JPS58181481A - Stud welding method - Google Patents

Abstract

PURPOSE:To perform optimum welding without the influence of the margin for projection of a stud and the force at which the stud is pressed to a base material, by detecting the position of the stud with a solenoid, changing the delay time for electric discharge in accordance with the detected position and enabling. optimum discharge when the stud arrives at the base material. CONSTITUTION:The position of a stud 4 set in a stud gun 1 is detected by the change in the reactance of a solenoid when the stud 4 is pressed to a base material 5. The stud 4 is pulled from the material 5, and the timing for electric discharge in the stage of returning the stud 4 from said state to the material 5 is set with a delay circuit for discharge so that an optimum discharge state is obtained. The above-mentioned delay circuit changes the delay time in accordance with the change in the reactance. The optimum welding is accomplished by the above-mentioned method without the influence of the margin for projection of the stud 4 and the force at which the stud is pressed to the base material.

Description

[Detailed description of the invention] The present invention relates to a stud welding method.

Conventionally, the welding length of a stud for sheet metal parts, etc. has been determined by using a stud gun 1 that grips the stud. I! Welded product (hereinafter referred to as 4)
This is done by manually or mechanically stirring and evaporating the surface of the Ik base material. The welding conditions of the rounded stud gun 1 for this welding (protrusion allowance, retraction allowance, 416 hours of discharge,
Settings (voltage, etc.) are made using a test panel, etc.

However, even when optimum conditions are set using test panels, the flatness of the surface of the base material varies depending on the location, so it is difficult to maintain constant quality at all times, and sometimes welding defects occur.

That is, the stud gun 1 (hereinafter referred to as the gun) has the configuration shown in the first picture, and the welding method is to first set the stud 4 in the chuck 5 of the gun 1, and then (@
At threshold 11, the tip of the ρ spark shield 2, which is not set with a stud, is pressed against the base material 5. Then, the nine studs 4 set in the chuck 5 are pressed against the base material 5 as shown in FIG. 2A. (However, in Figure 2, stud 4
The other chuck 5, spark shield 2, etc. are omitted to simplify the explanation. Then, when the start switch 6 is pulled, a pilot current flows between the base material 5 and the stud 4, and at the same time The solenoid 7 installed in the gun 1 is energized, and the stud 4 is gently pulled away from the base material 5 together with the chuck 3 by the V-rinder 8 and piston rod 9 as shown in FIG. 2B. A pilot arc PA is generated between the base metal 5 and the tip of the stud 4 at and and 4. After this state continues for a certain period of time, the excitation of the solenoid 7 is cut off, and the stud 4 is pushed back toward the base material 5 by the repulsive force of the spring 100 of the gun 1, as shown in 2'6C. After a slight delay, the discharge of the capacitor starts (this delay is conventionally set to a constant value as a discharge delay time). When the stud 4 reaches the base metal 5, welding is completed.

(#!2 Figure D) However, if there are uneven parts in the base material 5 as shown in Figures 5 and 5, the lifting allowances 11 and 12 of the stud 4 will be different, and as shown in Figures 4 and 5. Since the release delay time t from the start of descent S to the start of discharge of the capacitor shown in Fig. 6 is constant, and the backward movement of the cylinder 8 is set to a predetermined value by the adjustable core screw 15, the lifting allowance 11 is In the case shown in Figure 3, Figure 41, where l1>l for the set pulling distance l, the stud 4 is attached to the base material 5.
After the base metal 5 cools until the capacitor discharge ends and the arc reaches the end, the stud 4 vaporizes, resulting in a welding failure. (Ll is the movement of the stud 4 when the base material is normal, and Ll is the movement of the stud when the base material is normal.
In the case shown in FIGS. 5 and 6, when the stud 4 reaches the base material 5, the discharge tD of the capacitor starts at 1f111N, and most of the main arc is short #! This leads to a large number of drawbacks, such as a welding failure due to a decrease in the arc that melts the stud 4 and the base metal 5.

The present invention was made in view of the above circumstances, and is a stud welding method that allows stable and best welding to be performed at all times without being affected by the protrusion of the stud, the pressing force against the base material, the irregularities of the base material, etc. The purpose of this service is to provide the following information:

In order to achieve the above object, in the present invention, the stud WI connection method uses a solenoid to detect the position of the stud when the stud is pressed against the base material, and then the stud is pulled up from the base material, and this pulling up is performed depending on the condition. Push back the base material hestad I
The special feature is that the discharge timing for the festival is performed by a discharge delay circuit whose delay time is varied by the reactance change.

The following is a simplified version of the present invention! Examples will be described in detail with reference to the drawings.

In Figure @1, a gun 1 for stud welding has a gun head 11. This gun head 11 is provided with a cylindrical spark shield 2 on one left side thereof to prevent welding sparks from scattering.

This spark shield 2 has a chuck 5 at the center of its inner mouth for setting the T stud 4, and a piston rod 9 is further provided at the axial center of the chuck 5.

A piston j2i1m is bored at the right end of the piston rod 9), and this piston 12 is slidably inserted into the cylinder 8. The cylinder 8 is biased to the left in the figure by a spring 10, and
A solenoid 7 is provided at the outer periphery of the right end of the cylinder 8.
Furthermore, on the right side of this, there is provided a staple core screw 1-15 which is screwed onto the parallel plate 14. In addition, when the piston 12 and the cylinder 8 pieces are welded, By injecting high pressure air into the cylinder 8 from a compressor (not shown), the piston 12 is fixed to the cylinder 8 and the pressure is maintained as shown in FIG.

When the gun 1 for rounding and stud welding is turned on by pulling the switch 6, the cylinder 8 is attracted against the biasing force of the spring 10, and the piston rod 9 and chuck 5 are simultaneously moved to the right. The solenoid 7 is used not only for suctioning the cylinder 8 but also as a sensor for detecting the position of the cylinder 8. However, they can also be installed separately without being used together.

Next, this example control 4I! l! Explaining the J path 16 based on FIG. 9, this 1vll# circuit 16 includes a delay circuit 17, a discharge MIIIl circuit, a circuit 18, and a chuck release 11! It is mainly composed of a delay circuit 19, a re-excitation delay circuit 20, a boost circuit 21, an interlock circuit 22, a reactance voltage conversion circuit 25, a solenoid driver 24, a power indicator 27, an MR indicator 26, and transformers TRI and TR2. ing.

In such a configuration, the operator first sets the chuck 3KT stud 4 of the gun 1 and then brings it into contact with the base material 5 at a predetermined position. Thereafter, the tip of the spark shield 2 is brought into contact with the base material 5 as shown in FIG. 8 against the force of the spring 10.

In this state, the y9 cylinder 8 has moved backward by 41 (I!l is normally 1.6 ff) as shown in Fig. 7, and when the start switch 6 is pressed, the solenoid 7 is energized and the cylinder 8 is activated by the assy tag. lv: f askri.

-15, further retreat by Kl (1,6M).

In other words, this letter is in a regular state,
If the base metal 5 has four parts as shown in Figures 3 and 4, push the spark and shield 2 back into the base metal, and the retracted position of the cylinder 8 with a nine-shaped face is the normal position shown in Figure 7. 111PR, and for example, only 1['WR, which is 4 points ahead of this, will be retreated, so the lifting amount will be 11, which is longer than l. Therefore, in this example, the solenoid 7 which changes depending on the retreating position of the cylinder 8. Detect the glue actance, change the time t111I according to this, and set the stud 4.
When inserted into the base material 5, it is spuntrol so that it becomes a regular discharge-like ball.

In other words, in FIG. 9, the contact between the stud 4 and the base metal 5 when the spark shield 2 is pressed against the base metal is detected by the change in current value caused by this contact (K (10th
1 threshold A), which is input to the determination circuit 25 for determining the allowable angle g as the contact detection signal DE. Then, the determination circuit 25 determines whether the attachment of the stud 40 to the layer material 5 is within the permissible range based on the pressure from the reactance voltage conversion circuit 25. Turning off the delivery Y indicator light 26 (Fig. 10C), interlock [i! I
Release of the bribe 22 (this releases the lock of the starting switch 6) and a!, which will be described later, from the reactance voltage conversion circuit 25 to the discharge delay circuit 18 ! An extended opening time setting signal is issued.

Next, when the start switch 6 is pressed when the READY indicator light 26 lights up (FIG. 10D), the start signal is delayed [circuit 17].
, the pilot arc signal circuit 28, and the solenoid driver 24, respectively.

Therefore, a pilot current flows from the stud 4 (10th factor B), and the delay circuit 17 does not start the timed operation.
1'llG''), the solenoid 7 is energized by the solenoid driver 24 (Fig. 110E) and the stud 4 is pulled up. Then, when the delay circuit 17 times up (lI/I, time t1 in Fig. 10G), a signal due to this time-up is generated. is sent to the discharge delay i!!, circuit 18, chuck separation delay circuit 1h, and solenoid driver 24, so that the discharge delay circuit 18 and the chuck separation delay circuit 19
starts the time period (time period t1 in FIG. 10 H,

(This is the time S of the 21st station, Figure 4, and the 6th river.) Therefore, the stud 4 is pushed back to the base metal 5 by the repulsive force of the spring 10, but (at this time, the base metal contact detection signal DW
occurs. @Figure 10 A time t3) In the middle of this push-back operation, the release t4 extension 1 circuit 18 times up (time t3).
MH time 115t 2) To Bastfuns 21! A time-up signal is sent.

To explain this in more detail, if the surface of the base material 5 is uneven as described above, the discharge delay circuit 18 ii! !
The unpleasant time is set according to the unevenness.

That is, as shown in the 51st Shu or the 5th Ku, the base material 5
If there are irregularities on the surface of the cylinder 8, when the stud 4 is pressed against the base metal 5, the cap of the cylinder 8 shown in the 7th line will not be in the normal state PR, for example, as shown in the WR shown by the line 11. position. Therefore, how much the backward position has deviated from this normal position is emitted by the change in the inductance of the solenoid 7, and this is converted to a positive value by the reactance (positive conversion circuit 23), which is used to set the delay time. Depending on the height of this positive value (which becomes a signal), a delay (8
) The delay time of path 17 is set (the setting of 44 hours is performed, for example, by a circuit consisting of an integrating circuit and a comparator), and tb, for example, when there is a recess in the base material 5 as shown in FIG. The KN elongation time is set to tIK as shown in FIG. 4, and if the base material 5 has a convex portion as shown in FIG. ! This is why the delay time is set to t2.

When the delay time of the discharge delay circuit 18 set in this manner has elapsed and a time-up signal is sent to the bus stop function 21 and the thyristor 5CRI is triggered, the electric charge of the main sensor t01 is discharged (see Fig. 10). J time 1
2) A main arc is generated between the stud 4 and the base metal 5, and the stud 4 is connected to the base metal 5 immediately after the main arc ends (time E shown in Figures 2 (B), 4, and 6N). When the welding process reaches (101st time A time t3), the welding ends.

Furthermore, the chuck release delay circuit 19 times up (time t4 in Fig. 10) and the solenoid driver 2
4, the solenoid 7 is re-energized (101st time t4), and the chuck 5 is moved to the base material 5.
I'm drawn back more. At this time, the stud 4 welded to the base material 5 is automatically pulled away from the chuck 3 by this pulling back action. t, said chuck pull ls'# extension circuit 19
Re-Ui that starts timed operation due to the time-up of
j) When the magnetic timer 20 times up (time t5' in FIG. 10), a time-up signal is sent to the solenoid driver 24, and the re-excitation of the solenoid 7 is canceled. (Time t5 in FIG. 10) Then, when the gun 1 is pulled away from the base material 5, all welding operations are completed.

As explained above, in the present invention, when the stud is pressed against the base material, the position of the stud is detected by a solenoid,
Next, the stud is pulled up from the base metal, and the discharge timing when pushing the stud back to the base metal from this lifted state is determined by the reactance change I! J! The extension time is variable (3I!!II1. The stud m-connection method set by the circuit provides a stable and optimum performance regardless of the protrusion of the stud, the pressing force against the base material, the unevenness of the base material, etc.) S of
It has the characteristic of being able to communicate with others.

[Brief explanation of the drawing]

The drawing embodies the invention - v7! This is an example.
Figure 1 is a cross-sectional view of the gun, Figure 2 (a) is an explanatory diagram showing the movement of the stud in a normal base metal, and Figure 2 (b) is an explanatory diagram showing the movement of the stud and changes in current. , Figure 3 is an explanatory diagram showing the movement of the stud in a base material having four parts, @ Figure 4 is an explanatory diagram showing the change of the stud and current in a base metal having four parts, and Figure 5 is an explanatory diagram showing the change in the current in a base material having four parts. Figure 6 is an explanatory diagram showing the movement of the stud in a base metal with a convex part and changes in current. Fig. 8 is an explanatory drawing showing the state in which the tip of the gun is pressed against a normal base material, Fig. 9 is a block diagram of the control circuit, and the 101st threshold is the timing of the control circuit. It is a chart. 1...Gun 2...
Sparkshi 1v Dro... Chat Ri
4...Stat
5...Base material 7...C
Linda 16...control@circuit 18...4 discharges 1 river 23...reactance voltage f conversion circuit

Claims (1)

[Claims] A solenoid detects the position of the stud when it is pressed against the base material, and a discharge ill! ! ! A welding method using a stud welding machine having a spreading circuit, in which when the stud is pressed against the base metal, the position of the stud is first detected by the change in actance of the total solenoid, and then the stud is pulled up from the base metal, The discharge timing when pushing back to the base metal hestad from this raised chestnut is determined by the reactance change.The discharge delay 14 allows the delay time to be used.
A stud welding method characterized by setting the stud according to the circuit.