Temperature measurement system

Abstract

To make it easier to stably output the temperature measurement results of the magnets in the motor rotor. [Solution] The temperature measurement system 1 comprises a temperature sensor 11, a processing unit 12, and a communication unit 13. The temperature sensor 11 measures the temperature of the magnet 221 on the rotor 22 of the motor 2. The processing unit 12 generates a signal Sig1 indicating the temperature measured by the temperature sensor 11. The communication unit 13 transmits the signal Sig1 generated by the processing unit 12 to the outside of the motor 2 (encoder 3) via optical communication.

Description

Technical Field

[0001] The present disclosure relates to a temperature measurement system for measuring the temperature of a magnet included in a rotor of a motor.

Background Art

[0002] Patent Document 1 discloses an internal temperature measurement device for a motor. In this device, a temperature sensor is attached to a permanent magnet of a rotor in the motor. The temperature sensor measures the temperature of the permanent magnet using electromagnetic induction with a stator coil portion in the stator as a power source, and wirelessly transmits the measured temperature value from an antenna. A receiver installed on the stator side receives a wireless signal by its antenna and provides a temperature signal of the permanent magnet to a controller that controls the current amount of the stator coil portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a temperature measurement system that can stably output the measurement result of the temperature of a magnet included in a rotor of a motor.

Means for Solving the Problems

[0005] A temperature measurement system according to an aspect of the present disclosure includes a temperature sensor, a processing unit, and a communication unit. The temperature sensor measures the temperature of a magnet included in a rotor of a motor. The processing unit generates a signal indicating the temperature measured by the temperature sensor. The communication unit transmits the signal generated by the processing unit to the outside of the motor by optical communication.

[0006] A temperature measurement system according to one aspect of the present disclosure comprises a temperature sensor, a processing unit, and a communication unit. The temperature sensor measures the temperature of a magnet on the rotor of a motor. The processing unit generates a signal indicating the temperature measured by the temperature sensor. The communication unit transmits the signal generated by the processing unit to the outside of the motor via communication through the inside of the motor shaft. [Effects of the Invention]

[0007] According to one aspect of this disclosure, the temperature measurement system has the advantage of being able to stably output the temperature measurement result of the magnets in the rotor of a motor. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a diagram showing the schematic configuration of the temperature measurement system according to Embodiment 1. [Figure 2] Figure 2 is a diagram showing the schematic configuration of the motor according to Embodiment 1. [Figure 3] Figure 3 is a diagram showing the schematic configuration of the temperature measurement system according to Embodiment 2. [Figure 4] Figure 4 is a diagram showing the schematic configuration of the temperature measurement system according to Embodiment 3. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the drawings.

[0010] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, components, arrangement positions of components, and connection configurations shown in the following embodiments are examples only and are not intended to limit this disclosure. Furthermore, any components in the following embodiments that are not described in an independent claim will be described as optional components.

[0011] Furthermore, each figure is a schematic diagram and not necessarily a strictly accurate representation. Therefore, for example, the scale and other aspects may not necessarily match in each figure. Also, in each figure, substantially identical components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0012] Furthermore, in this specification, terms indicating relationships between elements such as orthogonal, parallel, and identical, as well as terms indicating the shape of elements such as rectangles and circles, and numerical values ​​and numerical ranges, do not represent only strict meanings, but also include substantially equivalent ranges, for example, differences of a few percent (for example, about 10%).

[0013] (Embodiment 1) The temperature measurement system 1 according to Embodiment 1 will be described below with reference to Figures 1 and 2. Figure 1 is a diagram showing the schematic configuration of the temperature measurement system 1 according to Embodiment 1. Figure 1(a) is a cross-sectional view along the axial direction of the motor 2, and Figure 1(b) is a block diagram showing the configuration of the temperature measurement system 1. Figure 2 is a diagram showing the schematic configuration of the motor 2 according to Embodiment 1. Figure 2(a) is a cross-sectional view along the axial direction of the motor 2, and Figure 2(b) is a cross-sectional view along the radial direction of the motor 2. The temperature measurement system 1 is mounted on a motor 2, such as an AC servo motor, and is a system for measuring the temperature of the magnet 221 on the rotor 22 of the motor 2.

[0014] [motor] First, the configuration of the motor 2 on which the temperature measurement system 1 according to Embodiment 1 is mounted will be explained with reference to Figure 2. In Embodiment 1, the motor 2 is an AC servo motor, and is a permanent magnet synchronous motor. In Embodiment 1, the motor 2 is configured with 4 poles and 6 slots, but the number of poles and slots are not limited to this.

[0015] As shown in Figure 2, motor 2 comprises a stator 21, a rotor 22, and a shaft 23. An encoder 3 is also mounted on the outer surface of motor 2.

[0016] The stator 21 has a housing 211, a plurality (in this case, six) of iron cores 212, and a plurality (in this case, six) of windings 213.

[0017] The housing 211 is cylindrical and forms the outer shell of the motor 2. The plurality of iron cores 212 are all cylindrical and project inward from the inner surface of the housing 211 along the radial direction of the motor 2. Each iron core 212 is integrally formed with the housing 211. The plurality of windings 213 are each formed by winding a conducting wire around a plurality of iron cores 212. An alternating current is supplied to each winding 213 from an external power source. Thereby, the combination of the iron cores 212 and the windings 213 constitutes an electromagnet.

[0018] The rotor 22 is provided at the middle part of the shaft 23 so as to cover the shaft 23. The rotor 22 has a plurality (in this case, four) of magnets 221. The plurality of magnets 221 are all permanent magnets and are arranged along the circumferential direction of the shaft 23. Also, the plurality of magnets 221 are arranged along the circumferential direction of the shaft 23 such that the outer magnetic poles of each are arranged alternately as N poles and S poles.

[0019] The shaft 23 is the part that serves as the rotation axis of the motor 2 and is provided so as to penetrate the housing 211. The rotor 22 is integrally provided at the middle part of the shaft 23. Therefore, when the rotor 22 rotates, the shaft 23 rotates along with the rotor 22. At one end of the shaft 23, a rotating plate of the encoder 3 is attached on the outer surface of the housing 211.

[0020] The encoder 3 is a rotary encoder that detects the rotation angle and speed of the motor 2. Specifically, the encoder 3 includes a circular rotary plate provided with a large number of radially elongated slits arranged in the circumferential direction, a light emitting element, and a light receiving element. The rotary plate is attached to one end of the shaft 23 of the motor 2 and rotates as the shaft 23 rotates. In the encoder 3, the light receiving element receives the light from the light emitting element. And since the light reaching the light receiving element turns on and off as the rotary plate rotates, the encoder 3 converts this on-off into a pulse signal and transmits it to a controller such as a servo amplifier. The rotation angle and speed of the motor 2 detected by the encoder 3 are used for feedback control of the motor 2.

[0021] Also, in Embodiment 1, the encoder 3 includes a receiving unit 31 that receives a signal Sig1, which is an optical signal transmitted from the communication unit 13 of the temperature measurement system 1 described later. The receiving unit 31 has a light receiving element such as a photodiode, for example, and when it receives the signal Sig1 transmitted from the communication unit 13, it converts the received optical signal into an electrical signal and outputs it. The electrical signal output by the receiving unit 31 is used by an external device of the motor 2 such as a processing unit or a controller of the encoder 3, for example.

[0022] [Temperature Measurement System] Next, the configuration of the temperature measurement system 1 according to Embodiment 1 will be described using FIG. 1. As shown in FIG. 1, the temperature measurement system 1 includes a temperature sensor 11, a processing unit 12, a communication unit 13, and a power supply unit 14. In Embodiment 1, the temperature measurement system 1 is composed of a module integrating the temperature sensor 11, the processing unit 12, the communication unit 13, and the power supply unit 14.

[0023] The temperature sensor 11 is a contact-type and electrical temperature sensor, such as a resistance temperature sensor including a resistance thermometer, linear resistor, or thermistor. The temperature sensor 11 is attached to the surface of a magnet 221 on the rotor 22 of the motor 2, and measures the temperature of the magnet 221. The temperature sensor 11 only needs to be attached to the surface of one of the multiple magnets 221. The temperature sensor 11 may be directly attached to the surface of the magnet 221, or it may be attached to the surface of the magnet 221 via a spacer or the like.

[0024] The processing unit 12 is a processing circuit having memory and a processor, and is, for example, a microcomputer. The processing unit 12 generates a signal Sig1 indicating the temperature measured by the temperature sensor 11. Specifically, the processing unit 12 receives the measurement result from the temperature sensor 11 and generates the signal Sig1 by converting the received measurement result into a binary signal. In other words, the processing unit 12 generates a signal Sig1 indicating the temperature of the magnet 221.

[0025] The communication unit 13 transmits the signal Sig1 generated by the processing unit 12 to the outside of the motor 2 via optical communication. Specifically, the communication unit 13 has a light-emitting element such as an LED (Light-Emitting Diode) or an organic EL (Electro-Luminescence) element, and transmits the signal Sig1 as an optical signal to the outside of the motor 2 by blinking the light-emitting element in response to the signal Sig1. In Embodiment 1, the outside of the motor 2 is the receiving unit 31 of the encoder 3.

[0026] The power supply unit 14 supplies operating power to the temperature sensor 11, the processing unit 12, and the communication unit 13 by energy harvesting. In other words, the power supply unit 14 supplies operating power to each part of the temperature measurement system 1 by generating power through energy harvesting. In the first embodiment of the system, the power supply unit 14 generates electricity from one of the following: vibration of the motor 2, temperature difference inside the motor 2, or light transmitted from outside the motor 2.

[0027] Specifically, for example, the power supply unit 14 may generate electricity by converting energy from the vibrations of the motor 2 into electrical power using a vibration power generation element. Alternatively, for example, the power supply unit 14 may generate electricity from the temperature gradient inside the motor 2 by using a Peltier element. Furthermore, for example, the power supply unit 14 may generate electricity by converting light transmitted from the encoder 3 located outside the motor 2 into electrical energy using a light-receiving element. In this case, the encoder 3 may further include a light-emitting element for transmitting light to the temperature measurement system 1.

[0028] [Operation] The operation of the temperature measurement system 1 according to Embodiment 1 will be described below. In the following description, it will be assumed that the motor 2 is in operation and that operating power is being supplied to the temperature measurement system 1 by the power supply unit 14. First, the temperature sensor 11 measures the temperature of the magnet 221 of the rotor 22. Then, the processing unit 12 receives the measurement result from the temperature sensor 11 and generates a signal Sig1 indicating the temperature measured by the temperature sensor 11 (i.e., the temperature of the magnet 221). The communication unit 13 then transmits the signal Sig1 generated by the processing unit 12 to the outside of the motor 2 (in this case, the encoder 3) via optical communication.

[0029] The receiver 31 of the encoder 3 receives the signal Sig1 transmitted from the communication unit 13. Here, the communication unit 13 rotates in conjunction with the rotation of the motor 2, but periodically faces the receiver 31. Therefore, the receiver 31 is able to receive the signal Sig1 transmitted by the communication unit 13. As a result, external devices of the motor 2, such as the encoder 3, can obtain the temperature measurement result of the magnet 221 inside the motor 2 in real time by receiving the signal Sig1.

[0030] [advantage] The advantages of the temperature measurement system 1 according to Embodiment 1 will be described below. As described above, the temperature measurement system 1 according to Embodiment 1 can transmit a signal Sig1 indicating the temperature of the magnet 221 measured by the temperature sensor 11 located inside the motor 2 to the outside of the motor 2. Therefore, external devices of the motor 2, such as the encoder 3, can obtain the measurement result of the temperature of the magnet 221 located inside the motor 2.

[0031] Incidentally, the motor internal temperature measuring device disclosed in Patent Document 1 also measures the temperature of the permanent magnet inside the motor and transmits the measured temperature value to a receiver located outside the motor. However, the motor internal temperature measuring device disclosed in Patent Document 1 transmits the measured temperature value to the receiver wirelessly via an antenna, that is, by radio waves. Here, since there are many metal parts such as an iron core inside the motor, there is a possibility that the transmission of the measured temperature value to the receiver may be unstable when using radio wave communication.

[0032] In contrast, the temperature measurement system 1 according to Embodiment 1 transmits a signal Sig1 indicating the temperature of the magnet 221 to the outside of the motor 2 via optical communication. Therefore, the temperature measurement system 1 according to Embodiment 1 has the advantage that even if there are many metal parts inside the motor 2, it does not affect the optical communication and can easily output stable temperature measurement results for the magnet 221 on the rotor 22 of the motor 2.

[0033] Furthermore, in the temperature measurement system 1 according to Embodiment 1, the power supply unit 14 supplies operating power to the temperature sensor 11, processing unit 12, and communication unit 13 by energy harvesting, which has the advantage of extending the operating life of the temperature measurement system 1 compared to the case where a battery is used as the operating power source.

[0034] Incidentally, the motor internal temperature measuring device disclosed in Patent Document 1 measures the temperature of the permanent magnet using electromagnetic induction between the stator coil and the stator as the power source. In other words, the motor internal temperature measuring device disclosed in Patent Document 1 is equipped with a mechanism to supply operating power to the measuring device without using a battery. However, because the motor internal temperature measuring device disclosed in Patent Document 1 uses electromagnetic induction as the power source, the measuring device may intercept the electromagnetic induction energy required when the motor is operating, causing disturbances in the magnetic field lines and potentially affecting the characteristics of the motor.

[0035] In contrast, in the temperature measurement system 1 according to Embodiment 1, the power supply unit 14 generates power from either the vibration of the motor 2, the temperature difference inside the motor 2, or light transmitted from outside the motor 2. In other words, in the temperature measurement system 1 according to Embodiment 1, the power supply unit 14 supplies operating power by energy harvesting using means other than electromagnetic induction, so the power supply unit 14 does not hijack the electromagnetic induction energy required when the motor 2 is operating, and thus has the advantage of not affecting the characteristics of the motor 2.

[0036] (Embodiment 2) The temperature measurement system 1A according to Embodiment 2 will be described below with reference to Figure 3. Figure 3 is a diagram showing the schematic configuration of the temperature measurement system 1A according to Embodiment 2. The temperature measurement system 1A according to Embodiment 2 differs from the temperature measurement system 1 according to Embodiment 1 in that it further includes an optical waveguide 15. The points that are common to the temperature measurement system 1 according to Embodiment 1 will not be explained below.

[0037] In the temperature measurement system 1A according to Embodiment 2, the temperature sensor 11, processing unit 12, communication unit 13, and power supply unit 14 are installed inside the rotor 22, rather than on the surface of the magnet 221 of the rotor 22. In Embodiment 2, the temperature sensor 11, processing unit 12, communication unit 13, and power supply unit 14 are configured as modules, similar to Embodiment 1. These modules can be embedded inside the rotor 22 during the manufacturing of the motor 2, for example, by using AM (Additive Manufacturing) technology.

[0038] The optical waveguide 15 constitutes an optical path that guides the signal Sig1 transmitted from the communication unit 13 to the outside of the rotor 22. The optical waveguide 15 can be formed in the rotor 22 during the manufacturing of the motor 2, for example, by using AM technology.

[0039] The signal Sig1 is then transmitted through the optical waveguide 15 to the outside of the motor 2 (in this case, the encoder 3). As a result, external devices of the motor 2, such as the encoder 3, can receive the signal Sig1 and obtain the temperature measurement result of the magnet 221 inside the motor 2 in real time.

[0040] As described above, in the temperature measurement system 1A according to Embodiment 2, the temperature sensor 11 is installed inside the rotor 22, making it possible to measure the temperature inside the rotor 22. Furthermore, in the temperature measurement system 1A according to Embodiment 2, by transmitting the signal Sig1 to the outside of the motor 2 using the optical waveguide 15, it is possible to stably output the measurement results of the temperature sensor 11 via optical communication, similar to Embodiment 1. Therefore, the temperature measurement system 1A according to Embodiment 2 has the advantage of being able to stably output more accurate measurement results of the temperature of the magnet 221 of the rotor 22 of the motor 2.

[0041] (Embodiment 3) The temperature measurement system 1B according to Embodiment 3 will be described below with reference to Figure 4. Figure 4 is a diagram showing the schematic configuration of the temperature measurement system 1B according to Embodiment 3. Embodiment 3 The temperature measurement system 1B differs from the temperature measurement system 1 according to Embodiment 1 in that it includes a communication unit 13A instead of a communication unit 13. The following explanation will omit details regarding points common to the temperature measurement system 1 according to Embodiment 1.

[0042] Unlike the communication unit 13 in Embodiment 1, the communication unit 13A has a communication interface that uses radio waves. The communication unit 13A transmits the signal Sig2 generated by the processing unit 12 to the outside of the motor 2 (in this case, the encoder 3) via communication through the inside of the motor 2's shaft 23. In Embodiment 3, the signal Sig2 generated by the processing unit 12 is equivalent to the signal Sig1 generated by the processing unit 12 in Embodiment 1, but because the communication method is different, it is represented here by a different code than the signal Sig1.

[0043] In Embodiment 3, the encoder 3 has a communication interface 32 for receiving the signal Sig2 from the communication unit 13A, instead of the receiving unit 31.

[0044] The signal Sig2 passes through the inside of the motor 2's shaft 23 and is transmitted to the outside of the motor 2 (in this case, the communication interface 32 of the encoder 3). As a result, external devices of the motor 2, such as the encoder 3, can receive the signal Sig2 and obtain the temperature measurement result of the magnet 221 inside the motor 2 in real time.

[0045] As described above, in the temperature measurement system 1B according to Embodiment 3, the signal Sig2 indicating the temperature of the magnet 221 is transmitted to the outside of the motor 2 via communication through the inside of the motor shaft 23. Therefore, the temperature measurement system 1B according to Embodiment 3 has the advantage that even if there are many metal parts inside the motor 2, it does not affect the communication through the inside of the shaft 23 and can easily output stable temperature measurement results for the magnet 221 on the rotor 22 of the motor 2.

[0046] (Other embodiments) Although the temperature measurement systems 1, 1A, and 1B according to Embodiments 1 to 3 have been described above, this disclosure is not limited to Embodiments 1 to 3. Without departing from the spirit of this disclosure, various modifications to Embodiments 1 to 3 that a person skilled in the art could conceive, as well as forms constructed by combining components from different embodiments, may also be included in this disclosure.

[0047] In embodiments 1 to 3, the temperature measurement systems 1, 1A, and 1B are equipped with a power supply unit 14, but are not limited to this. For example, the temperature measurement systems 1, 1A, and 1B may be equipped with a battery instead of a power supply unit 14. In this case, the temperature sensor 11, the processing unit 12, and the communication units 13 and 13A are supplied with operating power from the battery.

[0048] In embodiments 1 to 3, the temperature sensor 11 is a resistance temperature sensor, but is not limited to this. For example, the temperature sensor 11 may be a thermocouple or an IC (Integrated Circuit) type temperature sensor.

[0049] In embodiments 1 and 2, the temperature measurement system 1,1A is composed of a module integrating a temperature sensor 11, a processing unit 12, a communication unit 13, and a power supply unit 14, but is not limited to this. For example, in the temperature measurement system 1,1A, the temperature sensor 11, processing unit 12, communication unit 13, and power supply unit 14 may be arranged separately from each other. Also, in embodiment 3, the temperature sensor 11, processing unit 12, and power supply unit 14 in the temperature measurement system 1B may be composed of a module integrating each other, or they may be arranged separately from each other.

[0050] (summary) As described above, the temperature measurement system 1,1A according to the first embodiment comprises a temperature sensor 11, a processing unit 12, and a communication unit 13. The temperature sensor 11 measures the temperature of the magnet 221 on the rotor 22 of the motor 2. The processing unit 12 generates a signal Sig1 indicating the temperature measured by the temperature sensor 11. The communication unit 13 transmits the signal Sig1 generated by the processing unit 12 to the outside of the motor 2 (encoder 3) via optical communication.

[0051] This configuration has the advantage that, since the signal Sig1 indicating the temperature of the magnet 221 is transmitted to the outside of the motor 2 via optical communication, the presence of many metal parts inside the motor 2 does not affect the optical communication, and the measurement results of the temperature of the magnet 221 on the rotor 22 of the motor 2 can be output stably.

[0052] Furthermore, the temperature measurement system 1,1A according to the second embodiment further includes a power supply unit 14 that supplies operating power to the temperature sensor 11, the processing unit 12, and the communication unit 13 by generating power through energy harvesting, as in the first embodiment.

[0053] With this configuration, the power supply unit 14 supplies operating power to the temperature sensor 11, processing unit 12, and communication unit 13 by energy harvesting, which has the advantage of extending the operating life of the temperature measurement system 1 compared to when a battery is used as the operating power source.

[0054] Furthermore, in the temperature measurement system 1,1A according to the third embodiment, the power supply unit 14 generates power from one of the following: vibration of the motor 2, temperature difference inside the motor 2, or light transmitted from outside the motor 2.

[0055] This configuration has the advantage that, since operating power is supplied by energy harvesting using means other than electromagnetic induction, the power supply unit 14 does not intercept the electromagnetic induction energy required when the motor 2 is operating, and thus is less likely to affect the characteristics of the motor 2.

[0056] Furthermore, in the temperature measurement system 1A according to the fourth embodiment, in any one of the first to third embodiments, the temperature sensor 11, the processing unit 12, and the communication unit 13 are installed inside the rotor 22. The temperature measurement system 1A further includes an optical waveguide 15 that guides the signal Sig1 transmitted from the communication unit 13 to the outside of the rotor 22. The signal Sig1 is transmitted to the outside of the motor 2 (encoder 3) by passing through the optical waveguide 15.

[0057] With this configuration, since the temperature sensor 11 is installed inside the rotor 22, it is possible to measure the temperature inside the rotor 22, which has the advantage of being able to stably output more accurate measurement results of the temperature of the magnet 221 on the rotor 22 of the motor 2.

[0058] Furthermore, the temperature measurement system 1B according to the fifth embodiment includes a temperature sensor 11, a processing unit 12, and a communication unit 13A. The temperature sensor 11 measures the temperature of the magnet 221 on the rotor 22 of the motor 2. The processing unit 12 generates a signal Sig2 indicating the temperature measured by the temperature sensor 11. The communication unit 13 transmits the signal Sig2 generated by the processing unit 12 to the outside of the motor 2 (encoder 3) via communication through the inside of the shaft 23 of the motor 2.

[0059] This configuration has the advantage that, even if there are many metal parts inside the motor 2, it does not affect the communication through the shaft 23, and it is easy to stably output the temperature measurement result of the magnet 221 on the rotor 22 of the motor 2. [Industrial applicability]

[0060] This disclosure is useful as a system for measuring the temperature of the magnets in the rotor of a motor. [Explanation of Symbols]

[0061] 1,1A,1B Temperature Measurement System 11. Temperature sensor 12 Processing Units 13,13A Communications Department 14 Power supply section 15 Optical waveguide 2 motors 21 status 211 cabinets 212 Iron Heart 213 Winding 22 rotors 221 Magnet 23 Shaft 3 encoders 31 Receiver 32 Communication Interfaces Sig1,Sig2 signal

Claims

1. A temperature sensor that measures the temperature of the magnets in the motor rotor, A processing unit that generates a signal indicating the temperature measured by the temperature sensor, The system includes a communication unit that transmits the signal generated by the processing unit to the outside of the motor via optical communication. Temperature measurement system.

2. The system further includes a power supply unit that supplies operating power to the temperature sensor, processing unit, and communication unit by energy harvesting. The temperature measurement system according to claim 1.

3. The power supply unit generates electricity from one of the following: vibration of the motor, temperature difference inside the motor, or light transmitted from outside the motor. The temperature measurement system according to claim 2.

4. The temperature sensor, the processing unit, and the communication unit are installed inside the rotor. The system further includes an optical waveguide that guides the signal transmitted from the communication unit to the outside of the rotor, The signal is transmitted to the outside of the motor by passing through the optical waveguide. A temperature measurement system according to any one of claims 1 to 3.

5. A temperature sensor that measures the temperature of the magnets in the motor rotor, A processing unit that generates a signal indicating the temperature measured by the temperature sensor, The system includes a communication unit that transmits the signal generated by the processing unit to the outside of the motor via communication through the inside of the motor shaft. Temperature measurement system.

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