JP2570945Y2 - Force measuring device for resistance welding machine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a pressing force in a resistance welding machine.

[0002]

2. Description of the Related Art In resistance welding, a pressing force is a welding current,
One of the three major welding conditions that affect welding quality along with energizing time
It is one. Conventionally, as a device for measuring the pressing force of a resistance welding machine, a pressing force sensor composed of a load cell or the like is inserted between a pair of welding electrodes instead of a workpiece to be welded, and the pressing force sensor is connected to the pressing force sensor through the welding electrodes. A pressure gauge that displays the applied pressure by a meter is used.

[0003] As shown in FIG.
0 is a disk-shaped pressure sensor 10 with a built-in load cell.
2 is attached to the tip of the handle 104. The central protrusions 102a on both sides of the sensor 102 are pressure-sensitive portions directly connected to the built-in load cell. A cable 106 protruding from the base end of the handle 104 sends an output signal of the load cell to a measurement value calculation display section of the main body (not shown).

As shown in FIG. 7, when the pressure of the resistance welding machine is measured by the pressure gauge 100, a measurer or an operator (not shown) grasps the handle 104 by hand and activates the sensor 102. Inserted between the pair of welding electrodes 108, 110,
The welding circuit is stopped, no welding current is applied, and the pressing mechanism 112
Are operated under the same conditions as during welding, and the welding electrodes 108, 11
The sensor 102 is sandwiched and pressurized between 0. Then,
An electric signal corresponding to the pressure applied to the sensor 102 is output from the load cell in the sensor 102, and the measured value of the pressure is displayed on the display unit of the main body 114.

[0005]

In the pressure gauge 100 as described above, the tips of the welding electrodes 108 and 110 are shifted from the pressure sensing portion 102a of the sensor 102 and come into contact therewith.
Alternatively, if the contact is made in an oblique direction, the pressure cannot be measured correctly. Therefore, the operator is required to make the pressure-sensitive portion 102a of the sensor 102 at the correct angle with the welding electrode 10a.
Pressing force gauge 1 well so that it is sandwiched between 8,110
00 must be handled. In this regard, the resistance welding machine shown in FIG. 7 is of a stationary type in which the upper welding electrode 108 only moves up and down when pressurized, and the other parts are always stationary, so that the operator holds the handle 104 by the gripping operation. And sensor 1
It is not so difficult to insert 02 at the correct position and angle between the welding electrodes 108 and 110.

However, a C-shaped welding gun 1 as shown in FIG.
In a portable resistance welding machine mounted on robots 122 and 132, such as an X-type welding gun 130 as shown in FIG.
6) Since the position and orientation of (134, 136) are indeterminate, the sensor 102 is connected to the welding electrodes (124, 126), (1).
34, 136) is an extremely difficult task for the operator to insert and carry at the correct position and angle.
In particular, in the case of the X-type welding gun 130, both welding electrodes 13 are used.
4, 136, the positioning of the sensor 102 is extremely difficult, and the operator's hand erroneously moves the electrodes 134,
There was also a risk of being pinched by 136. Therefore, the conventional pressure gauge 100 cannot be used for measuring the pressure in a portable resistance welding machine.

In the conventional pressure gauge 100, a sensor 10 is used instead of a work (workpiece) to be actually welded.
2 is inserted and sandwiched between the welding electrodes, but the sensor 102 is made of a rigid body so as not to be deformed and has a thickness of about 20 mm.
This is an object to be pressed different from a general work having a plate thickness of about 1 mm. For this reason, the degree of contact of the welding electrode with the sensor 102 is different from that of the workpiece, and therefore, the degree of pressing is also different, and there is a problem that the difference appears as an error in the measured value.

The present invention has been made in view of such a problem, and does not require any special labor of an operator, and can measure a pressing force safely, easily, and accurately even with a portable resistance welding machine. It is an object of the present invention to provide a simple and general-purpose pressing force measuring device capable of measuring a pressing force on an actual welded portion.

[0009]

According to one aspect of the present invention, there is provided a pressure measuring device for measuring a pressing force in a resistance welding machine. A tip base having a mounting portion for being detachably attached to a tip holder at the tip of the welding electrode; a tip intermediate portion provided by being connected to an upper surface of the tip base; and a tip intermediate portion. It is provided with a chip head provided to be connected to the upper end and having an upper surface for making contact with an object to be pressed, and a pressure sensor attached to the chip middle part. According to a second aspect of the present invention, in the configuration of the first aspect of the present invention, the pressing force sensor includes a first strain gauge for detecting a pressing force in a chip longitudinal direction; A second strain gauge for detecting a pressing force in a direction orthogonal to the first direction.

A third aspect of the present invention is a pressing force measuring device for measuring a pressing force in a resistance welding machine, wherein the mounting device is detachably attached to a tip holder at a tip portion of a welding electrode. A chip base end having a portion, a chip intermediate portion provided by being connected to the upper surface of the chip base end, and a chip intermediate portion provided to be connected to the upper end of the chip intermediate portion, for contacting the object to be pressed. A chip head having an upper surface, a pressure sensor attached to the chip intermediate portion, a cover provided around the chip intermediate portion to protect the pressure sensor, the chip intermediate portion and the cover And an insulating rubber member filled between the two. According to a fourth aspect of the present invention, in the configuration of the fourth aspect, the insulating rubber member is made of silicone rubber. According to a fifth aspect of the present invention, in the configuration of the first aspect, a current is applied between the object to be pressed and the tip holder, which is in contact with the upper surface of the tip head. An insulating member is provided at the tip mounting portion at the base end portion of the tip to prevent the occurrence of the problem. According to a sixth aspect of the present invention, in the configuration of the first aspect of the present invention, a cooling water supply pipe is provided inside the tip holder, and the tip mounting portion at the base end of the tip is provided with the cooling water supply. It is characterized by having a surface for receiving the cooling water jetted from the pipe.

When a pressing force is applied to the object to be pressurized, the pressure measuring device of the present invention receives a reaction from the object to be pressurized. This reaction is transmitted to the middle portion of the chip via the head of the chip, and an electric signal corresponding to the magnitude of the reaction, that is, the pressing force is generated by the pressure sensor at the middle portion of the chip. The pressing force sensor detects the pressing force in the chip longitudinal direction by the first strain gauge, and detects the pressing force in the direction orthogonal to the chip longitudinal direction by the second strain gauge, thereby detecting the pressing force in both directions. And the vector-like pressing force can be measured. Also, by filling an insulating rubber member (for example, silicone rubber) between the chip intermediate portion and the cover, the pressure sensor is physically and electrically protected, and a reliable pressure measurement can be ensured. You.

[0012]

EXAMPLES Hereinafter, an embodiment of the present invention with reference to FIGS. 1 to 4 are views for explaining an embodiment of a pressing force measuring device according to the present invention, FIG. 1 is a perspective view showing an external configuration of the pressing force measuring device, and FIG. FIG. 3 is an exploded perspective view showing the internal configuration of the apparatus, FIG. 3 is a longitudinal sectional view showing the internal configuration of the applied pressure measuring device in more detail, and FIG. 4 is a side view showing an example of use of the applied pressure measuring device. .

As shown in FIG. 1, a pressure measuring device 10 according to the present embodiment is a cap-tip type device which is detachably attached to a tip holder 12 of a resistance welding machine. Similarly to the cylindrical body 1
4 and a spherical chip head 16. However, a cable 18 for transmitting a sensor output signal protrudes from the side surface of the body 14.

As shown in FIG. 2, the body 14 is
And a cylindrical cover 22. The cable outlet 24 is provided on the cover 22 side. The main body 20 is entirely made of metal, for example, stainless steel, and has the spherical chip head 16, a quadrangular prism-shaped chip intermediate portion 26, and a cylindrical chip base end portion 28. For example, resistance strain gauges 30A, 30B, 30C, and 30D are affixed to each side surface of the chip intermediate portion 26 as a strain gauge. Each resistance wire strain gauge 30A~30D is Wheel bets Stone-on thin substrates of paper or plastic, etc. by extending the resistance wire, such as nickel alloy (gauge wire) in a predetermined pattern
When each side surface (measurement surface) of the chip intermediate portion 26 is distorted by the applied pressure, the length, diameter, and specific resistance of the resistance wire change in accordance with the distortion. The corresponding electric signal can be taken out. In this embodiment, not only the pressure parallel to the axial direction but also the pressure perpendicular to the axial direction can be measured simultaneously.
For example, the gauges 30A and 30B are attached in a direction for detecting a vertical pressing force, and the gauges 30C and 30D are attached in a direction for detecting a horizontal pressing force.

As shown in FIG. 3, each of the gauges 30A to 30A
The D output lines 32A to 32D are connected to the cable 18. Between the tip intermediate part 26 and the cover 22, an insulating filler e.g. silicone over emissions rubber 25 is filled, together with the cover 22 is attached to the body 20 by the filling material, the interior of the gauge 30A~30D Physically and electrically protected. Inner peripheral surface 28 of tip base end 28
a is formed in a tapered shape such that the hole diameter becomes smaller toward the inner side, and the tapered hole is fitted into the tapered tip portion 12a of the tip holder 12, thereby forming a cap-tip type main force measuring device. 10 is detachably attached to the chip holder 12. Tip base end 28
An insulating material 34 is affixed to the tapered inner peripheral surface 28a, and the pressure measuring device 10 is electrically insulated from the tip holder 12 by the insulating material 34.

The tip holder 12 is a hollow tube made of a metal having high conductivity, for example, copper, and a cooling water supply tube 36 for water-cooling an original cap chip, that is, an electrode chip, is coaxially provided at a tip end thereof. . At the time of welding current, the cooling water spouted from the cooling water supply pipe 36 hits the bottom surface of the electrode tip, passes through the inside of the tip holder 12, and is collected by a cooling water collecting part (not shown).

As shown in FIG. 4, a pressing force measuring apparatus 10 according to the present embodiment includes one of a pair of tip holders 12A and 12B, for example, a lower tip holder 1 in a resistance welding machine.
It is detachably attached to 2B. An electrode tip 40 is detachably attached to the other (upper) tip holder 12A as a normal cap tip. When measuring the pressing force, as shown in FIG. 4, the workpieces 42 and 44 are inserted between the cap chips 10 and 40 as the workpieces to be pressurized, and the welding current is not applied, and the pressing mechanism (FIG. 4) is used. (Not shown) may be operated under the same conditions as during welding. Then, the upper arm 46 integrally connected to the movable portion of the pressing mechanism is lowered, and the upper cap chip 40 presses the workpieces 42 and 44 against the lower cap chip 10. Lower cap chip 1
0 receives the workpieces 42 and 44 because it is fixed and supported by the fixed lower arm 48. In this way, the same pressing force as that at the time of welding is applied to the workpieces 42 and 44 via the cap tips 40 and 10.

When the pressing force is applied to the workpieces 42 and 44 in this manner, in the present pressing force measuring device 10 as the lower cap tip, the same pressing force as that for the workpieces 42 and 44 is applied to the tip head. Resistance strain gauge 30 attached to the portion 16 and attached to the four side surfaces of the chip middle portion 26
From A, 30B, 30C, and 30D, an electric signal indicating the pressing force in the axial direction or the pressing force in the horizontal direction can be obtained. These pressure detection signals are sent to the calculation unit of the measurement device main body (not shown) via the cable 18 and the measurement value of the pressure is displayed on the display unit of the measurement value main body.

As described above, in the present embodiment, instead of the electrode tip, the cap tip type pressure measuring device 10 having a shape similar to the electrode tip is mounted on one (for example, the lower) tip holder 12B, and the actual object is mounted. The workpieces 42 and 44 are pressurized through the two cap tips 40 and 10 under the same conditions as at the time of welding, and the applied pressure is measured by the cap tip type pressure measuring device 1.
Measure by 0. Therefore, it is not necessary for an operator to perform a manual operation such as gripping the pressure sensor when measuring the pressure, and the measured pressure can always be applied to the strain gauge at an accurate angle.

In the pressure measuring device 10 of the present embodiment, the spherical tip portion 16 comes into contact with the workpieces 42 and 44, so that the pressure applied to the workpieces 42 and 44 is oblique. Even if there is, the pressure can be directly sensed as a vector-like pressing force, and the pressure can be directly measured as a vector-like pressing force by the four orthogonal resistance wire strain gauges 30A to 30D. Therefore, it is possible to obtain a more accurate pressure measurement value.

Further, even when a welding circuit is operated incorrectly and a voltage is applied between the two chip holders 12A and 12B at the time of measuring the pressing force, the insulating material 34 provided on the inner peripheral surface 28a of the chip base end portion 28 can be used. Since the pressing force measuring device 10 and the lower tip holder 12A are insulated, no current flows and no welding current flows. Therefore, the present pressure measuring device 10 and the workpieces 42 and 44 are protected.

In FIG. 4, when the pressing force measurement is not performed, the pressing force measuring device 1
0 is removed, and the same electrode tip as the upper electrode tip 40 is mounted on the lower tip holder 12.

FIG. 4 shows an example in which the cap tip type pressure measuring device 10 according to the present embodiment is used in a stationary resistance welding machine. However, a portable resistance welding machine such as a C-type welding gun or an X-type welding gun is used. In this case, it is only necessary to mount the chip holder on the chip holder in the same manner as in the stationary type, and the same operation and effect as described above can be obtained.

Although a preferred embodiment has been described above, various modifications and changes can be made within the technical scope of the present invention. For example, in the above-described embodiment, the insulating material 34 is provided on the inner peripheral surface 28a of the chip base end portion 28 to be fitted to the chip holder as a means for preventing the current from flowing during the pressure measurement. body 20 and the cover 22 as shown in)
An insulating material 46 is provided at the joint with the chip head 16 or the chip head 16 which comes into contact with the object to be pressed as shown in FIG.
May be provided with an insulating material 48 at the front end. Further, the shape of the chip intermediate portion 26 is not limited to a quadrangular prism, but may be a triangular prism,
Other polygonal prisms such as a pentagonal prism may be used, or a cylindrical shape may be used, and the number, position, and direction of the strain gauges may be arbitrarily selected. As the strain gauge, another type of gauge such as a semiconductor strain gauge can be used instead of the resistance wire strain gauge. Also,
It is also possible to provide a pressure sensor other than a strain gauge on the cap chip. Further, a structure in which the tip base end portion 28 is attached to the tip holder by screwing may be adopted.

[0025]

As described above, according to the pressure measuring device for a resistance welding machine of the present invention, the pressure sensor is provided on the cap chip, and the pressure is applied to the actual workpiece through the cap chip. The force is measured by the force sensor in the cap chip, so that not only the fixed resistance welding machine but also the portable resistance welding machine can be used safely and safely without troublesome workers. Pressing force can be measured easily and with high accuracy.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an external configuration of a pressing force measuring device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing an internal configuration of a pressing force measuring device in the embodiment.

FIG. 3 is a longitudinal sectional view showing the internal configuration of the pressing force measuring device in the embodiment in more detail.

FIG. 4 is a side view showing an example of a use mode of the pressing force measuring device in the embodiment.

FIG. 5 is a perspective view showing a modified example of the insulating function of the pressing force measuring device in the embodiment.

FIG. 6 is a perspective view showing an external configuration of a pressure gauge as a conventional pressure measurement device.

FIG. 7 is a perspective view showing a usage mode of a conventional pressure gauge in a stationary resistance welding machine.

FIG. 8 is a perspective view showing a usage mode of a conventional pressure gauge in a C-type welding gun mounted on a robot.

FIG. 9 is a perspective view showing a usage mode of a conventional pressure gauge in an X-type welding gun mounted on a robot.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Cap-chip type force measuring device 12 Tip holder 16 Tip head 18 Cable 20 Main body 22 Cover 26 Tip middle part 28 Tip base end 30A-30D Resistance wire strain gauge 34 Insulation material

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-148476 (JP, A) JP-A 64-29726 (JP, A) JP-A-3-36369 (JP, U) JP-A 57- 166142 (JP, U) Japanese Utility Model 5-84479 (JP, U)

Claims (6)

(57) [Scope of request for utility model registration] 1. A pressure force measuring device for measuring a pressure force in a resistance welding machine, comprising: a tip base end portion having an attachment portion for detachably attaching to a tip holder at a tip end portion of a welding electrode; A chip intermediate portion provided to be connected to an upper surface of the chip base end portion, a chip head provided to be connected to an upper end of the chip intermediate portion, and having an upper surface for contacting an object to be pressed; A pressure measuring device, comprising: a pressure sensor attached to an intermediate portion of the chip. 2. The pressure sensor according to claim 1, wherein the pressure sensor has a first strain gauge for detecting a pressure in a chip longitudinal direction, and a second strain gauge for detecting a pressure in a direction orthogonal to the chip longitudinal direction. The pressure measuring device according to claim 1, further comprising: 3. A pressure force measuring device for measuring a pressure force in a resistance welding machine, comprising: a tip base end portion having an attachment portion for detachably attaching to a tip holder at a tip end portion of a welding electrode; A chip intermediate portion provided to be connected to an upper surface of the chip base end portion, a chip head provided to be connected to an upper end of the chip intermediate portion, and having an upper surface for contacting an object to be pressed; A pressure sensor attached to the chip intermediate portion; a cover provided around the chip intermediate portion to protect the pressure sensor; and an insulating material filled between the chip intermediate portion and the cover. A pressure measuring device comprising a rubber member. 4. The pressure measuring device according to claim 3, wherein the insulating rubber member is a silicone rubber. 5. An insulative member for preventing electricity from flowing between the object to be pressed and the chip holder in contact with the upper surface of the chip head is provided at the chip mounting portion at the base end of the chip. The pressure measuring device according to any one of claims 1 to 4, wherein 6. A cooling water supply pipe is provided inside the chip holder, and a chip mounting portion at a base end of the chip has a surface for receiving cooling water jetted from the cooling water supply pipe. The pressure measuring device according to claim 1.