JPH0516951B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a resistance welding machine suitable for welding a plurality of types of workpieces.

(Prior art) In a resistance welding machine for spot welding, the workpiece is placed on a lower electrode fixed to a frame, and the upper electrode is lowered from above using a pressure cylinder to apply electricity while pressurizing the workpiece. Usually, welding is carried out using the welding method (for example, Japanese Utility Model Application No. 60-34384). Conventionally, resistance welding was performed by replacing these electrodes depending on the type of workpiece, but in factories that produce a wide variety of products in small quantities, electrodes must be replaced frequently, and this step The time required for replacement was not negligible.

(Problems to be Solved by the Invention) The present invention aims to solve the above-mentioned conventional problems and provide a resistance welding machine that can replace the electrode in an extremely short time depending on the type of workpiece. It was completed as.

(Means for Solving the Problems) The present invention has a rotating shaft with an electrode holding horn attached to the tip thereof rotatably supported by a bearing, and a rotating mechanism for reciprocating rotation is connected to this rotating shaft via a gear. At the same time, a plurality of electrodes of different types are protruded from the outer circumferential surface of this electrode holding horn, which are alternately fixed in vertical positions by a rotating mechanism, and are further pressed toward the rotating shaft by a spring around the outer circumference of the rotating shaft. The device is characterized in that it is provided with a power supply metal that can

(Embodiments) Next, the present invention will be described in more detail with reference to illustrated embodiments.

1 is a frame of a resistance welding machine, 2 and 3 are bearings erected on the frame 1, and 4 is a horizontal rotating shaft rotatably supported by the bearings 2 and 3. A plurality of electrode holding horns 5 extending in the radial direction are attached to one end of the rotating shaft 4. Also, the rotation axis 4
The electrode holding horn 5 can be rotated reciprocally by this rotation mechanism 7.

As clearly shown in FIG. 3, a plurality of electrodes 9 and 10 of different types are provided on the outer peripheral surface of the electrode holding horn 5 in a protruding manner. In this embodiment, these electrodes are all lower electrodes, and the electrode 9 is an electrode for welding a projection nut, which has a pin 12 with a spring 11 inside, as shown in cross section in FIG. 10 is an electrode for bolt welding. In the embodiment, two electrodes 9 and 10 are provided protruding from the outer peripheral surface of the electrode holding horn 5 at an interval of 90 degrees, but it goes without saying that the number of electrodes and the mounting positions can be increased as appropriate.

In addition, in the embodiment, a rotation angle regulating device consisting of a stopper arm 23 and a stopper block 24 for regulating the rotation angle to 90 degrees is attached to the other end of the rotating shaft 4 as shown in FIG. Needless to say, if this changes, the rotation angle regulating device must also be changed. Each electrode 9, 10 is attached to the electrode holding horn 5 by a holding bolt 13, and cooling pipes 14, 15 are provided in the center thereof, and the lower ends thereof are transparently installed inside the rotating shaft 4. The cooling water supply hole 16 and the cooling water discharge hole 17 communicate with each other as shown in FIGS. 1 and 3. That is, the cooling water supplied from the cooling water supply hole 16 first reaches the electrode 10.
It flows through the inside of the cooling pipe 15 to cool the electrode 10, and the third
It enters the inside of the cooling pipe 14 of the electrode 9 as shown in the figure. After cooling the electrode 9, the cooling pipe 1
4 and is discharged from the cooling water discharge hole 17 of the rotary shaft 4.

Note that 18 is a power supply metal provided at an intermediate position between the bearings 2 and 3, and is pressed against the outer circumferential surface of the rotating shaft 4 by the force of the spring 19, and the conductive bar 20
This is for supplying the current supplied by the electrode to the electrode holding horn 5 and the electrodes 9 and 10 via the rotating shaft 4. Further, 21 is a nipple for supplying cooling water to the power supply metal 18, and 22 is a nipple for draining water.

(Function) As shown in FIG. 1, in this structure, the electrode 9 is fixed in a vertical position, objects to be welded such as a steel plate and a projection nut are supplied to the upper surface of the electrode 9, and the upper electrode 30 is is lowered to sandwich the part to be welded between the electrode 9 and the upper electrode 30, for example.
Resistance welding is performed by applying a current of about 10,000 to 20,000 A as in the conventional method.

However, the resistance welding machine of the present invention operates the rotation mechanism 7 to rotate the electrode holding horn 5 together with the rotating shaft 4 in a horizontal plane, thereby removing the other electrodes protruding from the outer peripheral surface of the electrode holding horn 5. Since the electrode 10 can be replaced with an electrode 9 and fixed in a vertical position, the electrode 9 and the electrode 10 can be replaced in a very short time even when the objects to be welded are changed to a steel plate and a bolt, for example. Also, when such a rotating shaft 4 is rotated, the power feeding metal 18 provided on the outer periphery of the rotating shaft 4 is pressed toward the rotating shaft 4 by the spring 19, and the electrode 9 is connected to the rotating shaft 4 through the rotating shaft 4.
It is possible to reliably supply power to the

Therefore, according to the present invention, when electrodes need to be replaced frequently, such as in a line where projection nuts and bolts are welded to steel plates, the time required for setup changes can be significantly reduced. It becomes possible. During resistance welding, the electrodes 9, 10 are reliably supported vertically by the rotation mechanism 7 and the rotation angle regulating device, so resistance welding can be performed accurately as in the conventional method, and the electrodes 9, 10 and Since the power supply metal 18 is cooled by cooling water, damage due to heat generation is prevented.

Although the above explanation focuses on the lower electrode, it is also within the scope of the present invention to adopt a similar mechanism for the upper electrode, and it is also possible to adopt such a mechanism for both the upper and lower electrodes. Needless to say, it's okay.

(Effects of the Invention) As is clear from the above description, the present invention enables the resistance welding electrode to be instantly changed depending on the object to be welded, and therefore is suitable for factories that carry out high-mix, low-volume production. If used when the workpiece to be welded changes frequently, as in the case of frequent changes, it has the advantage that the time required for changeover can be significantly reduced. Therefore, the present invention makes an extremely large contribution to the industry as a resistance welding machine that solves the conventional problems.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, FIG. 2 is a partially cutaway plan view thereof, FIG. 3 is a left side view thereof, and FIG. 4 is a right side view thereof. 2, 3: Bearing, 4: Rotating shaft, 5: Electrode holding horn, 7: Rotating mechanism, 9, 10: Electrode, 18: Power supply metal, 19: Spring.

Claims (1)

[Claims] 1. A rotating shaft 4 with an electrode holding horn 5 attached to the tip thereof is rotatably supported by bearings 2 and 3, and a rotating mechanism 7 for reciprocating rotation is connected to this rotating shaft 4 via a gear, and this electrode holding horn 5 is attached to the rotating shaft 4. horn 5
A plurality of electrodes 9 and 10 of different types are protruded from the outer circumference of the rotary shaft 4 and are alternately fixed in vertical positions by a rotating mechanism 7, and are further pressed toward the outer circumference of the rotary shaft 4 by a spring 19. A resistance welding machine characterized by being provided with a power supply metal 18.