JP3360538B2 - Arc welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc welding apparatus for feeding a welding wire to a portion to be welded by using a welding power source and a wire feeding device and performing welding by using arc heat.

[0002]

2. Description of the Related Art In recent years, arc welding apparatuses have become more sophisticated and some of them incorporate microcomputers.
In order to improve the efficiency of the welding operation, it is desired to ensure a low spatter arc start. In order to improve the performance of the arc start, various devices have hitherto been devised.

[0003] Hereinafter, an arc welding apparatus in which control of the wire feeding speed of the welding wire feeding apparatus is devised will be described with reference to FIG.

That is, in the conventional arc welding apparatus, a welding output switch 1 for opening and closing a welding output, and a steady motor rotation speed setting unit for setting the rotation speed of a feed motor 3 of a welding wire 2 during steady welding. 4, a first initial motor speed setting unit 5 for setting the speed of the feed motor 3 of the welding wire 2 from when the welding output switch 1 is turned on until the welding current flows, A motor speed setting signal switching circuit for receiving signals from a welding current detecting circuit 6 to be detected and a signal from the welding output switch 1 and switching signals between a steady motor speed setting unit 4 and a first initial motor speed setting unit 5. 7, a motor rotation speed control circuit 8 switched by a signal of the motor rotation speed setting signal switching circuit 7, and a motor 3 for feeding the welding wire 2 driven by an output signal of the motor rotation speed control circuit 8. It is obtained; and a feed roller 9 feeding directly connected to the force axis. Reference numeral 10 denotes a base material to be subjected to arc welding.

[0005] The wire feed speed at the time of arc start of this conventional arc welding apparatus is controlled as shown in a time chart of FIG.

That is, the feed motor 3 of the welding wire 2 starts rotating at the rotation speed set by the first initial motor rotation speed setting section 5 in response to the start signal of the welding output switch 1. When the welding current is detected by the welding current detection circuit 6 that detects the welding current, the motor rotation speed is set by the steady motor rotation speed setting unit 4 from the rotation speed set by the first initial motor rotation speed setting unit 5. It is switched to the motor speed.

That is, the wire feed speed at the time of the arc start of the conventional arc welding apparatus is switched from the slow down speed to the steady speed when the welding current is detected, thereby improving the arc start performance.

[0008]

However, the arc start of the conventional arc welding apparatus has not been reliable.
In particular, when an arc start fails at a low current, the number of revolutions set by the steady motor revolution number setting unit 4 is small.

Further, when welding is performed at a low current, the tip of the welding wire 2 is largely repelled at the time of arc start, and a molten piece of the melted wire is scattered near the welding start end, so that the welding result is greatly impaired. There was a point.

According to the present invention, the arc start of the arc welding apparatus is ensured, and particularly, the time required for restarting the arc welding apparatus is shortened, the amount of the tip of the welding wire flicked off at the time of the arc start is reduced, and the melting of the wire is started. It is an object of the present invention to prevent a piece from scattering near a welding start end.

[0011]

In order to achieve this object, according to the present invention, in addition to the circuit configuration of a conventional arc welding apparatus, the rotation of a motor for feeding a welding wire for a predetermined time after a welding current has flowed. It is provided with a second initial motor speed setting unit for setting the number, and a timer circuit for generating an ON signal for a certain time in response to a signal from the current detection circuit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With the above configuration, the arc welding apparatus according to the present invention provides a rotation speed set by a first initial motor rotation speed setting unit from when the welding output switch is turned on until a welding current flows. From the first slowdown speed), the motor speed (second slowdown speed) set by the second initial motor speed setting unit is switched for a certain time after the welding current flows, and the time period of the timer circuit 11 is changed. After the end, the rotation speed (steady speed) set by the steady motor speed setting unit 4 is sequentially switched, and the second slowdown speed is set higher than the steady speed. Even if a failure occurs at the time of the arc start, the time required for the tip of the wire to reach the base again again is reduced.

An embodiment of the present invention will be described below with reference to FIG. 1, reference numerals 1 to 6, 8 to 10 are the same as those of the conventional example shown in FIG.

An arc welding apparatus according to an embodiment of the present invention includes a welding output switch 1 for opening and closing a welding output, and a stationary motor rotation for setting the rotation speed of a feed motor 3 for a welding wire 12 during steady welding. Number setting unit 4 and welding output switch 1
Wire 1 from when the welding is turned on until the welding current flows
A first initial motor rotation speed setting unit 5 for setting the rotation speed of the feed motor 3 and a second rotation speed setting unit 5 for setting the rotation speed of the feed motor 3 for the welding wire 12 for a predetermined time after the welding current flows.
An initial motor rotation number setting unit 12, a current detection circuit 6 for detecting a welding current, a timer circuit 11 for receiving a signal from the welding current circuit 6 and generating an ON signal for a certain period of time,
Upon receiving signals from the reception output switch 1, the welding current detection circuit 6, and the timer circuit 11, the stationary motor speed setting unit 4, the first initial motor speed setting unit 5, and the second initial motor speed setting A motor rotation setting signal switching circuit 13 for switching a setting signal from the section 12; a motor rotation speed control circuit 8; a feed motor 3 driven by the motor rotation speed control circuit 8; And a feed roller 9 directly connected to the output shaft.

The wire feed speed at the time of arc start of the arc welding apparatus according to the present embodiment is controlled as shown in a time chart of FIG. That is, in the arc welding apparatus of the present embodiment, the motor rotation speed (first rotation speed) set by the first initial motor rotation speed setting unit 5 from when the welding output switch 1 is turned on until the welding current flows.
The motor rotation speed (second slowdown speed) set by the second initial motor rotation speed setting unit 12 for a certain period of time after the welding current flows, and after the time period of the timer circuit 11 ends. Is sequentially set to the motor rotation speed (steady speed) set by the steady motor rotation setting part 4, and a fixed time set by the timer circuit 11 after the welding current flows is set at the second slowdown speed for welding. Send wire 2,
After the time limit of the timer circuit 11 is over, the steady speed is set.

As described above, in the arc welding apparatus according to the embodiment of the present invention, the control of the wire feeding speed of the wire feeding device is performed until the welding wire 2 reaches the base metal 10 and reaches the steady speed. Since the slowdown speed of 2 is set to the number of revolutions at which the arc start is most easily performed, the arc start is assured, and the time required for the welding wire to reach the base metal at the time of the arc start and to transition to the arc is extremely long. Even when welding is performed at a low current (80 A to 120 A) that requires a small amount of arc start failures, a reliable arc start welding current range (150 A) only at the start.
~ 250A).

[0017]

According to the arc welding apparatus of the present invention, since the control of the wire feeding speed of the wire feeding device is set to the two steps of the slowdown speed only at the time of starting, the arc start can be surely performed. Even if it fails at the start, it does not take long time to restart, and even when welding at low current where arc start failure often occurs,
At the start-up, the welding is started under a reliable arc start welding condition, so that an excellent effect is obtained that the wire melted pieces are less scattered near the welding start end.

[Brief description of the drawings]

FIG. 1 is a block diagram of an arc welding apparatus according to an embodiment of the present invention.

FIG. 2 is a time chart of a wire feeding speed at the time of arc start in the embodiment.

FIG. 3 is a block diagram of a conventional arc welding apparatus.

FIG. 4 is a time chart of a conventional wire feeding speed at the time of arc start.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Welding output switch 4 Steady motor rotation speed setting part 5 First initial motor rotation speed setting part 6 Welding current detection circuit 7 Motor rotation speed setting signal switching circuit 8 Motor rotation speed control circuit 11 Timer circuit 12 Second initial motor Rotation speed setting unit 13 Motor rotation speed setting signal switching circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23K 9/12 B23K 9/067 B23K 9/10

Claims (1)

(57) [Claims] A welding output switch for opening and closing a welding output;
A welding current detection circuit for detecting a welding current, a timer circuit for receiving a signal from the welding current detection circuit to generate an ON signal for a certain period of time, and setting a rotation speed of a welding wire feed motor during steady welding. A first motor rotation speed setting unit for setting a rotation speed of a feed motor of a welding wire from when the welding output switch is turned on until a welding current flows, and a welding current. Receiving a signal from the welding output switch, the welding current detection circuit, and the timer circuit, a second initial motor rotation speed setting unit that sets the rotation speed of the feeding motor for the welding wire for a certain period of time after the flow. A motor speed setting signal switching circuit for switching setting signals from the steady motor speed setting unit, the first initial motor speed setting unit, and the second initial motor speed setting unit; The welding current flows at the motor rotation speed (first slowdown speed) set by the first motor rotation speed setting unit until the welding current flows after the welding output switch is turned on. From the motor rotation speed (second slowdown speed) set by the second initial motor rotation speed setting unit for a certain period of time, and the motor rotation speed set by the steady motor rotation speed setting unit after the time limit of the timer circuit ends ( An arc welding apparatus in which the second slowdown speed is set to be higher than the steady speed.