Rotating electric machine

Abstract

To provide a rotary electric machine capable of increasing motor efficiency by appropriately cooling a permanent magnet.SOLUTION: A cylindrical part 21 has a radial through-hole 241 penetrating from the inner peripheral surface of a recess 24 to a permanent magnet 22 in a radial direction, an axial through-hole 242 penetrating from one end 20a side of the permanent magnet 22 to the other end 20b side in an axial direction, and an opening 243 open at the other end 20b of the axial through-hole 242. A housing 10 is provided with a pedestal 12 that rotatably supports a rotary shaft. The pedestal 12 is provided with a refrigerant inlet 14 for introducing a refrigerant into the housing 10. The refrigerant introduced from the refrigerant inlet 14 is distributed from the recess 24 through the radial through-hole 241 and the axial through-hole 242 to the opening 243.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Since a rotating electric machine generates heat during its operation, it is necessary to appropriately cool the stator and the rotor respectively. Usually, the stator can be cooled by providing a refrigerant flow path in a yoke or a housing that covers its periphery. On the other hand, since the rotor is always rotating, it is difficult to provide a refrigerant flow path, and thus a special cooling technique is required.

[0003] Patent Document 1 discloses a configuration in which an oil reservoir is arranged inside the diameter of a rotor in which permanent magnets are embedded, and the oil (refrigerant) stored in the oil reservoir is scattered toward the inner circumference of a cylindrical portion by centrifugal force accompanying the rotation of the rotor, thereby cooling the cylindrical portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] In a configuration in which the refrigerant is scattered toward the inner circumference of the rotor by centrifugal force as in the prior art, the permanent magnets embedded in the rotor cannot be directly cooled. Therefore, since the permanent magnets are not sufficiently cooled, there is a problem that there is a limit to improving the motor efficiency.

[0006] An object of the present invention is to provide a rotating electric machine that can appropriately cool the permanent magnets installed inside the rotor and improve the motor efficiency.

[0007] One aspect of the present invention is applied to a rotating electric machine comprising a rotor, a stator provided on the outer circumference of the rotor, and a housing that accommodates the rotor and the stator. The rotor comprises a rotating shaft, a cylindrical portion equipped with permanent magnets, and a connecting portion connecting the outer surface of the rotating shaft and the inner surface of the cylindrical portion. The rotor has an annular recess, which is a space formed by the rotating shaft, the cylindrical portion, and the connecting portion, and which opens axially across the connecting portion. The housing comprises a base that rotatably supports the rotating shaft. The base is provided with a refrigerant introduction hole for introducing a refrigerant toward the annular recess. The rotor has a radial through hole that penetrates the cylindrical portion radially in the annular recess, and an axial through hole that communicates with the radial through hole and penetrates the inside of the rotor axially, and the refrigerant introduced into the annular recess cools the permanent magnets by passing through the radial through hole and the axial through hole. The inner circumferential surface of the cylindrical portion has an enlarged diameter portion on the connection side, where the inner diameter is wider than the inner diameter on the opening side of the annular recess, via a stepped portion, and the radial through hole is formed in the stepped portion of the enlarged diameter portion.

[0008] According to the present invention, the refrigerant introduced from the refrigerant inlet hole of the base into the annular recess of the rotor flows through radial and axial through holes inside the rotor, thereby directly supplying the refrigerant to the permanent magnets provided on the rotor. As a result, the permanent magnets are properly cooled, and the motor efficiency can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an axial cross-sectional view of the motor according to this embodiment. [Figure 2] Figure 2 is a perspective view of the rotating shaft and cylindrical portion that constitute the rotor. [Figure 3] Figure 3 is a perspective view of the rotor with permanent magnets attached. [Figure 4] Figure 4 is a perspective view of the rotor with the end plates attached. [Figure 5] Figure 5 is a radial cross-sectional view of the rotor. [Figure 6] Figure 6 is an axial cross-sectional view of the rotor centered on the annular recess. [Figure 7] Figure 7 is an explanatory diagram showing the refrigerant flow path. [Figure 8]Figure 8 is an explanatory diagram showing another example of a refrigerant flow path. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the attached drawings.

[0011] Figure 1 is an explanatory diagram of a motor 1 as a rotating electric machine according to an embodiment of the present invention, and shows a cross-sectional view in the axial direction.

[0012] The motor 1 comprises a stator 15 formed in an annular shape, a rotor 20 rotatably mounted inside the stator 15, and a housing 10 that houses the stator 15 and the rotor 20.

[0013] The motor 1 of this embodiment is mounted on an electric vehicle or a hybrid vehicle and functions as an electric motor that drives the wheels. Furthermore, the motor 1 also functions as a generator that generates electricity (regenerative braking) by receiving the driving force from the rotation of the wheels. The motor 1 may also be used in devices other than automobiles, such as drive systems for various electrical equipment or industrial machinery.

[0014] The stator 15 is constructed by laminating electrical steel sheets. Windings are inserted into slots (not shown) formed in the stator 15. Coil ends, formed by folding the windings, protrude from the axial ends of the stator 15. A first coil end 151 protrudes axially from one end of the stator 15 (left side in Figure 1). A second coil end 152 protrudes axially from the other end of the stator 15 (right side in Figure 1). By passing current through the windings of the stator 15, the rotor 20 rotates in interaction with the permanent magnets 25 provided on the rotor 20.

[0015] The rotor 20 is comprised of a rotating shaft 21, a cylindrical portion 22, and a permanent magnet 25.

[0016] The cylindrical portion 22 is a cylindrical member arranged to surround the outer circumference of the rotating shaft 21. The cylindrical portion 22 is arranged to be concentric with the rotating shaft 21. The rotating shaft 21 and the cylindrical portion 22 are connected by a connecting portion 23 that extends radially from the outer circumferential surface of the rotating shaft 21 and connects to the inner circumferential surface of the cylindrical portion 22. An annular permanent magnet 25 is fixed to the outer circumference of the cylindrical portion 22. The permanent magnet 25 is arranged such that a plurality of segment magnets 251 as described later in FIG. 4 are arranged in an annular manner so as to have a plurality of magnetic poles in the circumferential direction. The magnetic poles of the permanent magnet 35 are arranged in a Halbach array. The Halbach array is an arrangement in which the directions of adjacent magnetic poles in the circumferential direction are different by 90 degrees.

[0017] A cylindrical holding member 202 for fixing the permanent magnet 25 is provided on the outer circumference of the permanent magnet 25. Disk-shaped end plates 201 (201a, 201b) are provided at both axial ends of the permanent magnet 25, respectively.

[0018] In the rotor 20, an annular recess 24a is formed in a space formed by the rotating shaft 21, the cylindrical portion 22, and the connecting portion 23, and opens to one axial end 20a (the left side in FIG. 1) side across the connecting portion 23. Similarly, on the other end 20b (the right side in FIG. 1) side of the rotor 20, an annular recess 24b is formed which is formed by the rotating shaft 21, the cylindrical portion 22, and the connecting portion 23 and opens to the other axial end 20b side across the connecting portion 23.

[0019] The rotating shaft 21 of the rotor 20 is rotatably supported by bearings 13 (13a, 13b) whose both ends are fixed to the through portions of the inner circumferences of pedestals 12 (12a, 12b) formed in the housing 10.

[0020] The pedestal 12a is formed to project from the housing 10 on the one end 20a side of the rotor 20 toward the rotor 20 side. A part of the pedestal 12a is formed to enter inside the annular recess 24a more than the one end 20a of the rotor 20.

[0021] Similarly, the pedestal 12b is formed to project from the housing 10 on the other end 20b side of the rotor 20 toward the rotor 20, and a part of the pedestal 12b is formed to enter inside the annular recess 24b more than the other end 20b of the rotor 20.

[0022] The pedestal 12a has a refrigerant introduction hole 14 for introducing refrigerant into the housing. A plurality (for example, eight) of refrigerant introduction holes 14 are provided along the periphery of the bearing 13a. The refrigerant introduction hole 14 is configured to introduce refrigerant toward the inside of the housing 10, particularly inside the annular recess 24a of the rotor 20. As the refrigerant, for example, insulating oil is used, but water such as cooling water, or other fluids or gases may also be used.

[0023] In the annular recess 24a of the rotor 20, radial through-holes 241 having a circular cross-section penetrating from the inner wall to the outer periphery of the annular recess 24a are formed. On the outer peripheral side of the annular recess 24a, between the cylindrical portion 22 and the permanent magnet 25, axial through-holes 242 having a rectangular cross-section extending axially and communicating with the radial through-holes 241 are formed. A plurality of radial through-holes 241 and axial through-holes 242 are formed in the circumferential direction of the rotor 20. At a position corresponding to the axial through-hole 242 on the end plate 201b on the other end 20b side of the axial through-hole 242, an opening 243 having a circular cross-section is formed.

[0024] The refrigerant introduced from the refrigerant introduction hole 14 flows inward from one end 20a side of the annular recess 24a. The refrigerant moves to the inner peripheral surface side of the annular recess 24a by the centrifugal force caused by the rotation of the rotor 20. The refrigerant flows into the radial through-hole 241 by the centrifugal force and flows from the radial through-hole 241 into the axial through-hole 242. The refrigerant further moves from one end 20a side to the other end 20b side through the axial through-hole 242. The refrigerant reaching the other end 20b side of the axial through-hole 242 flows out of the rotor 20 from the opening 243. This refrigerant scatters toward the second coil end 152 of the stator 15 by the centrifugal force caused by the rotation of the rotor 20.

[0025] Of the refrigerant introduced into the annular recess 24a, any refrigerant that does not pass through the radial through-hole 241 flows outward through the opening of the annular recess 24a. Due to the centrifugal force caused by the rotation of the rotor 20, this refrigerant moves radially outward through the gap between the rotor 20 and the base 12a of the housing 10 and is scattered toward the first coil end 151 of the stator 15.

[0026] In this configuration, the refrigerant introduced from outside the motor 1 into the housing 10 cools the rotor 20 by passing through the axial through-holes 242 formed in the rotor 20. The refrigerant also cools the first coil end 151 and the second coil end 152 of the stator 15 by splashing onto them. The refrigerant then flows down into the refrigerant reservoir 18 (see Figure 7) formed at the bottom of the housing 10. This refrigerant is then introduced back into the housing 10 through the refrigerant introduction hole 14.

[0027] Next, we will explain the configuration of the rotor 20 in more detail.

[0028] Figure 2 is a perspective view of the rotating shaft 21 and cylindrical portion 22 that constitute the rotor 20 of this embodiment. Figure 3 is a perspective view of the rotor 20 with the permanent magnet 25 attached. Figure 4 is a perspective view of the rotor 20 with the end plate 201 attached. Figure 5 is a radial cross-sectional view of the rotor 20.

[0029] As shown in Figure 2, a plurality of grooves 225 are formed on the outer circumferential surface of the cylindrical portion 22, extending in the axial direction. At one end of each groove 225, on the side of 20a (the foreground side in Figure 2), a radial through-hole 241 is formed, which penetrates radially through the inner circumference of the cylindrical portion 22, i.e., the annular recess 24a and the groove 225.

[0030] The groove 225 is formed by a pair of upright walls 221 that rise from the outer circumference of the cylindrical portion 22. The upright walls 221 are wall-shaped portions that extend linearly in the axial direction, and a plurality of upright walls 221 are arranged at predetermined intervals in the circumferential direction of the cylindrical portion 22. On the outer circumference of the cylindrical portion 22, upright walls 221a with a higher upright height and upright walls 221b with a lower upright height than upright walls 221a are arranged alternately.

[0031] The groove 225 has a permanent magnet 25 positioned on its outer circumference, so that the inner surface of the permanent magnet 25 is in contact with the upper surface of the upright wall 221, forming an axial space enclosed by the permanent magnet 25 and a pair of upright walls 221 (see Figure 3). This space is configured as an axial through-hole 242 through which the coolant flows in the axial direction of the rotor 20. As shown in Figure 3, a cylindrical retaining member 202 is fitted around the outer circumference of the permanent magnet 25 to hold the permanent magnet 25.

[0032] As shown in Figure 4, annular end plates 201a and 201b are positioned at one end 20a and the other end 20b of the rotor 20, respectively, to fix the permanent magnet 25 in the axial direction, and the axial through hole 242 is closed by the one end 20a and the other end 20b.

[0033] As shown in Figure 5, the permanent magnet 25 of the rotor 20 is composed of multiple fan-shaped segment magnets 251 arranged in a ring. Each segment magnet 251 consists of a segment magnet 251a that contacts a pair of upright walls 221a and a segment magnet 251b that contacts a pair of upright walls 221b, with the segment magnets 251a and 251b being arranged alternately. These segment magnets 251 are arranged such that the orientation of the magnetic poles of adjacent segment magnets 251 differs by 90 degrees.

[0034] The segment magnet 251a has a flat inner surface, and when it comes into contact with the upper surface of a pair of upright walls 221a, an axial through hole 242 is formed.

[0035] The segment magnet 251b is formed such that its inner circumferential surface is closer to the cylindrical portion 22 than the segment magnet 251a, and has a recess 255b that is recessed radially outward. When the segment magnet 251b contacts the upper surface of a pair of upright walls 221b, an axial through hole 242 is formed by the recess 255b of the segment magnet 251b and the pair of upright walls 221b.

[0036] With this configuration, an axial through-hole 242 is formed between the cylindrical portion 22 and the permanent magnet 25, allowing the refrigerant flowing through the axial through-hole 242 to come into direct contact with the permanent magnet 25 and perform heat exchange with it. This improves the cooling efficiency of the permanent magnet 25 of the rotor 20 by the refrigerant. By improving the cooling efficiency of the permanent magnet 25, demagnetization due to heat of the permanent magnet 25 can be suppressed, and the efficiency of the motor 1 can be improved.

[0037] Furthermore, by alternately arranging segment magnets 251a and 251b, which have different shapes at the points that contact the cylindrical portion 22, the ring-shaped permanent magnet 25 is prevented from rotating relative to the cylindrical portion 22.

[0038] Next, the structure of the annular recess 24a will be described.

[0039] Figure 6 is an axial cross-sectional view of the rotor 20 centered on the annular recess 24a.

[0040] The annular recess 24a is a space formed by the outer circumferential surface of the rotating shaft 21, the inner circumferential surface of the cylindrical portion 22, and the connecting portion 23. The annular recess 24a has a small-diameter portion 245 with a small cross-sectional area on the opening side, and an enlarged-diameter portion 246 on the connecting portion 23 side of the small-diameter portion 245, which has a larger radial cross-sectional area, i.e., is radially expanded. Between the small-diameter portion 245 and the enlarged-diameter portion 246, there is a stepped portion 247 in which the cross-sectional area of ​​the annular recess 24a expands in a step-like or tapered manner. A radial through hole 241 is formed in the stepped portion 247.

[0041] Because the annular recess 24a has this shape, the refrigerant introduced into the annular recess 24a from the refrigerant introduction hole 14 of the base 12a moves radially outward from the annular recess 24a due to the centrifugal force caused by the rotation of the rotor 20, and is stored on the inner circumference of the enlarged diameter portion 246. The refrigerant stored in the enlarged diameter portion 246 flows into the radial through hole 241 formed in the stepped portion 247 due to centrifugal force and is pushed into the axial through hole 242. As a result, the refrigerant flows through the axial through hole 242 inside the rotor 20 from one end 20a to the other end 20b, cooling the inside of the rotor 20, especially the permanent magnet 25.

[0042] The end plates 201b of the other end 20b of the stator 15 have multiple openings 243 (see Figure 1) formed at positions corresponding to each axial through hole 242. The openings 243 are formed such that their cross-sectional area is greater than or equal to the cross-sectional area of ​​the axial through hole 242. Furthermore, the radially outer portions of the openings 243 are formed so that they are located radially further than the axial through holes 242.

[0043] With the opening 243 formed in this way, the refrigerant that has flowed through the axial through hole 242 and reached the other end 20b is quickly discharged from the opening 243 radially outward from the rotor 20 by the centrifugal force caused by the rotation of the rotor 20. This refrigerant is scattered toward the second coil end 152 of the stator 15, which is located radially outward from the other end 20b of the rotor 20, and cools the second coil end 152.

[0044] Furthermore, the base 12b near the other end 20b of the rotor 20 has a small-diameter portion 121b that fits into the annular recess 24b, and a flange portion 122b that extends radially outward from the small-diameter portion 121b (expanding in diameter) and is configured to face the end plate 201b of the rotor 20. From the small-diameter portion 121b to the flange portion 122, it is formed so that it gradually moves away from the rotor 20 as it moves radially outward. With the base 12b configured in this way, the refrigerant flowing out from the opening 243 moves radially outward while colliding with the small-diameter portion 121b and the flange portion 16b, and moves to the second coil end 152 of the stator 15.

[0045] Similarly, the base 12a near one end 20a of the rotor 20 has a small-diameter portion 121a that fits into the annular recess 24a, and a flange portion 122a that extends radially outward from the small-diameter portion 121a (expanding in diameter) and is configured to face the end plate 201a of the rotor 20. From the small-diameter portion 121a to the flange portion 122a, it is formed so that it gradually moves away from the rotor 20 as it moves radially outward. With the base 12 configured in this way, the refrigerant that has moved into the gap between one end 20a of the rotor 20 and the base 12a moves radially outward while colliding with the small-diameter portion 121a and the flange portion 16a, and moves to the first coil end 151 of the stator 15.

[0046] Next, the configuration for circulating the refrigerant in the motor 1 of this embodiment will be described.

[0047] Figure 7 is an explanatory diagram of the motor 1 of this embodiment, showing a configuration that includes a pump 40 for circulating refrigerant.

[0048] In motor 1, the refrigerant introduced into the housing 10 from the refrigerant inlet hole 14 cools the first coil end 151 of the stator 15, the rotor 20, and the second coil end 152 of the stator 15 through the annular recess 24a of the rotor 20. The refrigerant then flows down inside the housing 10 and is stored in the refrigerant storage section 18 located at the bottom of the housing 10.

[0049] A piping 30 and a pump 40 are connected to the refrigerant storage section 18. The piping 30 is connected to the refrigerant inlet hole 14 of the base 12. The pump 40 may be an electric pump driven by electricity, or a mechanical pump driven by the rotation of the rotating shaft 21 of the motor 1 transmitted by gears or the like.

[0050] The pump 40 draws up the refrigerant stored in the refrigerant storage section 18 and discharges the refrigerant through the piping 30 to the refrigerant inlet hole 14.

[0051] With this configuration, the pump 40 can be used to circulate the refrigerant for cooling the motor 1.

[0052] Figure 8 is an explanatory diagram of another example of the motor 1 of this embodiment, showing a configuration in which the motor 1 is equipped with a transmission 60.

[0053] The transmission 60 is connected to the rotating shaft 21 of the motor 1 and uses multiple gears 61 to change the speed of the motor 1's rotation (deceleration or acceleration) and output that rotation.

[0054] The transmission 60 has a refrigerant storage section 65 at its lower part. The refrigerant storage section 65 is in communication with the refrigerant storage section 18 of the motor 1, and the refrigerant stored in the refrigerant storage section 18 is also stored in the refrigerant storage section 65. Some of the gears 61 are immersed in the refrigerant storage section 65.

[0055] As motor 1 rotates, gear 61 of transmission 60 rotates, stirring up the refrigerant stored in refrigerant storage section 65. The refrigerant stirred up by gear 61 of transmission 60 flows into the refrigerant inlet hole 14 of base 12.

[0056] With this configuration, the rotation of the gear 61 of the transmission 60 can be used to circulate the coolant for cooling the motor 1.

[0057] As described above, in the embodiment of the present invention, the motor 1 (rotating electric machine) comprises a rotor 20, a stator 15 provided on the outer circumference of the rotor 20, and a housing 10 that houses the rotor 20 and the stator 15. The rotor 20 comprises a rotating shaft 21, a cylindrical portion 22 that encloses a permanent magnet 25, and a connecting portion 23 that connects the outer surface of the rotating shaft 21 and the inner surface of the cylindrical portion 22. The rotor 20 has an annular recess 24a that is formed by the rotating shaft 21, the cylindrical portion 22, and the connecting portion 23 and opens axially across the connecting portion 23. The housing 10 comprises a base 12 that rotatably supports the rotating shaft 21, and a refrigerant introduction hole 14 is provided around the base 12 for introducing refrigerant toward the annular recess 24a. The rotor 20 has a radial through-hole 241 that penetrates the cylindrical portion 22 radially in the annular recess 24a, and an axial through-hole 242 that communicates with the radial through-hole 241 and penetrates the inside of the rotor 20 axially. The refrigerant introduced into the annular recess 24a cools the permanent magnet 25 as it passes through the radial through-hole 241 and the axial through-hole 242.

[0058] With this configuration, an axial through-hole 242 is formed between the cylindrical portion 22 and the permanent magnet 25. As a result, the refrigerant introduced into the annular recess 24a from the refrigerant introduction hole 14 flows through the radial through-hole 241 and the axial through-hole 242 due to the centrifugal force caused by the rotation of the rotor 20, cooling the permanent magnet 25. This improves the cooling efficiency of the permanent magnet 25 of the rotor 20 by the refrigerant. By improving the cooling efficiency of the permanent magnet 25, demagnetization due to heat of the permanent magnet 25 can be suppressed, and the efficiency of the motor 1 can be improved.

[0059] Furthermore, in this embodiment, the inner circumferential surface of the cylindrical portion 22 has an enlarged diameter portion 246 on the connection portion side of the annular recess 24a, where the inner diameter is increased via a stepped portion 247, and the radial through hole 241 is formed in the stepped portion 247.

[0060] With this configuration, the refrigerant introduced into the annular recess 24a can be stored in the enlarged diameter section 246 due to centrifugal force, and the refrigerant can be more reliably guided into the radial through-hole 241.

[0061] Furthermore, in this embodiment, there is a gap between the base 12 and the rotor 20, and a portion of the refrigerant introduced from the refrigerant introduction hole 14 flows to the stator 15 through the gap. Therefore, the refrigerant introduced into the housing can be used not only to cool the rotor 20, but also to cool the stator 15 and the first coil end 151.

[0062] In this embodiment, the other end 20b of the permanent magnet 25 is provided with an end plate 201b, and the end plate 201b has an opening 243 into which the axial through hole 242 opens into the housing 10, the opening cross-sectional area of ​​the opening 243 is greater than or equal to the opening cross-sectional area of ​​the axial through hole 242, and at least a portion of the opening 243 is located radially outward from the axial through hole 242.

[0063] This configuration allows the refrigerant flowing through the axial through-hole 242 to quickly flow into the housing 10, and also facilitates the introduction of the refrigerant to the radially outer side of the rotor 20, i.e., the stator 15 side.

[0064] Furthermore, in this embodiment, the base 12 has a small-diameter portion 121b that fits into the inner circumference of the annular recess 24b, and a flange portion 122b that is erected radially outward on the axial end side of the small-diameter portion 121b.

[0065] With this configuration, the refrigerant flowing out from the opening 243 is moved radially outward by the centrifugal force caused by the rotation of the rotor 20, colliding with the flange portion 122b from the small diameter portion 121b of the base 12, and then moving towards the stator 15.

[0066] Furthermore, in this embodiment, permanent magnets 25 are arranged around the cylindrical portion 22, and axial through holes 242 are formed between the outer circumference of the cylindrical portion 22 and the inner circumference of the permanent magnets 25. The permanent magnets 25 have multiple magnetic poles in the circumferential direction, and the magnetic poles are arranged in a Halbach arrangement. Therefore, in the motor 1 to which the Halbach arrangement is applied, the permanent magnets 25 can be properly cooled by flowing a coolant in contact with the permanent magnets 25.

[0067] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0068] In this embodiment, the permanent magnet 25 is configured in which multiple segment magnets 251 are arranged in a Halbach arrangement, but it is not limited to this configuration. Any permanent magnet with a different pole configuration may be used, as long as an axial through hole can be placed between the inner circumference of a ring-shaped permanent magnet or a permanent magnet in which segment magnets are arranged in a ring, and the cylindrical portion 22. [Explanation of symbols]

[0069] 1: Motor, 10: Housing, 12: Base, 14: Refrigerant inlet, 15: Stator, 16: Flange, 20: Rotor, 20a: One end, 20b: Other end, 21: Rotating shaft, 22: Cylindrical part, 23: Connection part, 24a: Annular recess, 25: Permanent magnet, 40: Pump, 60: Transmission, 151: First coil end, 152: Second coil end, 201a: End plate, 201b: End plate, 241: Radial through hole, 242: Axial through hole, 243: Opening, 245: Small diameter part, 246: Enlarged diameter part, 247: Stepped part

Claims

1. A rotating electric machine comprising a rotor, a stator provided on the outer circumference of the rotor, and a housing that accommodates the rotor and the stator, The rotor comprises a rotating shaft, a cylindrical portion equipped with a permanent magnet, and a connecting portion connecting the outer circumferential surface of the rotating shaft and the inner circumferential surface of the cylindrical portion. The rotor comprises a space formed by the rotating shaft, the cylindrical portion, and the connecting portion, and includes an annular recess that opens axially across the connecting portion. The housing includes a base that rotatably supports the rotating shaft, The base is provided with a refrigerant inlet hole for introducing refrigerant toward the annular recess, The rotor has a radial through-hole in the annular recess that penetrates the cylindrical portion radially, and an axial through-hole that communicates with the radial through-hole and penetrates the interior of the rotor axially. The refrigerant introduced into the annular recess cools the permanent magnet by passing through the radial through-hole and the axial through-hole. The inner circumferential surface of the cylindrical portion has an enlarged diameter portion on the connecting portion side, where the inner diameter is wider via a stepped portion than the inner diameter on the opening side of the annular recess. The radial through hole is formed in the stepped portion of the enlarged diameter portion. Rotating electric machine.

2. A rotating electric machine according to claim 1, There is a gap between the base and the rotor. A portion of the refrigerant introduced through the refrigerant inlet flows to the stator via the gap. Rotating electric machine.

3. A rotating electric machine according to claim 1, The axial end of the permanent magnet is provided with an end plate, and the end plate has, The axial through hole has an opening that opens into the housing, The opening cross-sectional area of ​​the opening is greater than or equal to the opening cross-sectional area of ​​the axial through hole, and at least a portion of the opening is located radially outward from the axial through hole. Rotating electric machine.

4. A rotating electric machine according to claim 1, The base has a small-diameter portion that fits into the inner circumference of the annular recess near the end of the rotor, and a flange portion that is erected radially outward from the axial end side of the small-diameter portion. Rotating electric machine.

5. A rotating electric machine according to claim 1, The permanent magnet is arranged around the cylindrical portion, and the axial through hole is formed between the cylindrical portion and the permanent magnet. The permanent magnet has multiple magnetic poles in the circumferential direction, and the magnetic poles are arranged in a Halbach arrangement. Rotating electric machine.

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