JP2000351083A - Method for inspecting tip end shape of spot welding electrode and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge the quality of the tip end shape of electrodes with a projecting quantity of the normal shape of the tip end of the electrodes by projecting the tip end of the electrodes into a space, whereby bringing the tip end of the electrodes into contact with a gage and detecting the normal shape of the tip ends of the electrodes. SOLUTION: Recessed parts 4, 5 coinciding with the shapes of electrodes 2, 3 are provided in a guide member 1, a space 7 is opened in the bottom parts of the recessed parts 4, 5, and the tip ends 9, 10 of the electrodes are brought into contact with the gage 8 inserted into the space 7 when the tip ends 9, 10 of the normal electrodes are projected into the space 7. Whereby, the quality of the electrodes is judged by imparting a limit to the movement of the gage 8 or detecting the length of the gage 8 based on the contact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION If the tip of a spot welding electrode becomes worn, a predetermined current density cannot be obtained, which impairs normal welding. Therefore, although the electrode tip is polished, it must be inspected whether the electrode tip is polished to a correct shape. The present invention belongs to the technical field of such inspection.

[0002]

2. Description of the Related Art Japanese Utility Model Application Laid-Open No. H5-24176 discloses an apparatus for inspecting a shape as described above. The technology disclosed here is to rotate the polishing cutter with an electric motor,
If the shape of the electrode pressed against this cutter is polished to a normal shape, the rotational load of the electric motor will increase, so this change will be grasped by the current value of the motor rotor, and this value will become a constant value. This indicates that the polishing has been completed when the time comes.

[0003]

According to the above-mentioned method, the contact resistance between the polishing cutter and the electrode changes due to the temperature condition of the contact sliding portion, the presence of some impurities, or the wear deformation of the polishing cutter. Therefore, it is difficult to detect a normal polishing shape with the current value of the motor rotor. In addition, it is performed to visually inspect the polishing state,
This requires sufficient skill and is not good in terms of inspection efficiency. In addition, inspection behavior is suitable for such an environment in an automatic welding line where robot devices are complicated,
Reliable inspections and results must be displayed.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems.
The basic idea is to open a space at the bottom of the guide member and let the gauge interfere with this protruding part when the electrode tip of a normal shape protrudes into the space to determine the quality of the electrode shape. I have.

According to the first aspect of the present invention, when the guide member is provided with a concave portion corresponding to the tip shape of the electrode, a space for inserting a gauge is formed at the bottom of the concave portion, and when the electrode having a normal shape is fitted into the concave portion. This is a method in which the normal shape of the electrode tip is detected by bringing the electrode tip into contact with the gauge by projecting the electrode tip into the space. Therefore, by the gauge interfering with the protruding part of the electrode,
The gauge is moved to indicate that it is normal, or the movement of the gauge is restricted and it is also displayed that it is normal. If the shape of the electrode tip is bad and the electrode tip does not contact the gauge,
Since the above-described gauge movement and the limitation of the gauge movement cannot be obtained, this state is detected to indicate that polishing is defective.

According to a second aspect of the present invention, in the first aspect, the concave portion is formed in a gutter shape, and the electrode is moved along the concave portion while the tip portion of the electrode is in contact with the gauge. In this method, the protruding state is detected to confirm that the tip of the electrode has a normal shape. Since the gauge is protruded from the guide member by the above-described movement, this protruding displacement is detected by a sensor to confirm that the gauge has a normal shape. If the shape of the electrode tip is not good, contact between the electrode tip and the gauge is not made, so the gauge remains stopped during the above-mentioned electrode movement, and this state is detected to indicate that polishing is poor. Is displayed.

According to a third aspect of the present invention, there is provided a method according to the first aspect, wherein the gauge inserted from the outside hits the electrode tip projecting into the space to confirm that the electrode tip has a normal shape. It is. Since the gauge is inserted from the outside and the tip of the gauge hits the protruding portion of the tip of the electrode, the insertion movement of the gauge is prohibited. In this state, it is confirmed that the polishing is good. If the polishing is poor, the gauge further advances without contacting the tip portion of the electrode. Therefore, the amount of advance is detected to confirm that the polishing is defective.

According to a fourth aspect of the present invention, there is provided an apparatus for implementing the method of the second aspect, wherein a gutter-shaped groove is provided on the guide member so as to conform to the shape of the electrode tip, and a bottom portion of the groove is provided. A space for inserting a bar-shaped gauge is formed along the longitudinal direction of the concave groove, and the guide member and the gauge are slidably supported by the guide rod, and the guide member and the gauge are independent from each other. It is configured so that it can slide. When the electrode tip slides inside the groove with the electrode tip fitted in the groove, the electrode tip is in contact with the gauge, so the gauge protrudes from the guide member and that part is detected by the sensor, and polishing is good. It is confirmed that. If the polishing is poor, the electrode tip does not contact the gauge, so the gauge does not protrude as described above.
It is confirmed that polishing is defective. The guide member and the gauge can slide independently of each other. Therefore, first, only the guide member is returned to the origin position, and the gauge is relatively protruded from the guide member.Then, the electrode is fitted into the groove, and the tip of the electrode is brought into contact with the gauge. When moved along, the gauge moves with the electrode movement and reaches the detection area of the sensor.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before entering into a specific embodiment, the principle of the present invention will be described with reference to FIGS. The guide member 1 is provided with concave portions 4 and 5 that match the tip shapes of the electrodes 2 and 3. The guide member 1 includes a stationary member 6
, And a space 7 is formed at the bottom of the recesses 4, 5. Since the electrodes 2 and 3 move forward and backward on the same axis, the concave portions 4 and 5 are also formed in a vertically symmetric state, and the space 7 is in a state of communicating with the bottom portions of both the concave portions 4 and 5. A gauge 8 is inserted into the space 7, which is an elongated rod-shaped member, and is supported by the stationary member 6 so as to be able to advance and retreat.

FIG. 3 is a longitudinal sectional front view showing an enlarged local portion.
The electrodes 2 and 3 shown in the figure are those whose shapes shown by solid lines are correctly polished. When such electrodes are matched with the concave portions 4 and 5, the electrode tips 9 and 10 project into the space 7 by the dimension L1.
In this state, the electrode tips 9 and 10 and the gauge 8 come into contact with each other. In order to do so, the width dimension of the space 7 in the left-right direction, the curved surface shape of the electrode tips 9, 10, and the gauge dimension L2 are selected. Therefore, when the normally polished electrodes 2 and 3 are matched with the recesses 4 and 5, the electrode tips 9 and 10 come into contact with the gauge 8. When such a contact is made, the electrode 2,
The dimensions of the components described above are set so that a slight gap is formed between the recess 3 and the recesses 4 and 5. Symbols 11 and 12
Indicates a shape when the amount of polishing at the electrode tip is insufficient, and a wide range of wear remains. Therefore, the portions 11 and 12 do not protrude into the space 7 and contact with the gauge 8 cannot be obtained.

When the electrodes 2 and 3 are moved rightward in FIG. 1 while the electrode tips 9 and 10 are in contact with the gauge 8 as shown in FIG. 3, the gauge 8 is sandwiched between the electrodes 2 and 3. Is moved rightward, and is detected by the sensor 13. This detection means that the polishing is normal since the contact state as shown in FIG. 3 is established. In the state of the shapes 11 and 12 in FIG. 3, the gauge 8 is not pinched, so that even if the electrodes 2 and 3 are moved to the right, the gauge 8 does not protrude to the right. No detection by the sensor 13 is performed. In FIG. 3, when the electrode tips 9 and 10 sandwich the gauge 8, as described above, although not shown, a slight gap is formed between the electrodes 2 and 3 and the recesses 4 and 5. Have been.

FIGS. 1 to 3 show a state in which the gauge 8 is sandwiched between the tip portions 9 and 10 of the electrodes. FIG. 4 shows a state in which one electrode 2 is pressed from one side instead of being sandwiched. It is. In order to move the gauge 8 perpendicularly to the plane of FIG. 4, the gauge 8 is equipped with a moving roller 14, and the gauge 8 is fixed to a bearing 15 thereof.

FIG. 5 shows a case where the gauge 8 is inserted from the outside so as to aim between the tip portions 9 and 10 of the two electrodes. When the electrode tips 9 and 10 are polished normally as shown by the solid line in the figure, the tip of the gauge 8 abuts against the electrode tips 9 and 10 and further advance is restricted. If the code 1
If the polishing is incomplete, such as 1 and 12, the gauge 8 passes through as shown by the two-dot chain line, and the state is detected to confirm that the polishing is defective. An air cylinder 16 is installed to move the gauge 8 forward and backward, and the piston position is detected by sensors 17 and 18 attached thereto,
Signals of normal polishing and abnormal polishing are taken out. Various sensors can be used as the sensors 13, 17, and 18, but a proximity switch is used here.

Next, a specific embodiment will be described with reference to FIGS.
It is explained according to. Members having the same functions as those described above are denoted by the same reference numerals in the respective drawings, and detailed description is omitted. The whole inspection apparatus is indicated by reference numeral 19. The substrate 20 has a rectangular shape made of a steel plate.
The supporting plates 21 and 22 are fixed to both ends in a state where they face each other. Two guide rods 23 and 24 are provided between the support plates 21 and 22 in parallel. Sliding plates 25, 26
Can be moved along guide rods 23, 24, and therefore slide bearings 27, 28, 29 and 30
Guide rods 23 and 24 penetrate the sliding plate 2
Sliding bearings 27 and 28 are fixed to 5, and sliding bearings 29 and 30 are fixed to another sliding plate 26.

The sliding plates 25, 26 protrude from the substrate 20, and are fixed to the two sliding plates 25, 26 in such a manner that the guide member 1 is provided on this portion. Therefore, the sliding plate 2
The guide members 5 and 26 are integrally assembled by the guide member 1 and are configured to be movable along the guide rods 23 and 24. The gauge 8 penetrates the sliding plates 25 and 26 and the guide member 1 in a state as shown in FIG. 8 and is arranged in parallel with the guide rods 23 and 24, and the left end thereof is connected to the gauge sliding plate 31. is there. The gauge sliding plate 31 can also move along the guide rods 23 and 24, and therefore, the sliding bearings 34 and 35 are
3 and 24 penetrate, and both bearings 34 and 35 are fixed to the gauge sliding plate 31.

The concave portions 4 and 5 are elongated gutter-shaped concave grooves 3.
2, 33. A space 7 is formed along the longitudinal direction of the grooves 32, 33 at the bottom of the grooves 32, 33, and the gauge 8 passes through the space 7. In order to arrange the gauge 8 in this manner, through holes as shown are formed in the sliding plates 25 and 26. The proximity switch 13 is attached to a bracket 36 fixed to the substrate 20, and detects the advance of the gauge 8. Further, another bracket 37 is fixed to the substrate 20, and a proximity switch 38 is attached to the bracket 37. This is to set the start position by moving the guide member to the left from the position in FIG. 6, but to detect this position.

The spring guide rod 39 has two support plates 21, 2
2 and is disposed between the two guide rods 23, 24. The spring bearing piece 40 is attached to the sliding bearing 29.
Is fixed, and a first coil spring 41 is interposed between the spring receiving piece 40 and the support plate 22. Further, a second coil spring 42 is interposed between the spring receiving piece 40 and the gauge sliding plate 31. The standby positions of the sliding plates 25 and 26, that is, the guide member 1, and the standby position of the gauge sliding plate 31, that is, the gauge 8 are set by these two coil springs 41 and 42. In order to obtain such a standby position by the two coil springs 41 and 42, the sliding plates 25 and 26 are provided with through holes 43 and 44 for both coil springs. In addition, both guide rods 23,
Stopper rubbers 45 and 46 are attached to the support plate 21 side of 24.

When the electrodes 2 and 3 are inserted into the grooves 32 and 33, it is necessary that the guide member 1 can follow the bias of the electrodes 2 and 3. Describing this follow-up mechanism, auxiliary plates 47 and 48 are connected to both sides of the substrate 20, and support rods 51 and 52 are passed through sliding bearings 49 and 50 fixed thereto with a slightly wide gap.
The support rods 51 and 52 are raised from the stationary member 6 and are elastically supported by support coil springs 53 and 54. Reference numerals 55 and 56 represent support rods 51 and 5.
2 is a stopper piece fixed to the upper end of 2.

As is clear from FIG. 8, the receiving plates 57, 58 fixed above and below the sliding plate 25 are members which are pushed when the guide member 1 is moved by the electrodes. Although not shown, the two electrodes 2 and 3 are provided on a C gun or an X gun operated by, for example, a six-axis robot. It moves near.

The operation of the above embodiment will be described. Before the electrodes fit into the grooves 32, 33, the electrodes are
7 and 58, the guide member 1 moves to the left.
And the sliding plates 25 and 26 move integrally to the left, and the sliding bearing 28 is detected by the proximity switch 38. With this detection signal, the movement to the left is stopped, and the initial position of the guide member 1 is set. At this time, since the gauge sliding plate 31 is pushed leftward by the second coil spring 42, the initial position of the gauge 8 is also set. Thus, the guide member 1
When the initial positions of the gauge 8 and the gauge 8 are set, the gauge 8 slightly protrudes from the guide member 1 (not shown in this case) or protrudes to some extent (shown) by the proximity switch 13. It is easy to detect.

Next, when the electrodes 2 and 3 are fitted into the concave grooves 32 and 33, a state as shown in FIG. 3 is obtained, and the electrode tips 9, 10 sandwich the gauge 8, but the concave grooves 32, 33
There is a slight gap between the electrode and the electrode. When the electrode is moved rightward in this sandwiched state, the gauge 8 moves to the proximity switch 13 and is detected, and it is confirmed that the polishing shape is good. Since the receiving plates 57 and 58 remain in contact with the electrodes due to the tension of the second coil spring 42 during this movement, the relative position between the gauge 8 and the guide member 1 is unchanged via the electrodes. The length protruding from the guide member 1 does not change. During the rightward movement, the first coil spring 41 is compressed to provide a restoring force to the original position.

When the polished shape of the electrode is defective as shown by reference numerals 11 and 12 in FIG. 3, the tip of the electrode does not come into contact with the gauge 8 but comes into close contact with the concave grooves 32 and 33 only. When the electrode is moved rightward in this state, the gauge 8 remains stopped at the initial position by the tension of the second coil spring, and only the guide member 1 moves rightward. Therefore,
Since the gauge 8 does not reach the detection area of the proximity switch 13, no signal is emitted therefrom. Thus, the state in which only the guide member 1 is moved rightward is detected, and it is confirmed that polishing is defective. Although a detecting means for this is not shown, a sensor (proximity switch) for detecting the movement of the guide member 1 is attached to the substrate 20 with the same structure as the proximity switch 13, and a signal from this sensor and a signal from the proximity switch 13 are provided. This is combined with the fact that no polishing occurs, and a polishing failure is detected.

According to the above-described operation, when the polishing shape is correct, the gauge 8 is surely moved and it can be confirmed that the polishing is normal. This is because the gauge is moved on the basis of the protruding state of the electrode tips 9 and 10 as shown in FIG. 3, so that the unstable detection that depends on the change of the electric value as in the prior art is avoided. can do. Also, skill such as visual observation is not required. When the gauge 8 is sandwiched between the electrode tips 9 and 10 having the correct shape, a gap exists between the electrodes 2 and 3 and the concave grooves 32 and 33 of the guide member 1 so that only the gauge 8 can be formed. Can be moved, the gauge movement can be reliably detected, and the normal polishing can be accurately inspected.

Since the gauge 8 and the guide member 1 are supported by the guide rods 23 and 24 so that they can slide independently of each other, when the gauge 8 and the guide member 1 are stopped at the initial position, The length L3 at which the gauge 8 protrudes from the guide member 1 can be secured, and therefore, it is easy to detect the L3 portion with the sensor 13.

When checking the electrodes provided on the robot device by approaching the inspection device 19, the electrodes must be able to match the guide member 1 even if there is some displacement. For this purpose, a follow-up mechanism including the support rods 51 and 52 and the support coil springs 53 and 54 is held, so that it can be operated accurately even in a fully automated production line.

Since the guide rods 23 and 24, the sliding members for the guide member 1 and the gauge 8 and the like are arranged on the substrate 20, the unit as the inspection device 19 is very compact.

In the above-described embodiment, if the gauge 8 protrudes from the guide member 1 over a required length, the electrode comes into contact with both the concave groove and the gauge, and the gauge 8 and the guide member 1 are simultaneously moved. Is also good.

Another embodiment shown in FIG. 9 will be described. This is a case where the principle of FIG. 5 is reversed. The same members as those in the previous embodiment are denoted by the same reference numerals in the drawings. A cylinder 60 is fixed on a substrate 59, and a piston 62 is inserted into a first cylinder 61 of the cylinder. A tension of a return spring 63 acts on this. A guide member 1 is formed on a member corresponding to a piston rod of a piston 62, and a gauge 8 is inserted into a space 7 provided therein. The gauge 8 penetrates through the second cylinder 64 and slightly projects outside the cylinder 60. A flange 65 is fixed to the gauge 8, and a tension of a return spring 66 acts on the flange 65. A cushioning rubber 68 is interposed between the support 67 and the substrate 59 which stand up on the stationary member 6. The cushion rubber 68 is provided to obtain the following function. Reference numeral 69 denotes a stopper piece.

When the electrodes 2 and 3 inserted into the concave grooves 32 and 33 are moved to the right in the figure as shown by the two-dot chain line, if the electrodes are in a normal polishing state, the electrodes and the gauge 8 will be The relationship is as shown in FIG. Then, the gauge 8 is pushed rightward and protrudes to the position shown by the two-dot chain line, and the proximity switch 1
3 to confirm that the polishing is normal. When the gauge 8 is moved to the right, the return spring 66 is compressed, and the restoring force is accumulated. Further, when the electrode hits the piston 62, the return spring 63 is compressed and the restoring force is stored.

In this embodiment, since the inspection device is in a cantilevered state from the column 67, the electrode is
There is an advantage that it is easy to approach 2, 33. Further, since the structure in which the piston 62, the gauge 8, and the like are accommodated in the cylinder 60 is used, the inspection apparatus is extremely simplified and slim, and is very advantageous in terms of equipment costs.

Although not described in the claims, when the tip of the electrode is in contact with the gauge, a gap is provided between the electrode and the concave portion or the concave groove, so that when the electrode is normal, Only the gauge can be reliably moved and detected. On the other hand, in the case of an abnormal electrode, only the guide member can be moved while leaving the gauge, so that this movement can be detected and a polishing abnormality can be confirmed. . Here, the gauge is checked when it is normal, and the guide is checked when it is abnormal. Obtaining check information from a different member is convenient in terms of accuracy as an inspection method.

[0032]

According to the present invention, the guide member is provided with a concave portion corresponding to the shape of the tip of the electrode, a space for inserting a gauge is formed at the bottom of the concave portion, and the electrode having a normal shape is fitted into the concave portion. When the electrode tip is projected into the space, the electrode tip is brought into contact with the gauge, and the normal shape of the electrode tip is detected. This serves as a basis for the determination, and therefore, the instability that is detected by a change in the electrical value as described in the related art can be avoided. In particular, since it depends on the state of the tangible object, high inspection reliability can be obtained. In addition, it is not necessary to perform inefficiency such as performing inspection with the naked eye. Then, when the electrode tip is in contact with the gauge, it is normal, and when it is not, it is abnormal, so that the quality can be determined very clearly. Further, since the contact state is used as a basis, the gauge can perform various types of motion as described with reference to FIGS. 1 to 5.

The concave portion is formed in a gutter shape, and the electrode is moved along the concave portion while the tip of the electrode is in contact with the gauge. The movement causes the gauge to protrude from the guide member. This is a method for confirming that the tip has a normal shape. Therefore, when the electrode is moved, the electrode is guided along the concave portion, so that the electrode can be accurately moved. This is very advantageous from an inspection step where precision is important because it is essential that the electrode movement and the gauge movement are paired. Further, as an important effect, an inspection method suitable for the movement of the robot is required in an automatic welding line equipped with a large number of complicated robot devices. In the present invention, since the electrode moves along the concave groove after fitting into the concave groove, a large displacement can be generated in the gauge by appropriately selecting the length of the concave groove, It is very easy to detect the amount of movement of the gauge, and unattended inspection can be performed on an automatic welding line.

Since a gauge is inserted from the outside and the gauge is applied to the tip of the electrode, it can be clearly determined that the polishing is normal if the insertion gauge stops, and that the polishing is abnormal if the insertion gauge does not stop.

According to the invention of the device, a gutter-shaped groove is provided on the guide member so as to conform to the shape of the electrode tip, and a space for inserting a bar-shaped gauge at the bottom of the groove extends along the longitudinal direction of the groove. The guide member and the gauge are formed so as to be slidably supported by the guide rod, and the guide member and the gauge are configured to be slidable independently of each other. Therefore, when the electrode is moved in conformity with the groove, the gauge is moved if the polishing is normal, and it can be reliably detected that the electrode is normal. And since the guide member and the gauge are slidably supported on the guide rod in an independent state, the initial positions of the guide member and the gauge are individually obtained, and the relative position between the gauge and the guide member is inspected. It can be suitable. Also,
When the polishing is poor, there is no contact between the tip of the electrode and the gauge, so there is no movement of the gauge, which can be detected to clearly detect poor polishing.

[Brief description of the drawings]

FIG. 1 is a simplified side view showing the present invention in principle.

FIG. 2 is a sectional view taken along line (2)-(2) of FIG.

FIG. 3 is a longitudinal sectional front view in which main parts are enlarged.

FIG. 4 is a longitudinal sectional front view showing another type.

FIG. 5 is a simplified side view showing still another type.

FIG. 6 is a plan view of an apparatus for performing the method of the present invention.

FIG. 7 is a side view of that of FIG.

FIG. 8 is a sectional view taken along line (8)-(8) of FIG. 6;

FIG. 9 is a side view showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Guide member 2, 3 Electrode 4, 5 Concave part 8 Gauge 7 Space 9, 10 Electrode tip part 32, 33 Concave groove 23, 24 Guide rod 19 Inspection device

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F069 AA66 BB02 BB40 DD24 DD25 GG01 GG52 GG71 GG75 MM02 RR05

Claims (4)

[Claims] The guide member is provided with a concave portion corresponding to the tip shape of the electrode, a space for inserting a gauge is formed in the bottom portion of the concave portion, and when the electrode having a normal shape is fitted in the concave portion, the electrode tip portion is formed. A method for inspecting a tip shape of a spot welding electrode, wherein a normal shape of the electrode tip is detected by projecting the tip of the electrode into a space to contact the gauge. 2. The method according to claim 1, wherein the recess has a gutter shape.
The electrode is moved along the recess while the electrode tip is in contact with the gauge, and this movement causes the gauge to protrude from the guide member, and detects this protruding state to confirm that the electrode tip has a normal shape. A method for inspecting a tip shape of a spot welding electrode, characterized in that the method is performed. 3. The spot according to claim 1, wherein the gauge inserted from outside hits the electrode tip projecting into the space to confirm that the electrode tip has a normal shape. Inspection method of tip shape of welding electrode. 4. An apparatus for carrying out the method according to claim 2, wherein the guide member is provided with a trough-shaped groove conforming to the shape of the electrode tip, and a bar-shaped gauge is provided at the bottom of the groove. A space to be inserted is formed along the longitudinal direction of the groove, the guide member and the gauge are slidably supported by the guide rod, and the guide member and the gauge can slide independently of each other. An apparatus for inspecting the shape of the tip of a spot welding electrode, characterized in that: