JP2005023944A - Screw-tightening structure of thin plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure large tightening torque when tightening thin plates to each other by tapping screws. <P>SOLUTION: A dish-shaped drawn portion 1b having a tightening hole 1a for tapping screws is formed on one thin plate 1, and a supporting portion 2b to support the dish-shaped drawn portion 1b from the inner side is provided on the other thin plate 2. The thickness of a tightened portion is substantially increased by the dish-shaped drawn portion 1b and the supporting portion 2b, and the axial force generated by the tightening torque is supported by the supporting portion 2b from the inner side of the dish-shaped drawn portion 1b to prevent the dish-shaped drawn portion 1b from being buckled. The thin plates can be tightened by the tightening torque larger than the torque when the thin plates reach up to an incomplete thread part below a neck of the screw thread. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a thin plate screw capable of securing a large tightening torque when the thin plates are tightened with two types of cross-tapped tapping screws (hereinafter simply referred to as tapping screws) defined in JIS B1122, for example. It relates to a fastening structure.
[0002]
[Prior art]
The tapping screw has a large screw pitch and a large difference between the crest diameter and the trough diameter. Therefore, when using such a tapping screw to fasten thin plates that are thinner than the screw pitch, if the fastening portion between the thin plates is flat, the fastening portion will be the neck of the tapping screw when tightened. It enters the lower incomplete threaded part and becomes an idle state, not only insufficient tightening but also a state where it cannot be loosened and removed.
[0003]
Therefore, a flat washer is pressed against the fastening part of the flat thin plate via an elastic body in a lying state, thereby ensuring the thickness of the fastening part and tapping from the bottom side of the dished washer. There has been proposed one in which a screw is inserted and tightened (see, for example, Patent Document 1).
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 59-30915
[Problems to be solved by the invention]
However, in the case where a flat washer is pressed against the fastening part of the flat thin plate via an elastic body in a lying state and is tightened with a tapping screw from the bottom side of the flat washer, Although the thickness of the fastening portion can be substantially increased by the concave shape, the elastic body disposed between the dish-shaped washer and the thin plate fastening portion is mainly used for sealing the fastening portion, and the fastening portion Therefore, the back-up force was weak, and it was impossible to prevent the fastening portions between the thin plates from being deformed by the fastening torque, and the fastening torque could not be increased.
[0006]
The technical problem of the present invention is to ensure as large a tightening torque as possible when thin plates are fastened with a tapping screw.
[0007]
[Means for Solving the Problems]
The screw fastening structure for a thin plate according to the present invention has the following configuration. That is, a thin plate screw fastening structure in which thin plates are fastened together with a tapping screw, and a plate-like diaphragm portion having a fastening hole for a tapping screw is formed on one thin plate, and a plate-like diaphragm is formed on the other thin plate. The support part which supports a part from an inner side is provided.
[0008]
As in the screw fastening structure of the thin plate of the present invention, a plate-like throttle portion having a fastening hole for a tapping screw is formed on one thin plate, and the plate-like throttle portion is supported on the other thin plate from the inside. By providing the part, the thickness of the fastening part can be substantially increased by the dish-like throttle part and the support part, and the axial force generated by the tightening torque can be supported from the inside of the dish-like throttle part by the support part. Can do. And it can prevent that a plate-shaped throttle part will be in a buckling state, and it can tighten with big tightening torque compared with the case where it penetrates into the incomplete thread part under the neck of a screw.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1. FIG.
FIG. 1 is a cross-sectional view showing a state before and after fastening of a thin plate screw fastening structure according to a first embodiment of the present invention.
[0010]
The thin plate screw fastening structure of the present embodiment is to fasten one thin plate 1 and the other thin plate 2 to each other by a tapping screw 3, and one thin plate 1 has a fastening hole 1a for the tapping screw 3 at the bottom. The other thin plate 2 has a hollow hole 2a through which the shaft portion 3a of the tapping screw 3 can be inserted at the bottom, and the thin plate 1 has the first plate-shaped throttle portion 1b. When the thin plates 2 are overlapped, a second dish-shaped diaphragm portion 2b that can be superimposed on the first dish-shaped diaphragm portion 1b on the thin plate 1 side is formed. That is, the second dish-shaped diaphragm portion 2b constitutes a support section that supports the first dish-shaped diaphragm section 1b from the inside. When the thin plate 2 is stacked on the thin plate 1, the first dish-shaped diaphragm portion 2b The inner surface of the portion 1b can come into contact with the outer surface of the second dish-like diaphragm portion 2b. Further, the peripheral edge portion 2 c of the second dish-like throttle portion 2 b is configured to be able to contact the head end surface 3 b of the tapping screw 3.
[0011]
In the screw fastening structure of the thin plate of the present embodiment having the above-described configuration, in order to fasten the thin plates 1 and 2, first, the second of the other thin plate 2 is placed on the first dish-like diaphragm portion 1 b of one thin plate 1. The plate-shaped diaphragm portion 2b is overlapped to position the fastening portion, and then the shaft portion 3a of the tapping screw 3 is inserted from the flaw hole 2a on the thin plate 2 side toward the fastening hole 1a of the thin plate 1 and tightened. As a result, as shown in the right diagram of FIG. 1, the peripheral edge 2c of the second dish-shaped diaphragm 2b overlaid on the first dish-shaped diaphragm 1b comes into contact with the head end surface 3b of the tapping screw 3, and the second dish-shaped diaphragm The bottom surface side of the part 2b is pressed against the first dish-like diaphragm part 1b to serve as a backup for the first dish-like diaphragm part 1b, supporting the axial force generated by the tightening torque from the inside of the first dish-like diaphragm part 1b, It prevents that the 1st plate-shaped aperture | diaphragm | squeeze part 1b becomes a buckled state.
[0012]
As described above, in the screw fastening structure of the thin plate of the present embodiment, the first and second dish-like throttle portions 1b and 2b can not only substantially increase the thickness of the fastening portion, but also the axial force generated by the fastening torque. Can be supported from the inside of the first dish-shaped diaphragm 1b by the second dish-shaped diaphragm 2b, and the first dish-shaped diaphragm 1b can be prevented from being buckled. For this reason, it is possible to perform the tightening with a large tightening torque as compared with the case where the incomplete threaded portion under the neck of the screw enters.
[0013]
Embodiment 2. FIG.
FIG. 2 is a cross-sectional view showing the state before and after the fastening of the thin plate screw fastening structure according to the second embodiment of the present invention, which is the same as that of the first embodiment (FIG. 1). The parts are given the same reference numerals.
[0014]
The thin plate screw fastening structure of this embodiment forms a plate-like throttle portion 1b with a fastening hole 1a similar to the first plate-like throttle portion described in the first embodiment on one thin plate 1. The other thin plate 2 is formed with a burring 2d serving as a support portion for supporting the dish-like diaphragm portion 1b from the inside.
[0015]
More specifically, the burring 2d has an inner diameter through which the shaft portion 3a of the tapping screw 3 can be inserted, and a proximal end peripheral edge portion 2e is formed so as to be in contact with the head end surface 3b of the tapping screw 3. When the other thin plate 2 is overlapped on one thin plate 1 and the fastening portion is positioned, the burring 2d is fitted into the dish-shaped restricting portion 1b and the tip 2f is tightened to the bottom of the dish-shaped restricting portion 1b. It is configured such that it is brought into contact with or in contact with the peripheral edge of the attached hole and tightened in that state.
[0016]
In the screw fastening structure of the thin plate of the present embodiment having the above configuration, in order to fasten the thin plates 1 and 2, first, the burring 2d of the other thin plate 2 is inserted into the dish-like throttle portion 1b of the one thin plate 1. Then, the fastening portion is positioned, and then the shaft portion 3a of the tapping screw 3 is inserted and tightened from the base end side of the burring 2d toward the fastening hole 1a of the thin plate 1. As a result, as shown in the right figure of FIG. 2, the front end 2f of the burring 2d fitted into the dish-like throttle part 1b is connected to the peripheral edge part of the fastening hole at the bottom of the dish-like throttle part 1b and the base end peripheral part 2e of the burring 2d. Are in contact with the head end surface 3b of the tapping screw 3, and the burring 2d is pressed against the dish-like throttle part 1b to serve as a backup for the dish-like throttle part 1b, and the axial force generated by the tightening torque is reduced to the dish-like diaphragm. It supports from the inside of the part 1b, and prevents the plate-shaped throttle part 1b from being buckled.
[0017]
Thus, in the screw fastening structure of the thin plate of this embodiment, the thickness of the fastening portion can be substantially increased by the dish-shaped throttle portion 1b and the burring 2d, and the axial force generated by the tightening torque can be increased by the burring 2d. It can be supported from the inside of the dish-like throttle part 1b, and the dish-like throttle part 1b can be prevented from being buckled. For this reason, it is possible to perform the tightening with a large tightening torque as compared with the case where the incomplete threaded portion under the neck of the screw enters.
[0018]
3 and 4 are cross-sectional views showing a thin plate screw fastening structure portion prepared as a comparative example for confirming the strength enhancement effect of the screw fastening structure portion according to each of the above-described embodiments. The same parts as those in the first and second embodiments are denoted by the same reference numerals.
[0019]
In the comparative example of FIG. 3, a burring 10d similar to the burring described in the second embodiment is formed on one thin plate 10, and the fastening portion of the other thin plate 20 remains flat, and is a screw insertion screw. In the comparative example of FIG. 4 in which only the hole 20a is formed, one thin plate 10 has a fastening hole 10a similar to the plate-shaped throttle portion with the fastening hole described in the first and second embodiments. While the plate-like diaphragm portion 10b is formed, the fastening portion of the other thin plate 20 is left flat and only the screw hole 20a for screw insertion is formed. Both comparative examples are the first and second embodiments described above. A tapping screw 3 having the same standard as that of the form is used.
[0020]
In any of the comparative examples, although the thickness of the fastening portion is secured by the burring 10d or the dish-like throttle portion 10b, the thin plate 10 itself is thin, so that the tapping screw has a large difference between the thread crest diameter and the trough diameter. When tightened with 3, the burring 10d collapsed in the comparative example of FIG. 3, and the strength could not be secured.
Moreover, in the case of the comparative example of FIG. 4, a phenomenon in which the dish-like throttle portion 10b buckles was observed.
[0021]
In the measurement results by the present inventors, when the allowable tightening torque in the comparative example of FIG. 3 having the burring 10d is used as a reference, the allowable tightening torque of the comparative example of FIG. It was confirmed that the tightening torque allowable value in each of the above-described embodiments (FIGS. 1 and 2) was about 1.35 times that value.
[0022]
【The invention's effect】
As described above, according to the present invention, a plate-like diaphragm portion having a fastening hole for a tapping screw is formed on one thin plate, and the plate-like diaphragm portion is supported on the other thin plate from the inside. Since the thickness of the fastening part can be substantially increased by the dish-like throttle part and the support part, the axial force generated by the tightening torque can be supported from the inside of the dish-like throttle part by the support part. It was possible to prevent the dish-like throttle portion from being buckled. For this reason, it was possible to perform the tightening with a large tightening torque as compared with the case where it entered the incomplete thread portion under the neck of the screw.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a state before and after fastening of a screw fastening structure for a thin plate according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a state before and after fastening of a thin plate screw fastening structure according to a second embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a state before and after screw fastening in a comparative example for confirming the strength enhancement effect according to the present invention.
FIG. 4 is a cross-sectional view showing states before and after screw fastening in another comparative example for confirming the strength enhancement effect according to the present invention.
[Explanation of symbols]
1 One thin plate, 1a Clamping hole, 1b 1st dish-shaped diaphragm part, 2 The other thin plate, 2a Flaw hole, 2b 2nd dish-shaped diaphragm part (support part), 2c 2nd dish-shaped diaphragm part Peripheral part, 2d burring (supporting part), 2e burring base peripheral part, 2f burring tip, 3 tapping screw, 3a tapping screw shaft, 3b tapping screw head end face.

Claims (3)

A thin plate screw fastening structure for fastening thin plates together with a tapping screw,
On one thin plate, while forming a dish-shaped throttle portion having a fastening hole for the tapping screw,
A thin plate screw fastening structure, wherein the other thin plate is provided with a support portion for supporting the dish-like throttle portion from the inside. A thin plate screw fastening structure for fastening thin plates together with a tapping screw,
On one thin plate, a first dish-shaped throttle portion having a fastening hole for the tapping screw is formed, and
The other thin plate has a hollow hole through which the shaft portion of the tapping screw can be inserted, and when the other thin plate is overlaid on the one thin plate, it can be overlapped with the first dish-like diaphragm portion and a peripheral portion A thin plate screw fastening structure is characterized in that a second plate-shaped restricting portion capable of contacting the head end surface of the tapping screw is formed. A thin plate screw fastening structure for fastening thin plates together with a tapping screw,
On one thin plate, while forming a dish-shaped throttle portion having a fastening hole for the tapping screw,
On the other thin plate, a burring having an inner diameter through which the shaft portion of the tapping screw can be inserted and a base end peripheral portion capable of contacting the head end surface of the tapping screw is formed,
When the other thin plate is overlaid on the one thin plate, the burring is fitted into the dish-shaped restricting portion so that the tip thereof contacts or abuts the peripheral edge of the fastening hole at the bottom of the dish-shaped restricting portion. A thin plate screw fastening structure characterized by being set to.

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