JP2001259855A - Method of positioning electrode tips and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly and surely perform the positioning work of a pair of electrodes composing a motor-driven welding gun, to decrease the electric power needed for the positioning of the electrode tips, and to save the working cost. SOLUTION: An electric power generator 100, which is composed as a separated body from a motor-driven welding gun 10, is connected to a first power supply outlet 92 via a power cable 118 after at least one of or both of a movable electrode tip 38 and a fixed electrode tip 44 are replaced. An electric power is manually generated with the electric power generator 100 and a servo motor 30 is driven by the power. The movable electrode tip 38 is moved and brought close to the fixed electrode tip 44 under the operation of the servo motor 30, and the positioning of the movable electrode tip 38 and the fixed electrode tip 44 is performed by observing the approaching state visually.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for aligning a set of electrode tips constituting an electric welding gun.

[0002]

2. Description of the Related Art For example, an electric welding gun has a servomotor, a set of electrode tips, and a feed screw mechanism which can move one of the set of electrode tips. The servo motor is connected to a work welding power supply (AC power supply), and the feed screw mechanism operates under the action of the servo motor. When welding a work using the electric welding gun, the work is sandwiched between the electrode tips, and the work is welded by applying a current between the electrode tips while applying pressure by a feed screw mechanism. Reach. By the way, if welding to a work is repeatedly performed, the electrode tip will be worn, and it is necessary to dress or replace the electrode tip. Further, even when the electrode tip is damaged due to a human error, the electrode tip needs to be replaced.

[0003] One of the electrode tips,
Alternatively, after both have been replaced, the electrode tips must be aligned with each other. This is because, when the work is welded without performing the alignment of the electrode tip, the electrode tip is displaced from a predetermined hitting position of the work, which causes a welding defect.

[0004] One example of a method for aligning the electrode tips is to replace one of the electrode tips and then move one of the electrode tips to the other electrode tip via a feed screw mechanism under the action of a servomotor after replacing the electrode tip. Then, the electrode tips are visually positioned.

[0005]

However, in the above-described electrode tip positioning method, a servomotor constituting a feed screw mechanism is driven by a work output power supply (AC power supply) having a large output. Not only is the moving speed too fast, but it is difficult to finely adjust the position with respect to the electrode tip. Further, the work welding power supply requires a large amount of power due to high output, and causes an increase in work cost.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and after replacing an electrode tip constituting an electric welding gun, it is possible to surely perform the positioning of the electrode tip. An object of the present invention is to provide a method and an apparatus for positioning an electrode chip, which can reduce the power required for the positioning of the chip and reduce the operating cost.

[0007]

According to the present invention, there is provided a method for aligning a set of electrode tips constituting an electric welding gun, wherein a generator is connected to a power supply connection port of the electric welding gun via a power line. Then, by supplying the electric power generated by the generator to the electric motor of the electric welding gun and rotating the electric motor, one of the electrode tips of the set of electrode tips is replaced with the other of the electrode tips. And the electrode tip is aligned.

According to the invention, the power generated by the power generator is extremely smaller than the power supplied from the welding power source used for welding the work, so that the moving speed of the electrode tip can be increased. Can be slowed down. Thereby, the approaching state of the other electrode tip with respect to the one electrode tip can be visually confirmed with certainty, so that the mutual positioning of the electrode tips can be performed accurately.

In the above-described electrode tip positioning method, it is preferable that power is supplied to the motor by manually rotating the generator to move one electrode tip relative to the other electrode tip. Thus, the generator can be rotated at a desired rotation speed, so that the electric power generated from the generator can be easily adjusted.
Since the moving speed of the electrode tip corresponds to the power generated from the generator, the moving speed of the electrode tip can be easily adjusted.

Further, the present invention provides a positioning device for a set of electrode tips constituting an electric welding gun, wherein the electric motor, a displacement mechanism driven by the electric motor, and a detachably attached to the displacement mechanism. A movable electrode tip, a fixed electrode tip facing the movable electrode tip, and a generator, and supplying another electric power to the electric motor from the electric power source for welding from the generator to the electric motor. By rotating, one of the pair of electrode tips is moved closer to the other electrode tip, and the electrode tips are aligned.

As a result, an extremely small amount of electric power can be supplied to the electric motor as compared with a welding power source used for welding the work, so that the electric power required for the alignment of the electrode tips can be reduced. It is easy to adjust the relative moving speed of the electrode chips, and it is also possible to visually check the proximity of the electrode tips and the alignment thereof, thereby achieving a quick alignment operation and a low operating cost.

In the electrode tip positioning apparatus having the above-described configuration, a connection terminal for supplying power to the motor during welding and a connection terminal for supplying power for positioning from the generator are provided. It is preferred that they be shared. This is because the power source for welding and the power source for positioning are supplied from the same connection terminal, so that the number of components provided in the electric welding gun main body can be reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the method for positioning an electrode tip according to the present invention in relation to an apparatus for performing the method will be described below with reference to FIGS. Will be described. In addition. This embodiment is applied to, for example, an electric welding gun in which one electrode tip of a set of electrode tips is moved and approached to the other electrode tip via a feed screw mechanism under the action of a servomotor. (Hereinafter simply referred to as an electric welding gun according to the embodiment).

An electric welding gun 10 according to the present embodiment.
Is attached to the distal end of a robot arm 12 of a robot that welds the work W, as shown in FIG. The electric welding gun 10 has a gun support 14 and a gun body 16. The gun support 14 is attached to the tip of the robot arm 12 and fixedly supports the gun body 16.

The gun support section 14 has a gun support bracket 18, and the gun support bracket 18 is
8a and lower plate 1 extending in parallel with upper plate 18a
8b. The upper plate 18a and the lower plate 1
8b, a guide bar 20 is bridged.

The guide bar 20 includes the guide bar 2
A plate 22 which is slidable in the axial direction 0 and parallel to the upper surface plate 18a and the lower surface plate 18b is fitted. On the upper part of the plate body 22 on the side close to the robot arm 12, a case-like support 24 is disposed, and
A first coil spring 26 wound around the guide bar 20 is interposed between the support 8a and the support 8a. Similarly, a second coil spring 28 wound around the guide bar 20 is interposed between the lower plate 18 b and the plate 22.

A servo motor 30 constituting the gun body 16 is fixedly held on an upper portion of the plate 22 on a side separated from the robot arm 12. This servo motor 3
A rod 32 engaged with the zero rotor 50 extends downward through the plate body 22 and the lower plate 18b. The structure of the servo motor 30 will be described later in detail.

The rod 32 is surrounded by a gun body 34 fixed to a lower portion of the lower surface plate 18b. A movable electrode tip 38 is detachably attached to a tip of the rod 32 via a holder 36. Is held. The movable electrode tip 38 is pressed into a hole 37 formed in the holder 36 (see FIG. 2).

Further, on both sides of the plate body 22, a pair of C-shaped yokes 40a and 40b extend downward, and a holding member 42 bridged between the yokes 40a and 40b.
Holds the fixed electrode tip 44. The fixed electrode tip 44 is press-fitted and held in the holding member 42 in a detachable manner, similarly to the movable electrode tip 38. Of course,
The fixed electrode tip 44 is arranged to face upward so as to face the movable electrode tip 38. In addition,
For convenience of description, FIG. 1 shows only one yoke 40a.

Servo motor 30 constituting gun body 16
As shown in FIG. 2, a motor housing 46, a plurality of electromagnets 48 arranged annularly inside a lower portion of the motor housing 46, and an annular permanent magnet 52 facing the electromagnets 48 are fixed, and The housing 50 includes a rotor 50 having a hollow portion 54 and a housing cover 56. The housing cover 56 is screwed to an upper end of the motor housing 46.

An opening 60 is formed at the upper end of the rotor 50 as a recess. A thin plate 62 made of a lightweight and highly rigid aluminum alloy is attached to the upper surface of the rotor 50 to close the opening 60.

First and second bearings 64 and 66 are externally fitted on the upper outer side of the rotor 50, and a third bearing 68 is externally fitted on the lower outer side. A tightening nut 70 is screwed onto the rotor 50 at an upper portion of the first bearing 64, and pressurizes the first bearing 64 with the tightening nut 70 to cause a play in the axial direction of the rotor 50. Prevents sticking.

The rod 32 having a space therein is inserted into the hollow portion 54 of the rotor 50, and a nut member 72 is fixed to one end of the rod 32. Therefore, a chamber 74 is formed inside the rod 32.

A feed screw 76 screwed with the nut member 72 is inserted into the chamber 74 of the rod 32, and one end of the feed screw 76 has an opening 6 at the upper end of the rotor 50.
It is engaged in the projection 0. Therefore, the nut member 7
2 and the feed screw 76, a feed screw mechanism 7 for converting the rotation of the rotor 50 into a vertical movement of the rod 32.
8.

A head cover 80 is mounted above the housing cover 56 of the servomotor 30 (see FIG. 2). An encoder 82 for detecting the rotation angle of the rotor 50 is arranged in the head cover 80. The encoder 82 includes an encoder body 84 and an input shaft 86 protruding downward from the encoder body 84. The encoder body 84 is held by a cylindrical stay 88 fixed to the housing cover 56. The input shaft 86 is connected to the thin plate 62 through a hole 90 provided substantially at the center of the housing cover 56.

As shown in FIGS. 1 and 2, power lines 93 and 95 from a work welding power source 91 serving as a driving source for operating the servo motor 30 and the encoder 82 are connected to the side surface of the head cover 80. Are provided with substantially L-shaped first and second power supply connection ports 92 and 94. The connection terminals 92a and 94a of the first and second power supply connection ports 92 and 94 are directed downward.

In the motor housing 46 and the head cover 80, a servo motor power line 96 connecting the first power supply connection port 92 and the plurality of electromagnets 48 is routed through the housing cover 56. I have. Similarly, an encoder power line connecting the second power supply connection port 94 and the encoder body 84 is wired in the head cover 80.

The present invention further relates to the electric welding gun 1 described above.
0 includes a generator 100 and the like separately configured. As shown in FIG. 3, the generator 100 includes a main body 102 and a shaft 10 having a keyway 106 formed thereon.
4, a key 110 provided on the handle 108 is fitted into the key groove 106, and a threaded shaft 112 penetrating through the handle 108 is screwed to the axis of the shaft 104, and the handle 108 is The structure is fixed to the shaft 104. On one side surface of the main body 102, two substantially L-shaped connection ports 114 and 116 for connecting a power line are provided, and connection terminals 114a and 116a of the connection ports 114 and 116 are horizontally oriented. I have. The generator 100
Is to manually obtain a predetermined power supply by rotating the handle 108, and its internal structure is the same as that of a conventional generator, so that detailed description thereof will be omitted.

The electric welding gun 10 according to the present embodiment.
Is basically constructed as described above. Next, the movable electrode tip 3
Electrode tip 38 and fixed electrode tip 4 after replacing at least one of 8 and fixed electrode tip 44
4 will be described.

First, for example, one or both of the movable electrode tip 38 and the fixed electrode tip 44 which need to be replaced due to wear or the like are removed from the holder 36 and the holding member 42, respectively, and replaced with new ones. The holder 36 is pressed into the holding member 42.

Then, power lines 93 and 95 from a work welding power supply 91 serving as a drive source for operating the servo motor 30 and the encoder 82 are connected to the first and second power supply connection ports 9.
2 and 94 from the respective connection terminals 92a and 94a, the work welding power supply 91 and the electric welding gun 1
0 is electrically cut off.

Thereafter, as shown in FIG. 4, a connection port 11 provided in a generator 100 separate from the electric welding gun 10 is provided.
One end of the power line 118 is connected to the fourth connection terminal 114a, and the other end of the power line 118 is connected to the connection terminal 92a of the first power supply connection port 92 provided in the electric welding gun 10. When the weight of the generator 100 is heavy, the transfer may be performed by a cart, for example.

The electric welding gun 10 and the generator 10
After the connection with the steering wheel 1 of the generator 100 is completed,
08 is manually rotated. Thereby, the generator 10
Electric power is generated by the action of a permanent magnet (not shown) built in the main body 102 of the digital camera. This power is supplied to the power line 11
The motor 8 is supplied to a servo motor 30 which constitutes the electric welding gun 10 through 8, and the servo motor 30 is driven.

At this time, the electric power is supplied to the plurality of electromagnets 48 via the power line 96 for the servomotor wired in the motor housing 46 and the head cover 80, and the electromagnets 48 and the annular A magnetic field is generated under the action of the permanent magnet 52, and the magnetic field causes the rotor 50 of the servo motor 30 to rotate. The feed screw 76 constituting the feed screw mechanism 78 rotates under the rotation of the rotor 50, and the nut member 72 screwed to the feed screw 76 moves in the axial direction of the feed screw 76. When the nut member 72 rotates the feed screw 76, the rod 32 fixed to the nut member 72
2, the feed screw 76 moves down in the axial direction. Therefore, the holder 36 fixed to the tip of the rod 32
Is moved downward in the axial direction of the servo motor 30 in a direction approaching the fixed electrode tip 44.

In this case, the moving speed of the movable electrode tip 38 corresponds to the rotation speed of the shaft 104 (the rotation speed of the handle 108), that is, the amount of electric power generated by the generator 100. Therefore, the moving speed of the movable electrode tip 38 with respect to the fixed electrode tip 44 can be easily adjusted by adjusting the rotation speed of the handle 108. Specifically, while visually observing the state in which the movable electrode tip 38 approaches the fixed electrode tip 44, the number of rotations of the handle 108 is adjusted to adjust the movable electrode tip 3.
8 and the fixed electrode tip 44 are aligned.

After the positioning of the movable electrode tip 38 and the fixed electrode tip 44 is completed, the power line 11
8 is separated from the connection terminal 92a to electrically cut off the electric welding gun 10 and the generator 100. Thereafter, the power lines 93 and 95 from the work welding power supply 91 are connected to the connection terminals 92a and 94a of the first and second power supply connection ports 92 and 94, respectively, and the apparatus is put on standby for normal welding work.

In this embodiment, after at least one or both of the movable electrode tip 38 and the fixed electrode tip 44 are replaced, the positioning of the movable electrode tip 38 and the movable electrode tip 44 is performed. In this case, the power source for the servo motor 30 is not the power source 91 for work welding, but the generator 100 which is formed separately from the electric welding gun 10 is used.

In this case, since the generator 100 is manually operated to generate electric power, the moving speed of the movable electrode tip 38 which can be moved via a feed screw mechanism operated under the action of the servomotor 30 is easily increased. Can be adjusted. In other words, the power generated by the generator 100 is
Since the power is extremely smaller than the power supplied from the normal work welding power supply 91 and is generated manually, the fine adjustment of the position of the movable electrode tip 38 and the fixed electrode tip 44 can be performed quickly and reliably. It can be carried out.

Further, if necessary, the generator 100 can be transferred to the vicinity of the electric welding gun 10 by a bogie, and the generator 100 can be easily connected to the electric welding gun 10 via the power line 118. Therefore, the labor required for positioning the movable electrode tip 38 and the fixed electrode tip 44 can be significantly reduced.

The electric welding gun 10 and the generator 100
Are connected to the connection terminals 114a and 116a of the generator 100 using the two power lines 118 and 120.
And one end of each of power lines 118 and 120, and the other end of each of power lines 118 and 120 is connected to first and second power supply connection ports 92 and 94 provided in electric welding gun 10, respectively. (See FIG. 4). Thereby, the generator 100
The electric power generated from the servo motor 30 and the encoder 82
And at the same time.

That is, the power generated by the generator 100 is supplied to the encoder 82 and
2, the rotation angle of the rotor 50 constituting the servo motor 30 is detected by the encoder 82, and the rotation angle of the rotor 50 is calculated by a control device (not shown) connected to the encoder 82. . From the calculation result, the position of the movable electrode tip 38 is determined,
The positioning of the movable electrode tip 38 and the fixed electrode tip 44 may be performed.

[0042]

As described above, according to the present invention,
Since the positioning of a set of electrode tips that constitute the electric welding gun is performed using power from a power source different from the welding power source,
It is possible to perform the positioning operation of the electrode tip quickly and reliably, and it is possible to obtain a unique effect that the power required for the positioning of the electrode tip can be reduced and the operation cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a partially omitted side view showing a robot arm supporting an electric welding gun according to the present embodiment.

FIG. 2 is a partially omitted longitudinal sectional view showing the electric welding gun according to the embodiment.

FIG. 3 is a schematic perspective view showing a generator in the present embodiment.

FIG. 4 is an explanatory diagram showing a state where the electric generator is connected to the electric welding gun.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Electric welding gun 30 ... Servo motor 38 ... Movable electrode tip 44 ... Fixed electrode tip 78 ... Feed screw mechanism 91 ... Power supply for work welding 92 ... First power supply connection port 96 ... Power line for servo motor 100 ... Generator 104 ... shaft 106 ... keyway 108 ... handle 110 ... key 118, 120 ...
Power line

Continued on the front page (72) Inventor Fumio Shibata 1-10-1 Shinsayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. F-term (reference) 4E065 AA08 BA06

Claims (4)

[Claims] 1. A method for aligning a set of electrode tips constituting an electric welding gun, comprising: connecting a generator via a power line to a power supply connection port of the electric welding gun; The electric power is supplied to the electric motor of the electric welding gun, and the electric motor is rotated to move one of the electrode tips of the set of electrode tips to the other of the electrode tips, thereby causing the electrode tips to move closer to each other. A method for positioning an electrode tip, comprising: 2. The method for positioning an electrode tip according to claim 1, wherein power is supplied to said motor by manually rotating said generator to move one electrode tip relative to the other electrode tip. A method for positioning an electrode tip. 3. A positioning device for a set of electrode tips constituting an electric welding gun, comprising: an electric motor; a displacement mechanism driven by the electric motor; and a movable electrode tip detachably attached to the displacement mechanism. When,
A fixed electrode tip opposed to the movable electrode tip, and a generator, wherein the motor is rotated by supplying a different power from the welding power supply to the motor to rotate the motor. An electrode tip positioning device, wherein one of the electrode tips in a set is moved closer to the other electrode tip and the electrode tip is aligned. 4. The electrode tip positioning device according to claim 3, wherein a connection terminal for supplying power for welding to the motor and a connection terminal for supplying power for positioning from the generator. And an electrode chip alignment device, wherein the electrode tip alignment device is used in common.