Motor Cooling System

Abstract

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. The system 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 capable of supplying oil that has passed through the heat exchanger to the stator 10 and the rotor 40. The stator 10 is configured so 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 so 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.

Description

[Technical field]

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

[0002] As electric vehicles become more widespread, there is a demand for the motors that drive them to be easier to install and more productive, easier to deploy in a wide range of vehicle models, and cheaper to manufacture. To achieve these goals, there is a demand to reduce the size of the motor while maintaining its output, in other words, to increase the output density of the motor.

[0003] In order to increase the output density of a motor, it is unavoidable to increase the density of the current flowing through the stator coil, but increasing the current density in a motor can lead to a decrease in motor output, as, for example, the stator core, stator coil, rotor core, and (in the case of a synchronous motor) permanent magnets become hot. In particular, the coil ends of the stator coil protruding from both axial ends of the stator core are one of the areas that require high cooling, as it is difficult for refrigerants to reach them and the coil coating (insulating material) may melt if they become hot.

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

[0005] [Patent Document 1] JP 2019-146387 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the case of the above-mentioned Patent Document 1, the refrigerant that has circulated inside the rotor, in other words, the inside of the rotor is cooled, and the refrigerant that has been heated to a certain extent is then applied to the coil ends. Depending on the operating conditions, however, the coil ends may not be sufficiently cooled, and in this respect, there is room for improvement in the case of Patent Document 1.

[0007] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a motor cooling system capable of efficiently cooling the coil ends of a stator coil. [Means for solving the problem]

[0008] In order to achieve the above object, the motor cooling system of the present invention is configured to supply 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] This motor cooling system includes 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 the oil that has passed through the cooling means to the stator, and a rotor-side oil passage capable of supplying the oil that has passed through the cooling means to the rotor, and the stator cools the oil that has passed through the stator-side oil passage. One The department, The oil 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. The current does not flow through the stator core, but through the stator coil. Axis Supplied to the coil end on one side At the same time, at least a portion of the remaining oil is supplied axially into the stator core through the annular space.The rotor is configured so that the oil passing through the rotor-side oil passage One The department, Through an annular space formed concentrically with the rotor core in an end plate attached to one axial end of the rotor core, Without flowing through the rotor core 、 A supply is supplied from the radially inner side to the coil end on one axial side. At the same time, the remainder of the oil is supplied axially into the rotor core through the annular space. The present invention is characterized in that it is configured as follows.

[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 has passed through the rotor side oil passage is supplied to at least one coil end without flowing inside the rotor core, so that the coil end can be cooled from the radially inner side (hereinafter simply referred to as the "inside") by the fresh oil.

[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 simultaneously, thereby making it possible to efficiently cool the coil ends.

[0015] Also A portion of the oil that has passed through the stator side oil passage is supplied to the coil end on one side, and at least a portion of the remaining oil is supplied axially into the stator core, so that the coil end on one side can be maintained in a state where it is cooled by fresh oil, while the inside of the stator core can also be cooled by fresh oil.

[0016] Furthermore, a portion of the oil that has passed through the rotor side oil passage is supplied to the coil end on one side, and the remaining oil is supplied axially into the rotor core, so that the coil end on one side can be 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 not only supplied to the coil ends on one side, but also simultaneously supplied to the stator core and the rotor core, thereby efficiently cooling each part of the motor, including the coil ends. In addition, by using an oil plate attached to one axial end of the stator core or an end plate attached to one axial end of the rotor core, a configuration can be easily realized in which the coil ends are cooled by fresh oil without flowing inside the stator core or rotor core. Furthermore, fresh oil supplied axially into the stator core and rotor core first passes through the annular space formed in the oil plate or end plate, and then is 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. In this way, fresh oil is not only supplied to the coil ends on one side, but is also supplied evenly within the stator core and rotor core, making it possible to more efficiently cool each part of the motor, including the coil ends.

[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 of the rotor core on the other axial side, 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 from the inside to the coil end on the other side, 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 is used after cooling the inside of the rotor core.

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

[0026] Furthermore, in the motor cooling system, the rotor core may be formed with a plurality of axially extending magnet holes into which permanent magnets are embedded, the stator may be configured so that oil supplied into the stator core flows in the axial direction 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 in the axial direction through the magnet holes.

[0027] With this configuration, oil flows axially through the stator core between the slots and the stator coil, and also flows axially through the rotor core through the magnet holes in which the permanent magnets are embedded, so that the stator coil and permanent magnets can be directly cooled by fresh oil, thereby making it possible to more reliably and efficiently cool each part of the motor, including the coil ends. Effect of the Invention

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

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

[0030] Hereinafter, an embodiment 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) - Overview of the motor cooling system - FIG. 1 is a vertical cross-sectional view showing a schematic view of a main part of a motor cooling system S1 according to this embodiment. FIG. 2 is a block diagram showing a schematic view of an example of a cooling system S in an electric vehicle. This motor cooling system S1 constitutes a part of the cooling system S in an electric vehicle shown in FIG. 2, and as shown in FIG. 1, supplies oil for cooling to a first coil end (each part of the motor 1) 17a of a stator coil 17 (see FIG. 3). The motor cooling system S1 includes a heat exchanger (cooling means) 8 for cooling oil, a motor 1 having a stator 10 and a rotor 40, a stator-side oil passage 80 capable of supplying the oil that has passed through the heat exchanger 8 to the stator 10, and a rotor-side oil passage 90 capable of supplying 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, and a heat exchanger 8 is 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 cooling water circulates, and an inverter 5, a radiator 6, and a water pump 7 for circulating the cooling water, 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 cooling water, and the heat absorbed by the cooling water is dissipated to the outside by the radiator 6, thereby maintaining the cooling water 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, which are each provided on the circulation path 4. In this motor cooling system S1, heat generated in the motor 1 is absorbed by the oil, and the oil that has absorbed the heat accumulates at the bottom of a motor housing (not shown) and then returns to the circulation path 4. Thus, 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, by using the cooling system S configured as described above, oil (also referred to as "fresh oil" for convenience) maintained at a relatively low temperature is sent at an appropriate ratio 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 showing a schematic of 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 for ease of viewing. As shown in Fig. 3, the stator 10 includes a cylindrical stator core 11, a 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 has a cylindrical yoke 12 and teeth 13 arranged in the circumferential direction at intervals, each of which protrudes radially inward from the inner peripheral surface of the yoke 12. In this manner, the teeth 13 are arranged in the circumferential direction at intervals, and thus, a plurality of slots 15 that are partitioned (defined) by adjacent teeth 13 and open radially inward are formed in the stator core 11.

[0038] <Oil plate> FIG. 4 is a diagram showing 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 the 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 opposite side of the axial output shaft (hereinafter also simply referred to as the "opposite side of the output shaft AOS") and the second oil plate 20' on the OS on the output shaft side (hereinafter also simply referred to as the "output shaft side OS") in the axial direction are both made of a non-magnetic material such as resin, are formed in 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 (for convenience, referred to as the "yoke 22"), a portion corresponding to the teeth 13 (for convenience, referred to as the "teeth 23"), and a portion corresponding to the slots 15 (for convenience, referred to as the "slots 25"). 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 (b). More specifically, inside the first oil plate 20, an annular space 26 is formed concentrically with the first oil plate 20, the radially outer side of which is defined by an annular outer peripheral wall portion 21. The upper end portion of the outer peripheral wall portion 21 is cut out, and this cut out portion serves as an oil inlet 29 for introducing oil into the annular space 26.

[0040] Additionally, inside first oil plate 20, a portion defining the radially inner side of annular space 26 is recessed radially inward to form a first radial oil passage 27 extending in the same direction as teeth 23. A through hole 27a opening 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 defining the radially inner side of annular space 26 is recessed radially inward shallower than first radial oil passage 27 to form second radial oil passage 28 extending in the same direction as teeth 23. A through hole 28a opening 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 an 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 an end of the OS on the output shaft side of the stator core 11 in a similar manner to the first oil plate 20.

[0044] <Stator coil> The stator coil 17 is made of a U-shaped coil wire having two parallel legs and a connecting part connecting the two legs, and its surface is covered with an insulating material except for a part. 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. Then, the tip of the leg of one stator coil 17 protruding from the slot of the second oil plate 20' to the output shaft side OS is connected to the tip of the leg of the other stator coil 17 protruding from the slot to the output shaft side OS by welding or the like.

[0045] As shown in Fig. 3(b), the connecting portion of the U-shaped coil wire protruding from the slot 25 of the first oil plate 20 to the AOS on the anti-output shaft side constitutes the first coil end 17a. Similarly, the portion of the U-shaped coil wire protruding from the slot of the second oil plate 20' to the OS on the output shaft side and connected by welding or the like constitutes 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 AOS on the counter-output shaft side and the second oil guide 30' of the OS on the output shaft side are both made of a non-magnetic material such as resin and are formed into a cylindrical shape. The first and second oil guides 30, 30' are concentric with the stator core 11 and are interposed in the axial direction between the stator core 11 and the motor housing, as well as 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 side and firmly attached to the stator core 11.

[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 the oil.

[0048] <Oil flow> In the stator 10 configured as above, fresh oil after heat exchange in the heat exchanger 8 is supplied to the stator 10 (more specifically, the oil guide portion 31 of the first oil guide 30) through the stator-side oil passage 80 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 in the annular space 26 while being branched 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 anti-output shaft side AOS, 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 positions and inclination angles of the through holes 27a, 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, the center, etc. by the fresh oil.

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

[0053] <Rotor core> The rotor core 41 is a laminated body in which a predetermined number of annular magnetic thin plates formed into a predetermined shape are stacked in the axial direction, and is formed in a cylindrical shape having a central 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 magnet holes extending in the axial direction for each magnetic pole so that the number of magnetic poles of the rotor 40 is eight and the prospective angle 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 the six magnet holes. As shown in Fig. 5, the rotor core 41 is configured as a so-called skewless rotor core in which four laminated bodies 41A, 41B, 41C, 41D, each of which is made of stacked magnetic thin plates, are combined with a skew angle of 0 degrees. As a result, in this embodiment, the magnet holes and the permanent magnets 101, 102, ... extend straight in the axial direction from the end of the AOS on the counter-output shaft side to the end of the OS on the output shaft side of the rotor core 41. Note that the material for the magnetic thin plate can be 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 in which the distance between them increases radially outward and decreases 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 distance between them increases toward the radially outward direction and decreases toward the radially inward direction. The permanent magnets 104 and 105 are inserted into the magnet holes, and the portions of the magnet holes that are not filled with the permanent magnets 104 and 105 remain as gaps 43 and 44.

[0057] <Rotor shaft> Fig. 6 is a diagram showing a schematic of the oil passages and the flow of oil in the rotor 40. Specifically, Fig. 6(a) is a perspective view showing the oil introduction 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 flow of oil in the entire rotor 40. The rotor shaft 50 has an oil introduction portion 51 and a shaft main body portion 57.

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

[0059] <Shaft body> As shown in Fig. 6(a), the shaft body 57 is formed in a cylindrical shape centered on the axis AC. The shaft body 57 is provided with a partition plate 58 that divides the hollow portion 57a ​​in the axial direction. The shaft body 57 is also formed with eight oil drain holes 59 that extend radially outward at equal intervals of 45 degrees in the circumferential direction and penetrate the shaft body 57.

[0060] <Oil inlet passage> The rotor shaft 50 is constructed by fitting the large diameter portion 53 into the hollow portion 57a ​​of the shaft body 57 so that the circumferential positions of the eight oil discharge grooves and the eight oil discharge holes 59 coincide with each other, and then joining the two by welding or the like. When the oil introduction portion 51 and the shaft body 57 are combined, the recess and the oil discharge groove are covered by the surface of the AOS on the opposite side of the output shaft of the partition plate 58, and a disk-shaped space 55 and an oil discharge passage 56 are formed, as shown in FIG. 6(a). As a result, the oil introduction passage 50a is formed in which fresh oil that has flowed through the rotor side oil passage 90 flows through the oil introduction hole 54, fills the disk-shaped space 55, flows from the disk-shaped space 55 through the oil discharge passage 56 to the radially outward side, and is then sent out radially to the outside of the rotor shaft 50 through the oil discharge hole 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 circumferential surfaces of the rotor core 41. The first end plate 60 is attached to an end of the AOS on the anti-output shaft side of the rotor core 41, and the second end plate 70 is attached to an end of the OS on the output shaft side of the rotor core 41 by welding or the like. 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. Since the second end plate 70 does not have any distinctive features, 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 peripheral surface at equal intervals of 45 degrees in the circumferential direction. Also, the first end plate 60 is formed with eight first diffusion oil passages 63 that communicate with the radially outer ends of the connecting passages 61 and extend radially outward from the connecting passages 61. Each first diffusion oil passage 63 opens on the outer peripheral surface of the first end plate 60 and is formed so that the cross-sectional area increases as it goes radially outward. Then, when the rotor shaft 50 and the first end plate 60 are combined so that the eight oil discharge holes 59 and the eight connecting passages 61 coincide in the circumferential direction, the oil introduction passages 50a of the rotor shaft 50 and the first diffusion oil passages 63 communicate with each other via the connecting passages 61, as shown in FIG. 6(b).

[0063] The connecting flow passage 61 and the first diffusion oil passage 63 may be formed, for example, by using a sand mold for casting, or by forming the first end plate 60 into two plates (not shown) that are divided into two in the axial direction, and providing grooves or holes that become part of the oil passage 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 is supplied to the rotor 40 (more specifically, the oil inlet hole 54 of the oil inlet portion 51) through the rotor-side oil passage 90, as shown by the thick arrow 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 out radially to the outside of the rotor shaft 50 through the oil discharge holes 59, as shown by the thick arrow 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, and as shown by thick arrow OF1F in Figures 1 and 6(c), is thrown radially outward from the outer circumferential surface of first end plate 60 by centrifugal force, and is supplied to first coil end 17a from the radially inner side. At this time, first diffusion oil passage 63 is formed so that the cross-sectional area increases as it goes 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 radial outside, center, inside, etc., so that the first coil end 17a can be efficiently cooled.

[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, a configuration can be easily realized 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] (Modification) This modified example differs from the first embodiment in that not only the first coil ends 17a but also the second coil ends 17b are cooled. The following description will focus on the differences from the first embodiment.

[0070] -Cooling System- Fig. 7 is a vertical 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 is supplied through stator-side oil passage 81 to not only the end of the AOS on the side opposite to the output shaft of stator 10 but also the end of the OS on the output shaft side.

[0071] -Stator- 7, in the stator 10 according to this modification, instead of a second oil plate 20', 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. 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 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. Then, the fresh oil is filled into the annular space 26, as indicated by thick arrows OF1B and OF1B' in Fig. 7, and 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 ejected from the second oil plate 20 to the output-shaft side OS, as indicated by thick arrow OF1C' in Fig. 7, to be 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 with respect to 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, a partition plate 58 that axially divides the hollow portion 57a ​​of the shaft main body 57 is formed with through holes 58a that axially penetrate the partition plate 58. Furthermore, eight oil drain holes 59' that extend radially outwardly at equal intervals of 45 degrees in the circumferential direction and penetrate the shaft main body 57 are formed in a portion of the shaft main body 57 that corresponds to the second end plate 60 in the axial direction.

[0076] <Oil flow> In the rotor 40 configured as described above, fresh oil is supplied to the oil inlet hole 54 of the oil inlet portion 51 through the rotor-side oil passage 90, as shown by the thick arrow OF1D in Fig. 7. The fresh oil supplied to the oil inlet hole 54 is sent out radially to the outside of the rotor shaft 50 through the oil discharge hole 59 of the anti-output-shaft-side AOS, as shown by the thick arrow OF1E in Fig. 7, and also flows through the through-hole 58a and in the hollow portion 57a ​​of the shaft main body 57 to the output-shaft-side OS, as shown 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 shown 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 shown by thick arrows OF1F and OF1F' in Fig. 7, and is blown radially outward from the outer circumferential surfaces of first and second end plates 60 by centrifugal force, and is supplied to the 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 supplied simultaneously 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 first coil ends 17a but also stator core 11 and 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 showing a motor cooling system S2 according to this embodiment. Fig. 9 is a diagram showing a stator 10. Fig. 9(a) is a cross-sectional view showing 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), a third radial oil passage 127 extending in the same direction as the slots 25 is formed inside the first oil plate 120 by recessing a portion that defines the radially inner side of the annular space 26 radially inward. The third radial oil passages 127 are formed so that the number of the third radial oil passages 127 corresponds to the number of the 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 (the radially inner end) of the third radial oil passage 127. Note that, as in the first embodiment, the first and second radial oil passages 27, 28 have through holes 27a, 28a formed at the tip ends thereof on the surface of the counter-output shaft side AOS of the first oil plate 120.

[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 as to be concentric with the stator core 11 and so that 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 manner, 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 on the radial outside of each slot 15, penetrating the stator core 11 over the entire axial length. Instead of separately forming such axial oil passages 19, as shown in Fig. 9(c), 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'.

[0085] <Oil flow> In the stator 10 configured as 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] The fresh oil supplied to the annular space 26 flows down in 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 shown by the thin arrows in Fig. 9(a). 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 the first embodiment, 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 anti-output shaft side AOS, 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') penetrating 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 drain hole (not shown), for example, formed in the second oil plate 20'.

[0091] -Rotor- FIG. 10 is a diagram showing a rotor 40. More specifically, FIG. 10(a) is a perspective view showing an oil passage formed in the rotor 40, FIG. 10(b) is a perspective view showing a space formed in the first end plate 160, and FIG. 10(c) is a diagram explaining the space formed in the first end plate 160. Note that in FIG. 10(c), the permanent magnets 104 and 105 are omitted for ease of viewing. In addition, in the rotor 40 of this embodiment, the rotor shaft 50, the rotor core 41, and the second end plate 70 have the same configuration as those of 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, similarly to the first end plate 60. As shown in Figs. 10(a) and 10(b), a chamber space 162 having an annular shape in the axial direction is formed in the first end plate 160 concentrically with the axis AC. In addition, eight connecting passages 161 are also formed in the first end plate 160, which extend radially outward from the inner peripheral surface of the first end plate 160 at equal intervals of 45 degrees in the circumferential direction and are connected (communicated) 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 in the first end plate 160 on the AOS on the side opposite the output shaft from the chamber space 162. Like the first diffusion oil passage 63, each first diffusion oil passage 163 opens at the outer circumferential surface of the first end plate 160 and is formed so that the cross-sectional area increases as it goes radially outward. However, unlike the first diffusion oil passage 63, the radially inner end communicates with the chamber space 162 via a communication hole 164 as shown in FIG. 10(b).

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

[0095] A plurality of grooves are formed on the surface of the output shaft side OS of the first end plate 160, and when the surface of the output shaft side OS of the first end plate 160 is attached to the end surface of the AOS on the opposite side of the output shaft 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 AOS on the opposite side of the output shaft of the rotor core 41, and eight first radial oil passages 166 extending radially are formed on the output shaft side OS from the chamber space 162 as shown in Fig. 10(c). 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 the rotor core 41, and sixteen second radial oil passages 168 are also formed, which extend at an incline in the circumferential direction as they move radially outward on the output shaft side OS closer to the chamber space 162. The radially inner end of each second radial oil passage 168 communicates with the chamber space 162 via a communication hole 167. The length and inclination direction of each second radial oil passage 168 are set so that the radially outer end communicates with the gaps 43, 44 of the magnet hole.

[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 coincide circumferentially, as shown in Figure 10(c).

[0098] <Oil flow> Fig. 11 is a diagram showing a schematic of the oil passages and the flow of oil in rotor 40. More specifically, Fig. 11(a) is a cross-sectional view showing the oil passages in rotor core 41, and Fig. 11(b) is a perspective view showing the flow of oil in the entire rotor 40. Note that in Fig. 11(a), in order to make the drawing easier to see, hatching representing cross sections has been omitted, and oil is shown by the blackened portions.

[0099] In the rotor 40 configured as described above, fresh oil is supplied to the oil inlet hole 54 of the oil inlet portion 51 through the rotor-side oil passage 90, as shown by the thick arrows OF2E in Fig. 8 and Fig. 11(b). The fresh oil introduced into the oil inlet hole 54 flows sequentially through the oil inlet passage 50a, and is sent out radially to the outside of the rotor shaft 50 through the oil discharge holes 59, as shown by the thick arrows OF2F in Fig. 8 and Fig. 11(b). The fresh oil sent out to the outside of the rotor shaft 50 in this manner reaches the chamber space 162 through the connecting passage 161, and fills the chamber space 162, as shown by the thick arrows OF2G in Fig. 11(b).

[0100] 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 arrow 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, is blown 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] On the other hand, 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 arrow 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 arrow 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 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 inner side.

[0103] In addition, the oil that flows through the gaps 42, 43, 44 and reaches the end of the output shaft side OS of the rotor core 41 can be discharged to the outside of the rotor core 41 through a drain hole (not shown), for example, formed in the 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 stator core 11 and 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, and then is distributed within stator core 11 and 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, thereby making it possible to prevent the first diffusion oil passage 163 from being blocked by oil, and thereby making it possible to prevent negative pressure from being generated in the first diffusion oil passage 163 and thereby impairing the uniformity of the oil in the chamber space 162.

[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 to the oil flowing through the gaps 42, 43, 44 can be reduced, thereby making it possible to cool the permanent magnets 101, 102, ... more efficiently.

[0109] (Embodiment 3) This embodiment differs from the above-described embodiments 1 and 2 in that the second coil ends 17b are cooled. The following description will focus on the differences from embodiments 1 and 2.

[0110] -Cooling System- 12 is a vertical cross-sectional view showing a motor cooling system S3 according to the present embodiment. In the 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 showing a schematic of the oil plate 220 and the second end plate 170. More specifically, Fig. 13(a) is a cross-sectional view of the surface of the oil plate 220 facing the stator core 11, and Fig. 13(b) is a perspective view showing the second end plate 170. In this embodiment, the same oil guides 30 are attached to both ends of the anti-output-shaft-side AOS and the output-shaft-side OS of the stator core 11 so as to be symmetrical across the stator core 11 (see Fig. 14).

[0113] 12, in this embodiment, substantially the same oil plates 220 are attached to both ends of the anti-output-shaft AOS and the output-shaft OS of the stator core 11. The only difference between the first oil plate 220 of the anti-output-shaft AOS and the second oil plate 220 of the output-shaft OS is that the positions of through holes 127a and 227a are staggered in the circumferential direction, so the first oil plate 220 of the anti-output-shaft AOS will be described below as a representative example.

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

[0115] Thus, a through hole 227a penetrating the first oil plate 220 is formed on the radial outer side of a pair of slots 25 on which the third radial oil passage 127 is not formed on the radial outer side. Since the through hole 227a does 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 hole 227a. Note that, like the first and second embodiments, the through holes 27a, 28a are formed at the tip portions of the first and second radial oil passages 27, 28 on the surface of the oil plate 120 on the anti-output shaft side AOS.

[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 as to be concentric with the stator core 11 and so that 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 manner, 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 illustrates the flow of oil in the stator 10. Fig. 14(a) illustrates the flow of oil from the first oil plate 220 to the AOS on the counter-output shaft side, Fig. 14(b) illustrates the flow of oil from the first oil plate 220 to the OS on the output shaft side, Fig. 14(c) illustrates the flow of oil from the second oil plate 220 to the OS on the output shaft side, and Fig. 14(d) illustrates 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 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 arrow OF3A in Fig. 12 and Figs. 14(a) and (b). At this time, also on the output shaft side OS, fresh oil that has passed through the stator side oil passage 81 is supplied to the oil guide portion 31 of the second oil guide 30, as shown by the thick arrow OF3A' in Fig. 12 and Figs. 14(c) and (d).

[0119] Fresh oil supplied to the oil guide portion 31 is guided to the oil inlet port 29 of the first and second oil plates 220, and is supplied from the oil inlet port 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 in the annular space 26 while being branched (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 arrows OF3B' in Fig. 12 and Figs. 14(c) and (d).

[0120] In the first oil plate 220, a portion of the fresh oil filled in the annular space 26 is ejected from the through holes 27a formed at the tip of the first radial oil passage 27 and the through holes 28a formed at the tip of the second radial oil passage 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, a portion 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 filled in 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 filled in 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, 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, as shown by the thick arrow OF3D' in Figures 12 and 14(d). At this time, in the second oil plate 220, 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, as shown by the thick arrow OF3D in Figures 12 and 14(b).

[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 remaining portion of the fresh oil is supplied axially into the stator core 11, thereby efficiently cooling the first and second coil ends 17a, 17b and efficiently cooling the inside of the stator core 11 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 configurations as those in the second embodiment.

[0126] <End plate> Fig. 15 is a diagram showing a schematic diagram of oil passages and oil flow in rotor 40. More specifically, Fig. 15(a) is a perspective view showing oil passages formed in rotor 40, and Fig. 15(b) is a perspective view showing oil flow in rotor 40.

[0127] As shown in Fig. 13(b), the second end plate 170 has eight outer holes 171 with a circular cross section formed by recessing the surface of the AOS on the counter-output shaft side of the second end plate 170 toward the OS on the output shaft side at equal intervals of 45 degrees in the circumferential direction. 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 with a larger diameter than the outer holes 171 formed by recessing the surface of the AOS on the counter-output shaft side of the second end plate 170 toward the OS on the output shaft side radially inward of the outer holes 171. 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 in the radial direction 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 on the outer peripheral surface of the second end plate 170, and is formed so that the cross-sectional area increases toward the radially outer side. Similarly, the second end plate 170 is formed with sixteen second long diffusion oil passages 174 extending in the radial direction. Like the second short diffusion oil passages 172, each second long diffusion oil passage 174 communicates with the inner hole 173, opens on the outer peripheral surface of the second end plate 170, and is formed so that the cross-sectional area increases toward the radially outer side.

[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 surface 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 in the circumferential direction, the second short diffusion oil passage 172 and the gap 42 are communicated via the outer hole 171, and the second long diffusion oil passage 174 and the gaps 43, 44 are communicated 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, by using a sand mold for casting, or by forming the second end plate 170 as two plates (not shown) that are divided into two in the axial direction, and providing grooves or holes that become part of the oil passage 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 is omitted.

[0132] The oil that flows through gaps 42, 43, 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 thick arrow OF3K in Figures 12 and 15(b), and is thrown radially outward from the outer circumferential surface of second end plate 170 by centrifugal force through second short diffusion oil passage 172 and second long diffusion oil passage 174, and is supplied from the radially inner side to the 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, since 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 been heated to a certain degree) after cooling rotor core 41 and the like, but since the number (24) of second short diffusion oil passages 172 and second long diffusion oil passages 174 is set to be greater than the number (8) of first diffusion oil passages 163, in other words, the amount of oil supplied to second coil ends 17b is relatively greater, so that second coil ends 17b can also be efficiently cooled.

[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, so that each part of the motor 1, including the first coil end 17a, can be cooled efficiently over a wider area.

[0136] (Other embodiments) The present invention is not limited to the embodiments, and can be embodied 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, but this is not limited thereto. 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 FIG.

[0138] In addition, in each of the above embodiments, the through holes 27a, 28a extending straight in the axial direction are exemplified, but this is not limited thereto. For example, the through holes may be formed so as to extend at an inclination radially inward as they move 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 limited to this, 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 above-mentioned second and third embodiments, the permanent magnets 101, 102, 103, and 106 are targeted for cooling, but this is not limiting, and the permanent magnets 104 and 105 may also be cooled by increasing the number of radial oil paths.

[0141] As such, the above-described embodiment is merely illustrative in all respects and should not be construed as limiting. Furthermore, all modifications and variations 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 efficiently cooled, and therefore the present invention is extremely useful when applied to a motor cooling system that supplies cooling oil to each part of a 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 (ring-shaped space) 40 Rotor 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 (ring-shaped 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 a portion of the 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 supplied to a coil end on one axial side of the stator coil without flowing within the stator core, and at least a portion of the remaining oil passes through the annular space and is supplied axially into the stator core, The motor cooling system is characterized in that the rotor is configured such that a portion of the oil that has passed through the rotor-side oil passage passes through a ring-shaped space formed concentrically with the rotor core within an end plate attached to one end of the rotor core in the axial direction, and is supplied from the radially inner side to the coil end on one axial side without flowing within the rotor core, and the remainder of the oil is supplied axially into the rotor core through the ring-shaped space.

2. 2. The motor cooling system according to claim 1, 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 motor cooling system is characterized in that the rotor is configured such that oil supplied into the rotor core reaches the other axial end of the rotor core and then is supplied from the radially inner side to the coil end on the other axial side.

3. 2. The motor cooling system according to claim 1, The rotor core has a plurality of magnet holes extending in the axial direction and into which permanent magnets are embedded, The stator is configured such that oil supplied into the stator core flows in an axial direction through slots formed in the stator core and between the stator coil 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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