JP2012210120A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine which prevents a refrigerant from leaking between a rotor core and a retainer and efficiently cools permanent magnets included in a rotor.SOLUTION: In a motor 10, a rotor 30 includes: a rotor shaft 32 in which a refrigerant flows; a rotor core 31 which is fixed to the rotor shaft 32 and includes permanent magnets 36; and a retainer 33 disposed on an end surface of the rotor core 31. The retainer 33 has first radial direction oil passages 41a, 41b formed at the center thereof, when viewed in the thickness direction, so as to extend in the radial direction and communicating with the interior of the rotor shaft 32 and axial oil passages 45 formed in the thickness direction and communicating with the first radial direction oil passages 41a, 41b.

Description

  The present invention relates to a rotating electrical machine including a stator and a rotor. More specifically, the present invention relates to a rotating electrical machine that supplies a refrigerant to a rotor through a refrigerant passage using a retainer and cools a permanent magnet provided in the rotor.

  In general, rotating electrical machines such as induction motors and DC motors (including generators) are widely used as power sources for industrial or vehicle use. In recent years, there has been an increasing demand for motor performance improvement for motors used in hybrid drive vehicles and electric vehicles. Therefore, the stator and the rotor are cooled by a refrigerant such as oil. Here, when the temperature of the permanent magnet provided in the rotor increases, the permanent magnet causes irreversible demagnetization due to heat, and the performance of the motor decreases. Therefore, the permanent magnet is cooled by flowing a refrigerant through the rotor core.

  In a rotating electrical machine that cools a permanent magnet in this way, for example, a groove is provided on one surface (rotor core side surface) of a retainer (end plate), and the retainer is brought into close contact with the rotor core, whereby a coolant passage is formed between the groove and the end surface of the rotor core. The refrigerant flowing through the rotor shaft is supplied to the rotor core through a refrigerant passage formed by the retainer and the rotor core to cool the permanent magnet (see Patent Document 1).

JP 2009-22144 A

  However, in the rotating electric machine described above, since the groove is provided on one surface of the retainer, the rigidity of the front and back of the retainer changes (the rigidity on the side where the groove is provided is reduced), so that the retainer is separated from the rotor core by centrifugal force. It will be deformed away. As a result, a gap is generated between the rotor core and the retainer, and the refrigerant may leak from the gap.

  And if a refrigerant | coolant leaks from between a rotor core and a retainer, the refrigerant | coolant supplied to a rotor core will reduce and the cooling effect of a permanent magnet will fall. In addition, the leaked refrigerant travels through the end face of the rotor core and enters the air gap existing between the rotor and the stator, generating a force that shears the refrigerant when the rotor rotates, resulting in large torque loss (rotor drag loss). ) Occurs and the performance is degraded.

  Accordingly, the present invention has been made to solve the above-described problems, and can prevent the leakage of refrigerant from between the rotor core and the retainer, thereby effectively cooling the permanent magnet provided in the rotor. An object is to provide a rotating electrical machine.

  One aspect of the present invention made to solve the above problems is a rotating electrical machine including a stator including a coil and a rotor rotatably disposed on the inner periphery of the stator, wherein the rotor has a refrigerant therein. A rotor shaft that is fixed to the rotor shaft and includes a permanent magnet; and a retainer disposed on an end surface of the rotor core, the retainer is formed in a radial direction at a center in a thickness direction, and A first radial refrigerant passage that communicates with the interior of the rotor shaft, and an axial refrigerant passage that is formed in the thickness direction and communicates with the first radial refrigerant passage and opens toward the rotor core. To do.

  In this rotating electrical machine, the refrigerant is supplied from the inside of the rotor shaft to the first radial refrigerant passage provided in the retainer. Then, the refrigerant that has flowed into the first radial refrigerant passage is supplied to the rotor core through the axial refrigerant passage. As a result, the permanent magnet is cooled by the refrigerant.

  Here, since the first radial refrigerant passage is formed at the center in the thickness direction of the retainer, the retainer has a substantially symmetrical shape, and the rigidity of the retainer on the front and back is substantially equal. For this reason, the retainer is not deformed by the centrifugal force generated when the rotor rotates. Thereby, since a clearance gap does not arise between a rotor core and a retainer at the time of rotor rotation, the leakage of the refrigerant | coolant from between a rotor core and a retainer can be prevented. As a result, the permanent magnet can be effectively cooled and the drag loss of the rotor can be prevented from occurring.

  In the above-described rotating electrical machine, it is desirable that the axial refrigerant passage communicates with a through hole that penetrates the rotor core in the axial direction.

  With such a configuration, the refrigerant can be allowed to flow into the rotor core while preventing the refrigerant from leaking between the rotor core and the retainer, and thus the cooling effect of the permanent magnet can be enhanced.

  In the rotating electrical machine described above, it is desirable that the axial refrigerant passage includes a protruding portion that protrudes from an end surface of the retainer.

  By adopting such a configuration, since the protruding portion enters the rotor core, it is possible to reliably prevent leakage of the refrigerant from between the rotor core and the retainer. Thereby, a refrigerant | coolant can be reliably supplied to a rotor core inside through a retainer without leaking. Therefore, the cooling effect of the permanent magnet can be further enhanced.

  In the rotary electric machine described above, it is desirable that the retainer has a second radial refrigerant passage formed so as to penetrate in the radial direction at the center in the thickness direction.

  With such a configuration, the refrigerant can be supplied to the root of the coil end (near the end surface of the stator core) of the coil provided in the stator via the second radial refrigerant passage. Thereby, since the part close | similar to the center in the axial direction of a stator can be cooled with a refrigerant | coolant, a stator can be cooled efficiently. Therefore, the permanent magnet can be effectively cooled, and the stator can be effectively cooled.

  In the rotating electrical machine described above, it is desirable that the through hole is a magnet hole that houses a permanent magnet.

  With such a configuration, the permanent magnet can be directly cooled by the refrigerant, so that the cooling effect of the permanent magnet can be further enhanced.

  According to the rotating electrical machine according to the present invention, as described above, leakage of refrigerant from between the rotor core and the retainer can be prevented.

It is sectional drawing which shows schematic structure of the motor which concerns on embodiment. It is a top view of the retainer seen from the end surface side of a rotor core. It is a side view of a retainer. It is sectional drawing in the AA line shown in FIG. 3, and is a figure which shows the positional relationship of a retainer and a magnet hole. It is a figure for demonstrating the positional relationship of the protrusion part (rotation stop) with which a retainer is equipped, and a magnet hole.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a rotating electrical machine according to the present invention will be described in detail with reference to the drawings. Here, a motor mounted on a hybrid vehicle will be described as an example.
Therefore, the motor according to the present embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a schematic configuration of a motor according to the present embodiment. FIG. 2 is a plan view of the retainer as seen from the end face side of the rotor core. FIG. 3 is a side view of the retainer. FIG. 4 is a cross-sectional view taken along line AA shown in FIG. 3, and is also a diagram showing a positional relationship between the retainer and the magnet hole. FIG. 5 is a view for explaining the positional relationship between the protrusion (rotation stop) provided in the retainer and the magnet hole.

  As shown in FIG. 1, the motor 10 includes a stator 20 and a rotor 30. The stator 20 is fixed to the motor case 11, and a rotor 30 is rotatably disposed inside the stator 20. In the present embodiment, the motor case 11 forms a part of a case of a vehicle drive device.

  The stator 20 has a stator core 21 in which a plurality of annular thin electromagnetic steel plates are laminated in the axial direction, and a coil 22 attached to the stator core 21. And the coil 22 protrudes in the axial direction both sides of the stator core 21, and the coil ends 22a and 22b are formed.

  And the rotor 30 is arrange | positioned inside such a stator 20. FIG. The rotor 30 includes a rotor core 31 in which a plurality of annular thin electromagnetic steel plates are laminated in the axial direction, and a rotor shaft 32 fitted in the center of the rotor core 31. Retainers (end plates) 33 and 34 are attached to both ends of the rotor core 31.

  The rotor core 31 is formed with a plurality of magnet holes 35 on the outer peripheral side. Each magnet hole 35 is a hole for accommodating and fixing the permanent magnet 36. These magnet holes 35 are formed such that two adjacent magnet holes 35, 35 are substantially V-shaped in plan view (see FIG. 4). Each magnet hole 35 is formed to penetrate the rotor core 31 in the axial direction. That is, the magnet hole 35 is an example of the “through hole” in the present invention. The rotor core 31 may be provided with a lightening hole formed so as to penetrate the rotor core 31 in order to reduce the weight. Such a hollow hole is also an example of the “through hole” in the present invention.

  Both ends of the rotor shaft 32 are rotatably supported by bearings 12 and 13 held by the motor case 11. The rotor shaft 32 is a hollow shaft, and the hollow portion is an oil passage 38. The oil passage 38 is connected to an oil pump (not shown). Thereby, the oil (refrigerant) stored in the oil pan is supplied to the oil passage 38 by the oil pump. The rotor shaft 32 is formed with a branch oil passage 39 that communicates the oil passage 38 with the outside of the shaft.

  As shown in FIGS. 2 and 3, the retainer 33 has a disk shape, and a through hole 33 a through which the rotor shaft 32 passes is formed at the center thereof. As shown in FIG. 4, a ring-shaped oil reservoir 37 is provided on the outer side of the through hole 33 a (inner peripheral part of the retainer 33). The oil reservoir 37 communicates with the branch oil passage 39 of the rotor shaft 32. As a result, oil is supplied to the oil reservoir 37 from the oil passage 38 of the rotor shaft 32 via the branch oil passage 39, and the oil is temporarily stored in the oil reservoir 37.

  In addition, a plurality of first radial oil passages 41 a and 41 b and a second radial oil passage 42 are provided inside the retainer 33. The first radial oil passages 41 a and 41 b and the second radial oil passage 42 are both formed at the center of the retainer 33 in the thickness direction (axial direction). One ends of the first radial oil passages 41a and 41b and the second radial oil passage 42 communicate with the oil reservoir 37 through communication oil passages 43a, 43b and 44, respectively. The communication oil passages 43a, 43b and 44 are also formed in the center of the retainer 33 in the thickness direction (axial direction). As a result, oil is supplied from the oil reservoir 37 to the first radial oil passages 41a, 41b and the second radial oil passage 42 via the communication oil passages 43a, 43b and 44. The amount of oil supplied to the first radial oil passages 41a, 41b and the second radial oil passage 42 is controlled by adjusting the cross-sectional areas (flow passage areas) of the communication oil passages 43a, 43b and 44. Can be done.

  Since the first radial oil passages 41a and 41b and the second radial oil passage 42 are thus formed at the center of the retainer 33 in the thickness direction, the retainer 33 has a substantially symmetric shape. Thereby, the rigidity of the retainer 33 is substantially equal on the front and back.

  The other ends of the first radial oil passages 41a and 41b communicate with an axial oil passage 45 formed in the thickness direction (axial direction) of the retainer 33 (see FIG. 1). As shown in FIGS. 2 and 3, projecting portions 46 and 47 projecting from the end surface on the rotor core side of the retainer 33 are provided at the other end portion of the axial oil passage 45. In addition, the inside of the protrusions 46 and 47 forms a part of the axial oil passage 45. These protrusions 46 and 47 are arranged in the magnet hole 35 of the rotor core 31 as shown in FIG. Accordingly, the oil supplied to the first radial oil passages 41 a and 41 b is supplied to the magnet hole 35 via the axial oil passage 45. As shown in FIG. 1, the protrusions 46 and 47 enter the rotor core 31, so that oil does not leak between the rotor core 31 and the retainer 33.

  On the other hand, the other end of the second radial oil passage 42 opens to the outer peripheral side surface of the retainer 33 as shown in FIG. Thus, the oil supplied to the second radial oil passage 42 is supplied from the opening on the outer peripheral side surface of the retainer 33 to the root of the coil end 22a (near the end surface of the stator core 21).

  Here, the protrusion 47 has a shape different from that of the protrusion 46, and a flat contact surface 47 a that faces the inner wall surface 35 a of the magnet hole 35 is formed as shown in FIG. 5. Such a protrusion 47 functions as a positioning mechanism for the retainer 33 when the retainer 33 is disposed on the end surface of the rotor core 31. After the disposition, the contact surface 47a abuts against the inner wall surface of the magnet hole 35. The retainer 33 functions as a detent.

  In addition, each protrusion 46 can reduce the rotational unbalance amount of the rotor 30 by adjusting the protrusion amount. Specifically, as shown in FIG. 3, the rotation balance of the rotor 30 may be adjusted by shortening some of the protrusions 46.

  As shown in FIG. 1, a retainer 34 disposed on the opposite side (coil end 22 b side) of the rotor core 31 is formed with a through hole 34 a that penetrates in the thickness direction and communicates with the magnet hole 35. . As a result, when the oil supplied to the magnet hole 35 flows out of the magnet hole 35, it passes through the through hole 34a and is then supplied to the coil end 22b by centrifugal force.

  Next, the operation of the motor 10 described above will be described focusing on the cooling of the permanent magnet 36. The permanent magnet 36 is cooled by preventing the motor 10 from generating irreversible demagnetization due to the eddy current generated in the motor 10 and reducing the torque in the reversible demagnetization region. This is to prevent performance degradation. Further, when a predetermined current flows through the coil 22 attached to the stator core 21, the coil 22 generates heat due to this current, and the resistance value of the coil 22 increases, so that the motor loss is deteriorated. For this reason, in order to prevent the performance degradation of the motor 10, it is necessary to cool the coil 22 (stator 20) as well.

  Therefore, the motor 10 is cooled by supplying oil to the stator 20 and the rotor 30 in the following manner, thereby preventing performance degradation. Specifically, first, the oil supplied to the oil passage 38 formed in the rotor shaft 32 by the oil pump is shifted to the outer peripheral side of the oil passage 38 by the centrifugal force generated by the rotation of the rotor 30. . Then, the oil that has shifted to the outer peripheral side of the oil passage 38 is supplied from the branch oil passage 39 to the oil reservoir 37 of the retainer 33 and temporarily stored therein.

  A part of the oil in the oil reservoir 37 flows into the first radial oil passages 41a, 41b and the second radial oil passage 42 via the communication oil passages 43a, 43b and 44. Then, the oil flowing through the first radial oil passages 41 a and 41 b is supplied to the magnet hole 35 via the axial oil passage 45.

  At this time, the centrifugal force generated by the rotation of the rotor 30 acts on the retainer 33. However, the retainer 33 has a substantially symmetrical shape and the rigidity of the retainer 33 on the front and back is almost equal, so the retainer 33 is not deformed. . Therefore, no gap is generated between the rotor core 31 and the retainer 33. Furthermore, since the protrusions 46 and 47 are provided at the front end of the axial oil passage 45 and these protrusions 46 and 47 are disposed in the magnet hole 35, the oil from between the rotor core 31 and the retainer 33 is removed. Leakage can be reliably prevented. Thereby, oil can be reliably supplied to the inside of the magnet hole 35 through the retainer 33 without leakage. Therefore, since the permanent magnet 36 can be directly cooled with oil, the cooling effect of the permanent magnet 36 can be enhanced. As a result, it is possible to prevent the occurrence of irreversible demagnetization due to the heat of the permanent magnet 36 and the decrease in torque in the reversible demagnetization region. In addition, since oil does not leak from between the rotor core 31 and the retainer 33, oil does not enter between the stator 20 and the rotor 30, so that drag loss of the rotor 30 does not occur.

  On the other hand, the oil flowing through the second radial oil passage 42 is supplied from the opening on the outer peripheral side surface of the retainer 33 to the vicinity of the root of the coil end 22 a (near the end surface of the stator core 21). Thereby, since the part nearer to the center of the stator 20 (coil 22) can be cooled with oil, the stator 20 (coil 22) can be efficiently cooled. As a result, since the heat generation of the coil 22 can be suppressed, an increase in the resistance value of the coil 22 can be prevented, and a decrease in the performance of the motor 10 can be prevented.

  The oil supplied to the vicinity of the root of the coil end 22 a via the second radial oil passage 42 does not enter the air gap existing between the rotor 30 and the stator 20. This is because the oil supplied from the second radial oil passage 42 to the coil end 22 a is supplied in a scattered manner without passing through the end face of the rotor core 31.

  And the oil which passed the magnet hole 35 is discharged | emitted out of the rotor core 31 through the through-hole 34a of the retainer 34 from the opposite end surface of the rotor core 31. FIG. The oil discharged to the outside of the rotor core 31 is blown toward the outer periphery by centrifugal force and supplied to the coil end 22b. Thereby, the coil 22 can be cooled also from the coil end 22b side. Therefore, the coil 22 can be efficiently cooled.

  As described above, according to the motor 10 according to the present embodiment, the oil flowing in the rotor shaft 32 causes the first radial oil passages 41a and 41b and the axial oil passage 45 provided in the retainer 33 to flow. Is supplied to the magnet hole 35 of the rotor core 31. Thereby, the permanent magnet 36 can be cooled directly with oil. Since the first radial oil passages 41a and 41b are formed in the center of the retainer 33 in the thickness direction, the retainer 33 has a substantially symmetrical shape and the rigidity of the retainer 33 on the front and back is substantially equal. The retainer 33 is not deformed by the centrifugal force generated sometimes. Accordingly, no gap is generated between the rotor core 31 and the retainer 33 when the rotor 30 is rotated, so that oil leakage between the rotor core 31 and the retainer 33 can be prevented. Thereby, the permanent magnet 36 can be cooled effectively, and the drag loss of the rotor 30 does not occur.

  It should be noted that the above-described embodiment is merely an example and does not limit the present invention in any way, and various improvements and modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the first radial oil passages 41a and 41b and the second radial oil passage 42 are linearly formed in the radial direction, but these radial oil passages are linearly formed. For example, in order to avoid a hollow hole or the like, it may be formed to be curved or the like so as not to inhibit the flow of oil.

  In the above-described embodiment, the example in which the rotating electrical machine of the present invention is applied to the motor mounted on the drive device of the hybrid vehicle has been described. However, the present invention is not limited to the motor in the drive device, and the permanent magnet is cooled. The present invention can also be applied to motors for various purposes that are required to be, or generators such as generators and alternators.

  Furthermore, although oil (cooling oil) has been exemplified as the refrigerant in the above-described embodiment, a cooling medium other than oil that can ensure insulation can be used.

DESCRIPTION OF SYMBOLS 10 Motor 20 Stator 21 Stator core 22 Coil 30 Rotor 31 Rotor core 32 Rotor shaft 33 Retainer 35 Magnet hole 36 Permanent magnet 38 Oil path 39 Branch oil path 41a First radial oil path 41b First radial oil path 42 Second radial oil Path 45 Axial oil path 46 Projection 47 Projection (rotation stop)

Claims (5)

In a rotating electrical machine including a stator including a coil and a rotor rotatably disposed on the inner periphery of the stator,
The rotor is
A rotor shaft through which refrigerant flows,
A rotor core fixed to the rotor shaft and provided with a permanent magnet;
A retainer disposed on an end surface of the rotor core;
The retainer is
A first radial refrigerant passage formed radially in the thickness direction center and communicating with the interior of the rotor shaft;
An electric rotating machine comprising: an axial refrigerant passage formed in a thickness direction and communicating with the first radial refrigerant passage. In the rotating electrical machine according to claim 1,
The rotary electric machine according to claim 1, wherein the axial refrigerant passage communicates with a through-hole penetrating the rotor core in the axial direction. In the rotating electrical machine according to claim 1 or 2,
The rotating electrical machine according to claim 1, wherein the axial refrigerant passage includes a protruding portion protruding from an end surface of the retainer. In any one rotary electric machine given in Claims 1-3,
The said retainer has a 2nd radial direction refrigerant path formed so that it might penetrate to radial direction in the center of thickness direction, The rotary electric machine characterized by the above-mentioned. In the rotating electrical machine according to claim 2,
The rotating electrical machine according to claim 1, wherein the through hole is a magnet hole for accommodating a permanent magnet.

Images