of the rivet body. It relates to a blind rivet characterized by being.

  The invention according to claim 2 relates to the blind rivet according to claim 1, wherein the concave and convex portions are formed at two locations facing each other across the central axis of the shaft portion.

  The invention according to claim 3 relates to the blind rivet according to claim 1 or 2, wherein the surface hardness of the mandrel is higher than the surface hardness of the rivet body.

  The invention according to claim 4 relates to the blind rivet according to claim 2, characterized in that the uneven portions formed at the two locations are out of phase in the shaft portion length direction.

  The invention according to claim 5 relates to the blind rivet according to claim 4, wherein the material of the mandrel is iron or an iron alloy, and the material of the rivet body is a JIS 5000 series aluminum alloy.

According to the first aspect of the present invention, the projections and depressions are formed on the shaft portion of the mandrel, and the diameter of the projection is larger than that of the large-diameter portion of the rivet body. The portion bites into the inner surface of the rivet body, and it is possible to prevent the mandrel from falling off the rivet body.
In addition, the concave and convex portions are formed in a saw blade shape with the constricted portion side surface of the convex portion being an inclined surface, so that the meat of the rivet body can easily enter the concave portion, and the convex portion is securely attached to the inner surface of the rivet main body at the time of fastening. Can bite into. Therefore, the mandrel is firmly fixed to the rivet body, and the mandrel can be reliably prevented from falling off from the rivet body after completion of the fastening.
Further, in the assembly process of the rivet body and the mandrel, the load required when the mandrel is fitted into the rivet body is reduced, and the assembly can be easily performed. In addition, the pull-out load of the mandrel can be reduced at the time of fastening, and the fastening work can be easily performed. On the other hand, after the fastening, the resistance in the direction in which the mandrel falls off increases, so that the removal is effective. Can be prevented.
Furthermore, the mandrel can be fixed to the rivet body at any position of the rivet body regardless of the degree of deformation of the rivet body (the degree of caulking). Can be securely fixed.
In addition, since the mandrel breaks at the constricted portion, the shaft portion of the mandrel does not protrude from the surface of the flange portion of the rivet body after the fastening is completed.

According to the invention of claim 2, since the concavo-convex portions are formed at two locations facing each other across the central axis of the shaft portion, the meat of the rivet body can easily enter the concave portion, and the convex portion at the time of fastening Can be surely bitten by the inner surface of the rivet body.
Moreover, the falling-off preventing function can be imparted without requiring a rolling process, and the manufacturing cost can be kept low.

According to the invention according to claim 3, since the uneven portions formed at two places have the phases of the uneven portions shifted in the length direction of the shaft portion, the insertion load in the assembly process of the rivet body and the mandrel and at the time of fastening It becomes possible to make the pull-out load of the mandrel smaller.
Furthermore, because the phase of the unevenness is shifted, at the time of assembly or fastening, the portion of the mandrel that touches the uneven portion of the shaft is deformed so as to wave in accordance with the unevenness, and accordingly the elastic force (restoring force) is applied to the shaft. ) Can more effectively prevent the mandrel from falling off during assembly and fastening.

  According to the invention which concerns on Claim 4, when the surface hardness of a mandrel is higher than the surface hardness of a rivet main body, the convex part of a mandrel can be made to bite into the inner surface of a rivet main body at the time of completion of fastening.

  According to the invention of claim 4, the mandrel is made of iron or an iron alloy, and the rivet body is made of a JIS 5000 series aluminum alloy. It is possible to securely bite the inner surface of the main body.

Hereinafter, a preferred embodiment of a blind rivet according to the present invention will be described with reference to the drawings.
FIG. 1 is a view showing an example of a blind rivet according to the present invention.
The blind rivet according to the present invention includes a rivet body (sleeve) (1) and a mandrel (2) combined with the rivet body (1).

In the present invention, the materials of the rivet body (1) and the mandrel (2) are not particularly limited, but are selected so that the surface hardness of the mandrel (2) is higher than the surface hardness of the rivet body (1). Specifically, the hardness of the convex portion formed on the surface of the shaft portion of the mandrel (2) to be described later is made higher than the hardness of the inner surface (the inner surface of the inner diameter portion) of the rivet body (1).
This is because, when the blind rivet is assembled and fastened, as will be described later, the convex portion formed on the surface of the shaft portion of the mandrel (2) is securely bited into the inner surface of the rivet body (1).
Specifically, as the material of the rivet body (1), an aluminum alloy such as JIS5000 series is preferably used, and as the material of the mandrel, iron or an iron alloy is preferably used.

The rivet body (1) is composed of a cylindrical body (3) and a head (4) formed in a flange shape at one end of the body (3).
FIG. 2 is a cross-sectional view showing an example of the rivet body (1), in which (a) shows a type with a long body and (b) shows a type with a short body.
As shown in the drawing, the inner diameter portion of the rivet body (1) has a large diameter portion (5) on the body portion (3) side and a small diameter portion (6) on the head portion (4) side.
Specifically, the large diameter part (5) is formed over a range from the other end of the trunk part (3) to the midway part, and the small diameter part (6) is formed from the midway part to the head part (4). The remaining range up to is formed.

The small diameter portion (6) may be a straight hole over the entire length, but the other end side (head side) may be formed larger than the one end side (body side) of the small diameter portion (6). .
In this case, the small diameter portion (6) may be a tapered hole that gradually increases in diameter from one end side to the other end side, or may be a stepped hole that gradually increases in diameter from one end side to the other end side. . In the example of illustration, the small diameter part (6) is formed from the straight hole part (61) formed in the one end side, and the taper hole part (62) formed in the other end side.
When the other end side (head side) is formed larger than one end side (body side) of the small diameter portion (6), the one end side must always be smaller in diameter than the large diameter portion (5). However, the other end side may be larger in diameter than the large diameter portion (5).

FIGS. 3A and 3B are views showing the mandrel (2), in which FIG. 3A is a front view, FIG. 3B is a view in the A direction arrow, and FIG.
The mandrel (2) has a shaft portion (7) inserted through the rivet body (1) and a large-diameter head (8) formed at one end of the shaft portion (7). A constricted part (9) for breaking is formed in the part (7). Moreover, the other end of the shaft portion (7) has a quadrangular pyramid shape.

The head (8) is formed in a dish shape that gradually decreases in diameter toward the shaft (7). In the illustrated example, the inner angle (α) of the taper is 90 °.
Four cutting blades (not shown) are formed at intervals of 90 ° in the circumferential direction on the tapered surface toward the shaft portion (7) of the head portion (8). These cutting blades play a role of cutting and expanding the diameter of the other end of the body portion of the rivet body (1) at the time of fastening.
A circular recess (10) is formed on the surface of the head (8).
The recess (10) is formed by denting the flat head surface with the head (8) placed in a predetermined shape mold, and by denting the head surface. The cutting edge can be formed sharper in the mold.

On the surface of the shaft portion (7), an uneven portion (11) is formed along the length direction of the shaft portion at a portion between the head portion (8) and the constricted portion (9).
The outer diameter of the shaft portion (7) is basically smaller than the inner diameter of the small diameter portion (6) of the rivet main body (1), but only at the convex portion of the concave and convex portion (11). The diameter is larger than the large diameter part (5) of (1).
In other words, the size relationship between the diameters of the rivet body (1) and the mandrel (2) is “mandrel shaft (excluding projections)” <“rivet body small diameter part” <“rivet body large diameter part. "<" Convex part of mandrel shaft ".
Thus, in the assembled state (see FIG. 1), the convex portion of the mandrel (2) bites into the inner surface of the large diameter portion (5) of the rivet body (1), and the mandrel (2) falls off from the rivet body (1). It is prevented.
Further, when the fastening is completed, the mandrel (2) is firmly fixed to the rivet body (1) by the convex part firmly biting into the inner surface of the small diameter part (6) of the rivet body (1). This prevents the dropout.

The concavo-convex portion (11) is formed in a saw blade shape with the constricted portion side surface of the convex portion being a slope, and the angle (β) of the slope is, for example, 45 °.
As described above, the concave and convex portion (11) is formed in a saw blade shape in which the constricted portion side surface of the convex portion is a slope, so that in the assembly process of the rivet body (1) and the mandrel (2), the mandrel The load required for fitting (2) into the rivet body (1) is reduced and can be easily assembled.
Further, at the time of fastening, the pulling load of the mandrel (2) can be reduced, so that the fastening work can be easily performed. On the other hand, after the fastening, the resistance in the direction in which the mandrel (2) falls off increases, so that the falling off can be effectively prevented.

The concavo-convex portion (11) is not formed over the entire circumference of the shaft portion surface (over 360 °), but is formed only in a part of the circumferential direction on the shaft portion surface.
Thus, by forming the concavo-convex part (11) only in a part of the circumferential direction on the surface of the shaft part, the meat of the inner surface of the rivet body (1) can easily enter the concave part, and the rivet body (1) The fixing strength of the mandrel (2) can be increased.
Further, since no rolling process is required, the manufacturing cost can be kept low.

When forming the concavo-convex part (11) only in a part in the circumferential direction, it is preferable to form 2 to 4 places at equally spaced positions in the circumferential direction. As shown in FIG. ) Is most preferably formed at two locations facing each other across the central axis.
This is because the effect of increasing the fixing strength of the mandrel (2) with respect to the rivet body (1) described above is obtained when the concavo-convex portion (11) is formed at two locations facing each other across the central axis of the shaft portion (7). This is because it is most prominent.

It is preferable that the concavo-convex portion (11) formed only in a part of the surface of the shaft portion in the circumferential direction shifts the phase of the concavo-convex in the shaft portion length direction.
FIG. 4 shows an example in which the concavo-convex phase is shifted in the axial length direction of the concavo-convex portion (11) formed at two locations facing each other across the central axis of the shaft portion (7).
In this way, by shifting the phase of the irregularities, it is possible to further reduce the insertion load in the assembly process of the rivet body (1) and the mandrel (2) and the pull-out load of the mandrel (2) at the time of fastening.
Further, by shifting the phase of the unevenness, at the time of assembling or fastening, the portion corresponding to the uneven portion (11) of the shaft portion (7) of the mandrel (2) is deformed so as to wave in accordance with the unevenness. By generating an elastic force (restoring force) in the portion (7), it is possible to more effectively prevent the mandrel from falling off during assembly or fastening.

FIG. 5 is a view showing a state in which two plate-like members to be fastened are fastened using the blind rivet according to the present invention, where (a) shows a case where the fastened member is thick and (b) shows a fastened state. The case where a member is thin is shown, respectively.
As shown in the figure, when the fastening is completed, the mandrel (2) breaks at the constricted portion (9), and the head (8) of the mandrel (2) expands the large diameter portion (5) of the rivet body (1). is doing. Moreover, the convex part formed in the axial part (7) of the mandrel (2) bites into the inner surface of the small diameter part (6) of the rivet body (1).

Thus, when the fastening is completed, the mandrel (2) is firmly fixed to the rivet body (1) by the convex portion of the mandrel (2) biting into the small diameter part (6) of the rivet body (1). The Therefore, it is possible to reliably prevent the mandrel (2) from dropping from the rivet body (1) after completion of the fastening.
Moreover, even when the degree of deformation of the rivet body (1) is large as shown in FIG. 5 (a) (when the fastened member is thick), the deformation of the rivet body (1) as shown in FIG. 5 (b). Even when the degree is small (when the fastened member is thin), the convex part of the mandrel (2) bites into the small diameter part (6) of the rivet body (1), and the mandrel (2) is strong against the rivet body (1). Fixed to.
That is, it becomes possible to fix the mandrel (2) to the rivet body (1) at an arbitrary position of the rivet body regardless of the degree of deformation of the rivet body (1).
Therefore, even when the extraction stroke of the mandrel (2) is small, the mandrel (2) can be reliably fixed to the rivet body (1).

  The blind rivet according to the present invention can be widely used in construction sites and factories.

It is a figure which shows an example of the blind rivet which concerns on this invention. It is sectional drawing which shows the example of a rivet main body, Comprising: (a) is a type with a long trunk | drum, (b) has shown the type with a short trunk | drum. It is a figure which shows a mandrel, Comprising: (a) is a front view, (b) is an A direction arrow view, (c) is a B direction arrow view. An example is shown in which the phase of the unevenness is shifted in the axial direction of the uneven portions formed at two locations facing each other across the central axis of the shaft portion. It is a figure which shows the state which fastened two plate-shaped to-be-fastened members using the blind rivet which concerns on this invention, Comprising: (a) is a case where a to-be-fastened member is thick, (b) is a case to which a to-be-fastened member is thin Respectively.

Explanation of symbols

1 Rivet body 2 Mandrel 3 Body 4 Head (Rivet body)
5 Large diameter part 6 Small diameter part 7 Shaft part 8 Head (mandrel)
9 Constriction 10 Recess 11 Concave

Claims (5)

A rivet body comprising a cylindrical body and a flange-shaped head formed at one end of the body;
Blind rivet comprising a shaft portion inserted into the rivet body and a mandrel having a large-diameter head formed at one end of the shaft portion, and a constriction portion for breakage formed in the shaft portion Because
The inner diameter portion of the rivet body has a large diameter portion on the trunk portion side and a small diameter portion on the head side, respectively.
The mandrel has a concavo-convex portion formed along the shaft length direction on the shaft surface between the head and the constricted portion,
The concavo-convex part is formed in a saw blade shape in which the surface of the constriction part side of the convex part is a slope,
The blind rivet characterized in that the convex portion has a larger diameter than the large-diameter portion of the rivet body.   2. The blind rivet according to claim 1, wherein the concavo-convex portion is formed at two locations facing each other across the central axis of the shaft portion.   3. The blind rivet according to claim 2, wherein the concavo-convex portions formed at the two locations are out of phase in the shaft length direction.   The blind rivet according to any one of claims 1 to 3, wherein the mandrel has a surface hardness higher than that of the rivet body.   The blind rivet according to claim 4, wherein a material of the mandrel is iron or an iron alloy, and a material of the rivet body is a JIS 5000 series aluminum alloy.

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