JP2015102393A - Coil gap measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of accurately measuring a gap between coils despite the existence of light reflection due to the coils.SOLUTION: Light irradiation means applies striped pattern light to a stator while moving the light, and imaging means obtains a plurality of luminance distributions by imaging the stator multiple times. An integrated value of difference of the luminance for each pixel in the luminance distribution is calculated. When the integrated value exceeds a threshold, a part of the stator, which corresponds to the pixels for which the integrated value is calculated, is determined as a gap between coils, so that the gap is measured.

Description

  The present invention relates to a method for measuring a gap between coils.

  2. Description of the Related Art Conventionally, a rotating electric machine in which a stator having a stator core formed by arranging a plurality of divided cores in an annular shape is known. In such a stator, a coil is wound around adjacent teeth. It is necessary to provide a gap between the coils wound around the adjacent teeth so as to ensure insulation between the coils.

  Currently, the gap between the coils is often confirmed by visual inspection by an operator. However, in recent years, there has been a great demand for miniaturization of rotating electrical machines, and the gaps between coils have become smaller, making visual confirmation difficult.

  Patent Document 1 describes a technique for measuring an air gap (gap) between a rotor (rotor) and a stator (stator). In this technology, a fan-shaped laser beam is emitted from a light source device provided on one outside so that light passes through the air gap and reaches the other, and the laser beam is detected by a light receiving device provided on the other side. To do. The position is quantized in the lateral direction of the detected laser beam, and the quantized light intensity is sampled and compared with the alarm level.

JP-A-8-191556

  When the gap between the coils is to be automatically measured, it can be conceived to irradiate the stator with light and detect the light passing through the gap between the coils with the light receiving device.

  However, the coil is made of metal or the like, has a curved surface, and reflects light. Therefore, since the light reflected by the coil is also incident on the light receiving device, there is a risk of erroneous detection.

  In view of the above, an object of the present invention is to provide a method capable of accurately measuring a gap between coils even when light is reflected by the coils.

  The coil gap measuring method of the present invention is a method for measuring a gap between coils wound around teeth arranged adjacent to a stator, wherein the light irradiating means has a strong light emission band having a relatively large light intensity. And the stator irradiated with the striped pattern light having a relatively weak light emission band with a relatively small light intensity alternately in a striped pattern, positioned on the opposite side of the light irradiating means across the stator, and two-dimensionally A step of obtaining a first luminance distribution by imaging by an imaging unit composed of arranged pixels, and the light irradiation unit shifting the stripe pattern in a direction different from a stripe direction of the stripe pattern light. A step in which the imaging means images the stator irradiated with light to obtain a second luminance distribution; and a step of calculating a luminance difference for each pixel in the first luminance distribution and the second luminance distribution; , The difference is preset Compared with the values, if the difference exceeds the threshold value, the portion of the stator corresponding to the pixels determined the difference as a void, and measuring the gap between the coils.

  According to the coil gap measuring method of the present invention, the imaging means images the stator irradiated with different striped pattern light to obtain two luminance distributions, and the difference in luminance for each pixel in these luminance distributions is used as a threshold value. When the difference exceeds the threshold value, the stator portion corresponding to the pixel for which the difference is obtained is assumed to be a gap.

  When the irradiated light passes through the coil gap, the light from the emission band is directly received by the imaging means, so that the light is emitted from the strong emission band or from the weak emission band. Depending on whether there is a large difference in luminance received by the corresponding pixel, the difference becomes large and exceeds the threshold value. On the other hand, when the irradiated light is reflected by the coil, the reflected light is not directly received from the light emission band, so the difference in luminance received by the pixels is not affected unless there is a large change in the amount of light as the entire light irradiation means. This is because the difference is less and the difference is less than or equal to the threshold value.

  Therefore, the influence by the reflected light can be eliminated, and the gap between the coils can be accurately measured.

  It is also preferable to obtain other luminance distributions such as the third luminance distribution by shifting the stripe pattern light irradiated when the first and second luminance distributions are obtained in a direction different from the stripe direction. . In this case, the difference may be an integrated value of the difference.

  In the coil gap measuring method of the present invention, the stripe direction of the stripe pattern light is parallel to the longitudinal direction of the gap between the coils, and the direction in which the light irradiation means shifts the stripe pattern light is orthogonal to the stripe direction. It is preferable that the direction is.

  In this case, the influence by reflected light can be more effectively eliminated.

FIG. 4 is a partial front view of a stator that is measured by the coil gap measuring method according to the embodiment of the present invention. 1 is a schematic side view of a coil gap measuring device that is preferably used in a coil gap measuring method according to an embodiment of the present invention. The figure explaining the state which irradiated the striped pattern light between the coils. The flowchart explaining the coil clearance measuring method which concerns on embodiment of this invention.

  A coil gap measuring method according to an embodiment of the present invention will be described.

  Referring to FIG. 1, the present method is adjacent to the salient pole concentrated winding stator 2 of the rotating electrical machine around which the coil 1 is wound so that the coils 1 wound around adjacent teeth of the stator core have different phases. This is a method of measuring the interval between coils 1 of different phases. The stator 2 is used, for example, in a three-phase AC type driving motor of a hybrid vehicle.

  As shown in FIG. 1, the stator 2 is obtained by attaching a plurality of split cores 3 in an annular shape to a stator holder (not shown). The divided cores 3 are arranged in the order of the three phases of the U phase, the V phase, and the W phase.

  Each divided core 3 is an assembly of a stator core (not shown) made of a laminated steel plate in which a plurality of substantially T-shaped steel plates are integrated, and an insulating bobbin (insulator) externally fitted to the teeth of the stator core. A winding frame 4, a coil (winding) 1 wound around the winding frame 3, and a metal electrode (terminal).

  Next, the coil gap measuring device 10 that is preferably used when performing the coil gap measuring method according to the embodiment of the present invention will be described.

  As shown in FIG. 2, the coil gap measuring device 10 includes a light irradiation unit 11, an imaging unit 12, and a control unit 13.

  Here, the light irradiation means 11 is disposed below the holder 14 that holds the stator 2 horizontally, and irradiates light toward the stator 2 disposed above.

  The light irradiation means 11 irradiates the stator 2 with a striped pattern light having a strong light emission band having a relatively large light intensity and a weak light emission band having a relatively small light intensity alternately in a stripe shape. Referring to FIG. 3, the stripe direction of the stripe pattern light is parallel to or substantially parallel to the longitudinal direction of the gap between the coils 1.

  The light irradiation means 11 is connected to the control means 13 and displays a striped light pattern in which a strong light emission band with a relatively large amount of light and a weak light emission band with a relatively small amount of light are alternately consecutive. It is possible to do.

  Further, the light irradiating means 11 can irradiate the stator 2 by shifting the stripe pattern light in a direction different from the stripe direction of the stripe pattern light, here, in a direction orthogonal to the stripe direction. It has become.

  The mode in which the light irradiation means 11 shifts the striped pattern light is not limited. For example, the striped pattern light may be shifted in a time periodic manner or in a time discrete manner.

  The width of the strong light emission band and the width of the weak light emission band may be the same or different. Further, the widths of the strong emission bands and the weak emission bands may be the same or different. The sum of the width of each strong light emission band and the width of the weak light emission band is preferably equal to or less than the minimum design value of the coil interval.

  Here, the light irradiation means 11 is composed of a surface light source in which point light sources are arranged in a matrix. However, the structure of the light irradiation means 11 is not limited to this. For example, the light irradiation unit 11 includes a surface light source that projects uniform light, a slit plate that is disposed between the surface light source and the stator 2, and has striped slits. It may be movable.

  Further, the light irradiation means 11 may be constituted by a plurality of linear light sources that project uniform light arranged in parallel, and this may be movable by the control means 13.

  Moreover, it is preferable that the light emission intensity | strength of each strong light emission zone | band and each weak light emission zone | band is the same, and striped pattern light is a striped pattern of binary luminance distribution. Furthermore, it is preferable that the difference in emission intensity between the strong emission band and the weak emission band is large. The emission intensity of the weak emission band may be 0, that is, the weak emission band may be a dark band.

  The imaging means 12 is installed on the opposite side of the striped pattern light projection means 11 with the stator 2 interposed therebetween. Here, the imaging means 12 is arranged so as to image the lower stator 2 above the holder 14 that holds the stator 2 horizontally. Note that the imaging unit 12 preferably includes a telecentric optical system capable of shooting with a large depth of field.

  The imaging unit 12 includes a plurality of pixels (imaging elements) in which light emitted from the light irradiation unit 11 is two-dimensionally arranged such as light that has passed through the coil gap and light reflected by the surface of the coil 1. Light is received by a CCD camera or the like, and the brightness of light received by each image sensor is output to the control means 13.

  In addition to the light irradiation control unit 21 that controls the light irradiation unit 11 and the imaging control unit 22 that controls the imaging of the imaging unit 12, the control unit 13 includes a luminance distribution acquisition unit 23, a difference integrated value acquisition unit 24, and a determination unit 25. And a measurement unit 26.

  The luminance distribution acquisition unit 23 acquires the luminance for each pixel from the image data captured by the imaging unit 12. Specifically, the signal detected by the imaging device of the imaging unit 12 is amplified by an amplifier, and then output as luminance data converted into a digital value by an A / D converter.

  The difference integrated value acquisition unit 24 integrates the luminance difference for each pixel based on the luminance data for each pixel acquired by the luminance distribution acquisition unit 23, and acquires the difference integrated value for each pixel.

  The determination unit 25 compares the difference integrated value for each pixel acquired by the difference integrated value acquisition unit 24 with a preset threshold value, and if the difference integrated value exceeds the threshold value, the difference integrated value is obtained. It is determined that the portion of the stator 2 corresponding to the pixel is a gap.

  The measurement unit 26 obtains a gap between the coils based on the arrangement of the pixels that the determination unit 25 has determined that the portion of the stator 2 is a gap. Note that the distance from the imaging means 12 to the stator 2 is constant, and the width on the stator 2 corresponding to one pixel is also constant, and this width can be easily obtained by a known technique.

  Hereinafter, a coil gap measuring method according to an embodiment of the present invention using the coil gap measuring apparatus 10 will be described with reference to FIG.

  First, the light irradiation control unit 21 controls the light irradiation means 11 to irradiate the stator 2 with the striped pattern light (STEP 1).

  In this state, the imaging control unit 22 controls the imaging unit 12 to capture the stator 2 and obtain image data (STEP 2).

  Next, the light irradiation control unit 21 controls the light irradiation unit 11 to irradiate the stator 2 with the striped pattern light shifted in the direction orthogonal to the stripe direction from STEP 1 (STEP 3).

  In this state, the imaging control unit 22 controls the imaging unit 12 to capture the stator 2 and obtain image data (STEP 4).

  Then, STEP3 and STEP4 are repeated a preset number of times. This number is preferably determined based on the amount of shift of the striped pattern light. That is, when the widths of the strong light emission band and the weak light emission band are the same, when the shift amount is 1 / N cycle, the number of imaging is N times or more. For example, when the deviation amount is a half cycle, the number of times of imaging may be two or more, and when the amount of deviation is a quarter period, the number of times of imaging may be four or more. In this way, the number of times may be determined so that there are cases where all the imaging portions of the stator 2 have light emitted from the strong light emission band and the weak light emission band, respectively.

  After the predetermined number of times of imaging (STEP 5: YES), the luminance distribution acquisition unit 23 acquires luminance data for each pixel from the image data obtained by imaging in STEPs 2 and 4 (STEP 6).

  Then, the difference integrated value acquisition unit 24 integrates the luminance difference for each pixel based on the luminance data for each pixel acquired in STEP 6, and acquires the difference integrated value for each pixel (STEP 7). This difference may be, for example, a difference from the luminance obtained by the previous imaging or a difference from the luminance obtained by the first imaging.

  Then, the determination unit 25 compares the difference integrated value for each pixel acquired in STEP 7 with a preset threshold value, and if the difference integrated value exceeds the threshold value, it corresponds to the pixel for which the difference integrated value is obtained. It is determined that the portion of the stator 2 to be operated is a gap (STEP 8).

  When the light emitted from the light irradiation means 11 passes through the coil gap, the light from the light emission band is directly received by the imaging means 12, so that the light is emitted from the strong light emission band or the weak light emission band. There is a large difference in luminance received by the corresponding pixel of the image pickup means 12 depending on whether the light is emitted from. Therefore, in this case, the difference integrated value is large and exceeds the threshold value.

  On the other hand, when the light irradiated from the light irradiation means 11 is reflected by the coil 1, the reflected light is also incident on the pixel whose corresponding region is a region shielded by the coil 1. However, since the reflected light is not directly received from the emission band, the change in luminance is small unless there is a large change in the amount of light of the entire light irradiation unit 11. Therefore, in this case, the difference integrated value is small and less than the threshold value. In other words, the threshold value is determined by experiments, simulations, or the like so that the influence of such reflected light can be eliminated.

  Next, the measurement unit 26 obtains the gap between the coils based on the pixel arrangement determined in STEP 8 that the portion of the stator 2 is a gap (STEP 9). In addition, the gap between the coils may not be calculated numerically, but may be inspected to determine whether it is normal beyond a predetermined set value.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this.

  DESCRIPTION OF SYMBOLS 1 ... Coil, 2 ... Stator, 3 ... Divided core, 10 ... Coil gap | interval measuring apparatus, 11 ... Light irradiation means, 12 ... Imaging means, 13 ... Control means, 14 ... Holder, 21 ... Light irradiation control part, 22 ... Imaging control unit, 23 ... luminance distribution acquisition unit, 24 ... difference integrated value acquisition unit, 25 ... determination unit, 26 ... measurement unit.

Claims (2)

A method for measuring a gap between coils wound around teeth disposed adjacent to a stator,
The light irradiation means irradiates the stator with the striped pattern light having alternately a strong light emission band having a relatively large light intensity and a weak light emission band having a relatively small light intensity in a stripe pattern, with the stator interposed therebetween. A step of obtaining an image of a first luminance distribution by an image pickup unit that is located on the opposite side of the light irradiation unit and configured by pixels arranged in a two-dimensional manner;
A step in which the imaging unit images the stator irradiated with the striped pattern light by shifting the light irradiation unit in a direction different from the stripe direction of the striped pattern light to obtain a second luminance distribution;
Calculating a luminance difference for each pixel in the first luminance distribution and the second luminance distribution;
The difference is compared with a preset threshold, and when the difference exceeds the threshold, the gap between the coils is measured assuming that the portion of the stator corresponding to the pixel for which the difference is obtained is a gap. A coil gap measuring method characterized by the above.   The stripe direction of the stripe pattern light is parallel to the longitudinal direction of the gap between the coils, and the direction in which the light irradiation unit shifts the stripe pattern light is a direction orthogonal to the stripe direction. The coil gap measuring method according to claim 1.