JPH11356024A - Brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent magnetism detecting elements from being adversely affected by magnetic fields, by separating in the circumferential direction a region on a circuit board where driving current carrying terminals are placed from a region on the circuit board where the magnetism detecting elements are placed so that these regions do not interfere with each other. SOLUTION: Terminals Tu, Tv, Tw for feeding are placed around an output shaft 9 at intervals of 40 deg., and are positioned in a first region A1 within 80 deg.. Three Hall elements 17u, 17v, 17w as magnetism detecting elements are placed on a circuit board 13 in proximity to the circumference of a sensor magnet 12. The Hall elements are placed around the output shaft 9 at intervals of 80 deg. and are positioned in a second region A2 within 160 deg.. The one 17u of the three Hall elements placed in the center and the one Tv of the terminals Tu, Tv, Tw for feeding placed in the center are positioned on one and the same straight line running the center of the output shaft 9. As a result, it is possible to prevent the magnetism detecting elements from being adversely affected by magnetic fields generated by driving currents.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor, and more particularly, to a brushless motor used as a blower motor of a vehicle air conditioner.

[0002]

2. Description of the Related Art As one type of brushless motor used as a motor for a blower of a vehicle air conditioner, there is one described in, for example, JP-A-9-191625.
In this brushless motor, a stator having an excitation coil and a control board are fixed to an upper case member constituting a case housing, and the control board is provided with an excitation circuit for generating a rotating magnetic field in the stator. I have.

[0003] Three input terminals for power supply are connected to the excitation coil. The input terminals are arranged at intervals of 120 ° about the rotation axis, and extend under the control board through a through hole formed in the control board. Further, the control board is provided with three output terminals of the excitation circuit. Each output terminal extends below the control board. The output terminal and the input terminal are bridged by an intermediate terminal that is arranged so as to float from the control board.

[0004] A rotor is rotatably supported on the stator by a rotating shaft. The rotor has a boss portion fixed to the rotating shaft, an umbrella portion extending in an umbrella shape from the boss portion, a cylindrical portion extending downward from the outermost peripheral edge of the umbrella portion, and an inner peripheral side surface of the cylindrical portion. , And a plurality of permanent magnets arranged at the same time. A fan is fixed to the upper end of the rotating shaft so as to rotate integrally. Further, a disc-shaped sensor magnet for detecting the rotation angle of the rotor (the position of the permanent magnet) is fixed to the lower end of the rotating shaft.

[0005] The control board is provided with a plurality of Hall elements near the outer periphery of the sensor magnet. Each Hall element detects a change in the magnetic field due to rotation of the sensor magnet, and outputs a detection signal to the excitation circuit.

The excitation circuit generates three-phase AC drive currents having different phases based on a DC power supply supplied from the outside, and supplies the drive current to an excitation coil via an output terminal, an intermediate terminal and an input terminal. To supply. At this time, the excitation circuit controls the phase of each drive current based on the detection signal from each Hall element so that the rotation angle of the rotor and the timing for exciting the excitation coil are optimized.

When each drive current is supplied to the exciting coil of the stator, a rotating magnetic field is generated in the stator, and the rotor is driven to rotate based on the rotating magnetic field. With the rotation of the rotor, the fan is rotated to perform a blowing operation.

[0008]

When the rotor permanent magnet has four poles, the sensor magnet 20 also has four poles, as shown in FIG. 11, and has an N pole and an S pole. Are provided alternately at every 90 °.
Further, in this case, it is necessary to detect the rotation angle of the rotor every 30 ° in order to control the three-phase excitation circuit.

Therefore, the three Hall elements 21u, 21
v, 21w are used, and the Hall elements 21u, 21v, 21w are arranged on the control board at 120 ° intervals about the rotation shaft 22. On the other hand, the input terminals 23u, 23v, and 23w for supplying a drive current to the excitation coil are also arranged at intervals of 120 ° about the rotation shaft 22, so that the Hall elements 21u, 21v, and 21w and the input terminals 23u and 23v. , 23w are alternately arranged in the circumferential direction.

If the permanent magnet of the rotor has six poles, the sensor magnet 20a also has six poles as shown in FIG.
It is provided alternately every °. Further, in this case, it is necessary to detect the rotation angle of the rotor every 20 ° in order to control the three-phase excitation circuit.

Therefore, the three Hall elements 21u, 21
v, 21w are used, and FIG.
As shown in (a), each Hall element 21u, 21v, 21
w are arranged at 140 ° intervals around the rotation axis 22 or, as shown in FIG.
1 v and 21 w are arranged at 100 ° intervals about the rotation shaft 22. On the other hand, the input terminals 23u, 23v, and 23w for supplying a drive current to the excitation coil are similarly arranged at 120 ° intervals about the rotation shaft 22, so that the Hall elements 21u, 21v, and 21w and the input terminals 23u and 23w.
v and 23w are alternately arranged in the circumferential direction.

In FIG. 11 and FIG. 12, when a drive current flows through the input terminals 23u, 23v, 23w, a magnetic field is generated around the terminals 23u, 23v, 23w, and the Hall elements 21u, 21v, 23v, 23w. 21w may erroneously detect this intersecting magnetic field as a change in the magnetic field due to the rotation of the sensor magnets 20, 20a. in this way,
Each of the Hall elements 21u, 21v, 21w is connected to a terminal 23u, 2
If the current magnetic field generated around 3v, 23w is erroneously detected,
A deviation occurs between the rotation angle of the rotor (the position of the permanent magnet) and the timing for exciting the exciting coil. Such a deviation increases the torque ripple, causing a problem that the output of the motor decreases, a problem that vibration and noise are generated, and the like.

In the case of downsizing the motor,
Hall elements 21u, 21v, 21w and input terminals 23u,
Since 23v and 23w are close to each other, the Hall elements 21u,
If the terminals 21v, 21w and the input terminals 23u, 23v, 23w are alternately arranged in the circumferential direction, the above problem may further occur. Therefore, the above arrangement hinders downsizing of the motor.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a brushless device provided with a magnetic detecting element for detecting a sensor magnet rotating with a rotor and detecting a rotation angle of the rotor. An object of the present invention is to provide a brushless motor in which a magnetic detection element is less likely to be adversely affected by a magnetic field generated by a driving current without hindering downsizing of the motor.

[0015]

In order to solve the above-mentioned problems, the invention according to claim 1 provides an exciter coil having a plurality of phases on a stator, rotatably supports a rotor, and attaches a sensor magnet to the rotor. Attached so that it can rotate integrally,
A plurality of magnetic detection elements for detecting a change in the magnetic field by the sensor magnet and detecting a rotation angle of the rotor are provided on a circuit board in a position near the sensor magnet, and the circuit board and the excitation coils of each phase are provided. And a driving current corresponding to the exciting coil of each phase is supplied to the exciting coil via the terminal to rotate the rotor, and the magnetic detecting element In a brushless motor that controls each of the drive currents based on detection of a rotation angle of the rotor, a first region on the circuit board where terminals for the respective drive currents are arranged, and the magnetic detection elements are arranged. The gist is that the set second region is separated in the circumferential direction so as not to interfere with each other.

According to a second aspect of the present invention, in the brushless motor according to the first aspect, the first area is an area within 180 ° with respect to the rotation center of the rotor, and the second area is The gist of the present invention is that the region is set within 180 ° on the opposite side to the first region with respect to the rotation center of the rotor.

According to a third aspect of the present invention, there is provided the first or second aspect.
3. The brushless motor according to claim 1, wherein the first and second
With respect to a straight line passing through the center in the circumferential direction in the region and the rotation center of the rotor, the respective terminals are arranged symmetrically in the first region, and the respective magnetic sensing elements are arranged symmetrically in the second region. The gist is that you have done it.

According to a fourth aspect of the present invention, in the brushless motor according to any one of the first to third aspects, the exciting coil provided on the stator is a three-phase exciting coil, and the rotor has six poles. And the sensor magnet has six poles corresponding to the magnets of the rotor and each pole has six poles.
The gist is provided at every 0 °, and the magnetic detecting element includes three elements, and each element is arranged at intervals of 40 ° or 80 ° with respect to the rotation center of the rotor.

According to a fifth aspect of the present invention, in the brushless motor according to any one of the first to third aspects, the exciting coil provided on the stator is a three-phase exciting coil, and the rotor has four poles. And the sensor magnet has four poles corresponding to the magnets of the rotor and each pole has nine poles.
The gist is provided at every 0 °, and the magnetic detecting element is composed of three elements, and each element is arranged at an interval of 60 ° with respect to the rotation center of the rotor.

Therefore, according to the first aspect of the present invention,
On the circuit board, the first region where the terminals through which the respective drive currents flow is arranged and the second region where the respective magnetic sensing elements are arranged are separated in the circumferential direction so as not to interfere with each other. Therefore, even if a drive current flows through each terminal and a magnetic field is generated around the terminal, the magnetic sensing element and the terminal are separated without being alternately arranged in the circumferential direction.
The magnetic detection element is less likely to be adversely affected by the magnetic field generated at the terminal. Therefore, this does not hinder downsizing of the motor.

According to the second aspect of the present invention, the first region is a region within 180 ° with respect to the rotation center of the rotor, and the second region is the first region with respect to the rotation center of the rotor. And within 180 ° on the opposite side. Therefore, the same operation and effect as those of the first aspect can be obtained.

According to the third aspect of the present invention, the terminals are arranged symmetrically in the first region with respect to a straight line passing through the circumferential center in the first and second regions and the rotation center of the rotor. In the second area, the respective magnetic sensing elements are arranged in contrast. Therefore, the terminal arranged at the end in the first region and the magnetic detecting element arranged at the end in the second region are less likely to interfere with each other, and the magnetic detecting element is generated at the terminal. It is less likely to be affected by the magnetic field.

According to the fourth aspect of the present invention, the exciting coil provided on the stator is a three-phase exciting coil,
The rotor is provided with a magnet composed of six poles, the sensor magnet is composed of six poles corresponding to the magnet of the rotor, and each pole is provided every 60 °. The magnetic detection element is composed of three elements, and each element is arranged at intervals of 40 ° or 80 ° with respect to the rotation center of the rotor. Here, when the rotor magnet has six poles with respect to the three-phase excitation coil, it is necessary to detect the rotation angle of the rotor every 20 ° for motor control. Therefore, the sensor magnet is composed of six poles corresponding to the magnet of the rotor, and each pole is provided at every 60 °, and three magnetic detecting elements are provided for the sensor magnet at 40 ° with respect to the rotation center of the rotor. By arranging them at intervals or at intervals of 80 °, the rotation angle of the rotor can be detected by the magnetic detection element every 20 °.

According to the invention described in claim 5, the excitation coil provided on the stator is a three-phase excitation coil,
The rotor is provided with a magnet composed of four poles, and the sensor magnet is composed of four poles corresponding to the magnet of the rotor, and each pole is provided at every 90 °. The magnetic detecting element is composed of three elements, and each element is arranged at intervals of 60 ° with respect to the center of rotation of the rotor. Here, when the rotor magnet has four poles with respect to the three-phase excitation coil, the rotation angle of the rotor is set to 30 ° for motor control.
It is necessary to detect each time. Therefore, the sensor magnet is composed of four poles corresponding to the magnets of the rotor, and each pole is provided at every 90 °.
By arranging at 0 ° intervals, the rotation angle of the rotor can be detected by the magnetic detection element every 30 °.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a brushless motor used as a blower motor of a vehicle air conditioner. A stator 2 is fixed to an upper surface of the motor holder 1. The stator 2 includes a center piece 3 and
It includes a core 4 and U-phase, V-phase, and W-phase excitation coils 5u, 5v, and 5w each formed by winding a winding 5 around the core 4. In the center of the core 4, power supply terminals as three terminals for power supply, that is, U-phase, V-phase, and W-phase power supply terminals T
The base ends of u, Tv and Tw are press-fitted, and the front ends thereof are directed downward. The terminals of the respective exciting coils 5u, 5v, 5w are crimped to the respective power supply terminals Tu, Tv, Tw, and the terminals Tu, Tv, Tw are electrically connected to the respective exciting coils 5u, 5v, 5w. .

As shown in FIG. 3, slots 4a are formed in the core 4 at equal intervals at 18 places. The numbers in FIG. 3 indicate slot numbers, and the numbers are sequentially added in a counterclockwise direction. Then, the U-phase power supply terminal Tu is supported between the slot numbers “17” and “18”, and the V-phase power supply terminal Tv is supported by the slot numbers “1” and “2”.
, And the W-phase power supply terminal Tw is supported between the slot numbers “3” and “4”. That is, the power supply terminals Tu, Tv, Tw are arranged at intervals of 40 ° around an output shaft 9 described later as shown in FIG.
Are arranged in an area A1 as a first area.

Incidentally, the U-phase excitation coil 5u is
As shown in (a), the winding 5 moves from the U-phase power supply terminal Tu to W
Toward the phase power supply terminal Tw, the slot number “1 → 4 →
7 → 10 → 13 → 16 → 1 → 4 ”in a distributed winding manner around the slot 4a. As shown in FIG. 4B, the V-phase excitation coil 5v has a winding number 5 from the V-phase power supply terminal Tv toward the U-phase power supply terminal Tu, where the slot number is “3 → 6 → 9 → 12 →”. 15 → 18 → 3 → 18 ”in a distributed winding manner around the slot 4a. As shown in FIG. 4C, the W-phase excitation coil 5w is configured such that the winding 5 is moved from the W-phase power supply terminal Tw to the V-phase power supply terminal Tv.
Toward slot number “5 → 8 → 11 → 14 → 17”
→ 2 → 5 → 2 ”in a distributed winding manner around the slot 4a.

A rotor 6 is rotatably supported by the stator 2. The rotor 6 includes a bell-shaped yoke 7, a magnet 8 fixed to the inner peripheral surface of the yoke 7 and having six poles, and an output shaft 9 pressed into the center of the yoke 7. Then, the output shaft 9 is connected to the bearings 10a, 1
The centerpiece 3 is rotatably supported at the center of the centerpiece 3 via a base 0b, and a fan 11 is fixed to the upper end of the output shaft 9 thereof.

At the lower end of the output shaft 9, a disc-shaped sensor magnet 12 is fitted so as to be able to rotate integrally with the shaft 9. As shown in FIG. 5, the sensor magnet 12 has six poles as in the case of the magnet 8, and has N poles and S poles alternately provided every 60 °.

A circuit board 1 is provided on the lower surface of the motor holder 1.
The circuit board 13 is provided with an excitation circuit 15 for generating a rotating magnetic field in the stator 2. 1 and FIG.
As shown in FIG. 5, an arc-shaped through hole 13a for inserting the power supply terminals Tu, Tv, Tw and an insertion hole 13b for inserting the output shaft 9 are formed. or,
On the lower surface of the circuit board 13, the base ends of the connection terminals 16u, 16v, and 16w are soldered to three output terminals of the excitation circuit 15, respectively. Each connection terminal 16
u, 16v, 16w are connected to the respective power supply terminals T
u, Tv, and Tw are fitted, and each power supply terminal T
u, Tv, and Tw are electrically connected.

The circuit board 13 is provided with three Hall elements 17u, 17v and 17w as magnetic detecting elements near the outer periphery of the sensor magnet 12. The Hall elements 17u, 17v, 17w are connected to the respective power supply terminals T
u, Tv, and Tw are disposed on the opposite side of the through hole 13b with respect to the through hole 13b. Specifically, as shown in FIGS. 2 and 5, the rotation angle of the rotor 6 is changed every 20 degrees. In order to detect, a region A2 as a second region which is arranged at an interval of 80 ° around the output shaft 9 and is within 160 °
Are located in That is, in the present embodiment, the area A2 where the Hall elements 17u, 17v and 17w are arranged and the area A1 where the power supply terminals Tu, Tv and Tw are arranged are separated in the circumferential direction. . In the present embodiment, three Hall elements 17u, 17v, 17
The Hall element 17u disposed in the middle of w and the power supply terminal Tv disposed at the center of each of the power supply terminals Tu, Tv, Tw are disposed on the same straight line passing through the center of the output shaft 9. Each of the Hall elements 17u, 17v, and 17w detects a change in the magnetic field due to the rotation of the sensor magnet 12, and outputs a detection signal to the excitation circuit 15. Then, the circuit board 13 is covered with a lower case 18 attached to the motor holder 1.

FIG. 6 shows a specific configuration of the excitation circuit 15. The excitation circuit 15 of the present embodiment is a rectifier circuit of a three-phase full-wave rectification system. In order to generate a rotating magnetic field in the stator 2, the battery power supply B is converted to U-phase, V-phase, and W-phase AC drive currents. The drive current is supplied to the U-phase, V-phase, and W-phase excitation coils 5u, 5v, and 5w.

The excitation circuit 15 includes a driving circuit 15a,
And a control circuit 15b for controlling the drive circuit 15a. The drive circuit 15a includes six npn-type transistors (hereinafter simply referred to as transistors) Tr1 to Tr6,
A diode D connected between the collector and the emitter of each of the transistors Tr1 to Tr6. The transistors Tr1 and Tr2, the transistors Tr3 and Tr4, and the transistors Tr5 and Tr6 are respectively connected in series between the battery power supplies B.

The U-phase, V-phase and W-phase excitation coils 5u, 5
v and 5w are delta-connected. A node N1 between the emitter of the transistor Tr1 and the collector of the transistor Tr2 is connected to a node N2 between the U-phase excitation coil 5u and the W-phase excitation coil 5w. A node N3 between the emitter of the transistor Tr3 and the collector of the transistor Tr4 is connected to a node N4 between the U-phase excitation coil 5u and the V-phase excitation coil 5v. A node N5 between the emitter of the transistor Tr5 and the collector of the transistor Tr6 is connected to a node N6 between the V-phase excitation coil 5v and the W-phase excitation coil 5w. Control signals φ1 to φ6 from the control circuit 15b are input to the bases of the transistors Tr1 to Tr6, respectively.

The control circuit 15b includes the Hall elements 1
Detection signals from 7u, 17v, and 17w are input. Each of the Hall elements 17u, 17v, and 17w switches the detection signal from the L level to the H level when the detection site of the sensor magnet 12 changes from the S pole to the N pole, and changes the detection signal from the H level when the detection site changes from the N pole to the S pole. Switch to L level. By arranging the Hall elements 17u, 17v, 17w with respect to the sensor magnet 12 as described above, the Hall elements 17u, 17v, 17w are rotated every 20 ° as shown in FIG. Changes from the H level to the L level or from the L level to the H level.

The control circuit 15b is provided with each of the Hall elements 17
u, 17v, and 17w based on the rising edge and the falling edge of the detection signal.
Is detected at every 20 °. The control circuit 15b
Based on the detection of the rotation angle, control signals φ1 to φ6 as shown in FIG. 7 are generated. Each of the transistors Tr1 to
Tr6 is turned on / off based on the control signals φ1 to φ6, and the U-phase, V-phase, and W-phase excitation coils 5u, 5v, and 5w have U-phase and V-phases whose phases are delayed by 40 ° as shown in FIG.
Phase and W-phase AC drive currents are supplied.

In the brushless motor configured as described above, the U-phase, the V-phase, and the U-phase are output from the excitation circuit 15 through the power supply terminals Tu, Tv, Tw and the connection terminals 16u, 16v, 16w.
When the drive current is supplied to the W-phase excitation coils 5u, 5v, 5w, a rotating magnetic field is generated in the stator 2, and the rotor 6 is driven to rotate based on the rotating magnetic field. This rotor 6
The fan 11 is rotated with the rotation of, and the blowing operation is performed. Then, the excitation circuit 15 is connected to each of the Hall elements 1.
7u, 17v, and 17w, the rotation angle of the rotor 6 is detected by a detection signal based on the rotation of the sensor magnet 12, and the rotation angle of the rotor 6 and the excitation coils 5u, 5w are detected.
The drive current is controlled so that the timing for exciting v and 5w is optimized.

At this time, each of the Hall elements 17u, 17v,
17w and the power supply terminals Tu, T
Since the region A1 where v and Tw are arranged is separated from each other in the circumferential direction without interfering with each other, a drive current flows through the power supply terminals Tu, Tv and Tw, so that the terminals Tu, Tw and Tw are caused to flow. Of the Hall elements 17u, 17v,
17w is prevented from being erroneously detected.

As described above, this embodiment has the following features. (1) In the present embodiment, a region A on the circuit board 13 where the Hall elements 17u, 17v, and 17w are arranged
2 and the area A in which the power supply terminals Tu, Tv, Tw are arranged
1 were separated in the circumferential direction without interfering with each other. Therefore, even if a drive current flows through each of the terminals Tu, Tv, Tw and a magnetic field is generated around the terminals Tu, Tv, Tw,
Hall elements 17u, 17v, 17w and terminals Tu, Tv,
Tw is separated without being alternately arranged in the circumferential direction, so that the Hall elements 17u, 17v, 17w are less likely to be adversely affected by the magnetic field generated at the terminals Tu, Tv, Tw. Therefore, without hindering downsizing of the motor,
It is possible to prevent an increase in torque ripple due to erroneous detection of the hall elements 17u, 17v, 17w.

(2) Moreover, the Hall elements 17u, 17
Since v and 17w are less likely to be adversely affected by the magnetic field generated at the terminals Tu, Tv and Tw, the terminals Tu, Tv and Tw can be increased. As a result, each terminal Tu, Tv,
Since the allowable value of the driving current flowing through Tw can be increased, the output of the motor can be increased.

(3) In the present embodiment, the Hall element 17u arranged in the middle of the three Hall elements 17u, 17v and 17w and the center of each of the power supply terminals Tu, Tv and Tw are arranged. The power supply terminal Tv and the power supply terminal Tv are arranged on the same straight line passing through the center of the output shaft 9. In other words, for that straight line,
In the region A1, the terminals Tu, Tv, Tw are arranged in contrast, and in the region A2, the Hall elements 17u, 17v, 17
w is placed in the control. Therefore, the terminals Tu and Tw arranged at the ends in the area A1 and the Hall elements 17v and 17w arranged at the ends in the area A2 are less likely to interfere with each other, and the Hall elements 17v and 17w are connected to the terminals thereof. Tu, Tw
And is less susceptible to the adverse effects of the magnetic field generated by the magnetic field.

The embodiment of the present invention may be modified as follows. In the above embodiment, as shown in FIG. 5, in order to detect the rotation angle of the rotor 6 every 20 °, each Hall element 17
u, 17v, and 17w are arranged at intervals of 80 ° around the output shaft 9 and are arranged in an area A2 within 160 °, but as shown in FIG. 8, each of the Hall elements 17u, 17v, 1
7w may be arranged at intervals of 40 ° around the output shaft 9, and may be arranged in a region within 80 °. Also in this case, the rotation angle of the rotor 6 can be detected every 20 ° by the Hall elements 17u, 17v, and 17w.

In the above embodiment, the magnet 8 of the rotor 6 and the sensor magnet 12 are constituted by six poles.
The number of poles of the magnet is not limited to this. For example, the magnet 8 of the rotor 6 may have four poles, and the sensor magnet 12a may have four poles as shown in FIG. In this case, the sensor magnet 12a
Has N poles and S poles alternately provided at every 90 °.
Further, when the magnet 8 of the rotor 6 has four poles, the rotation angle of the rotor 6 needs to be detected at every 30 ° for the control of the excitation circuit, so that each of the Hall elements 17u, 17v, 17w is centered on the output shaft 9. Are arranged at 60 ° intervals as 1
It is arranged in an area within 20 °.

By the way, with the above configuration, FIG.
The rotation angle of the sensor magnet 12 is 30 ° as shown in FIG.
Each time, one of the detection signals of the Hall elements 17u, 17v, and 17w changes from the H level to the L level or from the L level to the H level. The control circuit 15b detects the rotation angle of the sensor magnet 12 every 30 ° based on the rising edge and the falling edge of the detection signals of the Hall elements 17u, 17v, 17w. Based on the detection of the rotation angle, the control circuit 15b
The control signals φ1 to φ6 shown in FIG. The transistors Tr1 to Tr6 are on / off controlled based on the control signals φ1 to φ6, and the U-phase, V-phase, and W-phase excitation coils 5
As shown in FIG. 10, U-, V-, and W-phase AC drive currents whose phases are delayed by 60 ° are supplied to u, 5v, and 5w. Then, a rotating magnetic field is generated in the stator 2, and the rotor 6 is driven to rotate based on the rotating magnetic field.

Even if the magnet 8 of the rotor 6 has four poles as described above, each of the Hall elements 17u, 17v, 17w
And the power supply terminals Tu, Tv, Tw can be separated and arranged in the circumferential direction without interfering with each other. Therefore, when a drive current flows through the power supply terminals Tu, Tv, Tw, the power supply terminals Tu, Tv, Tw are connected to the power supply terminals Tu, Tv, Tw. Even if a crossing magnetic field occurs around it,
Each Hall element 17u, 17v, 17
False detection of w is prevented.

In the above embodiment, the Hall elements 17u and 17u are used to detect a change in the magnetic field of the sensor magnet 12.
Although 17v and 17w are used, the present invention is not limited to this. For example, other magnetic detecting elements that can detect a change in a magnetic field, such as a magnetoresistive element, may be used.

In the above embodiment, the power supply terminals Tu, Tv, Tw are arranged in the area A1 within 80 ° around the output shaft 9 on the circuit board 13, and the Hall elements 17
Although u, 17v, and 17w are arranged in the area A2 within 160 ° around the output shaft 9, the present invention is not limited to this. For example, the area in which the power supply terminals Tu, Tv, and Tw are arranged is defined as the output shaft 9 Within 180 ° to the center of
The area where the Hall elements 17u, 17v and 17w are arranged may be an area within 180 ° opposite to the area where the power supply terminals Tu, Tv and Tw are arranged with respect to the center of the output shaft 9.

The technical ideas other than the claims that can be understood from the above embodiments will be described below together with their effects. (A) The brushless motor according to any one of claims 1 to 5, wherein the magnetic detection element is a Hall element. Even with such a configuration, even if a drive current flows through each terminal and a magnetic field is generated around the terminal, the Hall elements and the terminals are separated without being alternately arranged in the circumferential direction. The Hall element is less likely to be adversely affected by the magnetic field generated at the terminal. Therefore, this does not hinder downsizing of the motor.

[0049]

As described in detail above, according to the present invention,
In a brushless motor provided with a magnetic detection element that detects a sensor magnet rotating with the rotor and detects the rotation angle of the rotor, the magnetic detection element is less likely to be adversely affected by a magnetic field generated by a driving current without hindering downsizing of the motor. A brushless motor that can be used.

[Brief description of the drawings]

FIG. 1 is a sectional view of a brushless motor according to an embodiment.

FIG. 2 is a sectional view taken along line XX in FIG.

FIG. 3 is a plan view showing a core and a power supply terminal.

FIG. 4 is an explanatory diagram for explaining an electrical connection between a power supply terminal and an exciting coil.

FIG. 5 is an explanatory diagram for explaining an arrangement of a Hall element and a power supply terminal.

FIG. 6 is a specific configuration diagram showing an excitation circuit.

FIG. 7 is a waveform chart showing the operation of the excitation circuit.

FIG. 8 is an explanatory diagram for explaining an arrangement of a Hall element and a power supply terminal in another example.

FIG. 9 is an explanatory diagram for explaining an arrangement of a hall element and a power supply terminal in another example.

FIG. 10 is a waveform chart showing the operation of the excitation circuit.

FIG. 11 is an explanatory diagram for explaining a conventional arrangement of a Hall element and a power supply terminal.

FIG. 12 is an explanatory diagram for explaining a conventional arrangement of a hall element and a power supply terminal.

[Explanation of symbols]

2 ... stator, 5u, 5v, 5w ... excitation coil, 6 ... rotor, 8 ... magnet, 12 ... sensor magnet, 13
... Circuit board, 17u, 17v, 17w ... Hall element as magnetic detecting element, A1 ... area as first area, A
2 ... Area as a second area, Tu, Tv, Tw ... Terminals as power supply terminals.

Claims (5)

[Claims] An exciting coil (5u, 5v, 5w) having a plurality of phases is provided on a stator (2), a rotor (6) is rotatably supported, and a sensor magnet (12) is integrally rotated with the rotor (6). A plurality of magnetic sensing elements (17) that are attached as possible and detect a change in the magnetic field by the sensor magnet (12) to detect the rotation angle of the rotor (6).
u, 17v, 17w) with the sensor magnet (12)
Are arranged on a circuit board (13) in the vicinity of the circuit board (13), and the exciting coils of the respective phases and (5u, 5v, 5
w) are electrically connected to each other, and drive currents corresponding to the exciting coils (5u, 5v, 5w) of the respective phases are supplied to the terminals (Tu, Tv, Tw). Supply to the excitation coils (5u, 5v, 5w) via the motor to rotate the rotor (6), and to detect the rotation angle of the rotor (6) by the magnetic detecting elements (17u, 17v, 17w). A first area (A1) on the circuit board (13), on which terminals (Tu, Tv, Tw) through which the respective drive currents flow are arranged, wherein
And a second area (A2) in which the magnetic detection elements (17u, 17v, 17w) are arranged, which are separated in a circumferential direction so as not to interfere with each other. 2. The brushless motor according to claim 1, wherein the first region (A1) is a region within 180 ° with respect to a rotation center of the rotor (6), and the second region (A2) ) Is a region within 180 ° opposite to the first region with respect to the rotation center of the rotor (6). 3. The brushless motor according to claim 1, wherein a straight line passing through a center in a circumferential direction in the first and second regions (A1, A2) and a rotation center of the rotor (6). In the first area (A1), each terminal (Tu, Tv, T
A brushless motor characterized in that w) is arranged symmetrically and each magnetic detection element (17u, 17v, 17w) is arranged symmetrically in the second area (A2). 4. The brushless motor according to claim 1, wherein the exciting coils (5u, 5) are provided on the stator (2).
v, 5w) are three-phase excitation coils, the rotor (6) is provided with a magnet (8) having six poles, and the sensor magnet (12) is provided with the rotor (6). The magnetism detecting element (17u, 17v, 17w) is composed of three elements and each element (17u, 17v, 17w) are arranged at intervals of 40 ° or 80 ° with respect to the rotation center of the rotor (6). 5. The brushless motor according to claim 1, wherein the exciting coils (5u, 5) are provided on the stator (2).
v, 5w) are three-phase excitation coils, the rotor (6) is provided with a magnet (8) having four poles, and the sensor magnet (12) is provided with the rotor (6). ) And four poles are provided at every 90 ° corresponding to the magnet (8), and the magnetic detection element (17u, 17v, 17w) is composed of three elements, and each element (17u, 17u, 17v, 17w) are arranged at intervals of 60 ° with respect to the rotation center of the rotor (6).