JP2004154802A - Forming method for integral type female screw part in press forming article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure strength of a female screw part which is integrally formed with a panel raw material without increasing thickness of the panel raw material to be press-worked. <P>SOLUTION: A forming method for the integral type female screw part forms the integral type female screw part integrated with a panel raw material 10 by press-working of the panel raw material 10 in a press-formed product. Compression workings are repeated in respective width and height directions of a cylindrical part 14 formed by drawing processing of the panel raw material 10. Thus, a wall of cylindrical part 14 is increased and then threading processing is executed to an inner periphery of the cylindrical part 14. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for forming a female screw portion integrated with a panel material such as a steel plate by press working on the panel material.
[0002]
[Prior art]
Conventionally, a nut is welded to a metal bracket, for example, when another component is fixed to the metal bracket with bolts. On the other hand, for the purpose of reducing the number of parts, burring (pressing by pressing) is performed on the bracket, and threading (tapping) is performed on the inner periphery of the cylindrical part formed by this. There is also proposed a technique of integrally molding a bracket with a bracket.
A technique for integrally joining two parts by burring is disclosed in Non-Patent Document 1, for example.
[0003]
[Non-patent document 1]
http: // www. ai-link. ne. jp / free / products / kanagata / kakoujohou / Br / br. htm
[0004]
[Problems to be solved by the invention]
In the conventional technology, the wall thickness of the cylindrical portion forming the female screw portion is the same as the thickness of the bracket, or becomes thinner than the thickness of the bracket depending on the drawing depth at the time of burring, and the strength of the female screw portion is reduced. Low, and inferior in fastening strength. Increasing the thickness of the bracket in order to secure the strength of the female screw portion leads to an increase in cost and weight.
An object of the present invention is to solve the conventional problems, and an object of the present invention is to secure the strength of a female screw portion formed integrally with a panel material without increasing the thickness of the panel material to be pressed. That is.
[0005]
[Means for Solving the Problems]
The present invention is to achieve the above object, and the invention according to claim 1 is a press-formed product for forming a female screw portion integrated with the panel material by pressing the panel material. A method of forming an integrated female screw portion, wherein a cylindrical portion formed by drawing a panel material is repeatedly subjected to compression processing in each of its radial direction and height direction to form a wall of the cylindrical portion. After the wall thickness is increased, the inner periphery of the cylindrical portion is subjected to thread cutting.
Thereby, the strength of the female screw portion can be sufficiently secured and the fastening force with the bolt or the like can be maintained without increasing the thickness of the panel material.
[0006]
According to a second aspect of the present invention, there is provided a method for forming an integrated female screw portion in a press-formed product according to the first aspect, wherein in the drawing of a panel material, a cylindrical portion formed by the drawing is formed. The corners of the drawing tip and the root are formed at substantially right angles.
Thus, buckling of the cylindrical portion and escape of the material due to the compression processing in the next step can be prevented, and the wall thickness can be effectively increased.
[0007]
According to a third aspect of the present invention, there is provided a method of forming an integrated female screw portion in a press-formed product according to the first aspect, wherein in the drawing of a panel material, a cylindrical portion formed by the drawing is formed. At least the drawing depth is set so that the wall is maintained at a thickness substantially equal to the thickness of the panel material.
Thereby, the wall thickness of the wall of the cylindrical portion in the compression processing is efficiently performed.
[0008]
According to a fourth aspect of the present invention, there is provided a method for forming an integral female screw portion in a press-formed product according to the first aspect, wherein the compression of a cylindrical portion formed by drawing is performed at the root of the cylindrical portion. The part is compressed into a tapered shape.
By compressing the root portion of the cylindrical portion into a tapered shape in this manner, the strength of the finally formed female screw portion is further increased.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
FIG. 1 to FIG. 4 are explanatory views showing a forming process of an integrated female screw portion in a press-formed product in relation to a plane and a cross section. In these drawings, the serial numbers of P1 to P36 described for each step are step (process) numbers. In the present embodiment, a strip-shaped steel plate wound into a roll is used as the panel material 10 to be subjected to press forming. Processed products (hereinafter, also referred to as workpieces) in each step are connected without being cut off individually during processing.
[0010]
Steps P1 to P3 shown in FIG. 1 are punching steps of the work outer shape. However, the punching is actually performed only in any one of the processes P1 to P3. The other steps and step P4 are idle (idle) sections to avoid interference with adjacent processing equipment. Steps P5 to P14 shown in FIGS. 1 and 2 are drawing steps for forming an integrated female screw portion, and are set to a total of 10 steps. In addition, the subsequent processing including the drawing processing is performed at two places for one work.
[0011]
FIG. 5 is a cross-sectional view illustrating the shape of the work processed in the first step P5 of the drawing. FIG. 6 is a cross-sectional view illustrating the shape of the workpiece processed in the last step P14 of the drawing. The narrowed portion 12 in the work shape shown in FIG. 5 is the first one to become the bottomed cylindrical portion 14 shown in FIG. 6, and the thickness of the cylindrical portion 14 is not thinner than the thickness of the panel material 10. The shape of the narrowing portion 12, that is, the outer diameter D1 and the narrowing depth H1 are set. Incidentally, the thickness of the panel material 10 is about 1.2 mm, the outer diameter D1 is about 46 mm, and the drawing depth H1 is about 20 mm.
[0012]
The bottomed cylindrical portion 14 shown in FIG. 6 is formed in a shape that can appropriately perform compression processing in the next step. In other words, the drawing depth H2 of the cylindrical portion 14 is the same as the drawing depth H1 of the narrowing portion 12, but the outer diameter D2 of the cylindrical portion 14 is narrowed sufficiently smaller than the outer diameter D1 of the narrowing portion 12. Incidentally, the outer diameter D2 is about 16.5 mm. Also, the angles of the corners at the narrowed end portion 14a and the root portion 14b of the cylindrical portion 14 are set to be substantially right angles. Thereby, it is possible to prevent the buckling of the cylindrical portion 14 and the escape of the material due to the compression processing. Ideally, the cylindrical portion 14 is formed by a single drawing process. However, in reality, it is impossible to form the cylindrical portion 14, so that the processing is performed in all 10 steps.
[0013]
In a step P15 shown in FIG. 2, the bottom plate of the drawing tip portion 14a of the cylindrical portion 14 is punched. Steps P16 to P24 shown in FIGS. 2 and 3 are compression steps for forming the integrated female screw portion. FIG. 7 is a cross-sectional view illustrating the shape of the work processed in the first step P16 of the compression processing. The cylindrical portion 14 in this work shape is compressed in each of the radial direction and the height direction (drawing depth direction), and the corner shape of the root portion 14b of the cylindrical portion 14 is determined by this processing. Incidentally, the outer diameter D3 is about 14.4 mm, and the height (drawing depth) H3 is about 17.5 mm.
[0014]
FIG. 8 is a cross-sectional view illustrating the shape of the workpiece processed in the compression processing step P20. By this processing, the cylindrical portion 14 is further compressed in the radial direction and the height direction, and the wall of the cylindrical portion 14 is thickened. Further, by forming the root portion 14b of the cylindrical portion 14 in a tapered shape, the strength is increased by a synergistic effect with the wall thickness increase. The outer diameter D4 and height H4 of the cylindrical portion 14 in FIG. 8 are both about 12 mm.
[0015]
FIG. 9 is a cross-sectional view illustrating the shape of the work processed in the compression processing step P24. In this step P24, the cylindrical portion 14 is further compressed, and is processed into a shape optimal for threading (tapping) in the next step. The outer diameter D5 of the cylindrical portion 14 in FIG. 9 is about 10.6 mm, and the height H5 is about 10 mm.
[0016]
Steps P26 to P29 shown in FIGS. 3 and 4 are thread cutting steps for the inner hole of the cylindrical portion 14. FIG. 10 is a cross-sectional view illustrating the shape of the workpiece after the thread cutting process. The threaded portion 14 c is formed in the inner hole of the cylindrical portion 14. As described above, since there are two cylindrical portions 14 serving as female screw portions of the press-formed product for one work, threading processing for these cylindrical portions 14 is individually performed in steps P27 and P29. I have. The process P28 is a play (idle) for avoiding interference between the two tapping facilities. Therefore, if the tapping equipment is reduced in size, or if there is equipment capable of simultaneously performing thread cutting at two locations, the steps P26 to P29 can be reduced to one step.
[0017]
When the process P29 shown in FIG. 4 has passed, the forming of the female screw portion integrated with the panel material 10 is completed. After that, the outer periphery of the work is trimmed in a step P31 in FIG. FIG. 11 is a cross-sectional view illustrating a work shape after the bend processing. As shown in this drawing, a bend 10a having a rise of about 5 mm is formed on the shear edge portion of the panel material 10.
[0018]
In this manner, by increasing the wall thickness of the cylindrical portion 14 and then forming the female screw portion by processing the screw portion 14c, the strength of the female screw portion can be increased without increasing the thickness of the panel material 10. it can. In the compression process for increasing the thickness of the wall of the cylindrical portion 14, the root portion 14b of the cylindrical portion 14 is formed into a tapered shape as shown in FIG. Strength is further increased.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a forming process of an integrated female screw portion in a press-formed product. FIG. 2 is an explanatory diagram showing a forming process of an integrated female screw portion in a press-formed product. FIG. 4 is an explanatory view showing a forming process of an integrated female screw portion. FIG. 4 is an explanatory diagram showing a forming process of an integrated female screw portion in a press-formed product. FIG. 5 is a work shape processed in a first process of drawing. FIG. 6 is a cross-sectional view showing the shape of a workpiece processed in the last step of drawing. FIG. 7 is a cross-sectional view showing the shape of a workpiece processed in the first step of compression. FIG. 9 is a cross-sectional view showing the shape of the work after the thickness increase processing of the compression processing. FIG. 9 is a cross-sectional view showing the shape of the work processed in the final step of the compression processing. FIG. 11 shows the shape of the workpiece after bend processing. Rear view DESCRIPTION OF SYMBOLS
10 Panel material 14 Cylindrical part 14a Tip part 14b Root part 14c Screw part

Claims (4)

A method for forming a female screw portion integrated with the panel material by pressing the panel material, wherein the cylindrical portion formed by drawing the panel material has a radial direction and a height. A method for forming an integrated female screw portion in a press-formed product, wherein after increasing the wall thickness of a cylindrical portion by repeating compression processing in each of the directions, threading is performed on the inner periphery of the cylindrical portion. A method for forming an integrated female screw portion in a press-formed product according to claim 1, wherein, in drawing of a panel material, a corner of a drawing tip portion and a root portion of a cylindrical portion formed by the drawing process is formed. A method for forming an integral female screw portion in a press-formed product, wherein the integrated female screw portion is formed substantially at right angles. A method for forming an integrated female screw portion in a press-formed product according to claim 1, wherein, in the drawing of the panel material, the wall of the cylindrical portion formed by the drawing is substantially equal to the thickness of the panel material. A method of forming an integrated female screw portion in a press-formed product, wherein at least a drawing depth is set so as to maintain an equal plate thickness. 2. A method for forming an integrated female screw portion in a press-formed product according to claim 1, wherein, in the compression processing on the cylindrical portion formed by drawing, the root portion of the cylindrical portion is compressed into a tapered shape. A method for forming an integral female screw portion in a press-formed product, characterized by the following.

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