JP2014238387A - Welding quality inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding quality inspection device capable of accurately determining welding quality in a welding place (a welding ball) where end parts of a segment coil arranged in a stator core are welded to each other.SOLUTION: A welding quality inspection device 1 inspecting welding quality in an abutting part 28 where straight angle coil lines 26 arranged in a slot of a stator core 22 are welded to each other includes: a camera 10 imaging the abutting part 28; a while LED 12 irradiating the abutting part 28 with while illumination; blue LEDs 14A, 14B irradiating the abutting part 28 with illumination having a color having the complementary color relation with the color of the straight angle coil line 26 in a direction different from the irradiation direction of the while LED 12; and a calculation part 16 calculating a joint length L to determine welding quality on the basis of imaging data acquired by the camera 10.

Description

  The present invention relates to a welding quality inspection apparatus for inspecting the welding quality of a welded portion where end portions of segment coils provided in a motor used in a hybrid vehicle or an electric vehicle are welded to each other.

  In recent years, motors used in hybrid vehicles and electric vehicles have been pursued to improve the output performance of motors. For example, a segment core having a rectangular cross section (flat coil wire) is used to form a stator core. There is something. As this type of stator, for example, a pair of segment coils configured in a U shape by a pair of straight portions and a connecting portion are mounted in a slot of the stator core and protrude to the opposite side of the connecting portion arrangement side. The tip of the straight line portion is twisted in the circumferential direction and welded to the straight line portion twisted in the circumferential direction of the other segment coil.

  Here, a motor used in a hybrid vehicle or an electric vehicle requires a high output. For this reason, it is very important to ensure the quality of the welded portion (welded ball) where the end portions of the segment coil are welded together. This is because if the quality of the weld ball is poor (welding failure occurs), the portion becomes a large electric resistance, causing a decrease in current or heat generation, leading to a decrease in output of the motor.

  As a technique for ensuring the quality of a welded portion (welded ball) in which end portions of segment coils are welded together, for example, there is a method described in Patent Document 1. In the technique described here, light is irradiated to the welded part from the direction that forms a predetermined angle with respect to the end face of the stator core by ring illumination, and an image of the welded part is acquired by the CCD camera, and the center position of the acquired image On the basis of the penetration correlation amount calculated in (1), unwelded, melted, and insufficiently melted welds are detected.

JP 2006-021214 A

  However, in the above technique, when the welded portion (welded ball) where the ends of the segment coils are welded is imaged, the welding ball is illuminated from the direction coaxial with the camera. There is a problem that it may be affected by the reflected light from the surface of the welding ball or the surface of the weld ball. That is, there is a case where the image of the weld ball cannot be obtained accurately. In such a case, the welding quality in the weld ball could not be determined with high accuracy.

  Therefore, the present invention has been made to solve the above-described problems, and it is possible to accurately determine the welding quality at a welding location (welding ball) in which end portions of segment coils arranged on the stator core are welded to each other. An object of the present invention is to provide a welding quality inspection apparatus capable of performing the above.

  One aspect of the present invention made in order to solve the above-described problems is an image pickup for picking up an image of the welded portion in a welding quality inspection device for inspecting the weld quality at the welded portion where the segment coils arranged in the slots of the stator core are welded together. And a color of the segment coil and a complementary color relationship from a direction different from the irradiation direction of the first light source, and a first light source that irradiates the welding portion with the same color or substantially the same color illumination as the segment coil A second light source that irradiates the welding spot with the illumination of a certain color, and a calculation unit that calculates the various dimensions of the welding spot and determines the welding quality based on the imaging data acquired by the imaging unit. It is characterized by.

  According to this aspect, when imaging the welding location, the first light source emits white illumination or illumination of the same color or substantially the same color as the segment coil, and the second light source emits the segment coil in the color correlation. Illumination of a color complementary to the color is applied to the welded part. Here, by the illumination from the second light source, the outline (outer shape) of the weld ball at the welded portion can be clearly raised. Thereby, the imaging part can acquire the image of a welding ball correctly and stably, without receiving the influence of the reflected light from a background (end surface of a stator core, etc.) or a welding ball surface. Therefore, as a result of being able to accurately calculate various dimensions of the welding location in the calculation unit, it is possible to accurately determine the welding quality. In addition, as a dimension of the welding location to calculate, the welding length and penetration depth of a welding ball can be mentioned, for example.

  In the above aspect, the imaging unit is disposed in a direction orthogonal to the end face of the stator core, and the first light source is a light source that irradiates the welding spot with white illumination, and the irradiation direction of the imaging unit is The second light source is arranged so as to be in the same direction as the imaging direction, and the second light source has the imaging direction of the imaging unit as a boundary so that the irradiation direction forms a preset inclination angle with respect to the imaging direction of the imaging unit. It is preferable that they are arranged symmetrically.

  According to this aspect, it is possible to brightly illuminate the entire imaging range of the imaging unit with the first light source, and it is possible to make the outline of the weld ball emerge from blue to blue-green in the color correlation by the second light source. As a result, an image of the weld ball can be acquired accurately and stably.

  In said aspect, it is preferable that the inclination-angle of the said 2nd light source is set within the range of 40 degrees-120 degrees, and -40 degrees--120 degrees.

  According to this aspect, the illumination from the second light source is also irradiated below the weld ball (portion on the stator core side). Furthermore, the illumination from the second light source is applied to the welding ball without obstructing the segment coils arranged in the adjacent slots (without causing shadow reflection or the like). In this way, the illumination of the second light source is reliably applied to the entire weld ball that is the inspection target.

  In said aspect, it is preferable that the said calculating part calculates the joining length by extracting the outline of the welding ball in the said welding location from the imaging data acquired by the said imaging part.

  According to this aspect, the outline of the weld ball can be accurately extracted from the image of the weld ball accurately acquired as described above, and the joining length is accurately calculated from the extracted data of the outline of the weld ball. be able to.

  In the above aspect, the imaging unit is disposed so as to have a preset inclination angle with respect to a direction orthogonal to the end face of the stator core, and the first light source irradiates the welding spot with white illumination. The light source is disposed on the side opposite to the imaging unit with the segment coil to be imaged as a boundary so as to form an inclination angle set in advance with respect to the axial direction of the stator core, and the second light source is It is preferable that they are arranged on the same side as the imaging unit with the segment coil to be imaged as a boundary so as to form a preset tilt angle with respect to the axial direction of the stator core.

  According to this aspect, the illumination from the first light source is reflected by the welding ball and incident on the imaging unit, and the second light source changes the contour of the welding ball and the segment coil peeling portion from blue to blue in color correlation. It can appear in green. As a result, an image of the weld ball can be acquired accurately and stably.

  In the above aspect, an inclination angle of the imaging unit is set within a range of 10 ° to 50 °, an inclination angle of the first light source is set within a range of −10 ° to −70 °, It is preferable that the tilt angle of the second light source is set within a range of 40 ° to 120 °, and the tilt angle of the second light source is larger than the tilt angle of the imaging unit.

  According to this aspect, the illumination from the first light source is applied to the tip of the weld ball. Further, illumination from the second light source is applied to the outer peripheral portion of the weld ball and the peeled portion of the segment coil. Furthermore, the illumination from the second light source is applied to the welding ball without disturbing the segment coils arranged in the adjacent slots (no shadows appear). In this way, the illumination of the first light source and the second light source is reliably applied to the entire weld ball that is the inspection target. And since it becomes possible to make the regular reflection light of the illumination from a 1st light source inject into an imaging part via a welding ball, the outline of the front-end | tip part of a welding ball can be extracted reliably by an imaging part.

  In said aspect, it is preferable that the said calculating part calculates the penetration depth by extracting the outline of the welding ball in the said welding location and the both ends of the said segment coil from the imaging data acquired by the said imaging part.

  According to this aspect, it is possible to accurately extract the contour of the weld ball and both ends of the segment coil from the image of the weld ball accurately acquired as described above, and from the extracted data of the contour of the weld ball and both ends of the segment coil. The penetration depth can be accurately calculated.

  In the above aspect, the imaging unit is disposed in a direction orthogonal to the end surface of the stator core, and the first light source has an irradiation direction inclined with respect to the imaging direction of the imaging unit, The light source irradiates the entire imaging range of the imaging unit with illumination of the same color or substantially the same color, and the second light source has an irradiation angle set in advance with respect to a vertical direction of the imaging direction of the imaging unit In this way, it is preferable that they are arranged symmetrically with respect to the imaging direction of the imaging unit.

  According to this aspect, the outline of the weld ball can be raised from blue to blue-green in the color correlation by the second light source. Moreover, even when the luster of the weld ball is high, the contour of the weld ball can be extracted by the secondary reflected light or diffused light of the illumination of the first light source that reflects or diffuses at the back of the weld ball. . As a result, an image of the weld ball can be acquired accurately and stably.

  In said aspect, it is preferable that the inclination-angle of the said 2nd light source is set within the range of -20 degrees-20 degrees.

  According to this aspect, the outline of the weld ball emerges more effectively from blue to blue-green in the color correlation by the second light source.

  In said aspect, it is preferable that the said calculating part calculates the joining length by extracting the outline of the welding ball in the said welding location from the imaging data acquired by the said imaging part.

  According to this aspect, the outline of the weld ball can be accurately extracted from the image of the weld ball accurately acquired as described above, and the joining length is accurately calculated from the extracted data of the outline of the weld ball. be able to.

  In said aspect, it is preferable that the illumination of the same color as the said segment coil or substantially the same color is red illumination.

  In said aspect, it is preferable that the illumination of the color which has a complementary color relationship with the color of the said segment coil is illumination of the color in any one of blue to blue-green.

  According to the welding quality inspection device of this configuration, it is possible to accurately determine the welding quality at the welding location (welding ball) where the ends of the segment coils arranged on the stator core are welded together.

In Example 1, it is a figure which shows a stator and a welding quality inspection apparatus. FIG. 2 is an enlarged view of a main part of FIG. It is a figure which shows joining length. It is a flowchart figure about the measurement of joining length. It is explanatory drawing regarding the step which extracts the outline of a welding ball. It is explanatory drawing regarding the step which extracts a junction part point. It is explanatory drawing regarding the step which extracts a junction part point. It is explanatory drawing regarding the step which measures joining length. In Example 2, it is a figure which shows a stator and a welding quality inspection apparatus. FIG. 10 is an enlarged view of a main part of FIG. It is a figure which shows the penetration depth. It is a flowchart figure regarding the measurement of a penetration depth. It is explanatory drawing regarding the step which extracts the outline of a welding ball. It is explanatory drawing regarding the step which detects the chamfering part of the peeling part of one flat coil wire. It is explanatory drawing regarding the step which detects the chamfering part of the peeling part of the other rectangular coil wire. It is explanatory drawing regarding the step which detects the intersection of the chamfering part of the peeling part of a flat coil wire, and the outline of a welding ball. It is explanatory drawing regarding the step which detects the midpoint in the clearance gap between two rectangular coil wires. It is explanatory drawing regarding the step which draws a perpendicular. It is explanatory drawing regarding the step which measures the penetration depth. It is a block diagram of the welding quality inspection apparatus of Example 3.

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

[Example 1]
<Configuration of welding quality inspection device>
As shown in FIGS. 1 and 2, the welding quality inspection apparatus 1 of the present embodiment includes a camera 10, a white LED 12, a blue LED 14A, a blue LED 14B, a calculation unit 16, and the like.

  The camera 10 is a CCD camera. The camera 10 is arranged such that its imaging direction (imaging axis 10 a) is perpendicular to the end surface 22 a of the stator core 22 constituting the stator 20 (axial direction of the stator core 22). Here, the imaging axis 10a indicates the imaging direction, and is a line extending from the center point (video center point) of the video generated by the camera 10 in the imaging direction. Then, the camera 10 captures an image of the butt 28 that is a welded portion where a portion of the flat coil wire 26 disposed in a slot (not shown) of the stator core 22 is welded. The camera 10 is an example of the “imaging unit” in the present invention. The flat coil wire 26 is an example of the “segment coil” in the present invention, and a cross section orthogonal to the axial direction is formed in a rectangular shape. The material of the flat coil wire 26 is, for example, copper.

  The white LED 12 is arranged so that the irradiation direction (optical axis) is the same as the imaging direction of the camera 10. Then, the white LED 12 irradiates the abutting unit 28 with white illumination to brighten the entire imaging range of the camera 10. The white LED 12 is an example of the “first light source” in the present invention.

  The blue LED 14A and the blue LED 14B, which are a pair of blue LEDs, have an irradiation direction (optical axis 14Aa and optical axis 14Ba) that forms a predetermined inclination angle θbA and inclination angle θbB set in advance with respect to the imaging direction of the camera 10. Thus, they are arranged symmetrically with the imaging direction of the camera 10 as a boundary. Here, the optical axis 14Aa and the optical axis 14Ba indicate the irradiation direction, and are lines extending in the irradiation direction from the center point of the light emitting surface of the blue LED 14A or the blue LED 14B. Each of the blue LED 14A and the blue LED 14B is an example of the “second light source” in the present invention.

  Here, the inclination angle θbA is desirably set within a range of 40 ° to 120 °. In FIG. 1, as an example, the inclination angle θbA is 60 °. Further, the inclination angle θbB is set within a range of −40 ° to −120 °. In FIG. 1, as an example, the inclination angle θbB is set to −60 °.

  In this way, the blue LED 14A and the blue LED 14B irradiate the butt portion 28 with blue illumination that is complementary to the color of the rectangular coil wire 26 from a direction different from the irradiation direction of the white LED 12. Thereby, since the blue LED 14A and the blue LED 14B can illuminate the welding ball 30 in the butting portion 28 with blue light, as shown in FIG. 5 to be described later, the outline (outside) of the welding ball 30 in the captured image of the camera 10. E1 can be raised.

  In addition, instead of the blue LED 14A and the blue LED 14B, as an illumination of any color from blue to blue-green in the color correlation complementary to the color of the flat coil wire 26, an LED irradiated with blue-green light, or An LED that is irradiated with light of a color between blue and blue-green light in color correlation may be used. Alternatively, instead of using the blue LED 14A or the blue LED 14B, a light source and a filter may be used to realize illumination of any color from blue to blue green in color correlation.

  The calculation unit 16 is configured by a calculation device such as a CPU, and determines the welding quality by calculating various dimensions of the welding ball 30 based on the captured image (imaging data) acquired by the camera 10. For example, as will be described later, the calculation unit 16 extracts the contour E1 of the weld ball 30 in the butt 28 from the captured image acquired by the camera 10, and calculates the joining length L as shown in FIG. Here, the joining length L is a width in a direction along the joining surface of the two flat coil wires 26 when the welding ball 30 is viewed from the upper side.

  For example, the stator 20 twists both ends of a plurality of substantially U-shaped flat coil wires 26 penetrating into the stator core 22 in the circumferential direction of the stator core 22 and welds the tips of adjacent flat coil wires 26 to each other. By doing so, adjacent rectangular coil wires 26 are integrated by the weld balls 30.

<Welding quality inspection method>
Next, a welding quality inspection method using the welding quality inspection apparatus 1 will be described as an operation of the welding quality inspection apparatus 1 having the above-described configuration. Here, the welding quality inspection apparatus 1 calculates the welding length L as shown in FIG. 3 and checks the calculated bonding length L to determine the welding quality at the butt 28. FIG. 4 shows a flowchart regarding the measurement of the joining length L.

  As shown in FIG. 4, first, the detection position of the weld ball 30 is corrected (step S1). Specifically, the position of the weld ball 30 within the imaging range of the camera 10 is confirmed, and the subsequent detection position adjustment of the weld ball 30 is performed.

  Next, the calculating part 16 extracts the outline E1 of the weld ball 30 (step S2). Specifically, as shown in FIG. 5, in the captured image of the camera 10, the outer peripheral part of the weld ball 30 is displayed as a blue part (hatched part in FIG. 5). Therefore, the calculation unit 16 extracts the outer edge portion of the blue portion in the captured image of the camera 10 as the contour E1 of the weld ball 30.

  Next, the arithmetic unit 16 extracts joint points (two points) of the two rectangular coil wires 26 to be joined to each other (step S3).

  Specifically, as illustrated in FIG. 6, the calculation unit 16 draws an edge detection line αe on the edge portion (edge portion) of the weld ball 30 in the captured image of the camera 10. The edge detection line αe is drawn parallel to the longitudinal direction of the cross section of the flat coil wire 26 (the cross section orthogonal to the axial direction of the flat coil wire 26). And the calculating part 16 is the thickness of the flat coil wire 26 (cross section orthogonal to the axial direction in the flat coil wire 26) toward the inner side of the welding ball 30 from the position of the edge detection line αe in the captured image of the camera 10. The joint detection line αs parallel to the edge detection line αe is drawn at a position where the distance corresponding to the size of the width in the short direction is moved.

  Alternatively, as illustrated in FIG. 7, the calculation unit 16 draws the edge detection line αe1 and the edge detection line αe2 on the edge portion (edge) of the weld ball 30 in the captured image of the camera 10. The edge detection line αe1 and the edge detection line αe2 are drawn parallel to the longitudinal direction of the cross section of the flat coil wire 26 (the cross section orthogonal to the axial direction of the flat coil wire 26). Then, the calculation unit 16 draws the joint detection line αs at the midpoint position of the edge detection line αe1 and the edge detection line αe2 in the captured image of the camera 10.

  And the calculating part 16 extracts the intersection P1 and the intersection P2 (joint point) which are the intersections of the outline E1 of the welding ball 30 extracted at step S2 and the joint detection line αs in the captured image of the camera 10. To do.

  Next, the calculating part 16 measures joining length L (step S4). Specifically, as illustrated in FIG. 8, the calculation unit 16 calculates the distance between the intersection point P1 and the intersection point P2 as the joint length L in the captured image of the camera 10. In this way, the calculation unit 16 measures the joining length L. And the calculating part 16 judges welding quality based on the calculated joining length L. FIG.

<Effect of this embodiment>
According to the present embodiment, in the welding quality inspection apparatus 1 that inspects the welding quality in the butt portion 28 in which the rectangular coil wires 26 arranged in the slots of the stator core 22 are welded, the camera 10 that images the butt portion 28, and the white A white LED 12 for illuminating the abutting section 28, a blue LED 14A and a blue LED 14B for illuminating the abutting section 28 with illumination of a color complementary to the color of the flat coil wire 26 from a direction different from the irradiation direction of the white LED 12, And a calculation unit 16 that calculates the welding length L based on the imaging data acquired by the camera 10 and determines the welding quality.

  Thereby, when imaging the abutting portion 28, white illumination is emitted from the white LED 12 to the abutting portion 28, and blue illumination is emitted from the blue LED 14 </ b> A and the blue LED 14 </ b> B to the abutting portion 28. Here, the outline (outer shape) of the weld ball 30 in the butt 28 is clearly raised by illumination from the blue LED 14A and the blue LED 14B which are complementary to the color of the flat coil wire 26 (material is copper, for example). Can do. Thereby, the camera 10 can acquire the image of the welding ball 30 accurately and stably, without being influenced by the background (end surface 22a of the stator core 22, etc.) or the reflected light from the surface of the welding ball 30. Therefore, as a result of the calculation unit 16 being able to accurately calculate the joining length L of the butt 28, the welding quality can be accurately determined.

  Further, the camera 10 is arranged in a direction orthogonal to the end face 22a of the stator core 22. Further, the white LED 12 is arranged so that the irradiation direction is the same as the imaging direction of the camera 10. Furthermore, the blue LED 14A and the blue LED 14B are arranged symmetrically with respect to the imaging direction of the camera 10 so that the irradiation direction forms inclination angles θbA and θbB set in advance with respect to the imaging direction of the camera 10. Thereby, the entire imaging range of the camera 10 can be illuminated brightly by the white LED 12, and the outline of the weld ball 30 can be highlighted in blue by the blue LED 14A and the blue LED 14B. As a result, the image of the weld ball 30 can be acquired accurately and stably.

  Further, the inclination angle θbA is set within a range of 40 ° to 120 °, and the inclination angle θbB is set within a range of −40 ° to −120 °. Thereby, the illumination from the blue LED 14 </ b> A and the blue LED 14 </ b> B is also irradiated below the weld ball 30 (portion on the stator core 22 side). Further, the illumination from the blue LED 14A and the blue LED 14B is applied to the welding ball 30 without obstructing the flat coil wire 26 arranged in the adjacent slot (without causing shadow reflection or the like). In this way, the illumination of the blue LED 14A and the blue LED 14B is reliably irradiated to the entire weld ball 30 to be inspected.

  In addition, the calculation unit 16 calculates the joining length L by extracting the contour E1 of the welding ball 30 in the butt unit 28 from the captured image acquired by the camera 10. As described above, the contour E1 of the weld ball 30 can be accurately extracted from the image of the weld ball 30 that is accurately acquired as described above, and the joining length L is determined from the extracted data of the contour E1 of the weld ball 30. It can be calculated accurately.

[Example 2]
Next, the second embodiment will be described. The same components as those of the first embodiment are denoted by the same reference numerals, the description thereof will be omitted, and different points will be mainly described.

<Configuration of welding quality inspection device>
As shown in FIGS. 9 and 10, the welding quality inspection apparatus 2 of the present embodiment includes a camera 10, a white LED 12, a blue LED 14, a calculation unit 16, and the like.

  The camera 10 is arranged such that its imaging direction (imaging axis 10 a) forms a predetermined inclination angle θc that is set in advance with respect to a direction orthogonal to the end surface 22 a of the stator core 22 that constitutes the stator 20. The camera 10 can acquire images of the butting portions 28 for one row (for example, four) of slots (not shown) in the radial direction of the stator core 22 once or twice.

  Here, it is desirable that the inclination angle θc is set within a range of 10 ° to 50 °. If the inclination angle θc is set larger than 50 °, the penetration amount of the welded portion cannot be accurately detected. On the other hand, if the inclination angle θc is set smaller than 10 °, the adjacent welding portion becomes an obstacle (shadow). This is because the image of the welded portion to be inspected cannot be acquired well. In FIG. 10, as an example, the inclination angle θc is 30 °.

  The irradiation direction (optical axis 12a) of the white LED 12 forms a predetermined inclination angle θw set in advance with respect to the axial direction of the stator core 22 on the opposite side to the camera 10 with respect to the rectangular coil wire 26 to be imaged. Are arranged as follows. More specifically, the white LED 12 is arranged at a position where the specularly reflected light at the butting portion 28 (welded ball 30) of the light emitted from the white LED 12 is incident on the camera 10 with respect to the positional relationship with the camera 10. . The optical axis 12a indicates the irradiation direction, and is a line extending from the center point of the light emitting surface of the white LED 12 in the irradiation direction.

  Here, it is desirable that the inclination angle θw is set within a range of −10 ° to −70 °. In FIG. 10, as an example, the inclination angle θw is −30 °. The white LED 12 irradiates the butt portion 28 with white illumination.

  The blue LED 14 has the same irradiation direction (optical axis 14a) as that of the camera 10 with a rectangular coil wire 26 to be imaged as a boundary so that a predetermined inclination angle θb set in advance with respect to the axial direction of the stator core 22 is formed. Arranged on the side. The optical axis 14a indicates the irradiation direction, and is a line extending in the irradiation direction from the center point of the light emitting surface of the blue LED 14.

  Here, it is desirable that the tilt angle θb is set within a range of 40 ° to 120 ° on the premise that the tilt angle θb is set to be larger than a predetermined tilt angle θc set in advance for the camera 10. In FIG. 10, as an example, the inclination angle θc is 60 °.

  In this way, the blue LED 14 irradiates the butt 28 with blue illumination that is complementary to the color of the flat coil wire 26 from a direction different from the direction of irradiation of the white LED 12. Thereby, since the blue LED 14 can illuminate the outer peripheral part of the welding ball 30 and the peeling part 32 (part from which the coating film has been peeled off) of the flat coil wire 26 with blue light, it will be described later with reference to FIGS. Thus, in the captured image of the camera 10, the outline E2 of the weld ball 30 and the outline of the peeling part 32 can be raised.

<Operation of welding quality inspection device>
Next, a welding quality inspection method using the welding quality inspection apparatus 2 will be described as an operation of the welding quality inspection apparatus 2 having the above-described configuration. Here, the welding quality inspection apparatus 2 calculates the penetration depth D as shown in FIG. 11 and checks the calculated penetration depth D to determine the welding quality at the butt portion 28. Here, the penetration depth D is the axial width of the stator core 22 in the weld ball 30. FIG. 12 is a flowchart regarding the measurement of the penetration depth.

  First, the calculation part 16 corrects the detection position of the weld ball 30 as in step S1 (step S11).

  Next, the calculating part 16 extracts the outline E2 of the weld ball 30 (step S12). Specifically, as illustrated in FIG. 13, the calculation unit 16 extracts the outer peripheral portion of the portion displayed in white as the outline of the tip of the weld ball 30 in the captured image of the camera 10 and floats in blue. The outer peripheral portion of the portion displayed so as to rise (the hatched portion in FIG. 13) is extracted as the contour of the portion other than the tip portion of the weld ball 30. Thereby, as shown in FIG. 13, the calculating part 16 extracts the outline E2 of the welding ball 30.

  Next, the calculating part 16 detects the both ends of the flat coil wire 26 (step S13). Specifically, since the blue LED 14 illuminates the peeling portion 32 of the rectangular coil wire 26 as described above, the outline of the peeling portion 32 appears in blue in the captured image of the camera 10. Therefore, in the captured image of the camera 10, the calculation unit 16 includes a chamfered portion 32 a (see FIG. 14) outside (left side) of the peeling portion 32 of one flat coil wire 26 and a peeling portion 32 of the other flat coil wire 26. The outer (right side) chamfered portion 32b (see FIG. 15) is detected. The chamfered portion 32a and the chamfered portion 32b are examples of “both ends of the segment coil” in the present invention.

  Next, the calculating part 16 detects the intersection of the both ends of the flat coil wire 26, and the outline E2 of the welding ball 30 (step S14). Specifically, as shown in FIG. 16, the calculation unit 16, in the captured image of the camera 10, has an intersection P <b> 11 between the chamfered part 32 a of the peeling part 32 and the contour E <b> 2 of the weld ball 30 and a chamfered part of the peeling part 32. An intersection point P12 between 32b and the contour E2 of the weld ball 30 is detected.

  Next, the computing unit 16 determines whether or not the gap between the two rectangular coil wires 26 can be detected in the captured image of the camera 10 (step S15). Specifically, since the blue LED 14 illuminates the peeling portion 32 of the rectangular coil wire 26 as described above, the outline of the peeling portion 32 appears in blue in the captured image of the camera 10. Therefore, the calculation unit 16 determines whether or not the gap between the peeling portion 32 of one flat coil wire 26 and the peeling portion 32 of the other flat coil wire 26 can be detected in the captured image of the camera 10.

  If the gap between the two rectangular coil wires 26 can be detected in step S15, the arithmetic unit 16 detects the position of the middle point in the gap between the two rectangular coil wires 26 (step S16). Specifically, as shown in FIG. 17, the arithmetic unit 16, in the captured image of the camera 10, is located in the gap between the peeling portion 32 of one flat coil wire 26 and the peeling portion 32 of the other flat coil wire 26. The position of the point is detected, and a midpoint detection line αt is drawn at this midpoint position.

  On the other hand, when the calculation unit 16 cannot detect the gap between the two rectangular coil wires 26 in step S15 (for example, when the peeling portions 32 of the two rectangular coil wires 26 are in contact with each other), the calculation unit 16 and the intersection P11 A midpoint Pc (see FIG. 18) between the intersection points P12 is detected (step S17).

  Next, as shown in FIG. 18, in the captured image of the camera 10, the calculation unit 16 starts from the intersection point P21 between the straight line αp connecting the intersection point P11 and the intersection point P12 and the middle point detection line αt, or from the middle point Pc. Then, a perpendicular line αv is drawn with respect to the straight line αp (step S18).

  Next, the calculating part 16 measures the penetration depth D (step S19). Specifically, as illustrated in FIG. 19, the calculation unit 16 first obtains an intersection P31 between the perpendicular αv and the contour E2 of the weld ball 30 in the captured image of the camera 10. Then, the calculation unit 16 calculates the distance D0 between the intersection P21 (or the middle point Pc) and the intersection P31 in the captured image of the camera 10, and considers the correlation between the distance D0 and the penetration depth D. The penetration depth D is calculated from D0. In this way, the calculation unit 16 measures the penetration depth D. And the calculating part 16 judges welding quality based on the calculated penetration depth D. FIG.

<Effect of this embodiment>
According to the present embodiment, in the welding quality inspection apparatus 2 that inspects the welding quality in the butt portion 28 in which the rectangular coil wires 26 arranged in the slots of the stator core 22 are welded, the camera 10 that images the butt portion 28, and the white In the camera 10, the white LED 12 that irradiates the abutting unit 28 with illumination, the blue LED 14 that irradiates the abutting unit 28 with illumination of a color complementary to the color of the flat coil wire 26 from a direction different from the irradiation direction of the white LED 12, And a calculation unit 16 that calculates the penetration depth D based on the acquired imaging data and determines the welding quality.

  Thereby, when imaging the abutting portion 28, white illumination is emitted from the white LED 12 to the abutting portion 28, and blue illumination is emitted from the blue LED 14 to the abutting portion 28. Here, the outline (outer contour) of the weld ball 30 in the butt portion 28 can be clearly raised by illumination from the blue LED 14 that is complementary to the color of the rectangular coil wire 26 (material is copper, for example). Thereby, the camera 10 can acquire the image of the welding ball 30 accurately and stably without being influenced by the background (such as the end face 22a of the stator core 22). Therefore, the calculation unit 16 can accurately calculate the penetration depth D of the butt 28, so that the welding quality can be accurately determined.

  Further, the camera 10 is arranged so as to make a preset inclination angle θc with respect to a direction orthogonal to the end face 22 a of the stator core 22. Further, the white LED 12 is arranged on the opposite side of the camera 10 with respect to the rectangular coil wire 26 to be imaged so as to form an inclination angle θw set in advance with respect to the axial direction of the stator core 22. Further, the blue LED 14 is arranged on the same side as the camera 10 with a rectangular coil wire 26 to be imaged as a boundary so as to form a preset inclination angle θb with respect to the axial direction of the stator core 22. Thereby, the illumination from the white LED 12 is reflected on the welding ball 30 and is incident on the camera 10, and the blue LED 14 causes the outline of the welding ball 30 and the outline of the peeling portion 32 of the rectangular coil wire 26 to appear in blue. it can. As a result, the image of the weld ball 30 can be acquired accurately and stably.

  Further, the inclination angle θc of the camera 10 is set within a range of 10 ° to 50 °. Further, the inclination angle θw of the white LED 12 is set within a range of −10 ° to −70 °. Furthermore, the inclination angle θb of the blue LED 14 is set within a range of 40 ° to 120 °, and is larger than the inclination angle θc of the camera 10. Thereby, the illumination from the white LED 12 is applied to the tip of the weld ball 30. Further, illumination from the blue LED 14 is applied to the outer peripheral portion of the weld ball 30 and the peeling portion 32 of the flat coil wire 26. Further, the illumination from the blue LED 14 is applied to the welding ball 30 so that the flat coil wire 26 arranged in the adjacent slot does not get in the way (no shadow reflection or the like occurs). In this way, the illumination of the white LED 12 and the blue LED 14 is reliably irradiated to the entire weld ball 30 to be inspected. Since the specularly reflected light from the white LED 12 can be incident on the camera 10 via the weld ball 30, the camera 10 can reliably extract the contour of the tip of the weld ball 30.

  Further, the calculation unit 16 extracts the contour E2 of the weld ball 30 and the chamfered portions (the chamfered portion 32a and the chamfered portion 32b) of the peeling portion 32 of the flat coil wire 26 from the captured image acquired by the camera 10. The penetration depth D is calculated. Thus, the contour E2 of the weld ball 30 and the chamfered portion of the peeling portion 32 can be accurately extracted from the image of the weld ball 30 that is accurately acquired as described above, and the extracted contour E2 of the weld ball 30 and The penetration depth D can be accurately calculated from the data of the chamfered portion of the peeling portion 32.

Example 3
Next, the third embodiment will be described. Components that are the same as those in the first and second embodiments are denoted by the same reference numerals, description thereof will be omitted, and different points will be mainly described.

<Configuration of welding quality inspection device>
As shown in FIG. 20, the welding quality inspection apparatus 3 of the present embodiment includes a camera 10, a red LED 13, a blue LED 14A, a blue LED 14B, a calculation unit 16, and the like.

  The camera 10 is arranged in a direction (an axial direction of the stator core 22) whose imaging direction (imaging axis 10 a) is orthogonal to the end surface 22 a of the stator core 22 constituting the stator 20. The camera 10 is disposed far away from the butting portion 28 of the imaging object. The distance L1 between the front end of the imaging unit of the camera 10 and the center of the weld ball 30 at the butting portion 28 is preferably within a range of 200 mm to 300 mm. In FIG. 20, the distance L1 is 265 mm as an example.

  The red LED 13 is arranged coaxially with the camera 10. The red LED 13 is adjusted such that the irradiation direction (optical axis 13a) is inclined with respect to the imaging direction (imaging axis 10a) of the camera 10. The red LED 13 irradiates the entire imaging range of the camera 10 including the butting portion 28 with red illumination having substantially the same color as the flat coil wire 26 (material is, for example, copper). Specifically, the red LED 13 includes a light guide plate 13b. The light guide plate 13 b is adjusted so that the irradiation direction of the red LED 13 is inclined with respect to the imaging direction of the camera 10. Thus, the red LED 13 includes the light guide plate 13b that irradiates the entire imaging range of the camera 10 obliquely.

  In addition, as for the distance L2 between the irradiation side end surface of red LED13 and the center of the welding ball 30, it is desirable to exist in the range of 50 mm-150 mm. In FIG. 20, as an example, the distance L2 is 100 mm. The red LED 13 is an example of the “first light source” in the present invention.

  The blue LED 14A and the blue LED 14B, which are a pair of blue LEDs, have a predetermined irradiation direction (optical axis 14Aa and optical axis 14Ba) set in advance with respect to the vertical direction of the imaging direction of the camera 10 (axis X in FIG. 20). Are arranged symmetrically with respect to the imaging direction of the camera 10 so as to form an inclination angle θb1 and an inclination angle θb2.

  Here, it is desirable that the inclination angle θb1 and the inclination angle θb2 are set within a range of −20 ° to 20 °. In FIG. 20, as an example, both the inclination angle θb1 and the inclination angle θb2 are set to −8 °. In addition, a total of two pairs of blue LEDs 14A and blue LEDs 14B are arranged. In this way, the blue LED irradiates the welding ball 30 with the blue illumination from four directions substantially directly lateral to the imaging direction of the camera 10.

  As described above, the blue LED 14A and the blue LED 14B irradiate the butt portion 28 with the blue illumination having a complementary color relationship with the color of the rectangular coil wire 26 from a direction different from the irradiation direction of the red LED 13. Thereby, since the blue LED 14A and the blue LED 14B can illuminate the welding ball 30 in the butt 28 with the blue light, as shown in FIG. 5, the outline (outside) of the welding ball 30 in the captured image of the camera 10. E1 can be raised.

  Here, when the gloss of the weld ball 30 is high, only the regular reflection component of the illumination light among the illumination light of the blue LED 14A or the blue LED 14B that highlights the outline of the weld ball 30 may be incident on the camera 10. . If only the regular reflection component of the illumination light of the blue LED 14A or the blue LED 14B is incident on the camera 10 in this way, the outline E1 of the weld ball 30 in the captured image of the camera 10 stands out only partially, and the weld ball 30 There is a possibility that the contour E1 may not be detected stably.

  However, in the present embodiment, the red LED 13 irradiates the entire imaging range of the camera 10 with red illumination having substantially the same color as that of the flat coil wire 26 from obliquely above the welding ball 30. Thus, the red illumination light emitted from the red LED 13 at the back of the weld ball 30 when the weld ball 30 is viewed from the camera 10 side is the coil of the coil composed of the end face 22 a of the stator core 22 and the flat coil wire 26. Reflects or diffuses at the end.

  Therefore, when the gloss of the weld ball 30 is high, even if only the regular reflection component of the illumination light of the blue LED 14A or the blue LED 14B is incident on the camera 10 as described above, it is reflected at the back of the weld ball 30. The secondary reflected light and diffused light of the red illumination that diffuses or diffuses are reflected on the outline of the weld ball 30. Thereby, the outline E1 of the weld ball 30 is detected stably. When the gloss of the weld ball 30 is low, secondary reflected light or diffused light of red illumination reflected or diffused at the back of the weld ball 30 is not reflected in the outline of the weld ball 30, but the blue LED 14A The blue LED 14B can make the outline of the weld ball 30 appear. In this way, since the image of the weld ball 30 can be obtained accurately and stably without being affected by the gloss of the surface of the weld ball 30, various dimensions of the welded part can be accurately calculated.

<Welding quality inspection method>
The welding quality inspection method using the welding quality inspection apparatus 3 having the above-described configuration is the same as the welding quality inspection method using the welding quality inspection apparatus 1 described above. Therefore, description of the welding quality inspection method using the welding quality inspection apparatus 3 is omitted.

<Effect of this embodiment>
According to the present embodiment, in the welding quality inspection apparatus 3 that inspects the welding quality in the butt portion 28 in which the flat coil wires 26 arranged in the slots of the stator core 22 are welded, the camera 10 that images the butt portion 28 and the red color A red LED 13 for illuminating the abutting section 28, a blue LED 14A and a blue LED 14B for illuminating the abutting section 28 with illumination of a color complementary to the color of the flat coil wire 26 from a direction different from the irradiation direction of the red LED 13, And a calculation unit 16 that calculates the welding length L based on the imaging data acquired by the camera 10 and determines the welding quality.

  Thereby, when imaging the abutting part 28, the red LED 13 irradiates the abutting part 28 with red illumination, and the blue LED 14A and the blue LED 14B irradiates the abutting part 28 with blue illumination. Here, by the illumination from the blue LED 14A and the blue LED 14B that are complementary to the color of the flat coil wire 26 (material is copper, for example), the outline E1 of the weld ball 30 in the butt 28 can be clearly raised. . Thereby, the camera 10 can acquire the image of the welding ball 30 accurately and stably, without being influenced by the background (end surface 22a of the stator core 22, etc.) or the reflected light from the surface of the welding ball 30. Therefore, as a result of the calculation unit 16 being able to accurately calculate the joining length L of the butt 28, the welding quality can be accurately determined.

  Further, the camera 10 is arranged in a direction orthogonal to the end face 22a of the stator core 22. The red LED 13 is adjusted so that the irradiation direction is inclined with respect to the imaging direction of the camera 10, and irradiates the entire imaging range of the camera 10 including the butt 28 with red illumination. Furthermore, the blue LED 14A and the blue LED 14B are symmetric with respect to the imaging direction of the camera 10 so that the irradiation direction forms a preset tilt angle θb1 and tilt angle θb2 with respect to the vertical direction of the camera 10 imaging direction. Is arranged. Thereby, the outline of the weld ball 30 emerges from blue to blue-green in the color correlation by the blue LED 14A and the blue LED 14B. Even if the weld ball 30 is highly glossy, the contour of the weld ball 30 is extracted by the secondary reflected light or diffused light of the red LED 13 that reflects or diffuses at the back of the weld ball 30. . As a result, the image of the weld ball 30 can be acquired accurately and stably.

  Further, the inclination angle θb1 and the inclination angle θb2 are set within a range of −20 ° to 20 °. Thereby, the outline of the welding ball 30 emerges more effectively from blue to blue-green in the color correlation by the blue LED 14A and the blue LED 14B.

In addition, the calculation unit 16 calculates the joining length L by extracting the contour E1 of the welding ball 30 in the butt unit 28 from the captured image acquired by the camera 10. As described above, the contour E1 of the weld ball 30 can be accurately extracted from the image of the weld ball 30 that is accurately acquired as described above, and the joining length L is determined from the extracted data of the contour E1 of the weld ball 30. It can be calculated accurately.

  In addition, the welding quality inspection apparatus 3 of Example 3 is using the light source which irradiates illumination of colors other than red which is substantially the same color as the flat coil wire 26, and the same color as the flat coil wire 26 instead of red LED13. An illuminating light source may be used.

  It should be noted that the above-described embodiment is merely an example and does not limit the present invention in any way, and various improvements and modifications can be made without departing from the scope of the invention. For example, the welding quality inspection apparatus 1 according to the first embodiment, the welding quality inspection apparatus 2 according to the second embodiment, and the welding quality inspection apparatus 3 according to the third embodiment may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 Welding quality inspection apparatus 2 Welding quality inspection apparatus 3 Welding quality inspection apparatus 10 Camera 12 White LED
13 Red LED
13b Light guide plate 14 Blue LED
14A Blue LED
14B Blue LED
16 Calculation part 22 Stator core 22a End face 26 Flat coil wire 28 Butting part 30 Welding ball 32 Separation part 32a Chamfering part 32b Chamfering part L Joining length D Penetration depth θc (Camera) inclination angle θbA (Blue LED) inclination angle θbB Tilt angle θb (for blue LED) Tilt angle θb1 (for blue LED) Tilt angle θb2 (for blue LED) Tilt angle θw (for blue LED) Tilt angle E1 (for white LED) Edge E2 Edge αe Edge detection line αe1 Edge detection Line αe2 Edge detection line αs Joint detection line αt Middle point detection line αp Straight line αv Perpendicular line P1 Intersection point P2 Intersection point P12 Intersection point P21 Intersection point P31 Intersection point Pc Middle point L1 Distance from weld ball to camera L2 Distance to LED

Claims (12)

In a welding quality inspection device that inspects the welding quality at a welding location where the segment coils arranged in the slots of the stator core are welded together,
An imaging unit for imaging the weld location;
A first light source for irradiating the welding spot with white illumination or illumination of the same color or substantially the same color as the segment coil;
A second light source for irradiating the welding spot with illumination of a color complementary to the color of the segment coil from a direction different from the irradiation direction of the first light source;
A calculation unit that calculates various dimensions of the welding location and determines welding quality based on imaging data acquired by the imaging unit;
Welding quality inspection device characterized by The welding quality inspection apparatus according to claim 1,
The imaging unit is disposed in a direction orthogonal to the end surface of the stator core,
The first light source is a light source that irradiates the welding spot with white illumination, and is arranged so that the irradiation direction is the same as the imaging direction of the imaging unit,
The second light source is disposed symmetrically with respect to the imaging direction of the imaging unit so that the irradiation direction forms a tilt angle set in advance with respect to the imaging direction of the imaging unit;
Welding quality inspection device characterized by The welding quality inspection device according to claim 2,
The inclination angle of the second light source is set within a range of 40 ° to 120 ° and −40 ° to −120 °;
Welding quality inspection device characterized by In the welding quality inspection device according to claim 2 or 3,
The arithmetic unit calculates a joining length by extracting a contour of a weld ball at the welding location from the imaging data acquired by the imaging unit;
Welding quality inspection device characterized by The welding quality inspection apparatus according to claim 1,
The imaging unit is arranged so as to form a preset inclination angle with respect to a direction orthogonal to the end face of the stator core,
The first light source is a light source that irradiates the welding spot with white illumination, and is inclined in advance with respect to the axial direction of the stator core on the opposite side to the imaging unit with the segment coil to be imaged as a boundary Arranged to form a corner,
The second light source is disposed on the same side as the imaging unit with the segment coil to be imaged as a boundary so as to form a preset inclination angle with respect to the axial direction of the stator core;
Welding quality inspection device characterized by The welding quality inspection device according to claim 5,
The inclination angle of the imaging unit is set within a range of 10 ° to 50 °,
An inclination angle of the first light source is set within a range of −10 ° to −70 °;
An inclination angle of the second light source is set within a range of 40 ° to 120 °;
An inclination angle of the second light source is larger than an inclination angle of the imaging unit;
Welding quality inspection device characterized by The welding quality inspection device according to claim 5 or 6,
The calculation unit calculates a penetration depth by extracting the outline of the weld ball and the both ends of the segment coil from the imaging data acquired by the imaging unit;
Welding quality inspection device characterized by The welding quality inspection apparatus according to claim 1,
The imaging unit is disposed in a direction orthogonal to the end surface of the stator core,
The first light source is a light source whose irradiation direction is inclined with respect to the imaging direction of the imaging unit and irradiates the entire imaging range of the imaging unit with illumination of the same color or substantially the same color as the segment coil,
The second light source is disposed symmetrically with respect to the imaging direction of the imaging unit such that the irradiation direction forms a tilt angle set in advance with respect to the vertical direction of the imaging direction of the imaging unit,
Welding quality inspection device characterized by The welding quality inspection apparatus according to claim 8,
The inclination angle of the second light source is set within a range of −20 ° to 20 °,
Welding quality inspection device characterized by The welding quality inspection device according to claim 8 or 9,
The arithmetic unit calculates a joining length by extracting a contour of a weld ball at the welding location from the imaging data acquired by the imaging unit;
Welding quality inspection device characterized by The welding quality inspection device according to any one of claims 8 to 10,
The illumination of the same color or substantially the same color as the segment coil is a red illumination,
Welding quality inspection device characterized by The welding quality inspection device according to any one of claims 1 to 11,
The illumination of a color complementary to the color of the segment coil is illumination of any color from blue to blue-green,
Welding quality inspection device characterized by

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