JP6027463B2 - Rotor with temperature measurement function - Google Patents

Description

  The present specification discloses a technique relating to a rotor that is housed in a space surrounded by a stator coil of a motor and that rotates by a rotating magnetic field generated by controlling energization of the stator coil.

  Patent Document 1 discloses a rotor having a temperature measurement function. The rotor includes a rotor core and a permanent magnet fixed to the rotor core. The rotor core is rotatably supported with respect to the stator coil, and has a substantially cylindrical shape. A plurality of permanent magnets are used, and the plurality of permanent magnets are fixed to the rotor core. A rotating magnetic field is generated by controlling energization of the stator coil, and the rotor rotates by the rotating magnetic field.

  When the rotor is rotated by energizing the stator coil, the rotor generates heat and the rotor temperature rises. Since the permanent magnet reaches demagnetization or demagnetization when the temperature rises above a predetermined temperature, and the motor torque decreases, it is necessary to measure the rotor temperature.

  In the technique of Patent Document 1, an RFID tag with a temperature sensor is provided on the rotor. The RFID tag with a temperature sensor here is a power generation coil, a power supply circuit that converts power generated by the power generation coil into drive power, a temperature sensor circuit that is driven by power from the power supply circuit, and power that is driven from the power supply circuit. In addition, it is equipped with a transmitter circuit that wirelessly transmits the measured value by the temperature sensor circuit. When the power generation coil is fixed to the rotor, the magnetic flux intensity passing through the power generation coil changes as the rotor rotates in the space surrounded by the stator coil, and the power generation coil generates power by changing the magnetic flux intensity. To do.

  According to the above technique, if a power line for supplying power for temperature measurement from the outside of the rotor is not required, a signal line for transmitting the measurement value to the outside of the rotor is not required. The rotor temperature can be measured without connecting to the rotating rotor.

JP 2009-247084 A

With the technique of Patent Document 1, it is possible in principle to measure the rotor temperature without connecting to the rotating rotor, but it is difficult to realize (practicalize) the technique.
The rotor rotates following the rotating magnetic field generated by the stator coil. That is, the relationship between the magnetic field and the rotor is basically constant. Therefore, the strength of the magnetic flux passing through the power generation coil is basically constant. Actually, the magnetic flux intensity passing through the power generation coil changes depending on the rotation angle with respect to the stator coil, but the amount of change is small, and in order to generate power using a small change in magnetic flux intensity, the power generation coil for the rotor The mounting posture is important. Further, if the transmission circuit is not disposed at a position opened outside the rotor, the radio wave does not reach the outside of the rotor and cannot be received outside the rotor. Furthermore, the rotor rotates at a high speed and a strong centrifugal force acts. It is difficult to mount each of the power generation coil, the temperature sensor circuit, and the transmission circuit on the rotor on which a strong centrifugal force acts so that each of them exhibits its function. In response to these problems, the technology of Patent Document 1 merely illustrates the installation position of the RFID tag with a temperature sensor, and does not disclose the mounting structure of the power generation coil.

In the present specification, a technique for mounting a member necessary for measuring a rotor temperature and transmitting a measured value by radio waves in addition to a power generation coil is disclosed.
The rotor disclosed in this specification includes a rotor core and a plurality of permanent magnets. The rotor core is used in a state of being rotatably supported with respect to the stator coil, and has a substantially cylindrical shape. A plurality of permanent magnets are fixed to the rotor core. The rotor core is formed with a hole that extends inward of the rotor core in parallel with the rotation axis of the rotor core and opens at an end surface in the rotation axis direction of the rotor core. A power generation coil extending along the hole and an electronic component connected to the power generation coil are accommodated in the hole. The electronic component includes a power supply circuit that converts power supplied from the power generation coil into drive power, a temperature sensor circuit that is driven by power from the power supply circuit, and measurement of the temperature sensor circuit that is driven by power from the power supply circuit. Equipped with a transmitter circuit that transmits values wirelessly.

  According to the above, the outer sides of the power generation coil and the electronic component are covered with the rotor core, and even if a strong centrifugal force acts on the power generation coil, the power generation coil or the like is not scattered. Furthermore, the transmission circuit is accommodated in a hole communicating with the outside of the rotor, and radio waves transmitted from the transmission circuit reach the outside of the rotor through the hole. Measurement values can be received outside the rotor.

In some cases, the permanent magnet is fixed inside the rotor core, and a flux barrier that extends in parallel with the rotation axis of the rotor core and opens at the end surface in the rotation axis direction of the rotor core may be formed. In that case, the flux barrier can be used for a hole for accommodating the power generation coil and the electronic component.
The flux barrier is an air gap that prohibits the passage of magnetic flux and improves the rotational efficiency of the motor, and is formed in the existing rotor core. Since the air gap is used to accommodate the members necessary for temperature measurement, it is not necessary to change the design of the existing rotor core. When the power generation coil is accommodated in the air gap through which the magnetic flux does not pass, since the magnetic flux does not pass through the power generation coil, the power generation coil should not generate power. However, in reality, there is a magnetic flux that leaks into the air gap, and the strength of the leakage magnetic flux changes following the rotation of the rotor, and an electromotive force is generated in the power generation coil due to the change in the strength of the leakage magnetic flux. The strength of the magnetic flux leaking into the air gap is low and does not affect the motor characteristics. However, the electric power required for the temperature sensor circuit and the transmission circuit is very weak, and sufficient electric power can be generated to drive the temperature sensor circuit and the transmission circuit. When a member necessary for temperature measurement is accommodated in the flux barrier, it is not necessary to change the existing rotor core, and a temperature measurement function can be added without affecting the performance of the existing motor.

  The flux barrier may extend along the permanent magnet. In this case, it is preferable to arrange the electronic component for temperature measurement in contact with the permanent magnet. The temperature of the permanent magnet can be directly measured.

The disassembled perspective view of the rotor of an Example. 2A is an end view of the rotor of FIG. 1, and FIG. 2B is an enlarged view of a part thereof. The top view of a measurement unit. The top view of the measurement unit different from FIG. The figure which shows the circuit structure of an electronic component.

The features of the embodiments described below are listed.
(Feature 1) The temperature sensor is close to the contour of the permanent magnet.
(Feature 2) The temperature sensor is approaching the circumferential end of the permanent magnet.
(Feature 3) The power generation coil and the electronic component are mounted on a flexible substrate.
(Feature 4) At least one power generation coil and one electronic component are arranged on at least one permanent magnet.

In FIG. 1, reference numeral 2 indicates a rotor, reference numeral 30 indicates a rotor core, and rotating shafts 41 and 42 are fixed to the rotor core 30. The rotor core 30 is substantially cylindrical and has four through holes 31, 32, 33, and 34 formed therein. The through holes 31, 32, 33, and 34 extend inside the rotor core 30 in parallel with the rotation axis of the rotor core 30 and open at both end surfaces of the rotor core 30 in the rotation axis direction.
As shown in FIG. 2, the through hole 31 includes a permanent magnet housing part 31 a extending in a direction orthogonal to the radius of the rotor core 30, and an air gap part 31 b extending from the permanent magnet housing part 31 a so as to be inclined outward. 31c. The permanent magnet 11 is housed and fixed in the permanent magnet housing portion 31a. The air gap portions 31b and 31c are left as a space. As disclosed in Japanese Patent Application Laid-Open No. 2011-97783, the air gap portions 31b and 31c function as flux barriers that prohibit the passage of magnetic flux and improve the rotational efficiency of the motor.

Similar to the relationship between the through hole 31 and the permanent magnet 11, the permanent magnet 12 is fixed to the through hole 32 and the flux barriers 32b and 32c are left, and the permanent magnet 13 is fixed to the through hole 33 and the flux barrier 33b, 33c is left, the permanent magnet 14 is fixed to the through hole 34, and the flux barriers 34b and 34c are left. FIG. 1 shows a state in which the permanent magnet 11 is taken out from the through hole 31, and FIG. 2 (a) shows a state in which four permanent magnets are fixed to the four through holes.
As is well known, the rotor 2 is accommodated in a space surrounded by a stator coil of the motor, and the rotating shafts 41 and 42 are rotatably supported with respect to the motor case. The rotor 2 is rotatably supported in a space surrounded by the stator coil of the motor.

  In the present embodiment, measurement units 21, 22, 23, and 24 that measure the temperature of the rotor core 30 and wirelessly transmit it outside the rotor are fixed to the rotor 30. The measurement unit 21 is inserted and fixed in the flux barrier 31c, the measurement unit 22 is inserted and fixed in the flux barrier 32c, and the measurement unit 23 is inserted and fixed in the flux barrier 33c. 24 is inserted and fixed in the flux barrier 34c.

FIG. 4 shows the measurement unit 21, in which the power generation coil 51 is formed by printed wiring on the flexible substrate 71, and the electronic component 61 is mounted on the flexible substrate 71. The power generation coil 51 and the electronic component 61 are connected. Although not shown, the same applies to the measurement units 22, 23, and 24.
FIG. 2B illustrates a state in which the measurement unit 21 is inserted and fixed to the flux barrier 31c, and the flexible substrate 71 is accommodated in the flux barrier 31c. Although not shown, the relationship between the flux barrier 32c and the measurement unit 22, the relationship between the flux barrier 33c and the measurement unit 23, and the relationship between the flux barrier 34c and the measurement unit 24 are the same.

  FIG. 5 shows a circuit configuration provided in the electronic component 61. The electronic component 61 is driven by the power from the power supply circuit 81 that converts the power supplied from the power generation coil 51 into drive power, the temperature sensor circuit 82 that is driven by the power from the power supply circuit 81, and the power from the power supply circuit 81. A transmitter circuit 83 and a transmitter antenna 84 for transmitting the measured value of the temperature sensor circuit 82 wirelessly are mounted. Although not shown, the same applies to the electronic components 62, 63, 64 mounted on the measurement units 22, 23, 24.

The power generation coil 51 is accommodated in the flux barrier 31c so that the magnetic flux leaking to the flux barrier 31c passes through the power generation coil 51. The power generating coil 51 extends along the entire length of the rotor core 30 along the rotation axis of the rotor core 30, and ensures a magnetic flux passage area of the power generating coil 51. Compared with the magnetic flux intensity generated between the permanent magnet and the stator coil, the magnetic flux intensity leaking to the flux barrier 31c is weak and it can be said that the flux barrier 31c prohibits the passage of the magnetic flux. Is very small, and the motor characteristics do not change whether or not the measurement unit is inserted into the flux barrier.
As the rotor 2 rotates, the relative positional relationship between the flux barrier 31c and the stator coil group changes, and the strength of the leakage magnetic flux changes. The power generation coil 51 generates power by changing the magnetic flux intensity. Although not shown, the same applies to the power generation coils 52, 53, 54 mounted on the measurement units 22, 23, 24.

As shown in FIG. 2B, the electronic component 61 is in close contact with the side surface (for example, the end surface in the circumferential direction) of the permanent magnet 11 and measures the temperature of the permanent magnet 11. If the temperature of the permanent magnet at the place where the temperature becomes the highest can be measured, measures for preventing the temperature rise can be accurately taken.
The flux barrier grooves 31c in which the electronic component 61 is accommodated are open on both end surfaces of the rotor 2 in the axial direction, and can receive radio waves transmitted from the electronic component 61 outside the rotor 2. Although not shown, the same applies to the electronic components 62, 63, 64 mounted on the measurement units 22, 23, 24. With the configuration of the embodiment, the temperature of the permanent magnets 11, 12, 13, and 14 can be measured and transmitted wirelessly without wiring from the outside of the rotor.
The measurement unit 21 may be as shown in FIG. In this case, a flexible substrate is not used. A thin magnet wire is wound a plurality of times to form the power generation coil 51.

  The flux barrier illustrated above is only an example and is not limited thereto. For example, Japanese Patent Application Laid-Open No. 2011-97783, Japanese Patent Application Laid-Open No. 2011-229395, Japanese Patent Application Laid-Open No. 11-89133, and the like illustrate flux barriers, and a temperature measurement unit can be accommodated in them. This embodiment is intended for an IPMSM (interior permanent magnet synchronous motor) type motor in which a permanent magnet is fixed inside a rotor core. The IPMSM type motor often has a flux barrier, and in that case, there is no need to newly provide a hole for accommodating the measurement unit. In the case of an SPMSM (surface permanent magnet synchronous motor) type motor, a flux barrier is often not provided. In the case of an SPMSM motor, the present technology can be implemented by providing a hole for accommodating a measurement unit.

Although the present embodiment has been described in detail above, these are merely examples, and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. For example, instead of installing electronic components for each permanent magnet, one electronic component can be installed in one rotor. In the latter case, one power generation coil and one electronic component can be installed in one rotor, or a plurality of power generation coils and one electronic component can be installed in one rotor. .
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2: Rotor 11, 12, 13, 14: Permanent magnets 21, 22, 23, 24: Measuring unit 30: Rotor cores 31, 32, 33, 34: Holes 31a, 32a, 33a, 34a: Permanent magnet housing portions 31b, 32b , 33b, 34b: Flux barriers 31c, 32c, 33c, 34c: Flux barriers 41, 42 for accommodating measurement units: Rotating shafts 51, 52, 53, 54: Power generation coils 61, 62, 63, 64: Electronic components 71, 72 73, 74: Flexible substrate 81: Power supply circuit 82: Temperature sensor circuit 83: Transmission circuit 84: Transmission antenna

Claims (2)

A rotor accommodated in a space surrounded by a stator coil of the motor;
A substantially cylindrical rotor core supported rotatably with respect to the stator coil, and a plurality of permanent magnets fixed inside the rotor core;
The rotor core is formed with a hole that extends in parallel with the rotation axis inside the rotor core and opens at an end surface in the rotation axis direction.
In the hole, a power generation coil extending along the hole and an electronic component connected to the power generation coil are accommodated.
The electronic component is a power supply circuit that converts power supplied from the power generation coil into drive power, a temperature sensor circuit that is driven by power from the power supply circuit, and measurement of the temperature sensor circuit that is driven by power from the power supply circuit. Equipped with a transmitter circuit that transmits values wirelessly ,
The rotor, wherein the hole is a flux barrier formed in a rotor core . The flux barrier extends along a permanent magnet;
The rotor according to claim 1 , wherein the electronic component is in contact with a permanent magnet.

Images