Rotating electric machine

Abstract

A rotating electric machine in which control is applied to the drive of the rotating electric machine by spraying a refrigerant in the form of a mist towards the heat-generating part of the rotating electric machine, which is located in a closed space of the rotating electric machine. [Solution] A rotating electric machine comprising: a temperature detection unit that detects the temperature of a heat-generating part of the rotating electric machine located in a closed space of the rotating electric machine; a plurality of spray units that spray a cooling fluid in a mist-like form from a plurality of different positions toward the heat-generating part; a steam recovery pipe having an opening in the space and extending from the space toward the outside of the rotating electric machine; and a spray control unit that controls the start and stop of spraying the cooling fluid by the spray units.

Description

Technical Field

[0001] This invention relates to a rotating electric machine, and particularly to a rotating electric machine in which control over the driving of the rotating electric machine is applied by spraying and supplying a refrigerant toward a heat generating portion of the rotating electric machine disposed within a closed space of the rotating electric machine.

Background Art

[0002] The inventor of the present application has proposed applying control over the driving of a rotating electric machine by supplying a refrigerant liquid toward a heat generating portion in the rotating electric machine (Patent Document 1).

[0003] The rotating electric machine disclosed in Patent Document 1 supplies a refrigerant liquid to a gap formed between an ironless cylindrical coil that generates heat when energized and a rotor, vaporizes the refrigerant liquid with the heat generating coil, and controls the temperature of the coil with the latent heat of vaporization of the refrigerant liquid.

[0004] The temperature of an ironless cylindrical coil that generates heat when energized is detected by a coil temperature detection sensor, the supply amount of the refrigerant liquid is adjusted so that the coil does not exceed the allowable upper limit temperature tM, and the supply and stop of the refrigerant liquid to the gap are repeated so that the temperature of the coil that decreases by supplying the refrigerant liquid does not fall below at least the lower limit temperature tN at which the refrigerant liquid vaporizes, thereby maintaining the coil within the range of the allowable upper limit temperature tM and the lower limit temperature tN.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

[0006] The present invention aims to propose a rotating electric machine in which control is applied to the driving of the rotating electric machine by spraying a refrigerant in the form of a mist towards the heat-generating part of the rotating electric machine, which is located within a closed space of the rotating electric machine. [Means for solving the problem]

[0007] The present invention can be illustrated as follows: [1] A temperature detection unit that detects the temperature of the heat-generating part of the rotating electric machine, which is located in the enclosed space of the rotating electric machine, Multiple spraying mechanisms that spray cooling fluid in a mist-like form from multiple different positions toward the heat-generating section, A steam recovery pipe having an opening in the aforementioned space and extending from the aforementioned space toward the outside of the rotating electric machine, A spray control unit controls the start and stop of spraying the cooling fluid by the spray mechanism. A rotating electric machine equipped with this feature.

[0008] [2] The heating element, which is sprayed with the cooling fluid by the spraying mechanism, is a coil in a coreless motor or a slotless motor [1], a rotating electric machine.

[0009] [3] A rotating electric machine having an annular coil, with a plurality of the spraying mechanisms arranged toward the annular coil at predetermined intervals between them in the circumferential direction.[2]

[0010] [4] The heating element is an annular coil fixedly positioned in the space, The annular coil is provided with an inner yoke and an outer yoke, each having a plurality of magnets on the inner and outer surfaces facing the coil in the radial direction, and a rotor is arranged in the space that rotates in the circumferential direction of the coil. A rotating electric machine in which multiple spraying mechanisms spray from the inner yoke toward the inner surface of the annular coil [1].

[0011] [5] The multiple magnets arranged on the circumferential surface of the inner yoke are arranged with an inner yoke outer circumferential groove, which is a groove extending in the direction of the rotor's rotation center, interposed between them in the circumferential direction. The spray mechanism is a rotating electric machine having a plurality of through holes that penetrate the inner yoke radially and face the outer groove of the inner yoke [4].

[0012] [6] The inner yoke and the outer yoke are connected at one end in the direction of the rotor's rotation center by an annular connecting wall that extends circumferentially around the rotor's rotation center and connects them radially. An annular, wing-shaped member extending in the circumferential direction with respect to the rotor's rotation center is provided on the surface of the connecting wall facing the coil. A rotating electric machine in which the vane-shaped member rotates in conjunction with the rotation of the rotor, thereby performing a centrifugal pump function that causes the spray from the inner yoke toward the inner circumferential surface of the coil to flow from the space between the inner yoke and the coil toward the space between the coil and the outer yoke [4] or [5].

[0013] [7] The spray mechanism is equipped with a function to prevent gas from entering the spray mechanism from the space after spraying has stopped [1] or [4] a rotating electric machine.

[0014] [8] The control by the spray control unit is, When the detected temperature detected by the temperature detection unit reaches the spray ON set temperature, the spraying by each spraying unit is started. Regarding the stop of spraying, The spraying from each spraying unit is stopped immediately after spraying. When the detected temperature reaches the spray OFF set temperature, the spraying from each spraying unit is stopped, or The spraying from each spraying unit is stopped when the spraying amount of the cooling fluid from each spraying unit reaches a predetermined spraying amount. is based on any one of them, the rotating electric machine of [1] or [4].

[0015] [9] When the detected temperature detected by the temperature detection unit reaches the spray ON set temperature, the spraying by each spraying unit is started. When the detected temperature reaches the spray OFF set temperature, the spraying from each spraying unit is stopped. In the control by the spray control unit, control is performed to adjust the spraying amount according to the temperature rise per unit time from the time when the detected temperature that has decreased after the start of spraying turns to an increase. The rotating electric machine of [8].

[0016]

[10] When the detected temperature detected by the temperature detection unit reaches the spray ON set temperature, the spraying by each spraying unit is started. When the detected temperature reaches the spray OFF set temperature, the spraying from each spraying unit is stopped. In the control by the spray control unit, the spraying amount from the spraying unit is adjusted, and control is performed to change the spray ON set temperature and the spray OFF set temperature. The rotating electric machine of [8].

[0017]

[11] When the detected temperature detected by the temperature detection unit reaches the spray ON set temperature, the spraying by each spraying unit is started. When the spraying amount of the cooling fluid from each spraying unit reaches a predetermined spraying amount, the spraying from each spraying unit is stopped. In the control by the spray control unit, the spraying amount is calculated from the heat capacity of the heat generating unit and the heat of vaporization of the cooling fluid. The rotating electric machine of [8].

Advantages of the Invention

[0018] According to this invention, it is possible to provide a rotating electric machine in which control is applied to the driving of the rotating electric machine by spraying a refrigerant in the form of a mist towards the heat-generating part of the rotating electric machine which is located in a closed space of the rotating electric machine.

[0019] The rotating electric machine of the present invention can be used in various devices and equipment that have a rotating part, such as a wheel, as a drive unit, which rotates circumferentially around a centrally extending shaft. For example, it can be used in the drive wheels of a four-wheeled automobile or a mobile robot, or in the rotating parts of a robot. [Brief explanation of the drawing]

[0020] [Figure 1] A perspective view illustrating the structure of a rotating electric machine according to one embodiment of the present invention, with parts cut out and parts omitted. [Figure 2] A perspective view illustrating the structure of a rotating electric machine according to another embodiment of the present invention, with parts cut out and parts omitted. [Figure 3] A perspective view illustrating an example of an annular coil in a rotating electric machine according to one embodiment of the present invention. [Figure 4] Figure 3 shows an enlarged view of one configuration of the wire input and output ends of the bundled wires at the input and output ends of the coil, respectively. [Figure 5] A diagram illustrating the schematic configuration of an example of a control system for controlling the drive of a rotating electric machine and spraying by a spraying mechanism according to one embodiment of the present invention. [Figure 6] (a), (b), and (c) are conceptual diagrams illustrating examples of methods for liquefying steam recovered through steam recovery pipes. [Figure 7] A conceptual diagram illustrating an example of a mechanism for draining water accumulated in the enclosed space of a rotating electric machine. [Figure 8] (a), (b), (c), and (d) are diagrams illustrating various examples of configurations in which the rotating electric machine of the present invention is used as an in-wheel motor in an automobile. [Figure 9] A conceptual diagram illustrating an example of the arrangement position of spray nozzles when the rotating electric machine of the present invention is a core motor. [Figure 10] (a) and (b) are conceptual diagrams illustrating an example of the arrangement position of the spray nozzle when the rotating electric machine of the present invention is a core motor. [Figure 11] (a) is a conceptual diagram illustrating an example where the rotating electric machine of the present invention is a flat motor (face-facing motor), (b) is a diagram showing the schematic configuration of the magnet facing the magnet yoke in the flat motor shown in Figure 11(a), and (c) is a diagram showing the schematic configuration of the magnet yoke facing the magnet in the flat motor shown in Figure 11(a). [Figure 12] This graph shows experimental data relating the spray from the spray mechanism according to Embodiment 1 of the spray mechanism, which is adopted as one embodiment of the present invention in the rotating electric machine shown in Figure 1, to the temperature of the heat-generating part (the coil part of the rotating electric machine). [Figure 13] This figure illustrates an example of a spray mechanism according to Embodiment 2 of a spray mechanism adopted as one embodiment of the present invention, wherein (a) is a partially omitted cross-sectional view illustrating one embodiment of a through hole formed radially in the inner yoke, and (b) is a partially omitted diagram showing an example of the opening position of a through hole facing the outer groove of the inner yoke between a plurality of magnets arranged on the radial outer surface of the inner yoke. [Figure 14] (a) and (b) are diagrams that partially omit the state in which the inner grooves of the outer yoke between multiple magnets arranged on the radial inner surface of the outer yoke are filled with a filler material, as shown in the structure illustrated in Figure 13. [Figure 15] (a) is a cross-sectional view showing a part of the spray mechanism described in Figure 13, with some details omitted, and (b) is a cross-sectional view showing another embodiment of the spray mechanism shown in Figure 15(a), with some details omitted. [Figure 16] (a) and (b) are cross-sectional views showing other embodiments of the spray mechanism illustrated in Figures 15(a) and (b), with parts omitted to illustrate them. [Figure 17]Figures 15(b) and 16(b) illustrate an example of an annular wing-shaped member used in the embodiment shown, where (a) is a perspective view, (b) is a diagram showing a part of Figure 17(a) with some parts omitted and some parts enlarged, and (c) is a diagram showing a part of Figure 17(b) with some parts omitted and some parts enlarged. [Modes for carrying out the invention]

[0021] <An embodiment of a rotating electric machine> Figure 1 illustrates an example in which a rotating electric machine 1a according to one embodiment of the present invention is configured as a coreless motor, in which an annular casing 11 rotates in the circumferential direction of the fixed shaft 10a around the fixed shaft 10a.

[0022] In the illustrated embodiment, the casing 11 constituting the rotating electric machine 1a is supported on the fixed shaft 10a via bearings 52a and 52b, so as to be able to rotate freely in the circumferential direction of the fixed shaft 10a with respect to the fixed shaft 10a.

[0023] The rotating electric machine 1a has its internal space closed by an annular portion 11a that constitutes the casing 11, a circular one-side end plate 12a that constitutes the rotor 9 at one end of the annular portion 11a in the axial direction of the fixed shaft 10a, and a circular cover plate 51 that closes the other end of the annular portion 11a in the axial direction of the fixed shaft 10a.

[0024] An annular coil 7, with the fixed shaft 10a as its radial center, is supported by the fixed shaft 10a. In Figure 1, reference numerals 60 and 61 indicate a spacer and a brake mounting part, respectively.

[0025] As the annular coil 7, which is arranged concentrically with respect to the axis that is the center of the rotational motion of the rotor in a rotating electric machine, various annular coils known in this art can be used.

[0026] Conventionally, coreless motors, or slotless motors (though not shown), have employed annular coils, and the applicant of this application has also proposed annular coils, as shown in Figures 3 and 4, in Patent Document 2.

[0027] For the coreless motor, the rotating electric machine 1a can employ an annular coil 7, as an example of a conventionally known annular coil, as disclosed in Patent Document 2, shown in Figures 3 and 4.

[0028] The entirety of the disclosure in Patent Document 2 (Japanese Patent No. 7594796) is incorporated herein by reference.

[0029] The coil 7 shown in Figures 3 and 4, which is an annular coil disclosed in Patent Document 2, is composed of a U-phase coil 30, a V-phase coil 31, and a W-phase coil 32, and is an annular coil having three phases: U-phase, V-phase, and W-phase.

[0030] The annular coil 7 shown in Figure 3 is arranged concentrically with respect to the axis of rotation of the rotating electric machine, indicated by the dashed line 100 in Figure 3, and surrounds the axis 100 in a circumferential direction relative to the axis 100. The coil 7 has multiple phases. In Figures 3 and 4, the annular coil 7 consists of three phases: U phase, V phase, and W phase.

[0031] The annular coil 7 is composed of multiple phase coils, each of which constitutes one of the multiple phases, and each of these phase coils has a phase coil input terminal and a phase coil output terminal.

[0032] In Figures 3 and 4, the annular coil 7 is a three-phase coil consisting of U-phase, V-phase, and W-phase, and is composed of a U-phase coil 30, a V-phase coil 31, and a W-phase coil 32. The U-phase coil 30 is a phase coil having a U-phase coil input terminal U21 at one end and a U-phase coil output terminal U22 at the other end. The V-phase coil 31 is a phase coil having a V-phase coil input terminal V31 at one end and a V-phase coil output terminal V32 at the other end. The W-phase coil 32 is a phase coil having a W-phase coil input terminal W41 at one end and a W-phase coil output terminal W42 at the other end (Figure 3).

[0033] Multiple such phase coils are arranged such that, as shown in Figure 3, each phase coil is offset from the other in the circumferential direction relative to the axial direction 100, thereby forming an annular coil 7. In Figure 3, the V-phase coil 31 is offset from the U-phase coil 30 in the circumferential direction, and the W-phase coil 32 is offset from the V-phase coil 31 in the circumferential direction.

[0034] In the embodiments shown in Figures 3 and 4, the U-phase coil 30, V-phase coil 31, and W-phase coil 32 are all constructed by bundling together six long conductive wires, and have the same configuration and structure. Therefore, the U-phase coil 30 will be described below, and the descriptions of the V-phase coil 31 and W-phase coil 32 will be omitted.

[0035] The U-phase coil 30 is composed of six long conductive wires U5-1, U5-2, U5-3, U5-4, U5-5, and U5-6 bundled together (Figure 4).

[0036] Wire U5-1 has a wire input terminal U5-1-1 and a wire output terminal U5-1-2, extending from the wire input terminal U5-1-1 to the wire output terminal U5-1-2. Wire U5-2 has a wire input terminal U5-2-1 and a wire output terminal U5-2-2, extending from the wire input terminal U5-2-1 to the wire output terminal U5-2-2. Wire U5-3 has a wire input terminal U5-3-1 and a wire output terminal U5-3-2, extending from the wire input terminal U5-3-1 to the wire output terminal U5-3-2. Wire U5-4 has a wire input terminal U5-4-1 and a wire output terminal U5-4-2, extending from the wire input terminal U5-4-1 to the wire output terminal U5-4-2. Wire U5-5 has a wire input terminal U5-5-1 and a wire output terminal U5-5-2, extending from the wire input terminal U5-5-1 to the wire output terminal U5-5-2. Wire U5-6 has a wire input terminal U5-6-1 and a wire output terminal U5-6-2, extending from the wire input terminal U5-6-1 to the wire output terminal U5-6-2 (Figure 4).

[0037] As shown in Figure 4, the input terminals U5-1-1, U5-2-1, U5-3-1, U5-4-1, U5-5-1, and U5-6-1 of wires U5-1, U5-2, U5-3, U5-4, U5-5-1, and U5-6-1 are all located at the U-phase coil input terminal U21, which is the input terminal of the phase coil.

[0038] Furthermore, the wire output terminals U5-1-2, U5-2-2, U5-3-2, U5-4-2, U5-5-2, and U5-6-2 of wires U5-1, U5-2, U5-3, U5-4-2, U5-5-2, and U5-6-2 are all located at the U-phase coil output terminal U22, which is the phase coil output terminal.

[0039] Thus, each wire has wire input terminals U5-1-1, U5-2-1, U5-3-1, U5-4-1, U5-5-1, and U5-6-1, and wire output terminals U5-1-2, U5-2-2, U5-3-2, U5-4-2, U5-5-2, and U5-6-2, and the wire input terminals U5-1-1, U5-2-1, and U5-6-2 are located at the U-phase coil input terminal U21, which is the input terminal of the phase coil. Six long conductive wires U5-1, U5-2, U5-3, U5-4, U5-5, and U5-6, which extend from U5-3-1, wire input terminal U5-4-1, wire input terminal U5-5-1, and wire input terminal U5-6-1 to wire output terminal U5-1-2, wire output terminal U5-2-2, wire output terminal U5-3-2, wire output terminal U5-4-2, wire output terminal U5-5-2, and wire output terminal U5-6-2 located at the U-phase coil output terminal U22, which is the phase coil output terminal, are bundled together to form the U-phase coil 30 as a phase coil.

[0040] The long conductive wires U5-1, U5-2, U5-3, U5-4, U5-5, and U5-6 are, for example, made of copper, and are extremely fine wires with their outer circumference covered with an enamel layer or the like. The wire diameter is selected from, for example, a range of 0.05 to 0.2 mm. The bundle of six wires U5-1, U5-2, U5-3, U5-4, U5-5, and U5-6 is covered with a fibrous material made of glass fiber or the like.

[0041] Since multiple long conductive wires are bundled together in this manner, each phase coil is also long. The U-phase coil 30 is a long phase coil extending from the U-phase coil input terminal U21 at one end to the U-phase coil output terminal U22 at the other end. The V-phase coil 31 is a long phase coil extending from the V-phase coil input terminal V31 at one end to the V-phase coil output terminal V32 at the other end. The W-phase coil 32 is a long phase coil extending from the W-phase coil input terminal W41 at one end to the W-phase coil output terminal W42 at the other end.

[0042] As shown in Figure 3, in an annular coil 7 in which the V-phase coil 31 is positioned offset circumferentially from the U-phase coil 30, and the W-phase coil 32 is positioned offset circumferentially from the V-phase coil 31, the long U-phase coil 30, the long V-phase coil 31, and the long W-phase coil 31 each extend circumferentially while repeatedly curving up and down in a wave-like manner in the axial direction 100, as shown in Figure 3.

[0043] In other words, in each of the U-phase coil 30, V-phase coil 31, and W-phase coil 32, the U-phase coil input terminal U21 and the U-phase coil output terminal U22 are located in close proximity in the circumferential direction, the V-phase coil input terminal V31 and the V-phase coil output terminal V32 are located in close proximity in the circumferential direction, and the W-phase coil input terminal W41 and the W-phase coil output terminal W42 are located in close proximity in the circumferential direction. Furthermore, the long U-phase coil 30, the long V-phase coil 31, and the long W-phase coil 32 each extend in the circumferential direction while repeatedly curving in a wave-like manner up and down in the axial direction 100, as shown in Figure 3, so that the entirety of the U-phase coil input terminal U21, the U-phase coil output terminal U22, the V-phase coil input terminal V31, the V-phase coil output terminal V32, the W-phase coil input terminal W41, and the W-phase coil output terminal W42 are located in close proximity in the circumferential direction.

[0044] In the embodiment shown in Figure 1, power lines 17a, 17b, and 17c are drawn out corresponding to the three phases U, V, and W.

[0045] An annular coil 7 is sandwiched radially between the fixed shaft 10a, and the inner yoke 5 and outer yoke 6 are arranged concentrically with respect to the fixed shaft 10a. In the illustrated embodiment, an inner magnet 15a is provided on the radially outer surface of the inner yoke 5, and outer magnets 16a, 16b, and 16c are provided on the radially inner surface of the outer yoke 6.

[0046] As a result, the annular inner magnet 15a and the annular outer magnets 16a, 16b, and 16c are arranged in a concentric circle around the fixed axis 10a, with the annular coil 7 sandwiched radially between them.

[0047] In the illustrated embodiment, the side of the rotor 9 opposite to the one end plate 12a is composed of a circular other end plate 12b, and the inner yoke 5 and outer yoke 6 are supported by the one end plate 12a and the other end plate 12b, respectively.

[0048] Furthermore, the other end plate 12b that constitutes the rotor 9 is rotatably supported on the fixed shaft 10a via bearings 52a, 52b, a member 53 that supports bearings 52a, 52b, and an oil seal 54.

[0049] This structure allows the casing 11 to be rotatably supported on the fixed shaft 10a via bearings 52a and 52b.

[0050] With a magnetic field formed between the inner magnet 15a and the outer magnets 16a, 16b, and 16c, energizing the coil 7 causes the rotor 9, which is equipped with an inner yoke 5 and an outer yoke 6, to rotate around the fixed shaft 10a in the circumferential direction of the fixed shaft 10a, thereby causing the casing 11 to rotate around the fixed shaft 10a in the circumferential direction of the fixed shaft 10a.

[0051] Figure 2 illustrates an example in which a rotating electric machine 1b according to one embodiment of the present invention is configured as a coreless motor, similar to the embodiment shown in Figure 1. In the embodiment shown in Figure 2, unlike the embodiment shown in Figure 1, the annular casing 11 rotates in the circumferential direction of the rotating shaft 10b around the rotating shaft 10b.

[0052] The internal space of the rotating electric machine 1b is closed off by the annular portion 11b that constitutes the casing 11, the circular one-side end plate 12a that closes one end of the annular portion 11b in the axial direction of the rotating shaft 10b, and the circular other-side end plate 12b that closes the other end of the annular portion 11b in the axial direction of the rotating shaft 10b.

[0053] Since the casing 11 rotates in the circumferential direction of the rotating shaft 10b around the rotating shaft 10b, one end plate 12a and the other end plate 12b are supported by the rotating shaft 10b so as to be able to rotate freely via bearings 52c and 52d, respectively. In addition, a rotational motion transmission mechanism consisting of multiple gears, such as a gear 14, is arranged inside the casing 11 to transmit the rotational motion of the rotor 9 to the rotational motion of the casing 11.

[0054] Although not shown in the illustration, a rotational motion transmission mechanism consisting of multiple gears, which is arranged inside the casing 11 and transmits the rotational motion of the rotor 9 to the rotational motion of the casing 11, can be adopted from the mechanisms disclosed in Patent Documents 3, 4, etc.

[0055] Furthermore, the entirety of the disclosures in Patent Document 3 (Japanese Patent No. 6278432) and Patent Document 4 (Japanese Patent No. 6589215) are incorporated herein by reference.

[0056] As described above, the rotating electric machine 1a in the embodiment shown in Figure 1 and the rotating electric machine 1b in the embodiment shown in Figure 2 differ in that the center of rotational motion of the casing 11 in the circumferential direction is either a fixed shaft 10a or a rotating shaft 10b, but the structure and mechanism related to the present invention are common. Therefore, in the rotating electric machine 1b of Figure 2, the same reference numerals used in the description of the rotating electric machine 1a of Figure 1 are used for parts that are common with the rotating electric machine 1a of Figure 1, and their description is omitted.

[0057] Furthermore, the following explanation will focus on the rotating electric machine 1a shown in Figure 1, describing the structure and mechanism of the present invention related to the rotating electric machine 1a, but this explanation is also applicable to the rotating electric machine 1b shown in Figure 2.

[0058] <Spray Mechanism Embodiment 1> In the rotating electric machines 1a and 1b of the embodiment shown in Figures 1 and 2, a temperature sensor 8 for detecting the temperature of the coil 7, which is a heat-generating part of the rotating electric machines 1a and 1b, is positioned near the coil 7. Note that the position where the temperature sensor 8 is attached is not limited to the position shown in Figures 1 and 2, but can also be at the connection point between the coil 7 and the conductor (power line) connected to the coil 7, etc. When the rotating electric machines 1a and 1b are driven, these areas also generate heat in the same way as the coil 7. Therefore, from the viewpoint of suppressing the increase in resistance due to the temperature rise of the coil 7, the temperature sensor 8 can be placed not only near the coil 7, but also near other heat-generating parts that experience a temperature rise in the same way as the coil 7 during operation, such as the connection point between the coil 7 and the conductor (power line) connected to the coil 7.

[0059] The temperature detected by the temperature sensor 8, which can be made up of a thermistor or the like, is output to the controller 21 (Figure 5), which constitutes the control unit, via the signal line 17d.

[0060] The rotating electric machines 1a and 1b are equipped with a spray mechanism that sprays a cooling fluid in a mist-like form from multiple different positions toward the heat-generating parts of the rotating electric machines 1a and 1b.

[0061] In the illustrated embodiment, the rotating electric machines 1a and 1b are coreless motors, and the annular coil 7 shown in Figures 3 and 4 is the main heat-generating part when the rotating electric machines 1a and 1b are driven. Therefore, a cooling fluid is sprayed in a mist-like manner from multiple different positions toward the annular coil 7, which is the heat-generating part of the rotating electric machines 1a and 1b.

[0062] It is desirable that the cooling fluid be sprayed in a mist from multiple different positions so that the cooling fluid is uniformly and widely sprayed in a mist form toward the annular coil 7, which is the main heat-generating part.

[0063] In the embodiment shown in Figure 1, multiple spray nozzles 3a, ..., 3e, 3f, etc. are arranged around a fixed shaft 10a, with predetermined intervals between them in the circumferential direction of the fixed shaft 10a to form a spray mechanism. In the embodiment shown in Figure 2, multiple spray nozzles 3a, etc. are arranged around a rotating shaft 10b, with predetermined intervals between them in the circumferential direction of the rotating shaft 10b to form a spray mechanism.

[0064] The cooling fluid supplied via the water supply pipe 4 is sprayed in a mist-like manner towards the annular coils 7, which are the heat-generating parts of the rotating electric machines 1a and 1b, via multiple spray nozzles 3a, etc.

[0065] If metal such as copper pipes is present between the heat-generating part and the spraying part of the rotating electric machines 1a and 1b, the cooling of the heat-generating part by the mist-like spraying of the cooling fluid becomes indirect. In this case, the thermal conductivity of the intervening metal (e.g., copper) interferes, suppressing the cooling efficiency (cooling rate).

[0066] In this embodiment, the cooling fluid supplied via the water supply pipe 4 is sprayed in a mist-like manner from multiple spray nozzles 3a, etc., toward the annular coils 7, which are the heat-generating parts of the rotating electric machines 1a and 1b, thereby increasing the cooling efficiency (cooling rate).

[0067] In the case where the heating element of the rotating electric machines 1a and 1b is the annular coil 7 shown in the figure, multiple spray nozzles 3a, etc., are arranged around the fixed shaft 10a and the rotating shaft 10b, with a predetermined spacing between them in the circumferential direction of the fixed shaft 10a and the rotating shaft 10b, thus enabling a mist-like spray flow to spread around the entire circumference of the annular coil 7, which is the main heating element.

[0068] In the illustrated embodiment, the mist-like spraying of cooling fluid towards the heat-generating parts of the rotating electric machines 1a and 1b via multiple spray nozzles 3a, etc., is directed to the space between the radially inner surface of the annular coil 7, which is the main heat-generating part, and the radially outer surface of the inner magnet 15, or the space between the radially outer surface of the annular coil 7, which is the main heat-generating part, and the radially inner surfaces of the outer magnets 16a, 16b, and 16c, or both of these spaces.

[0069] The distance between these spaces in the radial direction, centered on the fixed axis 10a and the rotating axis 10b, is, for example, about 1 mm.

[0070] Thus, although the radial distance between the annular coil 7 and the inner magnet 15a and outer magnets 16a, 16b, and 16c is narrow, when the coil 7 is energized, the rotor 9, which is equipped with an inner yoke 5 and an outer yoke 6, rotates at high speed in the circumferential direction around the fixed shaft 10a and the rotating shaft 10b. This allows a mist-like spray flow to quickly spread throughout the entire annular coil 7.

[0071] Simply bringing the cooling fluid into contact with the coil 7, which is the main heat-generating part, in the form of liquid droplets may result in the area over which the droplets act being limited.

[0072] In contrast, in the rotating electric machines 1a and 1b of this embodiment, a mist-like spray of cooling fluid is produced from each of the multiple spray nozzles 3a, etc., that constitute the spray mechanism. That is, by adjusting the size of the spray opening, spray pressure, spray volume, etc., the spray of the cooling fluid from each of the multiple spray nozzles 3a that constitute the spray mechanism becomes a fine mist, or fine atomized spray. As a result, the mist-like spray is evenly distributed over a wide area of ​​the heating surface of the coil 7, which is the main heat-generating part. Moreover, the rotational force of the rotating body (magnet, magnet yoke, etc.) facing the coil 7 causes the fine mist-like spray to spread even more evenly over the entire surface of the coil 7.

[0073] The cooling fluid, which is in mist form, is sprayed not only onto the coil and magnet, but also onto the wire connecting the power line and the coil, as mentioned above, as this also generates heat similarly to the coil and therefore becomes a target for the spray.

[0074] Copper is typically used for coil 7 and the wires connected to it.

[0075] In this case, the resistance of copper changes significantly with temperature. For example, if the resistance at 0°C is 234.5Ω, then the resistance at A°C will be (234.5 + A)Ω, and if the resistance coefficient at 0°C is 234.5, then the resistance at A°C will be (234.5 + A).

[0076] Therefore, when the temperature rises from 20°C to 100°C, the resistance becomes (234.5 + 100) Ω / (234.5 + 20) Ω = 1.31 times.

[0077] When the temperature drops from, for example, 120°C to 60°C due to the simultaneous mist-like spraying of the cooling fluid from multiple points as described above, the resistance value becomes 83.1%. This also means that if the pressure is reduced from 1 atmosphere of vaporization cooling at 120°C to 0.2 atmospheres, and the boiling point is lowered to 60°C, the resistance value will also become 83.1%.

[0078] Thus, the cooling effect of simultaneously spraying a cooling fluid in a mist-like form onto the heating element, which consists of a copper coil 7, from multiple locations has a tremendous impact on the resistance value.

[0079] When the cooling fluid is water, there is a constraint that the main heat-generating parts, such as the coil 7, must be above 100°C. However, it is important to directly and instantaneously remove 2257 J of heat as latent heat of vaporization with just 1 gram of water. In this embodiment, heat can be instantly removed by utilizing latent heat of vaporization, simultaneously and with a small amount of spray, directed towards multiple locations on the main heat-generating parts, the coil 7.

[0080] It is advantageous for each of the above-described spraying mechanisms to be configured to have a function that prevents gas from entering the spraying mechanism from the space after spraying has stopped. In other words, in the above-described embodiment, it is advantageous for each of the spraying nozzles 3a, etc. that constitute the spraying mechanism to be configured to have a function that prevents gas from entering the spraying nozzles 3a, etc. from the space after spraying has stopped. Hereinafter in this specification, the "function that prevents gas from entering the spraying nozzles 3a, etc. from the closed space covered by the casing 11 around the fixed shaft 10a or the rotating shaft 10b after spraying has started from the spraying nozzles 3a, etc." may simply be referred to as the "intrusion prevention function".

[0081] After spraying begins from the spray nozzle 3a, etc., if gas in the closed space covered by the casing 11 around the fixed shaft 10a or rotating shaft 10b enters the spray nozzle 3a, etc., the cooling fluid sprayed in a mist-like manner from the spray nozzle 3a, etc. towards the closed space will flow back into the spray nozzle 3a, etc., and there is a risk of clogging of the spray nozzle 3a, etc.

[0082] The intrusion prevention function described above can prevent such malfunctions from occurring in the first place.

[0083] As a measure to prevent intrusion as described above, for example, the spray from the spray nozzle can be made instantaneous, and the spray can be stopped immediately after it starts, thereby preventing any time from giving gas a chance to enter the spray nozzle 3a, etc., from within the closed space.

[0084] Furthermore, the spray nozzles 3a, etc., can be configured to have the above-mentioned intrusion prevention function realized by each being equipped with a check valve 13a, 13b, ~, 13e, 13f, 13g (Figure 1).

[0085] As will be described later, the water supply source (container) containing the cooling fluid may be positioned higher vertically than the rotating electric machine 1a. However, by employing a spray nozzle equipped with a check valve, even in such cases, it is possible to prevent the cooling fluid from leaking out of the spray nozzle due to the difference in height.

[0086] In the rotating electric machines 1a and 1b of this embodiment, as described above, the cooling fluid is sprayed directly in a mist form onto the coils 7, which are the main heat-generating parts of the rotating electric machines 1a and 1b. This improves the cooling efficiency.

[0087] According to simulations of the structure of the rotating electric machines 1a and 1b in this embodiment, if six spray units are arranged at predetermined intervals in the circumferential direction, as in this embodiment, and 1 mL (milliliters) of water is sprayed as a mist from each spray unit at a time, the temperature of the coil 7 will drop by 8.3 K. Therefore, when the detection temperature of the coil 7, which is the main heat-generating part, reaches the spray ON setting temperature of 120 °C, if 1 mL (milliliters) of water is sprayed as a mist from all six spray units simultaneously, the temperature of the coil 7 will drop to 111.7 °C, and all the sprayed water will evaporate. Thus, when performing simultaneous spraying from multiple spray units, the amount sprayed from each spray unit can be set to the amount that evaporates immediately after spraying, for example, 1 mL (milliliters) of water.

[0088] As described above, the distance between the radially inner surface of the annular coil 7 and the radially outer surface of the inner magnet 15, and the distance between the radially outer surface of the annular coil 7 and the radially inner surfaces of the outer magnets 16a, 16b, and 16c are approximately 1 mm.

[0089] As described above, when performing simultaneous mist spraying from multiple spray nozzles, setting the amount sprayed from each spray unit to the amount that evaporates immediately after spraying, for example, 1 mL (milliliters) if the cooling fluid is water, ensures that the rotation of the rotor 9 is not hindered even when spraying into such narrow gaps.

[0090] Furthermore, the cooling fluid, which is sprayed in a mist-like form from the spray nozzle and contributes to the evaporative cooling of the heat-generating coil 7, immediately evaporates as described above, and its volume increases by approximately 1000 times.

[0091] The rotating electric machines 1a and 1b of this embodiment have an opening (not shown) in an internal space that is closed by a cylindrical portion 11a constituting the casing 11, a circular one-sided end plate 12a, and a circular cover plate 51, and can be configured to have a steam recovery pipe 18 (Figure 1) extending from this internal space toward the outside of the rotating electric machine 1a.

[0092] As described above, the cooling fluid sprayed in mist form from the spray nozzle 3a, etc. toward the heat-generating part is vaporized by the heat-generating part such as the coil 7, and its volume increases by about 1000 times, causing the pressure in the closed internal space of the rotating electric machine 1a to rise.

[0093] As described above, since the steam recovery pipe 18 has an opening (not shown) in the closed internal space of the rotating electric machine 1a, the steam is quickly discharged through the steam recovery pipe 18 from the internal space where the pressure has risen due to vaporization by the heat-generating parts such as the coil 7, which increases in volume.

[0094] By positioning the tip opening of the steam recovery pipe 18, which extends from the closed internal space of the rotating electric machine 1a, towards the internal space of the water tank 50 containing the cooling fluid 40, as shown in Figure 6(a), or within the cooling fluid 40 in the water tank 50, as shown in Figure 6(b), the exhaust gas that has flowed from the closed internal space of the rotating electric machine 1a through the steam recovery pipe 18 can be quickly returned to the cooling fluid 40.

[0095] Furthermore, when the rotating electric machine 1a of this embodiment is used as a wheel-in motor in an electric vehicle, as shown in Figure 6(c), the exhaust can be returned to the cooling fluid 40 by passing through the vent pipe 29 and the vehicle's radiator.

[0096] As described above, the cooling fluid sprayed in mist form from the spray nozzle 3a, etc. toward the heat-generating part is ideally 100% vaporized within the closed internal space of the rotating electric machines 1a and 1b, and then exhausted to the outside via the steam recovery pipe 18.

[0097] It is desirable to spray only the minimum necessary amount of cooling liquid each time it is sprayed. Excessive supply is undesirable because if the cooling liquid returns to a liquid state and remains in the enclosed internal space of the rotating electric machines 1a and 1b, it will create rotational resistance.

[0098] Furthermore, in case of excessive spray volume, or if the cooling fluid has returned to a liquid state within the closed internal spaces of the rotating electric machines 1a and 1b, the following configuration can be adopted.

[0099] If the amount of spray is excessive, and there is cooling fluid that has returned to a liquid state within the closed internal spaces of the rotating electric machines 1a and 1b, the cooling fluid generated within these internal spaces will adhere to the inner surface of the casing 11 due to centrifugal force caused by the rotation of the rotor 9.

[0100] Therefore, as shown in Figure 7, a recess 26 is formed on the inner circumferential surface of the casing 11, which is recessed radially outward. This allows the cooling fluid generated in the closed internal space of the rotating electric machines 1a and 1b to collect here, and a configuration and structure can be adopted to discharge this fluid to the outside.

[0101] Figure 7 is a conceptual diagram illustrating one aspect of this form and structure. A spatula 24 is attached to the radially outer side of the fluid recovery pipe 25, which communicates with the outside of the casing 11, and is inserted into a recess 26 formed on the inner circumferential wall surface of the casing 11, which rotates in the circumferential direction, to recover fluid from the recess 26 into the fluid recovery pipe 25. The spatula 24 is made of a soft material, such as silicone.

[0102] The fluid from the fluid recovery pipe 25 can be recovered, for example, into the water tank 50 described above.

[0103] Furthermore, in the mechanism illustrated in Figure 7, when cooling fluid accumulates in the recess 26, it is possible to create an embodiment in which the amount of water accumulated in the recess 26 can be detected as water volume detection information in the driver's seat of a car equipped with the rotating electric machines 1a and 1b as wheel-in motors.

[0104] Even if the cooling fluid is sprayed in a mist-like manner at six locations inside the annular coil 7, for example, if the control temperature is measured at only one location near the coil, a time lag may occur between the start of spraying and the temperature of the coil 7 decreasing.

[0105] The airflow within the enclosed internal spaces of the rotating electric machines 1a and 1b flows from the radially inner side to the radially outer side of the annular coil 7. Therefore, the mist sprayed from the spraying section toward the coil 7 is structured to circulate from the inner circumference to the outer circumference in the radial direction of the coil 7.

[0106] In this invention, the cooling fluid is sprayed in the form of a mist toward the heat-generating part, as described above. Here, the mist should be as fine as possible, preferably a micro-mist. This is because the mist broadly covers the heat-generating part and is easily vaporized.

[0107] <Embodiment of the spraying mechanism 2> In the above-described embodiment 1 of the spray mechanism, the main heat-generating part of the rotating electric machines 1a and 1b is a fixedly positioned annular coil 7, and the spray mechanism that sprays a cooling fluid in a mist-like manner onto the coil 7 from multiple different positions consists of multiple spray nozzles 3a, etc., arranged in the circumferential direction of the coil 7 at predetermined intervals from each other.

[0108] In contrast, in Embodiment 2 described below, the spraying mechanism sprays a cooling fluid in a mist-like form toward the inner circumferential surface of the annular coil 7 from an inner yoke located radially inward of the annular coil.

[0109] Except for this point, the spray mechanism is the same as described in Embodiment 1 above. Therefore, the same parts will be omitted from the explanation below, and only the characteristic feature of Embodiment 2 of the spray mechanism, which is the mist-like spraying of the cooling fluid from the inner yoke located radially inward of the annular coil toward the inner circumferential surface of the annular coil 7, will be described.

[0110] As described in the above-mentioned "Embodiment of a Rotating Electric Machine," in this second embodiment of the spray mechanism, the main heat-generating part is an annular coil 7 fixedly positioned within a closed space covered by a casing 11 around a fixed shaft 10a or a rotating shaft 10b.

[0111] The rotor 9 is composed of an inner yoke 5 located radially inside the annular coil 7 and an outer yoke 6 located on the outside, and the rotor 9 rotates in the circumferential direction of the coil 7. On the radially outer surface of the inner yoke 5, which is the surface facing the coil 7, inner magnets 15a, 15b, 15c, 15d, 15e, and 15f are arranged in the circumferential direction with predetermined spacing between them. On the radially inner surface of the outer yoke 6, which is the surface facing the coil 7, outer magnets 16a, 16b, 16c, 16d, 16e, and 16f are arranged in the circumferential direction with predetermined spacing between them (Figures 13 and 14). In this specification and drawings, the inner magnets 15a to 15f, etc. are collectively referred to as "inner magnet 15," and the outer magnets 16a to 16f are collectively referred to as "outer magnet 16."

[0112] Furthermore, to prevent the inner magnets 15a, 15b, 15c, 15d, 15e, and 15f from detaching from the radially outer surface of the inner yoke 5 due to the centrifugal force generated by the rotation of the rotor 9 in the circumferential direction of the annular coil 7, the inner magnets 15 can be fixed to the inner yoke 5 by fixing means, such as screws 85a and 85b, as shown in Figures 15 and 16.

[0113] As a spray mechanism that sprays a cooling fluid in a mist-like manner from an inner yoke 5 located radially inside the annular coil 7, the following exemplary configurations can be adopted.

[0114] Multiple inner magnets 15a, 15b, 15c, 15d, 15e, and 15f, which are arranged on the radially outer surface of the inner yoke 5, are arranged with inner yoke outer circumferential grooves 83a, 83b, 83c, 83d, 83e, and 83f, which are grooves extending in the direction of the rotation center of the rotor 9, interposed between them in the circumferential direction, as shown in Figures 13 and 14.

[0115] As shown in Figure 13(a), through holes 91, 92, 93, 94, and 95 are formed in the outer circumferential grooves 83a, 83b, 83c, 83d, 83e, and 83f of the inner yoke, which penetrate the inner yoke 5 in the radial direction.

[0116] The through holes 91, 92, 93, 94, and 95 can be arranged in a row of five (93a-93e, 94a-94e, 95a-95e) in the outer circumferential grooves 83c, 83d, and 83e of the inner yoke between adjacent magnets, as shown in Figure 13(b). Alternatively, multiple rows of holes can be provided in each outer circumferential groove of the inner yoke, or multiple holes can be provided in a staggered pattern.

[0117] In this second embodiment of the spray mechanism, since the cooling fluid is sprayed in a mist form, it is desirable that the diameter of the opening of the through hole facing the outer circumferential groove of the inner yoke be small. For example, the through hole 91, etc., can be made into a small hole with a diameter of 1.5 mm or less, facing the outer circumferential groove 83c of the inner yoke.

[0118] In this embodiment, which will be explained using Figures 13 to 17, the spraying mechanism is configured to include a spray nozzle 3h, which is the spray nozzle described in Embodiment 1 of the spraying mechanism described above, a plurality of through holes 91 to 95 as described above, and a spray passage 81 that connects the spray nozzle 3h and the through holes 91 to 95.

[0119] In other words, in this embodiment, the spray from the spray nozzle 3h, which is the spray nozzle described in Embodiment 1 of the spray mechanism described above, is sprayed in a mist-like manner toward the inner circumferential surface of the coil 7 through the internal space 82 of the spray passage 81 formed in the inner yoke 5 and each through hole 91.

[0120] Figure 16 illustrates an example in which the position where the spray from the nozzle 3h is applied, indicated by arrow 80c, to the spray passage 81 formed within the inner yoke 5 is radially inward compared to the embodiment shown in Figure 15. In this case, as shown in Figure 16, if the spray passage 81 has a structure that includes an upwardly inclined surface 81a and a downwardly inclined surface 81b opposite to it, it is advantageous for spraying the spray from the spray nozzle 3h in a mist-like manner toward the inner circumferential surface of the coil 7 through the internal space 82 of the spray passage 81 and each through-hole 91.

[0121] In this embodiment as well, the spraying mechanism can be configured to have an intrusion prevention function, such as each spray nozzle being equipped with a check valve, as described in Embodiment 1 of the spraying mechanism above. However, this is the same as described in Embodiment 1 of the spraying mechanism, so the explanation will be omitted.

[0122] While the rotor 9, i.e., the inner yoke 5, is rotating at high speed, a mist-like spray of cooling fluid is emitted from the through holes 91-95 toward the inner circumferential surface of the annular coil 7. As a result, the fine mist-like spray spreads evenly across the entire inner circumference of the coil 7, and further, as shown by arrows 103 in Figures 15 and 16, it spreads from the space 101 between the inner yoke 5 and the coil 7 toward the space 102 between the coil 7 and the outer yoke 6.

[0123] Figures 15(b) and 16(b) illustrate an example of an embodiment that more efficiently generates the flow indicated by the arrow 103 (Figures 15 and 16) described above.

[0124] As shown in Figures 15(b) and 16(b), the inner yoke 5 and the outer yoke 6 are connected radially at one end of the rotor 9 in the direction of the rotor's rotation center (the right end in Figures 15(b) and 16(b)) by an annular connecting wall 83 that extends circumferentially around the rotor's rotation center.

[0125] On the surface of this connecting wall 83 facing the coil 7 (the left surface in Figures 15(b) and 16(b)), an annular wing-shaped member 84 is provided, extending in the circumferential direction around the rotation center of the rotor 9.

[0126] The annular wing-shaped member 84 is provided with, for example, stirring blades 87a, 87b, 87c, 87d, ... on one surface of the annular body 86, which are inclined in the direction of rotation of the rotor 9 (direction of arrow 100) with a predetermined distance between them in the circumferential direction.

[0127] As the rotor 9 rotates, the blade-shaped member 84 rotates, which performs a centrifugal pump function that causes the aforementioned mist-like spray from the inner yoke 5 toward the inner circumferential surface of the coil 7 to flow from the space 101 between the inner yoke 5 and the coil 7 toward the space 102 between the coil 7 and the outer yoke 6.

[0128] As a result, the cooling fluid mist sprayed from the through holes 91-95 of the inner yoke 5 toward the inner surface of the annular coil 7 spreads efficiently and evenly throughout the entire inner circumference of the coil 7, and from the space 101 between the inner yoke 5 and the coil 7 toward the space 102 between the coil 7 and the outer yoke 6.

[0129] The outer magnets 16a, 16b, 16c, 16d, 16e, and 16f are arranged on the radially inner surface of the outer yoke 6 with a predetermined spacing between them in the circumferential direction. By filling the inner circumferential grooves 82a, 82b, 82c, 82d, 82e, and 82f of the outer yoke (Figure 13), which are grooves extending in the direction of the rotation center of the rotor 9, with packing material between adjacent outer magnets, the flow of the spray stream described above can be made even more efficient.

[0130] Figure 14 illustrates an example of such a structure. The space between adjacent outer magnets is filled with fillers 96a, 96b, 96c, 96d, 96e, ... into the inner circumferential grooves 82a, 82b, 82c, 82d, 82e, 82f (Figure 13) of the outer yoke that extend in the direction of the rotation center of the rotor 9 (Figure 14).

[0131] In both Embodiments 1 and 2 of the spray mechanism described above, the main heat-generating part of the rotating electric machines 1a and 1b is a fixedly positioned annular coil 7, and a spray mechanism is employed to spray a cooling fluid in a mist-like manner onto the coil 7 from multiple different positions.

[0132] Therefore, if the main heat-generating part of the rotating electric machines 1a and 1b is a fixedly positioned annular coil 7, it is possible to adopt a configuration that employs both the spray mechanism described in Embodiment 1 of the spray mechanism and the spray mechanism described in Embodiment 2 of the spray mechanism, although these are not shown in the figures.

[0133] Furthermore, if the main heat-generating part of the rotating electric machines 1a and 1b is an annular coil 7, the position where the temperature sensor 8 is attached near the coil 7 is not limited to the positions shown in Figures 1 and 2. Multiple sensors, such as two, three, etc., can be attached to a single annular coil 7 at predetermined intervals in the circumferential direction.

[0134] <Embodiment of spray control> In Embodiment 1 of the spray mechanism, the spray nozzles are arranged at multiple locations, for example, six locations, at predetermined intervals in the circumferential direction. However, the sprayed mist-like cooling fluid water is instantly agitated by the high-speed rotation of the rotor equipped with magnets.

[0135] Furthermore, in the second embodiment of the spray mechanism, spraying is performed from multiple through holes 91-95 facing the outer peripheral groove 83c of the inner yoke toward the inner circumferential surface of the coil 7, and as the rotor (inner yoke) rotates at high speed, the sprayed mist-like cooling fluid water is instantly agitated.

[0136] However, in either case, due to the heat capacity of coil 7, it takes a certain amount of time for the temperature of coil 7 to decrease. For example, it takes about 10 seconds.

[0137] Therefore, in controlling the start and stop of spraying from the spray nozzles 3a, etc. (Figures 1 and 2) and spray nozzles 3h (Figures 15 and 16) as described above, for example, after stopping spraying, the system can be configured to continue stopping spraying for about 30 seconds, and if the temperature detected by the sensor drops to the spray ON setting temperature during that time, spraying can be restarted.

[0138] Furthermore, the start and stop of mist-like spraying of cooling fluid via multiple spray nozzles 3a, etc., and spray nozzle 3h directed towards the heat-generating parts of the rotating electric machines 1a and 1b can be achieved, for example, by equipping the rotating electric machines 1a and 1b with spray control units that perform the control described below.

[0139] In the control by the spray control unit, spraying can be initiated by each spray nozzle when the detected temperature, detected by the temperature sensor 8 (which is the temperature detection unit), rises to the spray ON setting temperature.

[0140] The spray ON setting temperature for initiating spraying can be set based on the temperature at which the cooling fluid vaporizes. For example, if the cooling fluid is water, the temperature should be at least above 100°C, for example, 120°C.

[0141] On the other hand, in the control by the spray control unit, the control to stop the mist-like spraying of cooling fluid from multiple spray nozzles 3a, etc., and spray nozzle 3h can be configured to stop spraying from each spray unit immediately after spraying, stop spraying from each spray nozzle when the detected temperature detected by the temperature sensor 8 reaches the spray OFF setting temperature, or stop spraying from each spray nozzle when the amount of cooling fluid sprayed from each spray nozzle reaches a predetermined spray amount.

[0142] A control system that stops spraying from each spray nozzle immediately after spraying is advantageous because it prevents the risk of air or other gases flowing back into the spray nozzles after spraying stops.

[0143] In a control system that stops spraying from each spray nozzle when the detected temperature detected by the temperature sensor 8 reaches the spray OFF setting temperature, for example, the control system can be configured to stop spraying when the detected temperature detected by the temperature sensor 8, which is the temperature detection unit, has decreased by a predetermined temperature range from the start of spraying.

[0144] For example, by pre-setting temperature drop thresholds, such as when the detected temperature drops by 25°C from the start of spraying, 20°C from the start of spraying, or 15°C from the start of spraying, spraying can be stopped when the temperature reaches the spray OFF setting temperature, which is determined by detecting a temperature drop within the set threshold.

[0145] In a control system that starts spraying from each spray nozzle when the detected temperature, detected by the temperature sensing unit, reaches the spray ON setting temperature, and stops spraying from each spray nozzle when the detected temperature reaches the spray OFF setting temperature, it is possible to perform control that adjusts the amount of spray according to the temperature rise per unit time from the point when the detected temperature, which had decreased after the start of spraying, begins to rise again.

[0146] In a control system that starts spraying from each spray nozzle when the detected temperature reaches the spray ON setting temperature, and stops spraying from each spray nozzle when the detected temperature reaches the spray OFF setting temperature, it is also possible to adjust the amount of spray from each spray nozzle and to change the spray ON setting temperature and the spray OFF setting temperature.

[0147] Furthermore, in a control system that stops spraying from each spray nozzle when the amount of cooling fluid sprayed from each nozzle reaches a predetermined amount, the spray amount can be calculated from the heat capacity of the heat-generating part and the heat of vaporization of the cooling fluid. For example, it can be calculated from the heat capacity of the coil section 7 of the rotating electric machines 1a and 1b, which are the heat-generating parts, and the heat of vaporization of the cooling fluid.

[0148] <Embodiment of Cooling Fluid> In the rotating electric machines 1a and 1b described above, the cooling fluid can be water or antifreeze that has been treated to convert water into an antifreeze liquefaction solution.

[0149] As an antifreeze liquefaction treatment, alcohol can be added to water to prevent it from freezing.

[0150] The freezing point is 0°C for 0% alcohol concentration, approximately -5°C for 10%, approximately -12°C for 20%, and approximately -21°C for 30%. Anything higher than that becomes highly flammable and impractical.

[0151] Since the heat of vaporization of alcohol is 37% of that of water, in the case of antifreeze made by adding alcohol to water, the frequency of mist spraying will increase.

[0152] However, when rotating electric machine 1a is used in cold regions, it is advantageous in terms of temperature. It has good volatility, but its heat of vaporization is lower than that of water. Since alcohol retains its volatility even when mixed with water, it changes over time and the alcohol concentration decreases, so in cold regions, it is desirable to take measures such as periodically adding alcohol.

[0153] In the rotating electric machines 1a and 1b of this embodiment, the system used to suppress the temperature rise of the heat-generating part (coil 7) by spraying a cooling fluid in a mist-like manner, and to lower the temperature, can also be configured to use other cooling means, such as air cooling, in addition to the vaporization cooling described above.

[0154] In environments below 100°C, water conservation can be achieved, for example, by using air cooling.

[0155] As a countermeasure for cold regions or winter conditions, installing heaters along the water supply route is also an effective solution.

[0156] In addition to using dedicated water containers as a water source, it is also possible to use water from sources such as car air conditioners, filtered through a filter.

[0157] <Embodiment of a control system for controlling the mist-like spraying of a cooling fluid> Figure 5 is a schematic diagram showing an example of a control system that controls the mist-like spraying of the fluid used to drive and cool the rotating electric machines 1a and 1b described above.

[0158] Here, the above-mentioned rotating electric machine 1a will be described in an embodiment in which it is used as the wheel-in motors 1A and 1B of an electric vehicle.

[0159] The output from the drive control unit 19 in the controller 21 is received via the power line 23, and the wheel-in motors 1A and 1B are driven.

[0160] The spray control unit 20 of the controller 21 receives the output from temperature sensors 8A and 8B, which are composed of thermistors and are located in close proximity to the coil 7, the main heat-generating part of the wheel-in motors 1A and 1B.

[0161] The control at the start of spraying involves, for example, when the temperature of the heat-generating part (annular coil 7) detected by temperature sensors 8A and 8B reaches the spray ON setting temperature, the spray control unit 20 turns ON the cooling water supply means 22A and 22B, which are provided in the water supply pipe 4 that supplies cooling fluid to the spray nozzles 3A and 3B, so that mist-like spraying of the cooling fluid is started through the spray nozzles 3A and 3B provided on the rotating electric machines 1A and 1B (Figure 5). For example, a water pump or a solenoid valve can be used as the cooling water supply means 22A.

[0162] The spray nozzles 3a, etc. (Figures 1 and 2) described in Embodiment 1 of the spray mechanism, and the spray nozzle 3h (Figures 15 and 16) described in Embodiment 2 of the spray mechanism, are the same as the spray nozzles 3A and 3B shown in Figure 5.

[0163] The control for stopping spraying involves, for example, when the temperature of the heat-generating part (annular coil 7) detected by temperature sensors 8A and 8B reaches the spray OFF setting temperature, the spray control unit 20 turns OFF the cooling water supply means 22A, which is provided in the water supply pipe 4 that supplies cooling fluid to the spray nozzles 3A and 3B, so that the mist-like spraying of cooling fluid via the spray nozzles 3A and 3B provided in the rotating electric machines 1A and 1B is stopped (Figure 5).

[0164] Furthermore, the control during spray cessation involves, for example, the control of the spray control unit 20 to turn OFF the cooling water supply means 22A, which is provided in the water supply pipe 4 that supplies the cooling fluid to the spray nozzles 3A and 3B, when a predetermined spray volume, for example, 1 milliliter from each spray nozzle, is reached after the mist-like spraying of the cooling fluid from the spray nozzles 3A and 3B has started as described above (Figure 5).

[0165] Furthermore, as shown in Figure 1, each spray nozzle 3a, etc., can be equipped with a check valve 13a, etc., and the control of stopping spraying by the spray control unit 20 described above can be entrusted to these check valves 13a, etc.

[0166] In this case, after control at the start of spraying, the control configuration can be configured such that spraying is stopped immediately afterward by a check valve 13a, etc.

[0167] The control by the spray control unit 20 is configured to turn on the cooling water supply means 22A and 22B so that spraying by the spray nozzles 3A and 3B begins when the detected temperature of the heat-generating part (ring-shaped coil 7) detected by the temperature sensors 8A and 8B reaches the spray ON setting temperature, and to turn off the cooling water supply means 22A and 22B so that spraying by the spray nozzles 3A and 3B stops when the detected temperature reaches the spray OFF setting temperature. Here, as described above, the control can also be configured to adjust the amount of spray according to the temperature rise per unit time from the point when the detected temperature, which had decreased after the start of spraying, begins to rise.

[0168] Furthermore, the control by the spray control unit 20 is configured to turn on the cooling water supply means 22A and 22B so that spraying by the spray nozzles 3A and 3B begins when the detected temperature of the heat-generating part (annular coil 7) detected by the temperature sensors 8A and 8B reaches the spray ON setting temperature, and to turn off the cooling water supply means 22A and 22B so that spraying by the spray nozzles 3A and 3B stops when the detected temperature reaches the spray OFF setting temperature. Here, as described above, it is also possible to adjust the amount of spray from the spray nozzles 3A and 3B and change the spray ON setting temperature and the spray OFF setting temperature.

[0169] Furthermore, the control by the spray control unit 20 is configured to turn on the cooling water supply means 22A and 22B so that spraying by the spray nozzles 3A and 3B begins when the detected temperature of the heat-generating part (annular coil 7) detected by the temperature sensors 8A and 8B reaches the spray ON setting temperature, and to turn off the cooling water supply means 22A and 22B so that spraying by the spray nozzles 3A and 3B stops when the amount of cooling fluid sprayed from the spray nozzles 3A and 3B reaches a predetermined spray amount. Here, as described above, the amount of spray from the spray nozzles 3A and 3B can also be calculated and controlled from the heat capacity of the heat-generating part (annular coil 7) and the heat of vaporization of the cooling fluid.

[0170] Furthermore, even with the control described above, if an overheating condition occurs, the amount of cooling fluid supplied to the spray nozzles 3A and 3B can be increased by controlling the cooling water supply means 22A and 22B, which consist of a water pump and solenoid valve, etc., so that even if an excessive spraying condition occurs, the system can be switched to a cooling-priority mode as an emergency measure.

[0171] Furthermore, in the embodiment shown in Figure 5, there is only one water tank 50 containing the cooling fluid, and each of the cooling water supply means 22A, 22B, which consists of a water pump and solenoid valve that supplies the cooling fluid to the heat-generating parts (annular coils 7) of the wheel-in motors 1A, 1B, is supplied with cooling fluid from the water tank 50. However, instead of this, it is possible to have a configuration in which a separate water tank is provided to supply the cooling fluid to each of the cooling water supply means 22A, 22B.

[0172] Furthermore, in Figure 5, the drive control unit 19 and spray control unit 20, both located on a single controller 21, controlled the drive of the wheel-in motors 1A and 1B, and controlled the ON / OFF status of the cooling water supply means 22A and 22B, thereby controlling the start and stop of spraying from the spray nozzles 3A and 3B, respectively, which are located on the wheel-in motors 1A and 1B.

[0173] Alternatively, two controllers, each equipped with a drive control unit and a spray control unit, can be used to control the drive of the wheel-in motors 1A and 1B, and the ON / OFF control of the cooling water supply means 22A and 22B, thereby controlling the start and stop of spraying from the spray nozzles 3A and 3B, which are respectively equipped on the wheel-in motors 1A and 1B.

[0174] In the embodiment shown in Figure 1, by setting the vertical height of the water tank 50, which contains the cooling fluid supplied via the water supply pipe 4, higher than the vertical height of the spray nozzle 3a, etc., it is possible to create a structure in which air does not enter the cooling fluid supplied via the water supply pipe 4.

[0175] Furthermore, as shown in the illustrated embodiment, if a check valve 13a, etc. is provided for each spray nozzle 3a, etc., backflow of air can be prevented.

[0176] In the aforementioned rotating electric machine 1a, which is equipped with an annular coil 7, heat is generated not only in the coil 7, which is the main heat-generating part, but also in the wiring between the power lines 17a, 17b, and 17c and the coil 7. Therefore, it is desirable to have a structure that allows the mist-like spray from each spray nozzle 3a, etc., to reach these wiring parts as well.

[0177] In the control by the spray control unit 20 described above, the timing (seconds) of the first mist spray is: {(Spray temperature) - (Starting temperature)} / {(Motor heat generation) - (Motor natural air cooling)} / (Coil heat capacity) It can be set as follows. Here, Motor heat generation = copper loss + other heat generation besides copper loss.

[0178] "Spray temperature" refers to the temperature of the heat-generating part (coil 7) when spraying begins. Since it is evaporative cooling, if the cooling fluid is water, the temperature will be at least above 100°C.

[0179] "Motor heat generation" in general motors mainly consists of copper loss and iron loss (coreless motors have no iron loss), as well as mechanical loss and other losses. Generally, copper loss and iron loss can be calculated, while other losses can be determined by measurement. {(Motor input) - (Motor output)} - ​​{Copper loss + Iron loss} = {Machine loss + Other losses}

[0180] "Natural air cooling of a motor" is calculated from the motor's surface area, surface shape, and surface material. This can also be determined from temperature rise tests. The heat dissipation coefficient for natural air cooling (K / W) is given by temperature rise (K) / loss (W).

[0181] The "heat capacity of a coil" can be calculated from the total weight of the copper and the heat capacity of the copper.

[0182] "Motor heat generation" can be calculated from {motor input (voltage × current) - motor output (rotational speed × torque)}.

[0183] The timing (in seconds) for spraying from the second time onwards during continuous operation is: (Spray volume × heat of vaporization of water) / (heat generated by motor - heat dissipated by motor) It can be set as follows.

[0184] The temperature of the heating element (coil 7) during spraying should be above 100°C and below a predetermined temperature, taking into account both the initial 100°C temperature and the temperature rise after spraying. For example, in the case of a Class F insulated coil, it should be between 110°C and 140°C.

[0185] Furthermore, in the control described above, the cooling fluid can be sprayed in a volume calculated by the following equation. If the volume is too small, the temperature reduction will be insufficient, and additional spraying will be performed. Even if there is a slight excess, since the spraying is instantaneous, there is little risk of loss of cooling fluid.

[0186] Volume of cooling fluid to be sprayed = Desired temperature reduction / {η × (Heat of vaporization of 1 mL of cooling fluid to be sprayed / Heat capacity of the coil)} Here, η is the efficiency, which is the amount of heat actually removed from the coil divided by the heat of vaporization.

[0187] Furthermore, the desired temperature reduction is calculated as follows: Volume of the cooling fluid to be sprayed × {η × (heat of vaporization of 1 mL of the cooling fluid to be sprayed / heat capacity of the coil)}.

[0188] Even when the spraying operation is performed with the spraying start temperature set to 121°C (e.g., spraying ON setting temperature), and the spraying stop temperature set to 119°C (e.g., spraying OFF setting temperature), heat generation continues after spraying starts until the temperature begins to drop, and the temperature tends to exceed the target set temperature (e.g., 130°C). Furthermore, cooling proceeds with a delay after spraying stops, and the temperature tends to fall below the target set temperature (e.g., 101°C).

[0189] In other words, the delay in the cooling effect can lead to excessive temperature increases or decreases, and as time progresses, the range of temperature decreases widens, so even if the goal is to keep the temperature difference to a maximum of 20 degrees, it could potentially reach 50 degrees.

[0190] This temperature change causes thermal shock to the coil (with the insulating film), leading to a slight change in the coil's shape.

[0191] The gap between the motor coil and the magnet is narrow, about 1 mm, so slight changes in this shape due to contact between the non-rotating coil and the rotating magnet may lead to motor failure.

[0192] Therefore, in order to mitigate this thermal shock, the spray volume can be adjusted according to the measured temperature rather than being a fixed amount. In other words, when the temperature of the heating element exceeds the spray ON setting temperature A, the liquid is sprayed, and when it reaches the spray OFF setting temperature B, the spraying of the liquid is stopped. However, in order to suppress the excessive temperature rise and fall that occur due to the delay in the cooling effect, the amount of cooling fluid sprayed is adjusted according to the temperature rise per unit time from the point when the detected temperature, which had decreased after the start of spraying, begins to rise again.

[0193] The amount of adjustment will vary depending on the motor characteristics, but this adjustment can be based on the current value, or it can be done by accumulating actual measurement data and adjusting it using AI (artificial intelligence).

[0194] The spray volume (total value from multiple spray nozzles) can be estimated based on the heat capacity of the coil and the heat of vaporization of the cooling fluid (e.g., water). Spray volume control is handled by the system shown in Figure 5.

[0195] As mentioned above, excessive temperature changes due to excessive temperature rise or fall result in thermal shock to the coil (with insulating film), and generally, the magnetic flux of a magnet drops sharply (demagnetizes) above 160°C. Therefore, according to the present invention, which applies control to the drive of the rotating electric machine by spraying a cooling fluid in the form of a mist toward the heat-generating part of the rotating electric machine, it is possible not only to suppress thermal shock to the coil but also to suppress the sharp drop in magnetic flux (demagnetization) caused by the magnet being placed in a high-temperature state.

[0196] <Water spray experiment results> In the rotating electric machine 1a shown in Figure 1, the spray mechanism according to Embodiment 1 of the spray mechanism described above is adopted, and the water spray experimental data when water is used as the cooling fluid is shown in the graph in Figure 12.

[0197] In this graph, the first two peaks represent 60A, the next three peaks represent 90A, and the following single peak represents 120A.

[0198] It was found that the temperature gradient becomes steeper with each current, and the temperature peak also increases in proportion to the temperature gradient. The temperature gradient is approximately proportional to the current.

[0199] Therefore, in order to adjust the spray volume according to the current, the pump output can be adjusted based on the current.

[0200] In addition to changing the flow rate, it is also preferable to change the settings for the spray ON setting temperature and the spray OFF setting temperature. For example, if the peak temperature rises due to a temperature gradient, not only the flow rate of the pump but also the temperature at which the cooling water supply means 22A and 22B in Figure 3, which are realized by a water supply pump, are turned ON (spray ON setting temperature) should be changed (lowered) according to the degree of the increase. Specifically, if the current (for example, a 10-second average) that acts as a substitute for the temperature gradient increases, the pump duty cycle of the water supply pump should be increased, and the spray ON setting temperature and spray OFF setting temperature should be set higher.

[0201] An example of this control method is shown in Table 1 below. [Table 1]

[0202] <One embodiment as a wheel-in motor> Figure 8 illustrates an example in which the rotating electric machine 1a of the above-described embodiment is used as a wheel-in motor in the rear wheel (driving wheel) of a four-wheeled electric vehicle.

[0203] As described above, in the rotating electric machine 1a, the rotational motion transmission mechanism that provides the rotational motion driving force for the rotational motion of the casing 11 is housed within the casing 11 in the radial direction. Therefore, the structure is such that the motor and the gears constituting the rotational motion transmission mechanism are incorporated into each of the four driving wheels 31 of the electric vehicle.

[0204] Furthermore, this rotating electric machine 1a fits within the tire width of the driving wheels 31 of a four-wheeled electric vehicle, eliminating the need for shafts to connect each of the driving wheels 31.

[0205] Since there is no need for an axle to connect the driving wheels 31, the gears under the vehicle body become unnecessary.

[0206] Therefore, as shown in Figures 8(b) to 8(d), the underside of the vehicle can be lowered to make the entire vehicle lower, or conversely, the underside of the vehicle can be raised to make it high enough to easily pass over sharp bumps in the road.

[0207] When the rotating electric machine 1a of the above embodiment was incorporated as a wheel-in motor into the rear wheels (one for each driving wheel) of a four-wheeled electric vehicle and its driving performance was simulated with the following specifications, the results shown in Table 2 were obtained.

[0208] Motor type: 3-phase brushless coreless motor Voltage: 115V Lithium-ion battery used Motor current: Rated 130A (per motor) Motorized vehicle weight: 795kg (Total weight: 1,200kg) Wheel outer diameter: φ532mm In this simulation, water was used as the cooling fluid, and the spray mechanism described in Embodiment 1 of the spray mechanism was adopted. The control system described in "Embodiment of a control system for controlling mist-like spraying of cooling fluid" was used to start spraying when the detected temperature, detected by the temperature detection unit, reached the spray ON setting temperature, and to stop spraying when the detected temperature reached the spray OFF setting temperature.

[0209] [Table 2]

[0210] <Other embodiments of rotating electric machines> In the above description, a rotating electric machine according to one embodiment of the present invention has been described in an example in which it is configured as a coreless motor, but the rotating electric machine of the present invention can also be configured as a cored motor.

[0211] In this case, as shown in Figures 9 and 10, the spraying by the spraying unit described above is performed on the slots in the cored motor.

[0212] For example, as shown in Figure 10, a spray unit 48 is provided to spray cooling fluid towards the slot portion of the cored motor, in which the shaft 42, stator core 43, rotor core 44, and coil 47 are arranged inside the casing 11.

[0213] As shown in Figure 9, the spray section consists of multiple spray nozzles 27a and 27b that spray cooling fluid toward the slots. Figure 9 is a diagram illustrating an example in which the rotating electric machine of the present invention is used in a cored in-wheel motor, and it illustrates the positions of the spray nozzles 27a and 27b that spray cooling fluid toward the slots when viewed from the side section 28. Cooling fluid is sprayed toward the slots from multiple locations, namely the spray nozzles 27a and 27b.

[0214] Figure 11 illustrates the schematic configuration when the rotating electric machine of the present invention is used in a flat motor (also known as a surface-facing motor) 70, which is sometimes used as a fan motor, in which the coil side and the magnet side face each other in a plane and parallel to one another.

[0215] The shaft 72, which extends vertically through the casing 71 of the flat motor 70 in Figure 11(a), is supported by the casing 71 by bearings and seals 73a and 73b. The magnet yoke 76, coil 74, and coil yoke 75, which support the magnet 77, are arranged within the closed internal space of the casing 71.

[0216] If there is a gap between the coil yoke 75 and the coil 74, and the coil yoke 76 rotates with it, it becomes a coreless motor. If the coil 74 is in close contact and does not rotate like the coil yoke 74, it becomes a slotless motor. In the case of coreless motors, there are also double-magnet types where a magnet is attached to the coil side of the coil yoke as well.

[0217] Coil 74 can be a single-phase coil, and Figure 11 illustrates a single-phase example. In a three-phase system, coils 74 would overlap.

[0218] In the embodiment shown in Figure 11, multiple spray units are provided to spray cooling fluid toward the coil 74, which is the main heat-generating part, and the spraying is performed in the directions indicated by arrows 80a and 80b.

[0219] Furthermore, exhaust is carried out through a steam recovery pipe, which has an opening within the enclosed space inside the casing 71 and extends outward from the casing 71, as indicated by arrow 81.

[0220] The rotating electric machine of the present invention is not limited to coreless motors or slotless motors, but coreless motors and slotless motors are particularly well-suited to utilizing the evaporative cooling method of the present invention because a cooling fluid can be directly sprayed onto the entire coil, which is the main heat-generating part, and heat can be uniformly removed from the entire coil.

[0221] In this case, the coil shape is preferably annular around the shaft, considering the space required to incorporate gears and other components inside the motor, as in an in-wheel motor. However, as mentioned above, a flat coil can also be effective. [Industrial applicability]

[0222] The present invention applies control to the drive of a rotating electric machine by spraying a cooling fluid in the form of a mist onto the heat-generating parts of the rotating electric machine, which are located within the enclosed space of the rotating electric machine. By spraying a cooling fluid in the form of a mist onto the main heat-generating parts of the motor, such as the coils, and utilizing the heat of vaporization when the fluid vaporizes, the heat-generating parts of the motor can be cooled, thereby improving the output (torque) of the motor.

[0223] For example, when a cooling fluid is sprayed in a mist form, the motor's output (torque) can be increased by three to five times, either temporarily or continuously, compared to when the mist spraying is not performed.

[0224] Furthermore, as described above, the vaporized cooling fluid can be condensed and reused within the system.

Claims

1. A temperature detection unit that detects the temperature of the heat-generating part of the rotating electric machine, which is located in the enclosed space of the rotating electric machine, Multiple spraying mechanisms that spray cooling fluid in a mist-like form from multiple different positions toward the heat-generating section, A steam recovery pipe having an opening in the aforementioned space and extending from the aforementioned space toward the outside of the rotating electric machine, A spray control unit controls the start and stop of spraying the cooling fluid by the spray mechanism. A rotating electric machine equipped with this feature.

2. The rotating electric machine according to claim 1, wherein the heat-generating part that is sprayed with the cooling fluid by the spraying mechanism is a coil in a coreless motor or a slotless motor.

3. The rotating electric machine according to claim 2, wherein the coil is annular, and a plurality of the spraying mechanisms are arranged toward the annular coil at predetermined intervals between them in the circumferential direction.

4. The heating element is an annular coil fixedly positioned in the space, The annular coil is provided with an inner yoke and an outer yoke, each having a plurality of magnets on the inner and outer surfaces facing the coil in the radial direction, and a rotor is arranged in the space that rotates in the circumferential direction of the coil. Multiple spraying mechanisms spray from the inner yoke toward the inner surface of the annular coil. The rotating electric machine according to claim 1.

5. The multiple magnets arranged on the circumferential surface of the inner yoke are arranged with an inner yoke outer circumferential groove, which is a groove extending in the direction of the rotor's rotation center, interposed between them in the circumferential direction. The spray mechanism includes a plurality of through holes that penetrate the inner yoke radially and face the outer groove of the inner yoke. The rotating electric machine according to claim 4.

6. The inner yoke and the outer yoke are connected at one end in the direction of the rotor's rotation center by an annular connecting wall that extends circumferentially around the rotor's rotation center and connects them radially. An annular, wing-shaped member extending in the circumferential direction with respect to the rotor's rotation center is provided on the surface of the connecting wall facing the coil. As the rotor rotates, the vane-shaped member rotates, thereby performing a centrifugal pump function that causes the spray from the inner yoke toward the inner circumferential surface of the coil to flow from the space between the inner yoke and the coil toward the space between the coil and the outer yoke. The rotating electric machine according to claim 4 or 5.

7. The rotating electric machine according to claim 1 or claim 4, wherein the spraying mechanism has a function to prevent gas from entering the spraying mechanism from the space after spraying has stopped.

8. The control by the spray control unit is, When the temperature detected by the temperature detection unit reaches the spray ON setting temperature, spraying by each spray unit is initiated. Regarding stopping the spraying, Immediately after spraying, stop spraying from each spray unit. When the detected temperature reaches the spray OFF setting temperature, spraying from each spray unit is stopped, or When the amount of cooling fluid sprayed from each spray unit reaches a predetermined amount, the spraying from each spray unit is stopped. It is due to one of the following reasons The rotating electric machine according to claim 1 or claim 4.

9. The rotating electric machine according to claim 8, in the control by the spray control unit, which starts spraying from each spray unit when the detected temperature detected by the temperature detection unit reaches the spray ON setting temperature, and stops spraying from each spray unit when the detected temperature reaches the spray OFF setting temperature, the control unit adjusts the amount of spray according to the temperature rise per unit time from the point when the detected temperature, which had decreased after the start of spraying, begins to rise.

10. The rotating electric machine according to claim 8, wherein the spray control unit controls the amount of spray from the spray units and also controls the spray ON setting temperature and the spray OFF setting temperature, in which spraying by each spray unit is started when the detected temperature detected by the temperature detection unit reaches the spray ON setting temperature, and spraying from each spray unit is stopped when the detected temperature drops below the spray OFF setting temperature.

11. The rotating electric machine according to claim 8, wherein the spray control unit controls the operation by which spraying is started by each spray unit when the detected temperature detected by the temperature detection unit reaches the spray ON setting temperature, and stops spraying from each spray unit when the amount of cooling fluid sprayed from each spray unit reaches a predetermined spray amount, wherein the amount of spray is calculated from the heat capacity of the heat generating unit and the heat of vaporization of the cooling fluid.

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