JP2014183606A - Rotor with temperature measurement function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in that a combination of a coil, which generates power using a change in magnetic flux density caused in a rotor during the rotation of the rotor, and an electronic component, which measures the rotor temperature and transmits it wirelessly, makes it possible to directly measure the rotor temperature without wire connection to the rotor, however, it is difficult to actually mount the coil and electronic components on the rotor.SOLUTION: A positioning projection is formed on an approximately cylindrical rotor core that fixes permanent magnets on its outer periphery, the positioning projection being used to restrict the position of the permanent magnet in contact with the end part of each of the permanent magnets. A measurement unit incorporating a power generation coil and an electronic component is fixed to each positioning projection part. The power generation coil is arranged in a place where a magnetic flux is intense, thus effectively generating power.

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 rotor core. A rotating magnetic field is generated by controlling energization of the stator coil, and the rotor is rotated by the rotating magnetic field.

  When the rotor is rotated, 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 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 put the technique to practical use.
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. It is difficult to mount the power generation coil, the temperature sensor circuit, and the transmission circuit so that each of them functions. 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 the power generation coil is accommodated in the illustrated RFID tag with a temperature sensor, the power generation coil is too small, and it is difficult to generate electric power necessary for measuring the rotor temperature and wirelessly transmitting it. .

The present specification discloses a technique for mounting a member such as a power generation coil necessary for measuring a rotor temperature and transmitting a measurement value by radio waves on the rotor.
The rotor disclosed in this specification includes a rotor core, a plurality of permanent magnets, and at least one measuring unit. The rotor core is used while being supported rotatably 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 positioning protrusions that abut the end portions of the permanent magnets and regulate the positions of the permanent magnets with respect to the rotor core. The measurement unit is fixed to the positioning convex portion. The measurement unit includes a power generation coil wound around one permanent magnet 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 measurement of the temperature sensor circuit that is driven by power from the power supply circuit. It has a transmitter circuit that transmits values wirelessly and is in contact with the end of the permanent magnet.

  According to the above, the loop formed by the power generation coil, that is, the passing range of the magnetic flux contributing to power generation is substantially equal to the size of the permanent magnet. In addition, the positioning convex part protrudes from the outer peripheral surface of the rotor, and in order to fix the measurement unit to the positioning convex part, the distance between the power generating coil and the stator is close and the power generating coil is positioned at a position where the magnetic flux strength is high. Can do. Thus, the necessary power can be generated by the power generation coil. The electronic component is disposed at a position open to the outside of the rotor, and radio waves transmitted from the transmission circuit reach the outside of the rotor. Measurement values can be received outside the rotor. In order to fix the measuring unit to the positioning convex part, the electronic component can be brought into contact with the radially outer part of the end face of the permanent magnet, and the temperature at the position where the temperature is most required is measured. be able to.

The exploded perspective view of the rotor of the 1st example. 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 top view of the rotor of FIG. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5 and a partially enlarged view thereof. The figure which contrasted an Example and a reference example. The figure corresponding to FIG. 6 of 2nd Example. The top view of the measurement unit of 2nd Example. The figure corresponding to FIG. 6 of 3rd Example. The top view of the measurement unit of 3rd Example. The figure corresponding to FIG. 6 of 4th Example. The top view of the measurement unit of 4th Example.

The features of the embodiments described below are listed.
(Feature 1) A temperature sensor is arranged in the vicinity of the contour of the permanent magnet.
(Feature 2) A temperature sensor is disposed in the vicinity of the surface of the circumferential end of the permanent magnet.
(Characteristic 3) The power generation coil is disposed closer to the front surface than the back surface of the permanent magnet.
(Feature 4) The power generation coil and the electronic component are mounted on a flexible substrate.
(Feature 5) A plurality of power generation coils and one electronic component are mounted on one flexible substrate.
(Feature 6) A plurality of power generation coils and a plurality of electronic components are mounted on one flexible substrate.
(Feature 7) One power generation coil and one electronic component are arranged in one permanent magnet.
(Feature 8) 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.
As shown in FIGS. 1, 6, etc., the permanent magnets 11, 12, 13, 14 with respect to the rotor core 30 are in contact with the circumferential end surfaces of the permanent magnets 11, 12, 13, 14 on the outer circumferential surface of the rotor core 30. Convex portions 31a, 32a, 33a, 34a, 31b, 32b, 33b, and 34b that determine the positions in the circumferential direction are formed. The convex portions 31a and 31b have the same circumferential position. The same applies to the convex portions 32a and 32b, the convex portions 33a and 33b, and the convex portions 34a and 34b. The positions of the convex portions 31a, 32a, 33a, 34a in the axial direction are the same. The same applies to the convex portions 31b, 32b, 33b, and 34b. The height of the convex portions 31a, 32a, 33a, 34a, 31b, 32b, 33b, 34b is lower than the thickness of the permanent magnets 11, 12, 13, 14, and the convex portions 31a, 32a, 33a, 34a, 31b, 32b. , 33b, 34b are recessed from the outer peripheral surface formed by the permanent magnets 11, 12, 13, 14. The top surfaces of the convex portions 31 a, 32 a, 33 a, 34 a, 31 b, 32 b, 33 b, 34 b are larger than the radius of the outer peripheral surface of the rotor core 30 and smaller than the radius of the outer peripheral surface of the permanent magnets 11, 12, 13, 14. It is formed by a part of the outer peripheral surface of the cylinder.

As shown in FIG. 1, a measurement unit 21 that measures the temperature of the rotor core 30 and wirelessly transmits it to the outside of the rotor 2 is fixed to the rotor. The measurement unit 21 includes a frame portion in which an opening that matches the contour shape of the permanent magnet 11 is formed. The part of the frame extending along the rotation shafts 41 and 42 is formed to have a thickness that fits into the interval between the permanent magnets 11 and 12 and the interval between the permanent magnets 11 and 14. It can be inserted at a position that makes a round of the surroundings. Further, the thickness of the measuring unit 21 is thinner than the difference between the thickness of the permanent magnets 11, 12, 13, 14 and the height of the convex portions 31 a, 32 a, 33 a, 34 a, 31 b, 32 b, 33 b, 34 b. When fitted into the interval between the permanent magnets 11 and 12 and the interval between the permanent magnets 11 and 14, the surface of the measurement unit 21 sinks from the outer peripheral surface formed by the permanent magnets 11, 12, 13, and 14. FIG. 1 shows a state before the measurement unit 21 is fitted in a position that makes a round around 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.

FIG. 3 shows the measurement unit 21, which is formed by forming a power generation coil 51 by printed wiring on a flexible substrate 71 and mounting an electronic component 61 on the flexible substrate 71. The electronic component 61 is connected to the power generation coil 51.
FIG. 2 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.

FIG. 5 is a plan view of the state in which the measurement unit 21 is incorporated in the rotor 2, and FIG. 6A is a cross-sectional view taken along the line VI-VI in FIG. 5. The power generation coil 51 is fitted into the interval between the permanent magnets 11 and 12 and the interval between the permanent magnets 11 and 14. The measurement unit 21 is firmly fixed to the top surfaces of the convex portions 31a, 31b, 34a, and 34b. FIG. 6B shows the relationship among the convex portion 31 a, the flexible substrate 71, the power generation coil 51, and the electronic component 61. The flexible substrate 71 is accommodated in the space between the permanent magnets 11 and 12 in a curved state, and the electronic component 61 is pressed against the end surface in the circumferential direction of the permanent magnet 11 by its elastic force.
FIG. 7A shows a case where positioning convex portions 31a, 32a, 33a, 34a, 31b, 32b, 33b, and 34b are formed, and FIG. 7B shows a case where positioning convex portions are formed. Shows the case where it is not. When the positioning convex portion is not formed, the electronic component 61 contacts the permanent magnet 11 in the vicinity of the back surface of the circumferential end surface. When the positioning convex portions 31a, 32a, 33a, 34a, 31b, 32b, 33b, and 34b are formed, the electronic component 61 comes into contact with the permanent magnet 11 in the vicinity of the surface of the end surface in the circumferential direction.
According to this embodiment, the electronic component 61 is in close contact with the vicinity of the surface of the end face in the circumferential direction of the permanent magnet 11, and measures the temperature near the surface of the end face in the circumferential direction of the permanent magnet 11. The vicinity of the surface of the end surface in the circumferential direction of the permanent magnet is the place where the temperature rises most easily, and if the temperature at that place can be measured, it becomes possible to appropriately take measures for preventing the temperature rise.
Further, when the positioning convex portions 31 a, 32 a, 33 a, 34 a, 31 b, 32 b, 33 b, 34 b are formed, the power generation coil 51 is arranged on the surface side of the permanent magnet 11 depending on the height thereof. If the convex portion is not formed, the power generation coil 51 is disposed on the back side of the permanent magnet 11. When the back side and the front side of the permanent magnet are compared, the magnetic flux intensity on the front side is higher than that on the back side. When the positioning convex portions 31a, 32a, 33a, 34a, 31b, 32b, 33b, and 34b are used, the power generation coil can be disposed at a position where the magnetic flux intensity is high, and power can be generated efficiently.

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 power can be secured by a change in strength of the magnetic flux passing through the power generation coil that is generated when the rotor 2 rotates. Further, the electronic component 61 is disposed at a position communicating with the outside of the rotor 2, and radio waves transmitted from the electronic component 61 can be received outside the rotor. According to the first embodiment, the rotor temperature can be measured and transmitted wirelessly without providing wiring between the inside and outside of the rotor.
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.
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.

(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. 8 and 9, 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.
In this embodiment, as shown in FIG. 9, 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 a single flexible substrate 70. And a set of the power generation coil 54 and the electronic component 64 are 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. 10 and 11, 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. 11, the power generation coil 51 wound around the permanent magnet 11 and the power generation coil 53 wound around the permanent magnet 13 are connected in series by the wiring 56, The total generated voltage of the power generation coils 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. 10, the outer surface side is an N pole and the inner surface side is an S pole), the power generating coils 51 and 53 are wound in the same direction. If so, the directions of the electromotive forces generated in the power generation coils 51 and 53 are aligned, and the total generated voltage is supplied to the electronic component 61. Similarly, the power generation coil 52 wound around the permanent magnet 12 and the power generation coil 54 wound around the permanent magnet 14 are connected in series by the wiring 55, and the total generated voltage of the power generation coils 52, 54 is connected. Is supplied to the electronic component 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 direction of the generated electromotive force is aligned, and 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. 12 and 13, 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 wound around the contour of the permanent magnet 11, the power generation coil 52 wound around the permanent magnet 12, and the power generation coil 53 wound around the permanent magnet 13. Then, the power generation coil 54 wound around the permanent magnet 14 is connected in series, and the total power generation 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.

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, in the above description, the embodiment has been described in which the circumferential position of the permanent magnet is contacted to determine the circumferential position. However, the measurement unit can be fixed to a convex portion that contacts the rotational axis end. The measurement unit can also be fixed to a convex portion that abuts the end in the circumferential direction and the end in the rotation axis direction. Alternatively, the permanent magnet may have an end portion that extends in both the circumferential direction and the rotation axis direction, and the measurement unit may be fixed to a convex portion that contacts the end portion.
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 31a, 32a, 33a, 34a, 31b, 32b, 33b, 34b: Convex portions 41, 42: Rotating shaft 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)

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, a plurality of permanent magnets fixed to the outer peripheral surface of the rotor core, and a measuring unit;
Positioning convex portions are formed on the rotor core so as to abut the end portions of the permanent magnets and regulate the positions of the permanent magnets with respect to the rotor core,
The measurement unit is fixed to the positioning convex part, and includes a power generation coil wound around one permanent magnet, and an electronic component connected to the power generation coil,
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 A rotor having a transmission circuit for transmitting values wirelessly and in contact with an end of a permanent magnet.

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