Non-contact power supply rotary electric machine

Abstract

To provide a rotary electric machine which can sufficiently supply cooling oil to a part requiring cooling such as a coil end.SOLUTION: A rotary electric machine has a measurement device 102 provided in a rotor 10 and measuring a state of the rotor 10 to be outputted, a power reception coil 16 provided in the rotor 10 and supplying power to the measurement device 102, and a power transmission coil 24 wound in a toric manner along a circumferential direction of a revolving shaft of the rotor 10 and supplying power to the power reception coil 16 in a non-contact manner. An injection hole 18 for supplying cooling oil to a rotor shaft 12 is provided, and the power reception coil 16 is arranged in a radial direction of the rotor 10 at the position not overlapping with the injection hole 18.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotating electric machine capable of receiving power in a contactless manner. [Background technology]

[0002] In permanent magnet synchronous motors, which are widely used as rotating electrical machines such as traction motors, when the magnets become hot, the current passing through the coils creates a reverse magnetic field, causing irreversible demagnetization of the magnets. This can lead to a deterioration in motor performance. It is particularly important to manage the temperature of the magnets, as once irreversible demagnetization occurs, the magnets cannot be restored to their original magnetic force.

[0003] Ordinary rotating electric machines are designed to have a margin above the upper limit temperature to prevent irreversible demagnetization, so that they can be used safely without reaching the upper limit temperature. Therefore, if it were possible to directly measure the magnet temperature, the current that can be passed through the coil could be adjusted according to the measured magnet temperature, making it possible to pass a higher current and use the rotating electric machine to the limit of its characteristics.

[0004] To address this issue, a known configuration uses slip rings to provide electrical contact between the rotating side (rotor) and fixed side (stator) of a rotating electrical machine, transmitting measurement data from a temperature sensor attached to a magnet inside the rotor to an external device such as the stator. However, this has problems such as wear at the contact points shortening the life of the rotating electrical machine and increased friction due to the contact, worsening losses in the rotating electrical machine.

[0005] Therefore, in the prior art, a method has been proposed in which a measuring device including a measuring instrument and a data transmission device is installed on the rotor to measure the temperature inside the rotor without contact, and power is supplied to the measuring device. For example, a technology has been disclosed in which a doughnut-shaped power receiving coil provided on the rotor and a doughnut-shaped power transmitting coil provided on the stator are arranged opposite each other to transmit power without contact, and a high-frequency current is passed through the power transmitting coil from the outside to supply power to the power receiving coil without contact. Known configurations for arranging the power receiving coil and the power transmitting coil facing each other include arranging them in the direction of the rotation axis or in the radial direction (Patent Documents 1 to 3, etc.). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-064985 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-101485 [Patent Document 3] Patent Publication No. 2021-013217 Summary of the Invention [Problem to be solved by the invention]

[0007] Rotating electric machines employ a cooling structure that uses cooling oil to lower the temperature of the rotor and stator. For example, cooling oil flows through a hollow oil passage at the center of the rotor shaft, which is the rotating axis of the rotor. Radial injection holes are drilled in parts of the shaft, and the cooling oil is sprayed outward from the injection holes by centrifugal force. The cooling oil can be cooled by splashing onto the rotor end plates and the stator coil ends, etc.

[0008] However, when a mechanism for supplying power to a rotating electric machine without contact is installed, the relative positional relationship between the receiving coil provided on the rotor and the injection hole for supplying cooling oil is not taken into consideration, which causes the cooling oil supplied from the injection hole to be obstructed by the receiving coil, resulting in a problem in which cooling oil is not sufficiently supplied to areas where it is needed, such as the coil ends. [Means for solving the problem]

[0009] One aspect of the present invention is a rotating electric machine that rotates a rotor, comprising: a measuring device provided on the rotor that measures and outputs the state of the rotor; a receiving coil provided on the rotor that supplies power to the measuring device; and a transmitting coil that is wound in a circular shape around the circumferential direction of the rotor's rotation axis and supplies power to the receiving coil without contact, wherein an injection hole is provided for supplying cooling oil to the rotor shaft, and the receiving coil is positioned along the radial direction of the rotor so as not to overlap with the injection hole.

[0010] Here, it is preferable that the power receiving coil has an arc shape along the circumferential direction of the rotation axis of the rotor.

[0011] Preferably, a plurality of the power receiving coils are arranged in a line along the circumferential direction of the rotation axis of the rotor.

[0012] Preferably, the power receiving coil is provided with a magnetic shield layer on the opposite side to the power transmitting coil. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a rotating electrical machine that can supply sufficient cooling oil to areas that require cooling, such as coil ends. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram showing a configuration of a rotating electric machine according to an embodiment of the present invention; [Figure 2]1 is a diagram showing a configuration of a rotating electric machine (cross section of line CC) according to an embodiment of the present invention. [Figure 3] 1 is a diagram showing the configuration of a rotating electric machine (cross section taken along line DD) according to an embodiment of the present invention. [Figure 4] 1 is a diagram showing the configuration of a rotating electric machine (cross section taken along line AA) according to an embodiment of the present invention. [Figure 5] 1 is a diagram showing a configuration of a rotating electric machine (cross section taken along line BB) according to an embodiment of the present invention. [Figure 6] 10A and 10B are diagrams illustrating results of a magnetic field analysis according to an embodiment of the present invention. [Figure 7] 1 is a diagram showing the configuration of a rotating electric machine (cross section taken along line AA) according to an embodiment of the present invention. [Figure 8] 10A and 10B are diagrams illustrating results of a magnetic field analysis according to an embodiment of the present invention. [Figure 9] 5A and 5B are diagrams illustrating a supply state of cooling oil in the embodiment of the present invention. [Figure 10] 4 is a diagram showing another example of the configuration of a rotating electric machine according to an embodiment of the present invention (cross section taken along line AA). FIG. [Figure 11] 4 is a diagram showing another example of the configuration of a rotating electric machine according to an embodiment of the present invention (cross section taken along line AA). FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] As shown in Figures 1 to 5, a rotating electric machine 100 in an embodiment of the present invention includes a rotor 10, a rotor shaft 12, a stator 14, a receiving coil 16, an injection hole 18, a bearing 20, a housing case 22, a transmitting coil 24, a sensor 30, a measuring instrument 32, an output device 34, an armature coil 36, and a current controller 38.

[0016] A measuring device 102 that measures and outputs the rotor state is installed on the rotor 10. The measuring device 102 is composed of a measuring instrument 32 that measures data from a sensor 30 that senses the rotor state, and an output device 34 that outputs the obtained data to the outside. The measuring device 102 is used in combination with a power supply unit 104 that can contactlessly supply the power required for operation. The measuring device 102 may also be equipped with a battery or capacitor as a power buffer to stabilize operation. The output device 34 functions as a transmitter that sends data measured by the rotor 10 to the stator side, etc. The output device 34 can be, for example, a wired system in which a cable is connected when the rotor is stopped to send measurement data, or a wireless data transmission system in which a data transmission antenna is installed in the output device 34 and a data receiving antenna is installed on the stator side, etc., for communication. By feeding back measurement data received on the stator side or the like to a current controller 38 (such as an inverter) for the armature coil 36 of the stator 14, it is possible to appropriately control the current flowing through the armature coil 36, for example, in accordance with data measured by the rotor. This allows for a higher current to be passed through, enabling the rotating electric machine to be used to its full potential. The sensor 30 that senses the rotor state is not limited to a temperature sensor that senses the magnet temperature inside the rotor, but may also be a sensor that can sense state quantities such as strain, acceleration, voltage, and magnetic flux. Well-known examples of the measuring device 102 that includes a measuring device 32 and an output device 34 include a telemeter that can transmit data measured by the measuring device 32 to an external device in real time from the output device 34, such as an antenna, and a data logger that can record data measured by the measuring device 32 on a recording medium inside the measuring device and then transmit the data to an external device via the output device 34 after measurement.

[0017] The measuring device 102 can measure the temperature of the magnets installed in the rotor 10 using a temperature sensor such as a thermocouple or a thermistor. However, the sensor 30 is not limited to a temperature sensor and can also be a strain sensor, acceleration sensor, voltage sensor, magnetic flux sensor, etc. Using a strain sensor allows direct measurement of mechanical stress within the rotor, making it possible to predict damage to the rotor 10 during rotation. Attaching a strain sensor to the rotor shaft 12 allows direct measurement of motor torque from the torsion of the shaft. Using an acceleration sensor allows measurement of vibration caused by the rotor 10. Using a voltage sensor allows measurement of the shaft voltage generated in the rotor 10, making it possible to predict the occurrence of electrolytic corrosion, which can cause bearing failure. Measuring magnetic flux using a Hall sensor or detection coil as a magnetic flux sensor and feeding it back to the current controller 38 enables current control that achieves uniform magnetic flux and reduces torque ripple, etc. In this way, measuring the state of the rotor 10 using the measuring device 102 can achieve a variety of effects.

[0018] 2 to 5 show the configuration of the rotating electric machine 100. Fig. 2 is a cross-sectional view of a plane perpendicular to the rotation axis of the rotating electric machine 100, taken along line CC in Figs. 4 and 5. Fig. 3 is a cross-sectional view of a plane perpendicular to the rotation axis of the rotating electric machine 100, taken along line DD in Figs. 4 and 5. Fig. 4 is a cross-sectional view of a plane parallel to the rotation axis of the rotating electric machine 100, taken along line AA in Fig. 2. Fig. 5 is a cross-sectional view of a plane parallel to the rotation axis of the rotating electric machine 100, taken along line BB in Fig. 2.

[0019] The rotor 10 is a part that rotates in the rotating electric machine 100. The rotor 10 is configured to include a rotor permanent magnet, a rotor core made of electromagnetic steel sheets, and a rotor shaft 12. The rotor shaft 12 is used to transmit the rotational torque output from the rotor 10 to the outside of the rotating electric machine 100. The rotor shaft 12 is attached to a housing case 22 via bearings 20. This allows the rotor 10, including the rotor shaft 12, to rotate relative to the housing case 22.

[0020] The stator 14 is a part of the rotary electric machine 100 that is stationary relative to the rotor 10. The stator 14 includes an armature coil 36 and a stator core made of electromagnetic steel sheets. The rotor 10 and the stator 14 are housed in a casing.

[0021] The rotor shaft 12 has a hollow shaft shape. The rotor shaft 12 is used as a cooling oil supply pipe by utilizing the hollow portion. The rotor shaft 12 is provided with injection holes 18 for injecting cooling oil. The injection holes 18 are drilled so as to penetrate the rotor shaft 12 in the radial direction from the inner peripheral surface to the outer peripheral surface. The cooling oil is injected from the injection holes 18 in the radial direction of the rotor 10 by centrifugal force generated by the rotation of the rotor 10.

[0022] The ejection holes 18 are provided at positions where cooling oil is supplied to areas of the rotating electric machine 100 that require cooling. For example, it is preferable to provide the ejection holes 18 at positions along the axial direction of the rotor shaft 12 where the cooling oil will spray onto the coil ends 36a of the armature coils 36 of the stator 14. In this way, the cooling oil ejected from the ejection holes 18 is supplied to areas of the rotating electric machine 100 that require cooling.

[0023] In the present embodiment, the rotating electric machine 100 is configured to have two ejection holes 18, but the present invention is not limited to this and may have one or three or more ejection holes 18. Furthermore, the position at which the ejection holes 18 are provided may be changed as appropriate as long as the positional relationship with the power receiving coil 16 described below is satisfied.

[0024] The power receiving coil 16 is provided on the rotor 10. In this embodiment, the power receiving coil 16 is provided on the axial end of the rotor 10, for example, on the end surface of the end plate 10a. The power receiving coil 16 is preferably arranged so that the open surface of the coil faces the axial direction of the rotor shaft 12. The power receiving coil 16 is connected to a measuring device 102 so that the induced power generated therein can be supplied. The measuring device 102 is also provided on the rotor 10. The measuring device 102 is provided, for example, inside the end plate 10a.

[0025] The power transmitting coil 24 is provided in the housing case 22. In this embodiment, the power transmitting coil 24 is wound coaxially with the rotation axis of the rotor 10. For example, the power transmitting coil 24 is wound around the outer periphery of the cylindrical housing case 22. The power transmitting coil 24 is disposed at a position spaced apart from the power receiving coil 16 along the direction of the rotation axis of the rotor 10.

[0026] The power transmitting coil 24 is arranged so that the magnetic field generated when an AC excitation current, such as a sinusoidal current, is passed through it interlinks with the power receiving coil 16. When an excitation current is passed through the power transmitting coil 24, a magnetic field is generated that circulates around the conductor that makes up the power transmitting coil 24, as shown in the magnetic field analysis results in Fig. 6. By placing the power receiving coil 16 in a position facing the power transmitting coil 24 along the rotational axis direction of the rotor shaft 12, the magnetic field generated by the power transmitting coil 24 can be made to interlink with the power receiving coil 16, as shown in Fig. 6.

[0027] When the rotating electric machine 100 is driven and the rotor 10 is rotating, the distance of the power receiving coil 16 from the central axis of rotation of the rotor 10 in the radial direction does not change. Because the power transmitting coil 24 is wound coaxially with the rotational axis of the rotor 10, the relative positional relationship between the power receiving coil 16 and the power transmitting coil 24 in the radial direction does not change regardless of changes in the phase (rotation angle) of the power receiving coil 16 that accompany the rotation of the rotor 10. Furthermore, the magnetic field generated by the power transmitting coil 24 does not change along the circumferential direction of the rotor 10. Therefore, as the rotor 10 rotates, the magnetic linkage between the power receiving coil 16 and the power transmitting coil 24 does not change, and the induced power generated in the power receiving coil 16 does not change either. Therefore, when the rotor 10 is rotating, the linkage between the magnetic field generated by the power transmitting coil 24 and the power receiving coil 16 does not change, and induced power is stably generated in the power receiving coil 16 regardless of the rotation angle of the rotor 10. This allows stable power supply from the power receiving coil 16 to the measuring device 102.

[0028] If DC power is required in the measuring device 102, a rectifying circuit may be provided in the measuring device 102 to rectify the AC electromotive force generated in the power receiving coil 16.

[0029] As shown in FIG. 7 , a magnetic shield 26 is preferably provided on the rear side of the power receiving coil 16, i.e., on the opposite side of the power transmitting coil 24 along the rotation axis. The magnetic shield 26 is preferably made of a material that has a higher magnetic permeability, allowing magnetic flux to pass more easily, and a higher electrical resistivity, making it less likely to generate eddy currents, than the material constituting the end plates 10a of the rotor 10. The magnetic shield 26 is preferably made of a magnetic material, such as a ferrite core. As shown in the magnetic field analysis results in FIG. 8 , providing the magnetic shield 26 increases the magnetic flux linking the power receiving coil 16. This increases the induced power generated in the power receiving coil 16. It also prevents magnetic flux leakage to the rotor 10 on the rear side of the power receiving coil 16. This suppresses eddy currents in the rotor permanent magnets and magnetic steel sheets of the rotor core on the rear side of the rotor 10 due to the leakage magnetic flux.

[0030] 2 and the perspective view of FIG. 9, the power receiving coil 16 and the measuring device 102 are arranged in positions along the radial direction of the rotor 10 so as not to overlap with the injection holes 18. In other words, the power receiving coil 16 is arranged to avoid a position where the cooling oil injected radially from the injection holes 18 would be blocked by the power receiving coil 16 and would not be sufficiently supplied to the areas of the rotating electric machine 100 that require cooling. This allows the areas of the rotating electric machine 100 that require cooling to be appropriately cooled.

[0031] As shown in the plan cross-sectional view of Figure 10, multiple power receiving coils 16 may be arranged side by side at the end of the rotor 10 along the circumferential direction of the rotation axis of the rotor 10. Figure 10 shows an example in which five power receiving coils 16 are arranged side by side in two locations. In this case, too, it is preferable that all power receiving coils 16 are arranged in positions along the radial direction of the rotor 10 so as not to overlap with the injection holes 18.

[0032] By arranging a plurality of power receiving coils 16 side by side, the amount of power supplied to the measuring device 102 can be increased, and power can be supplied to the measuring device 102 stably and sufficiently.

[0033] Furthermore, the power receiving coil 16 may be formed in an arc shape along the circumferential direction of the rotation axis of the rotor 10, as shown in the plan cross-sectional view of Fig. 11. Fig. 11 shows an example in which two power receiving coils 16 are arranged. In this case, too, it is preferable that all power receiving coils 16 are arranged in positions along the radial direction of the rotor 10 so as not to overlap with the injection holes 18.

[0034] By extending the power receiving coil 16 in an arc shape along the circumferential direction of the rotation axis of the rotor 10, the area interlinked with the magnetic flux generated by the power transmitting coil 24 increases, and it is possible to increase the induced power generated in the power receiving coil 16. As a result, it is possible to increase the amount of power supplied to the measuring device 102, and it is possible to supply power to the measuring device 102 stably and sufficiently.

[0035] [Configuration of the present invention] [Configuration 1] A rotating electric machine that rotates a rotor, a measuring device provided on the rotor for measuring and outputting a state of the rotor; a power receiving coil provided on the rotor and supplying power to the measuring device; a power transmission coil wound in an annular shape around the circumferential direction of the rotation axis of the rotor and configured to supply power to the power receiving coil in a non-contact manner; Equipped with A jet hole is provided for supplying cooling oil to the shaft of the rotor, The rotating electric machine according to claim 1, wherein the power receiving coil is disposed in a radial direction of the rotor at a position not overlapping with the injection holes. [Configuration 2] The rotating electric machine according to configuration 1, The rotating electric machine is characterized in that the power receiving coil has an arc shape along the circumferential direction of the rotation axis of the rotor. [Configuration 3] The rotating electric machine according to configuration 1, The rotating electric machine is characterized in that a plurality of the power receiving coils are arranged in a line along the circumferential direction of the rotation axis of the rotor. [Configuration 4] A rotating electric machine according to any one of configurations 1 to 3, The rotating electric machine is characterized in that the power receiving coil is provided with a magnetic shield layer on the opposite side to the power transmitting coil. [Explanation of symbols]

[0036] 10 rotor, 10a end plate, 12 rotor shaft, 14 stator, 16 receiving coil, 18 injection hole, 20 bearing, 22 housing case, 24 transmitting coil, 26 magnetic shield, 30 sensor, 32 measuring instrument, 34 output device, 36 armature coil, 36a coil end, 38 current controller, 100 rotating electric machine, 102 measuring device, 104 power supply unit.

Claims

1. A rotating electric machine that rotates a rotor, a measuring device provided on the rotor for measuring and outputting a state of the rotor; a power receiving coil provided on the rotor and supplying power to the measuring device; a power transmission coil wound in an annular shape around the circumferential direction of the rotation axis of the rotor and configured to supply power to the power receiving coil in a non-contact manner; Equipped with A jet hole is provided for supplying cooling oil to the shaft of the rotor, The rotating electric machine according to claim 1, wherein the power receiving coil is disposed in a radial direction of the rotor at a position not overlapping with the injection holes.

2. 2. The rotating electric machine according to claim 1, The rotating electric machine is characterized in that the power receiving coil has an arc shape along the circumferential direction of the rotation axis of the rotor.

3. 2. The rotating electric machine according to claim 1, The rotating electric machine is characterized in that a plurality of the power receiving coils are arranged in a line along the circumferential direction of the rotation axis of the rotor.

4. A rotating electric machine according to any one of claims 1 to 3, The rotating electric machine is characterized in that the power receiving coil is provided with a magnetic shield layer on the opposite side to the power transmitting coil.

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