JP2011217438A - Cooling system for rotating electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively cool a rotating electric machine.SOLUTION: A cooling system is provided with a cooling oil pipe 18 to cool a cooling oil. In the cooling pipe 18, a discharge port 26b, which is opened in a direction just facing a coil end 14a or 14b, and discharge ports 26a and 26c, which are opened toward a direction not just facing the coil end 14a or 14b at positions deviated in the circumferential direction of the cooling oil pipe 18 from the discharge port 26b, are created to discharge the cooling oil toward the periphery of the coil end 14a or 14b. At this time, the discharge ports 26a and 26c are made larger in diameter than the discharge port 26b.

Description

  The present invention relates to a cooling device for a rotating electrical machine. In particular, the present invention relates to a cooling device for a rotating electric machine that cools a stator coil with a cooling medium such as cooling oil.

  When a current flows through a coil of a rotating electrical machine such as a motor or a generator, the coil generates heat and the efficiency of the rotating electrical machine decreases. Therefore, a cooling device for properly cooling the generated coil is required. Therefore, a cooling device for a rotating electrical machine that cools a coil end or the like of a stator coil with cooling oil is disclosed.

  Patent Document 1 discloses a cooling device for a rotating electrical machine that includes a cooling oil jet opening that opens downward along a direction parallel to a rotation axis above a stator core and a coil end of the stator. Here, in order to increase the amount of cooling oil supplied to the coil end rather than the stator core, the cooling oil outlet directed toward the coil end is made larger than the cooling oil outlet directed toward the stator core.

  In Patent Document 2, the cooling oil pipe for supplying cooling oil to the coil end and the discharge hole are arranged so that the cooling oil enters at an incident angle θ1 of 25 degrees or more and 30 degrees or less with respect to the tangent at the oiling point. Techniques to do this are disclosed.

JP 2008-263653 A JP 2006-115651 A

  However, in the technique disclosed in Patent Document 2, all the cooling oil jet nozzles are provided with the same hole diameter, and the amount of oil is insufficient on the side surface of the coil end, so that the coil end portion cannot be sufficiently cooled. was there.

  One aspect of the present invention is a cooling device for a rotating electric machine that cools a coil end formed at an end portion of a stator core in a rotation axis direction with a cooling medium, and includes a cooling medium path for supplying the cooling medium. The cooling medium path has a first discharge hole opened in a direction facing the coil end in order to discharge the cooling medium toward the outer peripheral surface of the coil end, and the first discharge hole. And a second discharge hole opened in a direction not facing the coil end at a position shifted in the circumferential direction of the cooling medium path, wherein the second discharge hole is the first discharge hole. It has a larger opening diameter than the hole.

  Here, it is preferable that the number of the second discharge holes is larger than the number of the first discharge holes.

  The cooling medium path includes a third discharge hole opened in a direction facing the stator core, and the discharge hole is provided at a position shifted from the third discharge hole in the circumferential direction of the cooling medium path. It is preferred not to.

  According to the present invention, the rotating electrical machine can be effectively cooled.

It is a section side view of the cooling device of the rotating electrical machine in the embodiment of the present invention. It is a figure explaining arrangement | positioning of the discharge hole in embodiment of this invention. It is a figure explaining another example of arrangement | positioning of the discharge hole in embodiment of this invention.

  FIG. 1 shows an internal side view of a cooling device 100 for a rotating electrical machine according to an embodiment of the present invention. FIG. 2 is a partially enlarged cross-sectional view taken along line XX in FIG.

  The rotating electrical machine cooling device 100 includes a stator core 10, a rotor 12, coil ends 14 a and 14 b, a rotating shaft 16, a cooling oil pipe 18, and a device case 20.

  The stator core 10 is formed by laminating and crimping electromagnetic steel plates in the direction of the rotation axis. The stator core 10 is installed in the device case 20. A coil 24 for forming a stator magnetic field is wound around the stator core 10. The rotor 12 is attached to the rotating shaft 16. The rotating shaft 16 is a rotating shaft of the rotating electric machine that rotates in conjunction with the rotor 12. The rotating shaft 16 is installed in the device case 20 so that the rotor 12 can rotate in the device case 20.

  A permanent magnet for forming a rotor magnetic field is disposed inside the rotor 12. Due to the interaction between the rotor magnetic field formed by the rotor 12 and the stator magnetic field formed by passing a current through the coil 24 of the stator core 10, the rotor 12 rotates around the rotation axis in conjunction with the rotation shaft 16.

  The coil ends 14 a and 14 b are formed on both sides of the stator core 10 in the rotation axis direction by the coils 24 wound around the stator core 10.

  The cooling oil pipe 18 is an oil supply pipe for supplying cooling oil for cooling the stator core 10 including the coil ends 14a and 14b. The cooling oil pipe 18 can be made of, for example, a plastic material such as vinyl chloride or a metal such as stainless steel. When the cooling oil pipe 18 is made of plastic such as vinyl chloride, a necessary shape can be obtained using a mold. The cooling oil pipe 18 is disposed above the stator core 10 and the coil ends 14 a and 14 b along the rotation axis of the rotation shaft 16. In particular, as shown in FIG. 2, the cooling oil pipe 18 is preferably arranged along a perpendicular line L <b> 1 passing through the center of the rotation shaft of the rotation shaft 16. The cooling oil pipe 18 is provided with discharge holes 26a, 26b, and 26c so as to be positioned at least above the coil ends 14a and 14b in the rotation axis direction, respectively. The discharge holes 26a, 26b, and 26c are preferably provided above both the coil ends 14a and 14b. Further, a discharge hole 26d or the like may be provided at a place other than above the coil ends 14a and 14b.

  The cooling oil pipe 18 is connected to an oil pump (not shown) and supplies cooling oil into the cooling oil pipe 18. The oil pump includes, for example, a mechanical gear pump or an electric pump. By moving the oil pump, the cooling oil discharged from the discharge holes 26a, 26b, and 26c is supplied to the coil ends 14a and 14b from above the coil ends 14a and 14b through the cooling oil pipe 18, respectively.

  FIG. 2 also shows the locus of the cooling oil 28 discharged from the discharge holes 26a, 26b, and 26c of the cooling oil pipe 18. In addition, since the locus | trajectory of discharge of the cooling oil 28 from the discharge holes 26a, 26b, and 26c provided in the cooling oil pipe 18 is the same in any place, it is above the coil end 14a here. The provided discharge holes 26a, 26b, and 26c will be described representatively.

  As shown in FIG. 2, the discharge hole 26 b is opened at a position facing the coil end 14 a of the cooling oil pipe 18. For example, when the cooling oil pipe 18 is installed above the stator core 10, it may be opened vertically downward. Thereby, the cooling oil 28 discharged from the discharge hole 26b reaches the uppermost point B of the coil end 14a. Further, the discharge holes 26a and 26c are opened at positions that are shifted in the circumferential direction of the cooling oil pipe 18 from positions that face the discharge holes 26b. For example, when the cooling oil pipe 18 is installed above the stator core 10, the cooling oil pipe 18 is opened obliquely downward. The cooling oil 28 discharged from the discharge holes 26a and 26c is applied to oil landing points A and C that are shifted from the uppermost point B of the coil end 14a in both circumferential directions.

  The cooling oil 28 discharged from the discharge hole 26b flows down below the coil end 14a. Further, the cooling oil 28 discharged from the discharge holes 26a and 26c also flows down toward the lower side of the coil end 14a while traveling on the outer periphery of the coil end 14a. At this time, the cooling oil 28 flows down below the coil end 14b while taking heat from the coil end 14b.

  Here, it is preferable that the discharge holes 26a and 26c have a larger diameter than the discharge hole 26b. Specifically, the hole diameters of the discharge holes 26a and 26c are more preferably 1.1 times to 2 times the hole diameter of the discharge holes 26b. Thus, by providing the discharge holes 26a and 26c having the oil landing points A and C on the side surfaces of the coil ends 14a and 14b, and making the diameter of the discharge holes 26a and 26c larger than the diameter of the discharge hole 26b, A large amount of cooling oil 28 can be supplied to the coil ends 14a and 14b that require a large amount of oil for cooling, and the side surfaces of the coil ends 14a and 14b can be effectively cooled.

  Further, instead of or in addition to making the hole diameters of the discharge holes 26a and 26c larger than the hole diameter of the discharge hole 26b, the number of the discharge holes 26a and 26c is set to the number of the discharge holes 26b as shown in FIG. It may be more than the number. In this case, it is more preferable that the total area of each of the discharge holes 26a and 26c is larger than the total area of the discharge holes 26b. For example, when one discharge hole 26b is provided, it is preferable to provide two discharge holes 26a and 26c each having the same size as the discharge hole 26b. As a result, as in the case where the hole diameters of the discharge holes 26a and 26c are larger than the hole diameter of the discharge hole 26b, more cooling oil 28 can be supplied to the side surfaces of the coil ends 14a and 14b. , 14b can be effectively cooled. Moreover, since the hole diameters of the discharge holes 26a, 26b, and 26c are the same and the opening area can be adjusted by the number of holes, the processing becomes easier.

  The cooling oil pipe 18 and the discharge holes 26a and 26c are preferably arranged so that the incident angle of the cooling oil 28 to the coil ends 14a and 14b is θ1, as shown in FIG. That is, the cooling oil 28 discharged from the discharge holes 26a and 26c of the cooling oil pipe 18 is incident on the tangent L3 of the outer circumference of the coil end 14a or 14b at the oil landing points A and C at an incident angle θ1. .

  It is preferable that the incident angle θ1 is determined so that the oil landing rate of the cooling oil 28 on the coil ends 14a and 14b is maximized. And, in order to maximize the rate of the cooling oil 28 landing on the coil ends 14a, 14b, it is desirable that the incident angle θ1 of the cooling oil 28 on the coil ends 14a, 14b is 25 ° or more and 30 ° or less. When the incident angle θ1 of the cooling oil 28 to the coil ends 14a and 14b is an acute angle than 25 °, the cooling oil 28 having a certain flow velocity u collides with the oil landing points A and C of the coil ends 14a and 14b. The amount of reflection on the surfaces of the coil ends 14a and 14b and jumping to the outside of the coil ends 14a and 14b increases. Therefore, the oil deposit rate of the cooling oil 28 to the coil ends 14a and 14b is lowered. On the other hand, when the incident angle θ1 of the cooling oil 28 to the coil ends 14a and 14b is an obtuse angle than 30 °, the cooling oil 28 having a certain flow velocity u reaches the oil landing points A and C of the coil ends 14a and 14b. When the collision occurs, the amount of the cooling oil 28 scattered from the coil ends 14a and 14b to the outside increases. Therefore, the oil deposit rate of the cooling oil 28 to the coil ends 14a and 14b is lowered. As described above, the oil oil landing rate of the cooling oil 28 to the coil ends 14a and 14b becomes the maximum when the incident angle θ1 of the cooling oil 28 to the coil ends 14a and 14b is in the range of 25 ° to 30 °.

  Further, the cooling oil pipe 18 and the discharge holes 26a, 26c are such that the oil landing points A, C of the cooling oil 28 discharged from the discharge holes 26a, 26c are from the uppermost point B of the coil ends 14a, 14b to the coil ends 14a, 14b. It is preferable to arrange so that the position is inclined by an angle θ2 in the circumferential direction. That is, the cooling oil pipe 18 and the coolant oil pipes 18 and 18 are set so that the points where the straight line L2 obtained by rotating the perpendicular L1 about the rotation axis by the angle θ2 intersects the outer circumference circles of the coil ends 14a and 14b are the landing points A and C of the cooling oil Discharge holes 26a and 26c are provided.

  This angle θ2 is preferably determined so that the oil coverage of the coil ends 14a, 14b by the cooling oil 28 is maximized. In order to maximize the oil coverage of the coil ends 14a and 14b by the cooling oil 28, the angle θ2 may be set to approximately 30 °. When the inclination angle θ2 that defines the oil landing points A and C of the cooling oil 28 to the coil ends 14a and 14b is an acute angle of more than 30 °, the cooling oil 28 discharged from the cooling oil pipe 18 has the oil landing points A and C. When oil is applied to C, the cooling oil 28 penetrates through the coil ends 14a and 14b without passing through the annular coil ends 14a and 14b. Therefore, the oil coverage of the coil ends 14a and 14b by the cooling oil 28 becomes very small, and the cooling function of the coil ends 14a and 14b by the cooling oil 28 is not sufficient. Further, since a large amount of the cooling oil 28 flows into the rotor 12, the viscosity of the cooling oil 28 causes rotational resistance of the rotor 12, which may deteriorate the efficiency of the rotating electrical machine. On the other hand, when the inclination angle θ2 is an obtuse angle than 30 °, when the cooling oil 28 discharged from the cooling oil pipe 18 reaches the oil landing points A and C, the cooling oil travels down the coil ends 14a and 14b. To flow down. However, in the range where the inclination angle θ2 is smaller than 30 °, that is, on the upper side of the coil ends 14a and 14b between the oil landing points A and C on both sides, the cooling oil 28 is not supplied and the coil end 14a as a whole. 14b cannot be increased.

  In addition, in the region of the stator core 10 other than above the coil ends 14a and 14b, it is preferable to provide the discharge holes 26d in the cooling oil pipe 18 one by one along the extending direction of the cooling oil pipe 18. In other words, in regions other than the coil ends 14 a and 14 b, it is preferable not to provide discharge holes at positions shifted in the circumferential direction of the discharge holes 26 d and the cooling oil pipe 18. For example, the discharge hole 26d may be provided at a position facing the stator core 10 of the cooling oil pipe 18. That is, when the cooling oil pipe 18 is installed above the stator core 10, it may be opened vertically downward. This is because in a region other than the coil ends 14a and 14b, if the discharge hole 26d is provided vertically downward, a sufficient amount of cooling oil necessary for cooling can be supplied to the stator core 10. Moreover, the processing steps of the cooling device 100 for the rotating electrical machine can be reduced and the manufacturing cost can be reduced without providing many discharge holes 26d unnecessarily.

  Further, in the present embodiment, the cooling oil pipe 18 for supplying the cooling oil is disposed above the uppermost vertical point of the stator core 10 and the coil ends 14a and 14b, and consists of a single pipe. However, the present invention is not limited to this, and a plurality of cooling oil pipes 18 may be used. For example, a plurality of cooling oil pipes 18 may be arranged side by side along the rotation axis direction of the rotor 12 vertically above the stator core 10 and the coil ends 14a and 14b. Furthermore, although the cooling oil pipe 18 is fixed to the apparatus case 20, it may be fixed to the stator core 10.

  Moreover, the cooling device for a rotating electrical machine according to the present invention is suitable for a hybrid vehicle (Hybrid Vehicle) and an electric vehicle (Electric Vehicle) which have attracted much attention in recent years. A hybrid vehicle is a vehicle that uses a DC power source, an inverter, and a rotating electrical machine (motor generator) driven by the inverter as a power source in addition to an engine. An electric vehicle is a vehicle that uses a DC power source, an inverter, and a rotating electrical machine (motor generator) driven by the inverter as a power source. Such vehicles such as hybrid vehicles and electric vehicles require various characteristics such as high output, low fuel consumption, small size, low cost, and high reliability. According to the cooling device 100, the cooling performance of the rotating electrical machine is improved, so that the rotating electrical machine can be driven with a higher load, and as a result, higher output of the vehicle can be realized. Further, effective cooling can suppress a reduction in the efficiency of the rotating electrical machine, and as a result, a reduction in fuel consumption of the vehicle can be realized. Furthermore, since it does not accompany an increase in the size of the rotating electrical machine, it can contribute to reducing the size, weight, and cost of the vehicle. Furthermore, the reliability of the rotating electrical machine is improved by sufficiently ensuring the cooling performance of the rotating electrical machine.

  DESCRIPTION OF SYMBOLS 10 Stator core, 12 Rotor, 14a, 14b Coil end, 14b Coil end, 16 Rotating shaft, 18 Cooling oil pipe, 20 Apparatus case, 24 Coil, 26a, 26b, 26c, 26d Discharge hole, 28 Cooling oil, 100 Cooling device.

Claims (3)

A cooling device for a rotating electrical machine that cools a coil end formed at an end portion of a stator core in a rotation axis direction with a cooling medium,
A cooling medium path for supplying the cooling medium;
The cooling medium path includes a first discharge hole opened in a direction facing the coil end in order to discharge the cooling medium toward the outer peripheral surface of the coil end, and the first discharge hole. A second discharge hole opened toward a direction not facing the coil end at a position shifted in the circumferential direction of the cooling medium path,
The cooling device for a rotating electric machine, wherein the second discharge hole has a larger opening diameter than the first discharge hole. The cooling device for a rotating electric machine according to claim 1,
The number of the second discharge holes is larger than the number of the first discharge holes. A cooling device for a rotating electrical machine according to claim 1 or 2,
The cooling medium path includes a third discharge hole opened in a direction directly opposite to the stator core, and no discharge hole is provided at a position shifted in the circumferential direction of the third discharge hole and the cooling medium path. A cooling device for a rotating electric machine.

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