JPH0361550B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present description relates to a welding current energizing device for a resistance welding machine.

<Conventional technology> For example, when performing continuous welding work by moving a spot welding gun lightly and freely using the spatial movement of the operating arm of an industrial robot, it is necessary to connect the spot welding gun and welding transformer. In order to prevent the inertia of the thick secondary cable from directly interfering with the movement of the welding gun, and to avoid shortening the life of the secondary cable, the spot welding gun is connected to the tip of the operating arm via an articulated current-carrying device. is being installed.

Heretofore, some typical examples of this type of energizing device include Japanese Patent Application Laid-Open No. 52-176086 (hereinafter referred to as the A invention), Japanese Utility Model Publication No. 52-56357 (hereinafter referred to as the B invention), and Publication No. 52-189980 (hereinafter referred to as C design) has been proposed.

In the above invention A, a pair of positive and negative power supply plates called contact segments are fixed between a welding transformer and a spot welding gun, and the other contact segment is movable in the axial direction as a power receiving plate. is pressed from the inside by a spring or the like, and an actuating device moves the power receiving plate from the inside to the outside to bring the receiving and power receiving plates into close contact with each other to form an energizing circuit.

On the other hand, in the B design, a pair of positive and negative power receiving plates is fixed to the S axis that supports the welding gun, a pair of positive and negative power receiving plates is inserted between the power receiving plates, and a pressurizing chamber is provided between the power feeding plates. The pressure fluid in the pressure chamber presses the power supply plate against the outer power receiving plate, and at the same time, the pressure fluid is used to clean the mutual contact surfaces of the receiving and power supply plates.

In addition, the C design has an S axis that supports the welding gun.
A pair of positive and negative power supply plates and a pair of positive and negative power receiving plates are rotatably fitted through the insulating plates, and the pair of receiving and power supply plates are clamped by a cylinder that works with a pressure cylinder to create a welding gun. A current-carrying circuit is formed only when pressure is applied.

All of the conventional devices described above have been proposed as energizing devices that function as wrist joints of welding guns for industrial robots.

<Problems to be solved by the invention> However, invention A, B, and C described above
Both ideas have the following common drawbacks.

Since the power receiving plate or the power feeding plate must be moved in the axial direction by the cylinder mechanism and the contact power feeding surfaces between them must be brought into close contact with each other, it is necessary to provide a play distance between the power receiving plate and the power feeding plate, and the contact surface Small foreign matter such as dust can easily enter between the two, and countermeasures are a problem.

The conductor connected to the receiving/powering board must be made of a copper plate with flexibility that can follow the relative movement of the receiving/powering board, which has a large impact on cost. .

In conventional devices, pressure is applied between the power receiving and power feeding plates, so due to the structure, power is supplied by having the relatively wide, flat power feeding surfaces in full contact with each other. Difficult to reduce size and weight.

<Means for Solving the Problems> Therefore, the present invention provides a conductive shaft 12 that is fixed in position between the mounting plate 14 on the driving side and the mounting plate 4 on the welding gun side. , a pair of positive and negative terminal plates 1 are inserted into the inner diameters of a pair of positive and negative external connection conductors 21 and 22 and can move together with the conductive shafts thereof.
5, 16 are installed, and these terminal boards 15,
16 and the external connection conductors 21 and 22, an annular cylinder chamber 30 is formed that faces the terminal plate in the circumferential direction, and this cylinder chamber has an axial direction C of the conductive shaft 12. A pair of pressurizing rings 33, 33' that can be moved relative to each other by fluid pressure at C, and applying pressure between the positive and negative external connection conductors and each terminal board in response to the pressing force of the pressurizing rings; To provide a joint power supply unit for a resistance welding machine, which includes contactors 31 and 32 having pressure surfaces in close contact with each other.

<Function> Therefore, in the power supply unit of the present invention, a set of ring-shaped positive and negative contactors is installed in a cylinder chamber formed between the terminal plate of each set of positive and negative terminals and an external connection conductor, and With air at the appropriate pressure supplied to the contactor, each contactor connects a pair of external connection conductors and the corresponding terminal board to form a reciprocating path for welding current. Rather than moving the plates to make two-dimensional contact with each other, local contact can be made inside the cylinder chamber that is sealed from the outside air, so it is possible to prevent foreign substances such as dust from entering the contact power supply section. In addition, it can be made lighter and more compact, and the external connection conductor can be attached regardless of the movement of the welding gun. Instead of using such expensive materials, they can be replaced with cheaper materials such as rigid materials.

<Example> Hereinafter, an example of the present invention will be described based on the drawings.

Figure 1 shows an example in which the joint power supply unit according to the present invention is applied to the wrist joint of the arm of a spot welding robot. This device is attached to the shaft.

Needless to say, the robot body 1 can be of any type, such as an articulated arm type or a polar coordinate type. The welding gun 2 is rotatably supported by a mounting plate 4 fixed to the S-axis joint at the tip of the arm 3 by a common shaft of two gun arms 5 and 6, and one gun arm 6 is attached to a pressurizing cylinder. 7, and the other gun arm 5 is connected to the cylinder rod, respectively, and opposing electrode tips 8, 9 are attached to the tips of the gun arms 5, 6.

The welding cable 11 is connected from a welding transformer (not shown) to the S-axis joint power supply unit 10. A pair of positive and negative flexible connecting conductors 13,
13'.

FIG. 2 is a sectional view of a main part of the apparatus of the present invention, and FIG. 3 is a view taken along the line A--A in FIG.

The power supply unit 10 of this device is removably fixed with bolts or the like between a drive-side mounting plate 14 fixed to the tip of the operating arm 3 of the robot and a mounting plate 4 supporting the welding gun 2. . A pair of positive and negative terminal plates 15 and 16, which are electrically insulated from each other, are attached to the conductive shaft 12 of this device. These terminal plates include outer ring plates 15a and 16a located at both ends of the conductive shaft 12, and outer ring plates 15a and 16a, respectively.
Inner ring plates 15b and 16b located inside 6a, respectively.
It is composed of a combination of and.

In this embodiment, one outer ring plate 15a is formed integrally with the conductive shaft 12, and the other outer ring plate 16a and the inner ring plates 15b and 16b are both formed with shaft holes, in which the conductive shaft 12 is formed. inserted. In the inner ring plate 15b corresponding to the outer ring plate 15a, the inner surface of the shaft hole is in close contact with the outer surface of the conductive shaft, and an O-ring 17 is provided on the side facing the outer ring plate 15a to maintain airtightness between the inner ring plate 15b and the outer ring plate 15a. held and electrically connected.

On the other hand, the outer ring plate 16a and the corresponding inner ring plate 1
6b is inserted onto the insulating tube 18 fitted into the conductive shaft 12 and is electrically insulated from the conductive shaft 12. And the inner ring plate 16b facing the outer ring plate 16a
An O-ring 17 is interposed on the side surface of the inner ring plate 16.
b and the outer ring plate 16b are kept airtight and electrically connected. In addition, the inner ring plate 15
An insulating partition wall 18' is inserted between b and 16b,
The inner ring plates are electrically insulated from each other.

The inner ring plates 15b and 16b inserted between the outer ring plates 15a and 16a are lower than the outer ring plates, and an annular groove along the outer periphery of the inner ring plate is formed between the outer ring plates 15a and 16a. Thrust washers 19, 19' are fitted into the annular grooves on the side surfaces of the outer ring plates 15a and 16a, and a pair of positive and negative external connection conductors 21, 22, which are separably combined via an insulating partition 20, are inserted into the annular grooves. Sealing material 23, 23 facing between thrust washers 19, 19'
It is inserted into the outer periphery of the inner ring plates 15b, 16b with . These external connection conductors 21 and 22 are connected to a secondary cable 2 connected to a welding transformer (not shown).
It is removably attached to the reciprocating terminals 25 and 26 of No. 4 via relay conducting plates 27 and 28 with bolts B1 and B2.

An annular cylinder chamber 30 is formed inside the positive and negative pair of external connection conductors 21 and 22 facing the outer periphery of the inner ring plates 15b and 16b, and this cylinder chamber is formed in the external connection conductors 21 and 22. It communicates with the air hole 29 of. In this cylinder chamber 30, a pair of positive and negative contactors 31 and 32 are installed on the outer circumferential surface of each inner ring plate 15b and 16b for electrically connecting the outer ring plates of each pair. There is. In addition, the cylinder chamber 30 is constantly energized with air pressure sufficient to maintain the position of the contactor, or the contactor is moved against the inner wall of the cylinder by the force of air pressure that acts in conjunction with the pressurizing cylinder of the welding gun only when pressurizing the electrode. and each inner ring plate 15b,
A pair of contactors 31 and 32 are pressed in the axial direction C-C of the conductive shaft 12 to the outer circumferential surface of the conductor 16b and one side of the external connection conductors 21 and 22, and are electrically connected by pressurization and close contact. Pressure rings 33, 33' are provided.

The above-mentioned contactors 31 and 32 are divided into a plurality of pieces, and the divided power feeding pieces are collected in a ring shape, and are usually manufactured from a sintered metal material. Each pressure ring 33, 33' is made of, for example, an insulating synthetic resin material, and has a tapered surface for pressing the contactors 21, 22. The power feeding piece pressed by this tapered pressure surface has inner ring plates 15b, 16
The force of pressing against the outer circumferential surface of b and the force of pressing against the side surfaces of the external connection conductors 21 and 22 forming the inner wall of the cylinder act equally.

Inside each inner ring plate 15b, 16b, annular cooling holes 34, 35 are opened in the circumferential direction.
The cooling water flow holes 34, 35 are communicated with cooling water flow holes 36, 37 to the inlet P1 and out port P2 formed in each of the outer race plates 15a, 16a through the insulating partition wall 18'.

A pair of positive and negative terminal boards 1 obtained in this way
5 and 16, six common bolt holes 38... and two positioning pin insertion holes 39... are bored in the circumferential direction of the conductive shaft 12 in each inner and outer ring plate,
The power supply unit 10 of this device is connected by bolts 40 and positioning pins 41 that are inserted into common bolt holes 38 and insertion holes 39 along with each mounting plate 4 and 14.
is removably attached.

The operation of the present invention will be explained using the above configuration.
The spot welding gun 12 moves as instructed by the movement of the operating arm of the robot and the S-axis articulating power supply unit 10, and performs a predetermined work.

During welding, the gun arms 5 and 6 are rotated by the pressure cylinder 7, and the electrode tips 8 and 9 are rotated.
Pressurize the workpiece by pressing each pressure ring 33, 33'.
When a welding current is passed through the contactors 31 and 32 while pressing each contactor 31 and 32, the welding current flows from one terminal 25 of the secondary cable 24 connected to the welding transformer to the connecting conductor 21, and the contactor 3
1, flows to the inner ring plate 15b, flows from the conductive shaft 12, passes through the flexible connecting conductor 13, passes through the gun arm 5, and flows between the electrodes 8, 9. The current flowing through the welding gun is transmitted from the gun arm 6, the flexible connecting conductor 13' to the outer ring plate 16a,
Then, it flows to the inner ring plate 16b, passes through the contactor 32, passes through the external connection conductor 22, and the other terminal 26 of the secondary cable 24, and returns to the welding transformer.

On the other hand, when the welding gun rotates, the conductive shaft 12 and the pair of positive and negative terminal plates 15, 16 rotate together in accordance with the rotation of the drive side mounting plate, and the inner ring plate 15b,
16b is the horizontal surface of the contactors 31, 32 and the thrust washers 19, 19', and the outer ring plate 15a,
16a slide on the vertical surfaces of the thrust washers.

In addition, in this embodiment, the case where the power supply unit of the present invention is used in the joint part of the S axis has been explained, but the essence of the present invention is not limited to this, and the power supply unit of the present invention is used in the joint part of the S axis. Needless to say, it can be used for joints.

<Effects of the Invention> As described above, according to the present invention, a pair of ring-shaped positive and negative contactors is installed in a cylinder chamber formed between each pair of positive and negative terminal plates and an external connection conductor,
Furthermore, each contactor connects a pair of connecting conductors and their corresponding terminal plates using the pressure of the air supplied into the cylinder chamber, forming a reciprocating path for welding current. Rather than moving the power supply plates to each other and making them contact each other flatly,
Since it is possible to make local contact within the cylinder chamber that is sealed from the outside air, it is possible to prevent foreign matter such as dust from entering the contact power supply unit, thereby further extending the life of the indirect power supply unit. Moreover, it is lightweight and compact, and there is no need to use expensive materials such as flexible copper plates for the external connection conductor that connects the receiving and feeding boards as in the past.
An inexpensive external connection conductor such as a rigid material can be attached regardless of the movement of the welding gun.

[Brief explanation of drawings]

FIG. 1 is an overall perspective view of a spot welding robot in which the device of the present invention is applied to the joints of the spot welding robot. FIG. 2 is a sectional view of essential parts of the device of the present invention. FIG. 3 is a view taken along the line A-A in FIG. Figure 4 is the second
BB arrow view of the figure. <Explanation of symbols>, 4...Mounting plate on the welding gun side,
12... Conductive shaft, 14... Drive side mounting plate, 1
5, 16... A pair of positive and negative terminal boards, 21, 22...
External connection conductor, 30...Cylinder chamber, 31, 32
...A pair of positive and negative contactors, 33, 33'...Pressure ring.

Claims (1)

[Claims] 1 Mounting plate 14 on the drive side and mounting plate 4 on the welding gun side
A conductive shaft 12 is fixed in position between the conductive shaft and a pair of positive and negative external connection conductors 21, 2
A pair of positive and negative terminal plates 15 and 16 are installed which can be inserted into the inner diameter of the conductor 2 and move together with the conductive shaft thereof, and these terminal plates 15 and 16 and the external connection conductor 2
1 and 22, an annular cylinder chamber 30 is formed that faces the terminal plate in the circumferential direction, and this cylinder chamber receives fluid pressure in the axial direction C-C of the conductive shaft 12. A pair of pressurizing rings 33, 33' that can be moved relative to each other, and the pressing force of the pressurizing rings applies pressure between the positive and negative external connection conductors and each terminal board, thereby creating a pressurizing surface that comes into close contact with each other. A joint power supply unit for a resistance welding machine, which has contactors 31 and 32 installed therein.