Rotary electric machine

Abstract

To provide a rotary electric machine that does not require a high-output pump, with a refrigerant flow passage provided in a stator core.SOLUTION: The rotary electric machine includes a rotor and a stator. The stator has a stator core, a field coil arranged in a slot of the stator core, and a refrigerant flow passage. Furthermore, the refrigerant flow passage has a portion that is parallel to an axis of the rotor in at least a part thereof, and includes a rotary vane inside the parallel portion. At least a part of the rotary vane is formed of a magnetic material so that even a low-output pump can circulate a refrigerant.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a rotating electrical machine, and more particularly to a rotating electrical machine having a refrigerant flow path in a stator core.

Background Art

[0002] Since a rotating electrical machine uses a conductive material and a magnetic material, heat generation is inevitable, and efficient cooling is essential to improve the output torque. In particular, the rotating electrical machine of an electric vehicle (EV) is required to be small and high-performance in order to effectively utilize the limited space of the vehicle.

[0003] Patent Document 1 discloses that the stator can be efficiently cooled by flowing refrigerant inside a hollow bolt that penetrates the stator core and is fastened to the housing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the refrigerant has a lower magnetic permeability than the iron core, the refrigerant flow path in the stator core also causes a decrease in magnetic flux density, so the diameter of the refrigerant flow path cannot be increased. For this reason, the refrigerant flow path in the stator core is formed thin and the pressure loss increases, so a high-output and expensive pump is required.

[0006] The present invention has been made in view of such problems of the prior art, and an object thereof is to provide a rotating electrical machine having a refrigerant flow path in a stator core that does not require a high-output pump.

Means for Solving the Problems

[0007] As a result of intensive studies to achieve the above object, the present inventor has found that the above object can be achieved by providing a rotating vane formed of a magnetic material in the refrigerant flow path of the stator core, and has completed the present invention.

[0008] That is, the rotating electrical machine of the present invention includes a rotor and a stator, and the stator has a stator core, a field coil disposed in a slot of the stator core, and a refrigerant flow path. The refrigerant flow path has a portion parallel to the axis of the rotor at least in part, and a rotating vane is provided inside the parallel portion, and at least a part of the rotating vane is formed of a magnetic material.

Advantages of the Invention

[0009] According to the present invention, since a rotating vane formed of a magnetic material is provided in the refrigerant flow path of the stator core, a rotating electrical machine that does not require a high-output pump can be provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0011] The rotating electrical machine of the present invention will be described in detail. The rotating electrical machine 1 of the present invention includes a rotor 5 rotatably mounted on a housing and a stator 4 disposed on the outer peripheral side of the rotor 5.

[0012] As shown in FIG. 1, the stator 4 has a stator core 41 and a coil wire 42. The coil wire is inserted into the slots of the stator core 41 and extends in the axial direction. Then, it is folded back at the axial end of the stator core 41 and inserted into the slot again, and this is repeated a plurality of times to form a field coil wound in the circumferential direction, and coil ends 43 are formed at both ends of the stator core.

[0013] The stator 4 further includes a refrigerant flow path 2. The refrigerant flowing through the refrigerant flow path 2 cools the stator 4 by circulating between the stator 4 and an external heat exchanger.

[0014] As the refrigerant, in addition to liquids such as water and oil, gases such as air can also be used.

[0015] The refrigerant flow path 2 has a parallel portion 21 extending parallel to the axis of the rotor 5 from one end to the other end of the stator core 41. The parallel portion 21 has a circular cross section and includes a rotating vane 3 inside.

[0016] As shown in FIG. 2, the rotating vane 3 has spiral blades 32, that is, screws, around a central axis 31. Also, at least a part of it is formed of a magnetic material, and this magnetic material forms a magnet in the rotating electrical machine where the direction of the magnetic field is orthogonal to the central axis 31.

[0017] Thus, since a part of the rotating vane 31 forms a magnet, when the rotor 5 rotates, as shown in FIG. 3, it rotates in synchronization with the change in its magnetic field and forms a screw pump that transfers the refrigerant in the axial direction together with the refrigerant flow path 2.

[0018] In the rotating electric machine of the present invention, the parallel portion 21 of the refrigerant flow path functions as a screw pump. Since the rotational speed of this screw pump changes according to the rotational speed of the rotor 5, it can rotate at high speed and transfer a large amount of refrigerant during high-speed rotation when the heat generation amount increases.

[0019] Therefore, even in a narrow refrigerant flow path with a large pressure loss, a sufficient amount of refrigerant can flow, eliminating the need for a high-output external pump and enabling refrigerant circulation even if the external pump has low output.

[0020] When the rotating vane 3 transfers refrigerant, it receives an axial reaction force from the refrigerant. However, since the magnetic body is attracted by the magnetic force of the rotor 5 and returns to a predetermined position, it is not necessary to provide a bearing for the rotating vane in the refrigerant flow path 2 to restrict axial movement, preventing pressure loss due to bearing installation and facilitating production.

[0021] The magnetic body is preferably a permanent magnet. When the magnetic body has a configuration in which a plurality of N poles and S poles are alternately arranged in the circumferential direction as shown in FIG. 4, the rotational speed of the rotating vane with respect to the rotational speed of the rotor is higher than that of a permanent magnet having one N pole and one S pole, and the amount of refrigerant transferred can be increased.

[0022] The entire rotating vane 3 may be formed of a magnetic body, or the blades 32 may be formed of resin and the central shaft 31 may be formed of a magnetic body, and can be selected according to the required refrigerant transfer ability.

[0023] When the entire rotating vane is formed of a magnetic body, it rotates following the change in the magnetic field due to the rotation of the rotor and is less likely to become out of tune, so the blade portion can be enlarged, increasing the amount of refrigerant transferred. Also, by forming the blades 32 of resin, weight reduction can be achieved.

[0024] It is preferable that the radial tip of the blade 32 of the rotating vane 3 abuts against the inner peripheral surface of the refrigerant flow path 2 over the entire area. Since the tip of the blade 32 abuts against the refrigerant flow path 2 and a closed space is formed between the inner peripheral surface of the refrigerant flow path and the blade, backflow of the refrigerant can be prevented, and the transfer efficiency of the refrigerant, that is, the cooling efficiency, is improved.

[0025] Further, if a solid lubricant layer is formed on the inner peripheral surface of the refrigerant flow path 2 with which the blade 32 abuts and the contact portion of the blade, wear due to the rotational sliding of the blade can be suppressed, and the refrigerant can be efficiently transferred over a long period of time.

[0026] Examples of the solid lubricant include solid lubricants such as molybdenum disulfide (MoS2), tungsten disulfide (WS2), and polytetrafluoroethylene (PTFE), as well as carbon-based solid lubricants such as graphite, fullerene (C 60 ), carbon nanotube (CNT), and DLC (diamond-like carbon).

[0027] The refrigerant flow path 2 can be formed by a through-hole that axially penetrates the stator core 41. The through-hole is provided on the outer peripheral side of the slot. By providing the through-hole outside the slot, it is possible to suppress a decrease in magnetic flux density and transfer the refrigerant using the leakage magnetic flux.

[0028] In this way, since the refrigerant flows through the stator core 41, heat can be removed near the field coil of the stator where cooling is difficult, and the cooling efficiency is improved.

[0029] As shown in FIG. 5, it is preferable to provide a plurality of through-holes serving as the refrigerant flow path 2 at equal intervals in the circumferential direction. Thereby, cooling unevenness in the circumferential direction can be reduced.

[0030] Also, as shown in Fig. 6, the above refrigerant flow path can also be formed by forming the field coil with the coil wire 42 of the hollow tube. By forming the field coil with a hollow coil wire and flowing the refrigerant through the coil wire, the field coil of the stator, which is difficult to cool, can be directly cooled, improving the cooling efficiency.

Explanation of Signs

[0031] 1 Rotating electrical machine 2 Refrigerant flow path 21 Parallel part 3 Rotating vane 31 Central axis 32 Blade 4 Stator 41 Stator core 42 Coil wire 43 Coil end 5 Rotor

Claims

1. A rotating electrical machine comprising a rotor and a stator, wherein the stator has a stator core, a field coil disposed in a slot of the stator core, and a refrigerant flow path, the refrigerant flow path has at least a part parallel to the axis of the rotor, and a rotating vane is provided inside the parallel part, and at least a part of the rotating vane is formed of a magnetic material. The rotating electrical machine is characterized by this.

2. The radially outer tip of the blade of the rotating vane abuts against the inner peripheral surface of the parallel part, and the rotating electrical machine according to Claim 1 is characterized by having a solid lubricant layer on the inner peripheral surface of the parallel part and / or the contact part of the blade.

3. The rotating electrical machine according to Claim 1 is characterized in that the blade of the rotating vane is formed of resin.

4. The rotating electrical machine according to Claim 1 is characterized in that the parallel part of the refrigerant flow path is a through hole formed in the stator core.

5. The field coil is formed of a coil wire of a hollow tube, and the rotating electrical machine according to Claim 1 is characterized in that the refrigerant flow path is formed inside the coil wire.

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