JP2003336617A - Insert fastening member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insert fastening member easily pressed into an installation hole of a work, and fixed by high fastening force. <P>SOLUTION: In this insert fastening member 1 pressed and fixed in the installation hole 31, the periphery of a cylinder shaft part 2 formed with a female screw 3 is formed with a plurality of cross-sectionally triangular projecting stripes 10, a slant face 11 slanting from the projecting stripe apex is formed on the press-in tip side of each the projecting stripe 10, and the cylinder shaft part 2 is formed with a plurality of slits 20 each open on the press-in tip side. By pressing the insert fastening member 1 into the installation hole 31 of the work 30 and screwing a screw 5 into the installation hole 31, the projecting stripes 10 are made to bite into the installation hole 31. Accordingly, when fixing a fastened member to the work 30 of a soft material by the screw 5, workability or a working cost is reduced. Since no chip falls, a bad influence such as a short circuit of an electronic component does not occur even if the electronic component is disposed below the work 30. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is press-fitted into a mounting hole formed in a work made of a soft material having a relatively low hardness, such as an aluminum alloy or a magnesium alloy.
The present invention relates to an insert fastening member for fixing a member to be fastened by screwing a screw therein.

[0002]

2. Description of the Related Art Mobile phones, automobile parts, etc. are relatively soft for mounting electronic parts, etc.
Aluminum alloys, magnesium alloys, etc. are used.In this case, since electronic parts dislike dust and dirt, it is necessary to use so-called tapping screws that are screwed in while forming female threads with screws, when forming female threads. It is not preferred because the resulting chips fall onto electronic components. Therefore, conventionally, a female screw is formed in a separate step in advance, and the member to be fastened is fixed to the workpiece by screwing the female screw during assembly.
There is also one as shown in Japanese Patent No. 05085.

This is as shown in FIG. 8, in which a hollow grommet 101 having a flange 133 formed at one end is rotationally pressure-bonded to a mounting hole 131 formed in the work 130 in advance. Friction heat is generated between the work 130 and the flange portion 133 so that they are melt-welded. A tapping screw (not shown) is screwed into the grommet 101, and a tapping screw is screwed into the grommet 101 to fix a member to be fastened (not shown) to the work 130. There is. In addition to this, insert members of different materials are used to fix the member to be fastened to the work made of soft material with screws, but the structure is complicated, and chips still fall, so the effect is The current situation is that it is not widespread because it is insufficient.

[0004]

However, in order to fix a member to be fastened to a work made of a soft material, fixing with a screw is the most optimal in terms of workability and work cost, and its improvement is awaited. However, the present situation is that the optimal method has not been obtained due to various problems. In particular, when fixing a plate-shaped part to a work made of a soft material and fixing it while forming a female screw with a tapping screw, if the tightening torque of this screw is large enough, the female screw will be destroyed and the member to be fastened will be broken. It cannot be fixed to the work. Also, if electronic parts are placed below this work,
The female thread molding waste falls on this, and adverse effects such as short-circuiting of electronic parts occur. Further, as described above, when the grommet in which the female screw is formed on the work is rotationally pressure-bonded and the work and the grommet are melt-welded by frictional heat, the grommet may idle during screw tightening. In addition, there are some products in which a work made of such a soft material is sandwiched and a screw is screwed onto a cold rolled steel plate, etc. for screwing, but the product becomes thicker by that amount, making the product lighter and thinner. Is no longer possible. On the other hand, since the production of the grommet is usually carried out by cutting, there are various problems such as a high processing cost, a relatively high cost, and an unsuitability for mass production.

An object of the present invention is to solve the above problems and to obtain an insert fastening member which can be easily press-fitted into a mounting hole of a work and can be fixed with a high tightening force.

[0006]

An object of the present invention is to attach holes 3 formed in a work 30 made of a soft material having a relatively low hardness.
In the insert fastening member in which the screw 5 is screwed into the insert fastening member to fix the fastened member 32, the outer circumference of the cylindrical shaft portion 2 of the fastening member having the female screw 3 into which the screw 5 is screwed is formed. A plurality of protrusions 1 with a triangular cross section in the axial direction at intervals.
0 is formed, and a slope 11 is provided on the press-fitting tip side of the projection 10 so as to incline from the projecting apex to the outer periphery of the cylindrical shaft portion 2, while the press-fitting tip side is opened along the axial direction of the cylindrical shaft portion 2. A plurality of slits 20 are formed at equal intervals in the circumferential direction, and the protrusions 10 are bited into the mounting holes 31 by press-fitting into the mounting holes 31 of the work 30 and screwing the screws 2 into the female threads 3. This is achieved by providing an insert fastening member as described above. In addition, the slope 11
Is an insert fastening member that is gradually inclined so as to be continuous with the outer periphery of the cylindrical shaft portion 2 on the press-fitting tip side, so that the press-fitting becomes smooth. Further, the slits 20 in these configurations have the protrusions 10 provided on the outer periphery of the cylindrical shaft portion 2 along the axis.
The same effect can be obtained by using the insert fastening member disposed in the middle of the above.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
It will be described with reference to FIG. In FIGS. 1 and 2, 1
Is an insert fastening member composed of a cylindrical shaft portion 2 having a cylindrical shape and having an internal thread 3 formed on the inner surface thereof, and a head portion 4 having a larger diameter than the cylindrical shaft portion 2 on the upper portion thereof. An upper end is connected to the head portion 4 on the outer periphery of the cylindrical shaft portion 2, and a protrusion 10 having a triangular cross section is integrally formed along the axis of the head portion 4. They are arranged at equal intervals on the outer circumference in three parts. The protrusions 10 are normally arranged at three equally divided positions, but in addition to this, the protrusions 10 may be arranged at a plurality of linearly divided positions. On the other hand, this protrusion 1
At the insertion tip side of 0, that is, at the lower end, an inclined surface 11 that is gradually inclined from the protrusion apex of the protrusion 10 is formed so that the tip is continuous with the peripheral surface of the cylindrical shaft portion 2. At the initial stage of press-fitting into 31, the resistance is prevented from being suddenly applied.

Further, the cylindrical shaft portion 2 is formed with a plurality of slits 20 opened at the press-fitting tip side along the axial direction of the cylindrical shaft portion 2 at equal intervals in the circumferential direction.
Is a protrusion 1 provided on the outer periphery of the cylindrical shaft portion 2 along the axis.
It is located in the middle of 0. This slit 10 is the head 4
Is cut down to a position approaching to, so that the press-fitting tip side of the cylindrical shaft portion 2 is bent in the radial direction. Therefore, when the screw 5 is screwed into the female screw 3, the cylindrical shaft portion 2 is expanded.
Although the slit 20 has three lines as in the case of the protrusion 10, if the slit 20 has a plurality of lines other than this, the function can be sufficiently exhibited.

When the insert fastening member 1 thus constructed is used to fix the fastened member 32, the cylindrical shaft portion is inserted into the mounting hole 31 formed in advance in the relatively soft work 30. 2 is press-fit as shown in FIG. At this time, since the mounting hole 31 is formed to have substantially the same diameter as the cylindrical shaft portion 2, the protrusion 10 is press-fitted while biting into the mounting hole 31 of the work 30. After the press-fitting work is completed, the fastened member 32 is placed on the work 30.
The component 5 is superposed with the centers of the mounting holes 31 aligned with each other, and then the screw 5 is screwed into the female screw 3 of the insert fastening member 1. As a result, the cylindrical shaft portion 2 of the insert fastening member 1 expands slightly, so that the protrusion 10
Further penetrates into the mounting hole 31 of the work 30 and the work 30
With respect to this, a retaining action and a rotation preventing action occur, and the fastened member 32 is fixed to the work 30 with the screw 5.

4 to 7 show a modification of the present invention, and FIGS. 4 and 5 show that the shape of the head 4 of the insert fastening member 1 in the above embodiment is circular. On the other hand, it has a shape in which the outer peripheral surface of the head portion 4 is a plane orthogonal to the quadrant. Furthermore, FIG. 6 and FIG.
Has a shape in which the outer peripheral surface of the head portion 4 is formed into a plane orthogonal to each of the six bisectors, which gives rise to different aesthetics.

[0011]

As is apparent from the above-described embodiment, the present invention is press-fitted into the mounting hole 31 of the work 30 made of a soft material, and the screw 5 is screwed into the mounting hole 31 to fix the member 32 to be fastened. In the insert fastening member 1, a plurality of protrusions 10 having a triangular cross section are formed along the axis at equal intervals on the outer periphery of a cylindrical shaft portion 2 in which a female screw 3 into which a screw 5 is screwed is formed. An inclined surface 11 is provided on the press-fitting tip side inclining from the projecting apex to the outer periphery of the cylindrical shaft portion 2. On the other hand, a plurality of slits 20 are formed on the cylindrical shaft portion 2 along the axis line and the press-fitting tip side is open. It is an insert fastening member configured to press the protrusion 10 into the mounting hole 31 by press-fitting into the female screw 31 and screwing the screw 5 into the female screw 3.

Therefore, workability and work cost are reduced when fixing the member to be fastened to the work made of a soft material with screws. In particular, as in the case where a tapping screw is directly screwed on a work made of a soft material, when the tightening torque is large, the problem that the female screw is broken and the screw cannot be fastened is solved. Further, since the insert fastening member on which the female screw is formed is press-fitted and fixed to the work and the member to be fastened is fixed to the insert fastening member with the screw, the electronic component is arranged below the work. However, no debris is dropped, and adverse effects such as short-circuiting of electronic parts do not occur. Further, since the insert fastening member has a projection, and the cylindrical shaft portion of the insert fastening member expands by screwing the screw into the female screw, the projection is bite firmly into the work, and during screwing of the screw. The insert fastening member will not slip or fall out. Moreover, since the screw is screwed and fixed to the insert fastening member fixed to the work, the product in which the screw is combined can be made thin, and the product can be made light and thin. In addition, since all the processes of this insert fastening member except female screw forming are performed by press forming, it is relatively inexpensive and mass production is possible.

On the other hand, since the slope 11 of the protrusion 10 is gradually inclined so as to be continuous with the outer periphery of the cylindrical shaft portion 2 on the press fitting tip side, the center of the mounting hole when the insert fastening member is press fitted into the mounting hole of the workpiece. It is pressed in smoothly without shifting.
Further, since the slit 20 of the cylindrical shaft portion 2 formed in these configurations is arranged in the middle of the projection 10 provided along the axis on the outer periphery of the cylindrical shaft portion 2, the slit of the cylindrical shaft portion at the time of press fitting is formed. The peculiar effects such as the uniform bending, the center of which does not always deviate from the center of the mounting hole and the press-fitting work is stabilized, are obtained.

[Brief description of drawings]

FIG. 1 is a sectional front view of an essential part of an insert fastening member showing an embodiment of the present invention.

FIG. 2 is a bottom view of FIG.

FIG. 3 is a cross-sectional view showing a usage state of the present invention.

FIG. 4 is a front view showing a modified example of the present invention.

FIG. 5 is a bottom view of FIG.

FIG. 6 is a front view showing another modification of the present invention.

FIG. 7 is a bottom view of FIG.

FIG. 8 is a perspective view of an essential part showing a conventional example of the present invention.

[Explanation of symbols]

1 Insert fastening member 2 Cylindrical shaft 3 female screw 4 head 5 screws 10 protrusions 11 slopes 20 slits 30 work 31 mounting holes 32 Fastened member

Claims (3)

[Claims] 1. A work (3) made of a soft material having a relatively low hardness.
In an insert fastening member that press-fits into a mounting hole (31) formed in (0) and screws (5) are screwed into this to fix a member (32) to be fastened, a female screw (3) into which the screw is screwed. A plurality of protrusions (10) having a triangular cross-section are formed in the axial direction at equal intervals on the outer periphery of the cylindrical shaft portion (2) of the fastening member in which the protrusions are formed on the tip end side of the protrusions. To the outer circumference of the cylindrical shaft, an inclined surface (11) is provided, and on the other hand, a plurality of slits (20) are formed in the cylindrical shaft at an equal interval in the circumferential direction, the slits (20) being open in the axial direction along the axial direction. The insert fastening member is characterized in that the protrusion is bited into the mounting hole by press-fitting into the mounting hole of the work and screwing the screw into the female screw. 2. The insert fastening member according to claim 1, wherein the inclined surface is gradually inclined so as to be continuous with the outer circumference of the cylindrical shaft portion on the press-fitting tip side. 3. The insert fastening member according to claim 1 or 2, wherein the slit is arranged at a middle of a protrusion provided on the outer periphery of the cylindrical shaft portion along the axis.