JP5995764B2 - Rotor with temperature measurement function - Google Patents

Description

  The present specification discloses a technique related to a rotor that is rotatably supported 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 outer peripheral surface of 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 is demagnetized or demagnetized when the temperature rises above a predetermined temperature, the torque of the motor 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 includes 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 from the power supply circuit. It is equipped with a transmitter circuit that is driven and wirelessly transmits measurement values from 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

Although the technique of Patent Document 1 can in principle measure the rotor temperature without connecting to the rotating rotor, it is difficult to implement 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. In order to generate power using a small change in magnetic flux intensity, the mounting posture of the power generation coil with respect to the rotor 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 the technique of Patent Document 1, only the installation position of the RFID tag with the temperature sensor is illustrated, and there is no disclosure about the method of arranging the power generation coil. If a power generation coil is accommodated in the illustrated RFID tag with a temperature sensor, the power generation coil is too small to generate power necessary for wireless transmission by measuring the rotor temperature. .

In the present specification, a technique for mounting a member necessary for measuring a rotor temperature such as a power generation coil and transmitting a measurement value by radio waves to the rotor 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 outer peripheral surface of the rotor core. The rotor core is formed with a groove extending inside the contour along the contour of at least one permanent magnet, and a power generation coil and an electronic component connected to the power generation coil are accommodated in the groove. 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 a temperature sensor circuit that is driven by power from the power supply circuit. A transmitter circuit for transmitting measurement values wirelessly is installed. The rotor is used in a state of being accommodated in a space surrounded by the stator coil.

  According to the above, the magnetic flux passage area of the power generation coil is approximately equal to the size of the permanent magnet, and a size capable of generating the required power is ensured. In addition, the outer sides of the power generation coil and the electronic component are covered with permanent magnets, and even if a strong centrifugal force acts on the power generation coil, the power generation coil or the like is not scattered. Further, the transmission circuit is housed in a groove communicating with the outside of the rotor, and radio waves transmitted from the transmission circuit reach the outside of the rotor through the groove. Measurement values can be received outside the rotor.

The exploded perspective view of the rotor of the 1st example. The top view of the rotor of FIG. III-III sectional view taken on the line of FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 2. The top view of a measurement unit. The top view of the state in which the measurement unit is accommodated in the groove | channel of a rotor core. The figure corresponding to FIG. 4 in the state in which the measurement unit is accommodated in the groove | channel of a rotor core. The figure which shows the relationship between a groove | channel, a flexible substrate, an electronic component, and a power generation coil. The figure which shows the circuit structure of an electronic component. The top view of a measurement unit. The top view of the measurement unit different from FIG. The disassembled perspective view of the rotor of 2nd Example. The figure corresponding to FIG. 7 of 2nd Example. The top view of the measurement unit of 2nd Example. The figure corresponding to FIG. 7 of 3rd Example. The top view of the measurement unit of 3rd Example. The figure corresponding to FIG. 7 of 4th Example. The top view of the measurement unit of 4th Example.

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) A plurality of power generation coils and one electronic component are mounted on one flexible substrate.
(Feature 5) A plurality of power generation coils and a plurality of electronic components are mounted on one flexible substrate.
(Feature 6) One power generation coil and one electronic component are arranged in one permanent magnet.
(Feature 7) A plurality of power generation coils and one electronic component are arranged for a plurality of permanent magnets. The plurality of power generation coils are connected in series so that the directions of the electromotive forces are aligned.

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 has a substantially cylindrical shape, and four permanent magnets 11, 12, 13, and 14 are fixed to the outer peripheral surface thereof. In the figure, a state before one permanent magnet 11 is fixed to the rotor core 30 is shown.
In the present embodiment, a measurement unit 21 that measures the temperature of the rotor core 30 and wirelessly transmits it to the outside of the rotor is fixed to the rotor. The rotor core 30 is formed with a groove 31 for accommodating the measurement unit 21. The groove 31 is formed by grooves 31b and 31d extending in the axial direction on the outer peripheral surface of the rotor core 30, and grooves 31a and 31c extending in the circumferential direction between the grooves 31b and 31d at the axial end of the rotor core 30. A circular groove 31 is formed by the grooves 31a, 31b, 31c, and 31d. The permanent magnet 11 is fixed to the rotor core 30 in a state where the measurement unit 21 is accommodated in the groove 31. The groove 31 extends along the contour of the permanent magnet 11. Precisely speaking, the groove 31 extends inside the contour of the permanent magnet 11. When the permanent magnet 11 is fixed to the outer peripheral surface of the rotor core 30, the measurement unit 21 and the groove 31 are covered with the permanent magnet 11.
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.
2 shows a plan view of the core 2 in the state shown in FIG. 1, FIG. 3 shows a cross section taken along line III-III in FIG. 2, and FIG. 4 shows a cross section taken along line IV-IV in FIG. . Note that the measurement unit 21 is not shown in FIGS.

FIG. 5 shows the measurement unit 21, which is composed of a power generation coil 51 and an electronic component 61 connected to the power generation coil 51. The power generating coil 51 is configured by winding a single conductive wire a plurality of times, and electronic components 61 are connected to both ends of the conductive wire. The power generating coil 51 is formed in a shape in which the conductive wire is wound along the contour of the permanent magnet while being accommodated in the groove 31. Further, the electronic component 61 is set at a position and a size to be accommodated in the groove 31b.
As shown in FIG. 11, the measurement unit 21 can be formed by forming a power generation coil 51 by performing printed wiring on a flexible substrate 71 and mounting an electronic component 61 on the flexible substrate 71. FIG. 7 is a diagram corresponding to FIG. 4 in a state in which the measurement unit 21 is incorporated in the rotor 2. FIG. 8 shows the relationship among the flexible substrate 71, the power generation coil 51, the electronic component 61, the groove 31 b, and the permanent magnet 11. The flexible substrate 71 is accommodated in the groove 31b in a curved state, and the electronic component 61 is pressed against the inner surface of the permanent magnet 11 by its elastic force.

  FIG. 9 shows a circuit configuration provided in the electronic component 61. The electronic component 61 is driven by power from a power supply circuit 81 that converts power supplied from the power generation coil 51 into drive power, a temperature sensor circuit 82 that is driven by power from the power supply circuit 81, and power from the power supply circuit 81. In addition, a transmission circuit 83 and a transmission antenna 84 that wirelessly transmit the measurement value of the temperature sensor circuit 82 are mounted.

As shown in FIG. 8, the electronic component 61 is in close contact with the circumferential end of the permanent magnet 11 and measures the temperature of the circumferential end of the permanent magnet 11. The end of the permanent magnet in the circumferential direction is the place where the temperature rises most easily, and if the temperature at that place can be measured, it is possible to take appropriate measures to prevent the temperature rise.
The magnetic flux passage area of the power generation coil 51 is substantially equal to the area of the permanent magnet 11, and is approximately ¼ of the outer peripheral area of the cylindrical portion of the rotor core 30. The effective power generation area of the power generation coil 51 is wide, and necessary electric power can be ensured by the change in the magnetic flux intensity passing through the power generation coil 51 generated by the rotation of the rotor 2.
The groove 31b in which the electronic component 61 is accommodated communicates with the outside of the rotor 2 and can receive radio waves transmitted from the electronic component 61 outside the rotor 2. According to the first embodiment, the rotor temperature can be measured and transmitted wirelessly without wiring from outside 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 a power generation coil 51.

The size of the power generating coil 51 is preferably approximately equal to the size of one permanent magnet. As is well known, the magnitude of the generated voltage v is as follows according to the law of electromagnetic induction.
v = −n × (ΔB / Δt) × S
Here, n is the number of turns of the coil, ΔB / Δt is the time change of the magnetic flux density, and S is the area of the coil.
From the above equation, it can be seen that the generated voltage v and the coil area S are proportional, and it is found effective to increase the coil area in order to increase the generated voltage. However, when the size of the power generation coil is larger than one permanent magnet, the power generation coil is also applied to the adjacent permanent magnet. However, because the polarity of adjacent permanent magnets is in the opposite direction and cancels the magnetic flux, when one power generation coil reaches the adjacent permanent magnet, the magnetic flux passing through that power generation coil is reduced. End up. As a result, the generated voltage decreases. When the power generation coil is approximately equal to the size of one permanent magnet, power can be generated most efficiently.

(Second embodiment)
In the first embodiment, the measurement unit 21 is arranged only for one of the four permanent magnets 11, 12, 13, 14.
In the second embodiment, as illustrated in FIGS. 12 and 13, a measurement unit is arranged in each permanent magnet. That is, the measurement unit 21 is arranged on the permanent magnet 11, the measurement unit 22 is arranged on the permanent magnet 12, the measurement unit 23 is arranged on the permanent magnet 13, and the measurement unit 24 is arranged on the permanent magnet 14. For this purpose, a groove 31 extending inside the contour is formed along the contour of the permanent magnet 11, and the measurement unit 21 is accommodated in the groove 31. A groove 32 extending inside the contour is formed along the contour of the permanent magnet 12, and the measurement unit 22 is accommodated in the groove 32. A groove 33 extending inside the contour is formed along the contour of the permanent magnet 13, and the measurement unit 23 is accommodated in the groove 33. A groove 34 extending inside the contour is formed along the contour of the permanent magnet 14, and the measurement unit 24 is accommodated in the groove 34. In this embodiment, the temperature of the permanent magnet 11 is measured by the electronic component 61 and transmitted. The temperature of the permanent magnet 12 is measured by the electronic component 62 and transmitted. The temperature of the permanent magnet 13 is measured by the electronic component 63 and transmitted. The temperature of the permanent magnet 14 is measured by the electronic component 64 and transmitted. The temperature for each permanent magnet can be measured.
In this embodiment, as shown in FIG. 14, a set of a power generation coil 51 and an electronic component 61, a set of a power generation coil 52 and an electronic component 62, a power generation coil 53 and an electronic component 63 are formed on one flexible substrate 70. And a set of the power generation coil 54 and the electronic component 64 can be formed. If one flexible substrate 70 is used, the measurement units 21, 22, 23, and 24 are easy to manufacture and attach to the rotor core 30.

(Third embodiment)
In this embodiment, as shown in FIGS. 15 and 16, the temperature of the permanent magnet 11 is measured and transmitted by the electronic component 61, and the temperature of the permanent magnet 12 is measured and transmitted by the electronic component 62. In the present embodiment, as shown in FIG. 16, a power generation coil 51 that extends inside the contour of the permanent magnet 11 and a power generation coil 53 that extends inside the contour of the permanent magnet 13 are connected in series by a wiring 56. The total generated voltage of 51 and 53 is supplied to the electronic component 61. The power generating coils 51 and 53 are wound in the same direction. Since the permanent magnet 11 and the permanent magnet 13 have the same polarity (in the case shown in FIG. 15, the outer surface side has the N pole and the inner surface side has the S pole polarity), the power generating coils 51 and 53 are wound in the same direction. Then, the total generated voltage of the power generation coils 51 and 53 is supplied to the electronic component 61. Similarly, the power generation coil 52 extending inside the contour of the permanent magnet 12 and the power generation coil 54 extending inside the contour of the permanent magnet 14 are connected in series by the wiring 55, and the total generated voltage of the power generation coils 52 and 54 is converted into an electron. Supply to part 62. The power generating coils 52 and 54 are wound in the same direction. Since the permanent magnet 12 and the permanent magnet 14 have the same polarity (opposite polarity with respect to the permanent magnets 11 and 13), if the power generating coils 52 and 54 are wound in the same direction, the power generating coils 52 and 54 The total generated voltage is supplied to the electronic component 62. Also in the present embodiment, the power generation coils 51, 52, 53, and 54 are printed on one common substrate 70, and the electronic components 61 and 62 are mounted.

(Fourth embodiment)
In this embodiment, as shown in FIGS. 17 and 18, the temperature of the permanent magnet 11 is measured by the electronic component 61 and transmitted. In the present embodiment, the power generation coil 51 that extends inside the contour of the permanent magnet 11, the power generation coil 52 that extends inside the contour of the permanent magnet 12, the power generation coil 53 that extends inside the contour of the permanent magnet 13, and the permanent magnet 14. Are connected in series, and the total generated voltage of the power generation coils 51, 52, 53, 54 is supplied to the electronic component 61. The permanent magnet 11 and the permanent magnet 13 have the same polarity, the permanent magnet 12 and the permanent magnet 14 have the same polarity, and the permanent magnets 11 and 13 and the permanent magnets 12 and 14 have opposite polarities. The power generation coil 53 is wound in the same direction, the power generation coil 52 and the power generation coil 54 are wound in the same direction, and the power generation coils 51 and 53 and the power generation coils 52 and 54 are wound in opposite directions. When connected as described above, the directions of the electromotive forces generated in the power generation coils 51, 52, 53, 54 are aligned, and the total generated voltage of the power generation coils 51, 52, 53, 54 is supplied to the electronic component 61. Also in this embodiment, the power generation coils 51, 52, 53, and 54 are printed on one common substrate 70, and the electronic component 61 is mounted.

  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: Grooves 41, 42: Rotating shafts 51, 52, 53, 54: Power generation Coils 61, 62, 63, 64: Electronic components 70, 71: Flexible substrate 81: Power supply circuit 82: Temperature sensor circuit 83: Transmission circuit 84: Transmission antenna

Claims (1)

It is a rotor that is housed and used in a space surrounded by a stator coil of a motor,
A substantially cylindrical rotor core supported rotatably with respect to the stator coil, and a plurality of permanent magnets fixed to the outer peripheral surface of the rotor core;
A groove extending inside the contour along the contour of at least one permanent magnet is formed in the rotor core,
The groove accommodates a power generation coil and an electronic component connected to the power generation coil.
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 a power sensor that is driven by power from the power supply circuit. A rotor that is equipped with a transmitter circuit that transmits measurement values wirelessly.

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