JP2565770Y2 - Welding head - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a welding head.
More specifically, a change in the pressing force of the welding electrode contacting the work through an elastic member such as a coil spring is captured as an electric signal, and the change in the pressing force is monitored to monitor the work of the work obtained by the welding head. The present invention relates to a welding head capable of determining the quality of welding quality or controlling the quality of a product.

[0002]

2. Description of the Related Art In resistance welding, a large current is applied while two kinds of metal surfaces to be welded are brought into contact and mechanically pressed. For this reason, the contact resistance between the workpieces is significantly higher than the contact resistance of the other metal parts, so that Joule heat is generated. Is the basic principle. In this case, conventionally, in order to obtain a mechanical pressing force, a configuration is adopted in which the electrode abuts on the workpiece under the elastic force of an elastic member such as a coil spring.

[0003]

However, even if a coil spring is used, a constant pressing force is not always applied to a work under a uniform elastic force. Moreover, uniform quality welding is not always performed due to variations in the quality of the work, fluctuations in the current, and the like. Furthermore, when trying to obtain a desired pressing force corresponding to the work by different types of the work,
It is necessary to replace the coil spring provided inside the welding head or to replace the entire welding head with another one. As a result, there is a problem that a considerable amount of time is wasted and a rise in cost is caused, and that production efficiency is not significantly improved.

The present invention has been made to overcome the above-mentioned disadvantages. The present invention takes out a pressing force applied to an electrode head as an electric signal and outputs the electric signal to, for example, a CRT.
In this case, the desired pressing force can be easily obtained by adjusting the knob for adjusting the pressing force when it is changed to another work. As a result, an object of the present invention is to provide a welding head capable of obtaining information for detecting a pressing force for each welding of the welding head and determining whether the welding quality is good or bad.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a cylindrical body, an elastic member housed in the cylindrical body, and a resilient member biased in a predetermined direction by the elastic member. A slide shaft to be moved, a welding electrode fixed to a tip end of the slide shaft that is displaced by the elastic force of the elastic member and pressed against a work to flow a predetermined current, and a pressure adjusting force of the elastic member. the solvent and pressure adjustment knob, at the time of welding is interposed between the pressure adjusting knob and the elastic member
Detecting means for extracting a pressure applied to the contact electrode as an electric signal; and a detecting means provided between the detecting means and the elastic member.
And the pressure applied to the slide shaft is detected.
And a sphere for transmitting to the output means .

[0006]

[Action] The welding electrode itself by contact with the workpiece, the welding electrodes receives a reaction force from the workpiece. This reaction force is transmitted from a resilient member such as a coil spring to the detecting means via a sphere . The detecting means outputs the pressing force in place of the electric signal. The output electric signal is a CRT
The fluctuation of the pressing force can be displayed on the CRT as a waveform, for example.

In this case, if a good range of welding quality is set as a predetermined band, it is determined that a product having welding quality within a standard can be obtained if the waveform of the pressing force falls within the band. You can do it. Also, the welding electrode
Of the welding force applied to the welding electrode
The direction is changed by the sphere to the axis of the detection means.
Therefore, regardless of the angle between the welding electrode and the workpiece,
The pressure can be detected by the detecting means. Sa
In addition, when the elastic member is a coil spring,
The coil spring retracts due to the pressure applied to the electrode
When twisting, a force in the twisting direction is generated.
Direction force is absorbed by the rotation of the sphere,
It is not transmitted to the step. For this reason, the detecting means corrects the pressing force.
It can be detected reliably.

[0008]

Next, a welding head according to the present invention will be described.
Preferred embodiments will be described in detail below with reference to the accompanying drawings.

In the drawings, reference numeral 10 indicates a welding head according to the present invention, and the welding head 10 includes a body 12. The body 12 has an upper body 14 and a lower body 16 and extends from the upper body 14 to the lower body 1.
6, through holes 14a and 14b are provided.
A linear ball bearing 18 is provided in the through hole 14a, and a linear ball bearing 20 is provided in the lower body 16. A slide shaft 22 is provided to penetrate the respective linear ball bearings 18 and 20, and an electrode 24 is fixed to the tip of the slide shaft 22. In the figure, reference numeral 26 indicates an electrode chip.

At the other end of the slide shaft 22,
The first spring receiver 28 is fixed via bolts,
One end of the coil spring 30 is seated on the first spring receiver 28. The coil spring 30 is housed in a recess 32 defined in the upper body 14, and the tip of a cylindrical member 34 is fitted in the recess 32.
As can be easily understood from the figure, the cylindrical member 34 has one end reduced in diameter, and is fixed to the body 12 by screwing a nut 36 into a screw engraved on the outer periphery.

The other end of the coil spring 30 enters the inside of the cylindrical member 34, and a second spring receiver 38 is provided.
To sit down. As shown in the figure, the second spring receiver 38 defines a concave portion 38a at its axial center, and the concave portion 38a
The first ball 40 is seated on a. A spacer 42 is provided at a predetermined distance from the second spring receiver 38. The spacer 42 is provided with a concave portion 42a facing the concave portion 38a, and the upper half of the first ball 40 is seated in the concave portion 42a. The spacer 42 is slidable in a chamber 43 defined in the cylindrical member 34. A recess 42b is defined at the upper end of the spacer 42 along the axis thereof. This concave portion 42b is provided with a detecting means.
The detector 44a of the strain gauge (load cell) 44 having a curved distal end is seated. Therefore, the first bo
40 is the strain gauge 44 and the coil spring
And the power supply 30. A conducting wire 46 is led out from the strain gauge 44, and the pressure applied to the electrode tip 26 via the conducting wire 46 is extracted as an electric signal.

A contact plate 48 is provided above the strain gauge 44. A curved concave portion 48a is provided at an upper end portion of the pressing plate 48, and the second ball 52 is sandwiched between the curved concave portion 50a provided at a distal end portion of the pressure adjusting knob 50.
The pressure adjusting knob 50 is connected to the cylindrical member 34 by a nut 54.
Is firmly held. For this reason,
The second ball 52 is provided between the pressure adjusting knob 50 and the switch.
It is arranged between the drain gauge 44.

The welding head according to the present invention is basically constructed as described above, and its operation and effect will be described below.

The welding head 10 is generally fixed to an arm of a welding robot (not shown). Then, the welding robot makes contact with the electrode 24 against the work under the action of the teaching, and a welding current flows from the electrode tip 26 to the work. On the work side, Joule heat is generated by this current, and since the electrode tip 26 is strongly pressed toward the work side according to the resilience of the coil spring 30, Joule heat is applied to the two stacked works. And both will be welded.

By the way, as welding progresses, the electrode 24 is displaced toward the work. At this time, since the elastic force of the coil spring 30 with respect to the second spring receiver 38 is weakened, the first ball 40 and the spacer 42
The pressure applied to the strain gauge 44 via the pressure change changes. The change in the pressing force is converted into an electric signal via the strain gauge 44 and displayed on a display means (not shown) via the conducting wire 46, for example.

At this time, the first ball 40 and the second ball 5
2 indicates the direction of the pressing force applied to the electrode tip 26 even when the welding head 10 changes its angle.
In the axial direction of the strain gauge 44, and serves to faithfully transmit the fluctuation of the pressing force to the strain gauge 44. Also, when a pressing force is applied to the electrode tip 26, the coil
The spring 30 is retracted, and the coil spring 30
A force is generated in the twisting direction. Further, the electrode tip 26
When the pressure applied to the coil spring 30 decreases,
Generates a force in the twisting direction. However, this screw
The force in the direction in which the first ball 40 rotates
Because it is absorbed, the strain gauge 44
No power is transmitted. Therefore, the fluctuation of the pressing force is reliably transmitted to the strain gauge 44. As a result, by monitoring the output of the strain gauge 44, it is determined what pressing force is applied to the work, and as a result, the welding of the work is performed. It is possible to determine the quality. This means that at the same time each time it is monitored pressure by strain gauge 44, it is possible to determine the quality of the quality continuously against homogeneous types of workpieces flowing in lots information is obtained I do.

[0017]

According to the welding head of the present invention, it is possible to detect the fluctuation of the pressing force transmitted to the detecting means as described above, and to control the welding quality for the workpiece based on the fluctuation. Benefits are obtained. Also for welding
Even if the head changes its angle, the force applied to the welding electrode
The direction of pressure is converted to the axis direction of the detecting means by a sphere.
Therefore, the fluctuation of the pressing force is reliably transmitted to the detecting means.
Furthermore, when the elastic member is a coil spring, welding
Screw on the coil spring due to the pressure applied to the electrode
The force in the direction of twisting is generated.
It is absorbed by the rotation of the body and transmitted to the detection means.
Not. Therefore, the detecting means measures the pressing force with high accuracy.
Can control the welding quality for the workpiece
It is possible.

[Brief description of the drawings]

FIG. 1 is a partially omitted longitudinal sectional view of a welding head according to the present invention.

FIG. 2 is an explanatory side view of the welding head shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Head for welding 12 ... Body 24 ... Electrode 26 ... Electrode tip 30 ... Coil spring 34 ... Cylindrical member 40 ... First ball 42 ... Spacer 44 ... Strain gauge 48 ... This plate 50 ... Knob for pressure adjustment 52 ... Second ball

Claims (1)

(57) [Scope of request for utility model registration] 1. A cylindrical body, an elastic member housed in the cylindrical body, a slide shaft elastically urged in a predetermined direction by the elastic member, and a slide displaced by an elastic force of the elastic member. It is fixed to the distal end of the shaft, and the welding electrode to flow a predetermined current in pressure contact with the workpiece, and a pressure adjusting knob for adjusting the pressure of the elastic member, wherein a pressure adjusting knob and the elastic member Detecting means interposed between the elastic member and a detecting means for extracting a pressing force applied to the welding electrode as an electric signal at the time of welding, and provided between the detecting means and the elastic member;
Transmitting the pressure applied to the ride shaft to the detection means;
And a sphere .