JPS62173089A - Tip dresser for welding machine - Google Patents

Abstract

PURPOSE:To perform the dressing of a tip electrode with good accuracy automatically by providing a rotary file at the tip part of the arm which is provided rockably on the welding machine main body and by bringing the rotary file into contact with the tip electrode by inverting it in its axial direction. CONSTITUTION:The projection nut is pressed and electrified with the descent of the upper tip 1000 by a pressing device 900 and welded to the work, when the work is placed on the lower tip 800 and the projection nut is placed on a positioning pin 701. On completion of this welding stage the upper tip 1000 is ascended and the positioning pin 701 is descended as well and the work is removed from the lower tip 800. While the upper tip 1000 is ascending an arm 101 is located between the upper and lower tip 1000, 800 with its rocking and when the rotary file 102 at the tip part thereof is opposed to the surface of the lower tip 800, the upper face of the rotary file 102 is pressed with the descent of the upper tip 1000 and the rotary file 102 performs the dressing of the surface of the lower tip 800.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a tip dresser for shaping and polishing opposing surfaces of a pair of tip electrodes of a resistance welding machine.

<Conventional technology> In resistance welding such as spot welding and projection welding, a workpiece to be welded is sandwiched between a pair of tip electrodes (hereinafter sometimes simply referred to as tips), and a current is passed between the electrodes. Welding is performed using Joule heat, which is generated frequently. Repeated welding can cause welding particles to adhere to the tip electrode surface or cause local wear, so in order to maintain welding quality, the tip electrode surface must be shaped, polished, or dressed to always maintain a good surface. must be maintained. Particularly in the recent projection nut welding to synchro metal, the tip electrode on the lower side is severely worn, and changes in electrical resistance due to adhesion of welding debris called spatter also adversely affect welding quality.

In the conventional dressing of a tip electrode, for example, in the case of a tip electrode with a flat opposing surface, an operator would dress the tip electrode using an appropriate spatula or pear while checking the welding quality.

<Problems to be Solved by the Invention> However, such manual dressing is not only time-consuming but also has the problem of making it difficult to achieve sufficient parallel surface accuracy.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tip dresser for a welding machine that can automatically dress a tip electrode with high precision.

<Means for Solving the Problems> The tip dresser according to the present invention includes an arm swingably provided on the welding machine main body, a rotating file provided at the tip of this arm, and the arm and rotating file respectively. and means for driving the rotary file in its axial direction to bring it into contact with the tip electrode surface.

<Operation> While the pair of tip electrodes are separated, the arm swings and the rotating shaft faces the tip electrode surface, and then comes into contact to dress the tip electrode surface.

<Example> FIG. 1 shows an example of a glossection nut welding machine equipped with a tip dresser according to the present invention.

The tip dresser 100 is supported by a cylindrical support arm 300 on the side surface of the welding machine main body 200.

A platen 400 is mounted on a bed 500 in front of the welding machine main body 200, and a positioning bin shift device 700 for a projection nut is mounted on the platen 400 via a split jig 600. . A lower chip 80 is provided at the upper end of the positioning bin shift device 700.
0 is held, and on the opposite side, at the lower end of the pressurizing device 900, there is an upper chip 100 that moves up and down by the pressurizing device 900.
0 is set.

The workpiece held by the operator or robot is placed on the lower tip 80.
0, a projection nut is supplied from an automatic feeding device (not shown), and its screw hole is inserted into the positioning pin 701 on the lower chip 800. Subsequently, the upper tip 1000 is lowered from above, and the projection nut is pressurized and energized to weld. When this welding process is completed, the upper tip 1000 is raised and the positioning bin 701 is lowered, and the workpiece is removed from the lower tip 800 and transported to a predetermined location. While the chip 1000 is being raised, the arm 1 of the chip dresser 100
01 swings and is positioned between the upper and lower tips 1000 and 800, and the rotary file 102 at its tip is the lower tip 800.
When facing the surface of the upper chip 1000, the upper chip 1000 descends and presses the upper surface of the rotating shaft 102, and the rotating shaft 102 dresses the surface of the lower chip 800. This dressing may be performed every time a workpiece is removed from the lower tip 800 and the next workpiece is set on the lower tip 800, or once every few times depending on the wear of the tip etc. You may do so. In addition, during welding, the pressure device 900 is applied to the upper tip 1000 at a pressure of 200 to 800' p/c! However, during dressing, an appropriate load can be applied to a low-pressure air circuit provided separately from the pressurized air circuit for welding. As will be described later, a floating disk is provided on the upper part of the rotating shaft 102, so that the part that the upper chip 1000 contacts does not rotate.
Only the rotating shaft 102 below it rotates.

Next, referring to Figures 2 and 3, Chipdo ζ
- Details of Lesser 100 will be explained. The tip dresser 100 is attached to the side surface of the welding machine main body 200 via a support arm 300 having a circular cross section.

An end plate 103 is welded to the elliptical end surface of the support arm 300 on the chip dresser 100 side, and a mounting board 104 is bolted to the end plate 103. An air cylinder mounting bracket 106 is attached to one side of the mounting board 104 via a main bracket 105, and an air cylinder 107 is held on this bracket. The piston rond end in the air cylinder 107 is screwed to a two-pronged joint 108 of a knuckle joint, and together with a connecting piece 109 constitutes a knuckle joint so that the arm 101 can swing.

The main bracket 105 is L-shaped and has arm mounting platens (111, 112) and the air motor 1 on the side opposite to the air cylinder mounting bracket 106.
Brackets 114 for attaching (13) are each bolted. Arm mounting bracket 111
, 112 are each fitted with a shaft 117 through ball bearings 115 and 116, and the lower end of the shaft 117 is connected to a drive shaft 113a of an air motor 113 through a joint 118.

Arm 101, base end side members 101a, 101
b, and members 101c and 101d on the distal end side, each of which is bolted to each other. Member 1011L on the proximal end side.

101b forms two prongs in the vertical direction and is rotatably attached to the shaft 117 via ball bearings 119 and 120, respectively. At the forked part of the arm 101,
A sprocket 121 is fixed, and a chain 122 is hooked between the rotary shaft 102 at the tip of the arm 101. In order to adjust the tension of the chain 122, the distal end member 101c of the arm 101 is attached to the proximal end member 101b so that its position can be adjusted over its length.

The distal end of the arm 101 also includes distal side members 101c, 101.
d constitutes two forked parts in the vertical direction, and as shown in FIG. 4, a sprocket holder 126 to which a sprocket 125 is fixed is attached to each of them via ball bearings 123 and 124. . A spline groove is formed in the center of the sprocket holder 126, and a spline shaft 127 is fitted in this groove so as to be movable in the axial direction. A through hole is formed in the center of the spline shaft 127, and a shaft screw 129 is inserted into this hole from above through a spring seat 128. At the bottom of the hole, a disk-shaped screw 130 is provided with a square hole to prevent rotation. It is then fixed with screws. That is, the shaft screw 129
Spring seat 128, spliner 7
) 127, the file 130 is integrated and is movable only in the axial direction within the sprocket holder 126. A compression coil spring 131 is inserted into the space between the spring seat 128 and the sprocket holder 126 to constantly press and bias the spring seat 128 upward. It's hitting. and spring seat 1
A floating disk 133 is disposed on the upper surface of 28 via a thrust needle roller bearing 132, and the floating disk 133 is held down by a cover 134.

Therefore, when the floating disc 133 is pressed from above by the upper chip 1000, the spring seat 128 presses the spring 131 and at the same time pushes the shaft 130 downward, so that the contact surface of the upper and lower chips and the shaft surface The parallelism will be obtained.

The arm 101 is connected to the air cylinder 1 as shown in FIG.
The working position P1 is pushed out by 07, and the retracted position P2 is pulled out. Working position P1 is main block 1
When the arm 101 is located at the working position P1, the rotation of the tip thereof is regulated by a stopper 137 attached to a stopper support member 135 fixed to the stopper support member 135 via an adjustment screw 136. The center of
The adjusting screw 138 is finely adjusted to match the center of the upper and lower tips of the welding machine body.

Next, referring to FIG. 5, the positioning pin shaft device 700
I will explain about it. The positioning pin 701 is used to position both the workpiece and the glojection nut, and is electrically insulated. The positioning pin 701 consists of a lower 7 flange portion 701a, an intermediate body portion 701b, and an upper head portion 701c.
1b is movably accommodated in a through hole provided in the center of the lower chip 800, and is prevented from being removed upwardly by the flange portion 701a. This 7 lunge part 701
a is not necessarily necessary if upward positioning is possible by the stroke end of the air cylinder, which will be described later.

A pin 702 is press-fitted into the lower part of the positioning pin 701, and this pin 702 and the K shaft 703 are connected to the set screw 7.
It is fixed to 04. Pin 702 may be formed integrally with pin 701. The lower end of the shaft 703 is 7
Air cylinder 7 via 0-ting joint 705
It is screwed or fixed to the piston rod 707 of 06.

The lower tapered portion 800a of the lower chip 800 is fitted into the tapered hole 708a of the adapter 708, and
The lower threaded portion 708b of 8 is a straight holder 709.
is screwed into the screw hole 709a. Lower tip 80
0 may be directly attached to the straight holder 708. This straight holder 709 is attached to the platen 400.
It is attached to a split mold jig 600 fixed above. A square block 7 is placed at the bottom of the straight holder 709.
10 is welded, a square support 711 is bolted to this square block 710, and an air cylinder 706 is supported by this support 711. And the shaft 703 is
Bush 71 on straight holder 709 and column 711
2, 713, and is supported by an air cylinder 706 so as to be able to slide up and down.

A limit switch is disposed at the bottom of the air cylinder 706 to detect the upper and lower ends of the stroke of the air cylinder 706, and when the stroke is at the upper end, the positioning pin 701 protrudes from the upper surface of the lower tip 800 as shown in the figure. At the lower end, the positioning pin 701 is completely buried in the upper surface of the lower chip 800.

Each of the above-mentioned units is controlled by a control unit (not shown). That is, in FIG. 1, when a workpiece is placed on the lower chip 800 and a projection nut is placed on the positioning pin 701, the upper chip 1000 is lowered by the pressure device 900, pressurizing the projection nut and placing it on the workpiece. Weld. This welding is performed almost instantaneously, and when the upper tip 1000 rises, the positioning pin 701 descends, making it easier to take out the work and transport the work. Next, the rotating shaft 102 rotates and the arm 101 swings, and when the rotating shaft 9102 faces the surface of the lower chip 800 in which the positioning pin 701 is buried,
The upper tip 1000 descends again to apply pressure to the rotary file 102, and the surface of the lower tip 8oo is dressed for a certain period of time according to a timer. Subsequently, the upper tip 1000 rises and rotates, and the arm 101 stops rotating.
is retracted to its original position, and the positioning pin 701 rises again to protrude from the surface of the lower chip 800 and maintains its position.

In the above configuration, dressing of other chips is also possible by matching the shape of the polished surface of the rotating shaft to the shape of another chip, for example, the shape of a spot welding chip. In addition, if the tip is rotated or installed with the pear facing upward, it is possible to dress the upper tip. Furthermore, the arm itself provided with the rotating file 9 may be moved up and down to bring the rotating file into contact with the chip. Further, the welding machine may be of a type that performs welding on a platen.

It goes without saying that this invention can be modified in various other ways.

<Effects of the Invention> As described above, the tip dresser for a welding machine according to the invention includes an arm provided to be able to swing the welding machine main body, a rotating file provided at the tip of this arm, an arm and a tip dresser for a welding machine. Since it is provided with means for driving each rotary file and means for moving the rotary file in its axial direction to contact the tip electrode surface, it is possible to dress the chip accurately and safely in a short time. Particularly when this invention is used in a system that automatically performs everything from supplying workpieces to unloading them with a robot, chip dressing can be done during the waiting time between welding, greatly improving work efficiency. improves.

[Brief explanation of drawings]

FIG. 1 is an external perspective view of a welding machine equipped with a tip dresser according to the present invention, FIG. 2 is a partially sectional side view of the tip dresser shown in FIG. 1, and FIG. 3 is a plan view of the tip dresser. 4 is an enlarged view of section A in FIG. 2, and FIG. 5 is a cross-sectional side view of the positioning pin shift device shown in FIG. 1. 100...Chip dresser, 1o1...Arm,
1o2...Rotating gear, i), 107...Air cylinder, 113...Air motor, 200...Welding machine body, 3oo...Support arm, 400...Platen, 500...Bed, 6oo...split type jig, 70
0... Positioning pin shift device: 701... Positioning pin, 800... Lower chip, 9oo... Pressure device, 1000... Upper chip.

Claims (1)

[Scope of Claims] An arm that is swingably provided on a welding machine main body and can enter between a pair of tip electrodes; a rotating file that is rotatably provided on the arm at a position corresponding to the tip electrode; means for swinging the arm to make the rotary file face the tip electrode; means for following the rotary file in its axial direction to bring it into contact with the tip electrode; and rotating the rotary file to bring the rotary file into contact with the tip electrode. Welding machine tip dresser with means for polishing.