JPH04253579A - Dc resistance welding device - Google Patents

Abstract

PURPOSE:To allow the execution of welding of plural points in a short period of time with simple constitution and to facilitate particularly the operation for exchanging power elements as well as to allow the more efficient execution of the operations for increasing and decreasing welding guns. CONSTITUTION:Units 32a to 32n having a 1st heat sink 30 disposed with transistors Tr 1 to Tr m are selectively attached and detached to and from a 2nd heat sink 34, by which the operations for exchanging the failed transistors Tr 1 to Tr m and the operations for increasing and decreasing the welding guns are efficiently and rapidly executed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct current resistance welding device that has a detachable unit in which a plurality of power elements are arranged.

0002

2. Description of the Related Art In a DC resistance welding device, when a single welding controller sequentially energizes a plurality of welding guns, welding is performed by preparing a plurality of pressure circuits and sequentially closing the welding guns. For this reason, a plurality of independent pressurizing circuits are required, and a simultaneous pressurizing prevention circuit is also required, resulting in a problem that the apparatus becomes complicated. Furthermore, when pressurizing multiple welding guns at the same time and energizing them sequentially,
As shown in Japanese Patent No. 5-92485, a changeover switch is required, which increases the size of the device and causes problems such as a voltage drop.

In this case, in order to solve the above problem, it is conceivable to arrange a current distribution means on the output side of the transformer as disclosed in Japanese Utility Model Application Publication No. 133884/1984. When a current distribution means is provided on the side, there is a problem that the current is large, so the device becomes large and the voltage drop also becomes large.

[0004] Therefore, the present applicant increased the number of transistors in the inverter section of one welding machine and provided the welding timer circuit with a function of switching the transistors every cycle of the inverter section switch period. We have proposed a DC resistance welding device that has a simple configuration and can weld multiple locations in a short time (see Japanese Patent Application No. 2-301354).

[0005]

However, in the above-mentioned technology, it is desired that the transistor as a power element can be replaced more easily in case the transistor is damaged. Furthermore, when the number of welding guns is frequently increased or decreased, there is a risk that the work of increasing or decreasing the number of welding guns becomes complicated, and therefore it is desired to further simplify the work of increasing or decreasing the number of welding guns.

The present invention has been devised in view of this type of problem, and has a simple structure and can perform welding at a plurality of locations in a short time.In particular, it facilitates the work of replacing power elements. Another object of the present invention is to provide a DC resistance welding device that can more efficiently perform the work of increasing and decreasing welding guns.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a plurality of power elements used in an inverter circuit, and a first heat sink that electrically arranges the power elements in series. The heat sink is characterized by comprising a unit and a second heat sink in which a desired number of the units can be selectively arranged.

[0008]

[Operation] In the DC resistance welding apparatus according to the present invention, when replacing the power element, after the unit in which the power element is disposed is separated from the second heat sink,
A unit with a new power element is attached to this second heat sink. Therefore, the power element replacement work can be easily performed. Furthermore, when increasing or decreasing the number of welding guns, it is possible to respond quickly by increasing or decreasing the number of units.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the DC resistance welding apparatus according to the present invention will be described below with reference to the accompanying drawings.

In FIG. 2, reference numeral 10 indicates a schematic configuration of a DC resistance welding apparatus according to this embodiment. This DC resistance welding device 10 includes electrodes 12 and 1 to which three-phase AC supplied from a three-phase AC power source (not shown) is converted into DC and supplied.
4, and a capacitor 16, a multi-inverter section 18, and a snubber circuit 19 are connected between the electrodes 12 and 14. This multi-inverter section 18 converts the direct current supplied from the electrodes 12 and 14 into a predetermined high-frequency alternating current and supplies it to each welding transformer 20. Rectifiers 22a, 22b that convert alternating current to direct current are connected, and these rectifiers 22a, 22
A welding gun 24 is connected to b. This welding gun 24 is connected to a welding electrode 26a via a movable gun arm (not shown).
26b are mounted facing each other.

As shown in FIG. 1, a multi-inverter section 1
8 is a plurality of transistors (power elements) Tr1 to T
rm and a first heat sink 30 in which the transistors Tr1 to Trm are electrically arranged in series, and a second heat sink 34 in which a predetermined number of the units 32a to 32n are arranged in a manner that can be exchanged and increased or decreased. Equipped with. This first heat sink 30 is
It has a rectangular shape, and m transistors Tr1 to Trm are arranged in series on one surface thereof, and radiation fins 36 are formed on the other surface (see FIG. 3). A cooling water passage 38 is formed in the first heat sink 30 in a curved manner and corresponds to the transistors Tr1 to Trm. It has an outlet port 42. The upper side portion 30b of this first heat sink 30 in FIG.
The electrodes 12 and 14 are fixed via a stopper 44,
For these electrodes 12 and 14, transistors Tr1 to T
rm are connected in series.

The second heat sink 34 is provided with a frame member 46, and the electrodes 12, 14 are fixed to one side of the frame member 46. A curved cooling water passage 48 is formed in the second heat sink 34 .
8 has an inlet 50 and an outlet 52 that open at one side of the second heat sink 34 . Grooves 54a to 54n are formed in the surface portion 34a where the units 32a to 32n of the second heat sink 34 are arranged, and grooves 54a to 54n are formed into which the ends of the units 32a to 32n are inserted. Holes 56a, 56 for communicating the inlet 40 and outlet 42 of 30 with the passage 48
b is provided. The holes 56a and 56b contain O.
While the ring 58 is attached, the holes 56a, 5
6b can be freely closed via stoppers 60a and 60b when not in use.

Next, the operation of the DC resistance welding apparatus 10 constructed as described above will be explained. First, three-phase AC supplied from a three-phase AC power supply (not shown) is converted into DC and supplied to the electrodes 12, 14, and then the transistors Tr1 to Tr disposed in the units 32a to 32n constituting the multi-inverter section 18 A high frequency alternating current is derived by the switching operation. And each welding transformer 2
0, a DC voltage is applied to the welding gun 24 via the rectifiers 22a and 22b. This welding gun 24 pressurizes the workpiece W with welding electrodes 26a and 26b under the swinging action of the movable gun arm, and welding is performed on the workpiece W via these welding electrodes 26a and 26b.

In this case, as shown in FIG. 1, cooling water is supplied to the passage 48 from the inlet 50 of the second heat sink 34, and this cooling water flows from the hole 56a through the inlet 40 of the first heat sink 30. The water is supplied to the passage 38, is supplied again to the passage 48 from the outlet 42 and the hole 56b, and is then discharged to the outside from the outlet 52. Further, cooling air is supplied to each first heat sink 30 and air-cooled via the radiation fins 36 provided on the first heat sink 30. Therefore, it is possible to efficiently cool the transistors Tr1 to Trm arranged in each first heat sink 30.

By the way, in this embodiment, the unit 32a
Transistor T placed in any one of 32n to 32n
When any of r1 to Trm is damaged, it becomes possible to deal with it easily and quickly. That is, for example, if any of the transistors Tr1 to Trm provided in the unit 32a is damaged, the unit 32a
After the fasteners 44 fixing the first heat sink 30 and the electrodes 12, 14 constituting the first heat sink 30 are removed, the first heat sink 30 is pulled out along the frame member 46. Next, the first heat sink 30 in which new transistors Tr1 to Trm are arranged is guided along the frame member 46 and inserted into the groove 54a of the second heat sink 34, and the inlet 40 and outlet 42 are connected. Hole 5
6a and the hole 56b. Furthermore, when the first heat sink 30 is fixed via the stopper 44, the electrode 12
, 14 and the transistors Tr1 to Trm are electrically connected in series.

[0016] In this way, by selectively replacing the units 32a to 32n, it is possible to easily and quickly replace desired transistors Tr1 to Trm all at once. Further, when increasing the number of welding guns 24, the units 32a to 32n may be increased in accordance with the increased number of welding guns 24. Here, the plug 6 is provided on the surface portion 34a of the second heat sink 34.
Holes 56a, 56b closed by 0a, 60b
After removing the plugs 60a and 60b from the hole 5,
New first heat sink 30 introduction port 4 at 6a, 56b
0, it is sufficient if the outlet port 42 is communicated. Therefore, it is possible to increase or decrease the number of welding guns 24 extremely efficiently by increasing or decreasing the units 32a to 32n.

[0017]

[Effects of the Invention] According to the DC resistance welding device according to the present invention, the following effects can be obtained.

[0018] The unit in which the power element is arranged is
After being detached from the second heat sink, a unit equipped with a new power element is attached to the second heat sink, making it easy to replace a damaged power element with a new power element all at once. be done. Furthermore, when increasing or decreasing the number of welding guns, it is only necessary to increase or decrease the number of units, and the work of increasing or decreasing the number of welding guns can be performed efficiently and quickly.

[Brief explanation of the drawing]

FIG. 1 is a perspective explanatory view of essential parts of a DC resistance welding device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of the DC resistance welding device.

FIG. 3 is an explanatory plan view of a unit constituting the DC resistance welding device.

[Explanation of symbols]

10...DC resistance welding device 12, 14...electrode 16...Capacitor 18...Multi-inverter section 20...Welding transformer 22a, 22b... rectifier 24...Welding gun 30...Heat sink 32a-32n...unit 34...Heat sink 38, 48...Aisle 40, 50...Inlet 42, 52... Outlet 54a to 54n...Groove portion 56a, 56b...holes

Claims (3)

[Claims] 1. A plurality of power elements used in an inverter circuit, and a first power element in which the power elements are electrically arranged in series.
A direct current resistance welding device comprising: a unit having a heat sink; and a second heat sink in which a desired number of the units can be selectively arranged. 2. The DC resistance welding apparatus according to claim 1, wherein the first and second heat sinks are provided with cooling water passages. 3. The DC resistance welding apparatus according to claim 1, wherein the second heat sink includes an electrode that is electrically connected to the power element of the unit when the unit is placed.