Rotating electric machine

Abstract

This enables efficient supply of refrigerant to desired locations in a rotating electric machine without the need for pressurized refrigerant transport. [Solution] A rotating electric machine is disclosed, comprising a rotor arranged on a vehicle with its axis of rotation in a vertical direction, a stator provided with respect to the rotor, and a refrigerant flow path in the vertical direction. For example, the rotor or the stator has slots around which coils are wound, and the refrigerant flow path includes a space formed by the slots. Preferably, the machine further comprises wall-forming members that form wall portions extending axially and circumferentially on the radially inward and radially outward sides of the slots. Preferably, the rotor has a hollow shaft, and the refrigerant flow path includes a space formed inside the hollow shaft.

Description

Technical Field

[0001] The present disclosure relates to a rotating electric machine.

Background Art

[0002] A technique for supplying oil pumped from an oil pump to a rotating electric machine is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology as described above, an oil pump for supplying oil to the rotating electric machine is required, and there is a problem that the flow path configuration and seal structure of the pumped oil become complicated.

[0005] Therefore, on one aspect, an object of the present disclosure is to enable efficient supply of oil to a desired location of a rotating electric machine without performing oil pumping.

Means for Solving the Problems

[0006] On one aspect, a rotating electric machine is provided, which includes a rotor disposed in a vehicle with the rotation axis in the vertical direction, a stator provided for the rotor, and a refrigerant flow path in the vertical direction.

Effects of the Invention

[0007] On one aspect, according to the present disclosure, it is possible to efficiently supply refrigerant to a desired location of a rotating electric machine without performing refrigerant pumping.

Brief Description of the Drawings

[0008] [Figure 1] This is a schematic cross-sectional view showing the cross-sectional structure of a rotating electric machine to which this embodiment is applied. [Figure 1A] This diagram schematically shows the vehicle mounting configuration of a rotating electric machine. [Figure 2] This is an explanatory diagram of how to extract the output from a rotating electric machine. [Figure 3] This is a schematic diagram illustrating the flow of refrigerant within the slot in this embodiment. [Figure 4] This is a schematic diagram illustrating the flow of refrigerant within the slot in the comparative example. [Figure 5] This is a cross-sectional view showing a modified example. [Figure 6] This is a cross-sectional view showing further variations. [Figure 7] This is a perspective view showing the entire rotating electric machine 1. [Figure 8] This is a perspective view of the guide cuff in its individual state. [Figure 9] This is a magnified view of a portion of Figure 8. [Figure 10] This is a cross-sectional view showing the state within one slot. [Figure 11] This is a perspective view of the catch cover in its individual form. [Figure 12] This is a cross-sectional view showing the flow of the refrigerant. [Figure 13] This is a cross-sectional view showing further variations. [Modes for carrying out the invention]

[0009] The following describes each embodiment in detail with reference to the attached drawings. Note that the dimensional ratios in the drawings are merely examples and are not exhaustive. Furthermore, shapes and other details in the drawings may be partially exaggerated for illustrative purposes. Also, for clarity, in some cases, only a portion of parts with the same attribute are assigned reference numerals in the drawings.

[0010] Figure 1 is a schematic cross-sectional view showing the cross-sectional structure of the rotating electric machine 1 to which this embodiment is applied.

[0011] In FIG. 1, the rotating shaft 12 of the rotating electrical machine 1 is illustrated. In the following description, the axial direction refers to the direction in which the rotating shaft (rotation center) 12 of the rotating electrical machine 1 extends. The outer side in the axial direction refers to the side away from the axial center C0 of the stator core 211, and the inner side in the axial direction refers to the side toward the axial center C0 of the stator core 211. Also, the radial direction refers to the radial direction centered on the rotating shaft 12. The outer side in the radial direction refers to the side away from the rotating shaft 12, and the inner side in the radial direction refers to the side toward the rotating shaft 12. In FIG. 1, together with the Z direction parallel to the axial direction, the Z1 side and the Z2 side are defined. In FIG. 1, together with the R direction parallel to the radial direction, the R1 side (inner side in the radial direction) and the R2 side (outer side in the radial direction) are defined. In FIGS. 2 and later, the Z direction and the R direction are appropriately shown.

[0012] The rotating electrical machine 1 may be, for example, a motor for vehicle drive used in a hybrid vehicle or an electric vehicle. However, the rotating electrical machine 1 may be used for any other arbitrary application.

[0013] The rotating electrical machine 1 is of an inner rotor type, and the stator 21 is provided so as to surround the outer side in the radial direction of the rotor 30. The outer side in the radial direction of the stator 21 is fixed to the motor housing 10. The fixing method is arbitrary and may be, for example, shrink fitting or bolt fastening. The stator 21 includes, for example, a stator core 211 made of a laminated steel sheet of an annular magnetic material. A plurality of slots 213 around which the stator coils 22 are wound are formed on the inner side in the radial direction of the stator core 211.

[0014] In this embodiment, the stator coil 22 is made of a rectangular wire. The stator coil 22 may be formed by a segment coil including a U-shaped form when viewed perpendicular to the axial direction.

[0015] The stator coil 22 includes a slot insertion portion 222 and a coil end portion 223. The slot insertion portion 222 is inserted into the slot 213 of the stator core 211. The slot insertion portion 222 is disposed in each slot 213. Note that insulating paper 225 (see FIG. 10) may be disposed around the slot insertion portion 222. The coil end portion 223 extends axially outward from the axial end surface 2110 of the stator core 211 and connects between the plurality of slot insertion portions 222 located in different slots 213. Note that an insulating material such as varnish may be applied to the coil end portion 223.

[0016] The rotor 30 is disposed radially inside the stator 21.

[0017] The rotor 30 includes a rotor core 32, a rotor shaft 34, end plates 35A and 35B, and magnets 42.

[0018] The rotor core 32 is fixed to the radially outer surface of the rotor shaft 34 and rotates integrally with the rotor shaft 34. The rotor core 32 has a shaft hole 320, and the rotor shaft 34 is fitted into the shaft hole 320. The rotor core 32 may be fixed to the rotor shaft 34 by shrink fitting, press fitting, or the like. For example, the rotor core 32 may be coupled to the rotor shaft 34 by a key connection or a spline connection. The rotor shaft 34 is rotatably supported by the motor housing 10 via a bearing 14a (shown only on the Z1 side). Note that the rotor shaft 34 defines the rotating shaft 12 of the rotating electrical machine 1.

[0019] The rotor core 32 is formed of, for example, a laminated steel sheet of an annular magnetic material. Magnets 42 are embedded inside the rotor core 32. That is, the rotor core 32 has magnet holes 322 penetrating in the axial direction, and the magnets 42 are inserted and fixed in the magnet holes 322. Note that in a modified example, the rotor core 32 may be formed of a compacted body in which magnetic powder is compressed and solidified.

[0020] Although Figure 1 shows a rotating electric machine 1 with a specific structure, the structure of the rotating electric machine 1 is not limited to this specific structure. For example, in Figure 1, the rotor shaft 34 is hollow, but it may be solid. Also, the magnets 42 and / or end plates 35A, 35B may be omitted. The rotor may have field windings. Furthermore, it may not be an inner rotor type; for example, it may be an outer rotor type.

[0021] Figure 1A schematically shows the vehicle mounting state of the rotating electric machine 1, illustrating the vehicle in a side view while schematically showing the rotating electric machine 1 in a perspective view. Note that the mounting position of the rotating electric machine 1 in the longitudinal direction and in the height direction of the vehicle are arbitrary and not limited to the position shown in Figure 1A. In this embodiment, a characteristic configuration is that the rotating electric machine 1 is positioned vertically. That is, the rotating electric machine 1 is positioned so that its axial direction is vertical (direction of gravity). In this case, the rotation axis 12 of the rotor 30 is parallel to the vertical direction, but it may be tilted with respect to the vertical direction within a range of -45 degrees to 45 degrees.

[0022] Figure 2 is an explanatory diagram of the method for extracting the output of the rotating electric machine 1.

[0023] In this embodiment, the output of the rotating electric machine 1 is rotational torque around the rotating shaft 12, which is converted into rotational torque around the rotating shaft 14 in the horizontal plane. In this case, such conversion may be achieved via the cross-axis gear 70, as shown in Figure 2. The output after conversion may be transmitted to the wheels via a reduction mechanism or a differential gear mechanism.

[0024] Next, the refrigerant flow path configuration and its effects in this embodiment will be explained with reference to Figures 1, 3, and 4.

[0025] Figure 3 is a schematic diagram illustrating the flow of refrigerant in slot 213 in this embodiment, and Figure 4 is a schematic diagram illustrating the flow of refrigerant in slot 213 in a comparative example. Figures 3 and 4 show only a schematic cross-section on one radial side with respect to the rotation axis 12 (the same applies to Figure 5, which will be shown later).

[0026] According to this embodiment, as described above, the rotating electric machine 1 is positioned vertically, so that the refrigerant (e.g., oil or cooling water) can be flowed from top to bottom using gravity. This makes it possible to efficiently supply the refrigerant to the desired location on the rotating electric machine 1 without pressurizing the refrigerant.

[0027] For example, in Figure 1, the flow of refrigerant is schematically shown by arrows R10 to R15. In this case, the refrigerant flow path 90 includes an axial inlet flow path 91, a radial flow path 92, a circumferential flow path 93, a shaft in-flow flow path 94, and a slot in-flow flow path 98.

[0028] The axial inlet passage 91, the radial passage 92, and the circumferential passage 93 are provided in the upper part of the rotating electric machine 1 in the motor housing 10. The axial inlet passage 91 is provided concentrically with the rotating shaft 12 and communicates with the upper end of the shaft internal passage 94. The radial passage 92 has a concentric conical upper surface shape with the rotating shaft 12, and its radially outer side communicates with the circumferential passage 93. The circumferential passage 93 may have an annular shape that overlaps the coil end portion 223 when viewed in the axial direction, and its axial lower side is open.

[0029] With this refrigerant flow path configuration, the refrigerant supplied from the top of the motor housing 10 (see arrow R10) is distributed to the axial inlet flow path 91 and the radial flow path 92 (see arrows R11 and R12). The method of supplying the refrigerant from the top of the motor housing 10 is arbitrary; other gear-driven pumping may be used, or an oil pump may be used.

[0030] The refrigerant flowing through the shaft inlet passage 91 cools the rotor shaft 34 as it passes through the hollow interior of the rotor shaft 34. The refrigerant inside the rotor shaft 34 is also discharged radially outward through the radial holes by centrifugal force (arrow R13), cooling the coil end portion 223 from the radial inside. The refrigerant flowing radially outward through the radial passage 92 reaches the circumferential passage 93, from which it drips onto the upper part of the coil end portion 223. The oil dripped onto the upper part of the coil end portion 223 cools the coil end portion 223 and also cools the entire stator coil 22 by passing through the slot passage 98 in the slot 213 of the stator coil 22 (see also arrow R15 in Figure 3) (see Figure 3).

[0031] In this embodiment, gravity enables efficient supply of refrigerant to desired locations on the rotating electric machine 1.

[0032] In the comparative example shown in Figure 4, the rotating electric machine 1' is positioned horizontally. In this case, in order to flow the refrigerant into the slot 213, it is necessary to pressurize the refrigerant (see arrow R41). In this case, the refrigerant pressure becomes high, making it easier for the refrigerant to leak from the axial gap of the stator core 211 (the gap between the steel plates) into the radial gap (air gap) between the rotor core 32 and the stator core 211 (see arrow R42). Such refrigerant leakage creates resistance to the rotation of the rotor 30, resulting in losses (so-called drag losses).

[0033] In contrast, this embodiment can resolve the problems that arise in the comparative example. Specifically, since there is no need to pump the refrigerant under pressure, refrigerant leakage is less likely to occur, and the sealing structure and other components can be simplified.

[0034] In this embodiment, the refrigerant flow path 90 shown in Figures 1 and 3 is merely an example, and various modifications are possible, such as adding other flow paths or changing some of the flow paths, as shown in Figures 5 and 6.

[0035] For example, as shown in Figure 5, the stator core 211 may be provided with a refrigerant passage 95 that penetrates vertically in locations other than the slots 213. Alternatively, as shown in Figure 6, an annular C-shaped cross section member 96 for accumulating refrigerant may be provided at the upper end of the rotor shaft 34 at the inlet to the shaft passage 94, and an axial hole 97 may be provided on the radially outer side of the bottom of the C-shaped cross section member 96. In this case, oil can be supplied to the shaft passage 94 through the hole 97. Note that in Figures 5 and 6, the refrigerant is schematically shown in the hatched area C. Note that Figure 6 shows only the cross section of the rotor 30 with the end plates 35A and 35B omitted, and arrow R60 schematically represents the rotation state of the rotor 30 (the state in which centrifugal force is generated).

[0036] Next, referring to Figure 7 and subsequent figures, a preferred configuration for flowing refrigerant through the slot 213 (slot passage 98) will be described. Regarding the following rotating electric machine 1A, components that may be the same as those in the rotating electric machine 1 described above are given the same reference numerals and their descriptions may be omitted.

[0037] Figure 7 is a perspective view showing the entire rotating electric machine 1A, Figure 8 is a perspective view of the guide cuff 60 in its individual state, and Figure 9 is an enlarged view of a part of Figure 8. Figure 10 is a cross-sectional view showing the state inside one slot 213, and is a cross-sectional view taken from a plane perpendicular to the rotating shaft 12. Figure 11 is a perspective view of the catch cover 50 in its individual state, viewed from above. Figure 12 is a cross-sectional view showing the flow of the refrigerant, and is a schematic cross-sectional view passing through the rotating shaft 12. In Figure 12, only the cross-section on one radial side with respect to the rotating shaft 12 is schematically shown (the same applies to Figure 13, which will be shown later).

[0038] In the rotating electric machine 1A shown in Figures 7 to 12, a guide cuff 60 is provided on the upper axial end face 2110 of the stator core 211. The guide cuff 60 has an annular and flat main body portion 61. The main body portion 61 of the guide cuff 60 covers the area of ​​the entire upper axial end face 2110 of the stator core 211, excluding the slots 213. Specifically, as shown in Figures 8 and 9, the main body portion 61 of the guide cuff 60 has an axial opening 61a at a circumferential position corresponding to the slots 213. The opening 61a may have the same shape as the slots 213, but preferably, as shown in Figure 9, it has a circumferential projection 612 that forms a radial gap between the slot insertion portions 222. The circumferential projections 612 may be provided in pairs facing each other on both sides of a single opening 61a in the circumferential direction. In this case, the pair of circumferential protrusions 612 are spaced apart from each other in the circumferential direction, forming an entrance to the slot channel 98. In the illustrated example, the slot channel 98 is formed between the slot insertion portions 222 of the first and second turns and the slot insertion portions 222 of the second and third turns, as shown in Figure 10, and penetrates axially. Note that the multiple slot insertion portions 222 within a single slot 213 may be entirely surrounded by insulating paper 225, as shown in Figure 10.

[0039] The guide cuff 60 forms an inner diameter side wall portion 62 that extends axially and circumferentially, radially inward from the slot 213. The inner diameter side wall portion 62 may be formed continuously over the entire circumferential direction. The inner diameter side wall portion 62 may be provided at a radial position adjacent to the radially inner edge of the slot 213.

[0040] The guide cuff 60 forms an outer diameter side wall portion 63 that extends axially and circumferentially, radially outward from the slot 213. The outer diameter side wall portion 63 may be formed continuously over the entire circumferential direction. The outer diameter side wall portion 63 may be provided at a radial position radially outward from the radial outer edge of the slot 213 (for example, at the radial position where the radial outer edge of the stator core 211 is located).

[0041] By providing such a guide cuff 60, the refrigerant supplied from the upper side of the rotating electric machine 1 can be reliably guided into the slot passage 98. In other words, the inner diameter side wall portion 62 and the outer diameter side wall portion 63 of the guide cuff 60 act as a dam, allowing the refrigerant to accumulate. By appropriately setting the heights of the inner diameter side wall portion 62 and the outer diameter side wall portion 63, the refrigerant accumulated in the guide cuff 60 can be reliably guided into the slot passage 98.

[0042] In the rotating electric machine 1A, a catch cover 50 is provided on the lower side of the stator core 211. The catch cover 50 is provided in a manner that faces the lower coil end portion 223 in the axial direction. As can be seen from Figures 11 and 12, the catch cover 50 has an annular shape with a C-shaped cross section that opens at the top. The catch cover 50 flows downward through the slot passage 98 and captures the refrigerant dripping from the lower coil end portion 223.

[0043] The refrigerant captured by the catch cover 50 is the same refrigerant used to cool the rotating electric machine 1, and therefore can reach a relatively high temperature. Consequently, the refrigerant captured by the catch cover 50 may be supplied as a heating medium to the object to be heated (for example, the power supply for the rotating electric machine 1). In configurations where such supply to the object to be heated is unnecessary, the catch cover 50 may be omitted.

[0044] Note that the configurations shown in Figures 7 to 12 are merely examples, and various modifications are possible, such as adding other flow paths or changing some of the flow paths, as shown in Figure 13. In the example shown in Figure 13, a recess 324 is formed on the upper axial end face 2110 of the rotor core 32 instead of the guide cuff 60. The recess 324 extends in the circumferential direction and forms an inner diameter side wall portion 62A corresponding to the inner diameter side wall portion 62 of the configuration shown in Figures 7 to 12, and an inner diameter side wall portion 63A corresponding to the outer diameter side wall portion 63 of the configuration shown in Figures 7 to 12.

[0045] Although each embodiment has been described in detail above, the invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope described in the claims. Furthermore, it is possible to combine all or more of the components of the embodiments described above.

[0046] For example, in the embodiment described above, the rotor 30 does not have coils wound around it, but this can also be applied to a field-wound type in which the rotor 30 has coils wound around it. In this case, a similar refrigerant flow path may be formed in the slot (not shown) into which the coils of the rotor 30 are inserted. [Explanation of Symbols]

[0047] 1 Rotating electric machine, 21 Stator, 213 Slot, 30 Rotor, 34 Rotor shaft (hollow shaft), 90, 95 Coolant flow path, 60 Guide cuff (wall forming member), 62 Inner diameter side wall (wall), 63 Outer diameter side wall (wall)

Claims

1. A rotor positioned on the vehicle with its axis of rotation facing vertically, A stator provided with respect to the rotor, A rotating electric machine equipped with a refrigerant flow path in the vertical direction.

2. The rotor or stator has slots around which coils are wound, The rotating electric machine according to claim 1, wherein the refrigerant flow path includes a space formed by the slot.

3. The rotating electric machine according to claim 2, further comprising a wall-forming member that forms wall portions extending axially and circumferentially on the radially inward and radially outward sides of the aforementioned slot.

4. The rotor has a hollow shaft, The rotating electric machine according to claim 1, wherein the refrigerant flow path includes a space formed inside the hollow shaft.

Images