KR101336648B1 - Welded state detection apparatus of spot welding robot - Google Patents

Abstract

The present invention relates to a spot welding robot welding condition sensor capable of observing an electrode cap of a spot welding robot performing the spot welding at high speeds in real time in order to assemble the panel of a car body, improve productivity by immediately indicating that the observed electrode cap is damaged and immediately repairing the defect welding due to the damage of an electrode cap, and significantly improving the reliability of the product by clearly displaying, on the panel of the car body subjected to the defected welding, spot welding which is performed in a state where the electrode cap is damaged. The spot welding robot welding condition sensor of the present invention is further mounted with a vibration sensor (30) for detecting the vibration number of the electrode cap in at least one electrode arm among an electrode arm (10) in the upper part or an electrode arm (50) in the lower part and includes a spraying nozzle (40) for displaying the location at the welding point of the panel to be welded in a case where the damage signal of the electrode cap is transmitted from an analysis control unit (80). The present invention is capable of significantly improving the reliability and productivity of a product by efficiently detecting the welding defect due to the damage of the electrode cap mounted in the spot welding robot by obtaining information on the welding quality in real time in the spot welding process for assembling the panel of the car body.

Description

Spot welding robot welding condition detection device {WELDED STATE DETECTION APPARATUS OF SPOT WELDING ROBOT}

The present invention observes the electrode cap of the spot welding robot that performs spot welding at high speed in order to assemble the panel of the vehicle body in real time, and if the observed electrode cap is damaged, it immediately warns it of poor welding due to damage of the electrode cap. If this occurs, it can be immediately repaired to greatly improve productivity, and spot welding is performed while the electrode cap is damaged to clearly display it on the poorly welded body panel, thereby greatly improving product reliability. The present invention relates to a welding state detection apparatus for a spot welding robot.

In general, a vehicle body may be divided into a front body, an under body, a cowl, a side body, a roof, and a rear body.

In the assembly of such a vehicle body, spot resistance welding is frequently used as a method of welding two panels, and the spot resistance welding is performed by applying a pressing force to the surface of the vehicle body panel using a spot welding robot. As described above, in the one-way spot welding gun device, a welding gun driving cylinder 110 is installed on a fixed bracket mounted to the arm tip of the robot, and a welding gun is mounted on the operation rod 112 of the welding gun driving cylinder 110. It is composed. Wherein the welding gun is composed of an electrode arm 10 and the electrode cap (11).

The spot welding robot is used to determine the welding position and welding angle of the welding gun by moving the robot to the position of the panel 114 at the first time in order to automatically repeat welding with a welding gun device robot for a new car development or a new welding point. It is configured to automatically repeat the program by storing the position in the robot. In addition, the spot welding robot as described above is connected to the forward and backward operation of the welding gun driving cylinder 110 with respect to the two panels 114 to be welded to conduct electricity by bringing the panel 114 into contact with the welding gun. do.

Spot welding robot according to the conventional embodiment as described above, as shown in Figure 5, in the line for welding the panel material of the vehicle body production line, using a spot welding system using a spot welding robot 100, etc. Resistance welding will be performed.

Such electric resistance welding is given an initial input condition such as current, resistance, and energization time, where the resistance is an electrode cap (11 in FIG. 6) mounted on the upper and lower electrode arms 10 and 50 of the spot welding gun unit. The contact cross-sectional area of is greatly affected. That is, the spot welding robot 100 is a C-type, the lower electrode arm 50 and the upper electrode on the gun body 60 mounted on the tip of the robot arm 120 of the spot welding robot 100 A welding gun driving cylinder 110 including an arm 10 and generating a pressing force by driving the upper electrode arm 10 on one side is configured. Here, reference numeral 140 denotes a welding robot operating panel, and reference numeral 150 denotes an indicator light.

Meanwhile, electrode caps 11 and 51 are mounted to the electrode arms 10 and 50 to perform spot welding. These electrode arms 10, 50 are placed in appropriate positions to access the panels that are welded together. For the panels to be welded together, the precise placement of the gun body 60 and the placement of the panels together are automatic and performed by the computer of the welding robot operating group 140. With this automated production line, high-speed fixed cycles can be achieved and the welding operation is not hindered.

The electrode cap coupled to the electrode arm used in this process is in contact with the panel of the vehicle body to be welded to each other, so the damage caused by abrasion is very large. During the welding process, current flows between the electrodes and, as a result, flows through the panels of the vehicle body that are already in intimate contact with each other.

The contact surface of the electrode cap undergoes a change in the area where the welding process takes place. For example, the electrodes are often burned and destroyed in the edge area of the contact surface, the material is piled up and the contact surface is stretched, eventually changing the welding conditions.

Because of this change, it is very uneconomical to track and adjust the strength of the current, so to avoid this, the electrode cap is regularly milled according to the applied load and damage caused by wear.

In most cases, the electrodes interacting with the same gun body have the same wear and therefore need to be reworked by milling regularly and simultaneously. However, after several milling operations, the material consumed in the electrode cap is greatly reduced, and needs to be replaced.

The task is to remove the worn electrode cap from the electrode arm of the welding electrode. Magazines with a simple structure may be used to supply new and unconsumed electrode caps to the electrode arms of the welding electrodes.

These magazines are not available for reloading during welding due to safety reasons because there are no people in the operating area where the robot operates or because they cannot walk into the operating area. There have been attempts to do so.

However, since the electrode cap mounted on the spot welding robot running at a high-speed fixed cycle cannot predict when and at what time, there is a problem in that the defective rate of the product due to the defective electrode cap cannot be effectively reduced.

On the other hand, Korean Patent Laid-Open No. 2012-0050411 (published: 2012. 05. 18.) discloses an electrode inspection apparatus for spot welding. The spot welding electrode inspection device can accurately measure the electrode tip diameter without lowering the operation rate of the production line. That is, the CCD camera for photographing the electrode tip held in the welding gun is provided in the inspection apparatus main body.

The inspection apparatus main body includes a measurement reference portion having a fixing hole for fixing the electrode tip, and a mirror inclined with respect to the electrode so as to be spaced apart from the fixing hole on the side opposite to the electrode in the measurement reference portion, The CCD camera is configured to photograph the front of the electrode tip reflected and reflected from the mirror.

However, even when using the conventional spot welding electrode inspection apparatus as described above, there is a problem that it is not possible to obtain the information on the welding quality by grasping in real time the damage of the electrode cap mounted on the spot welding robot that operates at a high-speed fixed cycle. In other words, the panel of the vehicle body that is spot welded at a high speed cannot determine which spot welding process is performed due to the damage of the electrode cap. will be.

The present invention has been proposed to solve the above-mentioned problems, and observe the electrode cap mounted on the spot welding robot performed at high speed in real time to obtain information on the welding quality by the welding gun of the spot welding robot, the electrode It is an object of the present invention to provide a welding state detection device for a spot welding robot that can immediately detect a damaged cap and immediately detect a bad welding caused by damage of an electrode cap, thereby greatly improving productivity.

In addition, it is an object of the present invention to provide a welding state detection device for a spot welding robot that can significantly reduce the defect rate while greatly improving the reliability of the product by clearly displaying this on the body panel on which the spot welding was performed in a damaged electrode cap.

The welding state detection apparatus of the spot welding robot according to the present invention for achieving the above object, is mounted to one end of the spot welding robot and the electrode cap for performing spot welding, coupled with the electrode cap and the one side on the Analysis control unit 80 for determining the state of the electrode cap by receiving a detection signal from the electrode arm is equipped with a temperature sensor 20 for measuring the temperature of the electrode cap, the temperature sensor 20 mounted on the electrode arm In the welding state detection apparatus of the spot welding robot comprising a, the electrode arm is at least one of the upper electrode arm 10 or the lower electrode arm 50, the electrode arm, the frequency of the electrode cap Further equipped with a vibration sensor 30 for detecting the, and when receiving the damage signal of the electrode cap from the analysis control unit 80 includes a spray nozzle 40 for indicating the position at the welding point of the panel to be welded Characterized in that the configuration.

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As described above, according to the present invention, in the spot welding process for assembling the vehicle body panel, information about welding quality is obtained in real time to effectively detect welding defects due to damage of the electrode cap mounted on the spot welding robot, thereby ensuring the reliability of the product. And the productivity can be greatly improved.

In other words, the electrode cap mounted on the spot welding robot performed at high speed is observed in real time, and if the electrode cap is damaged, it is immediately alerted, and in case of poor welding due to the damage of the electrode cap, it is immediately detected. Productivity can be greatly improved.

In addition, when the electrode cap is damaged, there is an effect that the spot welding is clearly displayed on the body panel on which the spot welding is performed, thereby greatly reducing the defect rate while greatly improving the reliability of the product.

1 is a schematic configuration diagram of a spot welding robot equipped with a welding state detection apparatus according to an embodiment of the present invention,
2 is a schematic control configuration diagram of a spot welding robot equipped with a welding state sensing apparatus according to an embodiment of the present invention;
3 is a cross-sectional view of a welding gun in a spot welding robot equipped with a welding state detection device according to an embodiment of the present invention;
Figure 4 is a schematic control block diagram of the analysis control unit for observing and analyzing the electrode cap in the welding state detection apparatus of the spot welding robot according to an embodiment of the present invention,
5 and 6 is a schematic configuration diagram of a spot welding robot according to a conventional embodiment.

Hereinafter, a welding state detection apparatus for a spot welding robot according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic configuration diagram of a spot welding robot equipped with a welding state sensing apparatus according to an embodiment of the present invention, Figure 2 is a spot welding robot equipped with a welding state sensing apparatus according to an embodiment of the present invention It is a schematic control diagram.

3 is a cross-sectional view of a welding gun in a spot welding robot equipped with a welding state sensing apparatus according to an embodiment of the present invention, and FIG. 4 is a welding state sensing apparatus of a spot welding robot according to an embodiment of the present invention. Figure is a schematic control block diagram of the analysis control unit for observing and analyzing the electrode cap.

In the drawings, the same reference numerals are given to the same elements even when they are shown in different drawings. In the drawings, the same reference numerals as used in the accompanying drawings are used to designate the same or similar elements. And detailed description of the configuration will be omitted. Also, directional terms such as "top", "bottom", "front", "back", "front", "forward", "rear", etc. are used in connection with the orientation of the disclosed drawing (s). Since the elements of the embodiments of the present invention can be positioned in various orientations, the directional terminology is used for illustrative purposes, not limitation.

The welding state detection apparatus of the preferred spot welding robot according to an embodiment of the present invention is mounted on one end of the spot welding robot as shown in Figure 1 to 4, the electrode cap (11) for performing spot welding 51, an electrode arm (10, 50) coupled to the electrode cap (11, 51) and equipped with a sensor for measuring the temperature or frequency of the electrode cap (11, 51) on one side; Receiving a detection signal from the sensors mounted on the (10, 50) and the analysis control unit 80 to determine the state of the electrode cap (11, 51), and receiving the damage signal of the electrode cap from the analysis control unit 80 In this case, it is configured to include a spray nozzle 40 for indicating the position at the welding point of the panel to be welded.

In addition, it is preferable that the injection nozzle 40 is configured to further include an alarm 70, such as a landscape lamp or a horn to alert it visually or audibly when it is operating. Here, the alarm 70 is preferably mounted on one end of the spot welding robot, but is not limited thereto. In other words, it will be anywhere if the position where the alarm 70 can be easily observed.

On the other hand, it is also known as a welding gun including the electrode arm (10, 50) to which the electrode cap (11, 51) is coupled, and the gun body 60 for supporting it. However, in the present invention, the electrode arm and the electrode cap are briefly referred to as welding guns, and the shape to be applied may be changed according to the shape of the welding gun.

The spot welding robot 100 is a C-type as known, the lower electrode arm 50 on the C-shaped gun body 60 mounted on the tip of the robot arm 120 of the spot welding robot 100 And an electrode arm 10 of the upper portion, and a welding gun driving cylinder 110 for generating a pressing force by driving the upper electrode arm 10 is configured. In addition, the welding robot operating panel 140 for controlling and programming the operation of the spot welding robot 100, and the indicator 150 for displaying the operation and status of the spot welding robot 100, It is composed. In addition, electrode caps 11 and 51 are mounted on the electrode arms 10 and 50 to perform spot welding. These electrode arms 10, 50 are placed in appropriate positions to access the panels that are welded together. For the panels to be welded together, the precise placement of the gun body 60 and the placement of the panels together are automatic and performed by the computer of the welding robot operating group 140. This automated production line enables high speed fixed cycles.

As shown in FIG. 3, the electrode caps 11 and 51 have a cap shape in which the inside is hollow and one side is opened toward the electrode arms 10 and 50.

As shown in FIG. 3, the electrode arms 10 and 50 have a hollow tubular shape connected to a welding gun driving cylinder 110 for operating the welding gun. In the present invention, the vibration for detecting the frequency of the temperature sensor 20 or the electrode cap (11, 51) for detecting the temperature of the electrode cap (11, 51) on one side of the electrode arm (10, 50) The sensor 30 is mounted. In the embodiment of the present invention, in order to more clearly analyze the state of the electrode caps 11 and 51, both the temperature sensor 20 and the vibration sensor 30 will be described.

Here, the temperature sensor 20 or the vibration sensor 30 is attached to the electrode arms 10 and 50 by a known method, and any method may be used in the present invention. In other words, it can be attached by screw, banding, fitting, adhesive.

As shown in FIG. 4, the analysis controller 80 receives a detection signal from a sensor mounted on the electrode arms 10 and 50. The analysis control unit 80 includes a calculation unit 85, a determination unit 86, and a data storage unit 87.

In addition, the analysis controller 80 outputs a signal indicating whether the electrode caps 11 and 51 are damaged or normal to the injection nozzle 40. On the other hand, it is preferable that the analysis results of the analysis control unit 80 is configured to be displayed through the display unit 90.

The calculation unit 85 of the analysis control unit 80 receives the temperature of the electrode caps 11 and 51 from the temperature sensor 20 and measures the temperature. During welding, the temperature rises to about 1300 ° C. near the electrode caps 11 and 51. Therefore, as described below, the inside of the electrode arms 10 and 50 and the electrode caps 11 and 51 are formed with a hollow cooling water passage 173, and the cooling water flows along the cooling water passage 173 to form the electrode cap. The vicinity is appropriately cooled.

However, the electrode caps 11 and 51 are often burned away in the edge region of the contact surface during welding, and the temperature changes as the welding conditions change due to the accumulation of material and the contact surface.

Therefore, the change in temperature is measured by the calculation unit 85.

The determination unit 86 of the analysis control unit 80 stores the temperature values of the electrode caps 11 and 51 stored in advance. In other words, the temperature conditions of the allowed electrode caps 11 and 51 are input in advance, and the state of the electrode caps 11 and 51 is determined by comparing with the temperature values input through the calculation unit 85. In other words, if it is a temperature condition in which poor welding can occur, a damage of the electrode cap is output, and otherwise, a normal state is output.

However, the temperature storage unit may store the calculated value and the determination value for a certain period of time by compensating for the temperature condition because the temperature condition in which bad welding may occur is not always constant according to the working condition or the environmental condition. It is stored at (87).

On the other hand, the analysis control unit 80 may receive the measurement value from the vibration sensor 30 mounted on the electrode arms (10, 50). In this case, the calculation unit 85 measures the frequency generated by the electrode caps 11 and 51 during welding. In addition, the determination unit 86 determines whether it is a vibration condition in which poor welding can occur as described above, and the data is stored in the data storage unit 87.

The display unit 90 displays the determination result of the analysis control unit 80, and is preferably mounted at a position where the operator who manages the spot welding robot 100 can be immediately notified. In addition, when the determination result of the analysis control unit 80 is a damage signal, it is also preferable to be able to quickly alarm through a short-range wireless communication network to notify the operator at a remote location.

The spray nozzle 40 sprays the pre-stored paint onto the panel so that the welded position can be clearly identified. In other words, when spot welding is performed while the electrode caps 11 and 51 are damaged or contaminated, a damage signal is input from the analysis controller 80 to perform such an operation. This poor welding makes it possible to easily detect the position of the panel or poor welding in which the welding failure occurred in a large number of products produced in the process running at high speed.

Meanwhile, as described above, in the welding operation by the spot welding gun, the spot welding gun includes a cooling device to cool the welding heat generated at the electrode caps 11 and 51. That is, during welding, the temperature rises to about 1300 ° C. near the electrode cap. Therefore, fusion (poor welding) will occur if the vicinity of the electrode cap is not properly cooled, so cooling during spot welding is essential.

Cooling means for cooling the conventional spot welding gun is water-colling (water-colling). Background Art A conventional apparatus for cooling a spot welding gun is cooling by supplying cooling water stored in an external cooling water tank by a pump to a conduit provided inside the spot welding gun.

As shown in FIG. 2, the cooling system includes a cooling pipe 170 through which cooling water flows. And, it includes a cooling water pump, a pump connected to the tank located outside.

The cooling pipe 170 to absorb the welding heat generated in the vicinity of the electrode arm (10, 50) and the electrode cap (11, 51), as shown in Figure 3 the electrode arm (10, 50) and the electrode The coolant flows through the coolant paths 173 formed in the caps 11 and 51, and the coolant is operated by the control of the cooling switch 171 connected to the cooling signal line 172.

Meanwhile, a pneumatic pipe 160 for driving the welding gun driving cylinder 110 is configured together with the cooling system, and a power cable 130 and a power control unit for supplying power to the electrode arms 10 and 50. 131 is configured.

In addition, the present invention has been described on the premise that the temperature sensor 20 or the vibration sensor 30 is mounted on both the upper electrode arm 10 and the lower electrode arm 50 as described above. Obviously, it can be mounted and operated on only one part of the device.

It looks at the effect of the welding state detection device of the spot welding robot of the present invention configured as described above.

First, the electrode arms 10 and 50 of the present invention constituting the welding gun are equipped with a temperature sensor 20 and a vibration sensor 30 to measure the temperature and the frequency of the electrode caps 11 and 51.

The detection value of this sensor is transmitted to the analysis control unit 80 via the detection signal line 81.

On the other hand, the injection nozzle 40 is mounted in the vicinity of the welding gun, this injection nozzle 40 is configured to be able to supply paint through the paint supply means not shown.

As is well known, the spot welding robot 100 is driven and operated through a welding robot operating panel 140 for controlling and programming the operation of the spot welding robot 100. This operation allows the welding gun to be placed in the proper position, accesses the panels to be welded together, and arranges these panels with each other and the computer of the welding robot operating group 140 to automatically access the welding gun. Is performed by. Therefore, a fast fixed cycle can be achieved due to the automated production line.

The spot welding robot 100 which runs at a high speed in such a fixed cycle, the temperature is raised to about 1300 ℃ in the vicinity of the electrode cap (11, 51) when spot welding is performed. In addition, the electrode caps (11, 51) is often burned away at the edge region of the contact surface during welding, or the material is accumulated to increase the contact surface, eventually changing the welding conditions. Therefore, fusion (poor welding) occurs and defective products are produced.

Such a welding failure condition is likely to occur when the temperature conditions or vibration conditions of the electrode caps 11 and 51 are not high, and the present invention is mounted on the electrode arms 10 and 50. The temperature sensor and the vibration sensor 30 detect such a temperature signal and a frequency signal, and the detected signal is analyzed in real time through the analysis controller 80 to detect a temperature signal or vibration signal in a bad condition. do.

When such a bad signal is detected through the analysis control unit 80, the analysis control unit 80 controls the injection nozzle 40 to be operated while allowing the operator to recognize it immediately through the display unit 90. Output the signal. Therefore, the display is automatically performed through the injection nozzle 40 so that an operator can easily identify the welding position of the panel that was performed when the bad signal is detected.

On the other hand, when such poor welding is performed, the operator is also alerted through the alarm 70 mounted near the welding gun, and at the same time, such data is stored in the analysis control unit 80 so as to more accurately correct the reliability of the alarm operation. do.

Therefore, the present invention obtains the information on the welding quality in the spot welding process for assembling the vehicle body in real time to effectively detect the welding defects caused by the damage of the electrode cap mounted on the spot welding robot to greatly improve the reliability and productivity of the product. It becomes possible.

The embodiments of the present invention described above and shown in the drawings should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art will be able to modify the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the scope of the present invention if they are apparent to those skilled in the art.

10, 50: electrode arm 11, 51: electrode cap
20: temperature sensor 30: vibration sensor
40: spray nozzle 60: gun body
70: alarm 80: analysis control unit
81: detection signal line 85: calculator
86: judgment unit 87: data storage unit
90: display unit 100: spot welding robot
110: welding gun driving cylinder 120: robot arm
130: power cable 131: power control unit
140: welding robot operation panel 150: indicator light
160: pneumatic piping 170: cooling piping
171: cooling switch 172: cooling signal line

Claims (3)

An electrode arm mounted on one end of the spot welding robot and configured to perform spot welding, an electrode arm coupled to the electrode cap and equipped with a temperature sensor 20 on one side thereof to measure the temperature of the electrode cap; In the welding state detection apparatus of the spot welding robot comprising an analysis control unit 80 for receiving the detection signal from the temperature sensor 20 mounted on the electrode arm to determine the state of the electrode cap,
The electrode arm is at least one of the upper electrode arm 10 or the lower electrode arm 50,
The electrode arm is further equipped with a vibration sensor 30 for detecting the frequency of the electrode cap,
When receiving the damage signal of the electrode cap from the analysis control unit 80, the welding state detection of the spot welding robot, characterized in that it comprises a spray nozzle 40 for indicating the position at the welding point of the panel to be welded Device. delete delete

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