JP2002066743A - Stud welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stud welding method that provides high accuracy in positioning a stud, the stud having a thread or other type of fastening means, without necessity of a positioning device of high accuracy. SOLUTION: The welding method that welds the stud to a work consists of a step that welds a stud blank 1 to the work 6, and a step that processes the welded stud blank to form a necessary stud shape such as a female-threaded stud.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stud welding method and, more particularly, to a method for welding a screw stud or another stud to a member to be welded.

[0002]

2. Description of the Related Art Welding screw studs such as bolt studs and nut studs to a member to be welded such as a panel has already been performed. For example, a screw stud is welded to a body panel of an automobile, and the welded screw stud is used to fix other parts to the body panel. Since the screw stud is fixed to the member to be welded, there is no need to support the screw member, and there is an advantage that the work of attaching parts is made easier and more reliable.

[0003]

In such welding of the screw stud, if the welding position is shifted, the mounting position of the component is shifted or the component cannot be mounted, so that the positional accuracy of the screw stud is reduced. It must be kept high. For this reason, a high-precision welding positioning device is required for the welding device, which makes the welding device expensive and requires skill in the welding operation. Further, in the case of a screw stud having a complicated shape, it is difficult to perform welding while maintaining high-precision positioning.

Accordingly, an object of the present invention is to provide a stud machining method capable of increasing the accuracy of a welding position in a screw stud or another stud without requiring a high-precision positioning device.

[0005]

In order to achieve the above object, a method for welding a stud to a member to be welded according to the present invention comprises the steps of welding a blank for a stud to the member to be welded; Machining the application blank into a predetermined stud shape. Here, the stud blank refers to a semi-finished product before it is completed into a predetermined target stud. In this way, after the stud blank (semi-finished product) is welded, it is finished as a stud, so it can be processed so as to correct the stud misalignment during the processing, and a high-precision positioning device is provided. The accuracy of the welding position can be increased without the need.

In the present invention, the stud blank is
A welding surface to the member to be welded, formed so as to have a rod-shaped main body portion capable of forming a female screw, the welding surface is fixed to the member to be welded in a welding step, and a female screw is formed in the body portion in a processing step. Can be machined into female thread studs. In this case, a pilot hole for processing a female screw may be formed in advance in the main body of the blank. Also,
In the present invention, the stud blank is formed so as to include a surface to be welded to the member to be welded, and a rod-shaped main body capable of forming an external thread, and the welding surface is fixed to the member to be welded in the welding step. An external thread having a predetermined outer diameter can be formed on the main body and processed into an external thread stud. In this case, at least one part of the main body of the blank may have a rod-shaped portion having an outer diameter close to the outer diameter of the male screw portion, and the rod-shaped portion may be threaded in the processing step. Then, the blank may be entirely formed of a rod-shaped body having an outer diameter close to the outer diameter of the male screw portion. Further, in the present invention, the stud blank is formed of a plate-like body having a constant thickness, one end surface of which is used as a welding surface to the member to be welded, and the welding surface is fixed to the member to be welded in the welding step. Then, a hole for attaching another component or the like may be formed in the plate-like body in the processing step.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. The method of welding a stud to a workpiece to be welded comprises the steps of welding a stud blank to a workpiece and processing the welded stud blank into a predetermined stud. FIG. 1 shows a stud blank 1 before welding. The blank is generally called a semi-finished product and is a product before being processed into a final product. The stud blank 1 in FIG. 1 is a semi-finished product before being completed to a predetermined target stud. is there. The illustrated stud blank 1 has a conical welding surface 2 on the lower surface and a cylindrical rod-shaped main body 3 above the welding surface 2.
And The upper surface of the main body 3 is a processing surface 5 for processing a female screw or a male screw. The material of this blank 1 may be made entirely of a weldable metal, at least the welding surface 2 being made of a weldable metal, and the other part, namely the body 3, fixed to the welding surface. Other easy materials may be used. Further, the main body 3 may have a columnar shape or a prismatic shape as long as it is a rod-shaped body.

In the present invention, a blank 1 for a stud is used.
Is held by a collet (not shown) of a stud welding machine and is welded to a predetermined position of a member to be welded such as a body panel of an automobile. The stud welding machine may be of a structure in which, for example, a stud welding machine is attached to a robot arm installed on an automobile assembly line, and a stud blank 1 is automatically fed one by one to a tip of a collet. It may be a stud welding machine. In the present invention, the stud blank 1 fixed to a predetermined position of the member to be welded by welding is processed into a predetermined final shape in the fixed state. In the embodiment of FIG. 2, the screw member 9 is welded to the member 6 to be welded at a portion 7, and a threading tool (not shown) is positioned at a predetermined position on the processing surface 5 of the main body 3, and a screw hole 9 is formed. You. That is, the blank 1 is processed as a female screw stud (nut stud) while being welded to the member 6 to be welded. When working on the internal thread stud,
The internal thread position can be machined to correct the stud misalignment, thereby increasing the stud position accuracy without the need for a high precision positioning device. The diameter of the screw and the length of the screw can be arbitrarily set according to the design. Furthermore, in the processing step of the stud blank 1 after welding, not only the formation of the screw hole 9 but also the entire outer diameter and the shape of the female screw stud, the height from the member to be welded is determined, and the stud is formed. You may process so that an angle may be determined. Thus, in the processing step, the stud blank can be formed into any desired final shape.

FIG. 3 shows another example of a blank for a female thread stud. In the female thread stud blank 10, a pilot hole 11 is formed to facilitate forming a female thread. The diameter of the pilot hole 11 is formed smaller than the screw hole 9 for the female screw in FIG. When a screw hole is formed in the blank 10 after welding, since the pilot hole 11 is formed, the screw hole can be easily formed.

FIG. 4 shows an embodiment in which the stud blank 1 of FIG. 1 is welded to a member 6 to be welded and then processed into a male screw stud 13. In the embodiment of FIG. 4, the stud blank 1 is welded to the member 6 to be welded at a portion 7. Thereafter, a cutting tool (not shown) for forming the male screw portion 14 is installed in the main body portion 3, and a rod-shaped portion for the male screw portion is cut from the main body portion 3. Thereby, the blank comes to have the flange 15 and the bar portion for the male screw portion. Then, a threading tool (not shown) is positioned at a predetermined position on the rod portion, and the male screw 17 is formed on the rod portion. That is, the blank 1 is processed as a male thread stud (bolt stud) in which the male screw portion 14 protrudes from the member 6 while being welded to the member 6 to be welded. When working on this external thread stud,
The position of the bar portion for the male screw portion can be machined so as to correct the positional deviation of the stud, thereby increasing the accuracy of the stud position without requiring a high-precision positioning device. The diameter of the screw and the length of the screw can be arbitrarily set according to the design. Furthermore, in the processing step of the stud blank 1 after welding, not only the formation of the external thread portion 14 but also the diameter and height of the flange 15 can be arbitrarily determined, and the overall outer diameter and the shape of the external thread stud It can be processed as follows. In this way, even with external thread studs, any desired final shape can be formed from the stud blank in the processing step.

FIG. 5 shows another example of a blank for a male screw stud. In the blank 18 for a male screw stud, a rod-like portion 19 for a male screw portion and a flange 21 are formed in advance. In addition, a welding surface 20 is formed on the lower surface of the flange 21. The outer diameter of the rod-shaped portion 19 is preferably formed to be larger than the outer diameter of the male screw portion 14 in FIG. The use of the blank 18 eliminates the necessity of cutting the rod portion and the flange for the external thread portion, simplifies the machining after welding of the blank, and shortens the machining time.

FIG. 6 shows still another example of the blank for the external thread stud. Blank 2 for this male thread stud
In 2, a rod 23 for a male screw portion and a small-diameter weld 25 are formed in advance. However, no flange is formed. Also in the case of the blank 22, it is preferable that the outer diameter of the rod-shaped portion 25 is formed larger than the outer diameter of the male screw portion 14 in FIG. In addition, the cutting process of the rod portion for the external thread portion and the flange is not required, the working after welding of the blank is simplified, and the working time is shortened.

FIG. 7 shows a locking stud 26 obtained by welding a stud blank to a member 6 to be welded according to still another embodiment. The locking stud 26 in FIG. 7 has a constant thickness. Molded from a stud blank formed as a plate-like body having In the illustrated example, the blank is formed as a substantially rectangular plate-like body having a constant thickness, and one end surface of the blank serves as a welding surface to the member to be welded. In the welding step, the welding surface is fixed at a predetermined position of the member 6 to be welded at the portion 27. In the processing step, a hole 29 for mounting another component or the like is formed in the plate blank. The position, size and shape of this hole can be arbitrarily determined as required.

[0014]

According to the present invention, a stud blank (semi-finished product) is welded and then finished as a stud, so that the stud can be misaligned during the processing. The accuracy of the welding position can be increased without the need for a high-precision positioning device. Also,
Since the stud blank is welded after the formation of the member to be welded, it is not necessary to integrally form the member to be welded and the stud, and a forging or press mold for that purpose is not required.
And when obtaining a screw stud, the screw length, the outer diameter of the female screw stud, the outer diameter and length of the male screw stud column, and even the shape can be arbitrarily formed in a blank shape, and the strength and shape according to the application are can get.

[Brief description of the drawings]

FIG. 1 is a perspective view of a blank for a female screw or a male screw stud used in the present invention.

FIG. 2 is a perspective view of the female screw stud after the stud blank of FIG. 1 is welded and processed.

FIG. 3 is a perspective view of another embodiment of a female thread stud blank used in the present invention.

FIG. 4 is a perspective view of the external thread stud after the stud blank of FIG. 1 is welded and processed.

FIG. 5 is a perspective view of another embodiment of a blank for external thread studs used in the present invention.

FIG. 6 is a perspective view of still another embodiment of a blank for external thread studs used in the present invention.

FIG. 7 is a perspective view showing a state in which a locking stud composed of a plate-shaped blank is fixed to a member to be welded according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stud blank 2 Weld surface 3 Main part 5 Work surface 6 Workpiece 9 Screw hole 10 Female screw stud blank 11 Pilot hole 13 Male screw stud 14 Male screw part 15 Flange 17 Male screw 18 Male screw stud blank 19 Rod part 20 Weld surface 21 Flange 22 Male screw stud blank 23 Bar-shaped part 25 Welded part 26 Lock stud 29 Lock hole

Claims (7)

[Claims] 1. A method for welding a stud to a member to be welded, comprising the steps of: welding a stud blank to the member to be welded; and processing the welded stud blank into a predetermined stud shape. A stud welding method characterized by comprising: 2. The stud welding method according to claim 1, wherein the stud blank includes a surface to be welded to a member to be welded, and a rod-shaped main body capable of forming an internal thread, and the welding surface is provided in the welding step. Is fixed to a member to be welded, and a female screw is formed in the main body portion in the processing step to form a female screw stud. 3. The stud welding method according to claim 2, wherein said body portion of said blank is pre-formed with a pilot hole for machining a female screw. 4. The stud welding method according to claim 1, wherein the stud blank includes a surface to be welded to a member to be welded, and a rod-shaped main body capable of forming a male screw, and the welding surface in the welding step. Is fixed to a member to be welded, and in the machining step, a male thread portion having a predetermined outer diameter is formed in the main body portion to be machined into a male thread stud. 5. The stud welding method according to claim 4, wherein at least a part of the main body of the blank has a rod-shaped portion having an outer diameter close to the outer diameter of the male screw portion, and the rod-shaped portion is formed in the machining step. A method comprising threading a body part. 6. The stud welding method according to claim 5, wherein the entire body of the blank is formed of a rod having an outer diameter close to the outer diameter of the external thread. Method. 7. The stud welding method according to claim 1, wherein the stud blank is formed of a plate-like body having a constant thickness, and one end face of the blank is a welding surface to a member to be welded. And fixing the welding surface to the member to be welded in the welding step, and forming a hole for attaching another component or the like to the plate-like body in the processing step.