JP2000126869A - Resistance welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide resistance welding equipment capable of dispensing with management, etc., of a welding electrode length, welding with imparting desired welding force to an object to be welded, obtaining fixed welding quality thereby and reducing its cost. SOLUTION: When a motor 30 arranged to a support column 28 of resistance welding equipment is rotated and a clutch part 35 of a clutch brake mechanism 32 is connected, a cylindrical groove cam is rotated, the rotating motion is converted to a linear motion with a follower 60. As a result, the pressurizing mechanism 13 is descended together with an upper welding electrode 12, objects 146, 148 to be welded are held between a lower welding electrode 14 and the upper welding electrode 12. When the pressurizing mechanism 13 is further displaced, the upper welding electrode 12 is displaced for a body 76 of the pressurizing mechanism 13. The welding force P is detected by a strain gage, when the welding force P coincides with a welding force set value P1, a welding current is caused to flow from a welding power source 20, the objects 146, 148 are welded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance welding apparatus for performing welding by bringing two types of workpieces into contact with each other and supplying current thereto.

[0002]

2. Description of the Related Art In resistance welding, two types of workpieces are brought into contact with each other and a current is applied while mechanically pressing the workpieces. The basic principle is that the contact resistance is lower than that of the parts, the welding current is concentrated and Joule heat is generated, and as a result, the molten state of the metal parts is obtained, and the metal parts are welded together with the pressing force. In this case, the welding quality largely depends on three factors: welding current, welding time, and pressing force.

[0003] As an apparatus for performing such resistance welding, for example, a movable electrode is brought close to a fixed electrode by a displacement mechanism such as an air cylinder or the like, and an object to be welded is clamped and pressed by the movable electrode and the fixed electrode to perform welding. Things are known.

[0004]

However, in the above-described resistance welding apparatus according to the prior art, for example, when an air cylinder is used as a displacement mechanism, a movable electrode is formed so that welding can be performed with a predetermined pressing force. It is necessary to adjust the position of the stopper that determines the stop position of the first position with high accuracy, and the operation becomes complicated.

On the other hand, using a pulse motor for the displacement mechanism,
If the rotary motion of the pulse motor is converted to linear motion by a ball screw, the stop position accuracy of the movable electrode can be improved, but the cost of the resistance welding device is increased because the pulse motor and the ball screw are expensive. There is a problem of soaring.

Moreover, in any of these methods, the amount of displacement of the movable electrode is converted into a pressing force.
For example, if there is a temporal change in the elastic coefficient of a spring or the like that presses the movable electrode against the work to be welded, or if the welding electrode is worn, an accurate pressing force cannot be obtained.
Therefore, it is necessary to always manage these elements.

However, under the present circumstances, for example, a constant pressure is obtained after measuring the pressure at the start of work or the like, and adjusting the displacement amount so that the pressure becomes a predetermined value. Since the operation is performed on the premise, it is not guaranteed that all the workpieces are necessarily welded with a desired welding quality, assuming that the pressure force fluctuates during the operation.

In view of the above, a pressing force detecting means for detecting a pressing force applied to the workpiece by the movable electrode and the fixed electrode is connected to a displacement mechanism, and when the pressing force reaches a predetermined value, an air cylinder or a pulse motor is used. There is a method in which the welding is stopped and the welding electrode length is not required.

However, when an air cylinder is used, the accuracy of the stop position of the movable electrode is low, and it is difficult to obtain a desired pressing force on the workpiece by the movable electrode and the fixed electrode. On the other hand, when a pulse motor is used, the pulse motor and the ball screw are expensive, as described above, and the cost of the resistance welding apparatus rises.

[0010] Further, by using a torque motor to convert the rotary motion into a linear motion to displace the movable electrode and press the movable electrode against the workpiece with a constant torque, the length of the welding electrode can be reduced. However, it is difficult to generate accurate torque, and the applied force of the movable electrode and the fixed electrode to the work to be welded varies. There is a problem that it cannot be kept constant.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is not necessary to control the length of a welding electrode and the like, and it is possible to perform welding by applying a desired pressing force to an object to be welded. Accordingly, it is an object of the present invention to provide a resistance welding apparatus which can obtain a constant welding quality and can reduce the price.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a resistance welding apparatus for performing resistance welding by sandwiching an object to be welded between the welding electrodes and conducting an electric current. A displacement mechanism for displacing the welding electrode with respect to the other welding electrode, a pressing force detecting means for detecting a pressing force of the welding electrode on the workpiece, and a stop mechanism for stopping the displacement of the one welding electrode. The displacement mechanism is provided on the welding electrode side, a motor controlled according to the pressing force detected by the pressing force detecting means, a cam member driven by the motor, and engaged with the cam member; And a follower for displacing the welding electrode in accordance with the driving of the cam member.

According to the present invention, when the motor rotates, the cam member rotates, and the follower converts this rotational movement into linear movement, and one of the welding electrodes is displaced toward the workpiece. The welding electrode presses the workpiece, the pressing force at this time is detected by the pressing force detecting means, and when the pressing force reaches a predetermined value, the displacement of the welding electrode is stopped by the stop mechanism, and the welding current is reduced. Weld by conducting electricity.

In this case, if the stopping mechanism comprises a brake for stopping the driving of the cam member and a clutch for intermittently connecting the cam member and the motor, the cam member can be stopped instantaneously and the welding electrode can be stopped. Is instantaneously stopped, which is preferable.

Further, the cam member has a cylindrical grooved cam formed by forming a groove inclining with respect to the axial direction on the outer periphery of the cylindrical member. The distance between the disk member and the center of rotation of the disk member changes. Either a grooved cam formed by a groove orbiting, a plate cam having an outer peripheral surface that changes as the distance from the center of rotation changes, or an end surface cam whose one end surface of a cylindrical member is inclined with respect to its axial direction. Can also be used.

Further, according to the present invention, in a resistance welding apparatus for performing resistance welding by sandwiching a workpiece between welding electrodes and energizing the same, setting means for setting a pressing force of the welding electrode on the workpiece. Display means for displaying the set pressing force; a displacement mechanism for displacing one welding electrode with respect to the other welding electrode; and a pressing force detecting means for detecting a pressing force of the welding electrode on the workpiece. And the following.

In this case, the operator can set a desired pressure on the basis of the display on the display means, and the displacement mechanism displaces the welding electrode so as to obtain the set pressure. be able to.

In addition, by displaying the set pressing force and the detected pressing force on the display means, the operator can perform the work while checking the actual pressing force.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a resistance welding apparatus according to the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 denotes a resistance welding apparatus according to an embodiment of the present invention. The resistance welding apparatus 10 includes a pressing mechanism 13 provided with an upper welding electrode 12.
A displacement mechanism 16 for displacing the welding mechanism in a direction to approach or separate from the lower welding electrode 14, a controller 18 for controlling the displacement mechanism 16, and a welding current to the upper welding electrode 12 and the lower welding electrode 14 under the control of the controller 18. And a welding power supply 20 for energizing. Note that a foot switch 19 for starting the resistance welding apparatus 10 is connected to the controller 18.

The controller 18 is provided with an LCD display 18a for displaying the operation status and the like of the resistance welding apparatus 10, and a plurality of setting switches 18b for setting and operating the resistance welding apparatus 10. The setting switch 18b
Functions as setting means for setting the pressing force of the pressing mechanism 13 on the workpiece. The LCD display 18a functions as a display unit that displays the set pressing force and displays the pressing force detected during the operation of the resistance welding apparatus 10.

The displacement mechanism 16 has a base 22, as shown in FIG. The lower electrode holder 24 is fixed to the base 22, and the lower welding electrode 14 is fixed to the lower electrode holder 24. An electric wire 26 for supplying a welding current from the welding power source 20 to the lower welding electrode 14 is connected to the lower electrode holder 24.

A support 28 is erected on the base 22, and the support 2 is
A motor 30 is provided on an upper part of the motor 8. A clutch brake mechanism 32 is connected to the motor 30. As shown in FIGS. 3A and 3B, the clutch brake mechanism 32
4, a clutch unit 35 and a brake unit 37 are disposed inside the housing 34. The clutch unit 35 is a motor 3
The clutch plate 36 is fixed to the rotation shaft 0, and a disk member 40 connected to the output shaft 38 faces the clutch plate 36. The disk member 40 is provided with spring members 42a and 42b, and the spring members 42a and 42b are provided with ring-shaped contacts 44a and 44b made of a magnetic material. Inside the housing 34, there are disposed a clutch excitation coil 46 to which the contacts 44a and 44b can approach and separate, and a brake excitation coil 48 constituting the brake unit 37. Brake plate 50
Is fixed.

A cylindrical member 56 constituting a cylindrical groove cam 54 is fixed to the output shaft 38, and a groove 58 inclined around the axis of the cylindrical member 56 is formed around the outer periphery of the cylindrical member 56 as shown in FIG. Formed. A roller 62 constituting a follower 60 is rotatably inserted into the groove 58, and the roller 62 is rotatably provided on a displacement plate 64 via a support member 63 (see FIG. 2). A guide block 66 is fixed to the displacement plate 64, and a hole 68 extending in the vertical direction is formed in the guide block 66. Bushings 70a and 70b are provided on the wall forming the hole 68. Bush 70a, 70b
The guide rod 72 provided in the column 28 extends vertically through the supporting members 71a and 71b through the support members 71a and 71b. Therefore, the displacement plate 64 can be displaced in the vertical direction along the guide rod 72. Be composed.

The pressing mechanism 13 is fixed to the displacement plate 64. The pressing mechanism 13 includes a body 76 as shown in FIG. The body 76 has a lower body 78 and an upper body 80, and through holes 82 and 84 are formed from the lower body 78 to the upper body 80. Linear ball bearings 86, 88 are provided in the through holes 82, 84, and a pressure transmitting shaft 90 is provided in the linear ball bearings 86, 88.
Are slidably inserted. The upper welding electrode 12 is connected to the lower portion of the pressure transmission shaft 90 via an upper electrode holder 92.
Is attached. An electric wire 94 for supplying a welding current from the welding power source 20 to the upper welding electrode 12 is connected to the upper electrode holder 92 (see FIG. 2).

A first spring receiver 96 is fixed to the upper portion of the pressure transmission shaft 90 via bolts, and one end of a coil spring 100 is seated on the first spring receiver 96. Coil spring 100 has upper body 8
The cylindrical member 104 is fitted in the concave portion 102 formed in the recess 102, and the distal end portion of the cylindrical member 104 is fitted in the concave portion 102. The cylindrical member 104 is fixed to the upper body 80 by screwing a nut 106 into a screw engraved on the outer periphery thereof.

A second spring receiver 108 is slidably inserted into the cylindrical member 104, and the other end of the coil spring 100 is seated in the second spring receiver 108. A recess 110 is formed in the upper center of the second spring receiver 108, and a first ball member 112 is seated in the recess 110. A spacer 114 is slidably provided inside the cylindrical member 104 at a predetermined distance from the second spring receiver 108. A recess 116 is formed in the spacer 114 so as to face the recess 110, and the upper portion of the first ball member 112 is seated in the recess 116. A recess 118 is formed in the upper center of the spacer 114, and a detector 122 of a strain gauge (load cell) 120, which is a pressing force detecting means, sits in the recess 118. A lead 124 connected to the controller 18 is led out from the strain gauge 120 (see FIG. 1), and the pressure applied to the upper welding electrode 12 via the lead 124 is extracted as an electric signal. As the strain gauge 120, a gauge utilizing a change in resistance of a metal or a semiconductor can be used.

Above the strain gauge 120, the contact plate 12
8 are provided. A curved concave portion 1 is provided at the upper part of the plate 128.
The second ball member 136 is sandwiched between a curved recess 134 formed at the tip of the pressing force adjusting knob 132. Pressing force adjustment knob 132 is nut 1
Case 140 screwed into cylindrical member 104 by 38
Is held firmly.

The resistance welding apparatus 10 according to the present embodiment
Basically, the configuration is as described above. Next, the operation and operation and effect will be described.

First, prior to the welding operation, the controller 1
With 8 the setting switch 18b, for setting the desired pressure setpoint P ₁ and P ₂ for the reference of starting welding. In this case, the inputted pressure set value P ₁ and P ₂ by the operator, to be displayed on the LCD display 18a, it is confirmed that entered the desired set value.

Therefore, as shown in FIG. 2, the workpieces 146, 14 are placed between the lower welding electrode 14 and the upper welding electrode 12.
8 are superposed and arranged (Step S1 in FIG. 7). Also,
As shown in FIG. 3B, an electric current is applied to the brake excitation coil 48 to draw the contact 44 b, thereby bringing the contact 44 b into contact with the brake plate 50 and separating the contact 44 a from the clutch plate 36. Therefore, the brake is applied to the output shaft 38 and the cylindrical groove cam 54 does not rotate.

After the above-described preparatory steps, when the operator operates the foot switch 19 and drives the motor 30 under the control of the controller 18, the clutch plate 36 rotates. 44a is the clutch plate 36
Since the contact 44b is in contact with the brake plate 50, the cylindrical groove cam 54 is stopped. When the current supplied to the brake excitation coil 48 is stopped and the current is supplied to the clutch excitation coil 46,
As shown in FIG. 3A, the contact 44 b separates from the brake plate 50, and the contact 44 a contacts the clutch plate 36, and the rotational force of the motor 30 is transmitted to the cylindrical groove cam 54. Then, the rotary motion is converted into a linear motion by the rollers 62 engaged with the groove 58 of the cylindrical groove cam 54, and the pressurizing mechanism 13 is lowered (step S2). Therefore, the upper welding electrode 12 abuts on the upper surface of the workpiece 148, and the workpieces 146 and 148 are the upper welding electrode 12 and the lower welding electrode 14.
(See FIG. 6A).

The upper welding electrode 12 presses the workpiece 148 under the further lowering action of the pressing mechanism 13, and the pressing force transmission shaft 90 relatively rises against the elastic force of the coil spring 100 (FIG. 5). Therefore, the coil spring 100 contracts, and the pressing force P of the upper welding electrode 12 on the workpiece 148 gradually increases. The magnitude of the pressure P is measured by the strain gauge 120.

At this time, the first ball member 112 and the second
Of the ball member 136, the pressing mechanism 13
6 and 148, even if the angle is changed, plays the role of faithfully transmitting the fluctuation of the pressing force P to the strain gauge 120. Therefore, the objects to be welded 146, 1
The pressing force P is reliably transmitted to the strain gauge 120 even when 48 is inclined.

The controller 18 compares the pressure P with a predetermined pressure set value P ₁ (step S 3). If the pressure P is smaller than the pressure set value P ₁ , the process returns to step S 2, and the pressurizing mechanism 13 is further lowered. The pressure P is current energizing the brake excitation coil 48 with a current that is energized to the clutch exciting coil 46 at the time that matches the pressure setpoint P ₁ is stopped, the contact 44a is a clutch plate 36 and the contact 4
4b comes into contact with the brake plate 50 to apply the brake, and the rotation of the cylindrical groove cam 54 stops. For this reason, the pressing mechanism 1
3 of descent is stopped (step S4), and is maintained in a state weld object 148 being pressed by the pressure setpoint P ₁ to the upper welding electrode 12. As described above, since the workpieces 146 and 148 are sandwiched between the upper welding electrode 12 and the lower welding electrode 14 at the pressing force set value P ₁ , the workpieces 146 and 148 are located between the upper welding electrode 12 and the workpiece 148. Contact resistance between 146 and workpiece 148 and between workpiece 146 and lower welding electrode 14 are maintained at predetermined values. Further, since the rotation of the cylindrical groove cam 54 is stopped by disengaging the clutch portion 35 of the clutch brake mechanism 32 and operating the brake portion 37, the inertia of the motor 30 is not transmitted to the pressurizing mechanism 13, The pressurizing mechanism 13 can be stopped instantaneously, and the error of the pressing force P can be reduced.

It is to be noted that there is a concern that the workpieces 146 and 148 may generate vibration or the like due to an impact when sandwiched between the upper welding electrode 12 and the lower welding electrode 14. Therefore, it is preferable to maintain the state where the pressurizing mechanism 13 is stopped for a predetermined squeeze time, because vibrations and the like generated in the workpieces 146 and 148 are converged.

Next, the controller 18 controls the workpiece 14
6, 148 are welded. About this welding method, FIG.
To explain in detail based on the flowchart of FIG.
The controller 18 outputs a temporary welding command signal to the welding power source 20. Therefore, the welding power source 20 supplies a temporary welding current between the upper welding electrode 12 and the lower welding electrode 14 in accordance with the temporary welding command signal, thereby performing temporary welding on the workpieces 146 and 148 (step S10). ). In this state, the strength is insufficient because the welding is insufficient, but the contact resistance between the workpiece 146 and the workpiece 148 is sufficiently small. Further, even if the contact resistance varies when the workpieces 146 and 148 are sandwiched between the upper welding electrode 12 and the lower welding electrode 14, the contact resistance becomes substantially constant by temporary welding.

At this time, the thicknesses of the workpieces 146 and 148 are slightly reduced by the temporary welding, and the welding force P detected by the strain gauge 120 due to the displacement of the upper welding electrode 12 is smaller than the welding force set value P _1. Become. Therefore, the controller 18 controls the clutch brake mechanism 32 while measuring the pressing force P with the strain gauge 120 to connect the clutch unit 35 and release the brake unit 37, thereby transmitting the rotational force of the motor 30 to the cylindrical groove cam 54. Communicate,
The pressing mechanism 13 is lowered (Step S11). The controller 18 compares the a predetermined pressure setpoint P ₂ pressure P (step S12), the pressure P is pressure set value P ₂
At the same time, the clutch brake mechanism 32 is controlled to release the connection of the clutch unit 35 and the brake unit 3
7, the rotation of the cylindrical groove cam 54 is stopped, and the lowering of the pressing mechanism 13 is stopped (step S1).
3).

Next, the controller 18 outputs a main welding command signal to the welding power source 20, and the welding power source 20 applies a main welding current between the upper welding electrode 12 and the lower welding electrode 14,
The main welding is performed on the objects 146 and 148 (step S14). At this time, since the contact resistance between the workpiece 146 and the workpiece 148 is sufficiently small due to the temporary welding and there is no variation, the nugget 150 having a predetermined size is formed by the main welding current as shown in FIG. 6B. And good welding is performed.

At this time, the nuggets 150 formed on the workpieces 146 and 148 are in a molten state. Therefore, after a predetermined hold time has elapsed, the nugget 150 is solidified.

When the controller 18 rotates the motor 30 in the reverse direction and controls the clutch brake mechanism 32 to rotate the cylindrical groove cam 54, the pressing mechanism 13
Rise, and the objects 146 and 148 to be welded are taken out (step S15).

According to the present embodiment, the strain gauge 1
20, the welding pressure P of the upper welding electrode 12 is measured, and the welding is performed when the welding pressure P reaches the welding pressure set value P _1. Therefore, it is necessary to control the lengths of the upper welding electrode 12 and the lower welding electrode 14. , Welding work becomes easier and the number of maintenance steps is reduced.

Unlike the prior art, no ball screw or compressed air supply source is required, and the cost of the resistance welding apparatus 10 can be reduced.

Further, when the displacement of the pressurizing mechanism 13 is stopped, the transmission of the rotational force of the motor 30 is disconnected by the clutch 35 of the clutch brake mechanism 32 and the brake 37
Since the rotation of the cylindrical groove cam 54 is braked by the force, the pressurizing mechanism 13 is prevented from being unnecessarily displaced by the inertia of the motor 30, and the pressing force P of the upper welding electrode 12 against the workpiece 148 is prevented. Can be accurately controlled.

In the present embodiment, welding is performed in two steps, temporary welding and main welding, but welding may be performed only once. In this case, work time can be reduced.

Further, welding may be performed without stopping the lowering of the pressurizing mechanism 13 in step S13. This resistance welding method will be described with reference to FIGS.

First, prior to the welding operation, the controller 1
Using the setting switch 18b of _No. 8, a desired pressure setting value P1 as a reference for starting welding is set. In this case, pressure-force setting entered value P ₁ by the operator, to be displayed on the LCD display 18a, the desired it can be confirmed that entered set value (in FIG. 10, the pressure setpoint P ₁ Is exemplified as 2.00 kg / f.) Further, in this embodiment, if pressure P is in the pressure P after the predetermined time t has elapsed after reaching the pressure set value P ₁ is within a predetermined range based on pressure setpoint P ₂ to verify whether, using the LCD display 18a and the setting switch 18b, for setting the predetermined time t and pressure setpoint P _2.

Therefore, similarly to the above-described method, the work pieces 146, 1 are placed between the lower welding electrode 14 and the upper welding electrode 12.
When the foot switch 19 is operated by an operator by arranging the 48 in an overlapping manner (step S21), the START signal output from the foot switch 19 is supplied to the controller 18. The controller 18 drives the motor 30 according to the START signal. When the motor 30 is driven,
The pressurizing mechanism 13 descends, and the workpieces 146 and 148 are sandwiched between the upper welding electrode 12 and the lower welding electrode 14 (step S22, see FIG. 6A). Then, PSG signal according to the pressure P detected by the strain gauges 120 is supplied to the controller 18, the pressure P of the stored pressure setpoint P ₁ Toko are compared (step S23). When the pressing force P matches the pressing force set value P ₁ (see point α 1 in FIG. 11), the controller 18 outputs a WELD signal to the welding power source 20. Welding power source 2
0, when the welding signal is received, the welding current I is supplied between the upper welding electrode 12 and the lower welding electrode 14, and the welding is performed while the pressing mechanism 13 is lowered (step S2).
4).

Here, the WELD signal is output for a predetermined time t set by the operator. At a point in time after the lapse of the predetermined time t (see point α2 in FIG. 11), the controller 18 sets the strain gauge 120 detecting the pressure P on the basis of a PSG signal from, the pressure P is determined whether or not within the acceptable range relative to the pressure set value P ₂ set by the operator, in the range If OK
A signal is output, and if not within the range, an NG signal is output. Also, the LCD display 1 of the controller 18
8a displays the pressing force P at this time. Therefore,
Using the OK / NG signal or the displayed pressing force P, for example, a process such as a warning relating to the quality of the welding condition is performed, and it is confirmed at any time that the resistance welding apparatus 10 is operating normally. can do.

When welding is completed, the clutch brake mechanism 32 is controlled to stop the rotation of the cylindrical groove cam 54 and stop the lowering of the pressure mechanism 13 (step S25). After the predetermined hold time has elapsed and the nugget 150 has solidified, the controller 18 rotates the motor 30 in the reverse direction and controls the clutch brake mechanism 32 to rotate the cylindrical groove cam 54. Rise, and the objects 146 and 148 to be welded are taken out (step S26).

As described above, since welding is performed while applying the pressing force P, the welding force P does not become insufficient during welding, and good welding quality can be obtained.

Next, a resistance welding apparatus 20 according to another embodiment of the present invention using a groove cam instead of the above-mentioned cylindrical groove cam 54 as a cam member for displacing the pressing mechanism 13 is described.
0 will be described with reference to FIGS. Note that the same components as those of the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

A motor 202 and a clutch / brake mechanism 204 are provided above the column 28 of the resistance welding apparatus 200, and an output shaft 206 of the clutch / brake mechanism 204 is provided.
Are arranged to extend in the horizontal direction. The output shaft 206 is provided with a disk member 212 that forms the groove cam 210, and the disk member 212 is formed with a groove 214 that circulates so that the distance from the center of rotation changes. In the groove 214,
A roller 62 provided on the displacement plate 64 and constituting the driven joint 60 is engaged.

When the motor 202 rotates and the clutch brake mechanism 204 is controlled to transmit the torque of the motor 202 to the output shaft 206, the disk member 212 rotates. For this reason, this rotational motion is converted into linear motion by the rollers 62, and the displacement plate 64 is displaced in the vertical direction. Accordingly, the pressurizing mechanism 13 fixed to the displacement plate 64 is displaced and the workpiece 1
At 48, the upper welding electrode 12 is pressed.

A resistance welding apparatus 3 according to another embodiment.
In 00, a plate cam is used as a cam member. FIG.
4. As shown in FIG. 15, a motor 302 and a clutch brake mechanism 304 are provided above the support 28 of the resistance welding apparatus 300, and an output shaft 306 of the clutch brake mechanism 304 extends horizontally. Is done. The output shaft 306 is provided with a plate cam 312, and the plate cam 312 is formed so as to change as the distance from the center of rotation to the outer peripheral surface 314 goes around. On the outer peripheral surface 314,
The roller 62 provided on the displacement plate 64 and constituting the driven joint 60 abuts.

Motor 302, clutch brake mechanism 30
A support member 31 bent in a crank shape is provided on the upper portion of the support member 31.
6 is fixed. One end of a coil spring 318 is provided at an end of the support member 316, and the coil spring 3
The other end of 18 is provided on a support member 63 that connects the displacement plate 64 and 62. Therefore, the displacement plate 64 is always urged upward.

When the motor 302 rotates and the clutch / brake mechanism 304 is controlled and the torque of the motor 302 is transmitted to the output shaft 306, the plate cam 312 rotates. Roller 6
2 is urged by the coil spring 318 and the plate cam 312
And converts the rotational movement of the plate cam 312 into a linear movement. Therefore, the displacement plate 64 is displaced in the vertical direction. Therefore, the pressing mechanism 1 fixed to the displacement plate 64
3 is displaced, and the upper welding electrode 12 presses the workpiece 148.

In the resistance welding apparatus 400 according to still another embodiment, an end cam is used as a cam member.
As shown in FIG. 16 and FIG.
A plate-like member 402 is provided upright on the column 28, and a motor 404 and a clutch brake mechanism 406 are provided on the plate-like member 402. The output shaft 408 of the clutch brake mechanism 406 projects downward. Will be arranged. The output shaft 408 has an end cam 4 formed in a substantially cylindrical shape.
The lower end surface 414 of the end cam 412 is inclined with respect to the axis of the end cam 412. Lower end surface 414
The roller 62 provided on the displacement plate 64 and constituting the follower 60 comes into contact with.

A support member 416 which is bent in a crank shape is fixed to an upper portion of the plate member 402. Support member 4
One end of a coil spring 418 is provided at one end of the coil spring 418, and the other end of the coil spring 418 is provided on a support member 63 that connects the displacement plate 64 and the position 62. Therefore, the displacement plate 64 is constantly urged upward.

When the motor 404 rotates and the clutch brake mechanism 406 is controlled to transmit the torque of the motor 404 to the output shaft 408, the end cam 412 rotates. The roller 62 is urged by the coil spring 418 so that the end face cam 4
12, which abuts on the lower end surface 414 and converts the rotational movement of the end cam 412 into a linear movement. Therefore, the displacement plate 64 is displaced in the vertical direction. Therefore, the pressurizing mechanism 13 fixed to the displacement plate 64 is displaced, and the upper welding electrode 12
Is pressed.

In the above-described embodiment, one upper welding electrode 12 is provided for the pressurizing mechanism 13, but FIGS.
A plurality of electrodes may be provided as described below with reference to FIG.

The pressing mechanism 500 includes two upper welding electrodes 50.
4a and 504b. Housing 506 of pressure mechanism 500
Is covered by a shield 508. Holes 510a and 510b are defined in the lower part of the housing 506, and the holes 51
Bushings 512a to 512d are provided at 0a and 510b. The pressure transmitting shafts 514a and 514b are inserted through the bushes 512a to 512d,
Plate-like upper electrode holders 5 are provided at lower ends of 14a and 514b.
16a and 516b are fixed. Upper electrode holder 516
As shown in FIG. 19, bar-shaped upper welding electrodes 504a and 504b are vertically provided in the vicinity of one corner of each of the upper welding electrodes 504a and 516b. It is arranged smaller than the interval between 514a and 514b.

A plate-like member 518 is bridged above the pressing force transmission shafts 514a, 514b, and rollers 526a, 526b are rotatably supported above the plate-like member 518.

A hole 528 is defined in the housing 506, and bushings 530a and 530b are provided in the hole 528.
A shaft 532 is slidably inserted through the bushings 530a and 530b.
4 is provided swingably. Rollers 526a and 526b can freely contact the swinging member 534. Therefore, the upper welding electrodes 504a and 504b are inclined so that the workpiece 14
6 and 148, the pressing force of the coil spring 100 provided on the upper portion of the shaft 532 is divided by the swinging member 534 and the rollers 526a and 526b into substantially the same force, and is applied to the upper welding electrodes 504a and 504b. Is transmitted. Therefore, the upper welding electrode 504a and the upper welding electrode 504b are applied with substantially the same force to the workpieces 146, 148.
And the welding conditions are substantially the same (see FIG. 20).

As shown in FIG. 20, in the pressurizing mechanism 500, one upper welding electrode 504a is connected to one welding current terminal 20a of the welding power source 20, and the other upper welding electrode 504b is connected to the other welding electrode. The current terminal 20b is connected. Lower welding electrode 5 formed in a plate shape of displacement mechanism 16
36 are formed with protrusions 538a, 538b corresponding to the upper welding electrodes 504a, 504b.

One welding current terminal 20a of the welding power source 20
When the welding current flows from the other to the other welding current terminal 20b, the welding current flows to the workpieces 146 and 148 as indicated by arrows in FIG.

With this configuration, two upper welding electrodes 504a and 504b can simultaneously perform welding at two locations in one welding operation, thereby improving work efficiency.

In this case, one upper welding electrode 504a is connected to one welding current terminal 20a, and the other upper welding electrode 504b is connected to the other welding current terminal 20b.
One welding current terminal 20a is connected to both upper welding electrodes 504.
a, 504b, and the other welding current terminal 20b may be connected to the lower welding electrode 536.

[0069]

According to the resistance welding apparatus of the present invention, the following effects and advantages can be obtained.

In order to perform welding by pressing the welding electrode while measuring the pressing force of the welding electrode against the workpiece by the pressure detecting means and stopping the displacement of the welding electrode when the pressing force reaches a predetermined value, The management of the length of the welding electrode can be simplified, the welding operation is facilitated, and the number of maintenance steps is reduced. Therefore, work efficiency is improved.

Further, since the rotational force of the motor is converted into linear motion by the cam member and the follower to displace the displacement mechanism, an expensive motor and a ball screw are not required, and the cost of the resistance welding apparatus can be reduced. can do.

Further, when stopping the displacement of the welding electrode,
Since the transmission of the torque of the motor is cut by the clutch and the drive of the cam member is stopped by the brake, the displacement mechanism is prevented from being displaced more than necessary due to the inertia of the motor. It can be stopped instantaneously, and the pressing force of the welding electrode on the workpiece can be accurately controlled.

Further, the operator can set a desired pressing force based on the display on the display means, and the displacement mechanism displaces the welding electrode so as to obtain the set pressing force. be able to. In addition, by displaying the set pressing force and the detected pressing force on the display means, the operator can perform the work while checking the actual pressing force.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a resistance welding apparatus according to an embodiment of the present invention.

FIG. 2 is a side view showing a displacement mechanism of the resistance welding apparatus of FIG.

3 is a longitudinal sectional view showing a clutch brake mechanism used in the displacement mechanism shown in FIG. 2; FIG. 3A is a view showing a state in which a clutch is connected and a brake is released, and FIG. FIG. 5 is a diagram showing a state in which the clutch is disengaged and the brake is applied.

FIG. 4 is a perspective view showing a cylindrical groove cam used in the displacement mechanism of FIG. 2;

FIG. 5 is a longitudinal sectional view showing the displacement mechanism of FIG. 2;

6 is a partially enlarged longitudinal sectional view showing an object to be welded by the resistance welding apparatus of FIG. 1, and FIG. 6A shows a state in which the object to be welded is sandwiched between an upper welding electrode and a lower welding electrode; FIG. 6B is a diagram showing a state where the workpiece is welded.

FIG. 7 is a flowchart illustrating a method of using the resistance welding apparatus of FIG. 1;

FIG. 8 is a flowchart illustrating a method of using the resistance welding apparatus of FIG. 1;

FIG. 9 is a flowchart illustrating another method of using the resistance welding apparatus of FIG. 1;

FIG. 10 is an explanatory diagram of a process according to the flowchart shown in FIG. 9;

FIG. 11 is a timing chart for the processing according to the flowchart shown in FIG. 9;

FIG. 12 is a partially enlarged side view showing a groove cam used in a resistance welding apparatus according to another embodiment of the present invention.

FIG. 13 is a perspective view showing the groove cam of FIG.

FIG. 14 is a partially enlarged side view showing a plate cam used in a resistance welding apparatus according to another embodiment of the present invention.

FIG. 15 is a perspective view showing the plate cam of FIG.

FIG. 16 is a partially enlarged side view showing an end face cam used in a resistance welding apparatus according to still another embodiment of the present invention.

FIG. 17 is a perspective view showing the end cam shown in FIG. 16;

FIG. 18 is a longitudinal sectional view showing a pressing mechanism used in a resistance welding apparatus according to still another embodiment of the present invention.

FIG. 19 is a partially enlarged perspective view showing an upper welding electrode used in the pressing mechanism shown in FIG. 18;

20 is a partially enlarged longitudinal sectional view showing a state where welding is performed on an object to be welded by the pressurizing mechanism of FIG. 18;

[Explanation of symbols]

10, 200, 300, 400 ... resistance welding apparatus 12, 504a, 504b ... upper welding electrode 13, 500 ... pressurizing mechanism 14, 536 ... lower welding electrode 16 ... displacement mechanism 30, 202, 30
2, 404: Motor 32, 204, 304, 406: Clutch brake mechanism 54: Cylindrical groove cam 60: Follower 62: Roller 90, 514a, 514b: Pressure transmitting shaft 120: Strain gauge 146, 148: Work piece 150 ... Nugget 210 ... Groove cam 312 ... Plate cam 412 ... End face cam

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kiyokuni Hagiwara 8-7-3 Shimorenjaku, Mitaka City, Tokyo Inside Seiwa Works Co., Ltd. (72) Inventor Shigeru Yoshida 8-7-3 Shimorenjaku, Mitaka City, Tokyo Stock Seiwa Manufacturing Co., Ltd.

Claims (8)

[Claims] 1. A resistance welding apparatus for performing resistance welding by sandwiching an object to be welded between welding electrodes and energizing the same, wherein a displacement mechanism for displacing one welding electrode with respect to the other welding electrode; A pressurizing force detecting means for detecting a pressurizing force of the welding electrode against an object; and a stop mechanism for stopping the displacement of the one welding electrode, the pressurizing force detected by the pressing force detecting means. A cam member driven by the motor; and a driven member provided on the welding electrode side, engaging with the cam member, and displacing the welding electrode according to the driving of the cam member. A resistance welding apparatus characterized in that: 2. The resistance welding apparatus according to claim 1, wherein said stopping mechanism comprises a brake for stopping driving of said cam member, and a clutch for intermittently connecting said cam member and said motor. Resistance welding equipment. 3. The resistance welding apparatus according to claim 1, wherein the cam member is a cylindrical groove cam formed by forming a groove that is inclined with respect to an axial direction on an outer periphery of a cylindrical member. Characteristic resistance welding equipment. 4. The resistance welding apparatus according to claim 1, wherein the cam member is a groove cam formed by forming a disk member around which a groove portion whose distance from the center of rotation of the disk member changes changes. A resistance welding device characterized by the following. 5. The resistance welding apparatus according to claim 1, wherein the cam member is a plate cam having an outer peripheral surface that changes as the distance from the center of rotation goes around. 6. The resistance welding apparatus according to claim 1, wherein the cam member is an end face cam whose one end surface of a cylindrical member is inclined with respect to the axial direction. . 7. A resistance welding apparatus for performing resistance welding by sandwiching an object to be welded between welding electrodes and energizing the same, comprising: setting means for setting a pressing force of the welding electrode on the object to be welded; Display means for displaying the pressing force; a displacement mechanism for displacing one welding electrode with respect to the other welding electrode; and a pressing force detecting means for detecting a pressing force of the welding electrode on the workpiece. Resistance welding equipment characterized by the above-mentioned. 8. The resistance welding apparatus according to claim 1, wherein the display means displays the set pressure and the detected pressure.