JPS6235585Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an electrode for an electric welding machine used, for example, in multi-point projection welding.

For example, in multi-point projection welding, as shown in FIG. 1, the welding workpiece 36 is welded by applying strong pressure to the welding workpiece 36 and applying electricity between a movable electrode 26 and a fixed electrode 34. . At this time, the movable electrode 26 is connected to the holder 10 connected to a hydraulic or pneumatic cylinder or the like.
It is fixed using bolts 12. The welding current is passed through the holding body 10. Therefore,
The holder 10 and the movable electrode 26 are closely connected to ensure that welding current flows.

By the way, in the above-mentioned conventional electrode for an electric welding machine, for example, an electrically insulating oxide film may be formed on the surface of the welding workpiece 36, or dust or oil may be attached. In this case, the electrical contact between the movable electrode 26 and the welding workpiece 36 was not always good, and as a result, it was often impossible to reliably weld the respective welding points A, A. Furthermore, when welding is performed by applying a welding current while the movable electrode 26 is pressed against the welding workpiece 36 and pressurized, each welding point A, A melts instantaneously.
The side surface of the movable electrode 26 of the welding work 36 rapidly retreats. At this time, the movable electrode 26 must continue to pressurize the welding work 36 by following its rapid retreat. If there is a delay in the follow-up, it will cause welding defects. However,
Since the movable electrode 26 is fixed to the holder 10 and moves together with the holder 10, its inertial mass is very large. Therefore, if the welding work 36 instantly retreats during welding,
There was a problem in that it was difficult to reliably follow the retreat, and as a result, welding defects were likely to occur.

This idea was devised in view of the above-mentioned conventional problems, and its purpose is to weld the workpiece by applying a strong pressure to the welding workpiece and applying electricity between a movable electrode and a fixed electrode. In an electric welding machine, it is possible to always ensure good electrical contact between the welding workpiece and the electrode when welding current is applied, and also to prevent the welding workpiece from instantly retreating from the electrode during welding. To provide an electrode for an electric welding machine which can surely follow this and continue to pressurize the workpiece between the electrodes, thereby reliably preventing the occurrence of welding defects.

In order to achieve the above object, this invention provides an electric welding machine that welds a welding workpiece by sandwiching the welding workpiece between a movable electrode and a fixed electrode and energizing the workpiece. The movable electrode and the holder are mounted so that they can move within a certain range in the axial direction and rotational direction, respectively, and the electrode and the holder are mounted between the movable electrode and the holder. A motion conversion mechanism is provided that converts the relative linear motion between the bodies into a spiral turning motion of the electrode, and a spring is interposed in this motion conversion mechanism so that the electrode is always directed in one direction with respect to the holder. It is characterized by being elastically biased.

Hereinafter, preferred embodiments of this invention will be described based on the drawings. Note that common or corresponding parts in the figures are indicated using the same numbers.

FIG. 2 shows an embodiment of an electrode for an electric welding machine according to this invention. The electrodes shown in the figure include an upper electrode 26 attached to the upper electrode holder 10 via an electrode case 32, and a lower electrode 3 on which a welding work 36 is placed.
4. The upper electrode 26 corresponds to the movable electrode, and the lower electrode 34 corresponds to the fixed electrode.
The electrode case 32 is tightly connected and fixed to the upper electrode holder 10 by mounting bolts 12. The upper electrode 26 is attached to the electrode case 32 of the upper electrode 26 .
They are attached to each other with room for movement within a certain range in the axial direction and rotational direction, respectively. Along with this, the upper electrode 2
6 and the electrode case 32, a motion conversion mechanism 40 that converts the relative linear motion between the electrode 26 and the case 32 into a spiral turning motion of the electrode 26.
is interposed therebetween, and disc springs 14, 14 are interposed in the motion converting mechanism 40, so that the electrode 26 is always elastically biased in one direction with respect to the electrode case 32.

As shown in FIG. 2, the motion conversion mechanism 40 includes a needle thrust bearing 16, a spline shaft 18, a spiral gear 20, an internal spiral gear 22, a retaining ring 24, an upper electrode 26, an upper electrode holding plate 28, etc. It is composed of.

Here, the disc springs 14, 14 are connected to the electrode case 3.
A needle thrust bearing 16 is interposed between the inner ceiling portion of the spiral gear 2 and the upper side of the spiral gear 20, and further between the disc springs 14, 14 and the spiral gear 20. Spline shaft 18
pass through the central axes of the spiral gear 20 and the upper electrode 26, respectively.
is slidably engaged in the vertical direction. Further, the internal spiral gear 22 meshes with the spiral gear portion 27 formed around the outer periphery of the spiral gear 20 and the upper electrode 26, respectively. The retaining ring 24 is attached to the spline shaft 18 and the upper electrode 2
The upward movement range of 6 is restricted. Further, the upper electrode holding plate 28 covers the lower opening of the electrode case 32 with screws 30, 30, and also covers the upper electrode 2
It is also designed to restrict the downward movement range of 6.

Next, the operation of the electrode described above will be explained.
First, when the upper electrode 26 is not driven,
The disc springs 14, 14 press the spiral gear 20 downward. The spiral gear 20 is guided by the internal spiral gear 22 and is pushed downward while rotating. As a result, the spline shaft 18 is also pressed in the turning direction, and this spline shaft 1
8, the upper electrode 26 is constantly pressed in the direction in which it moves downward while rotating. In other words,
The elastic force in the axial direction of the disc springs 14, 14 is converted into an elastic force acting in the spiral turning direction via the spiral gear 20, the internally toothed spiral gear 22, and the spline shaft 18, and this elastic force causes the upper The electrode 26 is always elastically biased in one direction with respect to the electrode case 32. In this state, each member from the holder 10 to the upper electrodes 26 and 32 is in a state of elastic contact, maintaining a close contact state with zero play between each member, and therefore The electrical contact between them is also extremely tight.

Here, when the holder 10 is driven downward by, for example, hydraulic pressure or pneumatic pressure, and the upper electrode 26 is pressed against the welding work 36 to pressurize the work 36, the upper electrode receives the reaction force of this pressurization. 26 will move back slightly (about 2 mm). At this time, the motion conversion mechanism 40
Due to the conversion action, the upper electrode 26 moves backward while turning in a spiral shape, thereby elastically deforming the disc springs 14, 14. As a result, the welding workpiece 36 is pressurized by the elastic restoring force of the disc springs 14, 14.

When welding is performed by applying a welding current under the above-mentioned pressurized state, each welding point A, A melts instantly, and the welding workpiece 36 rapidly retreats downward relative to the upper electrode 26. do. At this time,
The upper electrode 26 is connected to the disc spring 1 via a motion conversion mechanism 40.
4 and 14, the entire body including the holder 10 does not move downward, and the upper electrode 26
Only the welding workpiece 36 is immediately extruded while rotating downward, and continues to pressurize the welding workpiece 36. This allows the welding current to continue flowing to the end, making it possible to obtain a good welding condition.

Then, when welding is completed and the holding body 10 is pulled up, the electrode 26 returns to its original position while rotating.

As described above, the upper electrode 26 moves vertically while rotating in a spiral shape to pressurize the welding work 36, and even in the pressurized state, welding current is applied to move the welding work 36 to each welding point. A, A
What should be noted here is that first, when the upper electrode 26 pressurizes the welding work 36, the upper electrode 26 not only pressurizes the welding work 36; This means that a kind of wiping action is caused by the swirling movement when the pressure is applied. As a result, even if an insulating oxide film has formed on the surface of the welding workpiece 36, or dust or oil has adhered to it, it can be rubbed off and a good electrical contact can always be maintained. It will be possible to secure it. Therefore, it is possible to reliably prevent welding defects caused by poor electrical contact between the electrode and the welding workpiece. Additionally, what should be noted is that even if the welding workpiece 36 suddenly retreats from the electrode during welding, it does not have to wait for the holder 10, which has a large inertial mass, to move; Only the electrode 26 can immediately follow the sudden retreat and continue to pressurize the welding work 36, thereby allowing the welding current to continue flowing to the end and achieving a good welding condition.

Then, from the holding body 10, the upper electrodes 26 and 32
Until then, the elastic force of the disc springs 14, 14 acts to ensure a very good electrical contact state, and thereby the welding current can be passed reliably.

As described above, the electrode for electric welding machines according to this invention can reliably flow welding current without being affected by the electrically insulating oxide film on the surface of the welding workpiece, dirt, oil, etc. It is possible to reliably follow sudden retreat from the electrode during welding of a workpiece, and thereby a good welded product can be obtained with high reproducibility.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a conventional electrode for an electric welder, and FIG. 2 is a sectional view showing an example of an electrode for an electric welder according to this invention. 10... Upper electrode holder, 12... Electrode mounting bolt, 14... Disc spring, 16... Needle thrust bearing, 18... Spline shaft, 20...
Spiral gear, 22... Internal tooth spiral gear,
24... Retaining ring, 26... Upper electrode (movable electrode),
27... Spiral gear part, 28... Upper electrode holding plate, 30... Screw, 32... Electrode case, 34...
...Lower electrode (fixed electrode), 36...Welding work, 4
0...Motion conversion mechanism, A...Welding location.

Claims (1)

[Scope of utility model registration request] In an electric welding machine that welds a welding workpiece by sandwiching the welding workpiece between a movable electrode and a fixed electrode and applying electricity, the movable electrodes are axially and rotationally oriented relative to the electrode holder. The movable electrode and the holder are each mounted with room for movement within a certain range, and the relative linear movement between the electrode and the holder is controlled by the spiral motion of the electrode. A motion converting mechanism that converts the motion into a circular turning motion is interposed, and a spring is interposed in the motion converting mechanism so that the electrode is always elastically biased in one direction with respect to the holder. Electrodes for welding machines.