JPS61216870A - Feeding unit to joint of resistance welder - Google Patents

Abstract

PURPOSE:To prevent the invasion of foreign matters into the connection part and to liberate the revolution of a welding gun with light weighed and compact mechanism by fitting the terminal plate at welding gun side to the circular hole of the connecting conductor at the external part of the feeding unit and by conducting with the annular pressure contactor provided inside the composed cylinder chamber. CONSTITUTION:The terminal plates 15, 16 of a welding gun 2 are fitted via thrust washers 19, 19' in the insulated state respectively to the circular hole of the external part connecting conductors 21, 22 of the feeding unit 10, which are insulated 20 each other and connected to the terminals 25, 26 of the secondary cable 24. The annular contactor 31, 32 made of sintered metal inside the cylinder chamber 30 composed of the both connects the external part connecting conductors 21, 22 and terminal plates 15, 16 to be electrified respectively with the taper face pressure of the pressing rings 33, 33' by air pressure 29. Gun arms 5, 6 are respectively connected to the conductive shaft 12 of the terminal plate 15a and the terminal plate 16a via flexible connecting conductors 13, 13'. The invasion of foreign matters to the connection part is prevented and the revolving drive of the welding gun is liberated by the feeding unit 10 of light-weight and small size.

Description

[Detailed description of the invention] (Industrial application field) This 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 In order to prevent the inertia of the thick secondary cable that connects the cable from directly interfering with the movement of the welding gun, and to prevent shortening the life of the secondary cable, an articulated current-carrying device is installed at the tip of the operating arm. Installing a spot welding gun is being carried out.

Heretofore, some representative current-carrying devices of this type are disclosed in Japanese Unexamined Patent Publication No. 176086/1986 II! (hereinafter referred to as invention A), Japanese Utility Model Publication No. 52-56357 (hereinafter referred to as invention B), and Publication of Utility Model Publication No. 5'2-189980 (hereinafter referred to as invention C).

In the above invention A, a pair of positive and negative power feeding plates called contact segments are fixed between the welding transformer and the 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 feeding plates is inserted between the power receiving plates, and a pressurizing chamber is provided in the middle of the 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, in the C design, a pair of positive and negative power supply plates and a pair of positive and negative power receiving plates are rotatably inserted into the S axis that supports the welding gun through an insulating plate. A cylinder interlocked with the pressure cylinder applies pressure to form an energizing circuit only when the welding gun is pressurized.

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

(Problems to be Solved by the Invention) However, invention A and both inventions B and C described above have the following common drawbacks.

■It is necessary to move the power receiving plate or the power feeding plate in the axial direction using a cylinder mechanism so that the contact power feeding surfaces between them are in close contact with each other, so it is necessary to provide a play distance between the power receiving plate and the power feeding plate, It is easy for small foreign objects such as dust to get in between, and countermeasures become a problem.

■For the conductor connected to the receiving/power supply board, it is necessary to use a flexible copper plate that can follow the relative movement of the receiving/power supply board, which has a large impact on cost. .

■In conventional devices, pressure is applied between the receiving and feeding plates, so due to their structure, the relatively wide, flat feeding surface must be in full contact with each other to transfer power. ,
It is difficult to make it smaller and lighter.

Means for Solving the Problem> ′ Therefore, in the present invention, a conductive shaft is fixed in position between the mounting plate on the driving side and the mounting plate on the welding gun side, and the conductive shaft has a positive and negative polarity. A pair of positive and negative terminal boards are installed that penetrate the inner diameter of the set of external connection conductors and can move together with their conductive shafts, and between these terminal boards and the external connection conductors,
An annular cylinder chamber facing each other on the circumference of the terminal plate is formed, and this cylinder chamber includes a pair of pressurizing rings that can mutually move outwardly using fluid pressure, and a pressurizing ring that can be pressed against the pressurizing rings. A joint power supply unit for a resistance welding machine is equipped with a ring-shaped contactor that electrically connects each set of positive and negative external connection conductors and each terminal board so that it can be moved by pressure. provide.

Therefore, in the power supply unit of the present invention, a pair of ring-shaped positive and negative contactors is installed in a cylinder chamber formed between the terminal plate of each pair of positive and negative terminals and an external connection conductor, and the power supply unit is provided with a ring-shaped contactor that is supplied into the cylinder chamber. Since each contactor connects a pair of external connection conductors and their corresponding terminal plates using air at an appropriate pressure, forming a reciprocating path for the welding current, it is possible to Rather than moving them and bringing them into contact on a flat surface, local contact can be made inside the cylinder chamber that is sealed from the outside air, which prevents foreign matter such as dust from entering the contact power supply section. , it can be made even lighter and more compact, and the external connection conductor can be attached regardless of the movement of the welding gun, making it possible to use an expensive flexible copper plate for the external connection conductor that connects the conventional receiving and power supply plates. Even if you do not use a rigid material, you can replace it with an inexpensive material such as a rigid material.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 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 interlock at the tip of the arm (3) by a common shaft portion of the two gun arms (5) and (6). One gun arm (5) is fixed to the main body of the pressurizing cylinder (7), and opposing electrode tips (8) and (9) are inserted into the tips of the gun arms (5) and (6). be.

A welding cable (11) is connected from a welding transformer (not shown) to an S-axis joint power supply unit (10). A pair of positive and negative flexible connecting conductors (13) (13) are connected between the S-axis power supply unit (10) and the welding gun (2), respectively.
are connected via.

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 a bolt between the drive-side mounting plate (14) fixed to the tip of the robot's operating arm (3) and the mounting plate (4) that supports the welding gun (2). etc., and is removably fixed. 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. However, these terminal plates consist of outer ring plates (15a) (16a) located at both ends of the conductive shaft (12), and outer ring plates (15a).
Inner ring plates (15b) located inside (16a) (
16b).

In this embodiment, one outer ring plate (15a) is formed integrally with the conductive shaft (12), and the other outer ring plate (16) is formed integrally with the conductive shaft (12).
a) and the inner ring plates (15b) and (16b) each have a shaft hole formed therein, into which the conductive shaft (12) is inserted.

The inner ring plate (15b) corresponding to the outer ring plate (15a) has the inner surface of its shaft hole in close contact with the outer surface of the conductive shaft, and
The outer ring plate (15a) is electrically connected to the outer ring plate (15a) through an O-ring (17) on the side facing the outer ring plate (15a).

On the other hand, an outer ring plate (16a) and a corresponding inner ring plate (16a)
b) 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 (15b
) and (lflib), an insulating partition wall (18) is inserted to electrically insulate the inner ring plates 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 the inner ring plates (15b) and (16b) are inserted between the outer ring plates (15a) and (16a). An annular groove is formed along the outer circumference of the plate, and thrust washers (19) (19) are fitted into the annular groove on the side surfaces of the outer ring plates (15a) and (16a). ) A pair of positive and negative external connection conductors (21) (22) which are divisibly combined through the thrust washers (9) (19) face between the thrust washers (9) (19), and the sealing material (23) (
23) are inserted into the outer peripheries of the inner ring plates (15b) and (16b). This external connection conductor (21) (22
) is a relay conductor plate (2
7) It is removably attached with bolts etc. (B1) (B2) via (2B).

An annular cylinder chamber (30) is formed inside the positive and negative pair of external connection conductors (21, 22) facing the outer peripheries of the inner ring plates (15b, 16b). The external connection conductors (21) and (22) are communicated with air holes (29) formed therein. In this cylinder chamber (30), one set of positive and negative contactors (for electrically connecting the outer ring plates of each set of positive and negative pairs) (
31) (32) are installed on the outer peripheral surface of each inner ring plate (15b) (16b). In addition, this cylinder chamber (30) is moved against the inner wall of the cylinder by the force of pneumatic pressure that is constantly energized or acts in conjunction with the pressurizing cylinder of the welding gun only when the electrode is pressurized, and each inner ring plate ( 15b)
(16b) outer peripheral surface and external connection conductor (21) (22)
A pair of pressure rings (33) (33) are provided on the -side surfaces of the contactors (31) (32) to press each contactor (31) (32) from the inside to the outside to bring them into electrical contact.

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 pressurizing ring (33) (aj) is made of, for example, an insulating synthetic resin material, and is connected to the contactor (2).
1) The surface that presses (22) is formed in a tapered shape. The power feeding piece pressed by this tapered pressure surface has a force pressing against the outer peripheral surface of the inner ring plate (15b) (16b) and an external connection conductor (21) forming the inner wall of the cylinder.
) (22) so that the pressing force acts evenly on the side surface.

The water flow holes (34) (35) are connected to the cooling water flow holes (36) through the insulating bulkhead (18) to the import (Pl) and out port (P2) formed in each outer ring plate (15a) (16a). ) (37).

A pair of positive and negative terminal boards (15) (1
6) has six common bolt holes (38...) and two
Two positioning pin insertion holes (39...) are drilled in the outer ring plate in the circumferential direction of the conductive shaft (12) each time, and a common bolt hole (38...) is bored in the outer ring plate in the circumferential direction of the conductive shaft (12).・・・
) and the pole inserted into the insertion hole (39...) (4
The power supply unit (10) of the present device is removably attached using the power supply unit (10) and the positioning pin (41).

The present invention will be explained in detail using the above configuration.

The spot welding gun (12) moves as instructed by the movements of the robot's operating arm and the B-axis indirect power supply unit (10), and performs the predetermined work.

Then, during welding, the gun arms (5) (6) are rotated by the pressure cylinder (7), and the electrode tip (8)
(9) pressurizes the workpiece to be welded, and each pressure ring (33) (3
3) passes welding current while pressing each contactor (31) (32), the welding current is connected from one terminal (25) of the secondary cable (24) connected to the welding transformer. The current flows through the conductor (21) and the contactor (
31) to the inner ring plate (15b) and conductive shaft (12)
From there, it flows through the flexible connecting conductor (13), through the gun arm (5) and between the electrodes (8) and (9). The current flowing through the welding gun flows from the flexible connecting conductor (13) to the outer ring plate (16a) and then to the inner ring plate (16b), passes through the contactor (32), flows to the flexible connecting conductor (22), and flows to 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, and the inner ring plate (15b) and (1
6b) is the horizontal surface of the contactor (31) (32) and thrust washer (19) (1a), and the outer ring plate (15)
a) and (16a) slide on the vertical surface of the thrust washer, respectively.

In this embodiment, a case has been described in which the power supply unit of the present invention is used in the joint of the B-axis, 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 of the B-axis, the T-axis, etc.
Needless to say, it can be used for the above joints.

<Effects of the Invention> As described above, according to the present invention, a set of ring-shaped positive and negative contactors is installed in a cylinder chamber formed between each set of positive and negative terminal plates and an external connection conductor. The pressure of the air supplied indoors connects a pair of connecting conductors and their corresponding terminal plates with each contactor to form a reciprocating path for the welding current. Rather than moving between them and making them contact two-dimensionally,
Since local contact can be made 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, further extending the life of the indirect power supply unit. Moreover, it is lightweight and compact, and instead of using expensive materials such as flexible copper plates for the external connection conductors that connect the receiving and feeding plates as in the past, it is possible to weld inexpensive external connection conductors such as rigid materials. It can be installed independently of gun movement.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the entire 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 B-B of Figure 2.
Arrow view. Explanation of symbols> 4... Installation on the welding gun side vi12... Conductive shaft 14... Mounting plate on the drive side 15.16... One set of positive and negative terminal plates 21.22
... External connection conductor 30 ... Cylinder chamber 31.32 ... Positive jL pair of contactors 33.
33' ... Pressure ring Fig. 1 t Fig. 2 K: Mounting plate I2zml on the side of the shy side

Claims (1)

[Claims] 1. Between the mounting plate on the drive side and the mounting plate on the welding gun side,
A conductive shaft is fixed in position, and a pair of positive and negative terminal plates are installed on the conductive shaft, which penetrate the inner diameter of a pair of positive and negative external connection conductors and can move together with the conductive shaft. An annular cylinder chamber facing in the circumferential direction of the terminal plate is formed between the terminal plate and the external connection conductor, and this cylinder chamber includes a pair of cylinders that can be moved outwardly relative to each other by fluid pressure. With the pressure ring and the pressing force of this pressure ring,
A joint power supply unit for a resistance welding machine, in which a pair of positive and negative external connection conductors and a ring-shaped pair of positive and negative contactors are installed to movably electrically connect terminal plates. 2. In the joint power supply unit according to claim 1, the cylinder chamber is connected to a pressurizing cylinder of a welding gun only during welding pressurization to apply a pressing force to the pressurizing ring of the resistance welding machine. Joint power supply unit.