JP2013090501A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor which contributes to the downsizing of an entire motor.SOLUTION: A circuit board 31 is provided in an axial space between a case body part 2 which houses a rotor 21 and is made of a magnetic body and an end frame 3 which covers an opening of the case body part 2, is made of a nonmagnetic material, and serves as a heat sink. A magnetic sensor 32a is provided between a rotor core 23 and the end frame 3 made of the nonmagnetic material.

Description

  The present invention relates to a motor.

  Conventionally, for example, as disclosed in Patent Document 1, a motor including a control circuit that controls rotation of a motor (rotor) is known. Such a motor is provided with a magnetic sensor for detecting the rotational position of the rotor, and the rotation of the rotor is controlled by a control circuit based on the rotational position information of the rotor from the magnetic sensor.

JP 2002-345211 A

  By the way, in the motor of the above-mentioned patent document 1, the stator and the rotor are accommodated in a cylindrical case, the opening of the case on the opposite side of the rotating shaft is covered with a heat sink, and further on the opposite side of the rotating shaft than the heat sink. A circuit board provided with a control circuit and the like is arranged. And the accommodation cover which accommodates a circuit board is attached to the heat sink. For this reason, the motor as a whole has been increased in size in the axial direction due to the influence of the cover and the like.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a motor that can contribute to downsizing of the entire motor.

  In order to solve the above-described problem, the invention described in claim 1 is a stator, and a plurality of permanent magnets which are arranged opposite to the stator and are long in the axial direction on a cylindrical rotor core at predetermined intervals in the circumferential direction. And a rotor having a pseudo magnetic pole formed between the permanent magnets and a magnet magnetic pole formed by the permanent magnets alternately arranged in the circumferential direction. A cylindrical magnetic case for housing the stator and the rotor, a nonmagnetic heat sink covering the opening of the magnetic case, a circuit board provided between the magnetic case and the nonmagnetic heat sink, and the rotor core And a magnetic sensor provided between the nonmagnetic heat sinks.

  In the present invention, a circuit board provided between the magnetic case for housing the stator and the rotor and a nonmagnetic heat sink covering the opening of the magnetic case and a magnetic sensor provided between the rotor core and the nonmagnetic heat sink are provided. As described above, since the circuit board is provided between the magnetic case and the nonmagnetic heat sink, the axial length of the entire motor as compared with the case where the circuit board is provided on the opposite side of the magnetic case in the axial direction with the heat sink as the center. This can be suppressed. In addition, since a magnetic case is used and the heat sink is made of a non-magnetic material, even if the rotor constitutes a pseudo magnetic pole, leakage flux from the rotor is induced to flow out to the anti-heat sink side. Outflow to the magnetic sensor side is suppressed. As a result, even if the heat sink is brought close to the magnetic sensor, adverse effects on the sensor can be suppressed, and further, the axial length of the entire motor can be suppressed. As a result, the overall motor can be reduced in size.

  A second aspect of the present invention is the motor according to the first aspect, wherein a rotating shaft to which the rotor core is fixed and rotated integrally with the rotor core is made of a nonmagnetic material. .

  In this invention, since the rotating shaft rotated integrally with the rotor core is made of a non-magnetic material, the leakage magnetic flux can be prevented from flowing into the rotating shaft, and adverse effects on the magnetic sensor can be suppressed.

  According to a third aspect of the present invention, in the motor according to the first aspect, the rotary shaft to which the rotor core is fixed and is rotated together with the rotor core is composed of a non-magnetic material only on the output side and a magnetic material on the non-output side. The gist of the invention is that the nonmagnetic heat sink, the circuit board, and the magnetic sensor are provided on the output side of the rotating shaft with respect to the rotor core.

  In the present invention, the rotating shaft is constituted by a non-magnetic material only on the output side and a magnetic material on the counter-output side, and the non-magnetic heat sink, the circuit board and the magnetic sensor are provided on the output side of the rotating shaft with respect to the rotor core. By setting it as such a structure, the influence of the leakage magnetic flux which flows into the non-output side of a rotating shaft with respect to the magnetic sensor provided in the output side of a rotating shaft rather than a rotor core can be suppressed further.

  According to a fourth aspect of the present invention, in the motor according to any one of the first to third aspects, the heating element provided on the circuit board is brought into contact with the nonmagnetic heat sink via a heat dissipation elastic body. This is the gist.

  In this invention, since the heating element provided on the circuit board is brought into contact with the nonmagnetic heat sink via the heat dissipation elastic body, the heat released from the heating element of the circuit board can be actively dissipated from the heat sink. it can. Moreover, since the elastic body is interposed between the heat sink and the heating element of the circuit board, damage to the heating element and the circuit board can be suppressed. In addition, the heating element comes into contact with the non-magnetic heat sink through the heat dissipation elastic body, but the heat dissipation elastic body can be made thin and a gap for avoiding contact with the heat sink (avoidance of damage, short circuit, etc.) Even if compared with the case where the is provided, the size can be reduced in the axial direction.

  The gist of a fifth aspect of the present invention is the motor according to any one of the first to fourth aspects, wherein the nonmagnetic heat sink has a contact surface that contacts the driven body housing.

In this invention, since the nonmagnetic heat sink has a contact surface that contacts the driven body housing, the heat from the heat sink can be further dissipated on the driven body side.
According to a sixth aspect of the present invention, in the motor according to any one of the first to fifth aspects, the stator winding is wound around the teeth by SC winding or concentrated winding. The gist.

  In the present invention, the winding of the stator is wound by SC winding or concentrated winding on the teeth, so that the axial length of the entire motor can be suppressed by suppressing the axial length of the stator. .

  According to a seventh aspect of the present invention, in the motor according to the sixth aspect, the winding of the stator is wound with SC winding around the teeth, and is driven with respect to one circuit board. The gist is that a circuit and a control circuit are provided.

  In the present invention, the axial length is suppressed by the SC winding to increase the radial length, and the radial length of the circuit board is increased accordingly, and the drive circuit and the control circuit are provided on one circuit board. By providing, it becomes unnecessary to provide a plurality of circuit boards in the axial direction, so that the axial length of the entire motor can be suppressed.

  Therefore, according to the above described invention, it is possible to provide a motor that can contribute to miniaturization of the entire motor.

It is sectional drawing of the motor in embodiment. It is a top view of the rotor and stator in an embodiment. It is a top view of the rotor and stator in another example.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, the motor M of this embodiment is an inner rotor type brushless motor. A motor case of the motor M includes a bottomed cylindrical case body 2 and a bottomed cylindrical end frame 3 assembled to the case body 2.

  The case body 2 is made of an iron-based magnetic material, and has a cylindrical tubular portion 2a and a bottom 2b that substantially closes the axially proximal end of the tubular portion 2a. It has a cylindrical shape. The opening 2c on the distal end side of the case main body 2 is closed by contacting the opening of the end frame 3 with a substantially bottomed cylindrical shape.

The bottom portion 2b is formed with a bearing housing portion 2d that is recessed toward the base end side in the central portion in the radial direction. An annular bearing 4 is accommodated in the bearing accommodating portion 2d.
The end frame 3 is a heat sink, and a bearing housing portion 3a that is recessed toward the distal end side is formed in the central portion in the radial direction. The bearing housing 3a is formed with a through hole 3b penetrating in the axial direction at the center of the bottom. An annular bearing 5 is accommodated in the bearing accommodating portion 3a. And each bearing 4 and 5 supports the rotating shaft 22 of the rotor 21 mentioned later so that rotation is possible. Further, the bottomed cylindrical end frame 3 is configured such that a bottom outer surface 3d thereof abuts a driven body housing (not shown).

  Inside the motor case, a cylindrical stator 11 is fixed to the inner peripheral surface of the cylindrical portion 2a. As shown in FIG. 1, the stator 11 includes a substantially cylindrical stator core 12 formed by laminating a plurality of magnetic metal plate materials. As shown in FIG. 2, the stator core 12 includes a cylindrical inner fitting portion 12 a and teeth 12 b extending radially inward from the inner peripheral surface of the inner fitting portion 12 a. Twelve teeth 12b are formed at equal angular intervals in the circumferential direction of the stator core 12, slots are formed between the teeth 12b, and the windings 13 are concentrated on the teeth 12b so as to be accommodated in the slots between the teeth 12b. Is wound. A rotor 21 is arranged inside the stator 11 in the radial direction.

  The rotor 21 includes a cylindrical rotor core 23 that is arranged to face the stator 11 in the radial direction and is fixed to the rotary shaft 22, and a plurality of N-pole magnets 24 in the circumferential direction of the outer peripheral portion of the rotor core 23.

  The rotating shaft 22 includes a core fixing portion 22a on the side opposite to the output (base end) that fixes the rotor core 23, and an output portion 22b that is connected to the output side of the core fixing portion and to which the output joint 6 is attached. The core fixing portion 22a is made of an iron-based magnetic material, and the output portion 22b is made of a non-magnetic material such as SUS.

  As shown in FIG. 1, the output portion 22b of the rotating shaft 22 is supported by the bearing 5 in the bearing housing portion 3a on the output (tip) side, and protrudes from the through hole 3b to the outside of the end frame 3. ing. An output joint 6 for connecting to an external mechanism such as a speed reducer is fixed to the protruding tip end portion (output side end portion) of the rotating shaft 22. Further, the core fixing portion 22a of the rotating shaft 22 is pivotally supported by the bearing 4 accommodated in the bearing accommodating portion 2d on the opposite output (base end) side.

  On the outer periphery of the rotor core 23, integrally formed salient poles 23 a are arranged with gaps between the magnets 24. That is, the magnets 24 and the salient poles 23a are alternately arranged at equal angular intervals, and the rotor 21 is a so-called continuous pole type of 14 poles that causes the salient poles 23a to function as the S poles with respect to the N pole magnet 24. It is configured. Since the number of pole pairs is an odd number from the 14 magnetic poles, the magnet 24 and the salient pole 23a are at positions opposite to each other in the circumferential direction by 180 °.

  Here, as shown in FIG. 1, a circuit board 31 is fixed to the opening 3 c of the end frame 3. The circuit board 31 has a disk shape, and a magnetic sensor 32a is provided on the surface on one side (the case body 2 side). The magnetic sensor 32 a is provided so as to face the sensor magnet 32 b fixed to the output portion 22 b of the rotating shaft 22 in the radial direction. The magnetic sensor 32a is, for example, an MR sensor (magnetoresistive element).

  As shown in FIG. 1, a detection circuit (connected to a magnetic sensor 32a, which is formed by a plurality of circuit elements and circuit patterns including a field effect transistor (hereinafter referred to as FET) 33 on a circuit board 31. (Not shown), a control circuit (not shown) that controls the supply of current to the winding 13 of the stator 11, and a drive circuit (not shown) that supplies current to the winding 13 based on a command from the control circuit. Is provided. The circuit board 31 is configured in such a manner that a lead wire 13 a drawn from the winding 13 is electrically connected to a drive circuit on the circuit board 31.

The FET 33 provided on the circuit board 31 is in contact with a bottomed cylindrical end frame 3 as a heat sink via an elastic member 34 having a heat dissipation property.
In the motor M configured as described above, the magnetic sensor 32a shown in FIG. 1 detects a change in the magnetic field of the sensor magnet 32b accompanying the rotation of the rotary shaft 22, and a rotation detection signal corresponding to the detection result is sent to the detection circuit described above. Output. The detection circuit detects the rotational position of the rotor 21 based on the rotation detection signal and outputs it to the control circuit. Then, the control circuit determines an appropriate drive current from time to time based on the detected rotational position and the like, and outputs the information to the drive circuit. The drive circuit generates a drive current based on information from the control circuit, supplies the drive current to the winding 13 of the stator 11 via the lead wire 13a, and rotates the rotor 21.

Next, the operation of this embodiment will be described.
As shown in FIG. 1, a circuit board 31 is provided between the case main body 2 made of a magnetic material that accommodates the rotor 21 and the end frame 3 as a heat sink made of a nonmagnetic material that covers the opening of the case main body 2. Is provided. A magnetic sensor 32 a is provided between the rotor 21 and the end frame 3. At this time, even if the magnetic sensor 32a and the end frame 3 made of a non-magnetic material are arranged close to each other, the end frame 3 is made of a non-magnetic material, so that the magnetic sensor 32a can be prevented from being influenced other than the sensor magnet 32b. Can be done.

  Further, in the rotating shaft 22, only the output portion 22b on the output side is made of a non-magnetic material, and the core fixing portion 22a on the opposite output side is made of a magnetic material, so that leakage flux flows into the core fixing portion 22a on the opposite output side. Thus, the leakage magnetic flux does not flow into the nonmagnetic output portion 22b.

Next, characteristic effects of the present embodiment will be described.
(1) A circuit board 31 is provided between the case main body 2 made of a magnetic material that accommodates the rotor 21 and the end frame 3 as a heat sink made of a non-magnetic material that covers the opening of the case main body 2. . As described above, since the circuit board 31 is provided between the case body 2 and the end frame 3, as compared with the case where the circuit board 31 is provided on the opposite side in the axial direction of the case body 2 around the end frame 3. The axial length of the motor M as a whole can be suppressed. Further, since the case body 2 as a magnetic case is used and the end frame 3 as a heat sink is made of a nonmagnetic material, even if the rotor 21 constitutes a pseudo magnetic pole, leakage from the rotor 21 The magnetic flux is guided to flow out to the end frame 3 side and is prevented from flowing out to the magnetic sensor 32a side. As a result, a magnetic sensor 32a is provided between the rotor core 23 and the end frame 3, and even if the end frame 3 approaches the magnetic sensor 32a, adverse effects on the magnetic sensor 32a sensor can be suppressed. The direction length can be suppressed. As a result, the size of the entire motor M can be reduced.

  (2) The rotating shaft 22 is configured such that only the output portion 22b on the output side is made of a non-magnetic material, and the core fixing portion 22a on the opposite output side is made of a magnetic material. The substrate 31 and the magnetic sensor are provided on the output side of the rotating shaft 22 with respect to the rotor core 23. By adopting such a configuration, it is possible to further suppress the influence of the leakage magnetic flux flowing into the core fixing portion 22a on the opposite output side of the rotary shaft 22 to the magnetic sensor 32a provided on the output side of the rotary shaft 22 relative to the rotor core 23. Can do.

  (3) Since the FET 33 serving as a heating element provided on the circuit board 31 is brought into contact with the end frame 3 serving as a heat sink via an elastic member 34 having a heat dissipation property, heat released from the FET 33 on the circuit board 31 Can be actively radiated from the end frame 3 as a heat sink. In addition, since an elastic body is interposed between the end frame 3 and the FET 33 of the circuit board 31, damage to the FET 33 and damage to the circuit board 31 can be suppressed. In addition, the heating element comes into contact with the non-magnetic heat sink through the heat dissipation elastic body, but the heat dissipation elastic body can be made thin and a gap for avoiding contact with the heat sink (avoidance of damage, short circuit, etc.) Even if compared with the case where the is provided, the size can be reduced in the axial direction.

  (4) Since the end frame 3 as a heat sink has a bottom outer surface 3d as an abutting surface that comes into contact with the driven body housing, heat from the end frame 3 can be further dissipated on the driven body side. The bottom outer surface 3d is preferably formed so as to include a surface facing the circuit element that is in contact with the end frame 3 via the elastic member 34 in the axial direction.

  (5) Since the windings 13 of the stator 11 are wound in a concentrated manner around the teeth 12b, the axial length of the motor M as a whole can be suppressed by suppressing the axial length of the stator 11. Become.

In addition, you may change embodiment of this invention as follows.
In the above embodiment, the core fixing portion 22a of the rotating shaft 22 is made of a magnetic material, and the output portion 22b of the rotating shaft 22 is made of a nonmagnetic material. However, the rotating shaft 22 may be made of only a nonmagnetic material. . By adopting such a configuration, the number of parts can be suppressed, leakage flux can be prevented from flowing into the rotating shaft 22, and adverse effects on the magnetic sensor 32a can be suppressed.

  In the above embodiment, the windings 13 are concentrated windings, but are not limited thereto. For example, as shown in FIG. 3, a U-shaped segment SG made of an elongated conductor plate is inserted into each slot from the proximal end side in the axial direction toward the distal end side from the two distal end sides of the U-shape. The winding 13 may be configured by a so-called SC winding in which two U-shaped tips of the segments SG are joined according to a predetermined rule. Thus, by making the winding 13 the SC winding, the axial length can be suppressed while increasing the winding occupation ratio of the slot, while the radial length is increased. By utilizing this, the length of the circuit board 31 in the radial direction is expanded and the circuit board 31 is provided with a drive circuit and a control circuit, so that it is not necessary to provide a plurality of circuit boards 31 in the axial direction. It becomes possible to suppress the axial length of M as a whole. Further, the cost of the motor M can be reduced by reducing the number of parts.

  In the above embodiment, only the FET 33 as the heating element is configured to contact the end frame 3 as the heat sink via the elastic member 34, but the heating element other than the FET 33 is used as the end as the heat sink via the elastic member 34. You may employ | adopt the structure contact | abutted with the flame | frame 3. FIG. Moreover, you may employ | adopt the structure which contact | abuts heat generating bodies, such as FET33, directly to the end frame 3 as a heat sink, without going through the elastic member 34. FIG.

In the above embodiment, the end frame 3 as a heat sink is configured to abut against the non-driving body housing, but a configuration that does not abut may be employed.
In the above embodiment, the single circuit board 31 is configured. However, a configuration may be adopted in which a plurality of circuit boards are provided and each circuit is provided individually.

  DESCRIPTION OF SYMBOLS 2 ... Case main-body part as a magnetic case, 3 ... End frame as a nonmagnetic heat sink, 11 ... Stator, 12b ... Teeth, 13 ... Winding, 21 ... Rotor, 22 ... Rotating shaft, 23 ... Rotor core, 31 ... Circuit board 32a, a magnetic sensor, 34, an elastic member as a heat dissipation elastic body, M, a motor.

Claims (7)

A stator configured with windings on the teeth;
A pseudo magnetic pole formed between the permanent magnet and the permanent magnet, wherein a plurality of axially long permanent magnets are arranged at predetermined intervals in the circumferential direction on a cylindrical rotor core that is disposed opposite the stator. A motor comprising a rotor formed by alternately arranging magnet magnetic poles formed of the permanent magnets in the circumferential direction,
A cylindrical magnetic case for housing the stator and the rotor;
A nonmagnetic heat sink covering the opening of the magnetic case;
A circuit board provided between the magnetic case and the non-magnetic heat sink in the axial direction;
A motor comprising: a magnetic sensor provided between the rotor core and the nonmagnetic heat sink to detect a rotational position of the rotor. The motor according to claim 1,
A rotating shaft on which the rotor core is fixed and rotated integrally with the rotor core is made of a non-magnetic material. The motor according to claim 1,
The rotary shaft to which the rotor core is fixed and rotated integrally with the rotor core is configured such that only the output side is made of a non-magnetic material and the counter-output side is made of a magnetic material.
The non-magnetic heat sink, the circuit board, and the magnetic sensor are provided on the output side of the rotating shaft with respect to the rotor core. The motor according to any one of claims 1 to 3,
The heating element provided on the circuit board is in contact with the nonmagnetic heat sink via a heat radiating elastic body. In the motor according to any one of claims 1 to 4,
The non-magnetic heat sink has a contact surface that contacts a driven body housing. In the motor according to any one of claims 1 to 5,
The motor is characterized in that the winding of the stator is wound around the teeth by SC winding or concentrated winding. The motor according to claim 6, wherein
The stator winding is wound around the teeth with SC winding,
A motor comprising a drive circuit and a control circuit for one circuit board.

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