JP2010279226A - Cooling structure of coil, stator and rotary electric machine, as well as vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling structure of a coil, capable of cooling the coil efficiently, and to provide a stator, a rotary electric machine and a vehicle which are equipped with the cooling structure of a coil. <P>SOLUTION: The cooling structure of a coil includes a coil 222 consisting of a winding which has a flat cross-section and multiple turns wound around each tooth of a stator core 221. The coil 222 includes a long diameter part 222A, and a short diameter part 222B contiguous to the long diameter part 222A. Cooling medium for cooling the coil 222 is supplied to the long diameter part 222A and the short diameter part 222B. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coil cooling structure, a stator and a rotating electric machine, and a vehicle, and more particularly, to a coil cooling structure including a winding having a flat cross section, and a stator, a rotating electric machine, and a vehicle including the winding structure.

  Japanese Patent Laying-Open No. 2006-311750 (Patent Document 1) discloses a cooling device for a rotating electrical machine in which an oil passage groove is formed along at least one of an outer periphery and an inner periphery of a coil end during shaping of the coil end. Yes.

  Japanese Patent Laying-Open No. 2005-304244 (Patent Document 2) discloses that, in a coil of a rotating electrical machine, an inner portion of a bending portion is shifted by an adjacent winding. In this document, since the bulges inside the bent portion do not face each other, the thickness of the entire coil can be suppressed.

JP 2006-31750 A JP-A-2005-304244

  An edgewise coil composed of a winding with a flat cross section has the advantage of a high space factor. However, since the heat generation density increases due to the high space factor, it is highly important to perform efficient cooling.

  Patent Document 1 discloses a coil cooling device. In this device, a groove is formed on the outer periphery of the coil end, thereby reducing the coil cross-sectional area and increasing the current density. There is a problem of increasing.

  The structure of the coil described in Patent Document 2 is intended to provide a compact and highly reliable edgewise coil, and is completely premised on the present invention aimed at efficiently cooling the coil. Different.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a coil cooling structure capable of efficiently cooling a coil, a stator including the same, a rotating electrical machine, and To provide a vehicle.

  The coil cooling structure according to the present invention includes a tooth portion and a coil having a flat cross section and is wound a plurality of times around the tooth portion. The coil includes a long diameter portion and a short diameter adjacent to the long diameter portion. A cooling medium for cooling the coil is supplied to the long diameter portion and the short diameter portion.

  According to the above configuration, the contact area between the coil and the cooling medium is increased by providing the coil with the long diameter portion and the short diameter portion adjacent to the long diameter portion and supplying the cooling medium to cool the coil to them. The cooling efficiency of the coil can be improved.

  In the present specification, the “major axis portion” means a turn having a portion having a relatively large distance from the coil center among a plurality of turns constituting the coil, The “part” means a turn having a part having a relatively small distance from the center of the coil among a plurality of turns constituting the coil.

  In one embodiment, in the cooling structure for the coil, the long diameter portion and the short diameter portion are repeated a plurality of times in the longitudinal direction of the tooth portion.

  In one embodiment, in the coil cooling structure, each of the long diameter portion and the short diameter portion is composed of one turn of winding.

  In one embodiment, in the coil cooling structure, a plurality of teeth portions are formed side by side on the same circumference, and the long diameter portion and the short diameter portion are respectively located on the same circumference on the plurality of teeth portions. Formed as follows.

  In one embodiment, in the coil cooling structure, a plurality of teeth portions are formed side by side on the same circumference, and the long diameter portion and the short diameter portion are respectively arranged in a staggered manner on the plurality of tooth portions.

  In one embodiment, in the coil cooling structure, a step difference structure having a long diameter portion and a short diameter portion is formed on both sides of the tooth portion.

  In the coil cooling structure, as one example, one coil is wound around one tooth portion, and as another example, one coil is wound around a plurality of tooth portions.

The stator according to the present invention includes the above-described coil cooling structure.
The rotating electrical machine according to the present invention includes the stator described above.

  A vehicle according to the present invention includes a drive unit including the rotating electrical machine described above.

  According to the present invention, the coil can be efficiently cooled.

1 is a schematic diagram showing a configuration of a hybrid vehicle to which a vehicle drive unit including a coil cooling structure according to an embodiment of the present invention is applied. It is the schematic which shows the structure of the drive unit of the vehicle containing the cooling structure of the coil which concerns on one embodiment of this invention. It is sectional drawing which shows the structure of the coil wound by the teeth part of a stator core. 1 is a cross-sectional perspective view of a stator including a coil cooling structure according to an embodiment of the present invention. It is a figure for demonstrating the cooling effect of the cooling structure of the coil which concerns on one embodiment of this invention. It is VI-VI sectional drawing in FIG. It is sectional drawing which concerns on the comparative example with respect to FIG. It is a figure for demonstrating the modification of the cooling structure of the coil which concerns on one embodiment of this invention. It is a top view which shows an example of the cooling structure of the coil which concerns on one embodiment of this invention. It is a top view which shows the other example of the cooling structure of the coil which concerns on one embodiment of this invention. It is a figure which shows the relationship of (alpha) (heat transfer coefficient) xA (surface area) magnification of a refrigerant | coolant, and coil maximum temperature / refrigerant | coolant flow rate.

  Embodiments of the present invention will be described below. Note that the same or corresponding portions are denoted by the same reference numerals, and the description thereof may not be repeated.

  Note that in the embodiments described below, when referring to the number, amount, and the like, the scope of the present invention is not necessarily limited to the number, amount, and the like unless otherwise specified. In the following embodiments, each component is not necessarily essential for the present invention unless otherwise specified.

  FIG. 1 is a schematic diagram showing a configuration of a hybrid vehicle to which a vehicle drive unit including a coil cooling structure according to an embodiment of the present invention is applied. Referring to FIG. 1, the hybrid vehicle according to the present embodiment includes an engine 1, a drive unit 2, a PCU 3, and a battery 4. The drive unit 2 is electrically connected to the PCU 3 via the cable 3A. The PCU 3 is electrically connected to the battery 4 via the cable 4A.

  The engine 1 that is an internal combustion engine may be a gasoline engine or a diesel engine. The drive unit 2 generates a driving force for driving the vehicle together with the engine 1. Both the engine 1 and the drive unit 2 are provided in the engine room of the hybrid vehicle. The PCU 3 is a control device that controls the operation of the drive unit 2.

  FIG. 2 is a schematic diagram for explaining the internal structure of the drive unit 2. Referring to FIG. 2, drive unit 2 includes motor generators 100 and 200, power split mechanism 300, counter gear 400, and differential gear 500.

  Motor generators 100 and 200 are rotating electrical machines having at least one function of an electric motor and a generator. Power split device 300 is provided between motor generators 100 and 200. Counter gear 400 is provided between power split device 300 and differential gear 500. Differential gear 500 is connected to the drive shaft via a drive shaft receiving portion. Motor generators 100 and 200, power split device 300, counter gear 400 and differential gear 500 are housed in a casing.

  Motor generators 100 and 200 are electrically connected to cable 3A. The other end of the cable 3A is connected to the PCU 3 as shown in FIG. Thereby, battery 4 and motor generators 100 and 200 are electrically connected via PCU 3 and cables 3A and 4A.

  Motor generators 100 and 200 include rotors 110 and 210 and stators 120 and 220, respectively. Stator 120 and 220 include stator cores 121 and 221 and stator coils 122 and 222 wound around stator cores 121 and 221.

  Power split device 300 is configured to include planetary gears 310 and 320. Planetary gears 310 and 320 include sun gears 311 and 321, pinion gears 312 and 322, planetary carriers 313 and 323, and ring gears 314 and 324, respectively.

  The crankshaft 1A of the engine 1, the rotor 110 of the motor generator 100, and the rotor 210 of the motor generator 200 rotate about the same axis.

The sun gear 311 in the planetary gear 310 is coupled to a hollow sun gear shaft that penetrates the center of the crankshaft 1A. The ring gear 314 is rotatably supported coaxially with the crankshaft 1A. The pinion gear 312 is disposed between the sun gear 311 and the ring gear 314 and revolves while rotating on the outer periphery of the sun gear 311. Planetary carrier 313 is coupled to the end of crankshaft 1 </ b> A and supports the rotation shaft of each pinion gear 312.

  The rotor 220 of the motor generator 200 is coupled to a ring gear case that rotates integrally with the ring gear 314 of the planetary gear 310 via a planetary gear 320 as a speed reducer.

  The planetary gear 320 performs speed reduction by a structure in which a planetary carrier 323 that is one of rotating elements is fixed to a case of a vehicle drive device. That is, planetary gear 320 meshes with sun gear 321 coupled to the shaft of rotor 210, ring gear 324 that rotates integrally with ring gear 314, ring gear 324 and sun gear 321, and pinion gear 322 that transmits the rotation of sun gear 321 to ring gear 324. Including.

  When the vehicle travels, the power output from the engine 1 is transmitted to the crankshaft 1A and divided into two paths by the power split mechanism 300.

  One of the two paths is a path that is transmitted from the counter gear 400 to the drive shaft via the differential gear 500. The driving force transmitted to the drive shaft is transmitted as a rotational force to the drive wheels, and causes the vehicle to travel.

  The other is a path for driving the motor generator 100 to generate power. Motor generator 100 generates power using the power of engine 1 distributed by power split device 300. The electric power generated by the motor generator 100 is properly used according to the traveling state of the vehicle and the state of the battery 4. For example, during normal traveling and sudden acceleration of the vehicle, the electric power generated by motor generator 100 becomes the electric power for driving motor generator 200 as it is. On the other hand, under the conditions determined in battery 4, the electric power generated by motor generator 100 is stored in battery 4 through an inverter and a converter provided in PCU 3.

  Motor generator 200 is driven by at least one of the electric power stored in battery 4 and the electric power generated by motor generator 100. The driving force of the motor generator 200 is transmitted from the counter gear 400 to the drive shaft via the differential gear 500. By doing so, the driving force of the engine 1 can be assisted by the driving force from the motor generator 200, or the vehicle can be driven only by the driving force from the motor generator 200.

  On the other hand, during regenerative braking of the vehicle, the driving wheels are rotated by the inertial force of the vehicle body. Motor generator 200 is driven through the drive shaft, differential gear 500 and counter gear 400 by the rotational force from the drive wheels. At this time, the motor generator 200 operates as a generator. Thus, motor generator 200 acts as a regenerative brake that converts braking energy into electric power. The electric power generated by the motor generator 200 is stored in the battery 4 via an inverter provided in the PCU 3.

  Next, the structure of the stator coil 222 wound around the stator core 221 will be described with reference to FIG. As shown in FIG. 3, the stator core 221 is provided with a tooth portion 221A that protrudes radially inward, and the stator coil 222 is wound around the tooth portion 221A. Stator coil 222 according to the present embodiment is an edgewise coil made of a winding having a substantially rectangular shape with a flat cross section.

  An edgewise coil composed of a winding with a flat cross section has the advantage of a high space factor. However, since the heat generation density increases due to the high space factor, it is highly important to perform efficient cooling.

  FIG. 4 is a cross-sectional perspective view of the stator 220. Referring to FIG. 4, stator 220 includes a coil end cover 223, an inner diameter side cover 224, and a ring 225 in addition to stator core 221 and stator coil 222.

  The coil end cover 223 is formed so as to cover the coil end of the stator coil 222. The coil end means a portion of the stator coil 222 located on the end surface in the axial direction of the stator core 221.

  The inner diameter side cover 224 is provided on the inner peripheral surface of the stator core 221, that is, on the tip of the tooth portion 221 </ b> A. Ring 225 is provided on the outer peripheral surface of stator core 221. The ring 225 functions as a fastening ring that fastens a stator core 221 that is formed by being divided into a plurality of pieces in the circumferential direction.

  As described above, the coil end of the stator coil 222 is covered with the coil end cover 223. Therefore, the cooling of the stator coil 222 can be promoted by flowing the coolant through the coil end cover 223 (in the direction of the arrow DR223). As the refrigerant, oil circulating in the casing constituting the drive unit 2 is supplied. The efficiency of cooling by the refrigerant is determined by the heat transfer coefficient, flow rate, contact area between the refrigerant and the coil, and the like.

  Next, the cooling effect of the coil cooling structure according to the present embodiment will be described with reference to FIGS. FIG. 5 is a view showing the stator core 221 according to the present embodiment as viewed from the inside in the radial direction, and FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 7 is a cross-sectional view according to a comparative example with respect to FIG.

  With reference to FIGS. 5 and 6, in stator 220 according to the present embodiment, long diameter portion 222 </ b> A and short diameter portion 222 </ b> B are repeated for each turn of stator coil 222. On the other hand, as shown in FIG. 7, in the stator 2200 according to the comparative example, the diameter of the stator coil 2220 wound around the teeth portion of the stator core 2210 is substantially constant throughout.

  As shown in FIGS. 5 and 6, by providing the stator coil 222 with the long diameter portion 222A and the short diameter portion 222B alternately, the stator coil 222 flows in the direction of the arrow DR223 relative to the comparative example of FIG. Since the contact area with the refrigerant increases and the heat of the stator coil 222 is easily absorbed by the refrigerant (broken line arrow in FIG. 5), the cooling efficiency is improved.

  As is clear from the description of FIG. 5, the long diameter portion 222A is obtained by extending the length of the stator core 221 in the axial direction (vertical direction in FIG. 5) with respect to the short diameter portion 222B. The long diameter portion 222A and the short diameter portion 222B have the same width along the circumferential direction (left and right direction in FIG. 5).

  5 and 6, the long diameter portion 222A and the short diameter portion 222B are each composed of a single turn winding, but the long diameter portion 222A and the short diameter portion 222B are each composed of a plurality of turns. May be.

  5 and 6, the long diameter portion 222A and the short diameter portion 222B are repeated a plurality of times in the longitudinal direction of the teeth portion 221A (left and right direction in FIG. 6). 222B does not necessarily need to be repeated a plurality of times in the longitudinal direction of the tooth portion 221A, and may be formed one by one.

  In the example of FIGS. 5 and 6, the step difference structure by the long diameter portion 222A and the short diameter portion 222B is formed on both axial sides (upper and lower sides in FIG. 6) sandwiching the teeth portion 221A. The long diameter portion 222A and the short diameter portion 222B may be formed so that the difference structure is formed on one side in the axial direction of the tooth portion 221A.

  Further, in the example of FIGS. 5 and 6, as shown in FIG. 8A, the long diameter portion 222A and the short diameter portion 222B are formed so as not to overlap in the coil end portion. ), The long diameter portion 222A and the short diameter portion 222B may be partially overlapped.

  The long diameter portion 222 </ b> A and the short diameter portion 222 </ b> B described above are respectively formed in the plurality of stator coils 222 in the stator 220. The long diameter portion 222A and the short diameter portion 222B may be formed so as to be positioned on the same circumference on the plurality of teeth portions as shown in FIG. 9, or as shown in FIG. They may be arranged in a staggered manner on the part.

  As shown in FIG. 10, when the long diameter portion 222A and the short diameter portion 222B are arranged in a staggered pattern, the heat exchange efficiency is improved by promoting disturbance of the refrigerant flow as compared with the example of FIG. In addition, the stator coil 222 can be cooled more efficiently.

  FIG. 11 is a diagram showing the relationship between “α (heat transfer coefficient) × A (surface area) magnification”, “maximum coil temperature (° C.)”, and “refrigerant flow rate (L / min)”.

  The values on the horizontal axis in FIG. 11 indicate how many times the product of the heat transfer coefficient (α) of the refrigerant and the contact area (A) between the refrigerant and the coil is compared to the comparative example shown in FIG. Is. When this magnification is high, the flow rate of the refrigerant contributing to cooling of the stator coil 222 is large, and the maximum temperature of the stator coil 222 is low. In the cooling structure of stator coil 222 according to the present embodiment, for example, as shown in FIG. 6, the contact area (A) between the refrigerant and the coil is reduced by forming a long diameter portion 222A and a short diameter portion 222B in each coil. Further, in a preferred example, as shown in FIG. 10, the heat transfer coefficient (α) of the refrigerant can be increased by forming the long diameter portion 222A and the short diameter portion 222B in a staggered manner. As a result, in the stator coil 222 cooling structure according to the present embodiment, the stator coil 222 can be efficiently cooled.

  The above contents are summarized as follows. That is, the coil cooling structure according to the present embodiment includes a tooth portion 221A and a coil 222 that is formed of a winding having a flat cross section and is wound around the tooth portion 221A a plurality of times. The coil 222 includes a long diameter portion 222A and a short diameter portion 222B adjacent to the long diameter portion 222A. A cooling medium for cooling the coil 222 is supplied to the long diameter portion 222A and the short diameter portion 222B.

  Although the concentrated winding structure in which one stator coil 222 is wound around one tooth portion 221A has been mainly described in the present embodiment, the idea of the present invention is that one stator coil 222 has a plurality of tooth portions. The present invention can also be applied to a distributed winding structure wound around 221A.

  Although the embodiments of the present invention have been described above, the embodiments disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 engine, 1A crankshaft, 2 drive shaft, 3 PCU, 3A, 4A cable, 4 battery, 100, 200 motor generator, 110, 210 rotor, 120, 220, 2200 stator, 121, 221, 2210 stator core, 221A teeth part , 122, 222, 2220 Stator coil, 222A long diameter portion, 222B short diameter portion, 223 coil end cover, 224 inner diameter side cover, 225 ring, 300 power split mechanism, 310, 320 planetary gear, 311, 321 sun gear, 312, 322 pinion gear , 313, 323 planetary carrier, 314, 324 ring gear, 400 counter gear, 500 differential gear.

Claims (11)

Teeth section,
Comprising a coil with a flat cross section, comprising a coil wound around the teeth part a plurality of times,
The coil includes a long diameter portion and a short diameter portion adjacent to the long diameter portion,
A coil cooling structure in which a cooling medium for cooling the coil is supplied to the long diameter portion and the short diameter portion.   The coil cooling structure according to claim 1, wherein the long diameter portion and the short diameter portion are repeated a plurality of times in the longitudinal direction of the tooth portion.   The coil cooling structure according to claim 1 or 2, wherein each of the long diameter portion and the short diameter portion is formed of a one-turn winding. The teeth portions are formed side by side on the same circumference,
The coil cooling structure according to any one of claims 1 to 3, wherein the long diameter portion and the short diameter portion are formed on the plurality of teeth portions so as to be positioned on the same circumference. The teeth portions are formed side by side on the same circumference,
4. The coil cooling structure according to claim 1, wherein the long diameter portion and the short diameter portion are respectively arranged in a staggered manner on the plurality of tooth portions. 5.   The coil cooling structure according to any one of claims 1 to 5, wherein a step difference structure including the long diameter portion and the short diameter portion is formed on both sides of the tooth portion.   The coil cooling structure according to claim 1, wherein one coil is wound around one tooth portion.   The coil cooling structure according to claim 1, wherein one coil is wound around a plurality of tooth portions.   A stator including the coil cooling structure according to claim 1.   A rotating electrical machine comprising the stator according to claim 9.   A vehicle comprising a drive unit including the rotating electrical machine according to claim 10.

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