Motor cooling system

Abstract

To provide a motor cooling system capable of efficiently cooling the coil ends of a stator coil.SOLUTION: A motor cooling system S1 supplies cooling oil to each part of a motor 1, and includes a heat exchanger, a stator 10 having a stator core 11 on which a stator coil is mounted, a rotor 40 having a rotor core 41, and stator-side and rotor-side oil passages 80, 90 that can supply oil that has passed through the heat exchanger to the stator 10 and the rotor 40. The stator 10 is configured such that oil that has passed through the stator-side oil passage 80 is supplied to the first coil end 17a without flowing inside the stator core 11. The rotor 40 is configured such that oil that has passed through the rotor-side oil passage 90 is supplied to the first coil end 17a from the radially inner side without flowing inside the rotor core 41.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a motor cooling system, and more particularly to a motor cooling system that supplies cooling oil to each part of a motor. [Background technology]

[0002] As electric vehicles become more widespread, there is a demand for improvements in the mountability and productivity of the motors that drive them, as well as for easier deployment in a wider range of vehicle models and lower costs. To achieve these goals, it is necessary to reduce the size of the motor while maintaining its output, in other words, to increase the output density of the motor.

[0003] Increasing the power density of a motor inevitably requires increasing the density of the current flowing through the stator coil, but increasing the current density in a motor can lead to temperatures in the stator core, stator coil, rotor core, and (in the case of a synchronous motor) permanent magnets, which can sometimes lead to a decrease in motor output. In particular, the coil ends of the stator coil that protrude from both axial ends of the stator core are one of the areas that require high cooling, as refrigerants and the like are difficult to reach and the coil coating (insulating material) can melt if they become too hot.

[0004] Therefore, for example, Patent Document 1 discloses a cooling structure for a rotating electric machine that has a refrigerant flow path extending in the axial direction above the stator core, and includes a stator cooling means that cools the coils by dripping refrigerant onto the coil ends from a refrigerant drip section, which is a hole formed in the refrigerant flow path, and a cooling means that cools the coils by ejecting the refrigerant from a discharge hole in the axial flow path (a cavity inside the rotating shaft) through which the refrigerant flows and circulating inside the rotor, radially outward by centrifugal force and hitting the coil ends. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-146387 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the device disclosed in Patent Document 1, the refrigerant that has circulated inside the rotor, in other words, the refrigerant that has been heated to a certain degree by cooling the inside of the rotor, is applied to the coil ends. Therefore, depending on the operating conditions, the coil ends may not be sufficiently cooled, and in this respect, there is room for improvement in the device disclosed in Patent Document 1.

[0007] The present invention has been made in view of the above points, and an object of the present invention is to provide a motor cooling system that can efficiently cool the coil ends of the stator coil. [Means for solving the problem]

[0008] In order to achieve the above object, the motor cooling system of the present invention supplies low-temperature oil that is not used to cool the stator core or rotor core to the coil ends from multiple directions simultaneously.

[0009] Specifically, the present invention is directed to a motor cooling system that supplies oil for cooling to various parts of a motor.

[0010] The motor cooling system comprises a cooling means for cooling oil, a stator having a cylindrical stator core to which a stator coil is attached, a rotor having a cylindrical rotor core arranged inside the stator core, a stator-side oil passage capable of supplying oil that has passed through the cooling means to the stator, and a rotor-side oil passage capable of supplying oil that has passed through the cooling means to the rotor, wherein the stator is configured so that at least a portion of the oil that has passed through the stator-side oil passage is supplied to at least one axial coil end of the stator coil without flowing within the stator core, and the rotor is configured so that at least a portion of the oil that has passed through the rotor-side oil passage is supplied from the radially inner side to at least one axial coil end without flowing within the rotor core.

[0011] According to this configuration, of the oil that has passed through the cooling means, in other words, that is maintained at a relatively low temperature (for convenience, also referred to as "fresh oil"), at least a portion of the oil that has passed through the stator side oil passage is supplied to the coil end on at least one axial side (hereinafter simply referred to as "one side") without flowing within the stator core, so that the fresh oil can cool, for example, the radial outside of the coil end or the radial center of the coil end.

[0012] Furthermore, at least a portion of the fresh oil that passes through the rotor-side oil passage is supplied to at least one coil end without flowing inside the rotor core, so that the fresh oil can cool the coil end from the radially inner side (hereinafter simply referred to as the "inside").

[0013] In this way, fresh oil that has not been used to cool the stator core or rotor core is supplied to the coil ends from multiple directions at the same time, allowing the coil ends to be cooled efficiently.

[0014] In addition, in the motor cooling system, the stator may be configured so that a portion of the oil that has passed through the stator-side oil passage is supplied to the coil end on one side in the axial direction, and at least a portion of the remaining oil is supplied axially into the stator core, and the rotor may be configured so that a portion of the oil that has passed through the rotor-side oil passage is supplied to the coil end on one side in the axial direction, and the remaining oil is supplied axially into the rotor core.

[0015] With this configuration, a portion of the oil that has passed through the stator side oil passage is supplied to one of the coil ends, and at least a portion of the remaining oil is supplied axially into the stator core, thereby maintaining the state in which one of the coil ends is cooled by fresh oil while also cooling the inside of the stator core with fresh oil.

[0016] Furthermore, a portion of the oil that passes through the rotor-side oil passage is supplied to one of the coil ends, and the remaining oil is supplied axially into the rotor core, so that the coil end on one side is cooled from the inside by fresh oil while also cooling the inside of the rotor core by fresh oil.

[0017] In this way, fresh oil is supplied not only to one coil end, but also to the stator core and rotor core at the same time, allowing each part of the motor, including the coil ends, to be efficiently cooled.

[0018] Furthermore, in the motor cooling system, the stator may be configured so that a portion of the remaining oil that has passed through the stator-side oil passage is supplied into the stator core, and another portion of the remaining oil is supplied to the coil end on the other axial side without flowing through the stator core, and the rotor may be configured so that the oil supplied into the rotor core reaches the end on the other axial side of the rotor core, and then is supplied from the radially inner side to the coil end on the other axial side.

[0019] With this configuration, another portion of the remaining oil that has passed through the stator-side oil passage is supplied to the coil end on the other axial side (hereinafter simply referred to as the "other side"), so that the coil end on the other side can also be cooled by fresh oil.

[0020] Furthermore, since the oil supplied into the rotor core is supplied to the coil end on the other side from the inside, it is possible to cool not only the coil end on one side but also the coil end on the other side from the inside, even though the oil has cooled the inside of the rotor core.

[0021] In this way, fresh oil is not only supplied to the coil end on one side, the stator core, and the rotor core simultaneously, but also to the coil end on the other side, allowing each part of the motor, including the coil end on one side, to be cooled efficiently over a wider area.

[0022] In addition, in the motor cooling system, the stator may be configured so that oil that has passed through the stator-side oil passage passes through an annular space formed concentrically with the stator core in an oil plate attached to one axial end of the stator core, and is distributed to the coil ends on one axial side and within the stator core; and the rotor may be configured so that oil that has passed through the rotor-side oil passage passes through an annular space formed concentrically with the rotor core in an end plate attached to one axial end of the rotor core, and is distributed to the coil ends on one axial side and within the rotor core.

[0023] With this configuration, by utilizing an oil plate attached to one axial end of the stator core and an end plate attached to one axial end of the rotor core, it is possible to easily realize a configuration in which the coil ends are cooled by fresh oil without flowing inside the stator core or rotor core.

[0024] Furthermore, fresh oil supplied axially into the stator core or rotor core passes through the annular space formed in the oil plate or end plate before being distributed within the stator core or rotor core, making it possible to evenly supply fresh oil to, for example, oil passages formed in the stator core or oil passages formed in the rotor core.

[0025] In this way, fresh oil is not only supplied to one coil end, but is also supplied evenly within the stator core and rotor core, allowing each part of the motor, including the coil ends, to be cooled more efficiently.

[0026] Furthermore, in the motor cooling system, the rotor core may have a plurality of axially extending magnet holes formed therein into which permanent magnets are embedded, the stator may be configured so that oil supplied into the stator core flows axially between slots formed in the stator core and the stator coil inserted into the slots, and the rotor may be configured so that oil supplied into the rotor core flows axially through the magnet holes.

[0027] With this configuration, oil flows axially through the stator core between the slots and the stator coil, and through the magnet holes in which the permanent magnets are embedded, allowing fresh oil to directly cool the stator coil and permanent magnets, thereby more reliably and efficiently cooling each part of the motor, including the coil ends. [Effects of the Invention]

[0028] As described above, the motor cooling system according to the present invention can efficiently cool the coil ends of the stator coil. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a vertical cross-sectional view schematically showing a main part of a motor cooling system according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a block diagram illustrating an example of a cooling system in an electric vehicle. [Figure 3] FIG. 2 is a diagram schematically illustrating a stator. [Figure 4] FIG. 2 is a diagram schematically illustrating an oil plate. [Figure 5] FIG. 2 is a perspective view schematically showing a rotor. [Figure 6] FIG. 2 is a diagram schematically illustrating an oil passage and oil flow in a rotor. [Figure 7] FIG. 4 is a vertical cross-sectional view schematically showing a motor cooling system according to a modified example of the first embodiment. [Figure 8] FIG. 4 is a vertical cross-sectional view schematically showing a motor cooling system according to a second embodiment of the present invention. [Figure 9] FIG. 2 is a diagram schematically illustrating a stator. [Figure 10] FIG. 2 is a diagram schematically illustrating a rotor. [Figure 11] FIG. 2 is a diagram schematically illustrating an oil passage and oil flow in a rotor. [Figure 12] FIG. 10 is a vertical cross-sectional view schematically showing a motor cooling system according to a third embodiment of the present invention. [Figure 13] FIG. 2 is a diagram schematically illustrating an oil plate and an end plate. [Figure 14] FIG. 2 is a perspective view illustrating the flow of oil in the stator. [Figure 15] FIG. 2 is a diagram schematically illustrating an oil passage and oil flow in a rotor. [Figure 16] FIG. 10 is a perspective view schematically showing a rotor core according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the symbol AC indicates the axis of a synchronous motor, the symbol OS indicates the output shaft side (the other side in the axial direction (the direction in which the axis AC extends)), and the symbol AOS indicates the anti-output shaft side (one side in the axial direction).

[0031] (Embodiment 1) - Motor cooling system overview - FIG. 1 is a longitudinal cross-sectional view showing a schematic representation of a main portion of a motor cooling system S1 according to this embodiment. Furthermore, FIG. 2 is a block diagram showing a schematic representation of an example of a cooling system S for an electric vehicle. This motor cooling system S1 constitutes part of the cooling system S for the electric vehicle shown in FIG. 2, and as shown in FIG. 1, supplies cooling oil to a first coil end 17a (each part of the motor 1) of a stator coil 17 (see FIG. 3). The motor cooling system S1 includes a heat exchanger (cooling means) 8 that cools the oil, a motor 1 having a stator 10 and a rotor 40, a stator-side oil passage 80 that can supply the oil that has passed through the heat exchanger 8 to the stator 10, and a rotor-side oil passage 90 that can supply the oil that has passed through the heat exchanger 8 to the rotor 40.

[0032] -Cooling System- As shown in FIG. 2, the cooling system S includes an inverter cooling system 3 and a motor cooling system S1, with a heat exchanger 8 interposed between the inverter cooling system 3 and the motor cooling system S1.

[0033] The inverter cooling system 3 has a circulation path 3a through which the coolant circulates, and an inverter 5, a radiator 6, and a water pump 7 that circulates the coolant, each of which is provided on the circulation path 3a. In this inverter cooling system 3, heat generated by the inverter 5 is absorbed by the coolant, and the heat absorbed by the coolant is dissipated to the outside by the radiator 6, thereby maintaining the coolant and the inverter 5 at low temperatures.

[0034] On the other hand, the motor cooling system S1 has a circulation path 4 through which oil circulates, a motor 1, and an oil pump 9 that pumps oil to the motor 1, each of which is provided on the circulation path 4. In this motor cooling system S1, the heat generated by the motor 1 is absorbed by the oil, and the oil that has absorbed the heat collects at the bottom of the motor housing (not shown) and then returns to the circulation path 4. In this motor cooling system S1, the heat absorbed by the oil is absorbed by the coolant through indirect heat exchange between the circulation paths 3a and 4 in the heat exchanger 8, and is then radiated to the outside by the radiator 6, thereby maintaining the oil at a relatively low temperature.

[0035] In this embodiment, the cooling system S configured as described above allows oil (also referred to as "fresh oil" for convenience) maintained at a relatively low temperature to be sent at an appropriate rate to the stator 10 side through the stator side oil passage 80 and to the rotor 40 side through the rotor side oil passage 90.

[0036] - Stator - FIG. 3 is a diagram schematically illustrating the stator 10. More specifically, FIG. 3(a) is a perspective view showing the entire stator 10, and FIG. 3(b) is an enlarged perspective view showing the first coil end 17a. Note that in FIG. 3(a), the stator coil 17 is omitted from illustration to make the drawing easier to see. As shown in FIG. 3, the stator 10 includes a cylindrical stator core 11, the stator coil 17 attached to the stator core 11, first and second oil plates 20, 20′, and first and second oil guides 30, 30′.

[0037] <Stator core> 3(a), the stator core 11 is configured by laminating, for example, a plurality of electromagnetic steel plates in the axial direction, and has a cylindrical yoke 12 and a plurality of teeth 13 that protrude radially inward from the inner peripheral surface of the yoke 12 and are arranged in the circumferential direction at intervals from one another. By arranging the plurality of teeth 13 in the circumferential direction at intervals from one another in this manner, a plurality of slots 15 that are defined (defined) by adjacent teeth 13 and that are open radially inward are formed in the stator core 11.

[0038] <Oil plate> FIG. 4 is a schematic diagram of the first oil plate 20. More specifically, FIG. 4(a) is a perspective view showing the upper part of the first oil plate 20, FIG. 4(b) is a cross-sectional view taken along line bb in FIG. 4(a), and FIG. 4(c) is a perspective view showing the flow of oil in the stator 10. The first oil plate 20 on the AOS on the side opposite the output shaft in the axial direction (hereinafter simply referred to as the "anti-output shaft AOS") and the second oil plate 20' on the OS on the side opposite the output shaft in the axial direction (hereinafter simply referred to as the "output shaft OS") are both made of a non-magnetic material such as resin, have an annular shape, and have a cross-sectional outer shape similar to that of the stator core 11. Specifically, the first oil plate 20 has a portion corresponding to the yoke 12 (referred to as the "yoke 22" for convenience), a portion corresponding to the teeth 13 (referred to as the "teeth 23" for convenience), and a portion corresponding to the slots 15 (referred to as the "slots 25" for convenience). The cross-sectional outer shape of the second oil plate 20' is similar to that of the first oil plate 20, and therefore a description thereof will be omitted.

[0039] The first oil plate 20 is configured, for example, by combining two members in the axial direction, and has a space formed therein, as shown in Figures 4(a) and 4(b). More specifically, inside the first oil plate 20, an annular space 26 is defined on the radially outer side by an annular outer wall portion 21, and is formed concentrically with the first oil plate 20. The upper end of the outer wall portion 21 is cut out, and this cutout portion serves as an oil inlet port 29 for introducing oil into the annular space 26.

[0040] Additionally, inside first oil plate 20, a portion that defines the radially inner side of annular space 26 is recessed radially inward to form first radial oil passages 27 that extend in the same direction as teeth 23. A through hole 27a that opens to the anti-output-shaft side AOS is formed at the tip end (radially inner end) of first radial oil passage 27.

[0041] Furthermore, inside first oil plate 20, a portion that defines the radially inner side of annular space 26 is recessed radially inward to be shallower than first radial oil passage 27, thereby forming second radial oil passages 28 that extend in the same direction as teeth 23. A through hole 28a that opens to the anti-output-shaft-side AOS is formed at the tip end (radially inner end) of second radial oil passage 28.

[0042] The first radial oil passages 27 and the second radial oil passages 28 are formed such that a pair of circumferentially adjacent first radial oil passages 27 and a pair of circumferentially adjacent second radial oil passages 28 are alternately arranged in the circumferential direction. Note that such annular space 26, first radial oil passages 27, and second radial oil passages 28 are not formed inside the second oil plate 20′.

[0043] The first oil plate 20 is attached to the end of the AOS on the side opposite to the output shaft of the stator core 11 so that it is concentric with the stator core 11 and the positions of the teeth 23 in the circumferential direction coincide with the positions of the teeth 13 of the stator core 11. The second oil plate 20' is also attached to the end of the OS on the side opposite to the output shaft of the stator core 11 in the same manner as the first oil plate 20.

[0044] <Stator coil> The stator coil 17 is composed of a U-shaped coil wire with two parallel legs and a connecting portion connecting the two legs, and its surface is coated with an insulating material except for a portion. The stator coil 17 is attached to the stator core 11 and the first and second oil plates 20, 20' by inserting the two legs from the anti-output-shaft side AOS into a pair of adjacent slots 15, 25, for example. The tip of one leg of the stator coil 17 protruding from the slot of the second oil plate 20' toward the output-shaft side OS is connected to the tip of the other leg of the stator coil 17 protruding from the slot toward the output-shaft side OS by welding or the like.

[0045] As shown in Figure 3(b), the connecting portion of the U-shaped coil wire that protrudes from the slot 25 of the first oil plate 20 toward the anti-output-shaft side AOS forms the first coil end 17a. Similarly, the portion of the U-shaped coil wire that protrudes from the slot of the second oil plate 20' toward the output-shaft side OS and is connected by welding or the like forms the second coil end 17b. In this stator 10, current flows from a power source (not shown) to the stator coil 17 via the input terminal 14, and the stator coil 17 is the main heat source in the stator 10.

[0046] <Oil guide> The first oil guide 30 of the anti-output-shaft AOS and the second oil guide 30' of the output-shaft OS are both made of a non-magnetic material such as resin and are cylindrical. The first and second oil guides 30, 30' are concentric with the stator core 11 and are axially interposed between the stator core 11 and the motor housing, and between the stator core 11 and the first and second oil plates 20, 20'. This allows the first and second oil plates 20, 20' to be pressed into the stator core 11 and firmly attached to it.

[0047] 3(a), a recess is formed in the upper end of the first oil guide 30, and this recess serves as an oil guide portion 31 that guides oil to the oil inlet port 29 of the first oil plate 20. In addition, a notch is formed in the lower end of the first oil guide 30, and this notched portion serves as an oil outlet port 33 for discharging oil.

[0048] <Oil flow> In the stator 10 configured as described above, fresh oil after heat exchange in the heat exchanger 8 passes through the stator-side oil passage 80 and is supplied to the stator 10 (more specifically, to the oil guide portion 31 of the first oil guide 30) as shown by the thick arrow OF1A in Figures 1 and 4(c). The fresh oil supplied to the oil guide portion 31 is guided to the oil inlet port 29 of the first oil plate 20, and is supplied from the oil inlet port 29 to the annular space 26 as shown by the thick arrow in Figure 4(b).

[0049] The fresh oil supplied to the annular space 26 flows down within the annular space 26 while being divided into the first radial oil passage 27 and the second radial oil passage 28, as shown by the thin arrows in Fig. 4(b). As a result, the annular space 26 is filled with fresh oil, as shown by the thick arrows OF1B in Fig. 1 and Fig. 4(c).

[0050] Fresh oil filled in the annular space 26 is sprayed out from the through hole 27a formed at the tip of the first radial oil passage 27 and the through hole 28a formed at the tip of the second radial oil passage 28 to the AOS on the anti-output shaft side, as shown by the thick arrow OF1C in Figures 1 and 4(c), and is supplied to the first coil end 17a, for example, from the radial outside or to the radial center, depending on the position and inclination angle of the through holes 27a and 28a.

[0051] In this way, fresh oil that has passed through the heat exchanger 8 and the stator side oil passage 80 is supplied directly to the first coil end 17a without flowing inside the stator core 11, so that the first coil end 17a is efficiently cooled from the radial outside, center, etc. by the fresh oil.

[0052] -Rotor- Fig. 5 is a perspective view schematically showing rotor 40. As shown in Fig. 1, rotor 40 is concentric with stator 10 and is disposed inside stator core 11 with a gap (air gap) between its outer circumferential surface and teeth 13. As shown in Fig. 5, rotor 40 includes rotor core 41, rotor shaft 50, permanent magnets 101, 102, 103, 104, 105, and 106 embedded in magnet holes formed in rotor core 41, and first and second end plates 60 and 70 attached to both axial ends of rotor core 41, respectively.

[0053] <Rotor core> The rotor core 41 is a laminated body formed by stacking a predetermined number of annular magnetic thin plates formed into a predetermined shape in the axial direction, and is formed into a cylindrical shape with a center hole to which the rotor shaft 50 is fixed by shrink fitting. Although only four magnetic poles are shown in FIG. 5 , the rotor core 41 has six axially extending magnet holes for each magnetic pole so that the rotor 40 has eight magnetic poles and the angle of view φ of one magnetic pole along the circumferential direction as seen from the axis AC is 45 degrees, and permanent magnets 101, 102, ... are embedded in these six magnet holes. As shown in FIG. 5 , the rotor core 41 is configured as a so-called skewless rotor core, combining four laminated bodies 41A, 41B, 41C, 41D, each made of stacked magnetic thin plates, at a skew angle of 0 degrees. As a result, in this embodiment, the magnet holes and permanent magnets 101, 102, ... extend straight in the axial direction from the end of the anti-output-shaft-side AOS to the end of the output-shaft-side OS of the rotor core 41. Note that the magnetic thin plates can be made of an electromagnetic steel plate, which is a type of silicon steel plate.

[0054] Each magnetic pole is composed of a two-layer structure consisting of an outer embedded magnet section 100A including two permanent magnets 101, 102 arranged in a V-shape on the radially outer side, and an inner embedded magnet section 100B including four permanent magnets 103, 104, 105, 106 arranged in a U-shape on the radially inner side.

[0055] The outer embedded magnet portion 100A has one magnet hole, and the two permanent magnets 101, 102 are inserted into the magnet hole so as to form a V-shape, with the distance between them increasing radially outward and decreasing radially inward. The portion of the magnet hole that is not filled with the two permanent magnets 101, 102 remains as a gap (flux barrier) 42.

[0056] The inner embedded magnet portion 100B has four magnet holes. The permanent magnets 103 and 106 are inserted into the magnet holes so that the spacing between them increases radially outward and decreases radially inward. The permanent magnets 104 and 105 are inserted into the magnet holes, and the portions of the magnet holes not filled with the permanent magnets 104 and 105 remain as gaps 43 and 44.

[0057] <Rotor shaft> Fig. 6 is a diagram schematically showing the oil passages and oil flow in the rotor 40. Specifically, Fig. 6(a) is a perspective view showing the oil inlet passage 50a of the rotor shaft 50, Fig. 6(b) is a perspective view showing the oil passage formed in the first end plate 60, and Fig. 6(c) is a perspective view showing the oil flow in the entire rotor 40. The rotor shaft 50 has an oil inlet portion 51 and a shaft main body portion 57.

[0058] <Oil inlet> As shown in FIG. 6( a), the oil introduction portion 51 is formed in a shape in which a cylindrical small-diameter portion 52 and a cylindrical large-diameter portion 53 are concentrically connected in the axial direction via a stepped surface. An oil introduction hole 54 extending in the axial direction and communicating with the rotor-side oil passage 90 is formed through the oil introduction portion 51. A recess with a circular cross section is formed at the end of the output-shaft-side OS of the large-diameter portion 53 and communicates with the oil introduction hole 54. Furthermore, eight oil discharge grooves are formed at the end of the output-shaft-side OS of the large-diameter portion 53, extending radially outward from the recess at equal 45-degree intervals in the circumferential direction. The radially outer end of each oil discharge groove opens at the outer peripheral surface of the large-diameter portion 53.

[0059] <Shaft body> As shown in Fig. 6(a), the shaft main body 57 is formed in a cylindrical shape centered on an axis AC. A partition plate 58 is provided in the shaft main body 57 to divide the hollow portion 57a ​​in the axial direction. Eight oil discharge holes 59 are formed in the shaft main body 57, which extend radially outward at equal 45-degree intervals in the circumferential direction and penetrate the shaft main body 57.

[0060] <Oil inlet path> The rotor shaft 50 is constructed by fitting the large diameter portion 53 into the hollow portion 57a ​​of the shaft main body 57 so that the circumferential positions of the eight oil discharge grooves and the eight oil discharge holes 59 coincide, and then joining the two by welding or the like. When the oil inlet portion 51 and the shaft main body 57 are combined, the recesses and the oil discharge grooves are covered by the anti-output-shaft-side AOS surface of the partition plate 58, thereby forming the disk-shaped space 55 and the oil discharge path 56, as shown in FIG. 6(a). As a result, the oil inlet path 50a is formed, in which fresh oil that has flowed through the rotor-side oil path 90 flows through the oil inlet hole 54, fills the disk-shaped space 55, flows radially outward from the disk-shaped space 55 through the oil discharge path 56, and is then sent radially outward to the outside of the rotor shaft 50 through the oil discharge holes 59.

[0061] <End plate> The first and second end plates 60, 70 are annular aluminum plates having the same outer shapes as the inner and outer peripheral surfaces of the rotor core 41. The first end plate 60 is attached by welding or the like to the end of the AOS on the anti-output shaft side of the rotor core 41, and the second end plate 70 is attached by welding or the like to the end of the OS on the output shaft side of the rotor core 41. As shown in FIG. 1 , the first end plate 60 is disposed so as to overlap the first coil end 17a when viewed in the radial direction. Note that the second end plate 70 does not have any distinctive features, and therefore a detailed description thereof will be omitted.

[0062] As shown in FIG. 6(b), the first end plate 60 is formed with eight connecting passages 61 extending radially outward from its inner circumferential surface at equal 45-degree intervals in the circumferential direction. The first end plate 60 also has eight first diffusion oil passages 63 that communicate with the radially outer ends of the connecting passages 61 and extend radially outward beyond the connecting passages 61. Each first diffusion oil passage 63 opens at the outer circumferential surface of the first end plate 60 and is formed so that its cross-sectional area increases radially outward. When the rotor shaft 50 and the first end plate 60 are assembled so that the eight oil discharge holes 59 and the eight connecting passages 61 are aligned in the circumferential direction, the oil introduction passages 50a of the rotor shaft 50 communicate with the first diffusion oil passages 63 via the connecting passages 61, as shown in FIG. 6(b).

[0063] The connecting flow path 61 and the first diffusion oil path 63 may be formed, for example, using a sand mold for casting, or may be formed, for example, by configuring the first end plate 60 as two plates (not shown) that are divided into two in the axial direction, providing grooves or holes that become part of the oil path on the front and back surfaces of each plate, and combining these grooves or holes in the axial direction.

[0064] <Oil flow> In the rotor 40 configured as described above, fresh oil after heat exchange in the heat exchanger 8 passes through the rotor-side oil passage 90 and is supplied to the rotor 40 (more specifically, to the oil inlet hole 54 of the oil inlet portion 51) as shown by the thick arrows OF1D in Figures 1 and 6(c). The fresh oil supplied to the oil inlet hole 54 flows sequentially through the oil inlet passage 50a and is sent radially outward from the rotor shaft 50 through the oil discharge holes 59 as shown by the thick arrows OF1E in Figures 1 and 6(c).

[0065] Fresh oil discharged radially from oil discharge holes 59 then flows through connecting flow passage 61 to first diffusion oil passage 63, where it is thrown radially outward from the outer circumferential surface of first end plate 60 by centrifugal force and supplied to first coil end 17a from the radially inner side, as shown by the thick arrows OF1F in Figures 1 and 6(c). At this time, first diffusion oil passage 63 is formed so that the cross-sectional area increases radially outward, making it possible to prevent first diffusion oil passage 63 from being blocked by oil.

[0066] In this way, fresh oil that has passed through the heat exchanger 8 and the rotor-side oil passage 90 is supplied to the first coil end 17a from the radially inner side without flowing inside the rotor core 41, so that the first coil end 17a is efficiently cooled from the radially inner side by the fresh oil.

[0067] -effect- As described above, according to the motor cooling system S1 of this embodiment, fresh oil that has not been used to cool the stator core 11 or the rotor core 41 is simultaneously supplied to the first coil end 17a from the outside, center, inside, etc. in the radial direction, thereby enabling the first coil end 17a to be cooled efficiently.

[0068] Furthermore, by utilizing the first oil plate 20 attached to the end of the stator core 11 and the first end plate 60 attached to the end of the rotor core 41, it is possible to easily realize a configuration in which the first coil end 17a is cooled by fresh oil without the oil flowing inside the stator core 11 or the rotor core 41.

[0069] (Variation) This modified example differs from the first embodiment in that it cools not only the first coil ends 17a but also the second coil ends 17b. The following description will focus on the differences from the first embodiment.

[0070] -Cooling System- Fig. 7 is a longitudinal cross-sectional view showing a motor cooling system S1' according to this modified example. In this motor cooling system S1', fresh oil after heat exchange in heat exchanger 8 passes through stator-side oil passage 81 and is supplied not only to the end of stator 10 on the side opposite the output shaft (AOS) but also to the end of stator 10 on the side opposite the output shaft (OS).

[0071] - Stator - 7, in the stator 10 according to this modification, a plate identical to the first oil plate 20 (second oil plate 20) is attached to the end of the output shaft side OS of the stator core 11, instead of a second oil plate 20′. Specifically, the first and second oil plates 20 are attached to both ends of the stator core 11 in the axial direction so as to be symmetrical with respect to the stator core 11.

[0072] <Oil flow> In the stator 10 configured as described above, fresh oil is supplied to the first and second oil plates 20 through the stator-side oil passage 81, as indicated by thick arrows OF1A and OF1A' in Fig. 7. The fresh oil then fills the annular spaces 26 as indicated by thick arrows OF1B and OF1B' in Fig. 7, and is then ejected from the first oil plate 20 to the anti-output-shaft-side AOS as indicated by thick arrow OF1C in Fig. 7, and from the second oil plate 20 to the output-shaft-side OS as indicated by thick arrow OF1C' in Fig. 7, where it is supplied to the first and second coil ends 17a, 17b.

[0073] In this way, fresh oil that has passed through the stator side oil passage 81 is supplied directly to not only the first coil end 17a but also the second coil end 17b without flowing inside the stator core 11, so that the first and second coil ends 17a, 17b are efficiently cooled from the radial outside, center, etc. by the fresh oil.

[0074] -Rotor- 7, in the rotor 40 according to this modification, a second end plate 60 identical to the first end plate 60 is attached to the end of the output-shaft side OS of the rotor core 41, rather than a second end plate 70. Specifically, the first and second end plates 60 are attached to both axial ends of the rotor core 41 so as to be symmetrical across the rotor core 41. The second end plate 60 of the output-shaft side OS is disposed so as to overlap the second coil end 17b when viewed in the radial direction.

[0075] Furthermore, partition plate 58, which axially divides hollow portion 57a ​​of shaft main body 57, is formed with through holes 58a that axially pass through partition plate 58. Furthermore, eight oil discharge holes 59' are formed in shaft main body 57 at a portion in the axial direction that corresponds to second end plate 60. These holes 59' extend radially outward at equal 45-degree intervals in the circumferential direction and pass through shaft main body 57.

[0076] <Oil flow> In the rotor 40 configured as described above, fresh oil passes through the rotor-side oil passage 90 and is supplied to the oil inlet hole 54 of the oil introduction portion 51, as indicated by the thick arrow OF1D in Fig. 7. The fresh oil supplied to the oil inlet hole 54 is sent radially outward from the rotor shaft 50 through the oil discharge holes 59 of the anti-output-shaft-side AOS, as indicated by the thick arrow OF1E in Fig. 7, and also passes through the through-hole 58a and flows through the hollow portion 57a ​​of the shaft main body 57 to the output-shaft-side OS, as indicated by the thick arrow OF1D' in Fig. 7.

[0077] Fresh oil that has flowed through hollow portion 57a ​​of shaft main body 57 to the output-shaft-side OS is sent radially to the outside of rotor shaft 50 through oil discharge holes 59' in the output-shaft-side OS, as indicated by thick arrows OF1E' in Fig. 7. Fresh oil that has been sent radially from oil discharge holes 59, 59' in the anti-output-shaft-side AOS and the output-shaft-side OS flows into first diffusion oil passage 63 via connecting passage 61, as indicated by thick arrows OF1F and OF1F' in Fig. 7, and is thrown radially outward from the outer circumferential surfaces of first and second end plates 60 by centrifugal force, and is supplied to first and second coil ends 17a, 17b from the radially inner side.

[0078] In this way, fresh oil that has passed through the rotor-side oil passage 90 is supplied from the radially inner side not only to the first coil end 17a but also to the second coil end 17b without flowing inside the rotor core 41, so that the first and second coil ends 17a, 17b are efficiently cooled from the radially inner side by the fresh oil.

[0079] -effect- As described above, according to the motor cooling system S1' of this modified example, fresh oil that has not been used to cool the stator core 11 or the rotor core 41 is simultaneously supplied to the first and second coil ends 17a, 17b, thereby efficiently cooling the first and second coil ends 17a, 17b.

[0080] (Embodiment 2) This embodiment differs from the first embodiment in that it cools not only the first coil ends 17a but also the stator core 11 and the rotor core 41. The following description will focus on the differences from the first embodiment.

[0081] - Stator - Fig. 8 is a vertical cross-sectional view schematically showing the motor cooling system S2 according to this embodiment. Fig. 9 is a diagram schematically showing the stator 10. Fig. 9(a) is a cross-sectional view of the output shaft side OS surface of the first oil plate 120, Figs. 9(b) and 9(c) are cross-sectional views of the rotor core 41, and Fig. 9(d) is a perspective view showing the flow of oil in the stator 10.

[0082] <Oil plate> In addition to the first radial oil passage 27 and the second radial oil passage 28, as shown in FIG. 9(a), the inside of the first oil plate 120 is formed with a third radial oil passage 127 extending in the same direction as the slots 25 by recessing a portion defining the radially inner side of the annular space 26 radially inward. The third radial oil passages 127 are formed so that the number of third radial oil passages 127 corresponds to the number of slots 25 and are aligned in the circumferential direction. A through hole 127a that opens to the output-shaft-side OS is formed at the tip end (radially inner end) of the third radial oil passage 127. Note that, as in the first embodiment, on the surface of the counter-output-shaft-side AOS of the first oil plate 120, through holes 27a and 28a are formed at the tip end portions of the first and second radial oil passages 27 and 28, respectively.

[0083] The first oil plate 120 is attached to the end of the AOS on the anti-output shaft side of the stator core 11 so that it is concentric with the stator core 11 and the positions of the teeth 23 in the circumferential direction coincide with the positions of the teeth 13 of the stator core 11. When the first oil plate 120 is attached to the stator core 11 in this way, the axial oil passage 19 (19') formed in the stator core 11 communicates with the through hole 127a, as shown in FIG. 9(a).

[0084] <Stator core> As shown in Fig. 9(b), axial oil passages 19 are formed in the stator core 11 radially outside each slot 15, penetrating the stator core 11 over the entire axial length. Instead of separately forming such axial oil passages 19, the space between the slot 15 and the stator coil 17 inserted into the slot 15 may be used as the axial oil passage 19', as shown in Fig. 9(c).

[0085] <Oil flow> In the stator 10 configured as described above, fresh oil is supplied to the stator 10 (more specifically, to the oil guide portion 31 of the first oil guide 30) through the stator-side oil passage 80 as shown by the thick arrow OF2A in Figures 8 and 9(d). The fresh oil supplied to the oil guide portion 31 is guided to the oil inlet port 29 of the first oil plate 120, and is supplied from the oil inlet port 29 to the annular space 26 as shown by the thick arrow in Figure 9(a).

[0086] As shown by the thin arrows in Fig. 9(a), the fresh oil supplied to the annular space 26 flows down within the annular space 26 while being divided (distributed) into the first radial oil passage 27, the second radial oil passage 28, and the third radial oil passage 127. As a result, the annular space 26 is filled with fresh oil, as shown by the thick arrows OF2B in Fig. 8 and Fig. 9(d).

[0087] As in embodiment 1, a portion of the fresh oil filled in the annular space 26 is ejected from the through hole 27a formed at the tip of the first radial oil passage 27 and the through hole 28a formed at the tip of the second radial oil passage 28 to the AOS on the anti-output shaft side, as shown by the thick arrow OF2C in Figure 8, and is supplied to the first coil end 17a.

[0088] On the other hand, the remainder of the fresh oil filled in the annular space 26 is sprayed out from the through hole 127a formed at the tip of the third radial oil passage 127 to the output shaft side OS, and flows through the axial oil passage 19 (19') that penetrates the stator core 11 to the output shaft side OS, as shown by the thick arrow OF2D in Figures 8 and 9(d).

[0089] In this way, a portion of the fresh oil that has passed through the stator side oil passage 80 is supplied to the first coil end 17a, and the remaining portion of the fresh oil is supplied axially into the stator core 11, so that the inside of the stator core 11 is cooled by the fresh oil while maintaining the first coil end 17a in a cooled state.

[0090] In addition, the oil that flows through the axial oil passage 19 (19') and reaches the end of the output shaft side OS of the stator core 11 can be discharged to the outside of the stator core 11 through a discharge hole (not shown), for example, formed in the second oil plate 20'.

[0091] -Rotor- FIG. 10 is a diagram schematically illustrating the rotor 40. More specifically, FIG. 10(a) is a perspective view showing oil passages formed in the rotor 40, FIG. 10(b) is a perspective view showing the space formed within the first end plate 160, and FIG. 10(c) is a diagram illustrating the space formed within the first end plate 160. Note that in FIG. 10(c), the permanent magnets 104 and 105 are omitted for clarity. In addition, in the rotor 40 of this embodiment, the rotor shaft 50, rotor core 41, and second end plate 70 have the same configurations as those in the first embodiment.

[0092] <End plate> As shown in Fig. 8, the first end plate 160 is disposed so as to overlap the first coil end 17a in the radial direction, similar to the first end plate 60. Within the first end plate 160, as shown in Figs. 10(a) and 10(b), a chamber space 162 that is annular in the axial direction is formed concentrically with the axis AC. Furthermore, within the first end plate 160, eight connecting passages 161 are also formed that extend radially outward from the inner peripheral surface of the first end plate 160 at equal 45-degree intervals in the circumferential direction and connect (communicate) with the chamber space 162. The first end plate 160 is combined with the rotor shaft 50 so that the eight oil discharge holes 59 and the eight connecting passages 161 are aligned in the circumferential direction.

[0093] Furthermore, eight first diffusion oil passages 163 extending radially are formed within first end plate 160, on the AOS on the side opposite the output shaft from chamber space 162. Like first diffusion oil passage 63, each first diffusion oil passage 163 opens at the outer peripheral surface of first end plate 160 and is formed so that the cross-sectional area increases radially outward. However, unlike first diffusion oil passage 63, the radially inner end of each first diffusion oil passage 163 communicates with chamber space 162 via communication holes 164, as shown in FIG. 10(b).

[0094] The connecting flow path 161, chamber space 162 and first diffusion oil path 163 may be formed, for example, using a sand mold for casting, or may be formed, for example, by configuring the first end plate 160 as plates (not shown) divided into three in the axial direction, providing grooves or holes that become part of the oil path, etc. on the front and back surfaces of each plate, and combining these grooves or holes in the axial direction.

[0095] A plurality of grooves are formed in the surface of the output-shaft-side OS of the first end plate 160. When the surface of the output-shaft-side OS of the first end plate 160 is attached to the end surface of the anti-output-shaft-side AOS of the rotor core 41 by welding or the like as shown in FIG. 8, the grooves are covered with the end surface of the anti-output-shaft-side AOS of the rotor core 41. As shown in FIG. 10(c), eight first radial oil passages 166 extending radially are formed on the output-shaft-side OS of the rotor core 41, closer to the chamber space 162 than the chamber space 162. The radially inner end of each of the first radial oil passages 166 communicates with the chamber space 162 via a communication hole 165. The length of each of the first radial oil passages 166 is set so that the radially outer end communicates with the gap 42 of the magnet hole (the portion of the magnet hole not filled with the permanent magnets 101, 102).

[0096] Similarly, the grooves are covered by the end face of the AOS on the anti-output shaft side of rotor core 41, and sixteen second radial oil passages 168 are also formed, extending at an inclination in the circumferential direction as they move radially outward, on the OS closer to the output shaft than chamber space 162. The radially inner end of each second radial oil passage 168 communicates with chamber space 162 via communication holes 167. The length and inclination direction of each second radial oil passage 168 are set so that the radially outer end communicates with gaps 43, 44 of the magnet holes.

[0097] The first end plate 160 configured as described above is attached by welding or the like to the end face of the AOS on the anti-output shaft side of the rotor core 41 so that the radially outer end of the first radial oil passage 166 and the gap 42 of the magnet hole are aligned circumferentially, as shown in Figure 10(c).

[0098] <Oil flow> Figure 11 is a diagram that schematically illustrates the oil passages and oil flow in the rotor 40. More specifically, Figure 11(a) is a cross-sectional view showing the oil passages in the rotor core 41, and Figure 11(b) is a perspective view that illustrates the oil flow in the entire rotor 40. Note that in Figure 11(a), to make the drawing easier to see, hatching that indicates cross sections has been omitted, and oil is shown as blackened areas.

[0099] In the rotor 40 configured as described above, fresh oil passes through the rotor-side oil passage 90 and is supplied to the oil inlet hole 54 of the oil inlet portion 51, as indicated by the thick arrows OF2E in Figures 8 and 11(b). The fresh oil introduced into the oil inlet hole 54 flows sequentially through the oil inlet passage 50a and is then discharged radially to the outside of the rotor shaft 50 through the oil discharge holes 59, as indicated by the thick arrows OF2F in Figures 8 and 11(b). The fresh oil thus discharged to the outside of the rotor shaft 50 passes through the connecting passage 161 to the chamber space 162, and is filled into the chamber space 162, as indicated by the thick arrows OF2G in Figure 11(b).

[0100] The fresh oil filled in chamber space 162 is distributed to the first coil end 17a side and the rotor core 41 side. Specifically, as shown by the thick arrows OF2H in Figures 8 and 11(b), some of the fresh oil filled in chamber space 162 flows from chamber space 162 to first diffusion oil passage 163 via communication hole 164, and is thrown radially outward from the outer circumferential surface of first end plate 160 by centrifugal force, and is supplied to first coil end 17a from the radially inner side.

[0101] Meanwhile, the remainder of the fresh oil filled in the chamber space 162 flows from the chamber space 162 through the communication holes 165, 167 to the first radial oil passage 166 and the second radial oil passage 168, as shown by the thick arrows OF2I in Figures 8 and 11(b). The fresh oil that has passed through the first radial oil passage 166 flows into the gap 42, as shown in Figure 11(a), and the fresh oil that has passed through the second radial oil passage 168 flows into the gaps 43, 44. The fresh oil that has flowed into the gaps 42, 43, 44 then flows inside the rotor core 41 from the anti-output shaft side AOS to the output shaft side OS, as shown by the thick arrows OF2J in Figures 8 and 11(b).

[0102] In this way, a portion of the oil that has passed through the rotor side oil passage 90 is supplied to the first coil end 17a, and the remaining portion of the oil is supplied axially into the rotor core 41, so that the inside of the rotor core 41 is cooled by fresh oil while maintaining a state in which the first coil end 17a is cooled from the radially inside.

[0103] In addition, oil that flows through gaps 42, 43, and 44 and reaches the end of the output shaft side OS of rotor core 41 can be discharged to the outside of rotor core 41 through a discharge hole (not shown), for example, formed in second end plate 70.

[0104] -effect- As described above, according to the motor cooling system S2 of this embodiment, fresh oil is not only supplied to the first coil end 17a, but also simultaneously supplied to the stator core 11 and the rotor core 41, thereby efficiently cooling each part of the motor 1, including the first coil end 17a.

[0105] Furthermore, fresh oil supplied axially into the stator core 11 and the rotor core 41 first passes through the annular annular space 26 formed in the first oil plate 120 and the annular chamber space 162 formed in the first end plate 160 before being distributed within the stator core 11 and the rotor core 41. This makes it possible to evenly supply fresh oil to, for example, the axial oil passage 19 (19') formed in the stator core 11 and the gaps 42, 43, 44 formed in the rotor core 41.

[0106] In particular, in the rotor 40, the first diffusion oil passage 163 is formed so that its cross-sectional area increases as it moves radially outward, which prevents the first diffusion oil passage 163 from becoming blocked by oil. This makes it possible to prevent negative pressure from being generated within the first diffusion oil passage 163, which in turn prevents the uniformity of the oil within the chamber space 162 from being impaired.

[0107] Furthermore, by adopting an axial oil passage 19' in which oil flows axially within the stator core 11 through between the slots 15 and the stator coil 17, the stator coil 17 can be directly cooled, and since the oil flows axially within the rotor core 41 through the gaps 42, 43, 44 of the magnet holes in which the permanent magnets 101, 102, 103, 106 are embedded, the permanent magnets 101, 102, ... can be directly cooled by fresh oil.

[0108] In addition, as described above, since the rotor core 41 is so-called skewless, the flow resistance of the oil flowing through the gaps 42, 43, 44 can be reduced, thereby allowing the permanent magnets 101, 102, ... to be cooled even more efficiently.

[0109] (Embodiment 3) This embodiment differs from the first and second embodiments in that the second coil ends 17b are cooled. The following description will focus on the differences from the first and second embodiments.

[0110] -Cooling System- 12 is a longitudinal cross-sectional view schematically showing a motor cooling system S3 according to this embodiment. In this motor cooling system S3, fresh oil is supplied to the ends of the anti-output-shaft side AOS and the output-shaft side OS of the stator 10 through a stator-side oil passage 81, as shown in FIG.

[0111] - Stator - In the stator 10 of this embodiment, the stator core 11 has the same configuration as that of the second embodiment.

[0112] <Oil plate> Fig. 13 is a diagram schematically showing oil plate 220 and second end plate 170. More specifically, Fig. 13(a) is a cross-sectional view of oil plate 220 looking at the surface facing stator core 11, and Fig. 13(b) is a perspective view showing second end plate 170. In this embodiment, the same oil guides 30 are attached to both the anti-output-shaft-side AOS and the output-shaft-side OS ends of stator core 11 so as to be symmetrical across stator core 11 (see Fig. 14).

[0113] 12, in this embodiment, substantially identical oil plates 220 are attached to both ends of the anti-output-shaft-side AOS and the output-shaft-side OS of the stator core 11. The only difference between the first oil plate 220 of the anti-output-shaft-side AOS and the second oil plate 220 of the output-shaft-side OS is that the positions of the through holes 127a and 227a are alternately shifted in the circumferential direction, and therefore the following description will be limited to the first oil plate 220 of the anti-output-shaft-side AOS.

[0114] Similar to the first oil plate 120 of the second embodiment, the first oil plate 220 has first radial oil passages 27, second radial oil passages 28, and third radial oil passages 127 formed therein, but the number of third radial oil passages 127 is half the number of third radial oil passages 127 in the first oil plate 120. More specifically, in the first oil plate 220, a pair of slots 25 that are adjacent to each other in the circumferential direction and have third radial oil passages 127 formed on the radially outer side, and a pair of slots 25 that are adjacent to each other in the circumferential direction and do not have third radial oil passages 127 formed on the radially outer side, are formed alternately in the circumferential direction.

[0115] Thus, through holes 227a penetrating the first oil plate 220 are formed on the radially outer sides of a pair of slots 25 on which the third radial oil passage 127 is not formed in the radially outer side. Because the through holes 227a do not communicate with the annular space 26, fresh oil supplied from the oil inlet 29 of the first oil plate 220 to the annular space 26 does not pass through the through holes 227a. Note that, as in the first and second embodiments, on the anti-output-shaft-side AOS surface of the oil plate 120, through holes 27a, 28a are formed at the tip portions of the first and second radial oil passages 27, 28, respectively.

[0116] The first oil plate 220 is attached to the end of the AOS on the anti-output shaft side of the stator core 11 so that it is concentric with the stator core 11 and the positions of the teeth 23 in the circumferential direction coincide with the positions of the teeth 13 of the stator core 11. When the first oil plate 220 is attached to the stator core 11 in this way, the axial oil passage 19 (19') formed in the stator core 11 communicates not only with the through hole 127a but also with the through hole 227a.

[0117] <Oil flow> Fig. 14 is a perspective view that schematically illustrates the flow of oil in the stator 10. Fig. 14(a) shows the flow of oil from the first oil plate 220 to the AOS on the counter-output shaft side, Fig. 14(b) shows the flow of oil from the first oil plate 220 to the OS on the output shaft side, Fig. 14(c) shows the flow of oil from the second oil plate 220 to the OS on the output shaft side, and Fig. 14(d) shows the flow of oil from the second oil plate 220 to the AOS on the counter-output shaft side.

[0118] In the stator 10 configured as described above, fresh oil that has passed through the stator-side oil passage 81 is supplied to the oil guide portion 31 of the first oil guide 30, as shown by the thick arrows OF3A in Figure 12 and Figures 14(a) and (b). At this time, fresh oil that has passed through the stator-side oil passage 81 on the output shaft side OS is also supplied to the oil guide portion 31 of the second oil guide 30, as shown by the thick arrows OF3A' in Figure 12 and Figures 14(c) and (d).

[0119] Fresh oil supplied to the oil guide portion 31 is guided to the oil inlet ports 29 of the first and second oil plates 220 and is supplied from the oil inlet ports 29 to the annular space 26, as shown by the thick arrows in Fig. 13(a). The fresh oil supplied to the annular space 26 flows down within the annular space 26 while being diverted (distributed) to the first radial oil passage 27, the second radial oil passage 28, and the third radial oil passage 127, as shown by the thin arrows in Fig. 13(a). As a result, the annular space 26 in the first and second oil plates 220 is filled with fresh oil, as shown by the thick arrows OF3B in Fig. 12 and Figs. 14(a) and (b) and the thick arrow OF3B' in Fig. 12 and Figs. 14(c) and (d).

[0120] In the first oil plate 220, some of the fresh oil filled in the annular space 26 is ejected from the through holes 27a formed at the tip ends of the first radial oil passages 27 and the through holes 28a formed at the tip ends of the second radial oil passages 28 to the anti-output-shaft-side AOS, as shown by the thick arrows OF3C in Figures 12 and 14(a), and is supplied to the first coil end 17a. At this time, in the second oil plate 220, some of the fresh oil filled in the annular space 26 is ejected from the through holes 27a, 28a to the output-shaft-side OS, as shown by the thick arrows OF3C' in Figures 12 and 14(c), and is supplied to the second coil end 17b.

[0121] In the first oil plate 220, the remainder of the fresh oil filling the annular space 26 is ejected from the through hole 127a formed at the tip of the third radial oil passage 127 to the output-shaft-side OS, and flows through the axial oil passage 19 (19') penetrating the stator core 11 to the output-shaft-side OS as shown by the thick arrow OF3D in Figures 12 and 14(b). At this time, in the second oil plate 220, the remainder of the fresh oil filling the annular space 26 is ejected from the through hole 127a formed at the tip of the third radial oil passage 127 to the non-output-shaft-side AOS, and flows through the axial oil passage 19 (19') penetrating the stator core 11 to the non-output-shaft-side AOS as shown by the thick arrow OF3D' in Figures 12 and 14(d).

[0122] In the first oil plate 220, as indicated by the thick arrow OF3D' in Figures 12 and 14(d), the oil that has flowed through the axial oil passage 19 (19') to the anti-output-shaft-side AOS passes through the through-hole 227a and is supplied to the first coil end 17a. At this time, in the second oil plate 220, as indicated by the thick arrow OF3D in Figures 12 and 14(b), the oil that has flowed through the axial oil passage 19 (19') to the output-shaft-side OS passes through the through-hole 227a and is supplied to the second coil end 17b.

[0123] In this way, a portion of the fresh oil that has passed through the stator side oil passage 81 is supplied to the first and second coil ends 17a, 17b, and the remainder of the fresh oil is supplied axially into the stator core 11, so that the first and second coil ends 17a, 17b are efficiently cooled and the inside of the stator core 11 is efficiently cooled by the fresh oil.

[0124] The oil supplied to the first and second coil ends 17a, 17b is discharged from the oil discharge ports 33 of the first and second oil guides 30 to the outside of the stator 10 (to the bottom of the motor housing).

[0125] -Rotor- In the rotor 40 of this embodiment, the rotor shaft 50, the first end plate 160, and the rotor core 41 have the same configuration as in the second embodiment.

[0126] <End plate> 15A and 15B are diagrams schematically showing oil passages and oil flow in rotor 40. More specifically, Fig. 15A is a perspective view showing oil passages formed in rotor 40, and Fig. 15B is a perspective view showing oil flow in rotor 40.

[0127] As shown in FIG. 13(b), the second end plate 170 is formed with eight outer holes 171, each with a circular cross section, at equal 45-degree intervals in the circumferential direction. The outer holes 171 are recessed into the output-shaft-side AOS of the second end plate 170 at the counter-output-shaft side OS. The radial positions of these outer holes 171 correspond to the eight gaps 42. The second end plate 170 also has sixteen inner holes 173, each with a larger diameter than the outer holes 171, formed by recessing the counter-output-shaft-side AOS of the second end plate 170 at radially inner positions than the outer holes 171 toward the output-shaft-side OS. The radial positions of these inner holes 173 correspond to the sixteen gaps 43, 44.

[0128] Furthermore, as shown in FIG. 13(b), eight second short diffusion oil passages 172 extending radially are formed in the second end plate 170. The radially inner end of each second short diffusion oil passage 172 communicates with the outer hole 171, opens at the outer peripheral surface of the second end plate 170, and is formed so that the cross-sectional area increases radially outward. Similarly, sixteen second long diffusion oil passages 174 extending radially are formed in the second end plate 170. Like the second short diffusion oil passages 172, each second long diffusion oil passage 174 communicates with the inner hole 173, opens at the outer peripheral surface of the second end plate 170, and is formed so that the cross-sectional area increases radially outward.

[0129] When the surface of the AOS on the anti-output shaft side of the second end plate 170 is attached by welding or the like to the end face of the OS on the output shaft side of the rotor core 41 so that the outer hole 171 and the gap 42 (the inner hole 173 and the gaps 43, 44) are aligned circumferentially, the second short diffusion oil passage 172 and the gap 42 are connected via the outer hole 171, and the second long diffusion oil passage 174 and the gaps 43, 44 are connected via the inner hole 173, as shown in Figure 15(a).

[0130] The outer hole 171, the second short diffusion oil passage 172, the inner hole 173 and the second long diffusion oil passage 174 may be formed, for example, using a sand mold for casting, or may be formed, for example, by configuring the second end plate 170 as two plates (not shown) that are divided into two in the axial direction, providing grooves or holes that become part of the oil passages on the front and back surfaces of each plate, and combining these grooves or holes in the axial direction.

[0131] <Oil flow> In the rotor 40 configured as described above, the flow of oil from the rotor side oil passage 90 to the end of the output shaft side OS of the rotor core 41, specifically, the flow of oil to the thick arrows OF3E, OF3F, OF3G, OF3H, OF3I, and OF3J in Figures 12 and 15(b), is the same as the flow of oil to the thick arrows OF2E to OF2J in Figures 8 and 11(b), so its explanation will be omitted.

[0132] The oil that flows through gaps 42, 43, and 44 and reaches the end of the output shaft side OS of rotor core 41 reaches the second short diffusion oil passage 172 and the second long diffusion oil passage 174 via outer hole 171 and inner hole 173, respectively, as shown by the thick arrows OF3K in Figures 12 and 15(b), and is thrown radially outward from the outer peripheral surface of second end plate 170 by centrifugal force through these second short diffusion oil passage 172 and second long diffusion oil passage 174, and is supplied radially inward to second coil end 17b.

[0133] -effect- As described above, according to the motor cooling system S3 of this embodiment, fresh oil that has passed through the stator side oil passage 81 is supplied to the second coil end 17b, so that the second coil end 17b can also be cooled by the fresh oil.

[0134] Furthermore, because the oil supplied into rotor core 41 is supplied to second coil ends 17b from the radially inner side, it is possible to cool not only first coil ends 17a but also second coil ends 17b from the radially inner side. Unlike first coil ends 17a, second coil ends 17b are supplied with oil that has cooled rotor core 41 and the like (that has been heated to a certain extent). However, because the number of second short diffusion oil passages 172 and second long diffusion oil passages 174 (24) is set to be greater than the number of first diffusion oil passages 163 (8), in other words, the amount of oil supplied to second coil ends 17b is relatively greater, and second coil ends 17b can also be cooled efficiently.

[0135] In this way, fresh oil is not only supplied to the first coil end 17a, the stator core 11, and the rotor core 41 simultaneously, but also to the second coil end 17b, allowing each part of the motor 1, including the first coil end 17a, to be cooled efficiently over a wider area.

[0136] (Other embodiments) The present invention is not limited to the embodiments, and can be implemented in various other forms without departing from the spirit or main characteristics thereof.

[0137] In each of the above embodiments, the rotor core 41 is so-called skewless. However, this is not limited to this. For example, the present invention may be applied to a rotor core 41' having a skew angle θ, which is formed by combining four laminates 41A', 41B', 41C', and 41D', each of which is made by stacking a predetermined number of magnetic thin plates in the axial direction, with each laminate being shifted by an angle θ, as shown in Figure 16.

[0138] Furthermore, in each of the above embodiments, the through holes 27a, 28a extending straight in the axial direction are exemplified, but this is not limited to this. For example, the through holes may be formed so that they extend at an angle radially inward as they go axially outward.

[0139] Furthermore, in the above embodiment 1, the present invention is applied to a synchronous motor in which permanent magnets 101, 102, ... are embedded in the rotor core 41, but this is not limiting, and the present invention may also be applied to an asynchronous motor in which permanent magnets are not embedded in the rotor core.

[0140] Furthermore, in the second and third embodiments, the permanent magnets 101, 102, 103, and 106 are the targets to be cooled, but this is not limitative, and the number of radial oil paths may be increased so that the permanent magnets 104 and 105 are also cooled.

[0141] As such, the above-described embodiments are merely examples in all respects and should not be interpreted as limiting. Furthermore, all modifications and changes within the scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0142] According to the present invention, the coil ends of the stator coil can be cooled efficiently, and therefore it is extremely useful when applied to a motor cooling system that supplies cooling oil to each part of the motor. [Explanation of symbols]

[0143] 1 motor 8 Heat exchanger (cooling means) 10 Stator 11 Stator core 15 slots 17 Stator coil 17a First coil end 17b Second coil end 20,120,220 First oil plate 26 Annular space (circular space) 40 rotors 41,41' rotor core 42,43,44 Air gap (magnet hole) 60,160 First end plate 170 Second end plate 80,81 Stator side oil passage 90 Rotor side oil passage 162 Chamber space (annular space) S1, S2, S3 motor cooling system 101~106 Permanent magnets

Claims

1. A motor cooling system that supplies cooling oil to each part of a motor, a cooling means for cooling the oil; a stator having a cylindrical stator core on which a stator coil is mounted; a rotor having a cylindrical rotor core disposed inside the stator core; a stator-side oil passage capable of supplying the oil that has passed through the cooling means to the stator; a rotor-side oil passage capable of supplying the oil that has passed through the cooling means to the rotor, The stator is configured such that at least a portion of the oil that has passed through the stator-side oil passage is supplied to at least one coil end in the axial direction of the stator coil without flowing through the stator core, A motor cooling system characterized in that the rotor is configured so that at least a portion of the oil that has passed through the rotor-side oil passage is supplied from the radially inner side to at least one coil end on one axial side without flowing within the rotor core.

2. 2. The motor cooling system according to claim 1, the stator is configured such that a portion of the oil that has passed through the stator-side oil passage is supplied to the coil end on one side in the axial direction, and at least a portion of the remaining oil is supplied axially into the stator core, A motor cooling system characterized in that the rotor is configured so that a portion of the oil that has passed through the rotor-side oil passage is supplied to the coil end on one side in the axial direction, and the remainder of the oil is supplied axially into the rotor core.

3. 3. The motor cooling system according to claim 2, the stator is configured such that a portion of the remaining oil that has passed through the stator-side oil passage is supplied into the stator core, and another portion of the remaining oil is supplied to the coil end on the other axial side without flowing through the stator core, The rotor is configured such that oil supplied into the rotor core reaches the other axial end of the rotor core and is then supplied from the radially inner side to the coil end on the other axial side.

4. 3. The motor cooling system according to claim 2, the stator is configured such that oil that has passed through the stator-side oil passage passes through an annular space formed concentrically with the stator core in an oil plate attached to one end of the stator core in the axial direction, and is distributed to the coil end on the one axial side and within the stator core, The rotor is configured such that oil passing through the rotor-side oil passage passes through an annular space formed concentrically with the rotor core within an end plate attached to one axial end of the rotor core, and is distributed to the coil end on one axial side and within the rotor core.

5. 3. The motor cooling system according to claim 2, the rotor core has a plurality of axially extending magnet holes in which permanent magnets are embedded, the stator is configured such that oil supplied into the stator core flows in the axial direction through slots formed in the stator core and between the stator coils inserted into the slots; A motor cooling system characterized in that the rotor is configured so that oil supplied into the rotor core flows axially through the magnet holes.

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