JP2006006091A - Cooling device for motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device for a motor which removes magnetic foreign matters in cooling oil, prevents deterioration in the insulation performance of a coil caused by damage to an insulating film of a coil surface, and is higher in electrical, magnetic or mechanical reliability. <P>SOLUTION: The cooling device for the motor comprises a rotor with a permanent magnet extended in the rotating shaft direction of the motor, and a stator wound with the coil. The cooling device also includes a feeding means of feeding cooling oil to cool the motor, and an oil pass 21 with an injection port 19 for injecting a cooling medium to a permanent magnet 15 extended toward the end of the rotor in the rotating shaft direction of the motor. The magnetic foreign matter 101 contained in the cooling oil is attracted by a magnetic force to the vicinity of the permanent magnet 15 of the end of the rotor in the rotating shaft direction of the motor to be adsorbed. The magnetic foreign matter is removed from the cooling oil; and deterioration in the insulation performance of the motor is prevented without damaging the insulating film of the coil even if the cooling oil is dropped or injected to a coil end 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cooling device for an electric motor, and in particular, removes magnetic impurities from cooling oil dripping or spraying on a coil to prevent deterioration of the insulating performance of the coil due to damage to the insulating film on the coil surface. TECHNICAL FIELD The present invention relates to a motor cooling device with high mechanical, magnetic or mechanical reliability.

  2. Description of the Related Art Conventionally, in an electric motor including a rotor and a stator, an electric motor cooling device that cools a coil by dropping cooling oil onto a coil end of a coil provided in the stator is known.

For example, Japanese Patent Laid-Open No. 5-122903 discloses a configuration for cooling a motor as a drive device for an electric vehicle. In this conventional example, an oil circulation means (oil pump) that circulates cooling oil in a case housing the motor is added with a function of changing the oil circulation amount in accordance with the heat generated by the motor. While maintaining the proper, efficient cooling according to the output status of the motor is realized.
JP-A-5-122903

  However, the technique disclosed in Patent Document 1 described above has a structure in which an oil circulation means (oil pump) and a cooling oil passage are provided to cool the electric motor, leading to an increase in cost. Therefore, for example, it is conceivable to use a lubricating oil for a transmission or the like as a cooling oil for an electric motor. In this case, the lubricating oil for the transmission is a small magnetic metal piece such as iron (hereinafter referred to as iron) generated by meshing of gears or the like. When the cooling oil is dropped or sprayed on the coil to cool the coil, the insulating coating on the coil surface is damaged by the magnetic contaminant, and the insulation performance of the coil is reduced. There was a risk of decline.

  The present invention has been made in view of the above-described conventional circumstances, and the magnetic contaminants of the cooling oil dripping or spraying on the coil are removed, and the insulating film on the coil surface is damaged. It is an object of the present invention to provide a motor cooling device that prevents the above-described problem.

  In order to solve the above-mentioned object, the present invention provides a cooling device for an electric motor having a rotor having a permanent magnet extending in the direction of the electric motor rotating shaft and a stator around which a coil is wound. A supply means for supplying a medium, and a medium passage provided with a jet outlet for injecting the cooling medium toward a permanent magnet extending to an end portion of the rotor in the motor rotation axis direction. .

  In the motor cooling device according to the present invention, the magnetic contaminants contained in the cooling medium are attracted and attracted by the magnetic force to the vicinity of the permanent magnet at the end of the rotor rotation axis of the rotor, and the magnetic contaminants are extracted from the cooling medium. Even if the cooling medium is dropped or sprayed on the coil end, the insulation coating of the coil is not damaged, and the insulation performance of the motor can be prevented from being lowered, and the electrical reliability can be improved. it can.

  Hereinafter, embodiments of the motor cooling device of the present invention will be described in detail in the order of [first embodiment], [second embodiment], [third embodiment], and [fourth embodiment] with reference to the drawings. explain.

First embodiment

  FIG. 1 is a structural diagram illustrating the structure of a motor cooling device according to a first embodiment of the present invention. In the figure, 11 is a rotor core, 12 is a stator core, 13 is a shaft, 14 is a coil end, 15 is a permanent magnet, 16 is a pressing plate, 17 is a wall for fixing a bearing, 18 is a cooling oil for cooling the coil end 14 A supply port, 20 is an oil passage for cooling oil from the supply port 18, 19 is an outlet for cooling oil via an oil passage in the wall 17, 21 is an oil passage for cooling oil injected from the outlet 19, and 27 is A bearing 101 is a magnetic contaminant.

  The stator core 12 is fixed to a motor case (not shown), and the wall 17 is formed by a part of the motor case.

  In FIG. 1A, an electric motor having a shaft 13, a rotor core 11, a pressing plate 16, and a rotor having a permanent magnet 15 extending in the direction of the motor rotation axis, and a stator having a wound coil and a stator core 12. For ease of understanding, the wall 17, the jet outlet 19, and the bearing 27 are shown in a sectional view, and the other parts are shown in a perspective view.

  The motor cooling device of the present embodiment cools the coil end 14 with the cooling oil from the supply port 18 (oil path 20). The oil path is provided in a wall 17 that fixes the bearing of the shaft 13 of the motor to a known cooling structure. , And a jet port 19 is formed at a position opposite to the permanent magnet 15 extending at the end of the rotor in the direction of motor rotation axis, and the end surface of the rotor core 11 (extending to the end of the rotor in the direction of motor rotation axis) The structure is such that a cooling oil is injected from the direction of the motor rotation axis toward the permanent magnet 15) (oil passage 21).

  FIG. 1B shows a detailed cross-sectional view of the end portion of the rotor in the direction of the motor rotation axis (near part A in FIG. 1A). Although the pressing plate 16 has a function of fixing the rotor core 11, in this embodiment, a nonmagnetic material such as aluminum or stainless steel is used as a material so as not to affect the magnetic characteristics. In FIG. 1B, the cooling oil sprayed from the ejection port 19 hits the holding plate 16, and the magnetic contaminants 101 in the cooling oil are attracted to the holding plate 16 by the force of the magnet on the holding plate 16 near the permanent magnet 15. Is shown.

  FIG. 6 shows a configuration diagram of a hydraulic circuit in the present embodiment. In the figure, 31 is a tank, 32 is a filter, 33 is a pump, 34 is a pressure regulating valve, 35 is a cooler, 36 is a transmission, 37 is an electric motor, and a solid line connecting each component indicates an oil passage. An electric motor in a hybrid vehicle is often arranged adjacent to a transmission or a speed reducer (hereinafter referred to as the transmission 36 as a representative), and the lubricating oil of the transmission 36 is used for cooling the electric motor 37. It is implemented with a conventional electric motor. As shown in FIG. 6, the hydraulic circuit in this case is configured such that an electric motor 37 is added to the hydraulic circuit (portion surrounded by a dotted line) 110 of the transmission 36.

  That is, after the pressure of the lubricating oil stored in the tank 31 is increased by the pump 33, the pressure adjusting valve 34 separates the lubricating oil into an oil path used for shift control and an oil path used for lubricating the transmission 36. In this embodiment, for example, by providing a cooling oil passage for the electric motor 37 in parallel with the lubricating oil passage for the transmission 36, the cooling oil can be guided to the electric motor 37. In addition, the cooling effect of the electric motor 37 can be enhanced by installing the cooler 35 in the previous stage of the cooling oil passage.

  By the way, the lubricating oil of the transmission 36 includes cutting pieces generated during machining of the parts and metal pieces generated by meshing of the gears. These cutting pieces and metal pieces are magnetic impurities whose main component is iron or the like. It is a thing. When such lubricating oil is used as the cooling oil for the electric motor 37, when the cooling oil is dropped or injected from the supply port 18 to the coil end 14, the insulating coating of the coil is damaged by the magnetic impurities, and the insulating performance of the electric motor 37 is reduced. May be reduced.

  The hydraulic circuit shown in FIG. 6 is equipped with a foreign matter removing filter 32, but the finer filter 32 cannot be used to secure the flow rate of the lubricating oil or the cooling oil. Therefore, fine magnetic impurities pass through the filter 32 and cause damage to the insulating coating of the coil of the electric motor 37.

  Therefore, in the motor cooling device of the present embodiment, the cooling oil is supplied from the jet port 19 toward the end surface of the rotor core 11 (permanent magnet 15 extending to the end of the rotor in the motor rotation axis direction) from the motor rotation axis direction. By injecting (oil passage 21), the magnetic contaminants 101 contained in the cooling oil are attracted and attracted to the pressing plate 16 near the permanent magnet 15 by a magnetic force. As a result, even if the magnetic contaminants 101 are removed from the cooling oil and the cooling oil is dropped or injected onto the coil end 14, the insulation coating of the coil is not damaged, and the deterioration of the insulating performance of the electric motor 37 is prevented. And electrical reliability can be improved.

  Further, the permanent magnet 15 of the rotor can be cooled, irreversible demagnetization due to heating can be prevented, and the magnetic reliability can be improved. In addition, since the permanent magnet 15 that is a necessary component of the electric motor is used for removing magnetic impurities, no additional parts are required, and the cost and the size of the apparatus are not increased. Furthermore, since the magnetic impurities 101 are removed, it is possible to prevent the bearing of the transmission 36 of the electric motor 37 from being damaged, and to improve the mechanical reliability.

Second embodiment

  Next, FIG. 2 is a structural diagram of a motor cooling device according to a second embodiment of the present invention. In the figure, 11 is a rotor core, 13b is a shaft, 15 is a permanent magnet, 16 is a pressing plate, 19b is a cooling oil jet through an oil passage in the shaft 13b, 22 is a guide portion, and 21b is from a jet 19b. It is an oil passage for cooling oil that is injected and directed at the guide portion 22. The stator core 12, the coil end 14, and the cooling oil supply port 18 for cooling the coil end 14 are the same as those in FIG.

  In the motor cooling device of this embodiment, an oil passage for the cooling oil is formed in the motor shaft 13b in the direction of the motor rotating shaft, and the jet port 19b is formed in the vicinity of the end of the rotor in the motor rotating shaft direction as a hole in the shaft 13b. This is the structure. In addition, a guide portion 22 that guides cooling oil that is blown off by centrifugal force during motor rotation to the permanent magnet 15 that extends to the motor rotation axis direction end of the rotor is formed at the spout 19b formed in the shaft 13b. Has been.

  In this embodiment as well, the hydraulic circuit is as shown in FIG. 6, but the shaft 13 b of the electric motor 37 is connected to the shaft (not shown) of the transmission 36, and the lubricating oil inside the shaft of the transmission 36 is the electric motor 37. Is supplied to the shaft 13b as cooling oil. The oil used for gear lubrication and motor 37 cooling returns to the tank 31 through the inner wall of the case.

  The cooling oil inside the shaft 13 b of the electric motor 37 receives a force radially outward by the centrifugal force when the electric motor 37 rotates, and is ejected from the outlet 19 b of the shaft 13 b, directed by the guide portion 22, and the end face of the rotor core 11. It is sprayed toward (the permanent magnet 15 extending to the end portion of the rotor in the motor rotation axis direction) (oil passage 21b). As a result, the magnetic contaminant 101 contained in the cooling oil is attracted and attracted to the pressing plate 16 near the permanent magnet 15 by a magnetic force. As a result, even if the magnetic contaminants 101 are removed from the cooling oil and the cooling oil is dropped or injected onto the coil end 14, the insulation coating of the coil is not damaged, and the deterioration of the insulating performance of the electric motor 37 is prevented. And electrical reliability can be improved.

  Further, similarly to the first embodiment, the permanent magnet 15 of the rotor can be cooled, irreversible demagnetization due to heating can be prevented, and magnetic reliability can be improved. In addition, since the permanent magnet 15 that is a necessary component of the electric motor is used for removing magnetic impurities, no additional parts are required, and the cost and the size of the apparatus are not increased. Furthermore, since the magnetic impurities 101 are removed, it is possible to prevent the bearing of the transmission 36 of the electric motor 37 from being damaged, and to improve the mechanical reliability.

Third embodiment

  Next, FIG. 3 is a structural diagram of a motor cooling device according to a third embodiment of the present invention. In the figure, 11 is a rotor core, 13b is a shaft, 15 is a permanent magnet, 16c is a holding plate having an opening 23 for exposing the permanent magnet 15, 19b is a cooling oil via an oil passage in the shaft 13b. An ejection port, 22 is a guide portion, and 21c is an oil passage for cooling oil that is injected from the ejection port 19b and directed by the guide portion 22.

  As in the second embodiment, the motor cooling device of the present embodiment forms an oil passage for cooling oil in the motor shaft 13b in the direction of the motor rotation axis, and rotates the motor from a jet port 19b formed in the shaft 13b. Cooling oil blown by the centrifugal force of the time is directed to the permanent magnet 15 that is directed by the guide portion 22 and extends to the end portion of the rotor in the motor rotation axis direction. However, the second embodiment is different from the second embodiment in that an exposure hole 23 is formed in the pressing plate 16c and a part of the permanent magnet 15 is exposed to the end surface of the rotor in the motor rotation axis direction.

  Here, the cross-sectional shape of the motor inner peripheral side of the exposure hole 23 of the holding plate 16c is constant so as not to prevent the cooling oil sprayed from the jet outlet 19b from contacting the permanent magnet exposed on the end surface of the rotor in the motor rotation axis direction. Further, the motor outer peripheral side cross-sectional shape of the exposure hole 23 does not prevent the cooling oil in contact with the permanent magnet 15 from flowing toward the coil end 14 at the end of the coil in the motor rotation axis direction. A certain angle is given.

  Further, it is desirable that the size of the exposure hole 23 of the pressing plate 16c be set to a size corresponding to a part of the permanent magnet 15 as shown in the detailed sectional view of FIG. As shown in the detailed cross-sectional view of FIG. 4B, when the exposure hole 23 of the pressing plate 16c is sized to be exposed over the entire end surface of the permanent magnet 15, the permanent magnet 15 may fall off in the direction of the motor rotating shaft. In addition, in the state in which the magnetic contaminant 101 is attracted, the N pole and S pole of the permanent magnet 15 are (magnetically) short-circuited, and the magnetic characteristics of the motor may be deteriorated, leading to a decrease in performance. .

  In the present embodiment, the cooling oil inside the shaft 13b of the electric motor 37 is ejected from the outlet 19b of the shaft 13b by the centrifugal force when the electric motor 37 rotates, and is directed by the guide portion 22. Injected toward the end face of the rotor core 11 (permanent magnet 15 extending at the end of the rotor in the direction of the motor rotation axis) (oil passage 21c). As a result, the magnetic contaminants 101 contained in the cooling oil are attracted and attracted by the magnetic force to the exposed hole 23 (exposed surface of the permanent magnet 15) of the pressing plate 16. As a result, even if the magnetic contaminants 101 are removed from the cooling oil and the cooling oil is dropped or sprayed on the coil end 14, the insulation coating of the coil is not damaged and the deterioration of the insulation performance of the electric motor 37 is prevented. The electrical reliability can be improved.

  Further, similarly to the second embodiment, the magnetic reliability and the mechanical reliability can be improved, and there is an effect that the cost is not increased and the apparatus is not enlarged. Compared to the above, since the cooling oil is directly injected onto the exposed surface of the permanent magnet 15, the effect of attracting magnetic contaminants is enhanced, and as a result, the cooling effect can be further enhanced.

  Further, the cross-sectional shape of the exposure hole 23 of the holding plate 16c is provided with an angle, and the cooling oil injected to the side surface of the rotor is further injected into the coil end 14 using the centrifugal force of the electric motor. The cooling effect of 14 can be further enhanced.

Fourth embodiment

  FIG. 5 is a structural diagram of a motor cooling device according to a fourth embodiment of the present invention. In the figure, 11 is a rotor core, 13d is a shaft, 15 is a permanent magnet, 16d is a pressing plate, 24 is a groove portion of the pressing plate 16d, and 21d is an oil passage for cooling oil.

  In the motor cooling device of the present embodiment, the oil passage for the cooling oil is formed in the motor shaft 13d in the direction of the motor rotation axis, as in the second embodiment, but the motor shaft is disposed in the holding plate 16d. The difference is that 13d is provided with an oil passage formed in the direction of the motor rotation axis through a jet port and a groove formed from the motor inner circumferential direction toward the motor outer circumferential direction.

  In this embodiment, the cooling oil inside the shaft 13d of the electric motor 37 is jetted along the groove portion 24 of the pressing plate 16d from the outlet of the shaft 13d by receiving a force radially outward by the centrifugal force when the electric motor 37 rotates. Then, the fuel is injected onto the end surface of the rotor core 11 (exposed surface of the permanent magnet 15 extending at the end of the rotor in the direction of the motor rotation axis) (oil passage 21d). Thereby, the magnetic contaminants 101 contained in the cooling oil are attracted and attracted to the exposed surface of the permanent magnet 15 of the groove portion 24 of the pressing plate 16 by magnetic force (see FIG. 5C). As a result, even if the magnetic contaminants 101 are removed from the cooling oil and the cooling oil is dropped or sprayed on the coil end 14, the insulation coating of the coil is not damaged and the deterioration of the insulation performance of the electric motor 37 is prevented. The electrical reliability can be improved.

  Further, like the second and third embodiments, the magnetic reliability and the mechanical reliability can be improved, and there is an effect that the cost is not increased and the apparatus is not enlarged. Compared with the second or third embodiment, the guide portion of the shaft 13d is unnecessary, so that the size and cost can be reduced.

  Further, the outlet of the groove portion 24 formed in the holding plate 16d on the outer periphery side of the motor has a certain angle so that the cooling oil contacting the permanent magnet flows toward the coil end 14 at the end of the coil in the motor rotation axis direction. The cooling oil sprayed on the side surface of the rotor is further sprayed inside the coil end 14 using the centrifugal force of the electric motor, and the cooling effect of the coil end 14 can be further enhanced. Also in this embodiment, as in the third embodiment (FIG. 4), the size of the exposed surface of the permanent magnet 15 in the groove portion 24 inside the holding plate 16d is the size that a part of the permanent magnet 15 is exposed. It is desirable to do.

  In the first, second, third, and fourth embodiments described above, the cooling medium has been described as the cooling oil. However, the same effect can be achieved even if other cooling medium is used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a structural diagram illustrating a structure of a motor cooling device according to a first embodiment of the present invention. It is a block diagram of the cooling device of the electric motor which concerns on 2nd Example. It is a structural diagram of the cooling device for the electric motor according to the third embodiment. It is detailed sectional drawing of the exposure hole 23 of the pressing plate 16c. It is a structural diagram of the cooling device for the electric motor according to the fourth embodiment. It is a block diagram of a hydraulic circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Rotor core 12 Stator core 13, 13b, 13d Shaft 14 Coil end 15 Permanent magnet 16, 16c, 16d Holding plate 17 Wall which fixes a bearing 18 Cooling oil supply port 20 Cooling oil passage 19, 19b Cooling oil jet 21 , 21b, 21c, 21d Oil passage for cooling oil injected from jet outlet 22 Guide portion 23 Exposed hole of pressing plate 24 Groove portion 27 Bearing 31 Tank 32 Filter 33 Pump 34 Pressure adjustment valve 35 Cooler 36 Transmission 37 Electric motor 101 Magnetic Miscellaneous matter

Claims (9)

In a motor cooling device having a rotor having a permanent magnet extending in the direction of the motor rotation axis and a stator around which a coil is wound,
Supply means for supplying a cooling medium for cooling the electric motor;
A medium path provided with a jet port for injecting the cooling medium toward a permanent magnet extending to an end of the rotor in the motor rotation axis direction;
An electric motor cooling device characterized by comprising:   The medium path is formed in a wall that fixes a bearing of the electric motor, and the ejection port is formed at a position facing a permanent magnet extending at an end portion of the rotor in the motor rotation axis direction. The motor cooling device according to claim 1.   2. The electric motor according to claim 1, wherein the medium path is formed in a direction of an electric motor rotation axis in a rotor shaft of the electric motor, and the ejection port is formed near an end portion of the rotor in an electric motor rotation axis direction. Cooling system.   A part of the permanent magnet is exposed at an end surface in the motor rotation axis direction of the rotor, and the cooling medium sprayed from the ejection port contacts the permanent magnet exposed at an end surface in the motor rotation axis direction of the rotor. The cooling device for an electric motor according to any one of claims 1 to 3. A pressing plate that contacts at least the end surface of the rotor core of the rotor in the direction of the motor rotation axis and presses the rotor from both sides in the direction of the motor rotation axis;
The exposure hole which exposes a part of said permanent magnet to the motor rotating shaft direction end surface of the said rotor is formed in the said pressing plate, The any one of Claims 1-3 characterized by the above-mentioned. Motor cooling system.   At the spout formed in the rotor shaft of the electric motor, a cooling medium that is blown off by centrifugal force when the electric motor rotates is extended to a motor rotating shaft direction end of the rotor, or a motor rotating shaft of the rotor The motor cooling device according to any one of claims 3 to 5, wherein a guide portion that leads to a permanent magnet exposed on a direction end surface is formed. The cross-sectional shape of the motor inner circumferential side of the exposure hole of the pressing plate is a constant angle so as not to prevent the cooling medium injected from the ejection port from coming into contact with the permanent magnet exposed on the end surface of the rotor in the motor rotation axis direction. Have
The cross-sectional shape of the motor outer peripheral side of the exposure hole of the pressing plate has a certain angle so as not to prevent the cooling medium in contact with the permanent magnet from flowing toward the coil end at the motor rotating shaft direction end of the coil. The motor cooling device according to claim 5, wherein the motor cooling device is provided. A pressing plate that contacts at least the end surface of the rotor core of the rotor in the direction of the motor rotation axis and presses the rotor from both sides in the direction of the motor rotation axis;
In the holding plate, there is a groove formed in the rotor shaft of the electric motor in communication with the medium path formed in the electric motor rotating shaft direction via the jet port, and formed in the electric motor inner circumferential direction toward the electric motor outer circumferential direction. Prepared,
5. The motor cooling device according to claim 3, wherein the cooling medium flowing through the groove is in contact with the permanent magnet exposed on the end surface of the rotor in the motor rotation axis direction. 6.   The outlet on the motor outer periphery side of the groove portion formed in the pressing plate has a certain angle so that the cooling medium in contact with the permanent magnet flows toward the coil end of the motor rotating shaft direction end of the coil. The motor cooling device according to claim 8.

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