JPH09225578A - Blank for stud bolt and manufacture of stud bolt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a blank for stud bolt and the stud bolt having a high yield and a high productivity without damage to a projecting part for welding. SOLUTION: The projecting part 1 for welding is projected at the center of upper end surface of a shaft part 2 and a reverse-shade type flange part 3 protected by surrounding the projecting part 1 for welding is formed in the upper end peripheral edge of the shaft part 2. The shaft part 2 of the blank for stud bolt forming the projecting part 1 for welding and the reverse-shade flange part 3 at the upper end of the shaft part 2 is interposed between a moving side die and a fixing side die in a screw rolling-form die for forming a reverse-tapered surface upward to the rolling-form end part at the upper end surface. The seat surface of the reverse-shade flange part 3 in the blank for stud bolt is positioned on the tapered surface of the screw rolling-form die to execute the screw rolling-form, and the screw is engraved to the shaft part 2 and the reverse-shade flange part 3 is pushed upward by the tapered surface and broken and separated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for a stud bolt used for manufacturing a stud bolt which is welded to a base material such as a steel plate and stands upright, and a method for manufacturing the stud bolt.

[0002]

2. Description of the Related Art Conventionally, as a material for a stud bolt for manufacturing a stud bolt which is welded to a base material such as a steel plate and stands upright, as shown in FIG. The welding projection 31 having a diameter of 0.5 mm and a height of 0.5 mm was forged. Since this forging has a high forging ratio, the one having the large-diameter flange portion 32 formed was used. To manufacture a stud bolt from such a stud bolt material, first, the flange portion 32 of the stud bolt material is cut by a lathe or the like so that the outer diameter of the flange portion 32 becomes substantially the same as the screw outer diameter. To process. After that, the stud bolt material with the flange portion 32 cut is fed into the thread rolling die to form the shaft portion 30.
It was customary to roll a screw on. However, when the material for the stud bolt is supplied, the welding projection 31 of the material for the stud bolt may collide with a positioning stopper or another object to be deformed. If the welding projections 31 of the stud bolt are deformed, the pilot arc does not fly normally during welding of the stud bolt, and there is a problem that welding failure of the stud bolt occurs. Further, when manufacturing the stud bolts, it is necessary to cut the flange portion 32 with a lathe or the like and then convey the material for the stud bolts to a thread rolling die in a separate process, so that the manufacturing process increases and the manufacturing system becomes larger. In addition, there was a problem of poor productivity.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a material for a stud bolt and a stud bolt which are highly productive and have a high yield without damaging the welding projections and can simplify the manufacturing process. It is intended to provide the law.

[0004]

In order to achieve the above-mentioned object, an inverted shade for projecting a welding projection at the center of the upper end surface of the shaft portion and surrounding and protecting the welding projection at a height higher than the welding projection. A material for a stud bolt, characterized in that a flanged portion is formed on the upper peripheral edge of the shaft portion, is defined as the invention of claim 1, and a thread rolling die in which a taper surface that faces upward toward the rolling end is formed on the upper end surface. Between the moving side die and the fixed side die of
The shaft portion of the material for stud bolts is sandwiched at the upper end of the shaft portion, and the shaft portion of the material for stud bolts is sandwiched, and the shaft portion of the material for stud bolts is sandwiched. The thread surface is located on the taper surface of the thread rolling die, and the thread is rolled, the shaft is engraved with a screw, and the taper surface pushes up the inverted cap-shaped collar portion upwards to separate it. A method of manufacturing a stud bolt, characterized by the above, is the invention of claim 2.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a preferred embodiment of a material for a stud bolt of the present invention will be described in detail with reference to FIG. Reference numeral 1 denotes a welding projection that projects from the center of the upper end surface of the shaft portion 2. The welding projection 1 has a diameter of 0.5 mm and a height of 0.5 mm. Denoted at 3 is an inverted cap-shaped brim portion formed around the upper end of the shaft portion 2 so as to surround the welding projection 1, and the height of the inverted cap-shaped brim portion 3 is slightly higher than the height of the welding projection 2. During the thread rolling, positioning by the stopper, and when supplying to the thread rolling die, the welding projection 1
Protects the object from being deformed by hitting other objects. Further, the welding projection 1 and the inverted cap-shaped brim portion 3 are formed by forging, and the base of the inverted umbrella-shaped brim portion 3 is a thin portion 3a so that the inverted cap-shaped brim portion 3 is easily broken and separated from the shaft portion 2. There is. Reference numeral 4 is a chamfered portion at the base end of the shaft portion 2.

In such a structure, the inverted cap-shaped collar portion 3 is locked on the upper surface of a slit-shaped supply chute (not shown), and the material for the stud bolt is suspended in a state in which the upper and lower sides are regulated. After being conveyed to a forming die and positioned by the upper and lower positioning stoppers S, a screw is roll-engraved on the peripheral surface of the shaft portion 2, and the inverted cap-shaped flange portion 3 is fractured and separated at the time of screw rolling. Stud bolts.

Next, a preferred embodiment of the stud bolt manufacturing method of the present invention will be described in detail with reference to FIGS. Reference numeral 10 denotes a thread rolling die including a moving side die 11 and a fixed side die 12, and a rolling blade 11a and a rolling blade 12a are provided on the facing surfaces of the moving side die 11 and the fixed side die 12 of the thread rolling die 10. Are formed. Further, the upper end surface of the moving-side die 11 is one in which a high-flat portion 15 is formed in the rear portion via a taper surface 14 that is upward from the low-flat portion 13 in the front portion toward the rolling end. The upper end surface is formed by forming a high flat portion 18 in the rear portion from a low flat portion 16 in the front portion through a taper surface 17 that is directed upward toward the rolling end, and the edges of the tapered surfaces 14 and 17 are inverted shades. This is for abutting against the seating surface of the flanged portion 3 to break and separate the inverted hat-shaped flanged portion 3.

In the structure thus constructed, the welding projection 1 is projected at the center of the upper end surface of the shaft portion 2, and the inverted cap-like flange portion 3 for surrounding and protecting the welding projection 1 is provided on the shaft portion 2. The material for stud bolts formed on the upper edge is conveyed to the thread rolling die 10 in a suspended state in which the upper and lower sides are regulated in a state where the inverted cap-shaped collar portion 3 is locked to the upper surface of a supply chute (not shown). The material for the stud bolt is positioned by the stopper S that regulates the upper end surface of the inverted hat-shaped collar portion 3.
Then, the stud bolt material is sandwiched between the rolling start ends of the rolling blades 11a, 12a of the moving side die 11 and the fixed side die 12, and then the moving side die 11 is slid forward so that the rolling blades 11a, 12a As a result, a screw is formed on the outer peripheral surface of the shaft portion 2. However, in the initial stage of thread rolling, the bearing surface of the inverted cap-shaped collar portion 3 of the material for the stud bolt is arranged in a state of being close to the low flat portion 13 of the moving side die 11 and the low flat portion 16 of the fixed side die 12. As the thread rolling progresses, the taper surface 1 that faces upward toward the rolling end of the moving side die 11 and the fixed side die 12 is formed.
4, the inverted hat-shaped brim portion 3 is successively pulled upward, and finally separated from the thin portion 3a by fracture as shown in FIG. Then, as shown in FIG. 4, the stud bolt having the welding projection 1 protruding from the upper end surface is manufactured.

[0009]

As is apparent from the above description, the material for a stud bolt of the present invention has a reverse umbrella-like collar portion formed around the welding projection to protect the welding projection. The welding projection does not come into contact with the positioning stopper during manufacturing, and when supplying the material for the stud bolt to the thread rolling die, the welding projection does not collide with other objects and become defective. Therefore, the yield is good, and it is possible to reliably prevent defective welding of the stud bolt. Further, since the upside down of the material for stud bolts is restricted by the inverted cap-shaped flange portion, a device for discriminating upside down is not required, and the stud bolt material supply device can be made inexpensive. Also,
The manufacturing method of the stud bolt of the present invention is performed by using a material for a stud bolt having an inverted cap-shaped flange portion, a moving die or a fixed side having a tapered surface for locking the seat surface of the inverted cap-shaped collar portion formed on the upper end surface. Since thread rolling is performed with a die, it is possible to fracture and separate the inverted cap-shaped collar portion at the same time as thread rolling.
Since there is no need to cut the flange portion by a conventional lathe, the manufacturing process can be reduced, and various advantages such as efficient and inexpensive mass production of stud bolts can be obtained. Therefore, the present invention greatly contributes to the development of the industry as a material for stud bolts and a method of manufacturing stud bolts that solves the conventional problems.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing a preferred embodiment of a material for a stud bolt of the present invention.

FIG. 2 is a perspective view showing a thread rolling die used in the method for manufacturing a stud bolt according to the present invention.

FIG. 3 is an explanatory view showing a manufacturing process of a stud bolt by a thread rolling die.

FIG. 4 is a front view of a stud bolt manufactured according to the present invention.

FIG. 5 is a front view showing a conventional material for a stud bolt.

[Explanation of symbols]

 1 Welding protrusion 2 Shaft part 3 Reverse cap-shaped collar part 10 Thread rolling die 11 Moving side die 12 Fixed side die 14 Tapered surface 17 Tapered surface

Claims (2)

[Claims] 1. An inverted cap-shaped collar portion, which is higher than the welding protrusion and surrounds and protects the periphery, is formed on the upper end peripheral edge of the shaft portion while projecting the welding protrusion at the center of the upper end surface of the shaft portion. Material for stud bolts characterized by. 2. A welding projection and a welding projection at the upper end of a shaft portion between a moving die and a fixed die of a thread rolling die having an upper end surface having a taper surface facing upward toward the rolling end. The shaft part of the material for stud bolts, which has an inverted cap-shaped collar that is higher than the surroundings, is sandwiched, and the seat surface of the inverted cap-shaped collar of the material for stud bolts is on the taper surface of the thread rolling die. A method for manufacturing a stud bolt, characterized in that a thread is formed on the shaft by engraving a screw on the shaft, and the taper surface pushes the inverted cap-shaped collar upward to separate the stud bolt.