Cooling structure for rotating electrical machines

Abstract

To provide a cooling structure for a rotary electric machine capable of efficiently cooling a lower side region in a vertical direction of a coil end portion and suppressing temperature unevenness in the coil end portion.SOLUTION: A cooling structure for a rotary electric machine includes a housing cover attached to a housing that accommodates the rotary electric machine and is arranged to face a coil end portion of the rotary electric machine. The housing cover includes: an inner wall portion that has a bearing portion for receiving a rotary shaft of the rotary electric machine, is axially spaced apart from the coil end portion, and guides cooling oil supplied from a vertically upper side of the rotary electric machine downward along a plane that intersects the rotary shaft; an oil guide that is attached to the inner wall portion below the bearing portion in the vertical direction and guides the cooling oil guided by the inner wall portion to an inner circumference of the coil end portion on the vertically lower side; and a cooling portion that is thermally connected to the inner wall portion and cools the cooling oil guided the inner wall portion.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cooling structure for a rotating electrical machine. [Background technology]

[0002] 2. Description of the Related Art Conventionally, rotating electric machines have been known that are provided with a cooling structure that brings cooling oil into contact with coil ends of a stator in order to increase the efficiency of cooling the coils wound around a stator core.

[0003] In this type of rotating electric machine, the vertically upper region of the coil end where cooling oil is supplied is in contact with the cooling oil at a higher temperature in the vertically lower region, so heat exchange is not promoted and temperature unevenness is likely to occur in the coil end.For this reason, a cooling structure has been proposed in which ridges are formed on the wall surface of the cover part facing the coil end, and the ridges guide the cooling oil collected on the wall surface side so that it drips below the coil end (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-65384 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the cooling structure of Patent Document 1, the temperature of the cooling oil guided to the underside of the coil end portion via the ridges of the cover portion is equal to or higher than the temperature of the cooling oil discharged from the coolant supply portion. Also, the cooling oil guided to the ridges of the cover portion and flowing to the underside is only a portion of the cooling oil sprayed from the upper side of the coil end portion. Therefore, the cooling effect of the cooling structure of Patent Document 1 on the underside of the coil end portion is limited, and there is still room for improvement in suppressing temperature unevenness between the upper and lower sides of the coil end portion.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and provides a cooling structure for a rotating electric machine that can efficiently cool the vertically lower region of the coil end portion and suppress temperature unevenness in the coil end portion. [Means for solving the problem]

[0007] One aspect of the present invention is a cooling structure for a rotating electric machine, the cooling structure including a housing cover attached to a housing that accommodates the rotating electric machine and disposed opposite a coil end portion of the rotating electric machine, the housing cover having a bearing portion that receives a rotating shaft of the rotating electric machine and spaced apart in the axial direction from the coil end portion, an inner wall portion that guides cooling oil supplied from the vertical upper side of the rotating electric machine to the lower side along a plane intersecting the rotating shaft, an oil guide attached to the inner wall portion vertically lower than the bearing portion and that guides the cooling oil guided by the inner wall portion to an inner periphery vertically below the coil end portion, The piping is arranged in a serpentine manner so as to extend horizontally within a plane along the inner wall portion, Thermally connected to the inner wall Equipped with refrigerant piping and a cooling portion that cools the cooling oil guided to the inner wall portion.

[0008] above The cooling portion may be disposed in a region of the inner wall portion vertically above the bearing portion. Effect of the Invention

[0009] The cooling structure for a rotating electric machine according to one aspect of the present invention can efficiently cool the area vertically below the coil end portion, thereby suppressing temperature unevenness in the coil end portion. [Brief description of the drawings]

[0010] [Figure 1] 1 is a vertical cross-sectional view showing an example of a rotating electric machine according to an embodiment of the present invention; [Diagram 2] 2 is a perspective view of an example of a housing cover portion of the embodiment. FIG. [Diagram 3] FIG. [Figure 4] 6A and 6B are diagrams illustrating the flow of a refrigerant inside the housing cover portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiments, in order to make the description easier to understand, structures and elements other than the main parts of the present invention will be described in a simplified or omitted manner. In addition, in the drawings, the same elements are given the same reference numerals. Note that the shapes, dimensions, etc. of each element shown in the drawings are shown only for illustrative purposes, and do not represent the actual shapes, dimensions, etc.

[0012] Fig. 1 is a vertical cross-sectional view showing an example of a rotating electric machine according to the present embodiment. The rotating electric machine 1 according to the present embodiment is an inner rotor type motor, and includes a rotor 2 and a stator 3. Fig. 1 partially shows the non-load side of the rotating electric machine 1.

[0013] The rotor 2 is, for example, a magnet-embedded type or a surface magnet type rotor. A shaft 4 is fitted into the center of the rotor 2 so as to penetrate the iron core along the rotation axis AX. In the following description, the circumferential direction about the rotation axis AX will be simply referred to as the circumferential direction, and the radial direction about the rotation axis AX will be simply referred to as the radial direction.

[0014] The stator 3 has a cylindrical stator core, and is arranged concentrically on the outer periphery of the rotor 2 with a small air gap between them. A plurality of slots (not shown) are formed along the axial direction on the inner periphery of the stator 3, and coils are wound in the slots. The coil end portions 5 of the coils protrude from the stator 3 at both axial ends of the stator 3, and form an annular shape in the circumferential direction.

[0015] In the rotating electric machine 1, the magnetic field of the stator 3 is switched in sequence by controlling the current through the coils, which generates an attractive or repulsive force with the magnetic field of the rotor 2. This causes the rotor 2 and the shaft 4 to rotate, driving the rotating electric machine 1. At this time, the coils generate heat due to the passage of current.

[0016] Moreover, the rotating electric machine 1 of this embodiment is accommodated in a rotating electric machine housing having a housing main body 6 and a housing cover portion 7. Both the housing main body 6 and the housing cover portion 7 are manufactured by casting.

[0017] The housing body 6 of the rotating electrical machine housing is a case having a cylindrical space that is open on one axial side and the other axial side. The rotor 2 and the stator 3 are disposed in the cylindrical space of the housing body 6. For example, the stator 3 is fitted to the inner periphery of the housing body 6, and the housing body 6 is attached so as to cover the outer periphery of the stator 3.

[0018] Housing cover portions 7 are attached to one and the other sides of the housing body 6 at a distance from the coil end portion 5 in the axial direction, and openings on both sides of the housing body 6 are closed by the housing cover portions 7. The shaft 4 is rotatably supported by a bearing 7b provided in a bearing portion 7a of the housing cover portion 7. Note that Fig. 1 only shows the configuration of the anti-load side housing cover portion 7, and the load side housing cover portion is not shown.

[0019] 1, on the anti-load side (one side) of the rotating electrical machine housing, a circuit housing 8 is attached to a housing cover part 7. The circuit housing 8 accommodates therein a control board 9 of an inverter circuit that converts DC voltage from an external power source (not shown) into AC voltage and supplies it to the coil.

[0020] The rotating electrical machine housing also has a discharge oil passage 11 for oil cooling the coil end portion 5. The discharge oil passage 11 is an oil passage through which oil cooled by an oil cooler (not shown) flows. The discharge oil passage 11 is disposed above the stator 3 in FIGS. 1 and 2, and extends in the axial direction within the housing main body 6 and the housing cover portion 7. A first inlet hole 12 and a second inlet hole 13 branching off from the discharge oil passage 11 are formed in the housing cover portion 7.

[0021] The first inlet hole 12 is formed to extend radially downward from the end of the discharge oil passage 11, and communicates with the inside of the housing cover portion 7 at a position facing the outer circumferential surface of the coil end portion 5. The first inlet hole 12 serves to spray oil from the discharge oil passage 11 to the coil end portion 5 from above.

[0022] The second inlet hole 13 is formed at an end of the discharge oil passage 11 inclined downward in the axial direction, and communicates with the inside of the housing cover part 7 at a position facing the inner wall surface 14 of the housing cover part 7. The second inlet hole has the function of guiding oil from the discharge oil passage 11 toward the inner wall surface 14 of the housing cover part 7 that faces the coil end portion 5.

[0023] 2, an oil guide 15 is attached to the inner wall surface 14 of the housing cover portion 7, which guides oil flowing along the inner wall surface 14 to the lower region of the coil end portion 5. The oil guide 15 is a flat plate-shaped member bent in a V shape so as to form a downward convexity toward the center, and is attached below the bearing portion 7a. The oil guide 15 is disposed within the housing cover portion 7 so that one long side is in contact with the inner wall surface 14 and the other long side faces the coil end portion 5.

[0024] 3 is a plan view of the oil guide 15. A first auxiliary guide portion 15a and a second auxiliary guide portion 15b are provided on the upper surface of the other long side of the oil guide 15. The first auxiliary guide portion 15a is formed in the center of the oil guide 15. The second auxiliary guide portions 15b are formed on both sides in the longitudinal direction of the oil guide 15, separated by the first auxiliary guide portion 15a in the center.

[0025] The first auxiliary guide portion 15a is a protrusion disposed to extend in an oblique direction with respect to the longitudinal direction of the oil guide 15 so that one side of the oil guide 15 is closer to the center than the other side. The first auxiliary guide portion 15a guides the oil flowing on the upper surface of the oil guide 15 so that it drips onto the coil end portion 5 near the central portion of the oil guide. The second auxiliary guide portion 15b is a protrusion extending in the longitudinal direction of the oil guide 15 along the edge of the other side of the oil guide 15. The second auxiliary guide portion 15b prevents oil from spilling to the other side at locations other than the central portion of the oil guide 15.

[0026] The vicinity of the bottom surface of the rotating electrical housing functions as an oil pan in which oil that has exchanged heat with the coil end portion 5 is stored, and the housing body 6 is provided with a suction outlet (not shown) for sucking out the oil stored in the oil pan. The suction outlet of the housing body 6 is connected to a flow path that communicates with an oil pump (not shown).

[0027] Next, the configuration of the housing cover portion 7 of the rotating electrical machine housing will be described. The housing cover part 7 is configured in a box shape. A first cooling part 21, a second cooling part 22, and a resolver 23 are accommodated in the internal space of the housing cover part 7 formed between the inner wall surface 14 and the circuit housing 8. The resolver 23 is a detector that detects the rotation angle of the shaft 4, and is attached to the anti-load side of the shaft 4.

[0028] The first cooling unit 21 is disposed in a region vertically above the bearing portion 7a of the housing cover portion 7, and is a device for cooling the oil flowing on the inner wall surface 14 of the housing cover portion 7. As shown in FIG. 4, the first cooling unit 21 has a refrigerant pipe 21a thermally connected to the inner wall surface 14 of the housing cover portion 7. The refrigerant pipe 21a of the first cooling unit 21 is connected to a refrigerant inlet 24 that receives a refrigerant supplied from the outside of the housing cover portion 7. The refrigerant pipe 21a is disposed in a meandering manner so that the pipe extends in a horizontal direction perpendicular to the vertical direction within a plane along the inner wall surface 14 of the housing cover portion 7. The second cooling unit 22 is connected to the downstream side of the refrigerant pipe 21a of the first cooling unit 21. As a result, the refrigerant flowing through the refrigerant pipe 21a exchanges heat with the oil flowing along the inner wall surface 14 of the housing cover portion 7, thereby cooling the oil.

[0029] The second cooling unit 22 is disposed on the circuit housing 8 side of the housing cover unit 7, and is a device for cooling the control board 9 disposed inside the circuit housing 8. The second cooling unit 22 is thermally connected to the wall surface of the housing cover unit 7 on the circuit housing 8 side, and cools the control board 9 by flowing the refrigerant received from the first cooling unit 21. The downstream side of the second cooling unit 22 is connected to a refrigerant outlet 25 that discharges the refrigerant to the outside of the housing cover unit 7.

[0030] The flow of oil in the rotating electrical machine 1 of this embodiment will be described below. Oil stored in an oil pan of the housing of the rotating electrical machine is sucked out from a suction port (not shown) by driving an oil pump, cooled in an oil cooler (not shown), and then sent to a discharge oil passage 11 located on the upper side of the housing of the rotating electrical machine. In the discharge oil passage 11, the oil flows to one side (anti-load side) and the other side (load side) in the axial direction, but the following explanation will focus on the oil flowing toward one side of the discharge oil passage 11.

[0031] The oil flowing on one side of the discharge oil passage 11 branches into a first inlet hole 12 and a second inlet hole 13 at the end of the discharge oil passage 11. The oil that flows into the first inlet hole 12 is sprayed onto the coil end portion 5 from above, and flows downward around the outer periphery of the coil end portion 5 from both the left and right directions. As a result, the oil that comes into contact with the coil end portion 5 absorbs heat, thereby cooling the coil end portion 5. Here, the temperature of the oil sprayed onto the coil end portion 5 from above increases as it flows downward due to heat exchange. Therefore, the oil sprayed onto the coil end portion 5 from above cools the upper region of the coil end portion 5 more effectively than the lower region of the coil end portion 5.

[0032] On the other hand, the oil that flows into the second inlet hole 13 is guided to the inner wall surface 14 of the housing cover portion 7, and flows downward along the inner wall surface 14 of the housing cover portion 7. Since the first cooling portion 21 is disposed above the bearing portion 7a on the inner wall surface 14 of the housing cover portion 7, the oil that flows along the inner wall surface 14 of the housing cover portion 7 is cooled by heat exchange with the first cooling portion 21. The cooled oil then reaches the oil guide 15, and the oil guided to the center of the oil guide 15 drips to the other side. As a result, the oil that drips from the oil guide 15 comes into contact with the inner periphery of the coil end portion 5 in the region below the coil end portion 5, and removes heat.

[0033] The oil that has passed through the inner wall surface 14 of the housing cover portion 7 and has been cooled by the first cooling portion 21 is dripped directly onto the lower region of the coil end portion 5 by the oil guide 15, without coming into contact with the upper region of the coil end portion 5. This improves the cooling efficiency of the lower region of the coil end portion 5, thereby suppressing temperature unevenness between the upper and lower regions of the coil end portion 5.

[0034] Furthermore, the oil running down the inner wall surface 14 of the housing cover portion 7 is cooled by the first cooling portion 21, and therefore its temperature is lower than oil not cooled by the first cooling portion 21 (oil sprayed from above). Therefore, according to this embodiment, even if the flow rate of oil running down the inner wall surface 14 of the housing cover portion 7 is small, the region below the coil end portion 5 can be efficiently cooled.

[0035] In addition, the oil sprayed from above onto the coil end portion 5 and the oil dripped onto the inner circumference of the coil end portion 5 by the oil guide 15 both join and are stored in the oil pan, and are sent out again towards the oil cooler by driving the oil pump. In this embodiment, because part of the oil is also cooled by the first cooling section 21, the temperature of the oil stored in the oil pan is lower than in the case where the first cooling section 21 is not present. Therefore, in this embodiment, the load on the oil cooler that cools the oil from the oil pan is also reduced, and costs can be reduced by reducing the capacity of the oil cooler.

[0036] The present invention is not limited to the above-described embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.

[0037] In the above embodiment, a configuration example of a motor has been described as an example of a rotating electric machine, but the rotating electric machine of the present invention can also be applied to an oil-cooled generator.

[0038] In the above embodiment, an example of the configuration of the anti-load side housing cover part has been described, but the load side housing cover part is configured similarly to the anti-load side. Note that the load side housing cover part differs from the anti-load side housing cover part in that it does not have the second cooling part.

[0039] In addition, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0040] Reference Signs List 1... rotating electric machine, 2... rotor, 3... stator, 4... shaft, 5... coil end portion, 6... housing main body, 7... housing cover portion, 7a... bearing portion, 7b... bearing, 11... discharge oil passage, 12... first inlet hole, 13... second inlet hole, 14... inner wall surface, 15... oil guide, 21... first cooling portion, 22... second cooling portion

Claims

1. A cooling structure for a rotating electric machine including a housing cover attached to a housing that accommodates a rotating electric machine and disposed opposite a coil end portion of the rotating electric machine, The housing cover includes: an inner wall portion having a bearing portion for receiving a rotating shaft of the rotating electric machine and spaced apart in the axial direction from the coil end portion, the inner wall portion guiding cooling oil supplied from an upper side of the rotating electric machine in a vertical direction to a lower side along a plane intersecting the rotating shaft; an oil guide attached to the inner wall portion vertically below the bearing portion and configured to guide the cooling oil guided by the inner wall portion to an inner periphery vertically below the coil end portion; a cooling section including a refrigerant pipe that is arranged in a serpentine manner so as to extend horizontally within a plane along the inner wall section and is thermally connected to the inner wall section, and that cools the cooling oil that is guided to the inner wall section; A cooling structure for a rotating electric machine having the above structure.

2. The cooling portion is disposed in a region of the inner wall portion vertically above the bearing portion. The cooling structure for a rotating electrical machine according to claim 1 .

Images