Excess adhesive detection device and excess adhesive detection method

Abstract

To provide an excess adhesive detection device and detection method for accurately detecting excess adhesive adhering to an end face of a motor core.SOLUTION: An excess adhesive detection device 10 includes: an irradiation device 13 capable of selectively irradiating infrared and ultraviolet rays toward an end face 911 of a motor core 91; a camera 12 capable of capturing the end face 911 and generating infrared image data of the end face 911, and capable of capturing the end face 911 and generating ultraviolet image data of the end face 911; and a control device 14 for analyzing the infrared image data and the ultraviolet image data. The control device 14 identifies an inspection target region 201 according to the infrared image data and detects excess adhesive on the inspection target region 201 according to the ultraviolet image data.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a surplus adhesive detection device and a surplus adhesive detection method.

Background Art

[0002] When an adhesive is used in the product assembly process, surplus adhesive may adhere to the components constituting the product. If surplus adhesive adheres to a part of a component, there is a risk that the component and other components will be unnecessarily adhered via the surplus adhesive in a subsequent process. Unnecessary adhesion may cause unexpected stress to occur between the adhered components, and in some cases, may have an adverse effect on the adhered components. Therefore, the surplus adhesive needs to be removed.

[0003] Conventionally, in order to remove surplus adhesive, visual inspection of products by workers has been performed. However, in visual inspection of products, since the inspection accuracy depends on the skills of the workers, the inspection accuracy is not stable.

[0004] Patent Document 1 discloses a method of inspecting the application state of an adhesive by irradiating an object to be inspected coated with an adhesive containing a fluorescent agent with ultraviolet light. According to the method described in Patent Document 1, since the adhesive emits light by irradiating the adhesive containing the fluorescent agent with ultraviolet light, the luminance value of the applied portion of the adhesive becomes high, and thus it is possible to determine whether the application state such as the application position and the application amount of the adhesive is acceptable.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] (Problems to be Solved by the Invention) By the way, in a motor core formed by laminating electromagnetic steel sheets, there are some in which through-holes for embedding magnets are open at the end faces. In the process of embedding a magnet in the through-hole, in order to fix the magnet in the through-hole, a magnet coated with an adhesive is inserted into the through-hole. At this time, excess adhesive may adhere to the end face of the motor core. When the adhesive adheres to the end face of the motor core, there is a risk that other components may be adhesively attached to the adhered portion unnecessarily. In this case, unnecessary stress acts between the other components adhesively attached unnecessarily and the electromagnetic steel sheet forming the motor core, and there is concern about the occurrence of defects in the electromagnetic steel sheet and the magnet. Therefore, the adhesive adhering to the end face of the motor core must be removed.

[0007] When the method described in Patent Document 1 is applied to inspect the presence or absence of the adhesive adhering to the end face of the motor core, it may be difficult to determine whether the detected adhesive is excess adhesive adhering to the end face of the motor core or necessary adhesive used to fix the magnet in the through-hole opened at the end face of the motor core.

[0008] An object of the present disclosure is to provide a surplus adhesive detection device and a surplus adhesive detection method capable of accurately discriminating surplus adhesive adhering to the end face of a motor core.

[0009] (Means for Solving the Problem) The surplus adhesive detection device of the present disclosure is a surplus adhesive detection device for detecting surplus adhesive adhering to the end face of a motor core of a core assembly including: a motor core formed in a substantially cylindrical shape having end faces at both ends in the axial direction, having a through-hole penetrating in the axial direction and opening at the end face; and a permanent magnet inserted into the through-hole and fixed in the through-hole by an adhesive, an infrared irradiation device that irradiates infrared rays onto the end face of the motor core; an ultraviolet irradiation device that irradiates ultraviolet rays onto the end face of the motor core; An imaging device that captures the end face irradiated with infrared rays to generate an infrared image of the end face and captures the end face irradiated with ultraviolet rays to generate an ultraviolet image of the end face, and an image analysis device that analyzes the infrared image and the ultraviolet image. The image analysis device identifies an inspection target area, which is an area of the end face of the motor core excluding the opening of the through hole, based on the infrared image. It is configured to detect excess adhesive present in the inspection target area based on the ultraviolet image.

[0010] In addition, the method for detecting excess adhesive of the present disclosure is a method for detecting excess adhesive adhering to the end face of a motor core of a core assembly including a motor core formed in a substantially cylindrical shape having end faces at both ends in the axial direction and having a through hole penetrating in the axial direction and opening to the end face, and a permanent magnet inserted into the through hole and fixed in the through hole with an adhesive, including an infrared image acquisition step of irradiating the end face of the motor core with infrared rays and capturing the end face to obtain an infrared image of the end face, an inspection target area identification step of identifying an inspection target area, which is an area of the end face of the motor core excluding the opening of the through hole, based on the infrared image, an ultraviolet image acquisition step of irradiating the end face of the motor core with ultraviolet rays and capturing the end face to obtain an ultraviolet image of the end face, and a detection step of detecting excess adhesive present in the inspection target area of the motor core based on the ultraviolet image.

[0011] Since the infrared absorption rate of the adhesive is higher than that of the end face of the motor core (the surface of the electromagnetic steel sheet), in the infrared image taken by irradiating infrared rays toward the end face of the motor core, the luminance value of the surface of the adhesive in the through hole opened in the end face of the motor core is lower than that of the end face of the motor core (the surface of the electromagnetic steel sheet). Therefore, in the infrared image, the adhesive in the through hole and the end face of the motor core (the surface of the electromagnetic steel sheet) can be distinguished by the luminance value, so that the accuracy of detecting the contour of the opening of the through hole provided in the motor core can be improved. Therefore, from this infrared image, by generating a mask image for removing the region (outer region) that is not the "region where the excess adhesive should be removed" in the end face of the motor core, a highly accurate mask image in which only the inspection target region is extracted can be generated. In addition, when the adhesive is irradiated with ultraviolet rays, it is excited and emits fluorescence. For this reason, the luminance of the "region where the excess adhesive adheres" in the inspection target region of the ultraviolet image taken by irradiating ultraviolet rays toward the end face of the motor core is higher than that of the "region where the excess adhesive does not adhere". Therefore, the excess adhesive existing on the end face of the motor core can be detected.

[0012] As described above, according to the excess adhesive detection device and the excess adhesive detection method of the present disclosure, the accuracy of distinguishing between the "region where the excess adhesive should be removed (that is, the surface of the electromagnetic steel sheet forming the laminated core)" and the outer region which is the other region (that is, the region inside the opening of the through hole) can be improved. Furthermore, since the adhesive is excited by the irradiation with ultraviolet rays and emits fluorescence, the luminance of the region where the excess adhesive adheres in the inspection target region of the ultraviolet image is higher than that of the region where the excess adhesive does not adhere. Therefore, the accuracy of detecting the excess adhesive adhering to the "region where the excess adhesive should be removed" can be improved. And by the image analysis device executing the detection step of detecting the excess adhesive, the accuracy of detecting the excess adhesive can be stabilized as compared with the case where an operator visually checks.

Brief Description of the Drawings

[0013]

Figure 1

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Embodiments for Carrying Out the Invention

[0014] Hereinafter, a surplus adhesive detection device and a surplus adhesive detection method according to embodiments of the present disclosure will be described.

[0015] <Configuration of the core assembly> FIG. 1 is an external perspective view of a core assembly 90. In an embodiment of the present disclosure, the core assembly 90 is shown as an inspection object of the detection device. The core assembly 90 is a component that constitutes a rotor of a motor, and is a component (including a component being manufactured) in which a permanent magnet 92 is assembled to a motor core 91 (iron core portion). As shown in FIG. 1, the core assembly 90 includes a motor core 91 and a permanent magnet 92. The motor core 91 is formed in a cylindrical shape having end faces 911 at both ends in the axial direction.

[0016] The motor core 91 is configured by laminating a plurality of electromagnetic steel sheets having the same shape in the plate thickness direction (axial direction of the motor core 91). Since a plurality of recesses are formed at predetermined positions in each electromagnetic steel sheet, a plurality of through holes that open on the end face 911 and penetrate along the axial direction are formed in the motor core 91 formed by laminating the plurality of electromagnetic steel sheets. The plurality of through holes include a plurality of through holes 912 for magnets and one through hole 913 for a shaft. The through hole 913 for the shaft is provided substantially at the center of the motor core 91 when viewed in the axial direction of the motor core 91. The plurality of through holes 912 for magnets are provided so as to form a predetermined arrangement pattern along the circumferential direction of the motor core 91 when viewed in the axial direction of the motor core 91.

[0017] A shaft is inserted into the through hole 913 for the shaft during the manufacture of the core assembly 90. Further, a permanent magnet 92 is inserted into the through hole 912 for the magnet during the manufacture of the core assembly 90. The permanent magnet 92 is adhered (fixed) to the motor core 91 with an adhesive in the through hole 912 for the magnet. For example, an epoxy resin-based thermosetting adhesive is used as the adhesive. Note that the type of the adhesive is not particularly limited, but an adhesive containing a substance that is excited by ultraviolet rays and emits fluorescence is applicable.

[0018] <Device configuration of the surplus adhesive detection device> FIG. 2 is a schematic front view of the surplus adhesive detection device 10 according to the present embodiment. As shown in FIG. 2, the detection device 10 includes a base 11, a camera 12, an irradiation device 13, a control device 14, a monitor 15, and a support column 16. The base 11 is a table on which the core assembly 90 is placed. A support column 16 is erected upward on the upper surface of the base 11. A first bracket 17 and a second bracket 18 are fixedly provided on the support column 16. The first bracket 17 and the second bracket 18 extend horizontally from the support column 16, respectively. The extending direction of the first bracket 17 and the extending direction of the second bracket 18 are substantially the same direction. Also, the second bracket 18 is located above the first bracket 17.

[0019] The irradiation device 13 is attached to the tip of the first bracket 17. In the present embodiment, the irradiation device 13 has an annular shape. The irradiation device 13 is an example of the infrared irradiation device and the ultraviolet irradiation device of the present invention. The irradiation device 13 is configured to be able to selectively irradiate infrared rays and ultraviolet rays.

[0020] FIG. 3 is a view showing the irradiation device 13, where FIG. 3(a) is a front view and FIG. 3(b) is a bottom view. As shown in FIGS. 3(a) and 3(b), the irradiation device 13 includes an annular case 131, a diffusion plate 132, a plurality of infrared sources 133, and a plurality of ultraviolet sources 134.

[0021] The annular case 131 is formed in an annular shape. A plurality of infrared sources 133 and a plurality of ultraviolet sources 134 are attached to the annular case 131. For example, an infrared LED is applied to the infrared source 133, and an ultraviolet LED is applied to the ultraviolet source 134. As shown in FIG. 3(b), the plurality of infrared sources 133 and the plurality of ultraviolet sources 134 are alternately arranged side by side along the circumferential direction of the annular case 131. Each infrared source 133 and ultraviolet source 134 is fixed to the lower surface of the annular case 131 so as to irradiate infrared rays or ultraviolet rays downward when lit.

[0022] As shown in Fig. 3(a), the diffusion plate 132 is attached to the annular case 131 so as to be positioned directly below a plurality of infrared sources 133 and a plurality of ultraviolet sources 134 attached to the lower surface of the annular case 131. The diffusion plate 132 is formed in an annular shape. The diffusion plate 132 has a function of irradiating the lower region of the diffusion plate 132 with infrared rays almost uniformly when the infrared source 133 is lit, and irradiating the lower region of the diffusion plate 132 with ultraviolet rays almost uniformly when the ultraviolet source 134 is lit. Note that the diffusion plate 132 is omitted in Fig. 3(b).

[0023] The camera 12 is an example of the imaging device of the present invention. The camera 12 is attached to the tip of the second bracket 18. The camera 12 is fixed downward to the second bracket 18 so that the imaging range is the lower region. As shown in Fig. 2, the optical axis L of the imaging lens provided in the camera 12 passes through the inner peripheral space of the annular case 131 of the irradiation device 13. Therefore, the camera 12 can image the lower region of the irradiation device 13. The light receiving element provided in the camera 12 is configured to be able to receive infrared rays, visible light, and ultraviolet rays (to have sensitivity wavelengths for infrared rays, visible light, and ultraviolet rays). Then, the camera 12 is configured to generate image data of the captured image and transmit the generated image data to the control device 14.

[0024] On the upper surface of the base 11 and at a position below the irradiation device 13, the core assembly 90 is configured to be placed so that its end face faces the camera 12. That is, the core assembly 90 is placed on the upper surface of the base 11 with one end face facing upward. Therefore, the camera 12 can image one end face (the end face 911 of the motor core 91) of the core assembly 90.

[0025] The irradiation device 13 and the camera 12 are electrically connected to the control device 14. The control device 14 is an example of the image analysis device of the present invention. The control device 14 controls the irradiation state of the irradiation device 13 and the camera 12. Also, the camera 12 transmits the data of the captured image (the data of the infrared image and the data of the ultraviolet image 21 (see FIG. 11)) to the control device 14. The control device 14 analyzes the captured images (infrared image and ultraviolet image) based on the image data transmitted from the camera 12. Note that the control device 14 is a device including a computer having a CPU, a ROM, a RAM, and a storage device (memory device). And the computer program for controlling the irradiation device 13 and the camera 12 and performing image analysis is stored in advance in the ROM of the computer. The CPU of the computer reads out this computer program from the ROM, expands it in the RAM, and executes it. Thereby, the operations described later are realized.

[0026] The control device 14 is electrically connected to the monitor 15. The control device 14 outputs the image analysis result to the monitor 15. The monitor 15 displays the input image analysis result from the control device 14.

[0027] <Manufacture of the core assembly> FIG. 4 is a diagram showing the manufacturing procedure of the core assembly 90. To manufacture the core assembly 90, first, a motor core 91 formed by laminating a plurality of electromagnetic steel sheets in the plate thickness direction and a predetermined number of permanent magnets 92 are prepared. Then, the operator applies an adhesive to a predetermined portion of the surface of the permanent magnet 92 (FIG. 4(a)). Next, the operator inserts the permanent magnet 92 to which the adhesive has been applied into the magnet through-hole 912 formed in the motor core 91 (FIG. 4(b)). Therefore, the excess adhesive (hereinafter referred to as "excess adhesive") among the adhesive applied to the permanent magnet 92 is scraped out from the magnet through-hole 912 and overflows onto the end face 911 of the motor core 91 when the permanent magnet 92 is inserted into the magnet through-hole 912. Thereafter, the operator wipes off the excess adhesive that has overflowed onto the end face 911 of the motor core 91 using a cloth or the like (FIG. 4(c)). Thereby, the core assembly 90 as an object to be inspected is manufactured.

[0028] During the manufacturing process of the core assembly 90, the excess adhesive that has overflowed onto the end face of the core assembly 90 is wiped off as described above. However, since the excess adhesive adheres to the end face 911 (surface) of the motor core 91 (electromagnetic steel sheet) that constitutes the end face of the core assembly 90, it is difficult to completely remove it. Also, if the amount of adhesive remaining on the end face 911 of the motor core 91 is large, there is a possibility that the end face 911 of the motor core 91 will be adhered to other components via the excess adhesive in a later process. In this case, stress may act on the electromagnetic steel sheet via the adhesive due to the force acting on the other component. If such stress is excessive, there is a risk that the electromagnetic steel sheet will be damaged. Therefore, it is necessary to inspect whether there is excess adhesive adhering to the end face 911 of the motor core 91, and if so, to what extent the amount (thickness) of the excess adhesive is (in particular, whether the thickness is below the allowable value or exceeds the allowable value).

[0029] <Method for Detecting Excess Adhesive> In this embodiment, the detection device 10 shown in FIG. 2 is used to detect the excess adhesive adhering to the end face 911 of the motor core 91 (in other words, the surface of the electromagnetic steel sheet that constitutes the motor core 91) that constitutes the end face of the core assembly 90. Hereinafter, the method for detecting the excess adhesive will be described.

[0030] FIG. 5 is a flowchart showing each step carried out by the inspection method according to an embodiment of the present disclosure. As shown in FIG. 5, the inspection method of the present disclosure includes (1) an inspection object placement step, (2) an infrared image acquisition step, (3) a mask image generation step, (4) an ultraviolet image acquisition step, (5) an adhesive residue map generation step, and (6) a determination step.

[0031] (1) Inspection Object Placement Step In the inspection object placement step, the operator places the manufactured core assembly 90 at a predetermined position on the upper surface of the base 11 of the detection device 10. At this time, the core assembly 90 is placed on the base 11 such that one end face 911 in the axial direction of the motor core 91 faces upward (that is, the end face 911 of the motor core 91 faces directly toward the imaging lens of the camera 12).

[0032] (2) Infrared Image Acquisition Step In the infrared image acquisition step, the control device 14 controls the irradiation device 13 so that the infrared light source 133 of the irradiation device 13 is turned on and the ultraviolet light source 134 is turned off. Thereby, the infrared light source 133 of the irradiation device 13 is turned on, and infrared light is irradiated downward from the infrared light source 133. The infrared light irradiated from the infrared light source 133 is diffused by the diffusion plate 132 and then irradiated toward the end face (end face 911 of the motor core 91) of the core assembly 90 disposed below it. The camera 12 photographs the end face 911 irradiated with infrared light. Specifically, the camera 12 receives the infrared light reflected by the end face (end face 911) of the core assembly 90 and generates data of an infrared image in which the end face (end face 911) of the core assembly 90 is shown. Then, the control device 14 acquires the data of the infrared image generated by the camera 12. This data includes data representing the luminance value of each pixel of the infrared image.

[0033] (3) Mask image generation step The mask image generation step includes an inspection target area specifying step of specifying an inspection target area 201 (see FIGS. 10 and 12), which is an area excluding the openings of the through holes 912 and 913. In the mask image generation step, the control device 14 specifies the inspection target area 201, which is an "area for detecting excess adhesive" shown in the infrared image, from the data of the infrared image acquired from the camera 12. Then, the control device 14 generates a mask image 20 using the specified inspection target area 201. In the embodiment of the present disclosure, the surface of the electromagnetic steel sheet excluding the plurality of through holes 912 and 913 in the end face 911 of the motor core 91 of the core assembly 90 is set as the inspection target area 201. Note that an area other than the inspection target area 201 (an area including the inside of the through holes 912 and 913) is referred to as an "external area 202" (see FIGS. 10 and 12).

[0034] FIG. 6 is a view showing an end face of the core assembly 90. As shown in FIG. 6, a plurality of magnet through-holes 912 and one shaft through-hole 913 are open on the end face 911 of the motor core 91 of the core assembly 90. And, the end faces of the permanent magnets 92 are exposed at the openings of the plurality of magnet through-holes 912. Since there is an adhesive necessary for fixing the permanent magnet 92 in the magnet through-hole 912, if the area inside the magnet through-hole 912 is included in the inspection target surface, the necessary adhesive may be determined to be excess adhesive adhering to the end face 911 of the motor core 91. Also, since the end face of the permanent magnet 92 is recessed from the end face of the motor core 91, even if excess adhesive adheres to the end face of the permanent magnet 92, it is unlikely that the adhered excess adhesive will come into contact with other components or the like. For this reason, the end face of the permanent magnet 92 is excluded from the inspection target area 201. For the above reasons, the areas inside these magnet through-holes 912 are external areas 202. Therefore, a mask image 20 (see FIG. 10) is required to remove these external areas 202 from the ultraviolet image 21 (see FIG. 11) described later, which is an image of the end face (end face 911) of the core assembly 90 after photographing.

[0035] In an embodiment of the present disclosure, an infrared image is used to generate the mask image 20. The reason therefor will be described below. FIG. 7A is a diagram showing a visible light image of a part of the end face of the core assembly 90 taken by the camera 12 with visible light irradiated on the end face (end face 911) of the core assembly 90. Further, FIG. 7B is a diagram showing the distribution range of the luminance values of the inspection target region 201 and the distribution range of the luminance values of the external region 202 in the visible light image shown in FIG. 7A. Visible light is not reflected at the opening of the end face 911 of the motor core 91, and the reflectance of visible light on the surface of the permanent magnet 92 is lower than the reflectance of visible light on the surface of the electromagnetic steel sheet. For this reason, as can be seen from FIG. 7B, the luminance value of the external region 202 is lower than the luminance value of the inspection target region 201. However, when visible light is irradiated on the end face of the core assembly 90, the visible light is reflected by the adhesive present in the magnet through-hole 912 (the adhesive attached to the end face of the permanent magnet 92), so that the luminance value of the adhesive portion in the magnet through-hole 912 becomes high (see part X in FIG. 7A). On the other hand, when an adhesive adheres to the inspection target region 201 (the surface of the electromagnetic steel sheet), the luminance value of the region where the adhesive adheres is lower than the luminance value of the surface of the electromagnetic steel sheet.

[0036] Therefore, as shown in FIG. 7B, the upper limit value of the luminance value of the region corresponding to the magnet through-hole 912, which is the external region 202, becomes high due to the adhesive in the magnet through-hole 912, and the lower limit value of the luminance value of the inspection target region 201 becomes low due to the excess adhesive attached. As a result, the upper limit value of the distribution range of the luminance values of the external region 202 becomes higher than the lower limit value of the distribution range of the luminance values of the inspection target region 201. That is, the distribution range of the luminance values of the external region 202 and the distribution range of the luminance values of the inspection target region 201 partially overlap. For this reason, in the method of specifying the inspection target region 201 using the luminance value of each pixel of the visible light image, the inspection target region 201 and the external region 202 cannot be accurately distinguished. In other words, the detection accuracy of the inspection target region 201 decreases.

[0037] FIG. 8A is a diagram showing a partial ultraviolet image of the end face (end face 911) of the core assembly 90 taken by the camera 12 with ultraviolet rays irradiated on the end face. Further, FIG. 8B is a diagram showing the distribution range of the luminance values of the inspection target region 201 and the distribution range of the luminance values of the external region 202 among the images shown in FIG. 8A. When ultraviolet rays are irradiated on the end face of the core assembly 90, the adhesive in the magnet through-hole 912 is excited by the irradiated ultraviolet rays to emit fluorescence, so that the luminance value of the external region 202 becomes high. On the other hand, even when the surplus adhesive attached to the surface of the electromagnetic steel sheet is irradiated with ultraviolet rays, the surplus adhesive emits light, but since the thickness of the surplus adhesive is extremely small, the amount of light emission is small. Also, since the electromagnetic steel sheet itself absorbs ultraviolet rays, the luminance value of the entire inspection target region 201 becomes low. Therefore, as shown in FIG. 8B, the distribution range of the luminance values of the external region 202 includes the distribution range of the luminance values of the inspection target region 201. Therefore, in the method of specifying the inspection target region 201 using the luminance value of each pixel of the ultraviolet image 21, the inspection target region 201 and the external region 202 cannot be distinguished.

[0038] FIG. 9A is a diagram showing a partial infrared image of the end face (end face 911) of the core assembly 90 taken by the camera 12 with infrared rays irradiated on the end face. Further, FIG. 9B is a diagram showing the distribution range of the luminance values of the inspection target region 201 and the distribution range of the luminance values of the external region 202 among the images shown in FIG. 9A. As shown in FIG. 9B, the upper limit value of the distribution range of the luminance values of the external region 202 is lower than the lower limit value of the distribution range of the luminance values of the inspection target region 201. That is, the distribution range of the luminance values of the external region 202 is lower than the distribution range of the luminance values of the inspection target region 201, and the distribution range of the luminance values of the inspection target region 201 and the distribution range of the luminance values of the external region 202 do not overlap. This is because when infrared rays are irradiated on the end face of the core assembly 90, the amount of infrared rays absorbed by the adhesive in the magnet through-hole 912 is large, so that the reflection at the adhesive portion in the magnet through-hole 912 is suppressed. As a result, the luminance value of the region in the magnet through-hole 912 is kept low as a whole. Therefore, the upper limit value of the luminance value of the external region 202 becomes lower than the lower limit value of the luminance value of the inspection target region 201.

[0039] Then, a first threshold value is set between the upper limit value of the distribution range of the luminance values in the external region 202 and the lower limit value of the distribution range of the luminance values in the inspection target region 201. Note that the first threshold value is set in advance before executing the detection method and stored in the storage device of the control device 14. Then, based on the data of the infrared image, the control device 14 identifies the region formed by the pixels with luminance values equal to or higher than the first threshold value among the pixels constituting the infrared image as the inspection target region 201, and identifies the region formed by the pixels with luminance values less than the first threshold value as the external region 202 (inspection target region identification step). Thereby, the inspection target region 201 and the external region 202 can be distinguished. In this way, by using the data of the infrared image, the inspection target region 201 and the external region 202 can be identified with high precision based on the luminance values of the respective pixels obtained from the data of the infrared image. Thereby, when generating the adhesive residue map 22 in the adhesive residue map generation step described later, the control device 14 can extract only the luminance values of the inspection target region 201 and delete the luminance values of the external region 202.

[0040] Also, as described above, since the distribution range of the luminance values in the inspection target region 201 and the distribution range of the luminance values in the external region 202 do not overlap, misjudging the inspection target region 201 as the external region 202 and misjudging the external region 202 as the inspection target region 201 are prevented or suppressed. Therefore, the accuracy of identifying the inspection target region 201 can be improved. Then, the control device 14 generates a mask image 20 for masking the external region 202 using the identified inspection target region 201. FIG. 10 is a diagram schematically showing the mask image 20. The white area in the figure is the inspection target region 201, and the black filled area is the external region 202.

[0041] (4) Ultraviolet image acquisition step In the ultraviolet image acquisition process, the control device 14 controls the irradiation device 13 so that the ultraviolet light source 134 of the irradiation device 13 lights up and the infrared light source 133 turns off. As a result, the ultraviolet light source 134 of the irradiation device 13 lights up, and ultraviolet light is irradiated downward from the ultraviolet light source 134. The ultraviolet light irradiated from the ultraviolet light source 134 is diffused by the diffusion plate 132 and then irradiated toward the end face (end face 911 of the motor core 91) of the core assembly 90 disposed below it. The camera 12 captures the end face 911 irradiated with ultraviolet light. Specifically, the camera 12 receives the ultraviolet light reflected from the end face (end face 911) of the core assembly 90 and generates data of the ultraviolet image 21 in which the end face (end face 911) of the core assembly 90 is shown. Then, the control device 14 acquires the data of the ultraviolet image 21 generated by the camera 12. In this ultraviolet image acquisition process, the relative positional relationship between the camera 12 and the core assembly 90, which is the inspection object, is maintained in the same positional relationship as in the infrared image acquisition process. That is, after the infrared image acquisition process, the ultraviolet image acquisition process is executed without moving the core assembly 90. FIG. 11 is a diagram schematically showing the ultraviolet image 21. Since the adhesive emits fluorescence, the luminance value of the region where the adhesive is attached tends to be higher than the luminance value of the region where the adhesive is not attached. In FIG. 11, the white area is the region where the luminance value has increased due to the attachment of the adhesive, and the hatched area is the region where the luminance value is low because the adhesive is not attached. When the adhesive is attached to the end face of the permanent magnet 92, the luminance value of the region corresponding to the end face of the permanent magnet 92 also increases.

[0042] (5) Adhesive Residual Map Generation Process The adhesive residue map 22 (see FIG. 12) is a map showing the positions and thicknesses of the residual adhesives adhering to the inspection target area 201. In the adhesive residue map generation step, the adhesive residue map 22 is generated using the ultraviolet image 21 acquired in the ultraviolet image acquisition step and the mask image 20 generated in the mask image generation step. Specifically, the control device 14 superimposes the mask image 20 on the ultraviolet image 21 and deletes the luminance values (luminance information) of the areas in the data of the ultraviolet image 21 that overlap with the external area 202 included in the mask image 20. As a result, only the inspection target area 201 is extracted from the ultraviolet image 21, and the adhesive residue map 22 from which the external area 202 is excluded is generated. Since the relative positional relationship between the camera 12 and the core assembly 90 is the same in the infrared image acquisition step and the ultraviolet image acquisition step, the control device 14 simply superimposes the mask image 20 on the ultraviolet image 21 (that is, without adjusting the relative positional relationship between the pixels included in the data of the ultraviolet image 21 and the pixels included in the data of the mask image 20), and can delete the luminance values of the external area 202 from the data of the ultraviolet image 21.

[0043] FIG. 12 is a diagram schematically showing the adhesive residue map 22. The data of the adhesive residue map 22 includes only the luminance values of the inspection target area 201. Therefore, it can also be said that the data of the adhesive residue map 22 is the data of the ultraviolet image 21 from which the luminance values of the external area 202 have been deleted.

[0044] Then, the control device 14 estimates the thickness of the adhesive remaining in the inspection target area 201 from the luminance values of the pixels in the adhesive residue map 22 (the inspection target area of the ultraviolet image). Here, when an epoxy resin-based thermosetting adhesive is irradiated with ultraviolet rays, it is excited and emits fluorescence. Specifically, since the adhesive components, reinforcing materials, curing agents, etc. contain components that cause ultraviolet fluorescence excitation, these components emit light when irradiated with ultraviolet rays. Examples of the components that cause ultraviolet fluorescence excitation include 4,4'-isopropylidenediphenol epichlorohydrin polymer (bisphenol A type epoxy resin), benzophenone, benzotriazole, naphthalenesulfonic acid, thiocarboxylic acid, glass fiber, mineral filler, amine-based curing agent, acid anhydride-based curing agent, etc.

[0045] Therefore, in the data of the ultraviolet image 21, the luminance value of the pixel corresponding to the area where the surplus adhesive adheres is higher than the luminance value of the pixel corresponding to the area where no adhesive adheres. In FIG. 12, the white area indicates the area where the surplus adhesive adheres and the luminance value is high, and the hatched area indicates the area where no surplus adhesive adheres and the luminance is low. As shown in FIG. 12, since the luminance value information of the external area 202 (the area corresponding to the through holes 912 and 913) is deleted by the mask image 20, the presence or absence of the adhesion of the surplus adhesive is not determined for the external area 202.

[0046] Also, as the thickness of the adhesive increases, the amount of light emission by fluorescence increases. Therefore, as the thickness of the adhesive increases, the luminance value increases. That is, this luminance value has a positive correlation with the thickness of the surplus adhesive. Therefore, the thickness of the surplus adhesive can be estimated from the luminance value. The relationship between the luminance value of the pixel and the thickness of the surplus adhesive is measured in advance and stored in the storage device of the control device 14. A 3D scanner can be used to measure the thickness of the surplus adhesive. In the embodiment of the present disclosure, the data of the adhesive residue map 22 has the luminance values of the pixels corresponding to each position, but the data of the adhesive residue map 22 may have the values of the thickness of the surplus adhesive at each position (that is, the values of the thickness of the residual adhesive estimated from the luminance values).

[0047] (6) Determination Step The determination step includes a detection step of detecting excess adhesive present in the inspection target area 201. In the determination step, the control device 14 detects an area composed of pixels with a luminance value equal to or greater than a second threshold value from the generated adhesive residue map 22 (detection step). Note that the second threshold value is a luminance value corresponding to the lower limit value of the thickness of the adhesive exceeding the allowable value, and is a value defined in advance. Then, when there is an area where the luminance value is equal to or greater than the second threshold value, the control device 14 identifies that the area is an area where "excess adhesive with a thickness exceeding the allowable value is attached" among the inspection target area 201 of the ultraviolet image. And when there is no area where "adhesive with a thickness exceeding the allowable value is attached", the control device 14 determines that the core assembly 90 is a good product. On the other hand, when there is an area where "adhesive with a thickness equal to or greater than the allowable value remains", the control device 14 determines that the core assembly 90 is a non-conforming product. Then, the control device 14 transmits the adhesive residue map 22 and the determination result to the monitor 15. The monitor 15 displays the adhesive residue map 22 and the determination result. As an aspect of the adhesive residue map 22 displayed on the monitor 15, for example, a figure obtained by superimposing a contour map showing the thickness of the adhesive on a figure schematically showing the end face of the motor core 91 can be applied.

[0048] And, by displaying the adhesive residue map 22 and the determination result on the monitor 15, the operator can confirm the determination result, and when the core assembly 90 is a non-conforming product, can grasp at which position on the end face 911 of the motor core 91 excess adhesive with a thickness exceeding the allowable value (second threshold value) is attached. Then, after wiping off the excess adhesive, the operator executes (1) again and causes the detection device 10 to execute the steps of (2) to (6). And the steps of (1) to (6) are repeated until it is determined in the determination step that the core assembly 90 is not a non-conforming product.

[0049] In an embodiment of the present disclosure, the determination of whether or not excess adhesive having a thickness exceeding the allowable value is attached is made by the control device 14 based on the adhesive residue map 22 instead of by visual inspection of an operator. Therefore, the accuracy of the determination can be improved. In other words, since the determination can be made regardless of the skill of the operator, it is possible to prevent or suppress variations in the determination (stabilize the accuracy).

[0050] In the method for detecting excess adhesive according to the embodiment of the present disclosure, (1) the operator executes the inspection object placement step, and (2) the computer of the control device 14 executes the infrared image acquisition step to (6) the determination step. In this case, after the operator executes (1) the inspection object placement step, the operator performs a predetermined operation for causing the control device 14 to execute (2) the infrared image acquisition step to (6) the determination step. Then, when the computer of the control device 14 detects this predetermined operation, it executes (2) the infrared image acquisition step to (6) the determination step in series.

[0051] <Summary of the Embodiment> (1) The excess adhesive detection device according to the embodiment of the present disclosure is an excess adhesive detection device that detects excess adhesive attached to the end face 911 of the motor core 91 of a core assembly 90 including a motor core 91 formed in a substantially cylindrical shape having end faces 911 at both ends in the axial direction and having a through hole that penetrates in the axial direction and opens to the end face 911, and a permanent magnet 92 inserted into the through hole and fixed in the through hole by an adhesive, an infrared irradiation device (irradiation device 13) that irradiates infrared rays to the end face 911 of the motor core 91, an ultraviolet irradiation device (irradiation device 13) that irradiates ultraviolet rays to the end face 911 of the motor core 91, a photographing device (camera 12) that photographs the end face 911 irradiated with infrared rays to generate an infrared image of the end face 911 and photographs the end face 911 irradiated with ultraviolet rays to generate an ultraviolet image of the end face 911, and an image analysis device (control device 14) that analyzes the infrared image and the ultraviolet image, and is provided with the image analysis device is Based on the infrared image, identify an inspection target area 201, which is the area of the end face 911 of the motor core 91 excluding the opening of the through hole. Based on the ultraviolet image, detect excess adhesive present in the inspection target area 201.

[0052] A method for detecting excess adhesive according to an embodiment of the present disclosure is a method for detecting excess adhesive adhering to the end face 911 of a motor core 91 of a core assembly 90, the motor core 91 being formed in a substantially cylindrical shape having end faces 911 at both ends in the axial direction and having a through hole penetrating in the axial direction and opening to the end face 911, and a permanent magnet 92 inserted into the through hole and fixed in the through hole by an adhesive, the method comprising: an infrared image acquisition step of irradiating the end face 911 of the motor core 91 with infrared rays and photographing the end face 911 to obtain an infrared image of the end face 911; an inspection target area identification step of identifying an inspection target area, which is the area of the end face 911 of the motor core 91 of the core assembly 90 excluding the opening of the through hole, based on the infrared image; an ultraviolet image acquisition step of irradiating the end face 911 of the motor core 91 with ultraviolet rays and photographing the end face 911 to obtain an ultraviolet image of the end face 911; and a detection step of detecting excess adhesive present in the inspection target area of the motor core 91 based on the ultraviolet image.

[0053] Since the infrared absorption rate of the adhesive is higher than that of the end face 911 (the surface of the electromagnetic steel sheet) of the motor core 91, in the infrared image taken by irradiating infrared rays toward the end face 911 of the motor core 91, the brightness of the surface of the adhesive in the through hole opening to the end face 911 of the motor core 91 is lower than that of the end face 911 of the motor core 91. Therefore, since the adhesive in the through hole and the end face 911 of the motor core 91 can be distinguished by the brightness value in the infrared image, the accuracy of detecting the contour of the opening of the through hole provided in the motor core 91 can be improved. Accordingly, by generating the mask image 20 for removing the external region 202 which is not the region where the surplus adhesive should be removed from the end face 911 of the motor core 91 from this infrared image, a highly accurate mask image 20 in which only the inspection target region 201 is extracted can be generated. Also, when the adhesive is irradiated with ultraviolet rays, it is excited and emits fluorescence. For this reason, the brightness of the region where the surplus adhesive is attached in the inspection target region of the ultraviolet image taken by irradiating ultraviolet rays to the end face 911 of the motor core 91 becomes higher compared to the brightness of other regions. Therefore, the surplus adhesive attached to the end face 911 of the motor core 91 can be detected.

[0054] As described above, according to the surplus adhesive detection device and the surplus adhesive detection method of the present disclosure, the accuracy of distinguishing between "the region where the surplus adhesive should be removed (that is, the surface of the electromagnetic steel sheet forming the laminated core)" and "the region where the presence of the surplus adhesive is allowed (that is, the region inside the opening of the through hole)" can be improved. Further, since the adhesive is excited by the irradiation with ultraviolet rays and emits fluorescence, the brightness value of the region where the surplus adhesive is attached in the inspection target region of the ultraviolet image becomes higher than the brightness value of the region where the surplus adhesive is not attached. Therefore, the accuracy of detecting the surplus adhesive attached to the "region where the surplus adhesive should be removed" can be improved.

[0055] (2) The configuration that the image analysis device (control device 14) specifies the region formed by the pixels having a brightness value equal to or higher than the first threshold value among the pixels constituting the infrared image as the inspection target region 201 can be applied.

[0056] In addition, the inspection target area specifying step is a step of specifying, as an inspection target area 201, an area formed by pixels having a luminance value equal to or greater than a first threshold value among the pixels constituting the infrared image.

[0057] In the infrared image taken by irradiating infrared rays toward the end face 911 of the motor core 91, the distribution range of the luminance values of the external area 202 is lower than the distribution range of the luminance values of the inspection target area 201, and the upper limit value of the distribution range of the luminance values of the external area 202 is lower than the lower limit value of the distribution range of the luminance values of the inspection target area 201. That is, the distribution range of the luminance values of the external area 202 and the distribution range of the luminance values of the inspection target area 201 do not overlap. Therefore, by setting the first threshold value between the upper limit value of the distribution range of the luminance values of the external area 202 and the lower limit value of the distribution range of the luminance values of the inspection target area 201, the accuracy of detecting the inspection target area 201 can be improved.

[0058] (3) A configuration can be applied in which the image analysis device determines that an excess adhesive having a thickness exceeding an allowable value exists in an area formed by pixels having a luminance value equal to or greater than a second threshold value among the inspection target areas of the ultraviolet image.

[0059] In addition, the detection step is a step of determining that an excess adhesive exists in an area formed by pixels having a luminance value equal to or greater than a second threshold value among the inspection target areas of the ultraviolet image.

[0060] When the adhesive is irradiated with ultraviolet light, it is excited and emits fluorescence. Therefore, in the inspection target area of the ultraviolet image taken by irradiating the end face 911 of the motor core 91 with ultraviolet light, the brightness of the "area where surplus adhesive is attached" is higher than that of other areas. Also, the brightness value of the area where the thickness of the attached surplus adhesive is thick is higher than the brightness value of the area where the thickness of the attached surplus adhesive is thin. That is, the brightness value of each pixel in the inspection target area of the ultraviolet image has a tendency that the brightness value of the area where the surplus adhesive is attached is higher than the brightness value of the area where no surplus adhesive is attached, and the brightness value of the area where the thickness of the attached surplus adhesive is thick is higher than the brightness value of the area where the thickness of the attached surplus adhesive is thin. Therefore, by setting the brightness value corresponding to the lower limit value of the thickness exceeding the allowable limit of the attached surplus adhesive as the second threshold value, and determining that there is surplus adhesive in the area formed by the pixels whose brightness value is equal to or higher than the second threshold value, it is possible to accurately detect that surplus adhesive with a thickness exceeding the allowable limit is attached.

[0061] As described above, the embodiments of the present disclosure have been described, but the present invention is not limited to the above embodiments. For example, in the embodiment, an example using the annular irradiation device 13 has been described, but the irradiation device 13 can also be configured in a hemispherical shape as shown in FIG. 13, for example. In this case, by irradiating each infrared source 133 and ultraviolet source 134 to the inner peripheral side, uniform infrared or ultraviolet light can be irradiated toward the end face 911 of the motor core 91 without using a diffusion plate. Also, when using the hemispherical irradiation device 13 shown in FIG. 13, the camera 12 can be installed at a position avoiding the irradiation device 13 so that it can photograph the end face 911 of the motor core 91.

[0062] In addition, in the above-described embodiment, the second threshold value used in the determination step (detection step) is set to the luminance value corresponding to the lower limit value of the thickness at which the thickness of the excess adhesive adhering to the end face 911 of the motor core 91 exceeds the allowable value. On the other hand, the second threshold value may be set to a luminance value that is equal to or higher than the luminance value of the region where no adhesive is attached and equal to or lower than the luminance value of the region where the adhesive is attached. According to this, even when a small amount of excess adhesive adheres to the inspection target region of the end face 911 of the motor core 91, the adhesion of the excess adhesive can be detected. Thus, the technology according to the present disclosure can be modified as long as it does not deviate from the gist thereof.

Explanation of Signs

[0063] 10... Detection device for excess adhesive, 12... Camera (imaging device), 13... Irradiation device (infrared irradiation device, ultraviolet irradiation device), 14... Control device (image analysis device), 90... Core assembly, 91... Motor core, 133... Infrared source, 134... Ultraviolet source, 911... End face of motor core, 912... Through hole for magnet of motor core, 913... Through hole for shaft of motor core, 92... Permanent magnet

Claims

1. A motor core formed in a substantially cylindrical shape having end faces at both ends in the axial direction, the motor core having a through hole that penetrates in the axial direction and opens to the end face, and a permanent magnet inserted into the through hole and fixed in the through hole with an adhesive. A surplus adhesive detection device for detecting surplus adhesive adhering to the end face of the motor core of the core assembly, comprising: An infrared irradiation device that irradiates infrared rays onto the end face of the motor core; An ultraviolet irradiation device that irradiates ultraviolet rays onto the end face of the motor core; An imaging device that captures the end face irradiated with infrared rays to generate an infrared image of the end face, and captures the end face irradiated with ultraviolet rays to generate an ultraviolet image of the end face; An image analysis device that analyzes the infrared image and the ultraviolet image, The image analysis device: Based on the infrared image, identifies an inspection target area that is an area of the end face of the motor core excluding the opening of the through hole; Based on the ultraviolet image, detects surplus adhesive present in the inspection target area. Surplus adhesive detection device.

2. The surplus adhesive detection device according to Claim 1, wherein the image analysis device identifies, as the inspection target area, an area formed by pixels having a luminance value equal to or higher than a first threshold value among the pixels constituting the infrared image. Surplus adhesive detection device.

3. The surplus adhesive detection device according to Claim 2, wherein the image analysis device determines that there is surplus adhesive having a thickness exceeding an allowable value in an area formed by pixels having a luminance value equal to or higher than a second threshold value in the inspection target area of the ultraviolet image. Surplus adhesive detection device.

4. A method for detecting surplus adhesive adhering to the end face of a motor core of a core assembly including a motor core formed in a substantially cylindrical shape having end faces at both ends in the axial direction, the motor core having a through hole that penetrates in the axial direction and opens to the end face, and a permanent magnet inserted into the through hole and fixed in the through hole with an adhesive, the method comprising: An infrared image acquisition step of irradiating infrared rays onto the end face of the motor core and capturing the end face to acquire an infrared image of the end face; An inspection target area identification step of identifying, based on the infrared image, an inspection target area that is an area of the end face of the motor core excluding the opening of the through hole; An ultraviolet image acquisition step of irradiating the end face of the motor core with ultraviolet rays and photographing the end face to obtain an ultraviolet image of the end face; A detection step of detecting excess adhesive present in the inspection target region of the motor core based on the ultraviolet image; A method for detecting excess adhesive, comprising:

5. The method for detecting excess adhesive according to claim 4, wherein the inspection target region specifying step specifies, as the inspection target region, a region formed by pixels having a luminance value equal to or higher than a first threshold value among the pixels constituting the infrared image.

6. The method for detecting excess adhesive according to claim 5, wherein the detection step determines that there is excess adhesive having a thickness exceeding an allowable value in a region formed by pixels having a luminance value equal to or higher than a second threshold value in the inspection target region of the ultraviolet image.

Images