JPH0258032B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gap type stud welding device.

Gap-type stud welding equipment forms a gap between the stud and the base metal during welding, and applies welding voltage to pressure the stud to the base metal and weld it. The welding is done in a timely manner.

Conventional gap-type stud welding equipment creates a gap between the stud and the base metal, so it is necessary to manually pull the stud and the collet that holds the stud backward from the nose tip before welding. . The raised stud and collet are held in their retracted position by the device's mechanical latch or magnet, and when the trigger is pulled, the welding voltage is applied between the base metal of the stud and the stud is removed. A large current momentarily flows through the base metal, and the stud is welded to the base metal.

The stud welding apparatus described above has the drawback that it is necessary to pull up the stud and collet before welding, which takes time and effort, and also places a burden on the operator. Furthermore, since the stud is aligned with the welding position on the base metal in a pulled-up state, accurate alignment is difficult. That is, it is difficult to center the tip of the nose of the device. Furthermore, the pulling operation may be forgotten, resulting in defective welding.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a gap-type stud welding device that eliminates the need for manual operations for pulling up studs and allows accurate positioning.

In order to achieve this objective, according to the present invention,
The collet is equipped with a collet capable of holding a stud at its tip and a nose that extends toward the tip so as to surround this collet. During welding, the collet holds the tip of the stud by pulling it up to a predetermined height above the tip of the nose. and a stud welding device that creates a gap between the base materials, including at least a spring that pushes the collet toward the tip and urges the tip of the stud to protrude from the tip of the nose; A rod-shaped member whose rear end is made of a magnetic material, and which is arranged adjacent to the rear end of this rod-shaped member and acts to raise the stud held in the collet together with the rod-shaped member to the predetermined height when excited. By operating a lift coil and a trigger on the device main body, the lift coil is energized to lift the stud to the predetermined height from the base metal to form a predetermined gap, and then a welding voltage is applied between the stud and the base metal, and a control circuit operative to thereafter demagnetize the lift coil.

Due to this feature, even with a gap type stud welding device, there is no need for any manual operation to pull up the stud and collet, which not only saves labor and time, but also eliminates welding defects caused by forgetting to pull up the stud. Moreover, until you pull the trigger,
Since the tip of the stud protrudes from the tip of the nose, there is an advantage that alignment to the welding position of the base metal can be easily and accurately performed.

In an embodiment of the present invention, a spring is provided between the rod-shaped member and the main body of the device, and the control circuit is configured to generate a first pulse of a predetermined width for excitation of the lift coil by a trigger signal from a trigger. a pulse generating circuit that generates a second pulse for applying a welding voltage between the stud and the base metal after a predetermined time elapses after the rise of the first pulse; and a pulse generating circuit that receives the first pulse and supplies an exciting current to the lift coil. Preferably, the welding power source includes a lift coil power source and a welding power source that receives the second pulse and applies a welding voltage between the stud and the base metal.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a substantially pistol-shaped stud welding tool 1 is shown on the right. This tool 1
is equipped with a grip 2 and a main body 3, and the grip 2 has a trigger 4.
is provided. The main body 3 is provided with a collet 5 that can hold the stud S at the tip, and a nose 6 made of a hollow sleeve that extends toward the tip so as to surround the collet 5. By simply bringing the stud into contact with the base material, the length at which the stud is pulled up from the base metal can be maintained constant at all times, and since the welded part of the stud is surrounded by the nose, spatter that occurs during welding can be prevented from scattering. A shielding gas atmosphere can also be formed by filling with shielding gas. A spindle 7 made of a rod-shaped member is fixed to the rear end of the collet 5, and the collet 5 and the spindle 7 are attached to the main body 3 so as to be movable in the axial direction. For this purpose, the main body 3 is provided with two reduced diameter portions 8, 9 forming a bore with an inner diameter equal to or slightly larger than the diameter of the spindle 7.

A shoulder portion 10 is formed on the spindle 7, and the main body 3
A coil spring 11 is provided between the reduced diameter portion 9 and the
As a result, the spindle 7 is pushed in the distal direction together with the collet 5. In order to adjust the compressive force of the spring 11, the reduced diameter portion 9 may be configured to be able to change its position back and forth. Stud S
is held with respect to the collet 5 with its head protruding from the tip of the nose 6. The shoulder portion 10 of the spindle 7 also acts to restrict the amount of protrusion of the stud S. A stop pin 14 is provided inside the collet 5, and its position may be changed depending on the length of the stud S.

Further, an armature 15 serving as an armature is attached to the rear end of the spindle 7, and a lift coil 12 is provided adjacent to the armature 15. This lift coil 12 is connected to the spindle 7
When a current is passed through the coil 12, a magnetic field is generated that magnetically attracts the armature 15. For this reason, armature 1
5 is made of a magnetic material. It should be noted that the armature 15 and the spindle 7 may be formed integrally rather than separately, and of course, in this case, the entire spindle may be made of a magnetic material. A shoulder portion 13 is provided at the rear end of the armature 15, and a shoulder portion 13 is provided at the rear end of the armature 15.
The lifting height is regulated. Also, this shoulder part 1
The position of 3 may be changed according to the length of the stud S.

In FIG. 1, on the left side, a circuit 20 is shown which controls the operation of the stud welding tool. This control circuit 20 receives a trigger signal from the trigger 4, generates a first pulse of a predetermined width to excite the lift coil 12 using this signal, and then generates a first pulse of a predetermined width.
A pulse generating circuit 21 that generates a second pulse for applying a welding voltage that rises after a predetermined time has elapsed after the pulse rises, and a lift coil that receives the first pulse and supplies an exciting current to the lift coil 12. and a welding power supply circuit 23 that receives the second pulse and applies a welding voltage between the stud S and the base material M.

The pulse generating circuit 21 basically includes, for example, a monostable multivibrator MM1 that generates the first pulse described above, and a monostable multivibrator that acts so as to rise at the trailing edge of the first pulse.
It is set as MM2. However, as shown by the broken line, an intermediate pulse generator 24 may also be provided between the multivibrators MM1 and MM2. This intermediate pulse generator 24 is a monostable multivibrator MM1
An intermediate pulse is generated that rises after a predetermined period of time has elapsed after the rise of the first pulse and before the trailing edge of the first pulse appears (Fig. 3), and the rise of this intermediate pulse causes a monostable state. multi vibrator
A second pulse is generated from MM2 (broken line in Figure 3). As will be described later, this intermediate pulse is generated when the stud rapidly comes into contact with the base metal due to demagnetization of the lift coil, and a predetermined gap cannot be obtained between the stud and the base metal when the welding voltage is applied. is required. In other words, the intermediate pulse accelerates the rise time of the second pulse and is effective in demagnetizing the lift coil when the compressive force of the spring 11 is strong and the time required for the stud to contact the base material after demagnetizing the lift coil is extremely short. A welding voltage is applied in advance to ensure a predetermined gap between the stud and the base metal. Therefore, it goes without saying that if a predetermined gap can be ensured, the intermediate pulse will be unnecessary.

The outputs of multivibrators MM1 and MM2 are sent to circuits 22 and 22 via shaping and amplification circuits 25 and 26, respectively.
23 respectively. For example, a delay circuit can be used instead of the multivibrator.
Moreover, the intermediate pulse generator 24 can be realized by a delay circuit or a monostable multivibrator. In any case, the pulse generation circuit 21 generates a first pulse having a width to excite the lift coil for a predetermined time after the trigger 4 is operated, and a second pulse that rises after the elapse of a predetermined time of the first pulse. It is fine if it is done.

The lift coil power supply circuit 22 converts the alternating current voltage appearing in one secondary winding of the transformer _T1 into a direct current voltage using a rectifying and smoothing circuit consisting of a rectifier _D1 , a resistor _R1, and a capacitor _C1 . One of the voltages is connected to one end of the lift coil 12. The other end of the lift coil 12 is connected to the other polarity of the DC voltage via a transistor T _r , and the base of the transistor T _r has a
A first pulse is input from the circuit 24 of the pulse generating circuit 21. Therefore, when the first pulse occurs, the transistor T _r becomes conductive, and the lift coil 12
A current is supplied to the magnet. Note that the diode
D ₂ serves to prevent overvoltage due to the reaction of the current flowing through the coil 12.

The welding power supply circuit 23 is well known and includes a triax D ₃ , a rectifier D ₄ , a resistor R ₂ , a capacitor C ₂ ,
and thyristor _D5 , one output end is connected to stud S via spindle 7 and collector 5.
The other output terminal is connected to the base material M, and the charge charged in the capacitor _C2 is supplied to the stud S by the conduction of the thyristor _D5 . thyristor
Circuit 2 of the pulse generation circuit 21 is connected to the gate of _D5 .
A second pulse is supplied from D5, which causes thyristor _D5 to conduct.

The operation of the stud welding equipment described above is shown in Figure 2a.
This will be explained with reference to FIG.

First, the stud S is held in the collet 5 with the tip T of the head facing down (FIG. 2a), and the tip of the stud projects beyond the nose 6. While holding the stud S, the tip T is applied to a predetermined position on the base material M and the entire tool is pressed (FIG. 2b).
At this time, since the tip T is in a protruding state, it can be accurately positioned on the base material. Next, when the trigger 4 of the grip 2 is pulled, a trigger signal (FIG. 3) is generated, and the pulse generating circuit 21 generates a first pulse of a predetermined width. As a result, the lift coil 12 is energized, and the spindle 7, collet 5, and stud S are pulled up (FIG. 2c), and a predetermined gap G is created between the stud S and the base material M.

After the lift coil 12 is excited by the first pulse and a gap G is formed between the stud S and the base material M, the first pulse disappears (solid line in Figure 3) or (an intermediate pulse occurs). vessel 24
(if the third
(dashed line in the figure), a second pulse is generated, thyristor _D5 becomes conductive, and a capacitor is connected between stud S and base material M.
Welding voltage is applied from _C2 . An arc discharge occurs just before the stud S contacts the base metal M, and when they subsequently come into contact (Fig. 2 d), welding current (Fig. 3) flows instantaneously, and the tip T of the stud S and its head The end surface of the part is welded to the base material M.

In this way, since the stud pulling operation is performed automatically, the effort and time required for the lifting operation is eliminated, welding defects due to forgetting to pull the stud can be avoided, and the positioning of the stud to the base metal is also accurate. Become.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a control circuit and tool of a gap type stud welding apparatus according to the present invention, and FIG.
Figures a to e are explanatory diagrams of the operation of the stud welding apparatus according to the present invention, and Figure 3 is a time chart of the control circuit. 1... Stud welding tool, 2... Body, 3... Grip,
4...Trigger, 5...Collection, 6...Nose, 7...Spindle (rod-shaped member), 11...Spring, 12...Lift coil, 14...Stop pin, 15...Armature, 20...Control circuit, 21...Pulse generation circuit, 2
2... Lift coil power supply circuit, 23... Welding power supply circuit, M... Base metal, S... Stud, T... Chip.

Claims (1)

[Scope of Claims] 1. A collet capable of holding a stud at its tip, and a nose extending toward the tip so as to surround this collet, and during welding, the collet is provided with a tip of the stud held at a predetermined distance from the tip of the nose. In a stud welding device that is raised in height to create a gap between the stud and the base metal, there is a spring that pushes the collet toward the tip and urges the tip of the stud to protrude from the tip of the nose; A rod-shaped member provided at the rear end, at least the rear end of which is made of a magnetic material, and a stud that is placed adjacent to the rear end of this rod-shaped member and is held in the collet together with the rod-shaped member when excited, to the predetermined height. A lift coil that acts to lift the stud and a trigger on the main body of the device are operated to excite the lift coil and lift the stud to the predetermined height from the base material to form a predetermined gap between the stud and the base material. After that, apply welding voltage between the stud and base metal,
A gap type stud welding device comprising a control circuit that then demagnetizes the lift coil and brings the stud into contact with the base material. 2. The device according to item 1, wherein the spring is provided between the rod-shaped member and the device main body. 3. The control circuit applies a welding voltage between the stud and the base material after a first pulse of a predetermined width for excitation of the lift coil and a predetermined period of time after the rise of this first pulse, in response to a trigger signal from the trigger. a pulse generating circuit that generates a second pulse of 2. The apparatus according to item 1, further comprising a welding power source for applying an applied welding power source. 4. The device according to item 3, wherein the second pulse is formed to rise at the trailing edge of the first pulse. 5. The device according to item 3, wherein the second pulse is formed to rise before the trailing edge of the first pulse.