JPH09308208A - Brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate variation in Hall voltage, produced by t e rotation ejecting elements of a rotor magnet, for higher reliability, by including a leakage magnetism intercepting section that is placed in a position close to the rotation detecting elements and is capable of separating magnetic forces different from each other produced by the rotor magnet. SOLUTION: In a brushless motor 1, the rotor magnet 17 contained in its rotor 4 generates magnetic force to rotation detecting elements 5, 6, 7 when attracted and rotated by the magnetic field produced by a stator 3. Different type of magnetic force is separated by the leakage magnetism intercepting section 20 of the rotor magnet 17 from the magnetic forces generated by the rotor magnet 17 when it is rotated, and is not transmitted to the rotation detecting elements 5, 6, 7. Therefore, the rotation detecting elements 5, 6, 7 detect rotation without receiving leakage magnetism, and produce Hall voltage. This eliminates variation in Hall voltage produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor used as a driving source for a measuring instrument such as a timer by rotating at a periodic speed according to a sensor signal inside the motor.

[0002]

2. Description of the Related Art As a brushless motor as a driving source of a measuring instrument, there is known a brushless motor in which a rotor is arranged inside a stator and a rotor shaft provided in the rotor is connected to a measuring portion. With such a brushless motor,
One end of the stator coil provided in the stator is electrically connected to the drive current generating circuit, the other end of the stator coil is electrically connected to the rotation detecting element, and the rotation detecting element is electrically connected to the drive current generating circuit. It is connected. When an exciting current is supplied from the drive current generation circuit to the rotation detecting element, the rotation detecting element in the magnetic field of the stator coil generates a Hall voltage to excite the stator coil and rotate the stator. The rotor rotates due to the magnetic force.

[0003]

However, in the brushless motor described above, the magnet for generating the magnetic force for the rotation detecting element is provided separately from the magnet receiving the magnetic force of the stator on the extension line of the rotor shaft. However, there is a problem in that the rotor shaft becomes long, which may result in an increase in the overall size of the brushless motor. Some attempted to reduce the length of the rotor shaft by placing it near the magnet for receiving the magnetic field, but the Hall voltage generated by the rotation detection element due to the leakage magnetism from the magnet receiving the magnetic force of the stator. However, there is a problem in that the reliability is poor.

[0004]

SUMMARY OF THE INVENTION A brushless motor according to the present invention is
It is an object of the present invention to provide a brushless motor that is compact and has an external shape and that can improve reliability.

[0005]

Configuration of the Invention

[0006]

In a brushless motor according to claim 1 of the present invention, a motor case, a stator arranged inside the motor case and generating a magnetic field inside by energization, and a plurality of poles are attached. A rotor that is magnetized and has a rotor magnet that can be attracted by a magnetic field generated by the stator and that can generate a magnetic force with respect to the rotation detecting element, and that is rotatably disposed inside the stator in a motor case; The rotation detecting element, which is arranged close to the rotor magnet of the rotor and generates a voltage by the magnetic force generated by the rotor magnet, and the rotation detecting element which is arranged close to the rotation detecting element of the rotor magnet, are opposite to each other. It is characterized in that it is configured to include a leakage magnetic shield unit capable of separating magnetic force.

In a brushless motor according to a second aspect of the present invention, a motor case, a stator disposed inside the motor case and generating a magnetic field on the inner peripheral side when energized,
A rotor shaft rotatably attached to the motor case, a rotor base attached to the rotor shaft, and a first magnet formed in a cylindrical shape and attached to the outside of the rotor base and having a first pole magnetized. Part and second pole with second pole magnetized
The magnetic parts are sequentially arranged at a plurality of positions in the circumferential direction, and the magnetic field generated by the stator enables attraction.
A rotor magnet disposed inside the stator, a rotation detection element disposed on the side of the motor case close to the rotor magnet and generating a voltage by the magnetic force generated by the rotor magnet, the first magnetic portion and the second magnetic portion of the rotor magnet. It is characterized in that it is provided between the magnetic parts and is provided with a leakage magnetic blocking part capable of blocking the magnetism generated by the first magnetic part and the magnetic force generated by the second magnetic part.

In the brushless motor according to the third aspect of the present invention, the motor case, the end cover connected to one end of the motor case, and the tubular shape are arranged inside the motor case, and the inner case is formed by energization. A stator that generates a magnetic field on the circumferential side, a rotor bearing that is rotatably attached to the motor case and the end cover, a rotor shaft that is rotatably supported by the rotor bearing, a rotor base that is attached to the rotor shaft, and a cylinder. Has a magnet core attached to the outside of the rotor base, is arranged on the outer peripheral side of the magnet core integrally with the magnet core, and has a first magnetic portion magnetized with an N pole and an S pole. The magnetized second magnetic portions are sequentially arranged at a plurality of positions in the circumferential direction, and are attracted by the magnetic field generated by the stator, thereby A rotor magnet, a rotation detecting element that is disposed close to the end of the rotor magnet and that generates a voltage by the magnetic force generated by the rotor magnet, and an end of the first magnetic portion of the rotor magnet and a second end of the rotor magnet. A leakage magnetic blocking unit is provided between the ends of the magnetic unit in a groove shape and cut in the cylinder direction of the rotor magnet to block the magnetic force generated by the first magnetic unit and the magnetic force generated by the second magnetic unit. It is characterized by having the configuration.

[0009]

In the brushless motor according to claim 1 of the present invention, the rotor magnet included in the rotor is
When the stator is attracted by the magnetic field generated and rotates, a magnetic force is generated with respect to the rotation detecting element. Then, the contradictory magnetic forces of the magnetic force generated while the rotor magnet rotates are separated at the leakage magnetic shield of the rotor magnet and are not transmitted to the rotation detecting element, so that the rotation detecting element does not receive the leakage magnetism. Rotation is detected and Hall voltage is generated. Therefore, there is no variation in the Hall voltage generated by the rotation detecting element.

In the brushless motor according to the second aspect of the present invention, the rotor magnet of the rotor has a first magnetic portion when the first magnetic portion and the second magnetic portion are attracted and rotated by the magnetic field generated by the stator. From the second magnetic portion to the rotation detecting element, while generating a magnetic force from the second magnetic portion to the rotation detecting element. The opposing magnetic forces of the magnetic forces generated from the first magnetic portion and the second magnetic portion while the rotor magnet rotates are blocked by the leakage magnetic blocking portion of the rotor magnet and are not transmitted to the rotation detecting element. The rotation detecting element generates the Hall voltage without receiving the leakage magnetism of the first magnetic portion and the second magnetic portion. Therefore, there is no variation in the Hall voltage generated by the rotation detecting element.

In the brushless motor according to claim 3 of the present invention, the rotor magnet integrally provided on the magnet iron core outside the rotor base attached to the rotor shaft has the first magnetic portion and the magnetic field generated by the stator. When the second magnetic unit is attracted and rotates, the first magnetic unit generates a magnetic force with respect to the rotation detecting element, while the second magnetic unit generates the magnetic force.
A magnetic force is generated from the magnetic part to the rotation detecting element. The opposing magnetic forces of the magnetic forces generated from the first magnetic portion and the second magnetic portion while the rotor magnet is rotating are formed in a groove shape between the first magnetic portion and the second magnetic portion of the rotor magnet. Since it is not cut off at the leaked magnetic field cutoff portion and is not transmitted to the rotation detecting element, the rotation detecting element generates a Hall voltage without receiving the leakage magnetism of the first magnetic portion and the second magnetic portion. Therefore, there is no variation in the Hall voltage generated by the rotation detecting element.

[0012]

1 to 5 show one embodiment of a brushless motor according to the present invention.

The brushless motor 1 shown is mainly composed of a motor case 2, a stator 3, a rotor 4, a first hall element 5, a second hall element 6 serving as a rotation detecting element, and a third hall element 7. Has been done.

The motor case 2 is composed of a case body 2a and an end cover 2b which are formed in a substantially cylindrical shape. The stator 3 is attached to the inside of the case body 2a and the end of the case body 2a is opened at one end. Cover 2b
Are combined. A first rotor bearing 8 is attached to the center of the other end of the case body 2a.

A second rotor bearing 9 is attached to the center of the end cover 2b. The second rotor bearing 9 and the above-mentioned first rotor bearing 8 have a rotor 4 which will be described later.
The rotor shaft 12 provided in the above is inserted.

A disk-shaped circuit board 10 is attached to the end cover 2b, and an additional circuit 11 such as an amplifier is electrically connected and arranged on the surface of the circuit board 10. On the back surface of the circuit board 10, the first Hall element 5,
The second Hall element 6 and the third Hall element 7 are attached respectively. In the center of the circuit board 10, a rotor shaft insertion hole 10a for inserting a rotor shaft 12 described later is provided.

The first, second, and
As shown in FIG. 2, the third Hall elements 5, 6 and 7 are arranged on the concentric circles of the rotor shaft insertion hole 10a at equal angles and in a non-contact manner with a rotor magnet 17 described later.

In the first Hall element 5, one excitation current input terminal is electrically connected to one external connection terminal 30 described later, and the other excitation current input terminal is the other external connection described later. As shown in FIG. 4, the hall voltage output terminal is electrically connected to the connection terminal 31 and the hall voltage output terminal is provided on the front surface of the circuit board 10 through the logic circuit 21.
Is electrically connected to the base of the first transistor TR1 (NPN type) and the base of the fifth transistor TR5 (NPN type). The first Hall element 5 is
While being arranged in a magnetic field generated by a rotor magnet 17, which will be described later, by supplying an exciting current from one exciting current input terminal to the other exciting current input terminal, the Hall voltage (Hu) is applied to the Hall voltage output terminal. Therefore, the generated Hall voltage causes the logic circuit 21 to turn on the first transistor TR1 and the fifth transistor TR5 of the additional circuit 11, and the turning on of the first transistor TR1 and the fifth transistor TR5 causes a stator described later. The first coil portion 14a provided in the coil 14 and the second
The coil portion 14b, the fourth coil portion 14d, and the third coil portion 14c are excited.

In the second Hall element 6, one excitation current input terminal is electrically connected to one external connection terminal 30 described later, and the other excitation current input terminal is the other external connection described later. As shown in FIG. 4, the hall voltage output terminal is electrically connected to the connection terminal 31 and the hall voltage output terminal is provided on the front surface of the circuit board 10 through the logic circuit 21.
Is electrically connected to the base of the second transistor TR2 (NPN type) and the base of the sixth transistor TR6 (NPN type). The second Hall element 6 is
While being arranged in a magnetic field generated by a rotor magnet 17, which will be described later, by supplying an exciting current from one exciting current input terminal to the other exciting current input terminal, the hall voltage (Hv) is applied to the hall voltage output terminal. Therefore, the generated Hall voltage causes the logic circuit 21 to turn on the second transistor TR2 and the sixth transistor TR6 of the additional circuit 11, and the turning on of the second transistor TR2 and the sixth transistor TR6 causes a stator described later. Third coil portion 14c provided in the coil 14, fourth
The coil portion 14d, the sixth coil portion 14f, and the fifth coil portion 14e are excited.

In the third Hall element 7, one excitation current input terminal is electrically connected to one external connection terminal 30 described later, and the other excitation current input terminal is the other external connection described later. As shown in FIG. 4, the hall voltage output terminal is electrically connected to the connection terminal 31 and the hall voltage output terminal is provided on the front surface of the circuit board 10 through the logic circuit 21.
Are electrically connected to the base of the third transistor TR3 (NPN type) and the base of the fourth transistor TR4 (NPN type). The third Hall element 7 is
The hall voltage (Hw) is supplied to the hall voltage output terminal by supplying the exciting current from one exciting current input terminal to the other exciting current input terminal in a state where the magnet is placed in a magnetic field generated by a rotor magnet 17 described later. Therefore, the generated Hall voltage causes the logic circuit 21 to turn on the third transistor TR3 and the fourth transistor TR4 of the additional circuit 11, and the turning on of the third transistor TR3 and the fourth transistor TR4 causes a stator described later. The fifth coil portion 14e provided in the coil 14, the sixth
The coil portion 14f, the second coil portion 14b, and the first coil portion 14a are excited.

First, second and third Hall elements 5, 6, 7
Are arranged apart from each other in the equiangular range on the circuit board 10, so that the Hall voltage (Hu) generated by the first Hall element 5 is equal to the Hall voltage (Hv) generated by the second Hall element 6. ), The Hall voltage (Hv) generated by the second Hall element 6 has a phase difference of 1/3 cycle with respect to
Has a phase difference of 1/3 cycle with respect to the Hall voltage (Hw) generated by the third Hall element 7.

In the stator 3, as shown in FIG.
A core 13 having a coil winding portion 13a having a predetermined number of slots (6 slots) is provided, and
As shown in FIG. 4, only the coil winding portion 13 of the core 13 is shown.
The first coil portion 14a, the second coil portion 14b, the third coil portion 14c, the fourth coil portion 14d, the fifth coil portion 14e, and the sixth coil portion 14f that are wound for each a.
The stator coil 14 is provided. The rotor 4 is arranged inside the stator 3.

The stator coil 14 is electrically connected to the first Hall element 5, the second Hall element 6, and the third Hall element 7 through the additional circuit 11 shown in FIG. Are a first transistor TR1 (NPN type) and a fifth transistor TR5 (NPN type) which are turned on by a signal generated by the logic circuit 21 by a Hall voltage generated by the first Hall element 5, and a second Hall element. Logic circuit 2 according to the Hall voltage generated from 6
The second transistor TR2 (NPN type) and the sixth transistor TR6 which are turned on by the signal generated from 1
(NPN type), and a third transistor TR3 (NPN type) and a fourth transistor TR4 (NPN type) which are turned on by a signal generated by the logic circuit 21 by the Hall voltage generated by the third Hall element 7. ing.

The rotor 4 is provided with a rotor shaft 12, a rotor base 16 and a rotor magnet 17.

Since the rotor shaft 12 is inserted through the first rotor bearing 8 and the second rotor bearing 9 as described above, the first rotor bearing 8 and the second rotor bearing 9 are inserted.
It is rotatably supported by. A stopper 19 is attached to the rotor shaft 12 on the side of the second rotor bearing 9, and the stopper 19 can be slidably contacted with the second rotor bearing 9. Thrust movement is regulated. A rotor base 16 is attached to the outside of the rotor shaft 12.

The rotor base 16 is made of a non-magnetic material and is formed into a cylindrical shape. The rotor shaft 12 is press-fitted in the center of the rotor base 16 so that it can be slidably contacted with the first rotor bearing 8. Thrust movement of the shaft 12 in the direction of the first rotor bearing 8 is restricted. Rotor base 16
A rotor magnet 17 is arranged on the outer peripheral side of.

The rotor magnet 17 is provided with a magnet iron core 18 formed of a magnetic material in a cylindrical shape, and the first magnetic portion sequentially arranged in the circumferential direction on the outer peripheral side of the magnet iron core 18. 17a, second
The magnetic parts 17b are provided respectively. The length of the magnet core 18 in the axial direction of the rotor shaft 12 is the first magnetic portion 17
a, smaller than the second magnetic portion 17b. In this case, as shown in FIG. 2, the first magnetic portion 17a and the second magnetic portion 1
7b are staggered and arranged in two places.
The magnetic portion 17a is magnetized with the N pole, which is the first magnetic pole,
The magnetic portion 17b is magnetized with the S pole, which is the second magnetic pole.

Since the rotor magnet 17 has magnetic poles which are opposite to each other on the outer peripheral side, when a rotating magnetic field is generated for each slot on the inner peripheral side of the stator 3, the rotor magnet 17 repels or is attracted by the mutually opposing magnetic forces. Rotational energy is given by to rotate with the rotor shaft 12.

In the rotor magnet 17, the leakage magnetic shield 20 is arranged between the first magnetic portion 17a and the second magnetic portion 17b.

As shown in FIG. 3, the magnetic leakage leakage section 20 is provided on the second rotor bearing 9 side of the rotor base 16 at the end of the first magnetic portion 17a and the end of the second magnetic portion 17b, respectively. In between, the groove is formed in four places, and has a depth dimension L1 in the axial direction of the rotor shaft 12, as shown in FIG.

The magnetic leakage leakage section 20 is located on the side of the rotor magnet 17 facing the second rotor bearing 9 and has the first magnetic section 17a.
And the second magnetic portion 17b, the magnetic force generated by the first magnetic portion 17a and the magnetic force generated by the second magnetic portion 17b are separated to separate the first magnetic portion 17a and the second magnetic portion 17b. Second from the magnetic part 17b
The rotor bearing 9 side is blocked so as not to generate magnetic force to form a dead region where magnetic force does not act.

In the rotor magnet 17, the leakage magnetic shield portion 20 has an end portion of the first magnetic portion 17a and the second magnetic portion 17b.
Since it is formed at four places in a groove shape between the respective end portions of the rotor magnet, the dead area is also formed in the second portion of the rotor magnet 17.
The magnetic field is generated on the second rotor bearing 9 side in the portions that are arranged at four positions on the rotor bearing 9 side and in which the leakage magnetic shield 20 is not formed. That is, the rotor magnet 17
Is a magnetic leakage block 20 on the circumference of a circle having substantially the same radius as the circle formed by the first, second and third Hall elements 5, 6, 7.
The first magnetic portion 17a, the leakage magnetic shield portion 20, the second magnetic portion 17b, the leakage magnetic shield portion 20, the first magnetic portion 17a,
The magnetic leakage block 20 and the second magnetic portion 17b are arranged in non-contact with the first, second, and third Hall elements 5, 6, and 7, respectively.

The brushless motor having such a structure is attached to a measuring instrument (not shown), and the external connection terminals 30 and 31 are electrically connected to the current supply circuit. Then, when a drive current is supplied from one external connection terminal 30 to the other external connection terminal 31 and the first Hall element 5 is in the magnetic field of the rotor magnet 17, this first
Hall voltage is generated from the Hall element 5 of FIG. 1, the first transistor TR1 and the fifth transistor TR5 of the additional circuit 11 are turned on by the signal generated from the logic circuit 21 by the generated Hall voltage, and the first of the stator coil 14 2nd, 4th, 3rd coil parts 14a, 14b, 14
By generating a rotating magnetic field on the inner peripheral sides of d and 14c, the first magnetic portion 17a and the second magnetic portion 17b included in the rotor magnet 17 impart rotational energy to the rotor 4 by the rotating magnetic field from the stator coil 14. For,
The rotor shaft 12 starts rotating.

When the rotor shaft 12 starts to rotate, the second Hall element 6 is placed in the magnetic field of the rotor magnet 17, and a Hall voltage is generated from this second Hall element 6, and the generated Hall voltage causes a logic. The signal generated from the circuit 21 turns on the second transistor TR2 and the sixth transistor TR6 of the additional circuit 11, and the third, fourth, sixth, and fifth coil portions 14c, 14d, and 14f of the stator coil 14 are By generating a rotating magnetic field on the inner peripheral side of 14e, the first magnetic portion 17a and the second magnetic portion 17b included in the rotor magnet 17 impart rotational energy to the rotor 4 by the rotating magnetic field from the stator coil 14 and rotate the rotor. As the shaft 12 continues to rotate and the rotor shaft 12 rotates, the rotor magnet 1
The third Hall element 7 is placed in the magnetic field of
Hall voltage is generated from the Hall element 7 of the above, the generated Hall voltage causes a signal generated from the logic circuit 21 to turn on the third transistor TR3 and the fourth transistor TR4 of the additional circuit 11, and the fifth of the stator coil 14 6th, 2nd, 1st coil parts 14e, 14f, 14
By generating a rotating magnetic field on the inner peripheral sides of b and 14a, the first magnetic portion 17a and the second magnetic portion 17b provided in the rotor magnet 17 apply rotational energy to the rotor 4 by the rotating magnetic field from the stator coil 14. The rotor shaft 12 continues to rotate, and by repeating this, the rotor shaft 12 rotates.

While the rotor shaft 12 is rotating, the rotor magnet 17 approaches the rotor magnet 17 in a non-contact manner, and the first, second, and third Hall elements 5, which are arranged in the magnetic field generated by the stator 3,
As shown in FIG. 4, the first and second Hall elements 6 and 7 are supplied with an exciting current from one exciting current input terminal 30 to the other exciting current input terminal 31. Hall voltage with a phase difference of 5, 6, and 7 (H
u) (Hv) (Hw) occurs. Then, based on the Hall voltages (Hu) (Hv) (Hw) generated from the first, second, and third Hall elements 5, 6, and 7, the logic circuit 21
As a result, as shown in FIG. 5, the signals are converted into a U-phase signal in the first Hall element 5, a V-phase signal in the second Hall element 6, and a third Hall element W-phase signal.

At this time, as the rotor magnet 17 rotates, the first, second, and third Hall elements 5, which are arranged close to the rotor magnet 17 in a non-contact manner,
Reference numerals 6 and 7 denote the leakage magnetic shields 20 of the rotor magnet 17.
The magnetic force generated by the first magnetic portion 17a and the magnetic force generated by the second magnetic portion 17b are separated from each other, and the magnetic force is not received in the dead region formed by the leakage magnetic blocking portion 20, so that the magnetic force generated from the first magnetic portion 17a is generated. The Hall voltage is generated without receiving the leakage magnetism generated and the leakage magnetism generated from the second magnetic portion 17b. Further, it is not necessary to attach a magnet for generating a magnetic force to the rotation detecting element on the extension line of the rotor shaft separately from the magnet that receives the magnetic force of the stator. Since the rotor shaft 17 is arranged close to the rotor magnet 17, the rotor shaft 12 having a small length dimension is used.

[0037]

As described above, according to the brushless motor of the first aspect of the present invention, the rotor magnet included in the rotor is detected by the rotation detecting element when the rotor magnet is attracted by the magnetic field generated by the stator and rotates. Generates a magnetic force against. Then, the contradictory magnetic forces of the magnetic force generated while the rotor magnet rotates are separated at the leakage magnetic shield of the rotor magnet and are not transmitted to the rotation detecting element, so that the rotation detecting element does not receive the leakage magnetism. Since the Hall voltage is generated by detecting the rotation, there is no variation in the Hall voltage generated by the rotation detection element,
As a result, the length dimension is reduced, and the excellent effect of improving reliability can be achieved.

According to the brushless motor of the second aspect of the present invention, in the rotor magnet included in the rotor, when the first magnetic portion and the second magnetic portion are attracted by the magnetic field generated by the stator and are rotated, A magnetic force is generated from the magnetic portion to the rotation detecting element, while a magnetic force is generated from the second magnetic portion to the rotation detecting element. The opposing magnetic forces of the magnetic forces generated from the first magnetic portion and the second magnetic portion while the rotor magnet rotates are blocked by the leakage magnetic blocking portion of the rotor magnet and are not transmitted to the rotation detecting element. Since the rotation detecting element generates the Hall voltage without being affected by the leakage magnetism of the first magnetic unit and the second magnetic unit, the Hall voltage generated by the rotation detecting element does not vary, thereby reducing the length dimension. At the same time, it has an excellent effect of improving reliability.

According to the brushless motor of the third aspect of the present invention, the rotor magnet integrally provided on the magnet iron core outside the rotor base attached to the rotor shaft has the first magnetic field generated by the magnetic field generated by the stator. When the first portion and the second magnetic portion are attracted and rotate, the first magnetic portion generates a magnetic force with respect to the rotation detecting element, while the second magnetic portion
A magnetic force is generated from the magnetic part to the rotation detecting element. The opposing magnetic forces of the magnetic forces generated from the first magnetic portion and the second magnetic portion while the rotor magnet is rotating are formed in a groove shape between the first magnetic portion and the second magnetic portion of the rotor magnet. Since it is not transmitted to the rotation detecting element by being blocked by the leakage magnetic blocking section, the rotation detecting element generates a Hall voltage without receiving the leakage magnetism of the first magnetic section and the second magnetic section. There is an excellent effect that the Hall voltage generated by the element does not vary, thereby reducing the length dimension and improving the reliability.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of an embodiment of a brushless motor according to the present invention.

FIG. 2 is a schematic diagram of the brushless motor shown in FIG.
-A) It is a line sectional view.

3 is an external perspective explanatory diagram of a rotor in the brushless motor shown in FIG. 1. FIG.

FIG. 4 is a circuit diagram of an additional circuit used in the brushless motor shown in FIG.

5 is an explanatory diagram of a Hall voltage generated by a rotation detecting element in the brushless motor shown in FIG.

[Explanation of symbols]

 1 Brushless Motor 2 Motor Case 2b End Cover 3 Stator 4 Rotor 5 Rotation Detection Element 6 Rotation Detection Element 7 Rotation Detection Element 8 (Rotor Bearing) First Rotor Bearing 9 (Rotor Bearing) Second Rotor Bearing 12 Rotor Axis 16 Rotor base 17 Rotor magnet 17a First magnetic part 17b Second magnetic part 18 Magnet iron core 20 Leakage magnetic shield part

Claims (3)

[Claims] 1. A motor case, a stator arranged inside the motor case, which generates a magnetic field inside when energized, and a plurality of poles are magnetized so that the magnetic field generated by the stator can attract the magnetic field. And a rotor magnet capable of generating a magnetic force with respect to the rotation detecting element, the rotor being rotatably arranged in the motor case and arranged inside the stator, and arranged close to the rotor magnet of the rotor, A rotation detecting element that generates a voltage due to the magnetic force generated by the rotor magnet and a leakage magnetic shield that is disposed in a position close to the rotation detecting element of the rotor magnet and that can separate the opposing magnetic forces generated by the rotor magnet. A brushless motor characterized by having a section. 2. A motor case, a stator arranged inside the motor case and generating a magnetic field on the inner peripheral side when energized, a rotor shaft rotatably mounted on the motor case, and a rotor shaft mounted on the rotor shaft. A rotor base, and a first magnetic portion having a first pole magnetized and a second magnetic portion having a first pole magnetized and attached to the outside of the rotor base. The rotor magnets are sequentially arranged at a plurality of positions in the circumferential direction and are attracted by the magnetic field generated by the stator, and are arranged on the inner side of the stator and on the motor case side close to the rotor magnet. Disposed between the rotation detecting element that generates a voltage by the magnetic force generated by the rotor magnet and the first magnetic portion and the second magnetic portion of the rotor magnet. A brushless motor comprising: a leakage magnetic blocking unit capable of blocking the magnetism generated by the first magnetic unit and the magnetic force generated by the second magnetic unit. 3. A motor case, an end cover coupled to one end of the motor case, and a stator formed in a tubular shape and disposed inside the motor case, and generating a magnetic field on the inner peripheral side when energized. A rotor bearing rotatably mounted on the motor case and the end cover, a rotor shaft rotatably supported on the rotor bearing, a rotor base mounted on the rotor shaft, and formed in a cylindrical shape. A first magnetic part having a magnet core attached to the outside of the rotor base, arranged on the outer peripheral side of the magnet core integrally with the magnet core, and having an N pole magnetized and an S pole. The magnetized second magnetic portions are sequentially arranged at a plurality of positions in the circumferential direction, and
A rotor magnet that is attracted by the magnetic field generated by the stator and that is disposed inside the stator, and a rotor magnet that is disposed close to the end of the rotor magnet, and that generates a voltage by the magnetic force generated by the rotor magnet. A groove was formed between the detection element and the end of the first magnetic portion and the end of the second magnetic portion of the rotor magnet, and the groove was cut in the cylindrical direction of the rotor magnet to generate the first magnetic portion. A brushless motor comprising a leakage magnetic blocking unit capable of blocking the magnetic force and the magnetic force generated by the second magnetic unit.