JP2002273575A - Polishing quality inspecting device for spot welding electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect polishing quality at an electrode tip end with high precision. SOLUTION: In a polishing quality inspecting device A for a spot welding electrode, the center of the tip end surface of the electrode 1 exposing from an inspecting hole 13 which is formed in the seat part 11 of a positioning housing 3 is irradiated by inspecting light beams 21 from a light emitting part 17, and the inspecting light beams 21 reflected by the center of the tip end surface of the electrode 1 are received by a light receiving part 18. A light quantity of the inspecting light beams 21 received by the light receiving part 18 is measured, for example, as a reflected light quantity by being converted into current with a receiving element. 'Polishing is not satisfactory' is judged when the reflected light quantity of measured inspecting light beams 21 is smaller than a prescribed value, while 'polishing is excellent' is judged when it is larger than the value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting the quality of polishing of a spot welding electrode for detecting whether or not the polishing state of the tip of the spot welding electrode is good and for preventing a defective welding.

[0002]

2. Description of the Related Art As a spot welding electrode is continuously used in a welding operation, its tip is partially worn to form a flat portion, and this flat portion gradually expands. If the welding operation is continued in such a state, the current density is reduced and a predetermined Joule heat cannot be obtained, resulting in poor welding. For this reason, in the spot welding work, the tip end curved surface of the electrode is periodically polished so as to return to a predetermined curvature.

[0003] For polishing the electrode, for example, using a polishing apparatus provided with a polishing blade in the hollow of the rotating mortar-shaped member, the mortar with the tip of the spot welding electrode pressed against the dent of the mortar-shaped member. The electrode is polished by rotating the shaped member.

[0004] By the way, the oxide of the work adheres to the tip of the electrode before polishing in a black scale state. Conventionally, the quality of the polished state is determined by whether or not the black scale is removed. I was checking it visually. However, it is too expensive for an operator to judge the quality of the polishing every time the polishing is performed regularly, and the judgment of the quality is likely to vary due to the visual inspection.

Therefore, there has been proposed an apparatus for automatically determining whether the polishing state of the electrode tip is good or not. For example, Japanese Unexamined Utility Model Publication No. 5-24175 discloses an electrode 54 as shown in FIG.
Mortar-shaped seating part 51 corresponding to the shape of the tip, and seating part 51
A guide member 53 having a hole 52 through which the tip of the polished electrode 54 can be inserted so that the tip of the electrode 54 can be protruded into the center of the electrode 54, and seated with the tip of the electrode 54 seated on the seating portion 51 Apparatus 50 for detecting the suitability of the amount of protrusion of the tip of the electrode 54 from the center hole 52 of the part 51 with the limit switch 55 and inspecting the quality of the polished state of the tip of the electrode 54 is described. I have.

This apparatus utilizes the fact that if the polished state of the tip of the electrode 54 after polishing is good, the tip has a specified curvature. That is, if the polishing state is good, as shown in FIG. 7, the tip of the electrode 54 protrudes from the center hole 52 of the seating portion 51 by a predetermined protrusion amount d1 and presses the limit switch 55. Is good. " On the other hand, if the polishing state is insufficient, FIG.
As shown in (5), since the protrusion amount d2 does not reach the specified protrusion amount d1, the limit switch 55 does not operate, and it is determined that "polishing is insufficient".

[0007]

The above inspection apparatus does not directly judge the quality of polishing of the tip end surface of the electrode itself, but determines whether the electrode 54 passes through the hole 52 of the seating portion 51 of the guide member 53.
Is only indirectly determined by the amount by which the tip of. Therefore, for example, even when the tip of the electrode 54 is not sufficiently polished, if foreign matter is attached to the tip of the electrode 54, the tip protrudes more than the specified protrusion amount d1 in the inspection, and `` the polishing state is good. May be incorrectly determined to be.

Further, as shown in FIG. 9, the change (Δd) in the protrusion amount is very small with respect to the change amount (s2-s1) in the area of the unpolished portion remaining at the tip of the electrode 54. The inspection accuracy is not necessarily higher than the method of visually inspecting the area of the unpolished portion, that is, the black scale residue.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for inspecting the quality of polishing with higher accuracy without the risk of erroneous determination.

[0010]

According to a first aspect of the present invention, there is provided an apparatus for inspecting the polishing quality of an electrode for spot welding, comprising: a light emitting section for irradiating the center of the front end surface of the polished spot welding electrode; A light receiving unit for receiving the reflected light from the light receiving unit, a measuring unit for measuring the amount of reflected light received by the light receiving unit, and detecting whether the polishing state of the electrode tip surface is good or not based on the amount of reflected light measured by the measuring unit. And a high-precision polishing quality determination by directly inspecting the electrode tip surface.

According to a second aspect of the present invention, there is provided an apparatus for inspecting polishing quality of a spot welding electrode, wherein a reference reflection member having a predetermined reflection characteristic for reflecting light emitted from a light emitting portion to a light receiving portion is provided separately from the spot welding electrode. And an abnormality in the light emitting unit, the light receiving unit or the measuring unit is detected based on the amount of reflected light from the reference reflecting member measured by the measuring unit. Thus, since the abnormality of the light emitting unit, the light receiving unit, and the measuring unit can be detected in advance, it is possible to prevent an erroneous determination as to whether the polishing is good or bad.

According to a third aspect of the present invention, there is provided an apparatus for inspecting the polishing quality of a spot welding electrode, wherein a reference reflection member having a predetermined reflection characteristic for reflecting light emitted from a light emitting portion to a light receiving portion is provided separately from the spot welding electrode. And a threshold for detecting whether the polishing state of the electrode tip surface is good or not based on the amount of reflected light from the reference reflecting member measured by the measuring unit. This makes it possible to automatically reset the threshold value corresponding to the deterioration with time of the light emitting unit and the light receiving unit, to extend the service life of the light emitting unit and the light receiving unit, and to prevent erroneous detection due to inappropriate setting of the threshold value. .

According to a fourth aspect of the present invention, there is provided an apparatus for inspecting the polishing quality of a spot welding electrode, wherein a mortar-shaped seating portion is formed on an outer surface of the electrode for abutting a tip end surface of the spot welding electrode for positioning. A hollow positioning jig having an inspection hole formed at the center of the hole, an air nozzle for supplying compressed air to the space in the positioning jig, and an electrode tip surface disposed inside the positioning jig and exposed from the inspection hole. A light-emitting unit for irradiating the center, a light-receiving unit disposed inside the positioning jig and receiving reflected light from the center of the electrode tip surface, a measuring unit for measuring the amount of reflected light received by the light-receiving unit, and a measurement unit Polishing quality detection means for detecting the quality of the polishing state of the electrode tip surface based on the amount of reflected light measured by the section. This makes it possible to remove foreign substances that have unexpectedly adhered to the seating section, the light emitting section, the light receiving section, etc. by the wind pressure of the compressed air ejected from the air nozzle, thereby improving the reliability of the inspection.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus for inspecting the quality of polishing of a spot welding electrode according to an embodiment of the present invention will be described below with reference to the drawings.

Inspection device A for polishing quality of electrode for spot welding
As shown in FIG. 1, a positioning housing 3 as a hollow positioning jig, an optical sensor unit 4 for inspecting the quality of electrode polishing, an actuator 5, and an air nozzle 6 for supplying compressed air to the inside of the positioning housing 3 , A compressor 7, a measurement unit 8, and a polishing quality detection unit 9. This polishing quality inspection apparatus A is used for a spot welding apparatus that performs spot welding while a work is sandwiched between a pair of electrodes 1 and 2, and inspects two polishing states of the tips of the electrodes 1 and 2 simultaneously.

The positioning housing 3 is cylindrical and has a mortar-shaped seating portion 11 for positioning by bringing the tip end surfaces of the electrodes 1 and 2 into contact with the outer side surfaces of the opposing side walls in the middle portion in the longitudinal direction.
2 is formed in a coaxially aligned state. In the center of the seats 11, 12, an inspection hole 13, which penetrates into the positioning housing 3,
14 are formed. In the positioning housing 3, a support 16 of the optical sensor unit 4 is accommodated slightly away from the seating portions 11 and 12, and an air nozzle is provided on the opposite end wall of the positioning housing 3 so as to face the support 16. 6 is attached.

The optical sensor unit 4 includes a support 16 and inspection units 19 and 20 having a light emitting unit 17 and a light receiving unit 18 attached to one end of the support 16. The support 16 is reciprocated back and forth inside the positioning housing 3 by the actuator 5 in a state where airtightness is secured between the support 16 and the inner surface of the positioning housing 3.

As shown in FIGS. 2A and 2B, the two inspection sections 19 and 20 extend from the support 16 in the direction of the air nozzle 6 in parallel with each other. The inspection units 19 and 20 are provided with a light emitting unit 17 that emits an inspection light beam 21 and a light receiving unit 18 that receives reflected light of the inspection light beam 21 toward the inspection holes 13 and 14. The light emitting unit 17 and the light receiving unit 18 are connected to the light source and the measuring unit 8 via an optical fiber cable (not shown). Light emitting unit 17
As shown in FIGS. 2A and 2B, a light shielding plate 22
The light emitted from the light emitting unit 17 is directly
To prevent light from entering The inspection unit 20 is an inspection unit
Since it has a vertically symmetric structure with 19, illustration and description are omitted.

As shown in FIG. 2 (b), the light emitting section 17 is a seating section.
The inspection light beam 21 is provided so as to irradiate the center of the distal end surfaces of the electrodes 1 and 2 exposed from the inspection holes 13 and 14 of 11 and 12. The light receiving section 18 is provided so as to receive the inspection light beam 21 reflected at the center of the distal end surfaces of the electrodes 1 and 2. The inspection light beam 21 received by the light receiving unit 18 passes through the optical fiber cable and is
The light receiving element in 8 converts the current into a current proportional to the amount of light. Then, based on the current value, the light amount of the inspection light beam 21 received by the light receiving unit 18 is measured by the measuring unit 8, and the polishing quality detection unit 9 determines whether the polishing state of the electrode is good or not based on the amount of light measured by the measuring unit 8. No is detected. The specific mode of the polishing quality detector 9 will be described later.

The actuator 5 moves the support 16 of the optical sensor unit 4 between a forward position shown in FIG. 1 and a retracted position shown in FIG. 3, and includes, for example, an air cylinder 26 fixed to a base 25. Is done. The tip of the piston rod 27 of the air cylinder 26 is
It is attached to. A compressor 7 is connected to the air nozzle 6, and the compressed air from the compressor 7 is blown toward the internal space of the positioning housing 3.

Inspection device A for polishing quality of electrode for spot welding
Is configured as described above, and the polishing quality inspection using the apparatus A is performed as follows. First, the air cylinder 26 is shortened to return the optical sensor unit 4 to the retracted position in FIG. In this state, the tips of the electrodes 1 and 2 polished in the polishing step are directly opposed to the seats 11 and 12. Next, compressed air is ejected from the air nozzle 6 and the compressed air is injected into the inspection hole 1.
Spout vigorously to the outside from 3,14. Due to the strong wind pressure at this time, the inspection sections 19 and 20, the seating sections 11 and 12, and the electrodes 1 and 2,
Foreign matter that has unexpectedly adhered to the tip of 2 can be completely removed.

Next, a spot welding apparatus (not shown) is operated to bring the tips of the electrodes 1 and 2 into contact with the seating portion 11 of the positioning housing.
Sit on 12. At this time, since the seating portions 11 and 12 are formed in a mortar shape, when the tips of the electrodes 1 and 2 fit into the seating portions 11 and 12, the centers of the tip surfaces of the electrodes 1 and 2 are seated portions 11 and 12. Inspection hole 1
Fits to match the center of 3,14. This allows electrode 1,
The center of the tip surface of the second can be accurately aligned with the center of the inspection holes 13 and 14 of the seating portions 11 and 12. At this time, as shown in FIG. 3, the inspection sections 19 and 20 of the optical sensor unit 4 are still in the inspection hole.
Since the electrodes 13 and 14 are not close to each other, there is no possibility that the minute foreign matter separated from the electrodes 1 and 2 adheres to the inspection units 19 and 20 due to the impact when the electrodes 1 and 2 are seated.

Next, as shown in FIG. 1, the air cylinder 26 is extended, and the inspection sections 19 and 20 of the optical sensor unit 4 are inserted into the inspection holes 1.
Move to just below or directly above 3,14. Optical sensor unit
As shown in FIGS. 2A and 2B, the inspection units 19 and 20 of FIG.
Irradiates the inspection light beam 21 from the center of the tip surfaces of the electrodes 1 and 2
The inspection light beam 21 reflected at the center of the front end surface of the light receiving section 18 is received by the light receiving section 18.

The inspection light beam 21 received by the light receiving section 18 is applied to a light receiving element of the measuring section 8 through an optical fiber cable (not shown). The light receiving element generates a current having an intensity proportional to the amount of reflected light of the inspection light beam 21, and the measuring section 8 converts this current value into a voltage to measure the amount of reflected light.

At this time, if the polishing of the electrodes 1 and 2 is not sufficient, FIG.
As shown in (a), the oxide 28 of the workpiece remains in the center of the tip surfaces of the electrodes 1 and 2 in a black-skin state, so that the amount of reflected light of the inspection light beam 21 decreases. On the other hand, when the electrodes 1 and 2 are sufficiently polished, as shown in FIG. 4 (b), since the electrode base 29 is exposed at the center of the tip end surfaces of the electrodes 1 and 2, the inspection beam The reflected light quantity of 21 increases. There is a difference of about 2 to 16 times in the amount of reflected light of the inspection light beam 21 between the case where the oxide 28 of the work remains and the case where the electrode substrate 29 is exposed. It can be said that the size is sufficient to accurately detect the quality.

The polishing quality detector 9 desirably informs the worker of the suitability of the reflected light amount measured by the measuring unit 8 by blinking a lamp or a warning sound in an easy-to-understand manner. It may be provided with a display unit for displaying in an analog manner. If the polishing quality detector 9 determines that “polishing is insufficient”, the electrodes 1 and 2 are polished again and then inspected again.

Next, a polishing quality inspection apparatus A 'according to a modification of the present invention will be described with reference to FIG. In this modification, the reference reflecting members 30 and 31 are arranged on the inner side surface of the positioning housing 3, and particularly detect a decrease in the output voltage due to the deterioration with time of the light receiving element of the measuring section 8. In other words, if the inspection is repeated without replacing the light receiving element, even if the polishing state is good and the electrode base is exposed at the center of the tip end surfaces of the electrodes 1 and 2, the reflected light amount of the inspection light beam 21 can be measured by the light receiving element. When the current is converted into a current, the output voltage becomes lower than the reference threshold, and the polishing quality detection unit 9 may erroneously determine that “polishing is insufficient”.

Therefore, as shown in FIG.
The inspection unit 19 of the optical sensor unit 4,
Reference reflection members 30, 3 made of a material having a predetermined reflection characteristic on the inner surface of the positioning housing 3 so as to face the reference reflection member 20.
1 was placed. The amount of reflected light of the inspection light beam 21 that is reflected when the inspection light beam 21 is applied to the reference reflecting members 30 and 31 is measured in advance while the light receiving element is new.

The amount of reflected light of the inspection light beam 21 from the reference reflecting members 30 and 31 is substantially constant because it is determined by the reflection characteristics of the reference reflecting members 30 and 31. Therefore, the light emitting unit 17 and the light receiving unit 18
If the measuring unit 8 is normal, the amount of reflected light from the reference reflecting members 30, 31 is always measured by the measuring unit 8 as a value within a certain range.

On the other hand, when the light amount of the inspection light beam 21 output from the light emitting element is reduced, or when the output voltage of the light receiving element is reduced, the light emitting unit 17, the light receiving unit 18, or the measuring unit 8 is used. If any one of them has an abnormality, the measurement value of the measurement unit 8 deviates from the normal range. From this, it is possible to early detect that there is some abnormality in the polishing quality detector 9. When the abnormality is found, the light emitting unit 17,
Maintenance of the light receiving unit 18 and the measuring unit 8 will be performed. If the abnormality is caused by mere deterioration of the light receiving element with time, the reflected light amount of the inspection light beam 21 obtained by the meter side unit 8 is set as a new reference Alternatively, the threshold for determining the quality of polishing may be reset. As described above, by adding a configuration for detecting an abnormality of the light emitting unit 17, the light receiving unit 18, or the measuring unit 8, erroneous detection of polishing quality can be prevented.

As described above, the embodiment and the modification of the apparatus A for inspecting the quality of the polishing of the electrode for spot welding according to the present invention have been described, but the present invention is not limited to these. For example, the above embodiment is configured to be compatible with a spot welding apparatus having a pair of electrodes 1 and 2 facing each other.However, the configuration of the positioning housing 3 and the like according to the type of the spot welding apparatus or the arrangement of the electrodes are different. It can be changed as appropriate, and if either one of the inspection parts 19 or 20 can be accurately positioned and fixed to one electrode with an appropriate jig, a small, lightweight and handy type inspection apparatus that does not use the positioning housing 3 etc. Can also be configured.

[0032]

The apparatus for inspecting the quality of polishing of a spot welding electrode according to the first aspect detects the quality of polishing by directly measuring the amount of light reflected from the center of the tip end surface of the spot welding electrode, thereby achieving high precision. Polishing quality determination processing can be performed.

According to a second aspect of the present invention, there is provided an apparatus for inspecting the quality of polishing of a spot welding electrode, wherein a reference reflection member having a predetermined reflection characteristic is formed so as to reflect light emitted from a light emitting portion to a light receiving portion. Since it is provided at a different position, it is possible to detect an abnormality in the light emitting unit, the light receiving unit or the measuring unit based on the amount of reflected light from the reference reflecting member measured by the measuring unit, thereby preventing erroneous determination of polishing quality.

According to a third aspect of the present invention, there is provided an apparatus for inspecting the quality of polishing of a spot welding electrode based on the amount of reflected light from a reference reflecting member measured by a measuring unit. Since the threshold value is set, erroneous detection of polishing quality can be prevented, and the accuracy of polishing quality detection can be maintained at a high level by resetting the threshold value before the inspection of polishing quality.

According to a fourth aspect of the present invention, there is provided an apparatus for inspecting the quality of polishing of a spot welding electrode, which removes foreign matters adhering to a seating portion, a light emitting portion, a light receiving portion, and an electrode surface by wind pressure of compressed air ejected from an air nozzle. Therefore, erroneous determination due to foreign matter can be prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal side view of a polishing quality inspection apparatus for a spot welding electrode according to an embodiment of the present invention.

FIG. 2A is a partial cross-sectional view showing an inspection unit of a polishing quality inspection apparatus for spot welding electrodes according to an embodiment of the present invention, and FIG. 2B is an aa cross-sectional view thereof.

FIG. 3 is a vertical sectional side view of a polishing quality inspection apparatus for a spot welding electrode according to an embodiment of the present invention.

FIG. 4 is a front view of an electrode.

FIG. 5 is a vertical sectional side view of a polishing quality inspection apparatus for a spot welding electrode according to a modification of the present invention.

FIG. 6 is a perspective view showing a conventional polishing quality inspection apparatus.

FIG. 7 is a sectional view showing an inspection state of a conventional polishing quality inspection apparatus.

FIG. 8 is a sectional view showing an inspection state of a conventional polishing quality inspection apparatus.

FIG. 9 is a sectional view showing an inspection state of a conventional polishing quality inspection apparatus.

[Explanation of symbols]

 A Polishing quality inspection device 1, 2 Spot welding electrode 3 Positioning housing 4 Optical sensor unit 5 Actuator 6 Air nozzle 7 Compressor 8 Measuring unit 9 Polishing quality detection unit 11, 12 Seating portion 13, 14 Inspection hole 16 Support 17 Light emitting unit 18 Light receiving unit 19, 20 Inspection unit 21 Inspection beam 22 Light shielding plate 25 Base 26 Air cylinder 27 Piston rod 28 Fused piece of material 29 Base material of electrode 30, 31 Reference reflection member

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Hideyo Takeuchi 2-1-1, Taoyuan, Ikeda-shi, Osaka Daihatsu Industry Co., Ltd. (72) Kazuhiko Kuroshima 2-1-1 Taoyuan, Ikeda-shi, Osaka Daiha Within Katsu Kogyo Co., Ltd. (72) Koji Kanemitsu 2-1-1, Taoyuan, Ikeda-shi, Osaka Daihatsu Kogyo Co., Ltd. F-term (reference) 2F065 AA53 BB07 CC00 CC10 DD00 FF44 FF61 LL02 PP02 PP22 QQ08 SS04 SS09 SS12 SS15 TT02 TT03 TT04 UU02 UU03 UU05 2G051 AA90 AB20 BB17 CA01 CC17 EB01

Claims (4)

[Claims] 1. A light-emitting unit for irradiating the center of a tip end surface of a polished spot welding electrode, a light-receiving unit for receiving light reflected from the center of the electrode front-end surface, and measurement for measuring the amount of reflected light received by the light-receiving unit Unit, the amount of reflected light measured by the measuring unit
A polishing quality inspection apparatus for a spot welding electrode, comprising: a polishing quality detection means for detecting the quality of the polishing state of the electrode tip surface. 2. A polishing quality inspection apparatus according to claim 1, wherein a reference reflection member having a predetermined reflection characteristic for reflecting light emitted from the light emitting section to the light receiving section is provided at a position different from the spot welding electrode. An apparatus for inspecting polishing quality of a spot welding electrode, wherein an abnormality of the light emitting unit, the light receiving unit or the measuring unit is detected based on the amount of reflected light from the reference reflecting member measured by a measuring unit. 3. The polishing quality inspection apparatus according to claim 1, wherein a reference reflection member having a predetermined reflection characteristic for reflecting light emitted from the light emitting portion to the light receiving portion is provided at a position different from the spot welding electrode. Based on the amount of reflected light from the reference reflection member measured by the measuring unit, a threshold value for detecting whether the polishing state of the electrode tip surface is good or bad is set as a polishing quality of the electrode for spot welding. Inspection equipment. 4. A hollow positioning jig having a mortar-shaped seating portion for positioning by contacting a tip end surface of a spot welding electrode to an outer surface and having an inspection hole formed at the center of the seating portion. An air nozzle configured to supply compressed air to a space in the positioning jig; a light emitting unit disposed inside the positioning jig to irradiate a center of an electrode tip surface exposed from the inspection hole; A light receiving unit that is disposed inside the tool and receives reflected light from the center of the electrode tip surface; a measuring unit that measures the amount of reflected light received by the light receiving unit; An apparatus for inspecting the quality of polishing of a spot welding electrode, comprising: a polishing quality detecting means for detecting the quality of the polishing state of the electrode tip surface.