JP2005073351A - Cooling structure of rotating electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cool a stator coil of a motor efficiently using a cooling oil. <P>SOLUTION: The motor is composed of: a stator core 2000 which has a plurality of slots formed and a stator coil attached to the slot; and a rotatable rotor 1010 disposed on the inner peripheral side of a hollow part of the stator core 2000. A cooling structure of the motor comprises an opening part 1202 for jetting the cooling oil from a rotating shaft 1000 of the rotor 1010, and a cooling oil holding member 2500 for holding at a stator coil end 2010 the cooling oil as indicated with an arrow D which has moved under the centrifugal force as shown with arrow C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a structure of a rotary electric machine such as a motor, and more particularly to a cooling structure of a liquid-cooled rotary electric machine mounted on a vehicle such as an automobile.

  A motor or a generator mounted on a vehicle such as an automobile has a rotor (rotor) and a stator core that is disposed around the rotor and is wound with a stator coil. The motor energizes the stator coil to obtain a rotational force, and the generator extracts the current flowing through the stator coil by the rotation of the rotor. When a current flows through the stator coil during rotor rotation, the stator core and the stator coil generate heat. Such heat generation affects the magnetic flux penetrating the inside of the motor or the generator, and decreases the operation efficiency. In order to maintain the operation efficiency, it is necessary to cool the motor and the generator.

  Such a motor or generator is mounted on the vehicle in a form covered with a housing. Therefore, for cooling the motor and the generator, a cooling medium passage is provided in the housing, and cooling with a refrigerant passing through the passage, that is, liquid cooling is often applied. At this time, since it is necessary to ensure insulation of the coil of the electric motor, cooling is performed by a method of flowing cooling water through a refrigerant path provided in a non-contact portion with the coil in the housing or in the vicinity of the heat generating portion. It is performed by a method of flowing or spraying an insulating machine oil or the like. In the method using an insulating refrigerant such as machine oil, it is not necessary to provide a refrigerant path in the housing while maintaining the insulating property. Therefore, the housing can be downsized and the refrigerant is supplied in the vicinity of the heat generating portion. Because it can, it is excellent in terms of large cooling capacity. A technique relating to cooling that includes such a structure and suppresses heat generation of a motor mounted on a vehicle is disclosed in the following publications.

  Japanese Utility Model Laid-Open Publication No. 54-607 (Patent Document 1) discloses a fluid spray cooling device for a rotating device having a spray nozzle. This fluid spray cooling device for a rotating device includes a spray nozzle that is used by being inserted into a hollow rotating shaft that contains a liquid therein and rotates about a rotation center shaft. This spray nozzle consists of a long member that passes through the wall of the hollow rotary shaft and is inserted into the hollow rotary shaft. The elongated member has a central hole extending from the central axis of rotation on a radial line, and at least one fluid in the central axis of rotation is sprayed substantially radially outwardly through the central hole. One aperture is provided near the end. The end of the long member outside the hollow rotary shaft is provided with an opening that radiates fluid in a direction perpendicular to the central axis of rotation, and the end of the long member inside the hollow rotary shaft rotates. The central hole is closed only from the surface not facing the rotation center axis so as to prevent solid particles in the fluid from entering the center hole by centrifugal force acting in the rotation center axis. A number of apertures leading to are provided.

  According to the fluid spray cooling device for a rotating device disclosed in Patent Document 1, a spray nozzle is provided on a hollow rotating shaft. The shape of the spray nozzle is that of a long member and has a central hole. Cooling oil, which is a fluid, is sprayed onto the winding wound around the rotor core from the center hole, and the winding that generates heat by Joule heat is cooled. Since the portion inserted in the hollow shaft of the spray nozzle does not have an opening in the direction in which the centrifugal force acts, the center hole can be prevented from being clogged with solid particles.

  Japanese Patent Laying-Open No. 2003-9467 (Patent Document 2) discloses a motor cooling structure that has a sufficient cooling effect on the terminal portion of a coil. The motor cooling structure includes a rotor provided with magnetized members, a stator provided on the outer periphery side of the rotor and provided with a coil, and a coolant supplied to the center of the rotor provided in the rotor. And a coolant guide section for guiding the terminal section. Particularly preferably, the coolant guide portion is provided on a side surface facing the axial direction of the rotor core.

  According to the motor cooling structure disclosed in Patent Document 2, the coolant is surely guided to the end portion of the coil by the coolant guide portion provided on the rotor, so that the cooling effect on the end portion of the coil is sufficient. be able to. In particular, the coolant flows through the coolant passage in the rotor shaft into the coolant guide portion provided on the side surface of the rotor core and is reliably guided to the end portion of the coil, so that the cooling effect on the end portion of the coil is sufficient. Can be.

  Japanese Patent Application Laid-Open No. 11-206063 (Patent Document 3) discloses an electric motor that is incorporated in a power transmission device and that is cooled using cooling oil. The electric motor includes an armature core and an armature having an armature coil wound around the armature core, and has an effect of rotating a rotating shaft. The armature covers the armature, and the armature A cover having a gap through which the coolant passes in the vicinity of the coil end, which is a portion of the coil protruding in the axial direction from the armature core, and a heat transfer member that enables heat transfer from the coil end to the cover; A supply oil passage for supplying a coolant to the gap between the armature core and the cover is provided during rotation of the electric motor. The gap through which the coolant passes is a gap formed by a groove formed in the cover, and a partition plate that partitions the groove from the coil end, and the heat transfer member transmits heat between the coil end and the partition plate. It is a resin molded member so as to be possible.

  According to the electric motor disclosed in Patent Document 3, since the refrigerant path is formed by both the groove portion and the partition plate formed in the cover, the refrigerant path can be easily processed. Further, by filling (molding) the space between the partition plate and the coil end with resin, it is possible to transfer heat between the two while holding the previously formed refrigerant path. Conventionally, a technology that enables heat transfer to the cover by molding the coil end with resin has been known, but it can be molded with the partition plate leaving the refrigerant path in the vicinity of the coil end. It became. As a result, the coil end can be cooled very efficiently.

  Japanese Patent Application Laid-Open No. 5-235704 (Patent Document 4) discloses a motor cooling device that effectively cools the stator that is most likely to have the highest temperature in the motor and efficiently cools the motor according to the driving state of the motor. Is disclosed. This motor cooling device is a motor cooling device having a stator installed in a motor case and a rotor installed on a rotating shaft of the motor, and is provided along the axial direction in the rotating shaft of the motor. The cooling refrigerant supply path is opposed to the stator coil end formed by the winding wound around the stator core, and the cooling refrigerant is provided to be ejected from the cooling refrigerant supply path to the stator coil end. A cooling refrigerant jet hole, a pump for supplying the cooling refrigerant to the cooling refrigerant supply passage, and a pump control means for changing the amount of the cooling refrigerant discharged from the pump according to the driving state of the motor are provided.

According to the motor cooling device disclosed in Patent Document 4, since the cooling refrigerant ejection hole is provided on the rotating shaft of the motor so as to face the stator coil end, the cooling refrigerant discharged by the pump is supplied to the stator coil end. Can be applied directly. Furthermore, since the temperature of the stator coil end changes according to the driving state of the motor, the amount of refrigerant is changed according to the driving state of the motor. As a result, the stator coil end that is most likely to have the highest temperature in the motor is directly cooled, and as a result, the entire motor is efficiently cooled.
Japanese Utility Model Publication No. 54-607 JP 2003-9467 A JP-A-11-206063 JP-A-5-235704

  However, the technique disclosed in the above publication has the following problems.

  In the cooling device disclosed in Patent Document 1, cooling oil is supplied to a hollow rotating shaft, and the cooling oil is sprayed in a direction perpendicular to the rotating shaft and away from the rotating shaft. In this direction, the coil end of the rotor (rotor) and the coil and coil end of the stator (stator) are arranged. However, the sprayed cooling oil is scattered immediately and the cooling efficiency is not good. In particular, since the rotor coil end is located on the inner side of the rotating shaft than the stator coil and coil end, the possibility of cooling oil reaching the stator coil and coil end directly is low, and the cooling efficiency of the stator is preferable. Absent.

  In the motor cooling structure disclosed in Patent Document 2, cooling oil is dropped from the rotating shaft of the motor through the rotor to the stator coil and coil end. The cooling oil dropped on the coil end of the stator does not stay and falls, for example, into an oil pan disposed at the bottom. Therefore, the stator coil end cannot be sufficiently cooled.

  In the electric motor disclosed in Patent Document 3, in order to efficiently cool the coil end of the stator, an oil passage is formed in the vicinity of the coil end while the coil end is molded with resin. When molding with resin, a groove that forms part of the oil passage is formed near the coil end, and the groove is sealed with an O-ring and then closed with a partition plate. In this way, an oil passage through which cooling oil flows is formed in the coil end, and the coil end is molded with resin, so that heat exchange by heat transfer with the cooling oil passage is possible. The end is cooled by this cooling oil. However, molding the stator coil end with resin while forming the oil passage in the vicinity thereof makes the structure very complicated and requires a great number of man-hours for production. For this reason, it leads to a cost increase. Also, processing in this way increases the weight of the electric motor, and the increase in the vehicle weight ultimately leads to a deterioration in the fuel consumption of the vehicle.

  In the electric motor disclosed in Patent Document 4, the cooling oil is supplied from the rotating shaft to the coil end of the stator where the temperature rises most among the motors. The cooling oil does not stay at the stator coil end, and the supplied cooling oil falls to, for example, an oil pan disposed at the bottom without sufficient heat exchange. Therefore, the stator coil end cannot be sufficiently cooled.

  As described above, in cooling the stator portion with the cooling oil, 1) the cooling shaft is supplied from the rotating shaft to the stator coil end using the centrifugal force generated by the rotation of the motor; I was doing. In 1), the rotor coil end gets in the way and cooling oil is not sufficiently supplied from the rotating shaft to the stator coil end. In 2), the rotating shaft side of the stator coil end (that is, the motor rotating shaft is horizontal) In this cross section, sufficient cooling oil is not supplied to the lower side of the upper stator coil end, so that the stator coil end cannot be sufficiently cooled.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a cooling structure for a rotating electrical machine that can sufficiently cool a stator, a stator coil, and a coil end. .

  A cooling structure for a rotating electrical machine according to a first aspect of the present invention is a cooling structure for a rotating electrical machine having a rotor that rotates about a rotating shaft and a stator that faces the circumferential surface of the rotor, and a cooling medium from the rotating shaft to the stator. Supply means for supplying the cooling medium, and holding means for holding the cooling medium supplied from the supply means by the stator.

  According to the first aspect of the invention, the supply means sprays cooling oil, which is a cooling medium, for example, from the opening provided in the rotating shaft in the stator direction (outer peripheral direction) through the hollow portion with the rotating shaft as the hollow shaft. To do. As the holding means, a holding member having a shape capable of holding the cooling oil sprayed from the supply means by the stator is provided. The holding member is, for example, a member that has a concave portion in the direction of the rotation axis, is provided on the outer peripheral side of the stator, guides the sprayed cooling oil to the stator, and allows the stator to hold the cooling oil. Thereby, a stator can be cooled efficiently. As a result, it is possible to provide a cooling structure for a rotating electrical machine that can sufficiently cool the stator, the stator coil, and the coil end.

  In the cooling structure for a rotating electrical machine according to the second invention, in addition to the configuration of the first invention, the holding means is provided on the outer peripheral side of the stator.

  According to the second invention, the holding means provided on the outer peripheral side prevents the cooling oil sprayed from the rotating shaft toward the outer periphery from reaching the housing part beyond the stator and the stator coil end, thereby spraying. The cooled cooling oil is guided to the stator, and the stator can hold the cooling oil. Thereby, a stator can be cooled efficiently.

  In the cooling structure for a rotating electrical machine according to the third aspect of the invention, in addition to the configuration of the first aspect of the invention, the holding means is formed by a stator coil.

  According to the third invention, the holding means has a shape of the stator coil end, for example, a shape having a recess in the direction of the rotation axis, and the sprayed cooling oil is held in the stator coil end itself. it can. Thereby, a stator coil end can be cooled efficiently.

  In the rotating electrical machine cooling structure according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the cooling medium is a cooling liquid, and the supply means sprays the cooling medium. Including means.

  According to the fourth aspect of the invention, the stator coil end can be efficiently cooled using the liquid having a high cooling efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  In the following description, the rotating electrical machine in the present invention is described as an electric motor, but the present invention is not limited to the electric motor and is not applied. For example, you may make it apply to generators, such as a generator and an alternator.

  With reference to FIG. 1, the electric motor mounted in the vehicle which concerns on embodiment of this invention is demonstrated. It is assumed that the vehicle is mounted on the vehicle with the rotating shaft shown in FIG. 1 being horizontal or substantially horizontal.

  FIG. 1 shows a cross-sectional view of such an electric motor (where the rotating shaft represents the outer shape). This electric motor includes a rotor part including a rotor 1010 rotatably supported by two bearings 1020 and a stator part including a stator core 2000 installed in the outer peripheral direction of the rotor 1010. The rotor 1010 is supported by a bearing 1020, rotates about the rotation shaft 1000, and transmits rotational torque to the power train of the vehicle.

  A stator core 2000 is provided at a position corresponding to the rotor 1010 via a slight gap. A coil is wound around the stator core 2000 in a slit provided so as to penetrate the stator core 2000 in a direction parallel to the rotation shaft 1000. End portions of the stator coil wound around the stator core 2000 are formed as coil ends 2010 on both sides of the stator core 2000.

  The stator coil is provided so as to be covered with insulating paper provided in a slot of the stator core 2000. Teeth are formed between the slots.

  A current is passed through the coil wound around the stator core 2000, and the stator core 2000 generates a magnetic field for rotating the rotor 1010. At this time, Joule heat is generated by the current flowing in the stator coil, and the stator core 2000, the stator coil, and the stator coil end generate heat.

  The rotor 1010 may be configured by laminating a large number of electromagnetic steel plates (thin plates of about 0.2 mm to 0.5 mm), or may be an integral one. Note that the rotating shaft 1000, the rotor 1010, the bearing 1020, the stator core 2000, the stator coil end 2010, and the like, which are these components, are housed in the housing 3000.

  The rotating shaft 1000 will be described in detail with reference to FIG. FIG. 2 is an enlarged view of the rotor and the rotating shaft portion of FIG. FIG. 2 is a cross-sectional view of the rotating shaft 1000 and the rotor 1010. The rotating shaft 1000 of the rotor 1010 is composed of an inner hollow shaft 1100 (oil pump shaft) and an outer hollow shaft 1200 (rotor shaft). A hollow portion of the inner hollow shaft 1100 is a rotating shaft cooling oil passage 1102. The rotating shaft cooling oil passage 1102 is connected to an oil pump (not shown), and cooling oil is supplied to the rotating shaft cooling oil passage 1102, and an oil passage 1104 in a direction perpendicular to the rotating shaft provided in the inner hollow shaft 1100 and The inside of the housing 3000 is sprayed through the opening 1202 of the outer hollow shaft 1200.

  Cooling oil is sprayed from the opening 1202 in a direction perpendicular to the rotation shaft 1000. As indicated by arrows A and B in FIG. 2, the cooling oil flows to the outer peripheral side along the side surface of the rotor 1010 by centrifugal force and is supplied to the stator core 2000 and the stator coil end 2010. At this time, the cooling oil cools the rotating shaft itself (the inner hollow shaft 1100 and the outer hollow shaft 1200) by exchanging heat with the rotor 1010, the stator core 2000, the stator coil, and the stator coil end 2010. To do.

  The cooling oil that has cooled the stator core 2000, the stator coil, and the stator coil end 2010 is stored in an oil pan provided below the housing 3000, and is supplied again to the rotating shaft cooling oil passage 1102 by the oil pump. That is, the cooling oil is circulated and used by the oil pump.

  With reference to FIG. 3, the flow of the cooling oil that has reached stator core 2000 and stator coil end 2010 will be described. 3 shows only the upper half portion from the rotating shaft 1000, the lower half may have the same configuration, or only the upper half may have the configuration shown in FIG.

  As shown in FIG. 3, a cooling oil holding member 2500 is provided in the housing 3000 of the electric motor. The cooling oil holding member 2500 has a concave shape on the outer peripheral side of the stator coil end 2010 and opened in the direction of the rotating shaft 1000 so as to surround the stator coil end 2010. The stator coil end 2010 is outside the stator core 2000 of the stator coil that is included in the insulating paper provided in the slot of the stator core 2000 and wound around the slot, and this portion is mainly cooled by the cooling oil. .

  The cooling of the heat generated in the stator coil end 2010 by flowing a current through the coil of the stator core 2000 in the electric motor having the above structure will be described.

  In order for the electric motor to rotate about the rotation shaft 1000 and drive the vehicle, a predetermined current (for example, a current for generating a torque required for running the vehicle) is generated in the coil of the stator core 2000. Will be washed away. At this time, the stator coil end 2010 generates heat or heat generated in the stator core 2000 is thermally conducted to the stator coil end 2010 by this current, and the stator coil end 2010 generates heat.

  At this time, the cooling oil is supplied from the oil pump through the rotating shaft cooling oil passage 1102 of the rotating shaft 1000 which is a hollow shaft. The cooling oil that has passed through the rotating shaft cooling oil passage 1102 reaches the opening 1202 through an oil passage 1104 that is perpendicular to the rotating shaft.

  The cooling oil sprayed onto the housing 3000 from the opening 1202 receives a centrifugal force due to the rotation of the rotor 1010 as shown by arrows A and B in FIG. 2, and the outer peripheral surface of the rotor 1010 along the outer periphery of the rotor 1010. To move. Cooling oil is splashed from the end face of the rotor 1010 onto the stator coil end 2010 as shown by an arrow C in FIG. At this time, for example, as shown by an arrow D in FIG. 3, the cooling oil hits the cooling oil holding member 2500 and is supplied to the stator coil end. Further, the cooling oil is held in a gap between the cooling oil holding member 2500 and the stator coil end 2010. Such a situation can be similarly generated on the opposite side shown in FIG. 3 (the lower side of the electric motor shown in FIG. 3).

  As described above, according to the electric motor according to the present embodiment, the stator having the hollow cylindrical shape, the rotatable rotor having the cylindrical shape arranged on the inner peripheral side of the hollow portion of the stator, and the rotating shaft of the rotor It consists of. Cooling oil is supplied in the outer circumferential direction from the rotary shaft, and the cooling oil holding member holds the cooling oil in the stator coil end, the stator coil, and the stator. For this reason, the cooling oil can sufficiently cool the stator coil end, the stator coil, and the stator. In an electric motor that cools a stator by supplying a cooling medium from a rotating shaft of a rotor, a stator coil end and the like can be efficiently cooled with a simple structure.

  FIG. 4 shows the flow of cooling oil in the stator of the electric motor according to the modification of the embodiment of the present invention. FIG. 4 corresponds to FIG. 3 described above. Since other structures (for example, the internal structure of rotating shaft 1000) are the same as those shown in FIGS. 1 and 2, detailed description thereof will not be repeated here.

  In the electric motor according to the modification shown in FIG. 4, the function of the cooling oil holding member 2500 shown in FIG. 3 is realized by changing the shape of the stator coil end 2012 itself. As shown in FIG. 4, the stator coil end 2012 is molded so as to have at least a concave shape opened in the direction of the rotation shaft 1000. Specifically, since the stator coil end 2012 is a folded portion of the stator coil wound around the slot of the stator core 2000, the folded portion is molded into a shape as shown in FIG.

  In this way, the cooling oil sprayed to the housing 3000 from the opening 1202 receives the centrifugal force due to the rotation of the rotor 1010 and moves to the end surface of the rotor 1010 as shown by arrows A and B in FIG. Cooling oil is splashed from the end face of the rotor 1010 onto the stator coil end 2012 as shown by an arrow E in FIG.

  As described above, according to the electric motor according to the present modification, the stator coil end itself has a shape that can hold the cooling oil. Therefore, the stator coil end can be cooled sufficiently by holding the cooling oil. As a result, the stator coil end and the like can be efficiently cooled with a simple structure in an electric motor that cools the stator by supplying a cooling medium from the rotating shaft of the rotor.

  The embodiment 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, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is sectional drawing of the electric motor which concerns on embodiment of this invention. It is an enlarged view of a rotor and a rotating shaft part. It is a figure which shows the flow of the cooling oil in a stator. It is a figure which shows the flow of the cooling oil in the stator of the electric motor which concerns on the modification of embodiment of this invention.

Explanation of symbols

  1000 rotating shaft, 1010 rotor, 1020 bearing, 2000 stator core, 2010, 2012 stator coil end, 2500 cooling oil holding member, 3000 housing.

Claims (4)

A cooling structure for a rotating electrical machine having a rotor that rotates about a rotation axis and a stator that faces the circumferential surface of the rotor,
Supply means for supplying a cooling medium from the rotating shaft to the stator;
A rotating electrical machine cooling structure, comprising: a holding means for holding the cooling medium supplied from the supply means by the stator.   The cooling structure for a rotating electrical machine according to claim 1, wherein the holding unit is provided on an outer peripheral side of the stator.   The cooling structure for a rotating electric machine according to claim 1, wherein the holding means is formed by a stator coil. The cooling medium is a cooling liquid,
The cooling structure for a rotating electrical machine according to any one of claims 1 to 3, wherein the supply means includes means for spraying the cooling medium.

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