Rotary electric machine

Abstract

To provide a rotary electric machine capable of uniformly cooling a coil end of a stator to a peripheral direction.SOLUTION: In an air cooling type rotary electric machine that circulates a cooling air into a housing, the housing includes: two annular distribution channels; and a circulation flow channel connecting the two annular distribution channels. Each annular distribution channel is arranged to both ends of a shaft direction of the stator so as to surround an outer periphery of a coil end projected from an end part of a shaft direction of the stator, and each of the plurality of distribution channels is formed so that a ventilation hole opened toward the coil end is arranged to a peripheral direction. The rotor includes a cooling air channel penetrated from one end side of the shaft direction to the other end side. A fun rotated with the rotor is provided to the other end side of the shaft direction of the rotor. The fun blows the cooling air toward the other end side from the one end side of the cooling air channel by sucking the cooling air from the cooling air channel, and the cooling air is blown toward an inner side of the coil end, and the cooling air is circulated via the ventilation air hole.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine, and more particularly to an air-cooled rotating electric machine that is cooled by flowing cooling air inside a housing. [Background technology]

[0002] Rotating electric motors for electric vehicles (EVs) are required to be small and high-performance in order to make effective use of the limited space inside the vehicle. Since such rotating electric motors use conductive and magnetic materials, heat generation is unavoidable, and efficient cooling is essential to improve output torque.

[0003] In particular, at the coil ends of the stator, the coil wire that protrudes axially from the slots turns back and heads back into the slots, and the coil wires are arranged in an intertwined manner, which easily disrupts the flow of cooling air and makes it difficult to direct the cooling air to the desired location for efficient cooling.

[0004] Patent Document 1 discloses a rotating electric machine that cools the stator coil ends by providing a straightening plate so that cooling air flowing in the axial direction inside the rotor flows toward the coil ends of the stator. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-185431 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the rotating electric machine described in Patent Document 1 has only one outlet for cooling air into the housing and one outlet for cooling air that has passed through the housing. Therefore, while the cooling air flows easily near the outlet and outlet, the cooling air stagnates in areas far from the outlet and outlet and does not flow easily, making it difficult to cool the coil ends uniformly.

[0007] The present invention has been made in consideration of the problems associated with the conventional technology, and has an object to provide a rotating electric machine capable of uniformly cooling the coil ends of the stator in the circumferential direction. [Means for solving the problem]

[0008] As a result of extensive research into achieving the above-mentioned objective, the inventors discovered that the above-mentioned objective could be achieved by arranging annular distribution passages so as to surround the outer periphery of the coil ends, and forming multiple ventilation holes in the distribution passages that open toward the coil ends, arranged in a circumferential direction, thus completing the present invention.

[0009] That is, the rotating electric machine of the present invention is an air-cooled rotating electric machine in which cooling air is circulated within a housing that accommodates a rotor and a stator. The housing has two annular distribution passages and a circulation passage connecting the two distribution passages, the distribution passages are disposed at both axial ends of the stator so as to surround outer peripheries of coil ends protruding from axial ends of the stator, and each distribution passage has a plurality of ventilation holes arranged in a circumferential direction and opening toward the coil ends, The rotor has a cooling air flow passage that penetrates from one axial end to the other end, and a fan that rotates together with the rotor is provided on the other axial end of the rotor, and the fan draws in cooling air from the cooling air flow passage and flows the cooling air from one end to the other end of the cooling air flow passage, while blowing the cooling air toward the inside of the coil end, circulating the cooling air through the ventilation holes. Effect of the Invention

[0010] According to the present invention, a distribution flow passage in which a plurality of ventilation holes opening toward the coil end are arranged in a circumferential direction is arranged in a circular ring shape surrounding the outer periphery of the coil end, thereby making it possible to provide a rotating electric machine that can uniformly cool the coil ends of the stator in the circumferential direction. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is an axial cross-sectional view of a rotating electric machine. [Diagram 2] 2 is a cross-sectional view of the rotating electric machine taken along a plane of a vent hole in a direction perpendicular to the axis. [Diagram 3] FIG. 4 is an enlarged view of a connection portion between a circulation flow path and a distribution flow path. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The rotating electric machine of the present invention will now be described in detail. The rotating electric machine has a rotor 3 and a stator 2 housed in a housing 1, and is an air-cooled rotating electric machine in which cooling air is circulated within the housing.

[0013] The stator 2 has a coil wire inserted into the slots of its stator core 21, and this coil wire protrudes from the axial end of the stator core 21, turns back, and is again inserted into the slot. This is repeated multiple times at both ends of the stator core 21 to form a coil, and at both ends of the stator core, coil ends 22 protruding from the axial end are formed.

[0014] As shown in FIG. 1, the rotor 3 has a cooling air flow passage 311 passing through from one axial end side to the other axial end side, and is mounted inside the stator 2 so as to be freely rotatable.

[0015] A centrifugal fan 321 is fixed to the other axial end of the rotor 3, and rotates together with the rotor to generate cooling air.

[0016] In the present invention, the centrifugal fan 321 is provided in a direction in which the cooling air is sucked from the cooling air flow path 311 by the rotation of the rotor.

[0017] As a result, when rotor 3 rotates, gas in the cooling air flow path is sucked into centrifugal fan 321, as shown by the arrow in Figure 1, and cooling air flows from one end of cooling air flow path 311 to the other end, cooling rotor 3.

[0018] Furthermore, since the centrifugal fan 321 generates an airflow in a direction perpendicular to the rotation axis, the cooling air can be blown directly against the inside of the coil ends 22 located radially outward of the centrifugal fan to cool them.

[0019] However, in a rotating electric machine of a circulation type in which the cooling air flow path is closed, i.e., in the case of a machine in which the cooling air that has flowed between the coil wires of the coil end 22 on the other end side is circulated within the housing by being directed to one end side via a circulation flow path, if there is only one outlet and one inlet of the circulation flow path, the cooling air cannot be made to flow uniformly in the circumferential direction of the coil end.

[0020] That is, a pressure difference occurs between near the outlet or inlet of the circulation flow path provided in the housing 1 and a position distant from the outlet or inlet.

[0021] Furthermore, since the rotation axis 32 of the rotor 3 is located at the center of the coil end 22, which is equidistant from any circumferential position of the coil end 22, it is not possible to provide an outlet or inlet of the circulation flow path at the radial center of the rotor. If there is only one outlet or inlet, a pressure difference will inevitably occur in the circumferential direction, making it difficult to cool the coil end 22 uniformly.

[0022] In the present invention, as shown in Figures 1 and 2, a circular distribution passage 11 that surrounds the outer periphery of the coil end is provided between the circulation passage 12 and the coil end 22, and a plurality of ventilation holes 111 that open toward the coil end 22 are formed in the distribution passage and arranged in the circumferential direction, and cooling air is circulated through these ventilation holes 111.

[0023] Note that the arrows in FIG. 2 indicate the state in which the cooling air enters the housing, and the direction of the arrows is reversed when the cooling air exits the housing 1.

[0024] As a result, the cooling air flowing radially outward between the coils of the coil end 22 on the other end side enters the distribution flow passage 11 from the ventilation hole 111 arranged circumferentially that is easiest to enter, and then enters the circulation flow passage 12 via the distribution flow passage 11, thereby reducing the circumferential pressure difference near the coil end.

[0025] In this way, the cooling air flowing through the cooling passage 311 of the rotor 3 spreads radially toward the ventilation holes 111 of the distribution passage 11 provided on the outer periphery of the coil end 22, and each of the spreading flows in approximately a constant direction without bending or stagnating, so that the coil end 22 on the other end side can be uniformly cooled without the need for a straightening plate.

[0026] In addition, the rotating electric machine of the present invention has a circular distribution passage 11 on one end side similar to that on the other end side, and the cooling air that flows through the circulation passage 12 via the distribution passage 11 on the other end side is cooled in a heat exchanger 4 that is provided as necessary, and flows through the distribution passage 11 on the one end side.

[0027] As shown in FIG. 2, the distribution passage 11 on one end side is also arranged to surround the outer periphery of the coil end 22 on one end side, similar to the other end side, and multiple ventilation holes 111 opening toward the coil end 22 on one end side are formed lined up in the circumferential direction.

[0028] Therefore, cooling air is blown out from a plurality of ventilation holes 111 arranged around the entire circumference of the outer periphery of the coil end 22 on one end side toward the outside of the coil end 22 on the one end side, and is sucked into the cooling flow passage 311 of the rotor.

[0029] In this way, in the present invention, cooling air flows in a constant direction from the entire radial outside of the coil end on one end toward the inside, so that the coil end on one end can also be uniformly cooled.

[0030] The cooling air that has cooled the coil ends on one end is drawn into centrifugal fan 321 on the other end through cooling air flow path 311 formed in the rotor, and circulates within the housing.

[0031] In addition to the centrifugal fan, an axial fan 322 may be provided which is fixed to one axial end of the rotor and rotates together with the rotor, so that the cooling air which has cooled the coil end 22 on the one end side can be accelerated in the direction of the cooling air flow path of the rotor.

[0032] The opening diameter of each vent hole formed in the distribution flow path is preferably smaller than the flow path diameter of the connection part 13 between the distribution flow path 11 and the circulation flow path 12 .

[0033] If the opening diameter of the ventilation hole 111 is larger than the flow path diameter of the connection part 13, the air will pass through the ventilation hole closest to the connection part, and it will be difficult for the air to pass through the ventilation hole farther from the connection part.

[0034] By making the opening diameter of the ventilation holes smaller than the flow path diameter of the connection part and restricting the flow rate of the cooling air flowing through the ventilation holes, the cooling air flows throughout the entire distribution flow path 11, and the cooling air can flow in and out through all the ventilation holes lined up in the circumferential direction, thereby uniformly cooling the coil ends in the circumferential direction. In addition, the flow speed of the cooling air passing through the ventilation holes can be increased, improving cooling efficiency.

[0035] It is also preferable that the opening diameter of the ventilation hole increases with increasing distance from the connection portion. By adjusting the opening diameter of the ventilation holes according to the distance from the connection portion, the flow rate of cooling air flowing through each ventilation hole can be made equal, making it possible to uniformly cool the coil ends in the circumferential direction.

[0036] When the ventilation hole closest to the connection portion is located at the same circumferential position as the connection portion, it is preferable to have a wall 131 covering the ventilation hole so that the closest ventilation hole is not visible when the connection portion 13 is viewed radially, as shown in Figure 3.

[0037] The wall 131 is supported by the housing 1 at both axial ends and is formed so that the cooling air flows around both circumferential ends of the wall.

[0038] This causes the cooling air to hit the wall 131, preventing it from flowing linearly between the nearest ventilation hole and the circulation flow path, and the cooling air also flows through ventilation holes that are farther away from the connection portion 13.

[0039] The connection parts with the annular distribution flow path and circulation flow path can be formed by making the housing 1 a double structure of an inner housing 1b and an outer housing 1a, and matching a groove formed on the outer diameter side of the inner housing 1b with the inner diameter side of the outer housing 1a, and the inner housing and the outer housing can be formed by casting.

[0040] The rotating electric machine of the present invention can be provided with a cooling water flow path for circulating cooling water in addition to the flow path for circulating cooling air. This cooling water flow path is provided between the inner diameter side of the outer housing 1a and the outer diameter side of the inner housing 1b, parallel to the distribution flow path 11.

[0041] At least one of the outer housing and the inner housing preferably has a fin protruding into the distribution passage.

[0042] The housing is often made of aluminum, which has high thermal conductivity, and heat is exchanged between the cooling water and the cooling air through the housing, thereby cooling the cooling air that has been heated at the other end, improving the cooling efficiency of the coil end at one end. [Explanation of symbols]

[0043] 1. Housing 1a Outer housing 1b Inner housing 11 Distribution channel 111 Ventilation hole 12 Circulation flow path 13 Connection 131 Wall 2 Stator 21 Stator core 22 Coil end 3 Rotor 31 Rotor core 311 Cooling air flow path 32 Axis 321 Centrifugal Fan 322 Axial Fan 4 Heat exchanger

Claims

1. An air-cooled rotating electric machine that circulates cooling air within a housing that accommodates a rotor and a stator, The housing has two annular distribution flow paths and a circulation flow path connecting the two distribution flow paths, the distribution flow passages are disposed at both axial ends of the stator so as to surround outer peripheries of coil ends protruding from axial ends of the stator, Each of the distribution passages has a plurality of ventilation holes arranged in the circumferential direction and opening toward the coil end, The rotor has a cooling air flow path extending from one axial end to the other axial end, a fan that rotates together with the rotor is provided on the other axial end side of the rotor, the fan draws in cooling air from the cooling air flow passage and causes the cooling air to flow from one end side to the other end side of the cooling air flow passage, and blows the cooling air toward an inner side of the coil end, A rotating electric machine characterized in that the cooling air is circulated through the ventilation holes.

2. 2. The rotating electric machine according to claim 1, wherein an opening diameter of the ventilation hole is smaller than a flow passage diameter at a connection portion between the distribution flow passage and the circulation flow passage, and increases with increasing distance from the connection portion.

3. 2. The rotating electric machine according to claim 1, wherein an axial flow fan that rotates together with the rotor is provided on one end side of the rotor.

4. the ventilation hole closest to the connection portion is located at the same position in the circumferential direction as the connection portion, the connection portion has a wall that covers the nearest ventilation hole when viewed in a radial direction, The wall is supported at both axial ends by the housing; 3. The rotating electric machine according to claim 2, wherein the cooling air flows around both circumferential ends of the wall.

5. The housing further has a cooling water flow passage on an outer diameter side of the distribution flow passage, 5. The rotating electric machine according to claim 4, further comprising a fin protruding into the distribution passage on the side of the cooling water passage facing the distribution passage.

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