JP3261788B2 - Current collector of welding torch for robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current collector for an arc welding welding torch used for a welding robot or the like.

[0002]

2. Description of the Related Art Conventionally, when rotating a welding torch attached to an arm or a tip of a wrist of a welding robot, the welding torch is rotated in order to supply current to a core wire passing through the welding torch while rotating the welding torch. A current collector is provided at the base of the torch. For example, as shown in FIG. 3, the structure is such that a slip ring 3 having a cylindrical outer circumference is supported by a drive motor so as to be rotated by a drive motor, and a brush holder 6 provided on the outer circumference side of the slip ring 3 is provided. The sliding carbon brush 7 is pressed radially toward the slip ring 3 by a spring 8 ′. The spring 8 ′ is formed by spirally winding a strip-shaped spring steel plate to press the head of the carbon brush 7. At the center of the slip ring 3, a feed hole 31 for passing the core wire 4 is provided so that current is always supplied from the slip ring 3. As another conventional example, as shown in FIG. 4, the slip ring 3 is formed in a disk shape, the carbon brush 7 is also formed in a donut shape, and a plurality of springs 8 arranged at equal intervals in the circumferential direction. In some cases, the carbon brush 7 is axially pressed toward the slip ring 3 via the brush holder 6.

[0003]

However, in the former configuration, since the spring is formed in a spiral shape, the spring further projects radially from the head of the carbon brush, and the brush holder also holds the spring. When the welding torch is moved by a welding robot, the current collector installed at the base of the welding torch hits a workpiece or jig, and the welding robot moves. However, there is a problem that the operation range is restricted and maintenance and inspection are troublesome. In the latter configuration, the donut-shaped carbon brush is pressed in the axial direction to make it compact, but because the shape is a donut shape, the pressing pressure tends to be uneven, and the carbon brush and the slip ring Contact becomes unstable,
When an electric current is applied, the contact surface of the slip ring becomes partially defective, and a local overheating phenomenon may occur.
The present invention has been made to solve such a problem, and an object of the present invention is to provide a current collector of a welding torch for a robot, which can obtain a compact and stable contact state.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to a sprocket hole which is driven by a driving motor disposed in a casing attached to a wrist of a robot, and through which a core wire passes through the center. A rotatable slip ring having: a carbon brush that is slidably housed in a sliding hole of a brush holder disposed in the casing, and that supplies a current from a welding power source in contact with the slip ring; A current collector for a robot welding torch having a spring for pressing a carbon brush against the slip ring, wherein the slip ring is formed in a cylindrical shape and is positioned below the drive motor; A plurality of sliding holes are provided radially while being attached to the fixed portion on the outer peripheral side of the ring. Is formed by a ring spring formed in a continuous ring shape, and the head of each of the carbon brushes inserted into the sliding hole is always slip ringed through a spring receiver provided with a concave portion with which the ring spring engages. In the direction of.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. FIG. 1 is a side sectional view showing an embodiment of the present invention, and FIG. 2 is a plan sectional view. As shown in FIGS. 1 and 2, a drive motor 24 and a hollow shaft 22 are arranged in parallel inside a casing 2 fixed to the wrist 1 of the welding robot, and the hollow shaft 22 is attached to the casing 2. Bearing 21
Support through. A gear 23 is concentrically fixed to the hollow shaft 22, and is rotated by a drive motor 24 via a gear 25. The gear 23 has a core 4
And a slip ring 3 made of a cylindrical conductor are fixed concentrically. The slip ring 3 is located below the drive motor 24. At the center of the slip ring 3, there is provided a feed hole 31 through which the core wire 4 passes. As shown in FIG. 2, a brush holder 6 having a plurality of sliding holes 61 is provided radially on the outer peripheral side of the slip ring 3, and is fixed to the casing 2. A carbon brush 7 is inserted into each of the sliding holes 61, and the head of the carbon brush 7 is pressed by a ring spring 8, which is a ring-shaped coil spring and can be contracted in a radial direction, via a spring receiver 71 made of an insulating material. The carbon brush 7 is always pressed against the slip ring 3. Note that a concave portion with which the ring spring 8 is engaged is provided on the upper surface of the spring receiver 71. The slip ring 3, the carbon brush 7, the spring receiver 71, and the ring spring 8 constitute a slip ring mechanism. According to the present invention, since the slip ring mechanism is located below the drive motor 24, the slip ring mechanism does not interfere with the drive motor 24 at all. Therefore, the drive motor 24 and the slip ring mechanism can be brought close to each other, and the device can be made compact. In addition, since the slip ring mechanism does not interfere with the drive motor 24, the slip ring mechanism can be easily disassembled and assembled, and maintenance and inspection can be performed easily. Further, the spring is constituted by a ring spring 8 in which a coil spring is formed in a continuous ring shape, and the head of each carbon brush 7 inserted in the sliding hole 61 is
Spring receiver 71 provided with a concave portion with which the ring spring 8 engages
, The ring spring 8 can effectively function at any position in the circumferential direction, and can move in the axial direction by the recess. Therefore, the plurality of carbon brushes 7 can always be reliably pressed against the slip ring 3 with a uniform pressure. Further, since the head of the carbon brush 7 is pressed by the ring spring 8, the ring spring 8 does not protrude largely in the radial direction from the head of the carbon brush 7, and the brush holder 6 is smaller than the outer periphery of the ring spring 8. In addition, the current collector can be made compact. Also, since the carbon brush 7 divided into a plurality is pressed in the radial direction of the slip ring 3 by one ring spring 8, the number of parts is small, the structure for pressing the carbon brush 7 is extremely simple, and maintenance and inspection are performed. And each carbon brush 7 is not affected by the contact state of the other carbon brushes 7 and the optimum contact state can always be maintained.

[0006]

As described above, according to the present invention, the following effects can be obtained. (1) Since the slip ring mechanism is located below the drive motor 24, the slip ring mechanism does not interfere with the drive motor 24 at all. Therefore, the drive motor 24 and the slip ring mechanism can be brought close to each other, and the apparatus can be made compact. This allows
Even when welding a workpiece having a complicated shape, the operating range of the welding robot is not restricted. (2) Since the slip ring mechanism does not interfere with the drive motor 24, the slip ring mechanism is disassembled. Assembly is easy, and maintenance and inspection can be performed easily. (3) The spring is constituted by a ring spring 8 formed by forming a coil spring into a continuous ring shape, and the head of each of the carbon brushes 7 inserted into the sliding hole 61 is formed by a concave portion with which the ring spring 8 is engaged. The spring is always pressed in the direction of the slip ring 3 through the spring receiver 71 provided with the ring spring 8, so that the ring spring 8 can function effectively at any position in the circumferential direction, and moreover, in the axial direction. Since it does not move due to the recess, the plurality of carbon brushes 7 can be constantly and reliably pressed against the slip ring 3 with a uniform pressure. (4) Since the head of the carbon brush 7 is pressed by the ring spring 8, the ring spring 8 does not protrude significantly from the head of the carbon brush 7 in the radial direction.
Since the brush holder 6 is also smaller than the outer circumference of the ring spring 8,
The current collector can be made compact. (5) Since the carbon brush 7 divided into a plurality is pressed in the radial direction of the slip ring 3 by one ring spring 8, the number of parts is small, the structure for pressing the carbon brush 7 becomes extremely simple, and maintenance is performed. Inspection is easy and each carbon brush 7
Is not affected by the contact state of the other carbon brushes 7,
An optimal contact state can always be maintained.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a plan sectional view taken along the line AA of FIG. 1;

FIG. 3 is a plan sectional view showing a conventional example.

FIG. 4 is a side sectional view showing a conventional example.

[Explanation of symbols]

 Reference Signs List 3 slip ring 31 feed hole 4 core wire 5 torch part 6 brush holder 61 sliding hole 7 carbon brush 71 spring receiver 8 ring spring

Claims (1)

(57) [Claims] 1. A rotatable slip ring, which is rotatably driven by a drive motor disposed in a casing attached to a wrist of a robot and has a feed hole through a center wire, and is disposed in the casing. Robot welding comprising a carbon brush slidably housed in a sliding hole of a brush holder and supplying current from a welding power source in contact with the slip ring, and a spring pressing the carbon brush against the slip ring. In the torch current collector, the slip ring is formed in a cylindrical shape and positioned below the drive motor, and the brush holder is attached to a fixed portion on an outer peripheral side of the slip ring, and a plurality of slides are radially formed. A hole is provided, and the spring is constituted by a ring spring in which a coil spring is formed in a continuous ring shape. A welding head for the robot, wherein the head of each of the carbon brushes inserted into the sliding hole is always pressed in the direction of the slip ring via a spring receiver provided with a concave portion with which the ring spring engages. Torch current collector.