JP2018167302A - Quality determination device of electrode for spot welding - Google Patents

Abstract

To provide a quality determination device of an electrode for spot welding, which is suitable for determining accurately the quality of a polishing state of an electrode tip.SOLUTION: A quality determination device A1 for determining the quality of a polishing state of the tip part of electrode for spot welding, includes a current carrying medium 2 abutting on tips of a pair of electrodes 6, 6, a measuring part 3A for measuring a measurement value on the current carrying medium 2 at a current carrying time to the current carrying medium 2 through the pair of electrodes 6, 6, and a determination part 4 for determining the quality of a polishing state of the pair of electrodes 6, 6 based on the measurement value on the current carrying medium 2 measured by the measuring part 3A.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for determining the quality of a polished state of an electrode tip for spot welding.

  Electrodes used for spot welding are subjected to high pressure during welding and high current flows, so the tip wears out during use, forming a flat part, and the metal component of the welding object adheres. Or If the welding operation is continued in this state, the current density is lowered and a predetermined Joule heat cannot be obtained, resulting in poor welding. In order to prevent such poor welding due to electrode deterioration, the tip of the electrode is cut and polished at regular intervals in order to return the tip of the electrode to a predetermined curved surface shape.

  The electrode tip is polished using a polishing apparatus disposed near the welding robot. The polishing apparatus has a cutter holder in which, for example, a cutter is mounted in a recessed portion into which an electrode tip can be inserted. At the time of electrode polishing, the cutter holder is rotated in a certain direction by a driving force of a motor while the cutter holder is pressed and sandwiched by a pair of electrodes provided at the tip of the welding gun.

  An apparatus for automatically determining the polishing state of the electrode tip shape after polishing work is disclosed (see, for example, Patent Document 1). In this document, light is applied to the center of the electrode tip after polishing, and the quality of the electrode tip shape is determined based on the amount of reflected light. According to the determination method disclosed in Patent Document 1, the quality determination is performed based on the light reflection characteristics at the center of the electrode tip, so that the polishing state can be accurately determined in a relatively narrow range at the center of the electrode tip. . In the polishing of the electrode tip, it is important that the rounded tip shape is more accurately restored. However, in the determination method described in Patent Document 1, the peripheral part surrounding the central part at the electrode tip is used. May not be able to accurately determine the polishing state. Therefore, there is room for improvement in accurately determining the polished state of the electrode tip.

JP 2002-273575 A

  The present invention has been conceived under the circumstances described above, and provides a spot welding electrode pass / fail judgment device suitable for more accurately judging the quality of a polished state of an electrode tip. Let it be the main issue.

  In order to solve the above problems, the present invention employs the following technical means.

  The spot-welding electrode pass / fail determination apparatus provided by the first aspect of the present invention includes an energization medium that contacts the tips of a pair of electrodes, and the energization during energization of the energization medium via the pair of electrodes. A measurement unit that measures a measurement value related to the medium, and a determination unit that determines the quality of the polishing state of the pair of electrodes based on the measurement value related to the current-carrying medium measured by the measurement unit.

  The spot welding electrode pass / fail determination apparatus provided by the second aspect of the present invention includes an energization medium that contacts the tips of a pair of electrodes, and the energization during energization of the energization medium via the pair of electrodes. It is characterized by comprising a measuring unit for measuring the calorific value of the medium, and a determining unit for judging the quality of the polishing state of the pair of electrodes based on the calorific value of the energized medium measured by the measuring unit.

  The spot welding electrode pass / fail judgment device provided by the third aspect of the present invention includes an energization medium that abuts the tip of a pair of electrodes, and the energization during energization of the energization medium via the pair of electrodes. A measuring unit that measures the resistance value of the medium, and a determination unit that determines the quality of the polishing state of the pair of electrodes based on the resistance value of the current-carrying medium measured by the measuring unit.

  The spot welding electrode pass / fail determination apparatus provided by the fourth aspect of the present invention includes an energization medium that contacts the tips of a pair of electrodes, and the energization during energization of the energization medium via the pair of electrodes. A measurement unit that measures the resistance value of the medium, and a determination unit that determines whether the polishing state of the pair of electrodes is good or not based on the resistance value of the current-carrying medium measured by the measurement unit. It is a cutter for cutting and polishing the tip of the pair of electrodes mounted on a polishing apparatus.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a schematic block diagram which shows an example of the quality determination apparatus of the electrode for spot welding which concerns on this invention. It is a schematic block diagram which shows the other example of the quality determination apparatus of the electrode for spot welding which concerns on this invention. The modification of the quality determination apparatus shown in FIG. 2 is shown. It is a schematic block diagram which shows the further another example of the quality determination apparatus of the electrode for spot welding which concerns on this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an example of a quality determination device for spot welding electrodes according to the present invention. As shown in FIG. 1, the quality determination device A1 of the present embodiment includes a support 1, a current-carrying medium 2, a calorific value measurement unit 3A, and a determination unit 4, and is in a polished state of the spot welding electrode. It is to judge pass / fail. The support 1 supports the energization medium 2 and is made of a material having electrical insulation. A through hole 11 is formed in the support 1 so as to penetrate in the thickness direction. The energizing medium 2 is fitted and fixed in the through hole 11 of the support 1. The energization medium 2 is made of a conductive metal material and has a predetermined resistivity. The upper surface 21 and the lower surface 22 of the current-carrying medium 2 and the surface portion surrounding them in the support 1 are concave curved surfaces, and the concave curved surfaces correspond to the tip shape of the spot welding electrodes (a pair of electrodes 6 and 6). Shape. The diameter D1 of the upper surface 21 and the lower surface 22 is, for example, about Φ8 mm.

  The pair of electrodes 6 and 6 have a substantially cylindrical shape at the main part and a tapered surface at the tip part. The pair of electrodes 6 and 6 have their tips worn by repeated welding operations and change in shape, but are polished to have a desired shape using a polishing apparatus (not shown). The polishing apparatus includes a cutter having a shape corresponding to the tip shape of the pair of electrodes 6 and 6. The polishing operation of the electrodes 6 and 6 is performed by rotating the cutter while pressing the cutter between the pair of electrodes 6 and 6. The concave curved surfaces (the upper surface 21 and the lower surface 22 of the current-carrying medium 2) match the tip shapes of the electrodes 6 and 6 that have a desired shape after polishing.

  The calorific value measuring unit 3 </ b> A measures the amount of heat generated when the energization medium 2 is energized. As this calorie | heat amount measurement part 3A, the well-known calorimeter comprised using the temperature sensor etc. can be used.

  The determination unit 4 determines the quality of the polished state of the tip of the electrode 6 based on the calorific value measured by the calorie measuring unit 3A.

  The determination of the quality of the electrode tip by the determination unit 4 is performed based on, for example, control by a control panel (not shown). The control panel performs drive control of a welding robot (not shown) equipped with a pair of electrodes. The control panel also performs drive control of the polishing apparatus. For example, during a welding operation, control signals are output from the control panel to the welding robot, and detection signals from various sensors are input to the control panel. Further, during the polishing operation, various detection signals are input to the control panel while a control signal is output from the control panel to the welding robot and the polishing apparatus.

  When determining the quality of the electrode tip in the determination unit 4, first, the energized medium 2 is positioned by the electrodes 6, 6 while aligning the pair of polished electrodes 6, 6 with the upper surface 21 and the lower surface 22 of the energized medium 2. Between. Next, a predetermined current is passed through the energizing medium 2 through the pair of electrodes 6 and 6 with the tips of the electrodes 6 and 6 being in contact with the upper surface 21 and the lower surface 22. Then, the calorific value of the energizing medium 2 is measured by the calorie measuring unit 3A. Here, when the tips of the electrodes 6 and 6 are finished in a desired shape, the tips of the electrodes 6 and 6 come into contact with the entire upper surface 21 and lower surface 22 of the energization medium 2. In this case, the calorific value measured by the calorie measuring unit 3A does not exceed a predetermined threshold value, and the determination unit 4 determines that the polished state of the tips of the electrodes 6 and 6 is good.

  On the other hand, when the tips of the electrodes 6 and 6 after polishing are not finished in a desired shape, the tips of the electrodes 6 partially abut against the upper surface 21 and the lower surface 22 of the current-carrying medium 2, and against the upper surface 21 and the lower surface 22. As a result, a portion where the tip of the electrode 6 does not contact is generated. In this case, the amount of heat generated by the energization medium 2 is increased as compared with the case where the tips of the electrodes 6 and 6 are in contact with the entire upper surface 21 and lower surface 22. And when the said emitted-heat amount exceeds a predetermined threshold value, the determination part 4 determines with the grinding | polishing state of the front-end | tip of the electrodes 6 and 6 being bad. The calorific value of the energizing medium 2 measured by the calorie measuring unit 3A is an example of the “measured value relating to the energizing medium when energizing the energizing medium via the pair of electrodes” in the present invention.

  Next, the operation of this embodiment will be described.

  In the spot-welding electrode quality determination apparatus A1 of the present embodiment, the current-carrying medium 2 that contacts the tips of the pair of electrodes 6 and 6 is energized through the electrodes 6 and 6, and the amount of heat generated by the current-carrying medium 2 at that time is increased. Based on this, the quality of the polished state of the tips of the electrodes 6 and 6 is determined. According to such a configuration, whether or not the curved surface shape in a predetermined range at the tips of the electrodes 6 and 6 has been restored to a desired shape is based on the amount of reflected light at the center of the tip of the electrode described in Patent Document 1, for example. Compared with the determination method, it is possible to determine directly and accurately. As a result, it is possible to maintain welding quality after electrode polishing.

  2-4 has shown the other example of the quality determination apparatus of the electrode for spot welding which concerns on this invention. In these drawings, the same or similar elements as those in the above embodiment are denoted by the same reference numerals as those in the above embodiment, and description thereof will be omitted as appropriate.

  The pass / fail determination device A2 shown in FIG. 2 includes a support 1, a current-carrying medium 2, a resistance value measurement unit 3B, and a determination unit 4. In the present embodiment, the configurations of the support 1 and the current-carrying medium 2 are substantially the same as those in the above-described embodiment, but are significantly different from the above-described embodiment in that a resistance value measuring unit 3B is provided instead of the calorific value measuring unit 3A.

  The resistance value measuring unit 3 </ b> B measures a resistance value when the energization medium 2 is energized. A known resistance meter or the like can be used as the resistance value measuring unit 3B. In the present embodiment, when determining the quality of the electrode tip, the pair of terminal portions 7 and 7 for connecting the pair of electrodes 6 and 6 and the resistance value measuring unit 3B are brought into contact with the electrodes 6 and 6.

  When determining the quality of the electrode tip in the determination unit 4, first, the energized medium 2 is positioned by the electrodes 6, 6 while aligning the pair of polished electrodes 6, 6 with the upper surface 21 and the lower surface 22 of the energized medium 2. Between. Next, a predetermined current / voltage is supplied to the energization medium 2 through the pair of electrodes 6 and 6 with the tips of the electrodes 6 and 6 being in contact with the upper surface 21 and the lower surface 22. Then, the resistance value of the energizing medium 2 is measured by the resistance value measuring unit 3B. Here, when the tips of the electrodes 6 and 6 are finished in a desired shape, the tips of the electrodes 6 and 6 come into contact with the entire upper surface 21 and lower surface 22 of the energization medium 2. In this case, the resistance value measured by the resistance value measurement unit 3B does not exceed the predetermined threshold value, and the determination unit 4 determines that the polished state of the tips of the electrodes 6 and 6 is good.

  On the other hand, when the tips of the electrodes 6 and 6 after polishing are not finished in a desired shape, the tips of the electrodes 6 partially abut against the upper surface 21 and the lower surface 22 of the current-carrying medium 2, and against the upper surface 21 and the lower surface 22. As a result, a portion where the tip of the electrode 6 does not contact is generated. In this case, the resistance value of the current-carrying medium 2 to be measured increases as compared with the case where the tips of the electrodes 6 and 6 are in contact with the entire upper surface 21 and lower surface 22. And when the said resistance value exceeds a predetermined threshold value, the determination part 4 determines with the grinding | polishing state of the front-end | tip of the electrodes 6 and 6 being unsatisfactory. The resistance value of the energizing medium 2 measured by the resistance value measuring unit 3B is an example of the “measured value related to the energizing medium when energizing the energizing medium via the pair of electrodes” in the present invention.

  Next, the operation of this embodiment will be described.

  In the spot welding electrode quality determination device A2 of this embodiment, the current-carrying medium 2 contacting the tips of the pair of electrodes 6 and 6 is energized through the electrodes 6 and 6, and the resistance value of the current-carrying medium 2 at that time is set. Based on this, the quality of the polished state of the tips of the electrodes 6 and 6 is determined. According to such a configuration, whether or not the curved surface shape in a predetermined range at the tips of the electrodes 6 and 6 has been restored to a desired shape is based on the amount of reflected light at the center of the tip of the electrode described in Patent Document 1, for example. Compared with the determination method, it is possible to determine directly and accurately. As a result, it is possible to maintain welding quality after electrode polishing.

  FIG. 3 shows a modification of the quality determination apparatus shown in FIG. 3 includes a pair of resistance measurement units 3B and 3B, each corresponding to a pair of electrodes 6 and 6, respectively. In the present modification, the resistance value measuring units 3 </ b> B and 3 </ b> B are individually connected to the energizing medium 2 via the terminal units 8. When determining the quality of the electrode tip, a terminal portion 7 for connecting the electrode 6 and the corresponding resistance value measuring unit 3B is brought into contact with each electrode 6.

  According to the pass / fail judgment device A2 ′ shown in FIG. 3, as in the pass / fail judgment device A2, whether or not the curved surface shape of a predetermined range at the tips of the electrodes 6 and 6 is restored to a desired shape is directly determined. And it is possible to judge accurately. Furthermore, according to the configuration of the quality determination device A2 ′, since the pair of resistance measurement units 3B and 3B corresponding to the pair of electrodes 6 and 6 are provided, the quality of the polishing state of each of the pair of electrodes 6 and 6 is determined. Can be determined simultaneously and individually.

  The quality determination apparatus A3 shown in FIG. 4 is incorporated in the polishing apparatus, and is greatly different from the configuration of the above embodiment in this respect. The polishing apparatus includes a cutter holder 9 rotatably supported by a gear case (not shown), and a cutter 91 attached to the cutter holder 9. The cutter holder 9 has a pair of recesses 9a into which the tip portions of the pair of electrodes 6 and 6 can be fitted. One of the pair of recesses 9 a faces upward and the other faces downward, and each has a concave curved surface shape corresponding to the tip of the electrode 6. The cutter holder 9 is made of a material having electrical insulation, for example.

  The cutter 91 is for cutting and polishing the tip of the electrode 6, and has a substantially arcuate blade portion 91 a corresponding to the tip shape of the electrode 6. The blade portion 91a slightly protrudes from the surface of the recessed portion 9a. The cutter 91 is made of a conductive metal material and has a predetermined resistivity.

  The quality determination device A3 of the present embodiment includes a cutter 91, a resistance value measurement unit 3B, and a determination unit 4. In the present embodiment, when determining the quality of the electrode tip, the pair of terminal portions 7 and 7 for connecting the pair of electrodes 6 and 6 and the resistance value measuring unit 3B are brought into contact with the electrodes 6 and 6.

  In this embodiment, the quality of the electrode tip is determined immediately after the polishing is completed, for example. While the cutter 91 is sandwiched between the pair of electrodes 6, 6, a predetermined current / voltage is supplied to the cutter 91 via the electrodes 6, 6 while rotating the cutter 91 (cutter holder 9) at a predetermined rotational speed. Based on the resistance value of the cutter 91 at that time, the quality of the polished state of the tips of the electrodes 6 and 6 is determined. Here, when the tips of the electrodes 6 and 6 are finished in a desired shape, the tips of the electrodes 6 and 6 come into contact with the entire predetermined range of the cutter 91. In this case, the resistance value measured by the resistance value measurement unit 3B does not exceed the predetermined threshold value, and the determination unit 4 determines that the polished state of the tips of the electrodes 6 and 6 is good.

  On the other hand, when the tips of the electrodes 6 and 6 after polishing are not finished in a desired shape, the tip of the electrode 6 partially contacts the predetermined range of the cutter 91, and the tip of the electrode 6 is in contact with the predetermined range. The part which does not contact arises. In this case, the measured resistance value of the cutter 91 is increased as compared with the case where the tips of the electrodes 6 and 6 are in contact with the entire predetermined range of the cutter 91. And when the said resistance value exceeds a predetermined threshold value, the determination part 4 determines with the grinding | polishing state of the front-end | tip of the electrodes 6 and 6 being unsatisfactory. In addition, the cutter 91 of this embodiment is corresponded to the electricity supply medium said by this invention.

  According to the quality determination device A3 of the present embodiment, it is possible to determine directly and accurately whether or not the curved surface shape in a predetermined range at the tips of the electrodes 6 and 6 is restored to a desired shape. In addition, according to the present embodiment, it is possible to determine whether the polishing state of the electrodes 6 and 6 is good or not immediately after the polishing operation is performed on the tips of the pair of electrodes 6 and 6. Therefore, it is possible to greatly reduce the work time related to the quality determination of the electrodes 6 and 6. Further, when it is determined that the polished state of the tips of the electrodes 6 and 6 is poor, the polishing operation of the electrodes 6 and 6 can be continued, which contributes to shortening of the working time at the time of re-polishing.

  Although the embodiment of the present invention has been described above, the technical scope of the present invention is not limited to the above-described embodiment. The specific configuration of each part of the present invention can be variously changed.

A1, A2, A2 ', A3 Pass / fail judgment device 1 Support body 11 Through hole 2 Conducting medium 21 Upper surface 22 Lower surface 3A Calorific value measurement unit (measurement unit)
3B Resistance measurement unit (measurement unit)
4 Judgment part 6 Electrode 7 Terminal part 8 Terminal part 9 Cutter holder 9a Recessed part 91 Cutter (energization medium)
91a Blade

Claims (4)

An apparatus for determining whether the state of polishing of the tip of the electrode for spot welding is good or bad,
A current-carrying medium that abuts the tip of a pair of electrodes, a measurement unit that measures a measurement value related to the current-carrying medium when energizing the current-carrying medium through the pair of electrodes, and a current-carrying medium that is measured by the measurement unit A determination unit for determining whether or not the polishing state of the pair of electrodes is good based on a measurement value. An apparatus for determining whether the state of polishing of the tip of the electrode for spot welding is good or bad,
A current-carrying medium that abuts the tip of a pair of electrodes, a measurement unit that measures the amount of heat generated by the current-carrying medium when the current-carrying medium is energized via the pair of electrodes, and the current-carrying medium measured by the measurement unit. And a determination unit for determining whether the polishing state of the pair of electrodes is good or not based on a calorific value. An apparatus for determining whether the state of polishing of the tip of the electrode for spot welding is good or bad,
A current-carrying medium that contacts the tips of the pair of electrodes, a measurement unit that measures the resistance value of the current-carrying medium when the current-carrying medium is energized via the pair of electrodes, and the current-carrying medium measured by the measurement unit. And a determination unit for determining whether the polishing state of the pair of electrodes is good or not based on a resistance value. An apparatus for determining whether the state of polishing of the tip of the electrode for spot welding is good or bad,
A current-carrying medium that contacts the tips of the pair of electrodes, a measurement unit that measures the resistance value of the current-carrying medium when the current-carrying medium is energized via the pair of electrodes, and the current-carrying medium measured by the measurement unit. A determination unit that determines the quality of the polishing state of the pair of electrodes based on a resistance value, and
The quality determination device for a spot welding electrode, wherein the energization medium is a cutter for cutting and polishing the tips of the pair of electrodes mounted on a polishing apparatus.

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