JP2013198311A - Rotating electric machine - Google Patents

Abstract

A rotating electrical machine capable of efficiently cooling without causing an increase in size is provided.
According to a rotating electrical machine according to an embodiment, a coil that is exposed at an axial end of a stator that is accommodated in a casing is brought into contact with the coil to release heat generated in the coil. The cooling oil X flows down from above the heat radiating member 14 to the heat radiating member in a state where the heat radiating member 14 that increases the area of the discharge surface and the housing 11 is formed so as to be open to the space on the space side. A downstream port 27, a piping member 30 that forms a circulation path 25 through which the cooling oil X flowing down from the downstream port 27 is connected from the outlet 29 to the downstream port 27 through which the cooling oil X flows. In addition, a cooling oil circulation unit having a pump 31 that circulates the cooling oil X in the circulation path 25 is provided.
[Selection] Figure 1

Description

  Embodiments described herein relate generally to a rotating electrical machine.

  In recent years, there has been a demand for downsizing and higher output of rotating electrical machines. Now, when the rotating electrical machine is reduced in size, the surface area of the housing is reduced, so that the heat dissipation of the rotating electrical machine is lowered. Further, when the output of the rotating electrical machine is increased, the amount of heat supplied from the coil increases because the power supplied to the coil of the rotating electrical machine increases. At this time, if the heat generated from the coil increases, there is a risk of deteriorating the characteristics of the rotating electrical machine such as a decrease in insulation performance and an increase in so-called copper loss. For this reason, in order to reduce the size and increase the output of the rotating electrical machine, it is important to efficiently cool the coil. At this time, in order to reduce the size of the rotating electrical machine, it is also important to reduce the size of the cooling mechanism for cooling the rotating electrical machine and to reduce the installation space.

JP 2010-154713 A

  The problem to be solved by the present invention is to provide a rotating electrical machine that can be efficiently cooled without causing an increase in size.

  According to the rotating electrical machine of the embodiment, the stator that is housed in the housing and has a coil that generates heat when energized, and the coil that is formed of a heat conductive material and is exposed to the axial end of the stator. A heat-dissipating member that increases the area of the discharge surface that releases heat generated in the coil, and is formed from the upper side of the heat-dissipating member in a state where the housing is formed to be open to the space side in the housing. A downstream port through which cooling oil flows down to the heat radiating member, an outlet through which cooling oil that flows down from the downstream port flows out of the housing, a piping member that connects the outlet port to the downstream port and forms a circulation path through which the cooling oil flows, And a cooling oil circulation unit having a pump for circulating the cooling oil in the circulation path.

The figure which shows typically the cross section of the rotary electric machine of 1st Embodiment. The figure which shows the cross section along the II-II line | wire of FIG. 1 of the rotary electric machine of 1st Embodiment. The figure which shows typically the cross section of the rotary electric machine of 2nd Embodiment.

Hereinafter, a plurality of embodiments of a rotating electrical machine will be described with reference to the drawings. Note that, in a plurality of embodiments described below, substantially the same components are denoted by the same reference numerals, and description thereof is omitted.
(First embodiment)
Hereinafter, the rotating electrical machine according to the first embodiment will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, the rotating electrical machine 10 according to the present embodiment includes a housing 11, a stator 12, a coil 13, a heat pipe 14, and a rotor 15. FIG. 1 schematically shows a state in which the rotating electrical machine 10 is installed. In the following description, the direction along the gravity in the state in which the rotating electrical machine 10 is installed is assumed to be up and down.

  The casing 11 includes a body portion 16 formed in a substantially cylindrical shape having an opening at the front (right side in FIG. 1) and the rear (left side in FIG. 1), and a front flange 17 that closes the opening on the front side of the body portion 16. , And a rear flange 18 that closes the opening on the rear side of the body 16. The details of the casing 11 will be described after the details of the stator 12 and the rotor 15 are described.

  The stator 12 has a stator core 19. The stator core 19 is formed in a cylindrical shape by stacking, for example, core pieces formed by punching magnetic steel plates in an annular shape. The stator core 19 is provided with a plurality of coil insertion grooves (not shown) extending in the stacking direction, that is, in the axial direction, on the inner peripheral side thereof. In the coil insertion groove, for example, a coil 13 corresponding to three phases of U phase, V phase and W phase is inserted. When the coil 13 is inserted into the coil insertion groove, a part of the coil 13 is exposed from both ends of the stator core 19 in the axial direction. As is well known, the coil 13 exposed from the stator core 19 is expanded outward in the circumferential direction of the stator core 19 and then impregnated with varnish or the like and fixed. Thereby, the coil end 20 is formed in the whole area of the circumferential direction in the both ends side of the axial direction of the stator core 19. The stator 12 having such a configuration is fixedly attached to the housing 11 by an attachment jig (not shown).

  Heat pipes 14 are respectively attached to the coil ends 20 formed at both ends of the stator 12. As is well known, the heat pipe 14 is formed of a metal material having good thermal conductivity, that is, a heat conductive material, in a hollow shape (see FIG. 2), and a volatile working fluid is enclosed therein. In the heat pipe 14, evaporation of the working fluid (absorption of latent heat) occurs in the heated portion, and condensation of the working fluid (release of latent heat) occurs in the cooled portion. Specifically, for example, when the lower part of the heat pipe is heated and the upper part is cooled, the hydraulic fluid moves downward due to gravity or the like. As a result, in the heat pipe 14, the movement of heat from the heating side to the cooling side occurs with the movement of the working fluid.

  In the case of this embodiment, the heat pipe 14 is formed of stainless steel. In this case, the heat pipe 14 may be formed of a material other than stainless steel, but it is desirable that the heat pipe 14 be formed of a nonmagnetic material in order to prevent generation of an induced current by the coil 13. As shown in FIG. 2, the heat pipe 14 is formed in an annular shape along the coil end 20 extending in the circumferential direction of the stator 12, and in a discontinuous C shape on the upper side. That is, the heat pipe 14 is in contact with the coil 13 forming the coil end 20 except for a part of the discontinuous portion on the upper side. At this time, the heat pipe 14 is in contact with the coil with an insulating paper (not shown) interposed therebetween. In addition, it is good also as a structure which insulated the surface of the heat pipe 14 with the resin film etc. instead of the insulating paper. The heat pipe 14 corresponds to the heat radiating member described in the claims.

  As shown in FIG. 1, the rotor 15 is provided on the inner peripheral side of the stator 12, and includes a rotor core 21 and a rotating shaft member 22. The rotor core 21 is formed, for example, by stacking core pieces formed by punching magnetic steel plates into a disk shape. The rotor core 21 has a magnet insertion hole (not shown) and a permanent magnet (not shown) inserted into the magnet insertion hole. That is, the rotating electrical machine 10 of the present embodiment is an embedded magnet type electric motor (IPM motor) in which a permanent magnet is embedded in the rotor core 21. The rotary shaft member 22 is press-fitted into a shaft hole 23 provided in the central portion in the radial direction of the rotor core 21 and is fixed to the rotor core 21. The rotary shaft member 22 may be fixed to the rotor core 21 by fitting or insertion instead of press-fitting, or may be formed hollow.

  The rotating shaft member 22 is rotatably supported by bearing members such as a bearing 24 on both end sides with the rotor core 21 interposed therebetween. One end of the rotating shaft member 22, that is, the end on the right side in the drawing, passes through the front flange 17 and protrudes outside the housing 11. The space between the projecting end and the front flange 17 is air-tight and liquid-tight by packing or the like (not shown). A driving object (not shown) is connected to the protruding end of the rotating shaft member 22 via a speed reduction mechanism or the like.

  Here, details of the housing 11 will be described. A cooling oil path 25 through which the cooling oil X flows is formed in the body portion 16 of the housing 11, that is, between the inner peripheral wall portion 16 a and the outer peripheral wall portion 16 b. In this embodiment, as the cooling oil X, mineral oil-based ATF (Automatic Transmission Fluid) used for, for example, a transmission of an automatic vehicle is employed. This cooling oil path 25 is provided on the upper side of the body portion 16 and connects between the inlet 26 opened to the outer peripheral wall portion 16b and the lower outlet 27 opened to the inner peripheral wall portion 16a. As shown in FIG. 1, the downflow port 27 is provided above the heat pipe 14 on both sides of the stator 12 and above the heat pipe 14 in the circumferential direction as shown in FIG. 2.

  The cooling oil X that has flowed down from the flow-down port 27 contacts the heat pipe 14 (including the coil 13, the stator 12, the rotor 15, and the like) and then moves downward due to gravity. The cooling oil X that has moved downward is temporarily stored in an oil storage chamber 28 provided in the housing 11. The oil storage chamber 28 is connected to an outlet 29 provided on the lower side of the housing 11. For this reason, the cooling oil X stored in the oil storage chamber 28 flows out of the casing 11 from the outlet 29. A pipe member 30 that forms a cooling oil path 25 is connected between the outlet 29 and the inlet 26 provided on the upper portion of the trunk portion 16.

  The piping member 30 is provided with a pump 31. The pump 31 transfers the cooling oil X stored in the oil storage chamber 28 toward the inflow port 26. The cooling oil X transferred to the inflow port 26 flows through the cooling oil path 25 and again flows down toward the heat pipe 14 and the like. That is, the cooling oil X circulates between the rotating electrical machine 10 and the piping member 30. The downflow port 27, the outflow port 29, the piping member 30, and the pump 31 constitute a cooling oil circulation unit described in the claims. In FIG. 1, the outlet port 29 is shown below the trunk portion 16 for the sake of simplicity of explanation, but the inlet port 26 may be a position that does not become an obstacle when the rotating electrical machine 10 is installed.

Next, the operation of the rotating electrical machine 10 having the above configuration will be described.
Although not shown, the rotary electric machine 10 is supplied with a drive signal from the drive circuit having an inverter circuit, for example, to the coils 13 of each phase. As a result, a rotational force acts between the stator 12 and the rotor 15 to rotate the rotor 15, that is, the rotary shaft member 22, and the drive target is driven. At this time, the coil 13 provided in the stator 12 generates heat when electric power is supplied. Part of the heat generated from the coil 13 is radiated to the casing 11 of the rotating electrical machine 10 via the stator core 19.

  Now, since the coil 13 exposed from the coil end 20, that is, the stator core 19, has a small area in contact with the stator core 19, it is difficult to dissipate the generated heat to the housing 11. Moreover, since the coil end 20 is hardened and molded with a varnish or the like as described above, its surface area is small. In other words, the coil 13 is formed in a shape in which the generated heat is hardly radiated at the coil end 20.

Therefore, the rotating electrical machine 10 of this embodiment promotes heat dissipation from the coil 13 as follows.
The coil end 20 is provided with a heat pipe 14 as a heat radiating member. As described above, the heat pipe 14 has good thermal conductivity and is in contact with the coil 13. For this reason, the apparent surface area which can be utilized for heat dissipation increases, and the heat dissipation in the coil end 20 is promoted. A downflow port 27 through which the cooling oil X flows down is provided above the heat pipe 14. For this reason, the heat pipe 14 is cooled by directly contacting the cooling oil X flowing down from the flow down port 27. Therefore, heat dissipation from the heat pipe 14, that is, heat dissipation in the coil end 20, is further promoted.

By the way, when the cooling oil X flows down from above, the temperature rises as it moves downward by contacting the heat pipe 14 and taking heat away. For this reason, when the heat radiating member is simply formed of a metal material, although cooling on the upper side where the flowing cooling oil X first contacts is accelerated, the cooling performance is lowered on the lower side. Therefore, in the present embodiment, the heat pipe 14 is employed as the heat radiating member, thereby moving the heat upward in the heat pipe 14. Further, by providing the heat pipe 14 on substantially the entire circumference of the stator 12 as shown in FIG. 2, it is possible to move the heat from almost the entire region of the coil end 20 to the upper side. Thereby, the heat dissipation in the coil end 20 is further promoted.
Then, the cooling oil X deprived of heat flows out of the housing 11 through the outlet 29. That is, the heat in the housing 11 is released to the outside of the housing 11 together with the cooling oil X.
In this way, heat dissipation of the rotating electrical machine 10, that is, cooling of the rotating electrical machine 10 is performed.

  According to the rotating electrical machine 10 according to the present embodiment described above, the heat pipe 14 formed of stainless steel having good thermal conductivity is provided at the coil end 20. This increases the apparent surface area available for heat dissipation at the coil end 20. Further, since the heat pipe 14 is provided in contact with the coil 13, the heat generated from the coil 13 moves to the heat pipe 14 side. Therefore, heat dissipation at the coil end 20 can be promoted. In addition, since the heat pipe 14 is provided in the coil end 20, in other words, since the heat pipe 14 is provided in the casing 11, the outer shape of the rotating electrical machine 10 is not changed, and an increase in size may be caused. Absent.

And the cooling oil X is made to flow down from the upper direction of the heat pipe 14, and the heat pipe 14 is cooled directly. Thereby, the heat radiation in the coil end 20 can be further promoted. Further, since the cooling oil X is circulated to the outside of the housing 11, the heat generated in the housing 11 is discharged to the outside of the housing 11. Therefore, the rotating electrical machine 10 itself can be cooled.
Since the heat pipe 14 is employed as the heat radiating member, heat moves to the upper side inside the heat pipe 14. And the upper side of the heat pipe 14 is in direct contact with the cooling oil X as described above. Therefore, heat dissipation can be further promoted. Further, since the heat pipe 14 is formed in a substantially annular shape extending in the circumferential direction of the stator 12, heat can be transferred from the entire region of the coil end 20.

(Second Embodiment)
A rotating electrical machine according to the second embodiment will be described with reference to FIG. The second embodiment is different from the first embodiment in that the casing is cooled by cooling water. Since the main configuration of the rotating electrical machine is substantially the same as that of the first embodiment, the same reference numerals are given and detailed description is omitted.

  As shown in FIG. 3, the rotating electrical machine 50 of the second embodiment has a cooling water path 51 formed inside the housing 11 in addition to the configuration of the rotating electrical machine 10 of the first embodiment. The cooling water path 51 is formed by a cooling pipe 52 provided in the housing 11 and outside the housing 11. The cooling water path 51 formed in the housing 11 is formed by partitioning the space between the inner peripheral wall part 16 a and the outer peripheral wall part 16 b of the body part 16 from the cooling oil path 25 by the partition wall 53. As shown in FIG. 3, the partition wall 53 extends axially to the cooling oil path 25 on the outer peripheral side of the body portion 16 from the cooling oil path 25 and extends in the circumferential direction although not shown. It is formed along the cooling oil path 25 in the circumferential direction of the body portion 16 on the outer peripheral side (see FIG. 2). That is, the partition wall 53 that partitions the cooling oil passage 25 and the cooling water passage 51 is formed in a shape that extends in the axial direction and the circumferential direction. The cooling oil passage 25 and the cooling water passage 51 are formed in a state where the partition wall 53 is sandwiched therebetween, in other words, in a state where a wide range is close to each other on the upper side of the housing 11.

The cooling water W flowing through the cooling water path 51 is transferred by the pump 54. More specifically, when the pump 54 is driven, the cooling water W flows into the trunk portion 16 from the water supply port 55 provided on the lower side of the trunk portion 16, and moves upward in the trunk portion 16. It flows toward the cooling pipe 52 from the drain port 56 provided on the upper side of the trunk portion 16. Although not shown, the cooling pipe 52 is provided with a cooler or a radiator, and cools the cooling water W flowing through the cooling water passage 51.
In the case of the present embodiment, the cooling oil X is stored in an amount that immerses the lowermost end portion of the heat pipe 14 as a heat radiating member in a space in which the stator 12 in the housing 11 is accommodated. That is, the lower end portion of the heat pipe 14 is always in contact with the cooling oil X.

The rotating electrical machine 50 having such a configuration, like the rotating electrical machine 10 of the first embodiment, has an effect of facilitating heat radiation from the coil end 20 and being efficiently cooled. Then, by directly cooling the housing 11 with the cooling water W, the rotating electrical machine 10 can be cooled more efficiently.
Moreover, since the lowermost end part of the heat pipe 14 is always in contact with the cooling oil X, cooling of the heat pipe 14, in other words, heat radiation from the coil end 20 can be promoted. At this time, the cooling oil X stored on the lower side in the housing 11 is cooled by the cooling water W flowing through the cooling water passage 51 on the lower side of the trunk portion 16. Thereby, cooling from the coil end 20 is further promoted.

  On the other hand, on the upper side of the housing 11, the cooling oil path 25 and the cooling water path 51 are arranged close to each other. As a result, the cooling oil X flowing down from the downflow port 27 is also cooled by the cooling water W flowing through the cooling water passage 51 using the partition wall 53 as a medium. Therefore, the temperature of the cooling oil X that contacts the heat pipe 14 can be lowered, and further cooling can be promoted.

  In this case, the cooling oil path 25 and the cooling water path 51 are partitioned in a state of being close to each other by a partition wall 53 having a large area. For this reason, the cooling oil X flowing through the cooling oil passage 25 on the upper side of the casing 11 is stored in the lower side of the casing 11 (that is, the apparent heat capacity is larger than the upper side). However, the temperature is expected to decrease. Accordingly, the temperature of the upper side of the heat pipe 14 where the cooling oil X flows down is lower than that of the lower side where the cooling oil X is always in contact with the cooling oil X. Therefore, the flow of the working fluid in the heat pipe 14 becomes along the gravity, and the heat can be efficiently transferred.

(Other embodiments)
The cooling oil path 25 is not limited to the path and shape illustrated in FIGS. 1 to 3. For example, a flow-down port 27 may be provided above the stator 12 and the coil 13 to directly cool the coil 13, the stator 12, the rotor 15, the bearing 24, and the like.

  Although the heat pipe 14 is employed as the heat radiating member, a heat radiator such as a so-called heat sink may be employed. If the coil 13 is provided with a heat sink, the surface area of the coil 13, that is, the area for radiating heat increases more than apparent, and more heat can be radiated. In this case, if the case is downsized, a heat sink is provided inside the case, so heat may be trapped in the case, but the heat sink is directly cooled by the cooling oil X and used for cooling. By circulating the cooling oil X (reducing the temperature) and flowing down to the heat sink again, exhaust heat from the inside of the housing can be promoted. Furthermore, it is good also as a structure which combined the heat sink and the heat pipe 14. FIG.

  The shape of the heat pipe 14, that is, the heat radiating member, is not limited to the shape illustrated in FIGS. The coil end 20 is not necessarily formed into a substantially quadrangular shape or a flat (straight) shape on the surface as shown in FIG. Therefore, what is necessary is just to change the shape of a heat radiating member suitably according to the shape of the coil end 20 so that it may become the shape and arrangement | positioning which can contact the coil 13 closely. For example, since the coil end 20 is generally expanded and molded outward in the circumferential direction of the stator core 19, the inner end side of the coil end 20 (however, considering the insertion of the rotor 15, the stator core 19 It is conceivable that it is provided at a position that is radially outward from the inner circumference.

In each embodiment, the heat pipe 14 having a general structure in which the upper side is cooled is used. However, a configuration in which the lower side is cooled by using a capillary structure inside may be adopted.
It is good also as a structure which provides a radiator and a cooler in the cooling oil path | route 25, and cools the circulating cooling oil X.
Although an example in which the cooling water passage 51 is formed inside the trunk portion 16 is shown, the cooling water passage 51 may be provided outside the trunk portion 16. For example, it is conceivable that the piping member 30 forming the cooling water path 51 is wound around the trunk portion 16 to indirectly cool the trunk portion 16, that is, the housing 11.
The rotating electrical machine 10 may be a surface magnet motor (SPM motor) as well as the embedded magnet motor illustrated in each embodiment. Further, instead of the permanent magnet type, an induction motor may be used, and further, not only the motor but also a generator.

  As described above, according to at least one embodiment, the stator having a coil that is housed in the casing and generates heat when energized, and the end of the stator in the axial direction are formed of a heat conductive material. In a state where the housing is provided in contact with the coil exposed to the part and increases the area of the emission surface for releasing the heat generated in the coil, and the housing is opened to the space side. A flow path through which cooling oil flows down from above the heat radiating member, an outlet from which cooling oil flows down from the flow outlet flows out of the housing, and a circulation path through which the cooling oil flows from the outlet to the downstream port And a cooling oil circulation part having a pump for circulating the cooling oil in the circulation path. This increases the apparent surface area that can be used for heat dissipation in the coils exposed on both axial sides of the stator, that is, coil ends. Moreover, since the heat radiation member is provided in contact with the coil, the heat generated from the coil moves to the heat radiation member side. That is, heat dissipation of the coil can be promoted. Further, since the heat radiating member is provided in contact with the coil, that is, in the casing, the outer shape of the rotating electrical machine does not change. Furthermore, since the cooling oil X is caused to flow down from above the heat radiating member and the heat radiating member is directly cooled, it is possible to further radiate heat generated from the coil. Therefore, the coil and thus the rotating electrical machine can be efficiently cooled without causing an increase in size of the rotating electrical machine.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the drawings, 10 and 50 are rotating electrical machines, 11 is a housing, 12 is a stator, 13 is a coil, 14 is a heat pipe (heat radiating member), 16a is an inner peripheral wall portion, 16b is an outer peripheral wall portion, and 25 is a cooling oil path. , 27 is a downstream port, 29 is an outlet, 30 is a piping member, 31 is a pump, 51 is a cooling water path, and 53 is a partition wall.

Claims (5)

A cylindrical housing;
A stator having a coil housed in the housing and generating heat by energization;
A heat dissipating member that is formed of a heat conductive material, is provided in contact with the coil exposed at the axial end of the stator, and increases an area of a discharge surface that releases heat generated in the coil; and
The cooling oil flowing down from the flow-down port, the flow-down port from which the cooling oil flows to the heat-radiating member from above the heat-dissipating member in a state where the case is installed and opened to the space side in the case Has an outflow port that flows out from the housing, a piping member that connects the outflow port to the downflow port to form a circulation path through which the cooling oil flows, and a pump that circulates the cooling oil in the circulation path A cooling oil circulation part;
A rotating electric machine comprising:   The rotating electrical machine according to claim 1, wherein the heat radiating member is formed in an annular shape extending in a circumferential direction of the stator, and is in contact with the coil along the circumferential direction.   The rotating electrical machine according to claim 1, wherein the heat radiating member is a heat pipe.   4. The cooling oil according to claim 1, wherein an amount of at least a lowermost end portion of the heat radiating member is immersed in a space in the casing in which the stator is accommodated. 5. The rotating electric machine according to the item.   The cylindrical casing has a space portion formed between an inner peripheral wall portion and an outer peripheral wall portion thereof, and the cooling oil path that partitions the space portion and flows the cooling oil in the space portion and the casing. 5. The rotating electrical machine according to claim 1, further comprising a partition wall that forms a cooling water path through which cooling water for cooling the air flows.

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