JP2009284718A - Cooler and cooling method for coil end of rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the cooling properties of a coil end projecting from a stator core of a rotary electric machine. <P>SOLUTION: A coolant injected from a coolant groove 16 of an end plate 8 fixed in a rotor core of the rotary electric machine (motor-generator) to a vicinity of the outer side of the end face of the stator core 9, is received by a guide portion of a coolant guide member 17 fixed in the end face of the stator core 9, and guided to a part facing the end face of the stator core 9 of the coil end 11, to cool efficiently the interior likely to have a high temperature in the coil end 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for cooling a coil end protruding from a stator core of a stator coil in a rotating electrical machine.

  In a rotating electrical machine, when the temperature of the stator (stator coil and stator core) rises due to heat generated by energization of the stator coil, the performance decreases, and cooling is necessary.

Patent Document 1 discloses a structure in which a coolant scattered from a coolant discharge port provided on a rotating shaft (rotor shaft) of a rotor is supplied to a coil end of a stator to be cooled.
JP-A-2005-73351

  In the conventional coil end cooling structure disclosed in Patent Literature 1 and the like, the refrigerant passes through the gap between the stator core end face and the coil end, and thus the coil end cannot be sufficiently cooled.

  Also, in order to prevent the coil end from rising above the limit temperature, the temperature of the coil end is detected, and when the detected temperature exceeds the threshold value, the energization amount to the stator coil is reduced. Therefore, it is difficult to attach the temperature sensor to the inside of the coil end where the temperature is highest, and as a result, an excessive temperature rise at the coil end cannot be sufficiently prevented.

  The present invention has been made paying attention to such a conventional problem, and an object of the present invention is to increase the cooling effect of the coil end and thus the stator by efficiently supplying a refrigerant to the coil end of the stator.

  Another object of the present invention is to perform fail-safe control based on a temperature detection value by changing the temperature distribution of the coil end, thereby sufficiently preventing an excessive temperature rise of the coil end.

In order to achieve the first object, the present invention provides:
The refrigerant passage in the rotor end plate is ejected toward the outside of the stator core end surface,
A refrigerant guide member is disposed at an end portion of the stator core, and the coolant ejected from the refrigerant passage is received by the guide portion facing the gap between the coil end of the guide member and the stator core end surface, and the stator core at the coil end is received. It was set as the structure guided to the part facing an end surface.

In order to achieve the second object, in addition to the above configuration,
A temperature sensor is provided at a position sandwiched by a plurality of coil ends on the outer peripheral surface around the rotor rotation axis of the coil end to detect the temperature of the coil end.
When the coil end temperature exceeds the threshold value, the energization amount to the stator coil is reduced.

  The refrigerant ejected from the refrigerant passage in the end plate toward the outside of the stator core end surface is received by the guide portion of the guide member, guided to the guide portion, and guided to the portion of the coil end facing the stator core end surface.

  Thereby, since a refrigerant | coolant is intensively supplied to the part facing the stator core end surface of a coil end, the inside of a coil end can be cooled efficiently and the cooling effect of a coil end and a stator can be heightened.

  As a result, the outer peripheral side around the rotor rotation axis of the coil end away from the portion where the refrigerant is applied becomes the highest temperature. Therefore, by providing the temperature sensor at a position sandwiched between two adjacent coil ends on the outer peripheral surface of the coil end, the temperature can be detected at a position where the coil end is at the highest temperature.

  Thus, fail-safe control for preventing an excessive temperature rise based on the detected temperature value can be appropriately performed while accurately detecting the maximum temperature of the coil end.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of a rotating electrical machine provided with a coil end cooling device according to an embodiment of the present invention.

  The rotating electrical machine according to the present embodiment is a motor generator that serves as both an electric motor and a generator in a hybrid vehicle, and includes a rotor 1 and a stator 2 and is housed in a case 3 of a T / A (transaxle).

  The rotor 1 is formed by laminating an electromagnetic steel plate and a rotor shaft 5 which is rotatably supported relative to the pump shaft 4 on the outer periphery of a pump shaft 4 of an oil pump rotating in conjunction with a crankshaft of an engine (internal combustion engine) (not shown). The rotor core 6 formed and fixed to the outer periphery of the rotor shaft 5, the plurality of permanent magnets 7 embedded in the vicinity of the outer peripheral surface of the rotor core 6, and the end of the nonmagnetic material fixed with the both ends of the rotor core 6 sandwiched therebetween It consists of a plate 8.

  The stator 2 disposed in the vicinity of the outer periphery of the rotor 1 is fixed to the case 3 and has a stator core 9 formed by laminating electromagnetic steel sheets, and 3 stored in a plurality of slots formed in the stator core 9. A portion of the stator coil 10 that protrudes outward from the stator core 9 of the stator coil 10 forms a coil end 11.

  Accordingly, the rotor 1 is rotated by a magnetic field generated by a current supplied to the stator coil 10 and the rotor shaft 5 is used as an output shaft, thereby operating as an electric motor. Also, the rotor shaft 5 is used as an input shaft and the rotor 1 is rotated. By generating a current in the stator coil 10, it operates as a generator.

  When the rotating electric machine (motor generator) having such a configuration is operated as an electric motor or a generator, the stator 2 generates heat together with the rotor 1, so that the refrigerant is supplied to the coil end 11 to be cooled.

  The cooling device for the coil end 11 will be described.

  In the central shaft portion of the pump shaft 4, there are formed a refrigerant introduction path 12 for introducing a refrigerant (lubricating oil: ATF) and a branch path 13 branched radially from the refrigerant introduction path 12 to reach the outer peripheral surface of the pump shaft 4. The

  A gap is provided between the outer peripheral surface of the pump shaft 4 and the inner peripheral surface of the rotor shaft 5, and this gap is formed as a distribution passage 14 that distributes the refrigerant flowing out of the branch passage 13 to both sides in the axial direction.

  In the rotor shaft 5, a plurality of (for example, four) refrigerant holes 15 are formed at equal intervals in the circumferential direction through the inner peripheral surface portion facing the distribution passage 14 and the outer peripheral surface.

  Each end plate 8 is formed with a plurality of (for example, four) refrigerant grooves 16 that overlap with the plurality of refrigerant holes 15.

  On the other hand, a coolant guide member 17 that receives the coolant ejected from the coolant groove 16 and guides it to the center of the portion of the coil end 11 that faces the end surface of the stator core 9 is fixed to the end surface of the stator core 9.

  The refrigerant guide member 17 is formed as follows.

  FIG. 2 shows a state before processing of the coolant guide member 17, which is formed by punching a sheet metal with a press, and is arranged on the outer ring side 171 and the inner ring side of the ring part 171 in the center direction of the ring. And a plurality of strip portions 172 extending toward the top.

  The strips 172 are provided in the same number as the number of slots (= number of teeth between slots) in which the stator coils are accommodated.

  Each strip portion 172 is bent on the same side along the illustrated broken line a in the radial intermediate portion of the ring, and the outer peripheral side portion 172A connected to the ring portion 171 is connected to the stator core 9 together with the ring portion 171 as described later. The mounting part is configured.

  On the other hand, the inner peripheral portion 172B from the broken line a is bent by a pair of bent lines b connecting both ends of the bent line a and the center of the inner peripheral end of the inner peripheral portion 172B.

  FIG. 3 shows details of a state in which the refrigerant guide member 17 is attached to the stator core 9.

  An attachment portion composed of the annular portion 171 and the outer peripheral side portion 172A is joined to the end surface of the stator core 9 and fixed to the end surface of the stator core 9 by spot welding (s) in a plurality of places.

  The inner peripheral side portion 172B is bent at a fold line a so as to face the gap between the coil end 11 and the end face of the stator core 9. Furthermore, the two side guide portions 172b2 on both sides of the central guide portion 172b1 move away from the end surface of the stator core 9 with respect to the central guide portion 172b1 having an isosceles triangle shape having three sides of the broken line a and a pair of bent lines b. Folded along the fold line b.

  The central guide portion 172b1 of the inner peripheral side portion 172B is inclined away from the end surface of the stator core 9 toward the outer peripheral side from the inner peripheral end (the base of the isosceles triangle) and approaches the coil end 11, and both guide portions 172b2 are From the center guide part 172b1, it arrange | positions inclining in the direction which approaches the coil end 11 further. The inner peripheral side portion 172B having the central guide portion 172b1 and the both side guide portions 172b2 bent as described above serves as a guide portion that guides the refrigerant to the center portion of the coil end 11 facing the end surface of the stator core 9 as will be described later. Constitute.

  The refrigerant guide member 17 having the above configuration is first attached to the stator core 9 according to its shape, and then the stator coil 10 is wound around the stator core 9.

  The operation of the coil end cooling device configured as described above will be described with reference to FIG.

An oil pump (not shown) is connected to the end of the pump shaft 4, and the refrigerant discharged from the oil pump is introduced into the refrigerant introduction path 12 of the pump shaft 4, and then from the branch path 13 to the distribution path 14. The refrigerant that has flowed out and is distributed in the horizontal direction in the drawing in the distribution passage 14 is jetted from the refrigerant groove 16 at a high pressure through the refrigerant hole 15 by adding centrifugal force to the pump discharge pressure.

  Refrigerant jetted from the coolant groove 16 of the stator core 9 between the end surface of the stator core 9 and the coil end 11 is received by the guide portion of the coolant guide member 17 and is a portion of the coil end 11 facing the end surface of the stator core 9. Guided to the center.

  Specifically, when the refrigerant ejected from the refrigerant groove 16 hits the central guide part 172b1 and the both side guide parts 172b2, the end face of the stator core 9 of the coil end 11 is bounced back or along the inclined surfaces of these guide parts. In particular, the refrigerant that scatters from each direction overlaps at the center of this part, and the most refrigerant is sprayed.

  As a result, as shown in FIG. 5A, the portion of the coil end 11 where the refrigerant is sprayed most, that is, the intermediate layer between the outer peripheral side and the inner peripheral side is cooled most efficiently, It becomes a low temperature region. Next, since a considerable amount of the refrigerant is sprayed also on the inner peripheral side portion, it becomes an intermediate / low temperature region, and the outer peripheral portion where the refrigerant hardly hits becomes an intermediate temperature region where the temperature is relatively high.

  When the refrigerant guide member is not provided, as shown in FIG. 5B, the refrigerant that is ejected toward the gap between the coil end 11 and the end face of the stator core 9 passes through the gap and enters the coil end 11. Since it hardly hits, the central part of the cross section of the coil end 11 becomes the hottest region due to heat accumulation.

  In addition, the protruding portion near the slot of the coil end 11 is cooled by being directly sprayed with the refrigerant ejected from the refrigerant groove 16.

  Thus, by providing the coolant guide member 17, a sufficient amount of coolant is sprayed onto the portion of the coil end 11 facing the end surface of the stator core 9 where the coolant has conventionally been difficult to be supplied, thereby cooling the coil. The end 11 can be efficiently cooled, and as a result, the entire stator can be sufficiently cooled, and the performance of the rotating electrical machine can be maintained well.

  Moreover, although not shown in figure, it is good also as a structure which forms an annular part as an attaching part which fixes to the stator coil inner peripheral side of a stator core, and provides the strip part which extends radially from an annular part and forms a guide part.

  FIG. 6 shows another form of the refrigerant guide member.

  FIG. 4A shows a state before bending, and forming a sheet metal made of a nonmagnetic metal by stamping is the same as in the first embodiment, but a strip 171 ′ extending linearly, The strip portion 171 ′ is formed to have a plurality of strip portions 172 ′ extending like comb teeth in a direction perpendicular to the longitudinal direction of the strip portion 171 ′.

  The belt portion 171 ′ is rounded into a cylindrical shape, the strip portion 172 ′ is positioned on the coil end 11 side and joined to the outer peripheral surface of the stator core 9, and both ends are overlapped and joined by spot welding.

  The strip portion 172 ′ is joined to the boundary edge portion between the outer peripheral surface and the end surface of the stator core 9 at the boundary with the strip portion 171 ′ and bent toward the end surface side of the stator core 9, and is outer peripheral from the bent line a in the intermediate portion. Are joined to the end face of the stator core 9 and fixed at a plurality of locations by spot welding.

  It is the first embodiment that the inner peripheral side of the broken line a is bent along the broken line b to form a guide portion composed of a central guide portion 172b1 ′ and both side guide portions 172b2 ′ facing the gap between the end face of the stator core 9 and the coil end 11. Although it is the same as the form, since it is formed wide toward the end side, both side guide portions 172b2 ′ can be formed larger, and the receiving area of the refrigerant can be increased.

  In the second embodiment, the number of processing steps (the number of bendings) increases compared to the first embodiment, but even when the number of slots is large, there is a relatively large space between the portions forming the guide portions. Both side guide portions 172b2 'can be easily formed large.

  Also in the second embodiment, the refrigerant guide member can be attached to the stator core prior to the stator coil. However, after winding the stator coil first, the bent guide portion is placed between the end face of the stator core 9 and the coil end. The band portion 171 ′ can be wound around the outer peripheral surface of the stator core 9 and fixed while being inserted into the gap.

  Further, since the annular portion 171 is provided in the first embodiment and the belt portion 171 ′ is provided in the second embodiment, and a plurality of strip portions 172, 172 ′ are integrally formed thereon, the refrigerant guide member 17 ′ is used as the stator core. 9 is easy to install and requires fewer parts. However, the respective strips constituting the guide portion may be separated and formed, and the strips can be fixed after winding the stator coil.

  In addition, since the refrigerant guide member 17 is formed of a nonmagnetic metal, the performance of the rotating electrical machine can be favorably maintained without affecting the magnetic field.

  Note that, as in the third embodiment shown in FIG. 7, the guide portion 172 ″ may be formed to be curved in a U-shaped cross section.

  Also, the refrigerant guide member can be formed of a resin material, and is fixed using an adhesive having refrigerant resistance, or the guide portion 173 and the attachment portion 174 are integrated as shown in FIG. It is good also as a structure which divides | segments into two members with which it was prepared, and the flange part 175 which provided the end part of the semicylindrical attachment part 174 protruded in the outer-diameter direction is fastened with the volt | bolt 176.

  By the way, even if the coil end is cooled by the refrigerant, the coil end may excessively rise in temperature transiently for some reason. Therefore, as described above, a temperature sensor is attached to the coil end, and when the detected coil end temperature exceeds the threshold value, the current flowing to the stator coil is reduced and maintained within the limit temperature. Control is taking place.

  Hereinafter, embodiments in which the fail-safe control is applied to the above-described embodiments will be described.

  According to the embodiment described above, as shown in FIG. 5A, the region where the coil end 11 is the hottest is the outer peripheral portion around the rotor rotation axis where the refrigerant is difficult to be applied, and the most from the stator core 9. Shifted away.

  Therefore, in the present embodiment, as shown in FIG. 9, the temperature sensor 18 that detects the temperature of the coil end 11 is used as an outer periphery around the rotor rotation axis among the plurality of coil ends 11 that form each pole of the stator 2. It is provided at a position sandwiched between two coil ends 11A and 11B adjacent in the vicinity of the surface.

  The mounting position of the temperature sensor 18 is difficult to be applied with the refrigerant, and can be sandwiched between two coil ends to increase the contact area with the coil end, so that the temperature of the highest temperature portion at the coil end is detected. can do.

  Since the upper coil end 11 is more difficult to cool than the lower coil end 11 because the refrigerant scatters against gravity, it is more desirable that the temperature sensor 18 be disposed near the top.

  The output of the temperature sensor 18 is input to an ECU (electronic control unit) 19, and the ECU 19 performs fail-safe control for preventing an excessive temperature rise of the coil end 11 based on the input detection value of the coil end 11. Do.

  FIG. 10 shows a general flow of the fail-safe control. The temperature of the coil end detected by the temperature sensor 18 is read and compared with a threshold value set lower than the limit temperature (S1, S2). When it is determined that the threshold value has been exceeded, the current flowing to the stator coil is corrected to decrease (S3), thereby reducing the amount of heat generated from the stator coil, thereby preventing an excessive temperature rise at the coil end. it can.

  In the present embodiment, since the maximum temperature of the coil end can be detected with high accuracy, fail-safe control can be optimally performed without causing a delay in control or conversely unnecessary control.

Sectional drawing which shows schematic structure of the rotary electric machine provided with the coil end cooling device which concerns on one Embodiment of this invention. The figure which shows the state before a process of the refrigerant | coolant guide member of embodiment same as the above. The figure which shows the detail of the state which attached the guide member same as the above to the stator core The figure which shows the effect | action of embodiment same as the above The figure which shows the temperature distribution of the coil end in embodiment same as the above compared with the case where a refrigerant guide member is not provided. The figure which shows 2nd Embodiment provided with another refrigerant | coolant guide member. The figure which shows 3rd Embodiment from which the shape of the guide part of a refrigerant | coolant guide member differs. The figure which shows 4th Embodiment provided with another refrigerant guide member. The figure which shows 5th Embodiment which applied the fail safe control based on a coil temperature detection value. Flowchart showing the general flow of failsafe control

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotor 2 Stator 6 Rotor core 8 End plate 9 Stator core 10 Stator coil 11 Coil end 12 Refrigerant introduction path 13 Branch path 14 Distribution path 15 Refrigerant hole 16 Refrigerant groove 17, 17 'Refrigerant guide member 18 Temperature sensor 19 ECU (electronic control unit)
171 Circular portion 171 ′ Band portions 172, 172 ′ Strip portions 172b1, 172b1 ′ Central guide portions 172b2, 172b2 ′ Both side guide portions 173 Guide portions 174 Mounting portions 175 Flange portions 176 Bolts

Claims (13)

A coil end cooling device for a rotating electrical machine comprising: a rotor having an end plate fixed to an end portion of a rotor core; and a stator having a coil end protruding from the end portion of the stator core,
A refrigerant passage formed in the end plate and ejecting the refrigerant toward the outside of the stator core end surface;
A guide portion disposed at an end portion of the stator core and facing a gap between the coil end and the end surface of the stator core, the guide portion receiving the refrigerant ejected from the refrigerant passage and the stator core end surface of the coil end; A refrigerant guide member formed in a shape leading to the facing portion;
The coil end cooling device of the rotary electric machine comprised including.   The coil of the rotating electrical machine according to claim 1, wherein the guide member includes an attachment portion fixed to an end portion of the stator core, and a plurality of guide portions that are continuous with the attachment portion and face the plurality of gaps. End cooling device.   The coil end cooling device for a rotating electrical machine according to claim 2, wherein the mounting portion is formed in a flat annular shape and is fixed to an outer peripheral edge portion or an inner peripheral edge portion of an end surface of the stator core.   The coil end cooling device for a rotating electrical machine according to claim 2, wherein the attachment portion includes a portion formed in a cylindrical shape and fastened to an outer peripheral surface of an end portion of the stator core.   The guide portion is a central guide portion that is inclined in a direction approaching a portion facing the stator core end surface of the coil end from the inner peripheral side close to the stator core end surface toward the outer peripheral side in the central portion of the gap facing the guide portion. And a both-side guide portion formed to bend to the side away from the end face of the stator core from the center guide portion, being connected to both sides of the center guide portion in the rotor rotation direction. The coil end cooling device for a rotating electrical machine according to any one of the above.   The coil end cooling device for a rotating electrical machine according to claim 5, wherein the central guide portion is formed in a triangular shape having a base on the inner peripheral end side of the stator core end surface and having a vertex on the outer peripheral side.   The coil end cooling device for a rotating electrical machine according to any one of claims 1 to 6, wherein the guide member is formed of a nonmagnetic material.   The coil end cooling device for a rotating electric machine according to claim 7, wherein the guide member is formed by bending a nonmagnetic metal plate.   The temperature sensor for detecting the temperature of the coil end is provided on the outer peripheral side of the coil end around the rotor rotation axis and in the vicinity of the end in the direction away from the end surface of the stator core. A coil end cooling device for a rotating electric machine according to claim 1.   The coil end cooling device for a rotating electrical machine according to claim 9, wherein the temperature sensor is provided at a position sandwiched between two adjacent coil ends on an outer peripheral surface of the coil end around the rotor rotation axis. The coil of the rotating electrical machine according to claim 9 or 10, comprising control means for reducing an energization amount to the stator coil when a coil end temperature detected by the temperature sensor exceeds a threshold value. End cooling device. A coil end cooling method for a rotating electrical machine comprising: a rotor having an end plate fixed to an end portion of a rotor core; and a stator in which a coil end protrudes from the end portion of the stator core,
Receiving refrigerant jetted from the refrigerant passage in the end plate toward the outside near the end face of the stator core,
A method for cooling a coil end of a rotating electric machine, wherein the refrigerant is guided to a central portion of a portion of the coil end facing the end face of the stator core. The coil end cooling method for a rotating electrical machine according to claim 12, wherein when the detected coil end temperature exceeds a threshold value, the energization amount to the stator coil is reduced.

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