JP4837425B2 - Inspection method and apparatus for spot welds - Google Patents

Description

  The present invention relates to an inspection method and apparatus for automatically determining whether or not a spot welded portion is nondestructive using ultrasonic waves.

  Spot welding is frequently used to join metal panels in the automobile industry and the like, and it is necessary to perform a quality inspection of the spot welded portion. Conventionally, the pass / fail determination is performed by the vertical destructive inspection, but since the loss of destruction of the broken parts occurs, in recent years, nondestructive inspection using ultrasonic waves has begun to be used. This non-destructive inspection is performed manually by an operator by pressing the ultrasonic probe against the spot welded portion, so that skill is required for the operation, and inspection results vary from worker to worker.

On the other hand, Japanese Patent Application Laid-Open No. H10-260260 discloses a device that automatically performs an inspection by controlling the operation of an ultrasonic sensor using a robot. According to this document, the robot performs inspection by aligning the ultrasonic sensor with the spot welded portion based on the welded portion position information existing in advance in the ultrasonic inspection apparatus. At that time, if the ultrasonic signal does not reach the predetermined reference due to the actual welding position deviating from the weld position information, the robot moves the ultrasonic sensor until the ultrasonic signal satisfies the reference, and the inspection is performed. Like to do.
Germany 10125782 Publication

  However, in the case of Patent Document 1, since the ultrasonic sensor is moved by the robot and the pass / fail judgment is made at the first point where the ultrasonic signal satisfies the above-mentioned standard, the best inspection that the ultrasonic sensor should originally determine is determined. There is a risk of performing a pass / fail determination before reaching the position to make an erroneous determination.

  Therefore, an object of the present invention is to improve the reliability of the pass / fail determination for the ultrasonic inspection of the spot welded portion using a robot.

The present invention has been made in view of the circumstances as described above, and a spot welded portion inspection method according to the present invention uses a robot to abut an ultrasonic sensor, which is a contact-type ultrasonic probe, on a workpiece surface. Scanning in a plurality of directions while changing the position of the ultrasonic sensor with respect to the workpiece, transmitting ultrasonic waves at a plurality of positions to one spot welded portion, a plurality of the spot welded portions The intensity of the reflected wave detected at the point is distributed on the position coordinates by the data processing device, and the data processing device uses the deflection amount for each scanning direction caused by the load caused by the friction with the workpiece when the ultrasonic sensor is scanned. the position coordinates of the reflected wave intensity corrected, and wherein the row Ukoto the quality check of the spot weld on the basis of the intensity distribution of the reflected wave Te.

In this case, when there are a plurality of scanning directions of the ultrasonic sensor, the direction of the bending caused by the load caused by friction with the workpiece is different at the time of scanning of the ultrasonic sensor. However, since the position coordinate of the reflected wave intensity is corrected in consideration of the amount of deflection in each scanning direction, the correct intensity distribution of the reflected wave can be obtained, and pass / fail judgment based on the intensity distribution state of the reflected wave can be obtained. The accuracy is dramatically improved.

The data processing device may create a distribution map that displays the intensity of the reflected wave on position coordinates, and check the quality of the spot welded portion based on the intensity distribution state of the distribution map.

In this way, since the pass / fail confirmation is performed based on the intensity distribution state (for example, the intensity distribution shape and the number of specific intensity regions) of the distribution map, the accuracy of the pass / fail judgment is dramatically improved.

The position where the intensity of the reflected wave is maximized among the plurality of positions is detected, the position is corrected using a deflection amount caused by a load caused by friction with a workpiece during scanning of the ultrasonic sensor, and the detected position The quality determination of the spot weld may be further performed using the measurement data of the ultrasonic sensor.

In this way, the position where the intensity of the reflected wave is maximized is corrected in consideration of the bending caused by the load caused by friction with the workpiece during scanning of the ultrasonic sensor. Can be obtained correctly.

  The posture of the ultrasonic sensor with respect to the workpiece is also changed by the robot, and ultrasonic waves are transmitted in a plurality of postures to one spot welded portion, and the posture in which the intensity of the reflected wave is maximum among the plurality of postures and positions, and The position may be detected, and the quality of the spot welded part may be determined using measurement data of the ultrasonic sensor at the detected posture and position.

In this way, a plurality of postures and positions of the ultrasonic sensor for each spot welded portion are tested by the robot, and the posture and position at which the intensity of the reflected wave is maximum among the plurality of postures and positions are finally used for inspection. Therefore, it is possible to always judge whether the spot welded portion is good or bad at the best inspection posture and inspection position, thereby enabling high-precision inspection. In addition, since the ultrasonic inspection is performed while changing not only the position of the ultrasonic sensor with respect to the workpiece but also the posture, it is possible to ensure that the posture of the ultrasonic sensor is in the best state unlike the conventional case.

While changing the posture of the ultrasonic sensor with respect to the workpiece by the robot, the ultrasonic sensor transmits an ultrasonic wave to one point of the spot welded portion to detect the optimum posture in which the intensity of the reflected wave is maximized, Optimum intensity of reflected wave is maximized by scanning the spot weld with the ultrasonic sensor by moving the ultrasonic sensor relative to the workpiece with the robot while maintaining the optimal posture. A position may be detected, and the quality of the spot welded part may be determined using measurement data of the ultrasonic sensor at the optimal posture and the optimal position.

While changing the posture of the ultrasonic sensor with respect to the workpiece by the robot, the ultrasonic sensor transmits an ultrasonic wave to one point of the spot welded portion to detect the posture where the intensity of the reflected wave is maximized, The spot sensor is scanned with the ultrasonic sensor to maximize the intensity of the reflected wave by moving the ultrasonic sensor relative to the workpiece while the detected posture is maintained. Detecting an optimum position, and further changing the posture of the ultrasonic sensor with respect to the workpiece at the optimum position by the robot, and sending an ultrasonic wave with the ultrasonic sensor to obtain an optimum posture that maximizes the intensity of the reflected wave The spot welded portion may be judged to be good or bad using the measurement data of the ultrasonic sensor at the optimum posture and the optimum position.

  A position of the spot weld on the workpiece may be detected by a visual sensor, and an initial position of the ultrasonic sensor may be determined based on the detected position.

  In this way, since the position of the spot welded portion on the workpiece is grasped by the visual sensor and the ultrasonic sensor is positioned with respect to the spot welded portion, the accuracy of the initial position of the ultrasonic sensor is improved.

  An orientation of the surface of the spot weld on the workpiece may be detected by a visual sensor, and an initial posture of the ultrasonic sensor may be determined based on the orientation of the surface.

  In this way, the orientation of the ultrasonic sensor with respect to the spot welded portion is determined after the orientation of the surface of the spot welded portion on the workpiece (for example, the direction perpendicular to the surface) is determined by the visual sensor. Will improve.

  When continuously inspecting a plurality of workpieces, the optimal posture and the optimal position of the ultrasonic sensor used for the quality determination at the previous inspection may be used as the initial posture and position of the current inspection.

  In this way, when a plurality of workpieces are continuously inspected, the locations of each spot welded portion are substantially the same, and the posture and position of the ultrasonic sensor used for the pass / fail judgment at the previous inspection are the posture and position of the current inspection. Therefore, the accuracy of the initial posture and the initial position of the ultrasonic sensor with respect to the spot welded portion is improved.

The spot welded portion inspection apparatus according to the present invention includes an ultrasonic sensor that is a contact-type ultrasonic probe that detects an reflected wave by transmitting an ultrasonic wave to the spot welded portion, and the ultrasonic sensor is provided on an arm. And the robot moves the position of the ultrasonic sensor with respect to one spot weld by scanning in a plurality of directions while the ultrasonic sensor is in contact with the workpiece surface by the robot. a robot controller for controlling the operation, prior SL receives the intensity of the reflected waves from said ultrasonic sensor which receives the position of the ultrasonic sensor from the robot controller, which is detected at a plurality of points of said spot welds the intensity of the reflected wave is distributed on the position coordinates, and a data processing apparatus for performing a quality check of the spot weld on the basis of the intensity distribution of the reflected wave, said de Data processing apparatus, based on the after correcting the position coordinates of the reflected wave strength using the deflection amount of each scanning direction caused by the load due to friction with the workpiece during the scanning of the ultrasonic sensor to the intensity distribution of the reflected wave Then, the quality of the spot welded portion is confirmed, and the quality judgment result is output.

In this case, when the scanning direction of the ultrasonic sensor is a plurality of directions, a correct distribution cannot be obtained as it is because the direction of bending caused by a load caused by friction with the workpiece is different when scanning the ultrasonic sensor. However, since the position coordinates of the reflected wave intensity are corrected in consideration of the deflection amount for each scanning direction, the correct intensity distribution of the reflected wave can be obtained, and pass / fail judgment based on the intensity distribution state of the reflected wave The accuracy of will be improved dramatically.

As is clear from the above description, according to the present invention, the position coordinates of the reflected wave intensity are corrected in consideration of the amount of deflection in each scanning direction, so that the correct intensity distribution of the reflected wave can be obtained, and the intensity The accuracy of pass / fail judgment based on the distribution state is dramatically improved.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention or reference invention will be described with reference to the drawings.

(First embodiment)
Figure 1 is a block diagram showing an inspection apparatus 10 of the spot welds of the first embodiment according to the reference invention. As shown in FIG. 1, the spot welded portion inspection apparatus 10 includes an ultrasonic sensor 11 that transmits an ultrasonic wave to a spot welded portion SP on an installed workpiece W to detect a reflected wave. The ultrasonic sensor 11 is attached to the arm tip 12 a of the articulated robot 12. A visual sensor 16 for photographing the workpiece W is also attached to the arm tip 12a of the robot 12. The robot 12 is connected to a robot controller 13 that drives and controls the robot 12 so as to move the position and posture of the arm tip 12a.

  An ultrasonic inspection device 15 is connected to the ultrasonic sensor 11 via a relay amplifier 14 that amplifies the output voltage from the ultrasonic sensor 11. The ultrasonic inspection apparatus 15 is configured to determine whether the spot welded portion SP on the workpiece W is good or bad based on measurement data from the ultrasonic sensor 11. The visual sensor 16 can detect the position of the spot welded portion SP and the orientation of the surface (for example, the perpendicular direction) by performing a known image processing technique on the image received from the visual sensor 16. 17 is connected. A data processing device 18 is connected to the robot controller 13, the ultrasonic inspection device 15, and the image processing device 17.

  The data processing device 18 receives the posture and position of the ultrasonic sensor 11 from the robot controller 13 and also receives measurement data and pass / fail judgment results from the ultrasonic inspection device 15, and sends the posture, position, measurement data, and pass / fail judgment results. They are stored in a storage unit (not shown) in association with each other. Further, the data processing device 18 outputs an operation command to the robot controller 13 in accordance with the measurement data received from the ultrasonic inspection device 15. Further, the data processing device 18 detects the posture and position where the intensity of the reflected wave of the ultrasonic sensor 11 is maximized, and outputs a pass / fail judgment result at the posture and position to a display device (not shown). Further, the data processing device 18 receives the position and the perpendicular direction of the spot welded portion SP on the workpiece W from the image processing device 17 and outputs an operation command to the robot controller 13.

  FIG. 2 is an enlarged view of a main part showing the ultrasonic sensor 11 and the visual sensor 16 of the inspection apparatus 10 shown in FIG. As shown in FIG. 2, an ultrasonic sensor 24 is attached to the arm distal end portion 12 a via a first bracket 20 and a second bracket 23. A flange portion 12b is provided on the distal end surface of the arm distal end portion 12a. The first bracket 20 has flange portions 20b and 20c at both ends of the shaft portion 20a. One flange portion 20b is fixed to the flange portion 12b of the arm distal end portion 12a with a bolt 21. A bottom wall portion 22a of an L-shaped second bracket 22 is fixed to the other flange portion 20c of the first bracket 20 with a bolt 23 in a front view. The ultrasonic sensor 11 is fixed to the lower surface of the bottom surface portion 22 a of the second bracket 22.

  The ultrasonic sensor 11 is a contact-type ultrasonic probe, and a sensing unit 11a that transmits an ultrasonic wave and receives a reflected wave is provided at the tip thereof. A connector portion 11b for connecting a wiring cable is provided on the side surface of the ultrasonic sensor 11, and a spring 24 for absorbing a load on the sensing portion 11a is provided on the upper portion. The visual sensor 16 is fixed to the side wall portion 22b of the second bracket 22 with bolts 28 so as to face substantially the same direction as the ultrasonic sensor 11. As the visual sensor 16, a CCD camera 25 having a lens 26 at the tip is used. Note that the first bracket 20 may be eliminated and the second bracket 22 may be directly attached to the arm tip 12a.

  FIG. 3 is a flowchart for explaining the operation of the inspection apparatus 10 shown in FIG. The operation of the spot welded portion inspection apparatus 10 will be described below mainly based on FIG. As shown in FIGS. 1 and 3, first, the image processing device 17 analyzes the image obtained by the visual sensor 16 by a known image processing technique, and the position of the spot welded portion SP on the workpiece W and its perpendicular direction. (A direction perpendicular to the surface) is detected (step S1). The data processing device 18 receives data relating to the detection position and the perpendicular direction from the image processing device 17, the ultrasonic sensor 11 is in contact with the vicinity of the center of the spot weld SP, and the ultrasonic sensor 11 is in the spot weld. For example, the robot controller 13 is instructed to be perpendicular to the surface of the SP, and the initial position and initial posture of the ultrasonic sensor 11 are determined (step S2).

  FIG. 4A is a cross-sectional view for explaining the inspection by the ultrasonic sensor 11, and FIG. 4B is a graph showing the intensity of the reflected wave detected by the ultrasonic sensor 11. As shown in FIG. 4A, the workpiece W is spot-welded with the upper metal plate Wa and the lower metal plate Wb overlapped, and a nugget N is formed inside the spot welded portion SP. . While the axis 12 of the ultrasonic sensor 11 is tilted by the robot 12 from the initial position and the initial posture, the ultrasonic sensor 11 transmits ultrasonic waves to one point on the spot weld SP. That is, only the posture is changed around the initial posture without changing the position of the sensing unit 11a of the ultrasonic sensor 11 with respect to the workpiece W.

  The data processing device 18 refers to the reflected wave data received from the ultrasonic sensor 11 via the ultrasonic inspection device 15 and the attitude data of the ultrasonic sensor 11 received from the robot controller 13, and the ultrasonic sensor 11. Detects the optimum posture at which the intensity of the first reflected bottom surface wave received by is maximized (step S3). Here, the bottom first reflected wave is first received in time among the reflected waves reflected by the bottom surface of the lower metal plate Wb (surface opposite to the ultrasonic sensor 11) and received by the ultrasonic sensor 11. It is a wave, which is the signal at the portion indicated by A in FIG. In the present embodiment, the bottom first reflected wave is used for the determination, but the average intensity of the reflected wave may be used, or another reflected wave such as the bottom second reflected wave may be used.

  FIG. 5 is a perspective view for explaining scanning of the ultrasonic sensor 11. Next, as shown in FIG. 5, the data processing device 18 instructs the robot controller 13 to maintain the optimum posture in which the bottom first reflected wave is maximized (for example, the workpiece surface shape (or workpiece coordinate system)). In the state in which the direction of the axis X with respect to is fixed), the ultrasonic sensor 11 scans the center of the spot weld SP and its vicinity by moving the ultrasonic sensor 11 along a predetermined path while being in contact with the workpiece W. . The data processing device 18 refers to the reflected wave data received from the ultrasonic sensor 11 via the ultrasonic inspection device 15 and the position data of the ultrasonic sensor 11 received from the robot controller 13, and the ultrasonic sensor 11. The optimum position at which the intensity of the bottom first reflected wave received by is maximized is detected (step S4). The amount of bending of the ultrasonic sensor 11 due to friction with the workpiece W of the ultrasonic sensor 11 is input to the data processing device 18 after being inspected in advance using a test piece having a known nugget shape. The apparatus 18 corrects the position of the ultrasonic sensor 11 using the amount of bending with respect to the position information received from the robot controller 13.

  Then, the data processing device 18 receives the result of the pass / fail determination using the measurement data of the ultrasonic sensor 11 at the detected optimum posture and optimum position from the ultrasonic inspection device 15 and outputs it to a display device (not shown) or the like. (Step S5). Here, as shown in FIG. 6, since the welding state of the spot welded portion can be grasped by the intensity pattern of the reflected wave, the pass / fail judgment of the spot welded portion is performed by analyzing the intensity pattern of the reflected wave. Yes.

  Next, it is determined whether or not there is a spot welded portion to be inspected next on the workpiece W. If it exists, the process returns to step S1, and if not, the process ends (step S6).

  With the above configuration, a plurality of postures and positions of the ultrasonic sensor 11 are tested for one spot welded portion SP, and the posture and position where the intensity of the bottom first reflected wave is maximum among the plurality of postures and positions are finalized. Therefore, the quality of the spot welded portion SP can be determined with the best inspection posture and inspection position at all times.

  In addition, after detecting the optimum posture of the ultrasonic sensor with the position of the ultrasonic sensor being stationary at one point of the spot welded portion, the optimum position is determined by scanning the ultrasonic sensor while maintaining the optimum posture. As a result, the time required to detect the optimum posture and the optimum position can be minimized. That is, the amount of change in the posture and position of the ultrasonic sensor 11 can be efficiently suppressed while exhaustively trying the posture and position of the ultrasonic sensor 11, and the inspection time can be effectively shortened.

(Second Embodiment)
Next, a second embodiment according to the reference invention will be described. FIG. 7 is a flowchart for explaining the operation of the inspection apparatus for spot welds according to the second embodiment. In FIG. 7, the same steps as those in the first embodiment are denoted by the same reference numerals.

  As shown in FIG. 7, steps S1 to S4 are the same as those in the first embodiment, and a description thereof will be omitted. After the optimum position is detected in step S4, ultrasonic waves are transmitted while the ultrasonic sensor 11 is further tilted at a preset angle by the robot 12 at the optimum position. That is, only the posture is changed without changing the contact position of the sensing unit 11a of the ultrasonic sensor 11 with the workpiece W. The data processing device 18 refers to the reflected wave data received from the ultrasonic sensor 11 via the ultrasonic inspection device 15 and the attitude data of the ultrasonic sensor 11 received from the robot controller 13, and the ultrasonic sensor 11. Detects the posture in which the intensity of the bottom first reflected wave received is maximum and updates the optimum posture (step S7).

  Next, the data processing device 18 receives the result of the pass / fail determination using the measurement data of the ultrasonic sensor 11 at the optimal position and the updated optimal posture from the ultrasonic inspection device 15 and outputs the result to a display device or the like (not shown). (Step S8). Next, it is determined whether or not there is a spot welded portion to be inspected next on the workpiece W. If it exists, the process returns to step S1, and if not, the process ends (step S9).

  With the above configuration, the optimum position is updated by scanning the ultrasonic sensor while maintaining the optimum position detected at the initial position, and then changing the position of the ultrasonic sensor to update the optimum position. . Therefore, the detection accuracy of the optimum posture and position is improved, and the reliability of the pass / fail determination can be improved. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

(Third embodiment)
Next, a third embodiment according to the present invention will be described. FIG. 8 is a flowchart for explaining the operation of the spot welded inspection apparatus according to the third embodiment. In FIG. 8, the same steps as those in the first embodiment are denoted by the same reference numerals.

  As shown in FIG. 8, steps S1 to S5 are the same as those in the first embodiment, and a description thereof will be omitted. After the quality determination of the spot weld is performed in step S5, the data processing device 18 creates a distribution map of the bottom first reflected wave of the measurement data acquired while scanning the ultrasonic sensor 11 (step S10).

  FIG. 9 is a screen 30 that displays a distribution diagram in which the bottom first reflected wave detected by continuously scanning the ultrasonic sensor 11 is plotted on the position coordinates. The plot on the screen 30 expresses the intensity of the bottom first reflected wave by color. As shown in FIG. 9, the robot 12 scans the ultrasonic sensor 11 in a zig-zag manner near the center of the spot weld SP so that the scanning direction is two directions, and the ultrasonic inspection device 15 measures measurement data at a predetermined timing. Sampling. Note that FIG. 9 is an example, and it is more preferable to perform sampling at a high resolution by narrowing the plot interval on the position coordinates.

  FIG. 10 shows a screen 31 in which the plot of FIG. 9 is interpolated without correcting the deflection and the distribution map is displayed in gradation. The ultrasonic sensor 11 is bent by a load caused by friction with the workpiece W during scanning. However, when the ultrasonic sensor 11 is scanned zigzag as shown in FIG. 9, the bending direction is two directions. If it is as it is, it will be displayed in a distorted shape by mistake as shown in FIG. Therefore, in this embodiment, a correct distribution map can be obtained by correcting using the deflection amount for each scanning direction.

  FIG. 11 shows a screen 32 on which a distribution map is displayed in gradation by correcting the deflection and interpolating the plot of FIG. A test inspection is carried out before the main inspection, and in order to display a correct distribution map at the time of the test inspection, the amount of deflection to be corrected is confirmed in advance and input to the data processing device 18. deep. Then, the position coordinates of the measurement data detected in the other scanning direction are corrected so as to match the position coordinates of the measurement data detected in one scanning direction of the zigzag, and the deflection correction as shown in the screen 32 in FIG. Create a later distribution map. As shown in FIG. 12, when the ultrasonic sensor 11 is scanned only in one direction, the amount of deflection is uniform and the intensity distribution shape is displayed correctly, but the position is unidirectional by the amount of deflection. In this case, it is preferable to correct the deflection because of the deviation.

  Then, the data processing device 18 performs further pass / fail confirmation based on the intensity distribution state of the distribution chart shown in FIG. 11 (for example, the intensity distribution shape, the number of specific intensity regions, the area of the high intensity region, etc.) (step S11). For example, as shown in FIG. 11, the data processing apparatus 18 has a single high-strength region, is relatively close to a circular shape, and the spot-welded portion is good when the high-strength region has a certain area or more. Is determined. On the other hand, as shown in the distribution diagram of FIG. 13, when the high intensity region of the bottom first reflected wave is divided into two, it is determined that there is a possibility that the reflected wave of the nugget is not accurately captured.

  With the above configuration, since the quality determination is performed based on the measurement data of the ultrasonic sensor 11 in the optimum posture and position, and further quality determination is performed based on the intensity distribution state of the distribution map. The accuracy of pass / fail judgment is dramatically improved. Since other configurations are the same as those of the first embodiment, description thereof is omitted. In the present embodiment, the quality of the distribution map is automatically confirmed by the data processing device 18, but the displayed distribution map may be visually confirmed by a person.

(Fourth embodiment)
Next, a fourth embodiment according to the reference invention will be described. FIG. 14 is a flowchart for explaining the operation of the spot welded portion inspection apparatus according to the fourth embodiment. As shown in FIG. 14, first, the image processing device 17 analyzes the image obtained by the visual sensor 16 using a known image processing technique to detect the position and the perpendicular direction of the spot welded portion SP on the workpiece W (step S20).

  The data processing device 18 receives data relating to the detection position and the direction perpendicular to the image processing device 17, and the ultrasonic sensor 11 is in contact with a certain point near the center position of the spot weld SP. The robot controller 13 is instructed to change only the posture. The data processing device 18 refers to the reflected wave data received from the ultrasonic sensor 11 via the ultrasonic inspection device 15 and the attitude data of the ultrasonic sensor 11 received from the robot controller 13, and the ultrasonic sensor 11. Detects the optimum posture at which the intensity of the first reflected bottom surface wave received is maximum (step S21). Then, the ultrasonic inspection device 15 determines the quality of the spot welded portion with the measurement data of the ultrasonic sensor 11 in the optimum posture, and stores the measurement data and the quality determination result in the storage unit of the data processing device 18 (step S22). . At that time, the data processing device 18 stores the measurement data and the pass / fail judgment result in association with the position and posture received from the robot controller 13.

  Next, the data processing device 18 determines whether a plurality of preset measurement points have been sampled (step S23). Since only one point has been sampled here, the data processing apparatus 18 moves the ultrasonic sensor 11 on the spot welded portion by a predetermined amount, and similarly changes only the attitude of the ultrasonic sensor 11 at the next measurement point. The robot controller 13 is instructed to do so. The data processing device 18 refers to the reflected wave data received from the ultrasonic sensor 11 via the ultrasonic inspection device 15 and the attitude data of the ultrasonic sensor 11 received from the robot controller 13, and the ultrasonic sensor 11. Detects the optimum posture at which the intensity of the bottom surface first reflected wave received is maximized (step S24). Then, the ultrasonic inspection device 15 determines the quality of the spot welded portion with the measurement data of the ultrasonic sensor 11 in the optimum posture, and stores the measurement data and the quality determination result in the storage unit of the data processing device 18 (step S22). .

  If such an operation is repeated and the data processing device 18 determines that a plurality of preset measurement points have been sampled (step S23), the respective measurement data at all measurement points near the center position of the spot welded portion. And the quality determination is performed comprehensively based on the quality determination result (step S25). Next, it is determined whether or not there is a spot welded portion to be inspected next on the workpiece W. If it exists, the process returns to step S20, and if not, the process ends (step S26). Since other configurations are the same as those of the first embodiment, description thereof is omitted.

(Fifth embodiment)
Next, a fifth embodiment according to the reference invention will be described. FIG. 15 is a flowchart for explaining the operation of the spot welded portion inspection apparatus according to the fifth embodiment. In FIG. 15, the same steps as those in the first embodiment are denoted by the same reference numerals. As shown in FIG. 15, when continuously inspecting a plurality of workpieces W, the data processing apparatus 18 already has the optimal posture and the optimal position of the ultrasonic sensor 11 used for the pass / fail determination at the time of the previous workpiece inspection. It is determined whether or not (step S30). If there is an optimum posture and optimum position at the time of the previous workpiece inspection, the data processing device 18 adopts them as the initial posture and initial position of the ultrasonic sensor 11 at the time of the current workpiece inspection (step S31).

  On the other hand, when the first workpiece W is inspected, there is no posture and position data at the time of the previous inspection, so the image processing device 17 analyzes the image obtained by the visual sensor 16 using a known image processing technique. Then, the position and the direction perpendicular to the spot weld SP on the workpiece W are detected (step S32). The data processing device 18 receives data relating to the detection position and the perpendicular direction from the image processing device 17, the ultrasonic sensor 11 is in contact with the vicinity of the center of the spot weld SP, and the ultrasonic sensor 11 is in the spot weld. For example, the robot controller 13 is instructed to be perpendicular to the surface of the SP, and the initial position and initial posture of the ultrasonic sensor 11 are determined (step S31). Subsequent steps S3 to S6 are the same as in the first embodiment.

  With the above configuration, when a plurality of workpieces W are continuously inspected, the locations of the spot welds SP are substantially the same, and the posture and position of the ultrasonic sensor 11 used for the pass / fail judgment at the previous inspection are inspected this time. Therefore, the accuracy of the initial posture and the initial position with respect to the spot welded portion SP of the ultrasonic sensor 11 is improved. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

(Sixth embodiment)
Next, a sixth embodiment according to the reference invention will be described. FIG. 16 is a flowchart for explaining the operation of the spot welded inspection apparatus according to the sixth embodiment. As shown in FIG. 16, steps S1 and S2 are the same as those in the first embodiment, and thus description thereof is omitted. The robot 12 scans the center of the spot weld SP and the vicinity thereof by changing only the position of the ultrasonic sensor 11 while maintaining the attitude of the ultrasonic sensor 11 from the initial position and initial attitude determined in step S2. . The data processing device 18 refers to the reflected wave data received from the ultrasonic sensor 11 via the ultrasonic inspection device 15 and the position data of the ultrasonic sensor 11 received from the robot controller 13, and the ultrasonic sensor 11. The optimum position at which the intensity of the bottom first reflected wave received by is maximized is detected (step S40).

  Next, the data processing device 18 instructs the robot controller 13 to change only the posture of the ultrasonic sensor 11 while maintaining the optimum position where the bottom first reflected wave is maximized. With reference to the reflected wave data received via the ultrasonic inspection apparatus 15 and the attitude data of the ultrasonic sensor 11 received from the robot controller 13, the intensity of the bottom first reflected wave received by the ultrasonic sensor 11 is maximum. An optimal posture is detected (step S41).

  Then, the data processing device 18 receives the result of the pass / fail determination using the measurement data of the ultrasonic sensor 11 at the detected optimal position and optimal posture from the ultrasonic inspection device 15 and outputs it to a display device (not shown) or the like. (Step S42). Next, it is determined whether or not there is a spot welded portion to be inspected next on the workpiece W. If it exists, the process returns to step S1, and if not, the process ends (step S43). Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  In each embodiment described above, the workpiece W is fixed and the ultrasonic sensor 11 is moved, but conversely, the ultrasonic sensor 11 may be fixed and the workpiece W may be moved by a robot.

Thus, inspection method and apparatus of the spot-welded portion according to the present invention has an excellent effect that it is possible to highly accurate quality determination of spot weld, the inspection apparatus of such spot welds It is beneficial to apply.

It is a block diagram which shows the inspection apparatus of the spot weld part which concerns on 1st Embodiment which concerns on a reference invention . It is a principal part enlarged view showing the ultrasonic sensor and visual sensor of the test | inspection apparatus shown in FIG. It is a flowchart explaining operation | movement of the test | inspection apparatus shown in FIG. (A) is sectional drawing explaining the test | inspection by an ultrasonic sensor, (b) is a graph showing the intensity | strength of the reflected wave detected by an ultrasonic sensor. It is a perspective view explaining the scanning of an ultrasonic sensor. It is a list figure which shows the criteria of a quality determination of a spot weld part. It is a flowchart explaining operation | movement of the inspection apparatus of the spot weld part which concerns on 2nd Embodiment which concerns on a reference invention . It is a flowchart explaining operation | movement of the inspection apparatus of the spot weld part which concerns on 3rd Embodiment which concerns on this invention . FIG. 9 is a distribution diagram in which bottom first reflected waves detected by continuously scanning the ultrasonic sensor of the inspection apparatus of FIG. 8 are plotted on position coordinates. FIG. 10 is a distribution diagram in which the plot of FIG. 9 is interpolated and displayed in a gradation without deflection correction. FIG. 10 is a distribution diagram in which gradation correction is performed by performing deflection correction and interpolating the plot of FIG. 9. It is the distribution map which plotted the bottom face 1st reflected wave detected by scanning an ultrasonic sensor in one direction on a position coordinate. It is a distribution map which shows the example of abnormal distribution. It is a flowchart explaining operation | movement of the inspection apparatus of the spot weld part which concerns on 4th Embodiment which concerns on reference invention . It is a flowchart explaining operation | movement of the inspection apparatus of the spot weld part which concerns on 5th Embodiment which concerns on reference invention . It is a flowchart explaining operation | movement of the inspection apparatus of the spot weld part which concerns on 6th Embodiment which concerns on reference invention .

DESCRIPTION OF SYMBOLS 10 Spot welding part inspection apparatus 11 Ultrasonic sensor 12 Robot 13 Robot controller 15 Ultrasonic inspection apparatus 16 Visual sensor 18 Data processing apparatus SP Spot welding part W Workpiece

Claims (10)

The robot scans the ultrasonic sensor, which is a contact-type ultrasonic probe , in contact with the workpiece surface in a plurality of directions to change the position of the ultrasonic sensor with respect to the workpiece, thereby forming a single spot weld. In contrast, ultrasonic waves are transmitted at multiple locations,
The intensity of reflected waves detected at a plurality of points in the spot welded portion is distributed on the position coordinates by a data processing device, and the data processing device is subjected to a load caused by friction with a workpiece during scanning of the ultrasonic sensor. the position coordinates of the reflected wave intensity is corrected using the amount of deflection of each resulting scanning direction, spot weld the quality check of the spot weld, characterized in row Ukoto based on the intensity distribution of the reflected wave Inspection method. The data processing device creates a distribution map that displays the intensity of the reflected wave on position coordinates, and confirms the quality of the spot weld based on the intensity distribution state of the distribution map. The inspection method of the spot-welded part as described in 1 . While detecting the position where the intensity of the reflected wave is the maximum among the plurality of positions, and correcting the position using the amount of bending caused by the load caused by friction with the workpiece during scanning of the ultrasonic sensor,
The detected inspection method of spot welds according to claim 1 or 2 using the measurement data of the ultrasonic sensor at the position, characterized by further performing quality determination of the spot welds. The posture of the ultrasonic sensor with respect to the workpiece is also changed by the robot, and ultrasonic waves are transmitted in a plurality of postures to one spot welded portion, and the posture in which the intensity of the reflected wave is maximum among the plurality of postures and positions, and Detect the position,
The spot welded portion inspection method according to any one of claims 1 to 3 , wherein the spot welded portion is judged to be good or bad using measurement data of the ultrasonic sensor in the detected posture and position. While changing the posture of the ultrasonic sensor with respect to the workpiece by the robot, the ultrasonic sensor transmits an ultrasonic wave to one point of the spot welded portion to detect the optimum posture in which the intensity of the reflected wave is maximized,
Optimum intensity of reflected wave is maximized by scanning the spot weld with the ultrasonic sensor by moving the ultrasonic sensor relative to the workpiece with the robot while maintaining the optimal posture. Detect the position,
The spot welded portion inspection method according to claim 4 , wherein the spot welded portion is determined to be good or bad using measurement data of the ultrasonic sensor at the optimal posture and the optimal position. While changing the posture of the ultrasonic sensor with respect to the workpiece by the robot, the ultrasonic sensor transmits an ultrasonic wave to one point of the spot welded portion to detect the posture where the intensity of the reflected wave is maximized,
By moving the ultrasonic sensor relative to the workpiece by the robot while the detected posture is maintained, the spot welded portion is scanned by the ultrasonic sensor and the intensity of the reflected wave is maximized. To detect the optimal position
While changing the posture of the ultrasonic sensor with respect to the workpiece by the robot at the optimum position, an ultrasonic wave is transmitted by the ultrasonic sensor to detect the optimum posture where the intensity of the reflected wave is maximized,
The spot welded portion inspection method according to claim 4 , wherein the spot welded portion is determined to be good or bad using measurement data of the ultrasonic sensor at the optimal posture and the optimal position. The visual sensor detecting the position of the spot weld on the work, according to any one of claims 1 to 6, wherein determining the initial position of the ultrasonic sensor based on the detected position Inspection method for spot welds. The visual sensor detects the orientation of the surface of the spot weld portion on the workpiece, in any one of claims 1 to 7, wherein the determining the initial attitude of the ultrasonic sensor based on the orientation of the surface Inspection method of the spot welding part of description. When the continuous inspected plurality of workpieces, said of claims 1 to 8, characterized by using the optimum posture and the optimum position of the ultrasonic sensor as the initial orientation and position of this test using the quality determination in the previous test The inspection method of the spot welding part in any one. An ultrasonic sensor that is a contact-type ultrasonic probe that detects reflected waves by transmitting ultrasonic waves to a spot weld;
A robot provided with the ultrasonic sensor on the arm;
A robot that controls the operation of the robot so as to change the position of the ultrasonic sensor with respect to one spot weld by scanning the ultrasonic sensor in a plurality of directions while the ultrasonic sensor is in contact with the workpiece surface by the robot. A controller,
Said ultrasound receiving the intensity of the reflected wave from the sensor, the position coordinates of the intensity of the reflected wave detected at a plurality of points of said spot welds which receives the position of the ultrasonic sensor from the previous SL robot controller And a data processing device for confirming the quality of the spot weld based on the intensity distribution state of the reflected wave ,
The data processing device corrects the position coordinates of the reflected wave intensity using a deflection amount for each scanning direction caused by a load caused by friction with a workpiece during scanning of the ultrasonic sensor, and then changes the reflected wave intensity distribution state. An inspection apparatus for a spot welded portion that performs pass / fail confirmation of the spot welded portion based on the result and outputs the pass / fail judgment result.

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