JP2001258231A - Tacho-generator of brushless motor, inspecting method therefor, inspecting method for position detection element of brushless motor, and inspecting method for winding coil of brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem associated with the tacho-generators of brushless motors that they are visually inspected for pattern short-circuit and this impairs productivity and reliability. SOLUTION: TP's 5, 6, 7, 8, 14, 15, 16, 17, 18, 19, 28, 29, and 30 are installed among the tacho-generator, the Hall elements, and the winding coils of the brushless motor as appropriate. A specified voltage is applied to a pair of these TP's and the voltage at TP of terminals with no voltage applied thereto is measured. The measurements are compared or subjected to arithmetic operation to see whether the samples are to be accepted or rejected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection of a brushless motor, and more particularly to an inspection of an FG pattern of a tachogenerator of a brushless motor, an inspection of a position detecting element of a permanent magnet of a rotor, and an inspection of a winding coil of a brushless motor. It is characterized by the following.

[0002]

2. Description of the Related Art A wave winding for a tachogenerator constituting a brushless motor, a position detecting element for detecting the position of a rotor (usually a hall element, and used in the same manner as a hall element), and a brushless motor are driven. And a printed circuit board for electrically connecting each component to a motor drive circuit, or a work of soldering them, may cause a problem such as short circuit or disconnection. This causes a problem that the brushless motor does not rotate or rotation unevenness occurs. In order to prevent such a problem, the resistance value of each component and the state of the brushless motor are inspected, and those having a short circuit or disconnection are selected.

[0003] Printed circuit boards are characterized by their manufacturing characteristics.
A short circuit often occurs with an adjacent conductive pattern (usually a copper pattern, which is used in the same manner as a copper pattern) due to an etching residue or the like. In order to prevent the copper pattern from being short-circuited, the distance between adjacent copper patterns is made as large as possible. However, in many cases, the distance cannot be made large due to dimensional restrictions. Therefore, in consideration of the occurrence of a short circuit, a method of inspecting the resistance value of a pattern in which a short circuit is likely to occur, such as inspecting the resistance value, and making the short circuit a lot out to protect shipping quality is generally adopted. Is being done.

On the other hand, in a tachogenerator of a brushless motor, priority is given to the output signal accuracy of the tachogenerator. For this reason, when the tachogenerator is formed of a copper pattern on a printed circuit board, a return winding for canceling noise caused by one rotation of the disc-shaped rotor of the brushless motor is set as close as possible to the wave winding. In order to cancel the radiation noise, the lead wires from the wave winding to the control circuit are arranged in parallel and as close as possible. As a result, the frequency of occurrence of short circuits increases as compared with the case where a normal circuit is formed on a printed circuit board. Further, when the brushless motor is downsized, the area of the printed circuit board is reduced, so that the space for arranging the copper patterns is restricted, so that the interval between the copper patterns is narrowed, and a short circuit is likely to occur.

When a tachogenerator of a brushless motor is formed on a printed circuit board, the resistance between the terminals of the tachogenerator is close to 0 Ω, so that it is possible to discriminate between a short circuit and a normal one in an inspection with a normal resistance value. Is difficult to do. For this reason, in a printed circuit board that constitutes a tacho generator, as a method of sorting by shipping inspection, an operator inspects the printed circuit board visually or with a magnifying glass.

FIG. 7 shows a printed circuit board constituting a tachogenerator of a conventional brushless motor. In FIG. 7, in a corrugated tacho generator 2 formed by a copper pattern formed on a printed circuit board 1, terminals 3 and 4 are arranged at the start and end of the tacho generator 2, and can be connected to a drive circuit.
Here, when the diameter of the brushless motor is 30 mm, the line length of the copper pattern of the tacho generator 2 is about 200 mm. Since the cross-sectional area of the copper pattern of a general printed circuit board is 0.035 mm × 0.15 mm, the total length of the tachogenerator (terminals 3 and 4) is determined from the specific resistance of copper.
The resistance value during the period is about 0.8Ω. If a short circuit occurs at point A on such a printed circuit board 1,
The resistance value between the terminals 3 and 4 is 0.1 to 0.2Ω. In this case, by using a high-precision ohmmeter and taking measures to suppress measurement errors such as contact resistance with the test pin,
It can be distinguished from the case where there is no short circuit.

However, for example, when a short circuit occurs at the point B, the resistance value between the terminals 3 and 4 of the tacho generator becomes 0.7 to 0.8 Ω, and the measures for reducing the measurement error described above are taken. Even so, it is virtually impossible to make a judgment in mass production. On the other hand, when a short circuit occurs at the point B, the speed control signal outputs only 5/6 as compared with a normal case. In addition, since the effect of reducing the detection error due to the sum of the signals obtained by the detection over the entire circumference is lost, the accuracy of the speed control signal is deteriorated. That is, even if a short circuit occurs in either A or B, it becomes a serious defect as a brushless motor. Next, FIG. 8 shows an equivalent circuit diagram of a general Hall element. FIG. 8 illustrates that the internal resistances R1 to R4 of the Hall element are connected in a ten o'clock manner around the intersection 9 and connected to the respective terminals 10 to 13. Here, the terminal 10 and the terminal 11 will be described as an input side, and the terminal 12 and the terminal 13 will be described as an output side. Normally, the Hall element has a mini-mold type or super mini-mold type package shape used for transistors and the like, and the pitch between adjacent terminals is as narrow as 1.9 mm or 1.3 mm. May be short-circuited to an adjacent terminal, and conduction failure may occur due to a phenomenon such as potato soldering or tunneling. In addition, a problem may occur that cracks are generated in the internal resistances R1 to R4 of the Hall element due to heat, mechanical stress, static electricity, or the like due to solder. Due to such a problem, there is a problem that the brushless motor does not rotate or rotation unevenness occurs due to the fact that the position of the rotor cannot be detected or the rotor is detected in a state where the position is shifted. In order to identify such a problem at the stage of mounting the Hall element, a method of inspecting the resistance value between the terminals 10 and 11 and between the terminals 12 and 13 is often adopted. However, Hall elements generally have the characteristic that resistance values vary greatly for reasons of manufacturing. For this reason, even if it is an obvious defect that a short circuit occurs between the adjacent terminals 11 and 12, there is a problem that the short circuit cannot be detected because it is within a normal range of resistance value variation. For example, terminal 1
54 for a resistance specification between 240 and 550Ω between 0 and 11
0 Ω, resistance value standard between terminals 12 and 13 240-550
For a Hall element that is 500Ω to Ω, R1 = R
2 = 270Ω, R3 = R4 = 250Ω, and terminal 11
When a short circuit occurs between terminals 10 and 12, terminals 10 and 1
The resistance value between 1 is 270 + 1 / (1/250 + 1/27)
0) to 400Ω. This is within the range of the resistance standard between 240 and 550 Ω between the terminals 10 and 11 of the Hall element, and is determined to be OK in the above inspection. As a result, defects cannot be detected at the stage when the Hall element is attached, defects are found at the stage when the brushless motor is completed, processing costs and dismantling costs are lost during that time, and at the worst, the finished brushless motor is discarded become.

In particular, when a crack occurs in the internal resistance portion of the Hall element described above, the resistance value changes only a few percent from the normal value at the beginning of the crack. The crack progresses in the state,
The worst disconnection may occur. Further, the occurrence of such cracks causes the resistance values of the internal resistances R1 and R2 to shift, thereby changing the potential level of the Hall element output signal, and exceeding the preset input allowable range of the motor drive circuit. In some cases, the position detection signal of the rotor based on the Hall element output signal cannot be read as a motor drive circuit. We want to detect such problems at the early stage and select them as defective, but as mentioned above, the amount of change in the resistance value at the initial stage is extremely small, so there is a possibility that normal resistance value inspection may not be able to identify it. There is. At present, soldering from the manufacturing process of Hall elements,
Furthermore, in all processes up to the inspection process of the brushless motor, strict control of the temperature of the soldering iron and thorough measures against static electricity for workers should be strictly handled, and the possibility of cracks and other defects may occur. Has been reduced. Despite these precautionary measures, the fact is that such problems continue to occur suddenly. Further, in a winding coil for driving a brushless motor, a resistance value per phase is often 5Ω or less due to a demand for motor characteristics. In particular, in a brushless motor mounted on an electric device used with a battery, since it is driven at a low voltage such as 6 V or 3 V,
In order to secure a level of the current supplied to the motor of 1 A, a low resistance value per phase is required. On the other hand, there is a measurement error of a general resistance meter of about 0.1 Ω, a change of about 0.1 Ω at a change of 10 ° C. due to temperature characteristics, and a measurement error due to contact resistance with a test pin. There is a problem that cannot be measured.

In a wound coil, the resistance value varies due to the variation in the conductor diameter of the wire.
For example, a wire having a conductor diameter of 0.15 mm has a wire diameter variation of ± 0.003 mm, so that a wound coil having the same number of turns has a resistance value variation of ± 4%. This means that even if the winding length of the winding coil, that is, the number of windings changes by 8%, it is possible to determine that the winding is OK. There is a problem that rotation unevenness occurs. Furthermore, due to poor measurement accuracy, there is a problem that even if a short circuit occurs in a part of a plurality of winding coils of each phase, it cannot be detected. As described above, in the brushless motor, since the resistance value of the object to be inspected is small, or a change in the resistance value due to a defect with respect to the resistance value standard is relatively small, there is a means for inspecting with high accuracy. There is a problem that there is no inspection or omission of inspection.

[0010]

As described above, when a wave winding or a winding coil of a tachogenerator is formed by pattern wiring on a printed circuit board, a short-circuit or a disconnection due to a resistance test usually performed is performed. The detection has a problem in reliability and is generally inspected visually. However, there is a problem in that the visual inspection may increase the inspection labor cost and may omit the inspection. A similar problem also occurs in a brushless motor using a low-resistance coil having a resistance equivalent to one of the winding coil.

Further, in a brushless motor using a Hall element, when inspecting for short-circuit or conduction failure when soldering terminals and destruction of the Hall element due to handling,
Since the variation in the resistance value of the Hall element is large and there is a problem in the reliability in the resistance value inspection, it is common to use both the resistance value inspection and the visual inspection. As in the case of the tachogenerator described above, there have been problems such as an increase in inspection labor and an omission of inspection.

[0012]

In order to solve the above-mentioned problems, a test point (hereinafter referred to as TP) is appropriately arranged on a wave winding, a position detecting element, and a winding coil of a tachogenerator of a brushless motor of the present invention. Then, a predetermined voltage is applied to one of them, the TP at the other end is set to GND, the potential of the TP which is a non-voltage application terminal is measured, and the one or a plurality of measured values are compared or predetermined. Is characterized in that the short-circuiting, disconnection or short-circuiting or disconnection in the vicinity of the wave winding, the position detecting element, and the winding coil can be inspected by performing the arithmetic processing.

According to the present invention, a defect in a wave winding, a position detecting element, and a winding coil of a tachogenerator of a brushless motor can be electrically detected. A method can be provided.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tachogenerator for a brushless motor according to a first aspect of the present invention has a stator having a multi-phase winding coil opposed to a rotor having a permanent magnet having a plurality of magnetic pole pairs. A tachogenerator for generating a signal for controlling speed by forming a wave winding by a conductive pattern on a printed circuit board fixed to the stator facing the permanent magnet of the rotor, the brushless motor having: At least three or more test points are arranged from the beginning, end, and the middle of the winding to detect a short-circuit state of the conductive pattern of the wave winding. This makes it possible to inspect a defect of the wave winding.

Next, a tachogenerator for a brushless motor according to a second aspect of the present invention is the tachogenerator for a brushless motor according to the first aspect, arranged between the start and end of the wave winding. At least one test point is extracted from a portion divided into a line length ratio of approximately 1: 3 with respect to a line length from a start end to an end of the wave winding, This makes it possible to inspect a defect of a wave winding of a tachogenerator in a brushless motor.

According to a third aspect of the present invention, there is provided a tachometer for a brushless motor according to the first aspect, wherein a test point is set for a part or all of the test points. Instead of arranging, it is characterized in that it can be pulled out and connected to the outside by a connector or the like, and it is possible to inspect a defect of a wave winding of a tachogenerator in a brushless motor.

Next, a method for inspecting a tachogenerator of a brushless motor according to a fourth aspect of the present invention is a method for inspecting a tachogenerator of a brushless motor, in which a multi-phase winding coil is connected to a rotor having a permanent magnet having a plurality of magnetic pole pairs. A brushless motor having a stator provided with a tacho generator for generating a signal for controlling a speed by forming a wave winding by a conductive pattern on a printed circuit board fixed to the stator opposed to the permanent magnet of the rotor, At least three test points are arranged from the start and end of the wave winding and the middle thereof, and a predetermined voltage is applied to one of the start and end of the wave winding and the other is set to GND. In this state, the potential of a test point arranged in the middle of the wave winding is measured to detect a short-circuit state of the conductive pattern forming the wave winding. And it is obtained by, it is an electrically testable short pattern of a printed board constituting a tacho-generator in the brushless motor.

According to a fifth aspect of the present invention, there is provided a method for inspecting a position detecting element of a brushless motor, comprising: a multi-phase winding coil opposed to a rotor having a permanent magnet having a plurality of magnetic pole pairs; A position detecting element for detecting a position of a permanent magnet of the rotor is soldered onto a printed circuit board fixed to the stator, and two pairs of terminals of the position detecting element are provided. A predetermined voltage is applied to a test point at one end of a pair of terminals of the position detection element, the other end is set to GND, and another pair of non-voltage application terminals of the position detection element By measuring the potential of the test point arranged at the position, then changing the voltage application terminal pair, measuring the potential of the test point, and comparing the measured potential values, the position detection element It is those that have characterized the inspecting damage and the like short of its periphery, it is an electrically testable defect position sensitive detector.

Next, a method for inspecting a position detecting element of a brushless motor according to a sixth aspect of the present invention is the method for inspecting a position detecting element of a brushless motor according to a fifth aspect. A part or all of the brushless motor is characterized in that it can be pulled out and connected to the outside by a connector or the like instead of arranging a test point, so that a failure of the position detecting element in the brushless motor can be electrically inspected. .

Next, a method for inspecting a position detecting element of a brushless motor according to a seventh aspect of the present invention is a method of inspecting a position detecting element of a brushless motor, wherein a multi-phase winding coil is opposed to a rotor having a permanent magnet having a plurality of magnetic pole pairs. In a brushless motor having a stator comprising: a plurality of position detecting elements for detecting the position of a permanent magnet of the rotor are connected in series and arranged, and a pair of input terminals of the position detecting elements arranged in series A predetermined voltage is applied to one end of the position detection element, the other end is set to GND, and a resistor having a predetermined resistance value is connected to all output side terminal pairs of the position detection element via a relay element as GND terminals. The potential of each pair of test points arranged at the output terminal of the position detection element is measured when the relay is turned on and when it is turned off, and the measured potential value is subjected to a predetermined arithmetic processing. , Which was characterized in that to enable checking the short state of the breakdown and around the position detection element, it is an electrically testable defect position sensitive detector in the brushless motor.

Next, a method for inspecting a winding coil of a brushless motor according to an eighth aspect of the present invention is directed to a method of inspecting a wound coil of a brushless motor, wherein the resistance value per phase is opposed to a rotor having a permanent magnet having a plurality of magnetic pole pairs. Is a three-phase brushless motor having a stator having a winding coil having a resistance of about 5Ω or less, wherein test points are respectively arranged on the winding coil side connected to the motor drive circuit, and the test points for the one-phase test point are provided. Apply a predetermined voltage, set the test point of the other phase to GND, measure the potential of the test point of the remaining phase, then alternate the voltage applied test point, measure the potential of each test point, It is characterized by inspecting for short-circuits in the winding coil and short-circuits in the vicinity of the short-circuiting. It is an air-inspect possible.

Next, according to a method for inspecting a winding coil of a brushless motor according to a ninth aspect of the present invention, a resistance value per phase is opposed to a rotor having a permanent magnet having a plurality of magnetic pole pairs. Is a three-phase brushless motor having a stator having a winding coil having a resistance of about 5Ω or less, wherein test points are respectively arranged on the winding coil on the side connected to the motor drive circuit, and one of the three phases is A predetermined voltage is applied to a test point of a phase via a resistor having a predetermined resistance value, and a test point of another phase is connected to a GND through a resistor having a predetermined resistance value. Measurement, then change the voltage application test point,
The potential of each test point is measured, and a predetermined arithmetic processing is performed on the measured potential to make it possible to inspect the resistance value of the winding coil. It is possible to electrically inspect the wire coil for defects.

Next, according to a tenth aspect of the present invention, there is provided a method for inspecting a winding coil of a brushless motor, wherein the resistance value per phase is opposed to a rotor having a permanent magnet having a plurality of magnetic pole pairs. Is a three-phase brushless motor having a stator having a winding coil of about 5Ω or less, wherein test points are respectively arranged on the winding coil side connected to a motor drive circuit, and a plurality of phases constituting each phase are further provided. At least one or more test points are arranged between the winding coils or at positions where the conductive patterns forming the winding coils are divided, and the test points connected to the one-phase motor drive circuit are arranged. A predetermined voltage is applied to the test point, and the test point on the side connected to the motor drive circuit of the other phase is set to GND, and the potential of the test point is measured. By performing a predetermined calculation process on the measured potential value, it is possible to inspect for defects related to the number of turns of the winding coil, and it is possible to electrically inspect defects of the winding coil in the brushless motor. Is what you do.

Next, a method for inspecting a wound coil of a brushless motor according to claim 11 of the present invention is the same as the method for inspecting a wound coil of a brushless motor according to claim 9 or 10. The process is characterized by performing a subtraction process and a comparison process, and makes it possible to electrically inspect the short-circuit state of the winding coil of the brushless motor.

Next, a method for inspecting a winding coil of a brushless motor according to a twelfth aspect of the present invention is the method for inspecting a winding coil of a brushless motor according to an eighth, ninth or tenth aspect of the present invention. In the above, a part or all of the test points can be pulled out and connected to the outside by a connector or the like instead of arranging the test points. Inspection is possible. (Embodiment 1) An embodiment of the present invention described in claims 1 to 4 of the present invention will be described below with reference to FIG.

FIG. 1 shows a printed circuit board constituting a tachogenerator of a brushless motor according to claims 1 to 3 of the present invention, and an inspection circuit according to claim 4 of the present invention. In FIG. 1A, in a tachogenerator 2 having a corrugated wave winding formed of a copper pattern on a printed circuit board 1, a terminal 3, which is disposed at the start and end thereof,
4 enables connection to the drive circuit. Test points (hereinafter referred to as TP) 5 and 6 are arranged near the terminals 3 and 4, respectively, and the line length of the tachogenerator 2 is drawn from a point 7 where the line length is roughly divided into 1: 3.
TP8 is located.

For example, if the size of the brushless motor is a diameter φ
The line length of the tachogenerator 30 is about 200 mm, and the cross-sectional area of the copper pattern of a general printed circuit board is 0.0 mm.
From the specific resistance of copper of 35 mm × 0.15 mm, the resistance value of the entire length of the tacho generator is about 0.8Ω. In such a tacho generator, a voltage of 1 V is applied to TP5 and TP5 is applied.
By measuring the potential of TP8 with GND set to 6, detection of a pattern short failure occurring between the tachogenerators is performed.

When there is no defect such as a pattern short, the resistance value of TP5 to TP8 of the inspection circuit shown in FIG. 1B is 3/4 of 0.8Ω, 0.6Ω and TP8 to TP6.
Has a resistance of 1/4 and becomes 0.2Ω, and the potential of TP8 becomes 2Ω.
It becomes 50 mV. On the other hand, when a pattern short occurs at the point B, the pattern is shortened by 0.05Ω each due to the pattern short, so that the potential at the test point 8 is 0.15 / (0.15 + 0.55) ×
It becomes 1000 to 214 mV. When the potential is 250 mV when there is no problem such as the above-mentioned pattern short, B
Potential 21 when there is a pattern short at point
By identifying 4 mV, it is possible to inspect a pattern short failure of the tacho generator. This is easily identifiable based on the detection accuracy of the potential measuring device of 0.1 mV. Assuming that a pattern short occurs at a place where another similar pattern short may occur,
By performing the same calculation and setting TP8 so that the potential at TP8 does not become 250 mV, inspection becomes possible.

Here, the line length of the tachometer is 5: 5.
The reason why TP8 is not set at the position where the pattern is divided is to prevent the potential of TP8 from becoming 500 mV even when the location where the pattern short occurs at point A, and to prevent the normal case from being identified. It is. In addition, TP8 when the pattern short occurs and when it does not occur
Is approximate, it becomes difficult to inspect the short circuit of the tachogenerator by the inspection circuit. In the inspection circuit, assuming a case where a short circuit occurs at all places where a pattern short circuit may occur, in such a case, the detected potential does not approximate the potential in a normal state,
It is important to set the position of TP8. Also, TP
If 8 is set to 1: 9 or 4: 6, when a pattern short circuit occurs, the amount of change in the potential of TP8 is reduced, and the discrimination ability is reduced. In consideration of these points, the arrangement of the test points 8 is preferably 1: 3. Depending on the pattern shape of the tachogenerator and the measurement accuracy of the ohmmeter to be used, it may be possible to perform inspections other than 1: 3, and sometimes impossible at 1: 3. In such a case, a point that satisfies the above-described condition may be found near 1: 3.

Further, when the number of magnetized poles of the permanent magnet of the brushless motor is increased and the number of teeth of the wave winding of the tachogenerator is significantly increased as compared with the example shown in FIG. In some cases, it becomes impossible to provide a potential difference from a normal one. In this case, the TP disposed between the start end and the end of the tachogenerator is 1
By comparing the potential at each TP with two or more, it is possible to more reliably detect a pattern short.

Further, when precise measurement is required, the measurement error of TP8 caused by the variation of the power supply voltage, the contact resistance between each TP and the measurement terminal, etc.
There is also a possibility that it is not possible to distinguish between a normal one and a short-circuited one. In such a case, the potentials of TP5 and TP6 are measured using a measuring circuit and a measuring device similar to the measuring circuit and measuring device for measuring the potential of TP8, and the potential difference between TP5 and TP8 and the potential difference between TP6 and TP8.
By comparing the potential difference between and, the measurement accuracy can be improved. (Embodiment 2) Next, claim 5 and claim 6 of the present invention
The embodiment of the invention described in (1) will be described with reference to FIG. FIG. 2 shows an equivalent circuit of a general Hall element and a part of an inspection circuit according to the present invention. The internal resistances R1 to R4 of the Hall element are connected at an intersection 9 around a cross point 9 and respective terminals are connected. 10 to 13 are connected.

In general, a Hall element has such a property that the resistance value varies greatly due to manufacturing restrictions. However, since many of the factors of the variation are due to variations in the film thickness during film formation and the purity of the film components, there is almost no relative difference in resistance between the internal resistances R1 and R2 and between R3 and R4. know. Cracks due to solder heat, static electricity, and mechanical stress do not occur frequently at the same time, but occur at any of the fragile points of the internal resistances R1 to R4. Has the property that it is unlikely to occur. Utilizing these, it is possible to detect defects in the Hall element and its surroundings by the following inspection means.

The terminals 10 and 11 are hereinafter referred to as the input side, and the terminal 1
2 and 13 are output sides, and the input side internal resistances R1 and R2 are inspected (this case is referred to as (A)), and the opposite case where the output side internal resistances R3 and R4 are inspected (this case is referred to as (B ) Will be described.

(A) TPs 14 to 17 corresponding to the respective terminals are arranged near the terminals 10 to 13 and
ND is applied and 1 V is applied to TP14. In this state, TP
16 and 17 are measured to determine the internal resistance R1 of the Hall element.
And that R2 is equal. That is, TP16,
If the potential of 17 is 500 mV, the values of the resistors R1 and R2 are equal.

(B) Similarly, TP17 is set to GND, and TP
By applying 1 V to 16 and measuring the potentials of TP14 and TP15, it is checked that the values of the internal resistances R3 and R4 of the Hall element are equal. That is, the potential of TP14, TP17 is 5
If it is 00 mV, the values of the resistors R3 and R4 are equal.

By performing the above inspection, even when a short circuit occurs due to a solder bridge or the like in the adjacent terminals 11 and 12, it is possible to identify the short circuit as follows. For example, when the resistance value between the terminals 10 and 11 is 540Ω and the resistance value between the terminals 12 and 13 is 500Ω, that is, R1 = R2 = 270Ω and R3 = R4 = 250
When a short circuit occurs between the terminals 11 and 12 in the Hall element of Ω, in the above (A), the TP
The potential of No. 16 is 0 mV, and can be easily detected. Further, since TP16 becomes GND and resistors R2 and R3 are connected in parallel, the potential of TP17 becomes 325 mV, which can be detected similarly.

Further, when a minute crack is generated in the internal resistance portion of the Hall element due to static electricity or stress due to heat and pressure, for example, a problem that the resistance value of the internal resistance R1 is increased by 2% occurs, as follows. Becomes detectable. In a Hall element in which the resistance value between the terminals 10 and 11 is 500Ω and R1 and R2 are both 250Ω, only the internal resistance R1 is reduced to 25 by cracking.
When the resistance becomes 5Ω, the potential of TP17 becomes 495 mV in the test circuit state of (A). 50 for normal
By changing 5 mV with respect to 0 mV, the internal resistance R1
, It is possible to detect even a small difference such that the resistance value changes by 2%. Since the detection accuracy of a general potential measuring instrument is 0.1 mV, and since it is derived from the ratio of resistance values, it is hardly affected by resistance change due to temperature at the time of inspection and contact resistance of TP, even a potential difference as small as 5 mV Identification can be made possible. That is, (A), (B)
By inspecting the Hall element in the inspection state described above, it is possible to easily and highly accurately inspect for defects such as a shorter and a disconnection in the Hall element and its periphery.

In the above description, when it is difficult to switch the voltage input location or the potential measurement location due to restrictions on production equipment or production tact, the inspection can be performed by the following method. That is, in FIG. 2 (b), TP1 is assumed to be a Hall element inside the dotted line X and an inspection device outside the X.
4 is applied to set TP15 to GND, and TP16, 1
By measuring the potential of No. 7, a result equivalent to the content inspected in the above two inspection states (A) and (B) is obtained. A resistor R5 having a predetermined resistance value is connected to the TPs 16 and 17 via the relay element 21 to make GND, and the potentials of the TPs 16 and 17 are measured when the relay element 21 is turned on and when the relay element 21 is turned off, respectively. First, when the relay element 21 is turned off, it is the same as the inspection state of the above (A), and it is possible to inspect that the internal resistances R1 and R2 of the Hall element are equivalent. Next, when the relay element 21 is turned on, the resistances R3 and R3 are obtained from the voltage applied to the intersection 9 of the Hall element.
5 determines the potential of TP16, and the resistors R4 and R5 determine the potential of TP17. From this, if the internal resistances R3 and R4 of the Hall element are normal, the potentials of TP16 and TP17 become the same, and if there is a potential difference, it can be determined that the Hall element is defective. In particular, in a brushless motor in which a plurality of Hall elements are generally used, the effect of reducing the loss of the measuring device and the measuring time by switching the voltage application terminal is increased. (Embodiment 3) An embodiment of the present invention described in claim 7 of the present invention will be described with reference to FIG. FIG.
Shows an equivalent circuit diagram of a state in which three Hall elements are connected in series and a measurement circuit according to the present invention.
Resistances R1a, R2a, R1b, R2b, R1c, R2c
Are the input-side resistors, and the resistors R3a, R4a, R3b, R
4b, R3c, and R4c are output-side resistors. The three pairs of Hall elements to which the internal resistances are connected in a timely manner are connected to TP18 and TP18, respectively, in a state where the input terminals 11a and 10b and 11b and 10c of the Hall elements are connected.
9, TPs 14a and 15c are connected to input terminals 10a and 11c to which the Hall elements are not connected to each other, and TPs are connected to output terminals of the respective Hall elements.
16a, 17a, 16b, 17b, 16c, and 17c are connected. In this state, the input side of each Hall element,
A predetermined voltage is applied to the output side TP, and the potential of each TP is measured by the inspection method according to the measurement procedures (A) and (B) described in the second embodiment. In this case, it is possible to detect a defect such as a short circuit or a disconnection. However, in order to reduce the loss of the measuring device and the measuring time by switching the voltage application point twice for each Hall element, the following measuring method is performed.

TP16, 17 connected to each Hall element
Then, a resistor R5 having a predetermined resistance value is connected via the relay element 21 to be connected to GND. And 1V to TP14a
Is applied, the potential of each TP is measured in two kinds of states, that is, when the relay element 21 is turned on and when the relay element 21 is turned off, with the TP 15c being GND, and the voltage application point is switched by performing arithmetic processing. , An abnormality can be detected in each internal resistance of each Hall element.

As an example of the measurement calculation, all the internal resistances of each Hall element are 250Ω, the resistance R5 is 1 kΩ,
When the relay element 21 is turned off, the potential of each TP is as follows. TP18 is 667 mV, TP19 is 33
833 mV, TP16 for 3 mV, TP16a, 17a
b, 17b are 500 mV, test points 16c, 17
c becomes 167 mV. From the potential measurement results of the respective TPs, the voltage V1a applied to the internal resistance R1a on the input side of the Hall element is obtained from the potential V14a of the TP14a and the potential V16a of the TP16a by (V1a) = (V14a)-(V16
a), the voltage V2a applied to the internal resistance R2a of the Hall element becomes (V2a) = (V1
6a)-(V18), the voltage becomes 167 mV, and V1a =
V2a, the internal resistance R1 of the Hall element
It can be seen that the resistance values of a and R2a are the same, and there is no problem. By the same calculation, the internal resistance R1 of the other Hall element is calculated.
The resistance difference between b and R2b and between R1c and R2c can be inspected. As a result, it can be determined that there is no problem such as a short circuit or disconnection on the input side of the Hall element and its surroundings.

Next, when the relay element 21 is switched from OFF to ON, the TPs 16a and 17a have 470 mV, the test points 16b and 17b have 185 mV, and the test points 16c and 17c have 49 mV. These values vary due to variations in the internal resistance value of each Hall element,
As long as the output-side internal resistances R3 and R4 of each Hall element do not have a relative difference, V16 = V17, which indicates that the Hall element has no abnormality. For example, the internal resistance R3
When a is changed from 250Ω to 255Ω, V16
Based on the difference between a = 467 mV and V17a = 470 mV, it can be determined that the Hall element has an abnormality.

In addition, as the brushless motor is downsized, a space for providing all the TPs described above may not be able to be secured. In particular, among the terminals described above, a terminal that does not interfere with the motor even when not connected to the motor drive circuit is often not provided with a TP because a terminal for connecting to the motor drive circuit is not provided. Therefore, assuming a case where the TPs 18 and 19 cannot be arranged, a method for determining the potentials of the TPs 18 and 19 in the same manner as described above without measuring the potential will be described below.

In the above-described inspection, the potential V1 of TP18
8 and the potential V19 of TP19 become unknown,
Internal resistance R2a / R1b / R2b / R1c of Hall element
Cannot be directly obtained. Therefore, (V1a) = (V2a) and (V1c) = (V2a
c), and the unknown potentials V1b and V2b shown above among the internal resistances of the Hall element are determined from the following calculation.

(V1b) = (V16a) − (V16b) − (V1a) (V2b) = (V16b) − (V16c) − (V2c) Here, (V1b) and (V2b) are compared, and the internal resistance R1
If it is confirmed that the voltages applied to b and R2b are equal,
It can be determined that the input-side internal resistances of the three Hall elements are normal. In the above formulas (V1b) and (V2b),
Potentials V1a and V2c applied to internal resistances R1a and R2c
And (V1a) = (V2a) and (V1a)
Since it is assumed that 1c) = (V2c), if there is an abnormality in any of the internal resistances R1a, R2a, R1c, and R2c, the above formula is affected and (V1b) = (V2b).
It is because it does not become. However, when a plurality of internal resistances are abnormal at the same ratio at the same time, it may be determined that they are normal. However, such a situation can be ignored because it is extremely low in terms of probability. Further, in this method, no matter which Hall element is abnormal, (V1b) ≠
(V2b), the abnormal Hall element cannot be specified. Abnormalities Although there are some problems as described, the purpose of enabling detection of defects in and around the Hall element in the brushless motor can be achieved. (Embodiment 4) An embodiment of the invention described in claim 8 of the present invention will be described below with reference to FIG.

FIG. 4 shows an equivalent circuit of a winding coil section in a brushless motor according to an eighth aspect of the present invention and an inspection circuit according to the present invention. In FIG. 4, among three phases composed of a plurality of winding coils, an A-phase winding coil 22, a B-phase winding coil 23, and a C-phase winding coil 24 are connected at one terminal, respectively. One terminal 25, 26,
27 is connectable to a motor drive circuit, TP28, 29, 30
Is arranged.

For example, in a three-phase full-wave brushless motor in which the power supply voltage supplied to the brushless motor is 6 V,
In order to obtain 1 A of supplied current, the total resistance value of the winding coil per phase must be 3Ω or less. From ± 5%, which is the permissible variation in the resistance value of the winding coil between phases in a general brushless motor, if the A phase is 3Ω, the B and C phases must be in the range of 2.85 to 3.15Ω. There is. Measurement error of normally available resistance meter is ± 0.1Ω
From 20 ° C. to 10 ° C. depending on the temperature characteristic of the specific resistance of copper.
It can be seen that the above-mentioned inspection is difficult because, for example, a change of 0.1 ° C. when the temperature changes by 0.1 ° C., and a variation of about 0.1 Ω is expected in the contact resistance of the measurement terminal with the TP.

In the brushless motor having such a winding coil, TP30 is set to GND, and 1 V is applied to TP28.
Is applied to measure the potential V29 of TP29. For example, when the resistance value of each phase is 3Ω and there is no relative difference, the potential V29
Is 500 mV, and it can be determined that there is no problem. When the resistance value of the C phase is 2.85Ω, V29 becomes 487 mV, and a difference of 0.15Ω in the resistance value is detected as a difference of 13 mV in the voltage value. Thus, it can be easily determined that the resistance value of the C phase is 5% smaller than that of the A phase. However, since the B phase cannot be inspected in the above inspection, the measurement is performed in the same manner by switching between the voltage application and the potential measurement TP. Further, although the relative difference between the resistance values of the winding coils of each phase can be checked, there is a problem that the absolute value of the resistance is unknown. However, in a winding coil of a normal brushless motor, since a wire having a wire diameter within a standard range is wound in the set number of turns, there are few cases where the absolute value of the resistance value becomes a problem. (Embodiment 5) An embodiment of the invention described in claim 9 of the present invention will be described below with reference to FIG.

FIG. 5 shows an equivalent circuit of a winding coil part in a brushless motor according to a ninth embodiment of the present invention and an inspection circuit according to the present invention. In FIG. 5, among three phases composed of a plurality of winding coils, an A-phase winding coil 22, a B-phase winding coil 23, and a C-phase winding coil 24 are connected at one terminal, respectively. One terminal 25, 26,
27 is connectable to a motor drive circuit, TP28, 29, 30
Is arranged. TP30 is set to GND via a resistor R5, TP28 is applied with 1V via a resistor R5 having a predetermined resistance value, and TP29 is connected to a resistor R5 via a relay element 21 to make GND. In this state, first, the relay element 21
Is turned OFF, and the potential V29 of TP29 is measured. When the resistance R5 is 3Ω and the resistance value of each phase is 3Ω, the potential V29 becomes 500 mV.

Here, when the resistance value of the C phase is 2.85Ω, the potential V29 becomes 494 mV, and the difference of 0.15Ω in the resistance value is detected as the difference of 6 mV in the voltage value.
Resistance value defects can be detected. However, since the absolute value of the winding coil of each phase is unknown only by this, the potentials of TP30 and TP28 are measured, and the voltage VR applied to the resistor 5, the voltage VA applied to the A phase, and the voltage VC applied to the C phase are calculated. Compare. If the voltages VR and VC are the same, the resistance value of the resistor R5 is 3Ω, so that the resistance value of the C phase is also 3Ω. For example, when only the C phase is 2.85Ω, the voltage VR = 253 mV and the voltage value applied to 3Ω are found, and the voltage VA is 2
It was confirmed that the resistance value of the A phase was 3Ω at 53 mV,
When the voltage VC is 241 mV and the resistance value of the C phase is 2.85Ω (=
[241/253] * 3).

Next, by turning on the relay element 21, the resistance value of the B phase can be inspected as described in the second embodiment. However, the calculation becomes complicated, and the inspection accuracy is inferior to the case where the relay element 21 is turned off. Therefore, when the resistance value of the winding coil is further reduced and a more precise inspection is required, Inspection should be performed by switching the voltage application TP. (Embodiment 6) An embodiment of the present invention described in claims 10 to 12 of the present invention will be described below with reference to FIG.

FIG. 6 shows an equivalent circuit and an inspection circuit of the winding coil portion of the brushless motor according to the present invention. FIG.
Of the three phases composed of a plurality of winding coils,
Phaseless winding coil 22, B-phase winding coil 23, and C-phase winding coil 24 are connected at one terminal respectively, and the other terminals 25, 26, 27 are connectable to a motor drive circuit. In the motor, TPs 28, 29, and 30 are arranged near each terminal. Further, a TP31 for additionally inspecting the resistance value of one of the winding coils of the C phase or a part of the wire constituting the winding coil is additionally provided. As a result, the resistance of the wound coil changes depending on the wire diameter of the winding material, so that even if the resistance is the same, the problem that the number of turns is not normal can be inspected.

As shown in FIG. 6, when the number of winding coils per phase is two, the resistance value of one winding coil is 1.5.
Ω and the voltage VZ (TP31 and 3
The potential difference between 0) is 125 mV. That is, when the number of turns of the regular winding coil is 80 turns, the resistance value of the 80-turn winding coil using a wire having a predetermined wire diameter is 1.5Ω.
, And the voltage VZ becomes 125 mV in the inspection circuit.
Naturally, as the wire diameter decreases, the resistance value of the winding coil increases, and the voltage VZ also increases. Here, 2 of C phase
If the voltage VC applied to one winding coil is 250 mV, the voltage applied to another winding coil of phase C is 125 mV.
mV, indicating that the number of turns is the same. For example, the voltage VC is 240.5 mV and the voltage VZ is 126.5 m
In the case of a measurement result such as V, the voltage applied to another winding coil of the C phase is 114 mV, and the number of windings of the winding coil is 72 turns (= [114 / 126.5] × 80), which is 8 turns. That is, there is a difference. This is a problem that leads to uneven rotation and vibration as a brushless motor, but the resistance value of the C phase is 2.85Ω (= [24
0.5 / 126.5] × 1.5), which is determined to be normal by the conventional brushless motor inspection method. These problems are thought to be unlikely to occur as long as they are manufactured with the specified number of turns,
This is a problem from a quality control perspective where you do not know what will happen. The above description utilizes the fact that the number of windings and the resistance value change at a fixed rate because all the winding coils used in one brushless motor use the same rod material. A change in the resistance value cannot be detected even with the same number of turns caused by different wire diameters. In fact, it is rare to incorporate winding coils using wires with different wire diameters with a single brushless motor.
At the same time, it is probable that the wrong number of turns overlaps. Furthermore, in order to confirm the number of turns of each winding coil in this way, it is necessary to measure the voltage applied to all winding coils.However, by verifying the ratio of the measurement results, the voltage applied to each phase can be determined. By measuring the voltage applied to one winding coil, it is possible to determine that there is an abnormality even if it is not possible to specify which winding coil.

In a brushless motor in which a winding coil is formed by a copper pattern on a printed circuit board, it is assumed that the number of turns of the winding coil is reduced due to a pattern short. In such a case, the means for checking the number of turns described above is very effective. In addition, since the cross-sectional area of the copper pattern is usually constant within the same printed circuit board, the same effect can be obtained by measuring the voltage applied to the copper pattern in a certain section other than the winding coil. Can be expected.

Next, the relay element 21 shown in FIG.
In this manner, the resistance value of the coil of each phase can be inspected in the same manner as described in the second embodiment. That is, T
By connecting the relay 21 to GND via a resistor R5 having a predetermined resistance value and connecting the relay P21 to the GND and comparing the potential of the coil middle point VC when the relay 21 is turned on and off to the potential of the TP29, The resistance value of the coil can be inspected. The resistance values of the other phases can be checked similarly.

In the inspection described above, the degree to which the inspection is required is determined by the accuracy required for the brushless motor. However, the brushless motor is required to be further downsized and to be driven at a lower voltage. In such situations, the resistance value and the number of turns of the wound coil are further reduced, and the influence of the failure of the wound coil tends to appear on the motor performance. It is thought that there will be more opportunities.

The contents described in the first to sixth embodiments relate to parts and products in which the resistance value of the object to be inspected is small or the change in resistance value due to a defect is relatively small with respect to the width of the resistance value standard. In the above, means for performing high-precision inspection is provided. Such inspections can be performed not only for brushless motors, but also for inspections of many parts and products, such as shipment inspections of single Hall elements and shipment inspections of printed circuit boards. This enables cost reduction.

In the above description, the inspection method is performed in a state where the terminals of the tachogenerator, the hall element, and the winding coil are isolated from another circuit (motor drive circuit). In this case, the measurement results are not the same as those described above, and the measurement accuracy is poor, but the inspection itself is often possible. Furthermore, by combining with the inspection of the tachogenerator, the Hall element, and the winding coil, it is also possible to simultaneously perform an inspection for a short circuit in each component and its surroundings, further shortening the inspection time. .

In the above description, TP is used to measure a potential and apply a voltage. In order to detect a potential by bringing a test probe into contact with the TP, a TP pattern as shown in FIGS. Although shown, even if a specific TP pattern is not necessarily formed, a part to be soldered or a part of the copper pattern can be made conductive to form a TP part, or a part of the copper pattern on the printed circuit board can be slightly changed. It is also possible to form a land part by enlarging to a TP part.

The parts shown in the embodiment are made conductive parts such as a terminal for connection to a motor drive circuit, a part to which terminals of a winding coil and a Hall element are soldered,
Further, a portion from which the insulating film is removed to enable conduction of a part of the copper pattern of the printed circuit board can be used as the TP. However, when a terminal for connecting to the motor drive circuit is used, a trace may be left on the terminal, which may cause a connection failure to the motor drive circuit by a connector or the like. In addition, if the part to which the terminals of the winding coil and the Hall element are soldered is used, conduction failure due to solder failure when soldering the terminal of the winding coil and the Hall element is conducted when the test pin is brought into contact. There is a possibility that the defect is determined to be OK. Furthermore, when the insulating film is removed to enable conduction of a part of the copper pattern of the printed circuit board, the insulating film is removed and the portion is used as a substitute for the TP because the insulating film is removed because it is close to other members of the brushless motor. It is likely to be short. Conversely, if the portion where the insulating film is removed and used as a substitute for the TP is to be separated from other members of the brushless motor, the copper pattern designed to exhibit the performance of the brushless motor is deformed. As a result, the performance of the brushless motor may be affected.

However, in the case where the brushless motor is further downsized and it is difficult to take up space for disposing the TP, the above-mentioned one is used instead of the TP. Further, when removing the insulating film from a part of the copper pattern of the printed circuit board, by increasing the area of the copper pattern at the part, the conduction during the inspection can be stabilized. However, in the conventional inspection based on the resistance value, it is not necessary to increase the area of the conductive portion for the inspection due to, for example, a four-point method for accurate measurement. Will be able to secure.

[0061]

As described above, according to the method for inspecting a tachogenerator of a brushless motor and a brushless motor of the present invention, a problem such as a short circuit or disconnection in a tachogenerator, a hall element, a winding coil itself and its surroundings can be detected. Thus, the detection can be performed accurately and reliably at a low cost.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram of a tacho generator and an inspection circuit of a brushless motor according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining an equivalent circuit and an inspection method of a position detection element of a brushless motor according to a second embodiment of the present invention.

FIG. 3 is a view for explaining an equivalent circuit in which three position detecting elements of a brushless motor are connected in series and an inspection method according to a third embodiment of the present invention;

FIG. 4 is a diagram for explaining an equivalent circuit and an inspection method of a winding coil in an inspection method of a winding coil of a brushless motor according to a fourth embodiment of the present invention.

FIG. 5 is a diagram for explaining an equivalent circuit and an inspection method of a winding coil in an inspection method of a winding coil of a brushless motor according to a fifth embodiment of the present invention.

FIG. 6 is a diagram for explaining a method of inspecting a wound coil according to a sixth embodiment of the present invention;

FIG. 7 is a view for explaining a main part of a tachogenerator of a brushless motor according to a conventional embodiment.

FIG. 8 is an equivalent circuit diagram of a position detecting element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Printed circuit board 2 Tach generator 3 Terminal connected to the drive circuit provided at the start of tach generator 4 Terminal connected to drive circuit provided at the end of tach generator 5 Test point provided at the start of tach generator 6 Tach A test point provided at the end of the generator 7 A point at which the pattern of the tachogenerator is divided by a distance of 1: 3 8 A test point provided near point 7 9 Intersection points 10 and 11 in an equivalent circuit of a position detection element (Hall element) Input terminal of detection element (Hall element) 12, 13 Output terminal of position detection element (Hall element) 14, 15, 16, 17 Position detection element (Hall element)
Test points 18 and 19 provided at each of the terminals 18 and 19 Test points 21 arranged between the input terminals of the position detecting elements (Hall elements) arranged in series 21 Relay element 22 A-phase winding coil 23 B-phase Winding coil 24 C-phase winding coil 25 A-phase terminal connected to motor drive circuit 26 B-phase terminal connected to motor drive circuit 27 C-phase terminal connected to motor drive circuit 28 Terminal 25 Connected test point 29 Test point connected to terminal 26 30 Test point connected to terminal 27 31 Test point for measuring voltage applied to one winding coil

Claims (12)

[Claims] 1. A brushless motor having a stator having a multi-phase winding coil facing a rotor having a permanent magnet having a plurality of magnetic pole pairs, the brushless motor being fixed to the stator facing the permanent magnet of the rotor. A tachogenerator for generating a signal for controlling the speed by forming a wave winding by means of a conductive pattern on a printed circuit board, wherein at least three or more test points are provided from the beginning, the end and the middle of the wave winding. And a short-circuit state of the conductive pattern of the wave winding is detected. 2. The method according to claim 1, wherein the at least one test point disposed between the start and end of the wave winding has a line length of approximately 1: 3 with respect to the line length from the start to end of the wave winding. The tachogenerator of a brushless motor according to claim 1, wherein the tachogenerator is drawn from a portion divided by a ratio. 3. The brushless motor tacho generator according to claim 1, wherein a part or all of the test points can be pulled out and connected to the outside by a connector or the like instead of arranging the test points. 4. A brushless motor having a stator having a multi-phase winding coil facing a rotor having a permanent magnet having a plurality of magnetic pole pairs, the brushless motor being fixed to the stator facing the permanent magnet of the rotor. A tachogenerator for generating a signal for controlling the speed by forming a wave winding by means of a conductive pattern on a printed circuit board, wherein at least three or more test points are provided from the beginning, the end and the middle of the wave winding. And a predetermined voltage is applied to one of the beginning and end of the wave winding, and the other is GND.
Testing the tachogenerator of the brushless motor, wherein the short circuit state of the conductive pattern forming the wave winding is detected by measuring the potential of a test point disposed in the middle of the wave winding in the state of Method. 5. A brushless motor having a stator having a multi-phase winding coil opposed to a rotor having a permanent magnet having a plurality of magnetic pole pairs, for detecting a position of the permanent magnet of the rotor. A position detecting element is soldered on a printed circuit board fixed to the stator, test points are arranged on two pairs of terminals of the position detecting element, and a test point is provided at one end of the pair of terminals of the position detecting element. Apply a predetermined voltage and set the other end to GND, measure the potential of a test point disposed on another pair of non-voltage application terminals of the position detection element, and then change the voltage application terminal pair. A brushless motor for measuring the potential of a test point and comparing the measured potential values to check for destruction of the position detecting element and short-circuiting around the position detecting element. Inspection method for position detecting element. 6. The brushless motor position detecting element according to claim 5, wherein a part or all of the test points can be pulled out and connected to the outside by a connector or the like instead of arranging the test points. Inspection methods. 7. A brushless motor having a stator having a multi-phase winding coil facing a rotor having a permanent magnet having a plurality of magnetic pole pairs, for detecting a position of the permanent magnet of the rotor. A plurality of position detection elements are connected in series and arranged, a predetermined voltage is applied to one end of the input side terminal pair of the position detection elements arranged in series, the other end is set to GND, and the position detection element is Connect a resistor with a predetermined resistance value to all output side terminal pairs via a relay element and connect to GND.
Terminals, the potential of each pair of test points arranged at the output side terminal of each of the position detecting elements is measured when the relay is turned on and when the relay is turned off, and the measured potential value is determined by a predetermined value. By performing arithmetic processing,
A method for inspecting a position detecting element of a brushless motor, wherein destruction of the position detecting element and a short state around the position detecting element can be inspected. 8. A three-phase brushless motor having a stator having a winding coil having a resistance value per phase of about 5Ω or less, facing a rotor having a permanent magnet having a plurality of magnetic pole pairs. A test point is arranged on each side of the winding coil connected to the motor drive circuit, and
Apply a predetermined voltage to the test points of the phase, set the test points of the other phases to GND, measure the potentials of the test points of the remaining phases, then change the voltage applied test points, and A method for inspecting a winding coil of a three-phase brushless motor, comprising measuring an electric potential and inspecting a short circuit in the winding coil and a short circuit around the coil. 9. A three-phase brushless motor having a stator having a winding coil having a resistance per phase of about 5Ω or less, facing a rotor having a permanent magnet having a plurality of magnetic pole pairs. A test point is arranged on each side of the winding coil connected to the motor drive circuit.
A predetermined voltage is applied to a test point of one of the phases via a resistor having a predetermined resistance value, and a test point of one of the other phases is connected to a GND via a predetermined resistance value. The potential of each test point is measured, then the voltage application test point is replaced, the potential of each test point is measured, and the potential measurement value is subjected to a predetermined arithmetic processing, thereby obtaining the winding. A method for inspecting a winding coil of a brushless motor, wherein a resistance value of the coil can be inspected. 10. A three-phase brushless motor having a stator having a winding coil having a resistance per phase of about 5Ω or less, facing a rotor having a permanent magnet having a plurality of magnetic pole pairs. A test point is arranged on each side of the winding coil connected to the motor drive circuit, and further arranged between a plurality of winding coils constituting each phase or at a position where a conductive pattern forming the winding coil is divided. At least one or more test points are arranged, a predetermined voltage is applied to the test point connected to the one-phase motor drive circuit, and a predetermined voltage is applied to the test point connected to the other phase motor drive circuit. The test point is set to GND, the potentials of the test points are measured, and the measured potential values are subjected to a predetermined arithmetic processing to determine the number of turns of the winding coil. Inspection method of winding coils of the brushless motor, characterized in that to enable checking the condition. 11. The method according to claim 9, wherein the arithmetic processing includes a subtraction processing and a comparison processing. 12. The apparatus according to claim 8, wherein a part or all of the test points can be pulled out and connected to the outside by a connector or the like instead of arranging the test points. Inspection method of wound coil of brushless motor.