JPH0747224B2 - Resistance welder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resistance welding machine using an electrode tip, and more particularly to improving maintenance of an electrode tip.

(Prior Art) FIG. 2 shows the structure of a typical conventional resistance welding machine.

When compressed air is sent to the air cylinder 100 and the piston rod 102 descends, the pressure holding plate 112 descends via the pressure slide rod 106, the cross roller guide 108, and the pressure guide 110, and the spring pressing member 114 compresses. The coil spring 116 is pressed downward. As a result, the upper arm 118 that receives the lower end of the spring 116, the upper electrode holder 120, and the upper electrode tip 122.
Are integrally lowered, and the materials to be welded 128 and 130 are sandwiched between the lower electrode tip 124 and the lower electrode tip 124 to start pressing.

When the applied pressure reaches a specified value, the micro switch
134 is turned on, and in response thereto, the welding control circuit (not shown) starts energization, and the welding current from the welding power supply circuit (not shown) passes through the electrode tips 122 and 124 and the workpiece 12 is welded.
Then, the welded portion is heated and melted by Joule heat, and when the energization is cut off, a nugget is generated after cooling for a predetermined time and welding is completed.

In addition, 140 is a stopper member that receives the pressure slide rod 106, and 142 and 144 are an upper feeder and a lower feeder for supplying a welding current.

(Problems to be Solved by the Invention) As described above, since high pressure and high temperature are applied to the electrode tips 122 and 124 during resistance welding, the tip end portion is crushed and deformed as the number of times of welding is increased. If this happens, the welding pressure and the welding current will deviate from the set values, causing poor welding. In addition, plating of the material to be welded or oil may adhere to the tip of the tip, and in that case also, the welding current fluctuates due to electrodeposits and dirt, resulting in poor welding.

Therefore, it is necessary to polish or dress the tips of the electrode tips 122, 124 at an appropriate time.In the past, therefore, the welding operation was interrupted, and the operator manually brushed the electrode tips 122, 124 with a hand or applied a die to polish. It is carried out.

However, interruption of the welding work leads to a reduction in work efficiency, and manual polishing work makes maintenance of the electrode tip cumbersome and costly.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a resistance welding machine that automates maintenance and management of electrode tips and improves welding work efficiency.

(Means for Solving Problems) In order to achieve the above object, the resistance welding machine of the present invention is
In a resistance welding machine that performs resistance welding by applying an electric current while pressing an electrode tip on a material to be welded, an indexing mechanism that intermittently rotates an indexing table at a predetermined angle, and a predetermined indexing table on the indexing table. Tip supporting means which are arranged at intervals and which respectively support the electrode tips, pressurizing means for applying a pressure force to the material to be welded through the electrode tips at the first station of the indexing table, Welding current supply means for supplying a welding current to the material to be welded through the electrode tip at the first station, and the electrode tip at the second station other than the first station of the indexing table. Tip polishing means for polishing the tip and the electrode chuck at a third station other than the first and second stations of the indexing table. A tip height detecting means for detecting a height of the electrode tip, and an alarm output means for outputting an alarm when the height of the electrode tip is lower than a reference value based on an output signal of the tip height detecting means. It was configured to do.

Further, in the resistance welding machine of the present invention, the tip supporting means movably supports the electrode tip on the indexing table in a predetermined direction substantially parallel to the table surface, and the pressing means supports the tip supporting means. The electrode tip is driven in the predetermined direction via the.

(Operation) When the tip of the electrode tip used so far in the first station is deformed or soiled, the indexing table is rotated by a predetermined angle during the resistance welding.

Then, another electrode tip whose tip tip has been finely polished or shaped by the tip polishing means comes to the first station, and this electrode tip is used for the subsequent resistance welding. This tip change is automatic and does not require interruption of the welding operation.

On the other hand, the consumable electrode tip transferred from the first station to the second station by the rotation of the indexing table is
The tip of the tip is abraded by the tip abrader.
This polishing operation is performed automatically without affecting the welding operation of the first station. Further, the tip height of the polished electrode tip transferred from the second station to the third station by the rotation of the indexing table is detected by the tip height detecting means. The output signal of the chip height detecting means (chip height information) is sent to the alarm output means. When the chip height inspected by the chip height detecting means is lower than the reference value, the alarm output manual output an alarm to prompt the adjustment of the chip height. Thus, the electrode tip having the cleaned tip end and the proper tip height is sent to the first station again by the rotation of the indexing table.

The tip supporting means movably supports the electrode tip on the indexing table in a predetermined direction substantially parallel to the table surface, and the pressing means drives the electrode tip in the predetermined direction via the tip supporting means. With the configuration, only the tip supporting means and the electrode tip need to be pressure-driven while the indexing table is fixed, and the mechanism of the pressure-applying means can be downsized, which in turn reduces the overall size and cost of the welding machine. You can

(Embodiment) FIG. 1 shows a main part of a resistance welding machine according to an embodiment of the present invention. This resistance welder consists of a pair of electrode tips (upper,
This is a direct type resistance welding machine that applies pressure and welding current while sandwiching the material to be welded with the lower electrode tip).

In this embodiment, as shown in the drawing, four upper chips are arranged on the upper indexing table 10 at intervals of 90 °.
Holders UH1 to UH4 each have four upper electrode tips UC1 to U
As shown in the figure, C4 is supported substantially parallel to the surface of the table 10 and in the radial direction of the table 10 so as to be movable in the same direction, while being arranged at a 90 ° interval on the lower indexing table 30. The four lower electrode holders LH1 to LH4 provided respectively support four lower electrode chips LC1 to LC4.

Both indexing tables 10 and 30 arranged so that the respective table surfaces are orthogonal to each other are driven by the motors 18 and 38, respectively.
It has a four-position (station) type structure in which it rotates intermittently every 90 ° around 0, 40, and a positioning mechanism is housed in the boxes 22, 42 on the back side of the table.

Welding station The lower station of the upper indexing table 10 and the left station of the lower indexing table 30 are welding stations SW.
Then, the upper and lower electrodes (UC1, LC1 in the illustrated state) coming here are used for resistance welding. The welding station SW is provided with a pressurizing device 50 and a welding current supply device 60, and resistance welding is performed by the following operation.

The pressurizing device 50 uses an air cylinder 52 as a driving source, and when the piston 54 descends due to the operation of the air cylinder 52, the spring pressing member 56, the compression coil spring 58, and the arm 62 descend, and the tip portion 6 of the arm 62.
2a contacts the upper end surface 12 of the tip holder UH1 and presses the tip holder UH1 downward. This allows the tip holder U
The H1 slides downward along the guide 16 against the tension coil spring 14, and finally, the materials to be welded 24 and 26 are sandwiched between the upper electrode tip UC1 and the lower electrode tip LC1. When the piston 54 further descends, the compression coil spring 58 elastically deforms and the welded material 24, 26 passes through both electrode tips UC1, LC1.
A pressing force is applied to the micro switch (not shown) when it reaches a predetermined value, and in response to this, a welding current is supplied from the welding current supply device 60 to the materials to be welded 24 and 26.
In this embodiment, each upper electrode tip U is attached to each upper tip holder UHi (i = 1 to 4) arranged on the upper indexing table 10.
Ci (i = 1 to 4) is supported substantially parallel to the table surface and in the radial direction of the table so as to be movable in the same direction. At the welding station SW, the pressurizing device 50 has the upper tip holder UHi.
Since the upper electrode tip UCi is pressure-driven via the, the upper indexing table 10 may remain fixed, that is, it is not necessary to be driven together with the upper electrode tip UCi. As a result, the pressurizing device 50 has a small size,
As a result, the entire welding machine is compact and low-cost.

The welding current supply device 60 includes a welding power supply circuit (not shown),
It is composed of an arm 62 connected to it, a feeding unit 64, and upper and lower chip holders UH1 and LH1. In other words, when energized, welding power supply circuit → arm 62 → upper tip holder UH
1 → Upper electrode tip UC1 → Welding material 24,26 → Lower electrode tip LC1 → Lower tip holder LH1 → Feed bar 64 → Welding current flows in the closed circuit of the welding power supply circuit. The power supply bar 64 is brought into contact with the lower surface of the lower tip holder LH1 by driving the air cylinder 66.

In this way, electricity is supplied for a predetermined time, then cooling is carried out, one resistance welding is completed, and the air cylinders 52, 66 are restored. After that, the material to be welded 24, 26 or the welding point is replaced with a new one, and then resistance welding having the same operation as described above is repeated.

Polishing Stations The upper stations of the upper indexing table 10 and the right stations of the lower indexing table 30 are polishing stations SUG and SLG, respectively, and chip polishing devices 70 and 80 are provided therein.

In these tip polishing devices 70, 80, donut-shaped rotating brushes 74, 84 are attached to the tips of the rotating shafts of the motors 72, 82, and they are rotated to make electrode tips (UC3, LC3 in the state shown).
Polish the tip of. The air cylinders 76,86 are the motors 72,82.
Guide the supports 78 and 88 along the arrows 79 and 89 along the arrows C1, C0,
In the forward movement state shown in the drawing, the rotary brushes 74, 84 have advanced to the polishing stations SUG, SLG.

As described above, in the present embodiment, the electrode tips are automatically (mechanically) polished at the stations SUG and SLG apart from the welding station SW independently of the welding operation.
There is no need to interrupt the welding operation, and no manpower is required for polishing.

Chip Height Detecting Station As shown, a chip height detecting station SLH is provided between the polishing station SLG and the welding station SW of the lower indexing table 30. Here, the electrode tip whose tip tip was polished and lowered (in the state shown in the figure,
The position sensor 90 detects the chip height of LC4) and sends the height information to the control unit 94. When the chip height is lower than the reference value, the control unit 94 outputs an alarm signal.
Issue AR and encourage adjustment. Then, when the electrode tip LC4 is next moved to the welding station SW, resistance welding is performed at an appropriate tip height.

Although not shown, the upper indexing table 10 also has a chip height detection station SUH similar to the above between the polishing station SUG and the welding station SW.

System Control The control of each part of the apparatus described above is performed by the control unit 94. The control section 94 operates each section of the apparatus in sequence control in response to a tip replacement instruction signal KG from a resistance welding control apparatus (not shown).

That is, first, the motors 18 and 38 are operated to rotate both indexing tables 10 and 30 by 90 ° to move each electrode tip to the next station.

As a result, at the welding station SW, the tip of the tip is finely polished and the height is appropriate (eg UC4, LC
4) comes and resistance welding continues uninterrupted by means of the pressure device 50 and the welding current supply device 60 using these electrode tips.

On the other hand, in the polishing stations SUG and SLG, electrode tips whose tip ends are deformed or contaminated by a large number of weldings (for example, UC
2, LC2), and the chip polishing devices 70, 80 polish these electrode chips. At this time, the control unit 94 operates the air cylinders 76, 86 to move the rotating brushes 74, 84 to the polishing stations SUG, SLG, respectively, and also operates the motors 72, 82 to move the rotating brushes 74, 84, respectively. Rotate.

Further, the control unit 94 controls the chip height detection stations SUH, S
The height information is fetched from the LH position sensors 90 and 92 and the inspection result is output.

Note that the tip welding instruction signal KG from the resistance welding control device
Is when a non-energized accident occurs (that is, when it is determined that the tip of the tip has become dirty and current stops flowing), or when the preset number of times of welding has been reached (that is, the tip of the tip has been determined to be considerably rounded). (In the case), it is given to the control unit 94.

Although one embodiment of the present invention has been described above, it is understood that the present invention is by no means limited thereto.

For example, the number of tip holders UHi and LHi arranged on the upper and lower indexing tables 10 and 30 and the electrode tips U, respectively.
The number of Ci and LCi is not limited to four as in the above embodiment, and any number can be used.

Further, the tip polishing apparatus may be of various types other than the rotary brush type as described above, and a polishing apparatus for not only simply polishing the tip of the tip but also shaping it is also suitable.

Further, although the above-mentioned embodiment relates to the direct resistance welding machine, the present invention is also applicable to an indirect resistance welding machine using only one electrode tip, and in that case, 1 It is possible to finish with one indexing table.

(Effects of the Invention) As described above, according to the resistance welding machine of the present invention, the exchange and polishing of the electrode tip are automated, and the height of the electrode tip is automatically inspected to obtain an appropriate tip height. Since the electrode tip that it has is used again for resistance welding, it is not necessary to interrupt the welding work for maintenance of the electrode tip, and manual polishing work is not required, resulting in a significant improvement in welding work efficiency. It Also,
The tip supporting means movably supports the electrode tip on the indexing table in a predetermined direction substantially parallel to the table surface, and the pressing means drives the electrode tip in the predetermined direction via the tip supporting means. With the configuration, only the tip support means and the electrode tip need to be pressure-driven while the indexing table is fixed, which makes the mechanism of the pressure means smaller, which in turn reduces the overall size and cost of the welding machine. can do.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a main configuration of a resistance welding machine according to an embodiment of the present invention, and FIG. 2 is a side view showing a structure of a conventional typical resistance welding machine. In the drawing, 10 ... upper indexing table, 30 ... lower indexing table, 18,38 ... motor, 50 ... pressurizing device, 60 ... welding current supply device, 70, 80 ... chip polishing device, 94 …… Control part, UC1 to UC4 …… Upper electrode tip, LC1 to LC4 …… Lower electrode tip, UH1 to UH4 …… Upper tip holder, LH1 to LH4 …… Lower tip holder.

Claims (2)

[Claims] 1. A resistance welding machine for performing resistance welding by applying an electric current to a material to be welded while applying pressure thereto, and an indexing mechanism for intermittently rotating an indexing table at a predetermined angle; Tip supporting means arranged on the table at predetermined intervals for supporting the electrode tips, respectively, and a pressing force for applying a pressure force to the material to be welded through the electrode tips at the first station of the indexing table. A pressure means, a welding current supply means for supplying a welding current to the material to be welded through the electrode tip at the first station, and a second portion of the indexing table other than the first station.
And a tip height for detecting the height of the electrode tip at a third station of the indexing table other than the first and second stations. A resistance welding machine, comprising: a detection unit; and an alarm output unit that outputs an alarm when the height of the electrode tip is lower than a reference value based on the output signal of the tip height detection unit. . 2. The tip supporting means movably supports the electrode tip on the indexing table in a predetermined direction substantially parallel to the table surface, and the pressurizing means supports the electrode via the tip supporting means. The resistance welding machine according to claim 1, wherein the tip is configured to be driven in the predetermined direction.