Cooling structure for dynamo-electric machine

A cooling structure is provided for a dynamo-electric machine. The cooling structure has a refrigerant supply path for introducing a refrigerant into a rotor, and refrigerant outlets that are opened to the refrigerant supply path so that the refrigerant will be splashed onto the coil ends of a stator as the rotor rotates. Blocking wall members are provided in refrigerant splash paths between the refrigerant outlets and the coil ends for blocking a portion of the refrigerant, which splashes from the refrigerant outlets when the rotor rotates. The rate at which the blocking wall members shield the coil ends against the refrigerant is low when the rotor rotates at a low speed and is high when the rotor rotates at a high speed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National stage application of International Application No. PCT/JP2016/067046, filed Jun. 8, 2016, which claims priority to Japanese Patent Application No. 2015-149033, filed in Japan on Jul. 28, 2015. The disclosure of Japanese Patent Application No. 2015-149033 is entirely incorporated herein by reference.

BACKGROUND

Field of the Invention

The present invention relates to a cooling structure for a dynamo-electric machine that cools a dynamo-electric machine using a refrigerant.

Background Information

Conventionally, in order to develop a compact, high-output motor, a structure to efficiently cool parts that reach a high temperature by introducing a refrigerant inside the motor has been studied.

As such a cooling structure, a cooling structure for a dynamo-electric machine is known in which the refrigerant flow path is switched according to the operating state of the motor by incorporating a refrigerant flow path switching part, configured using a spring, a plate, and the like, in a permanent magnet type motor (for example, see Japanese Laid Open Patent Application No. 2009-118686 hereinafter referred to as Patent Document 1). In this prior art, efficient cooling can be realized by supplying refrigerant to a coil during low-speed rotation at which the coil temperature of the stator becomes high, and by supplying refrigerant in a rotor during high-speed rotation at which the magnet temperature of the rotor becomes high.

SUMMARY

However, in the prior art described above, in order to efficiently cool the motor, it is necessary to incorporate flow path switching parts, such as a spring, a plate, and the like, in the rotor. Consequently, there is the problem that the number of parts is increased, and the assembling steps are increased, leading to an increase in cost. In view of the problems described above, an object of the present invention is to provide a cooling structure for a dynamo-electric machine, capable of inexpensively and efficiently cooling a motor.

The cooling structure for a dynamo-electric machine of the present invention comprises a refrigerant outlet that is opened to a refrigerant supply path, such that the refrigerant splashes toward the coil end of the stator as the rotor is rotated. The present invention is configured as a cooling structure for a dynamo-electric machine, in which the rate at which a blocking wall, provided in a refrigerant splash path between the refrigerant outlet and the coil ends, which shields the coil ends against the refrigerant, is low during low-speed rotation and high during high-speed rotation of the rotor.

In the present invention, the rate at which a refrigerant, which splashes in the refrigerant splash path from the refrigerant outlet toward the coil end due to centrifugal force, is supplied to the coil end and the rotor core can be changed according to the rotational speed of the rotor, using a blocking wall provided between the refrigerant outlet of the rotor and the coil end of the stator. Therefore, it is possible to provide a cooling structure for a dynamo-electric machine that is capable of inexpensively and efficiently cooling a motor.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments for realizing the cooling structure for a dynamo-electric machine of the present invention are described below based on the embodiments illustrated in the drawings.

First Embodiment 1

The configuration of the cooling structure for a dynamo-electric machine according to the first embodiment will be described. First, the structure of a dynamo-electric machine A provided with the cooling structure for a dynamo-electric machine according to the first embodiment will be described.FIG. 1is a cross-sectional view illustrating the dynamo-electric machine A. This dynamo-electric machine A comprises a housing1, a rotor2, and a stator3.

The housing1comprises a housing main body11having a substantially cylindrical shape, and a pair of covers12,13having substantially disk shapes, which close openings on both axial ends of this housing main body11, forming a housing space14inside.

The rotor2comprises a rotor shaft21and a rotor core22. The rotor shaft21is disposed along the center axis of the housing1, and both ends thereof are rotatably supported to the covers12,13via a pair of axle bearings25,26. The covers12,13comprise a pair of annular protrusions12a,13a,which protrude in an annular shape in the axial direction toward the housing space14, and the outer perimeters of the axle bearings25,26are supported by the inner perimeters of these annular protrusions12a,13a.

The rotor core22is fixed to the outer perimeter of the rotor shaft21in a state in which a plurality of metal plates are layered in the axial direction, and the two end portions thereof in the axial direction are supported by a pair of end plates22e,22e.The dynamo-electric machine A of the first embodiment is a permanent magnet type synchronous motor, and the rotor core22comprises therein a plurality of permanent magnets22aspaced apart in the circumferential direction.

The stator3comprises a stator core31. This stator core31is disposed via an air gap from the outer perimeter of the rotor core22, and is fixed to the inner perimeter of the housing main body11. In addition, the stator core31comprises a plurality of teeth on the inner perimeter thereof, a coil32is wound around each tooth, and coil ends32eare disposed on the outer sides of the two axial ends of the stator core31. The stator core31is configured by layering a large number of ring-shaped steel plates in the axial direction of the rotor shaft21.

The dynamo-electric machine A configured as described above is capable of functioning as an electric motor by energizing the coil32, as well as functioning as a generator that generates electric power using the driving force that is transmitted from the outside to the dynamo-electric machine A.

Next, the cooling structure in the dynamo-electric machine A will be described. The rotor2is provided with a refrigerant supply path4for supplying refrigerant liquid from the outside of the dynamo-electric machine A. That is, the dynamo-electric machine A is a structure for cooling the permanent magnet22aand the coil end32e.Cooling oil can be used as the refrigerant liquid, but no limitation is imposed thereby.

In addition, the refrigerant liquid is supplied and discharged with respect to the dynamo-electric machine A using a pump, which is not shown.

The refrigerant supply path4comprises a rotational axis flow path41, a radial flow path42, and a rotor axial flow path43. The rotational axis flow path41extends in the axial direction along the center axis of the rotor shaft21from a refrigerant inlet41aat one end of the rotor shaft21, and the distal end thereof in the extending direction is disposed substantially in the central position of the rotor core22in the axial direction.

The radial flow path42extends radially outward from the distal end of the rotational axis flow path41, through the rotor shaft21, to a radially intermediate position of the rotor core22, and a plurality thereof are formed spaced apart in the circumferential direction. The rotor axial flow path43extends from the radially outward distal end of each radial flow path42, and extends along the axial direction to the two axial side end surfaces22b,22bof the rotor core22, and opens refrigerant outlets43aat the two axial end surfaces22b,22bof the rotor core22. The refrigerant outlets43aare provided at substantially equal intervals in the circumferential direction at the two axial side end surfaces22b,22bof the rotor core22, as illustrated inFIG. 2.

When the rotor2is rotated, the refrigerant liquid supplied to the refrigerant supply path4from the refrigerant inlet41aillustrated inFIG. 1is splashed from the refrigerant outlets43atoward the coil ends32ein the outer diameter direction. In the housing space14, the portions where the refrigerant liquid is splashed from the refrigerant outlets43ato the coil ends32ein this manner are the refrigerant splash paths14a.That is, a refrigerant splash path14ais the space sandwiched between the two side end surfaces22b,22bof the rotor core22and the annular protrusions12a,13aof the covers12,13in the direction along the axial direction, and between a refrigerant outlet43aand a coil end32ein the radial direction.

The refrigerant liquid that is splashed through this refrigerant splash path14afalls inside the housing space14, is returned to an oil tank, which is not shown, through discharge holes11c,11cformed in the housing main body11, subjected to heat dissipation using a radiator, or the like, which is not shown, and is returned to the refrigerant supply path4from the refrigerant inlet41a.

Furthermore, the cooling structure of the first embodiment is provided with a blocking wall member5that shields a part of the refrigerant liquid that splashes radially outward from the refrigerant outlets43atoward the coil ends32ein the refrigerant splash path14a.In the first embodiment, the blocking wall member5is fixed to the covers12,13. This blocking wall member5is formed in an annular shape in the portion on the farther side from the side end surface22b,as illustrated inFIG. 2, and shields the refrigerant splash path14aacross the entire circumference.

On the other hand, on the side closer to the side end surface22b,the blocking wall member5forms communication passages51that connect the refrigerant outlet43aside and the coil end32eside, as illustrated inFIG. 1. That is, the communication passages51are formed by the gap between the axial end surface of the blocking wall member5on the rotor core22side and the side end surface22bof the rotor core22, and communication recesses51aformed in the blocking wall member5, as illustrated inFIG. 2. The communication recesses51aare provided at the end portion of the blocking wall member5on the rotor core22side, at constant intervals in the circumferential direction, and the blocking wall member5has a convex/concave shape, as illustrated inFIG. 2.

Therefore, the blocking wall member5shields the refrigerant outlets43atoward the outer diameter direction across the entire circumference at a position away from the two side end surfaces22b,22bof the rotor core22in the axial direction, and the shielding area is large and the shielding degree is high with respect to the coil ends32ein the outer diameter direction. On the other hand, at a position near the two side end surfaces22b,22bof the rotor core22in the axial direction, the blocking wall member5comprises communication passages51having large communication cross-sectional areas on the side close to the side end surface22b,and the shielding area is small and the shielding degree is low with respect to the coil ends32ein the outer diameter direction.

Next, the action of the first embodiment will be described. When driving the dynamo-electric machine A, refrigerant is supplied to the refrigerant inlet41aof the refrigerant supply path4. The refrigerant liquid supplied to this refrigerant supply path4splashes from the refrigerant outlets43athrough the refrigerant splash paths14ain the outer diameter direction by the centrifugal force that acts due to rotation of the rotor2. Then, the refrigerant liquid splashed through the refrigerant splash paths14acarries out heat exchange with and cools the permanent magnet22aof the rotor2and the coil32of the stator3, and is then discharged from the discharge holes11c of the housing main body11. The dynamo-electric machine A is cooled by this circulation of the refrigerant liquid.

In the dynamo-electric machine A, the parts that are likely to generate heat change between the permanent magnet22aof the rotor2and the coil32of the stator3, depending on the rotational speed of the rotor2. In general, during low-speed rotation, it is often desirable to obtain a high output torque. In such a case, the current that is caused to flow in the coil32is increased, which increases copper loss, and the coil32is likely to generate heat. On the other hand, during high-speed rotation, the magnetic flux that crosses the permanent magnet22ais replaced more frequently, which increases hysteresis loss and eddy current loss, i.e., iron loss, and the permanent magnet22aenters into a state more likely to generate heat.

Therefore, in the first embodiment, the location to be cooled is switched by changing the supply rate of the coolant between the permanent magnet22aof the rotor2and the coil32of the stator3, based on the shielding characteristics of the blocking wall member5.

The operation of switching the supply rate of the refrigerant liquid to the rotor core22and the coil end32e,depending on the rotational speed of the dynamo-electric machine A described above in the first embodiment, will be described below. During low-speed rotation of the rotor2, the centrifugal force that acts on the refrigerant liquid that splashes from the refrigerant outlets43ais relatively small compared to that during high-speed rotation, and the flow rate of the refrigerant liquid that splashes from the refrigerant outlets43ais also low. In this case, the rate at which the refrigerant liquid that splashes from the refrigerant outlets43apasses a position close to the two side end surfaces22b,22bof the rotor2in the axial direction increases, as indicated by the dotted arrow LOW inFIG. 2, and the rate at which the refrigerant liquid passes a position far from the two side end surfaces22b,22bdecreases, as indicated by the solid arrow HIGH.

Therefore, during low-speed rotation of the rotor2, the proportion of the refrigerant liquid that splashes from the refrigerant outlets43athat is not shielded by the blocking wall member5and that passes through the communication passages51toward the coil ends32eis higher than during high-speed rotation, and the rate that is shielded by the blocking wall member5is lower than during high-speed rotation. Therefore, the coil ends32eare cooled relatively more efficiently than the rotor core22.

Conversely, during high-speed rotation of the rotor2, the centrifugal force that acts on the refrigerant liquid that splashes from the refrigerant outlets43ais relatively high compared to that during low-speed rotation, and the flow rate of the refrigerant liquid that splashes from the refrigerant outlets43ais made to be high. In this case, the rate at which the refrigerant liquid that splashes from the refrigerant outlets43apasses a position close to the two side end surfaces22b,22bof the rotor2in the axial direction decreases, as indicated by the dotted arrow LOW inFIG. 2, and the rate at which the refrigerant liquid passes a position far from the two side end surfaces22b,22bincreases, as indicated by the solid arrow HIGH.

Therefore, during high-speed rotation of the rotor2, the proportion of the refrigerant liquid that splashes from the refrigerant outlets43athat passes through the communication passages51is lower than during low-speed rotation, and the rate that is shielded by the blocking wall member5increases compared to that during low-speed rotation. Therefore, the supply rate to the coil ends32eis reduced, and the supply rate to the rotor core22and the permanent magnet22ais increased. Thereby, the amount of heat received from the coil ends32eis reduced, the temperature of the refrigerant liquid supplied to the rotor core22and the permanent magnet22ais suppressed, and the rotor core22and the permanent magnet22aare efficiently cooled.

In addition, by providing a blocking wall member5, the flow rate of the refrigerant liquid (oil) that flows from the refrigerant outlets43aradially outward when the rotor2is rotated is limited, and the amount of refrigerant liquid on the inner diameter side of the blocking wall member5is increased compared to when a blocking wall member5is not provided. Accordingly, the supply amount of the coolant (oil) to the axle bearings25,26is increased and the lubricating property can be enhanced; in particular, the supply amount is increased during high-speed rotation, and the lubrication property can be further enhanced.

As described above, the heat generating parts of the dynamo-electric machine A can be efficiently cooled by varying the shielding rate of the blocking wall member5of the refrigerant that splashes radially outward from the refrigerant outlets43aaccording to the rotational speed of the rotor2. Such a difference in the supply rate of the refrigerant to the inside and the outside of the blocking wall member5in accordance with the rotational speed of the rotor2can be achieved using a simple structure in which a blocking wall member5is simply provided between the refrigerant outlets43aof the rotor2and the coil ends32eof the stator3. Therefore, it is possible to provide a cooling structure for a dynamo-electric machine that is capable of inexpensively and efficiently cooling a dynamo-electric machine A.

The effects of the first embodiment will be listed below.

1) The cooling structure for a dynamo-electric machine according to the first embodiment comprises

a refrigerant supply path4for introducing refrigerant into a rotor2of a dynamo-electric machine A, and

refrigerant outlets43athat are opened to the refrigerant supply path4such that the refrigerant splashes toward coil ends32eof a stator3as the rotor2is rotated,

wherein

a blocking wall member5, which shields a part of the refrigerant that splashes from the refrigerant outlets43awhen the rotor2is rotated, is provided in a refrigerant splash path14abetween the refrigerant outlets43aand the coil ends32e,and

the rate at which the blocking wall member5shields the coil ends32eagainst the refrigerant is low during low-speed rotation and high during high-speed rotation of the rotor2.

Therefore, using a simple and inexpensive configuration in which a blocking wall member5is simply provided, and the shielding rate thereof is changed between during low-speed rotation and during high-speed rotation, it is possible to efficiently cool the coil ends32eduring low-speed rotation of the rotor2, and to efficiently cool the rotor core22during high-speed rotation of the rotor2. Therefore, it is possible to inexpensively and efficiently cool a dynamo-electric machine.

2) In the cooling structure for a dynamo-electric machine according to the first embodiment,

the refrigerant outlets43aare provided on two axial side end surfaces22b,22bof a rotor core22of the rotor2, andthe blocking wall member5is configured such that communication passages51that connect the refrigerant outlet43aside and the coil end32eside are formed in the refrigerant splash path14a,and that the cross-sectional area of the communication passage51is formed larger on the side end surface22bside of the rotor core22than on the side far from the side end surface22bof the rotor core22.

Therefore, the action and effect of 1) described above can be obtained using a simple configuration in which communication passages51formed to have a larger cross-sectional area on the side end surface22bside of the rotor core22are provided to the blocking wall member5.

3) In the cooling structure for a dynamo-electric machine according to the first embodiment,

a blocking wall is formed from covers12,13in a housing1of a dynamo-electric machine A forming the side surfaces of the refrigerant splash path14aand a blocking wall member5that is a separate body from the rotor core22.

Therefore, compared to a case in which the blocking wall is integrally formed with one of the housing1and the rotor core22, manufacture is made easy, and setting of the cross-sectional area of the communication passages51and the shielding area in the refrigerant splash path14ais made easy.

Other Embodiments

Next, the cooling structure for a dynamo-electric machine of other embodiments will be described. Since the other embodiments are modified examples of the first embodiment, configurations shared with the first embodiment are given the same reference symbols as the first embodiment and the descriptions thereof are omitted, while describing only the differences from the first embodiment.

Second Embodiment

The cooling structure for a dynamo-electric machine according to the second embodiment will be described.FIG. 3is a perspective view illustrating a rotor2and a blocking wall member205of the cooling structure for a dynamo-electric machine according to the second embodiment, and, as shown, the shape of the blocking wall member205is different from the shape of the blocking wall member5according to the first embodiment.

That is, the blocking wall member205is formed in an annular shape across the entire circumference. In addition, the blocking wall member205comprises, as communication passages, a plurality of first communication holes205aand second communication holes205b,which are formed extending through the blocking wall member205and are respectively disposed at constant intervals in the circumferential direction.

Furthermore, the first communication holes205aare disposed on the side close to the side end surface22bof the rotor core22with respect to the second communication holes205band are formed to have a longer shape in the circumferential direction than the second communication holes205b.As a result, the blocking wall member205is configured such that the cross-sectional area of the communication passages251, which connect the refrigerant outlet43aside and the coil end32eside, is formed larger on the side close to the end surface22bof the rotor core22than on the far side.

Therefore, during low-speed rotation of the rotor2, the proportion of the refrigerant liquid that splashes from the refrigerant outlets43athat passes through the first and second communication holes205a,205bas indicated by the dotted arrow LOW and heads toward the coil ends32eis made to be higher than during high-speed rotation, and the coil ends32ecan be efficiently cooled.

On the other hand, during high-speed rotation of the rotor2, the proportion of the refrigerant liquid that splashes from the refrigerant outlets43athat is shielded by the blocking wall member205as indicated by the solid arrow HIGH inFIG. 3is made to be higher than during low-speed rotation, and the rotor core22and the permanent magnet22acan be efficiently cooled. Therefore, the same effects as 1)-3) described above can be obtained, even with the cooling structure for a dynamo-electric machine according to the second embodiment.

Third Embodiment

The cooling structure for a dynamo-electric machine according to the third embodiment will be described.FIG. 4is a perspective view illustrating a rotor2and a blocking wall member305of the cooling structure for a dynamo-electric machine according to the third embodiment, and, as shown, the shape of the blocking wall member305is different from the shape of the blocking wall member5according to the first embodiment. This blocking wall member305is formed in an annular shape across the entire circumference. Then, a communication passage351that allows refrigerant liquid to flow through is formed between a distal end surface of the blocking wall member305in the direction along the axial direction of the rotor shaft21and the side end surface22bof the rotor core22that is opposed thereto.

Therefore, during low-speed rotation of the rotor2, the proportion of the refrigerant liquid that splashes from the refrigerant outlets43athat passes through the communication passage351between the side end surface22bof the rotor2and the distal end surface of the blocking wall member305becomes higher than during high-speed rotation, as indicated by the dotted arrow LOW inFIG. 4.

Therefore, of the refrigerant liquid that splashes from the refrigerant outlets43a,the supply rate to the coil ends32eincreases, and the coil ends32ecan be efficiently cooled.

On the other hand, during high-speed rotation of the rotor2, the proportion that passes through a position away from the rotor2in the axial direction increases, and the rate that is shielded by the blocking wall member305is increased, as indicated by the solid arrow HIGH inFIG. 4. Accordingly, of the refrigerant liquid that splashes from the refrigerant outlets43a,the proportion of the flow rate that passes through the blocking wall member305and flows toward the outer diameter direction decreases compared to during low-speed rotation, and the rate that is supplied to the rotor core22is increased, thereby efficiently cooling the rotor core22and the permanent magnet22a.Therefore, the same effects as 1)-3) described above can be obtained, even with the cooling structure for a dynamo-electric machine according to the third embodiment.

Fourth Embodiment

The cooling structure for a dynamo-electric machine according to the fourth embodiment will be described.FIG. 5is a cross-sectional view of a dynamo-electric machine provided with the cooling structure for a dynamo-electric machine according to the fourth embodiment, and, as shown, the shape of the blocking wall member405is different from the shape of the blocking wall member5according to the first embodiment.

The blocking wall member405comprises a base plate405aand an annular wall portion405b.The base plate405ais formed in a disk shape, and is fixed to the distal end surfaces of the annular protrusions12a,13aof the covers12,13. The annular wall portion405bis formed in an annular shape, and is integrally joined to the outer perimeter portion of the base plate405a.The shape of this annular wall portion405bmay be any of the shapes of the blocking wall members5,205,305illustrated in the first to the third embodiments. Therefore, in addition to the effects of the first to the third embodiments described above, the fourth embodiment exerts the effect that the supporting strength of the blocking wall member405in the covers12,13can be improved.

Fifth Embodiment

The cooling structure for a dynamo-electric machine according to the fifth embodiment will be described. The fifth embodiment is an example in which the blocking wall is integrally formed with the housing1.FIG. 6is a cross-sectional view of a dynamo-electric machine provided with the cooling structure for a dynamo-electric machine according to the fifth embodiment, and annular protrusions512a,513aof covers512,513, which constitute the housing1, are used as blocking walls.

That is, the distal end surfaces512b,513bof the annular protrusions512a,513aare arranged closer to the two side end surfaces22b,22bof the rotor2, compared to the first embodiment. Then, the refrigerant splash path14apositioned between the two is used as a communication passage551that connects the refrigerant outlet43aside and the coil end32eside.

Therefore, during low-speed rotation of the rotor2, the refrigerant liquid that splashes from the refrigerant outlets43apasses a position near the distal end surfaces512b,513bof the annular protrusions512a,513aas indicated by the arrow LOW, in the same manner as in the first embodiment. Accordingly, of the refrigerant liquid that splashes from the refrigerant outlets43a,the proportion thereof that passes through the communication passage551and heads toward the coil ends32eis high, as indicated by the dotted arrow LOW, and the proportion that heads from the refrigerant outlets43atoward the distal end surfaces512b,513bin an oblique axial direction is low, as indicated by the solid arrow HIGH. Accordingly, during low-speed rotation of the rotor2, the coil ends32eare more efficiently cooled than the rotor2.

On the other hand, during high-speed rotation of the rotor2, the proportion that passes through the communication passage551and heads toward the coil ends32eis low, as indicated by the dotted arrow LOW, and the proportion that heads from the refrigerant outlets43atoward the distal end surfaces512b,513bin an oblique axial direction is high, as indicated by the arrow HIGH. Of the refrigerant liquid that splashes from the refrigerant outlets43a,the rate thereof that is shielded by the annular protrusions512a,513aas indicated by the solid arrow HIGH and heads in the inner diameter direction is increased. Accordingly, during high-speed rotation of the rotor2, the rotor core22and the permanent magnet22aare more efficiently cooled than the coil ends32e.

Furthermore, in the cooling structure for a dynamo-electric machine according to the fifth embodiment, the blocking wall is integrally formed with the annular protrusions512a,513aof the covers512,513, which constitute the housing1of the dynamo-electric machine, forming the side surface of the refrigerant splash path14a. Since an independent blocking wall member is not used as the blocking wall, it is possible to reduce the number of parts and to achieve a reduction in cost.

Sixth Embodiment

The cooling structure for a dynamo-electric machine according to the sixth embodiment will be described.FIG. 7is a cross-sectional view of a dynamo-electric machine to which is applied the cooling structure for a dynamo-electric machine according to the sixth embodiment, and this sixth embodiment is an example in which a blocking wall member605is provided to the rotor2. This blocking wall member605comprises a base plate605aand an annular wall portion605b.The base plate605ais formed in a disc shape, and is provided to both axial ends of the rotor core22, also serving as an end plate.

The annular wall portion605bhas an annular shape, is integrally joined along the outer peripheral edge portion of the base plate605a,and is disposed proximate to the annular protrusions12a,13aof the covers12,13such that the distal end surface thereof shields the space between the refrigerant outlets43aand the coil ends32e.Furthermore, in the annular wall portion605bare formed communication passages651that connect the refrigerant outlet43aside and the coil end32eside in the refrigerant splash path14a,by holes formed at a constant interval in the circumferential direction, in the same manner as the first and second communication holes205a,205bshown in the second embodiment.

Therefore, also in this sixth embodiment, during low-speed rotation of the rotor2, the proportion of the refrigerant liquid that splashes from the refrigerant outlets43athat passes through the communication passages651and heads toward the coil ends32eas indicated by the dotted arrow LOW is made to be high. On the other hand, during high-speed rotation of the rotor2, the proportion of the refrigerant liquid that splashes from the refrigerant outlets43athat is shielded by the annular wall portion605bas indicated by the solid arrow HIGH and heads toward the inner diameter direction is made to be high.

Therefore, the effects of 1)-3) described above can also be obtained using this sixth embodiment. Furthermore, in the sixth embodiment, since the base plate605aof the blocking wall member605also serves as the end plate of the rotor core22, it is possible to reduce the number of parts.

Seventh Embodiment

The cooling structure for a dynamo-electric machine according to the seventh embodiment will be described.FIG. 8is a cross-sectional view of a dynamo-electric machine to which is applied the cooling structure for a dynamo-electric machine according to the seventh embodiment. In this seventh embodiment, the structure of the dynamo-electric machine to which is applied the cooling structure for a dynamo-electric machine is different from the first embodiment, and a so-called winding field type dynamo-electric machine is used. That is, the rotor core722of the rotor702comprises a plurality of slots, which are not shown, on the outer perimeter side in the radial direction at equal intervals in the circumferential direction, and coils727disposed in the slots are wound around the rotor core722; the magnetic poles of the rotor702are excited by energizing the coils727. Coil ends727eare disposed in the edge portions of the two side end surfaces of the rotor core722in the outer diameter direction.

The blocking wall member705is formed in an annular shape, in the same manner as in the third embodiment, and a communication passage751is formed between the distal end surface of the blocking wall member705, and the side end surface722bof the rotor core722including the coil end727efacing the distal end surface of the blocking wall member.

Therefore, also in this seventh embodiment, during low-speed rotation of the rotor2, the proportion of the refrigerant liquid that splashes from the refrigerant outlets43athat passes through the communication passage751and heads toward the coil ends32eas indicated by the dotted arrow LOW is made to be high. On the other hand, during high-speed rotation of the rotor2, the proportion of the refrigerant liquid that splashes from the refrigerant outlets43athat is shielded by the blocking wall member705as indicated by the solid arrow HIGH and heads toward the inner diameter direction is made to be high. Therefore, the effects of 1)-3) described above can also be obtained using this seventh embodiment.

Eighth Embodiment

The cooling structure for a dynamo-electric machine according to the eighth embodiment will be described.FIG. 9is a cross-sectional view of a dynamo-electric machine to which is applied the cooling structure for a dynamo-electric machine according to the eighth embodiment, and this eighth embodiment is an example in which a so-called induction type dynamo-electric machine is used. That is, a rotor core822of a rotor802comprises a plurality of conductor bars827on the outer perimeter portion in the radial direction at equal intervals in the circumferential direction, and an induction current is generated in the rotor802by the rotating magnetic field formed using the stator3to thereby generate a rotational torque.

The blocking wall member805is formed in an annular shape, in the same manner as in the third embodiment, and a communication passage851is formed between the distal end surface of the blocking wall member805and the side end surface822bof the rotor core822including the conductor bar827facing the distal end surface of the blocking wall member. Therefore, the same effects as 1)-3) described above can also be obtained by using an induction type dynamo-electric machine, in the cooling structure for a dynamo-electric machine according to the eighth embodiment.

Ninth Embodiment

The cooling structure for a dynamo-electric machine according to the ninth embodiment will be described.FIG. 10is a cross-sectional view of a dynamo-electric machine to which is applied the cooling structure for a dynamo-electric machine according to the ninth embodiment. This ninth embodiment is different from the first embodiment in the structures of the refrigerant supply path904and the blocking wall member905. That is, the refrigerant supply path904comprises an axial flow path940and outlet holes941. The axial flow path940is formed in the axial center position of the rotor shaft921, across the entire length in the axial direction. In addition, the outlet holes941are formed extending through the rotor shaft921in a position between the annular protrusions12a,13aof the covers12,13and the two side end surfaces22b,22bof the rotor core22in the axial direction, and connect the axial flow path940and the housing space14. Refrigerant outlets941aare thereby formed on the outer perimeter surface of the rotor shaft921.

In addition, the dynamo-electric machine comprises a blocking wall member905between the refrigerant outlets941aand the coil ends32e.This blocking wall member905is formed in an annular shape, and is fixed to the annular protrusions12a,13aof the covers12,13. Furthermore, the blocking wall member905is provided with communication passages951in a position opposing the refrigerant outlets941a.That is, the communication passages951are configured by forming a plurality of holes spaced apart in the circumferential direction, extending through the blocking wall member905in the radial direction, in the same manner as in the second embodiment.

Therefore, the blocking wall member905is configured such that the cross-sectional area of the communication passages951, which connect the refrigerant outlet941aside and the coil end32eside in the refrigerant splash path14a,is formed large on the front position side of the refrigerant outlet941ain the outer diameter direction, and formed small on the side away from this position in the axial direction.

Next, the action of the ninth embodiment will be described. In the ninth embodiment, when the rotor2is rotated, the refrigerant liquid that is supplied to the axial flow path940splashes in the outer diameter direction from the refrigerant outlets941a.At the time of this splashing, some refrigerant splashes straight in the outer diameter direction, as indicated by the dotted arrow LOW, and some refrigerant splashes obliquely toward the annular protrusions12a,13aof the covers12,13and the two side end surfaces22b,22bof the rotor core22, as indicated by the solid arrow HIGH.

During low-speed rotation of the rotor2, the proportion of the refrigerant that splashes straight in the outer diameter direction from the refrigerant outlets941a,as indicated by the dotted arrow LOW, is high; accordingly, the proportion of the refrigerant that passes the communication passages951of the blocking wall member905is high, and the coil ends32eare efficiently cooled.

On the other hand, during high-speed rotation of the rotor2, centrifugal force acts more strongly, and the proportion of the refrigerant that splashes obliquely, as indicated by the solid arrow HIGH, increases; therefore, the rate of the refrigerant shielded by the blocking wall member905is increased. Accordingly, the supply rate of the refrigerant to the coil ends32eis reduced, and the supply rate to the rotor core22and the permanent magnet22ais increased. Thereby, the amount of heat received from the coil ends32eis reduced, the temperature of the refrigerant liquid supplied to the rotor core22and the permanent magnet22ais suppressed, and the rotor core22and the permanent magnet22aare efficiently cooled.

In addition, by providing a blocking wall member905, the flow rate of the refrigerant liquid (oil) that flows from the refrigerant outlets941aradially outward when the rotor2is rotated is limited, and the amount of refrigerant liquid on the inner diameter side of the blocking wall member905is increased compared to when a blocking wall member905is not provided. Accordingly, the supply amount of the coolant (oil) to the axle bearings25,26is increased and the lubricating property can be enhanced; in particular, the supply amount is increased during high-speed rotation, and the lubrication property can be further enhanced.

As described above, in the cooling structure for a dynamo-electric machine according to the ninth embodiment, refrigerant outlets941aare provided on an outer perimeter surface of a rotor shaft921that rotatably supports a rotor core22, and the blocking wall member905is configured such that communication passages951that connect the refrigerant outlet941aside and the coil end32eside are formed in the refrigerant splash path14a,and that the cross-sectional area of the communication passages951is formed larger on a front position side of the refrigerant outlet941ain the outer diameter direction than on the side away from the front position side in the axial direction.

Therefore, during low-speed rotation of the rotor2, the proportion of the refrigerant liquid that passes through the communication passages951of the blocking wall member905is high, and the coil ends32eare efficiently cooled. On the other hand, during high-speed rotation of the rotor2, the rate of the refrigerant liquid that is shielded by the blocking wall member905is made to be high, and the rotor core22and the permanent magnet22aare efficiently cooled. In addition, in the ninth embodiment, it is possible to obtain the action and effects described above using a simple configuration provided with a blocking wall member905having communication passages951, manufacture is made easy, and setting of the cross-sectional area of the communication passages951and the shielding area in the refrigerant splash path14ais made easy.

Tenth Embodiment

The cooling structure for a dynamo-electric machine according to the tenth embodiment will be described.FIG. 11is a cross-sectional view of a dynamo-electric machine to which is applied the cooling structure for a dynamo-electric machine according to the tenth embodiment. This tenth embodiment is a modified example of the ninth embodiment, and is an example in which a so-called induction type dynamo-electric machine is used. That is, a rotor core122of a rotor102comprises a plurality of conductor bars827on the outer perimeter portion in the radial direction at equal intervals in the circumferential direction, and an induction current is generated in the rotor102by the rotating magnetic field formed using the stator3to thereby generate a rotational torque. Therefore, in the tenth embodiment, the same action and effects as in the ninth embodiment can be obtained in an induction type dynamo-electric machine.

Eleventh Embodiment

The cooling structure for a dynamo-electric machine according to the eleventh embodiment will be described.FIG. 12is a cross-sectional view of a dynamo-electric machine to which is applied the cooling structure for a dynamo-electric machine according to the eleventh embodiment. In this eleventh embodiment, the winding field type dynamo-electric machine shown in the seventh embodiment is used as the dynamo-electric machine. That is, the rotor core222of the rotor202comprises a plurality of slots, which are not shown, on the outer perimeter side in the radial direction at equal intervals in the circumferential direction, and coils727disposed in the slots are wound around the rotor core722; the magnetic poles of the rotor702are excited by energizing the coils727. Coil ends727eare disposed in the edge portions of the two side end surfaces of the rotor core222in the outer diameter direction.

The blocking wall member115is formed in an annular shape, and a communication passage151is formed between the distal end surface of-the blocking wall member115and the end surface of the rotor core222including the coil end727efacing the distal end surface of the blocking wall member.

Therefore, also in this eleventh embodiment, during low-speed rotation of the rotor2, the proportion of the refrigerant liquid that splashes from the refrigerant outlets43athat passes through the communication passages151and heads toward the coil ends32eas indicated by the dotted arrow LOW is made to be high. On the other hand, during high-speed rotation of the rotor2, the proportion of the refrigerant liquid that splashes from the refrigerant outlets43athat is shielded by the blocking wall member115as indicated by the solid arrow HIGH and heads toward the inner diameter direction is made to be high. Therefore, the same effects as in the ninth embodiment can also be obtained in this eleventh embodiment.

Twelfth Embodiment

The cooling structure for a dynamo-electric machine according to the twelfth embodiment will be described.FIG. 13is a cross-sectional view of a dynamo-electric machine to which is applied the cooling structure for a dynamo-electric machine according to the twelfth embodiment. The twelfth embodiment is different from the first embodiment in the structure of the refrigerant supply path124, and the blocking wall member5and the housing1are the same as in the first embodiment.

The refrigerant supply path124comprises a rotational axis flow path241, a radial flow path242, and a rotor axial flow path243. The rotor axial flow path243is formed extending through the rotor core22across the entire length in the axial direction, in a position on the radially inner side of the permanent magnet22a,in the same manner as in the first embodiment. The difference from the first embodiment is the mode of supplying the refrigerant liquid to the rotor axial flow path243and supplying the refrigerant liquid from the rotor axial flow path243to the housing space14.

That is, refrigerant outlets243a,which supply refrigerant liquid from the rotor axial flow path243to the housing space14, are opened only on an end plate222eon one end in the axial direction (right side in the drawing). The supply of refrigerant liquid to the rotor axial flow path243is carried out from the other end in the axial direction (left side in the drawing).

Since refrigerant liquid is supplied to the end portions of the rotor axial flow path243in this manner, the configurations of the rotational axis flow path241and the radial flow path242are different from the first embodiment. The rotational axis flow path241is formed from the refrigerant inlet241aat one end of the rotor shaft21(left side end portion in the drawing) to the position of the end plate222eof the rotor core22on the side close to the refrigerant inlet241ain the axial direction, along the center axis of the rotor shaft21.

The radial flow path242comprises a first radial flow path242aand a second radial flow path242b.The first radial flow path242ais formed extending through the rotor shaft21in the radial direction, in a position that overlaps with the refrigerant splash path14ain the axial direction.

The second radial flow path242bis formed along the rotor core22, extending through the rotor shaft21, in a position that overlaps with the end plate222ein the axial direction. The portion along the rotor core22is formed by forming a groove on the end surface of the end plate222e.In addition, a plurality of rotor axial flow paths243, first radial flow paths242a,second radial flow paths242b,and refrigerant outlets243aas described above are formed at substantially equal intervals in the circumferential direction.

Next, the action of the twelfth embodiment will be described. When the rotor12R is rotated, the refrigerant liquid, which is supplied to the refrigerant supply path124from the refrigerant inlet241aas illustrated inFIG. 13, is splashed in the outer diameter direction in the refrigerant splash path14aof the housing space14from the first radial flow path242adue to centrifugal force. Additionally, in parallel with the above, the refrigerant liquid that cools the rotor12R via the radial flow path242and the rotor axial flow path243is splashed in the outer diameter direction in the refrigerant splash path14aof the housing space14from the refrigerant outlet243aat one end of the rotor12R.

The action of the refrigerant liquid that splashes from the refrigerant outlet243ais the same as in the first embodiment. That is, during low-speed rotation of the rotor12R, the flow rate of the refrigerant liquid that splashes from the refrigerant outlets243ais low, the proportion thereof that passes through the blocking wall member5toward the coil ends32eis higher than during high-speed rotation, and the rate that is shielded by the blocking wall member5is lower than during high-speed rotation. Therefore, the coil ends32eare cooled relatively more efficiently than the rotor core22.

On the other hand, during high-speed rotation of the rotor12R, the flow rate of the refrigerant liquid that splashes from the refrigerant outlets243ais made to be high, the proportion that passes through the communication passage51decreases compared to during low-speed rotation, the supply rate to the coil ends32edecreases, and the supply rate to the rotor core22and the permanent magnet22aincreases. The rotor core22and the permanent magnet22aare thereby efficiently cooled.

The action of the refrigerant liquid that splashes from the first radial flow path242ais the same as described above; during low-speed rotation of the rotor12R, the flow rate of the refrigerant liquid that splashes from the refrigerant outlet243ais low. Accordingly, the proportion of the refrigerant that passes through the blocking wall member5toward the coil ends32eis higher than during high-speed rotation, and the coil ends32eare cooled relatively more efficiently than the rotor core22.

On the other hand, during high-speed rotation of the rotor12R, the flow rate of the refrigerant liquid that splashes from the refrigerant outlets243ais made to be high, the proportion that passes through the communication passage51decreases compared to during low-speed rotation, the supply rate to the coil ends32edecreases, and the supply rate to the rotor core22and the permanent magnet22aincreases. The rotor core22and the permanent magnet22aare thereby efficiently cooled.

In addition to exerting the effects of 1), 2), and 3) as described above in the first embodiment, the cooling structure for a dynamo-electric machine according to the twelfth embodiment described above exerts the following effects. Since supply of refrigerant liquid to the rotor axial flow path243is carried out from the second radial flow path242bformed in the end plate222e,the laminated steel plates that form the rotor core22may all have the same shape. Therefore, it is possible to reduce the number of parts of the rotor core22, to reduce the trouble of layering steel plates having different shapes in predetermined positions during manufacture, and to thereby reduce cost.

Thirteenth Embodiment

The cooling structure for a dynamo-electric machine according to the thirteenth embodiment will be described.FIG. 14is a cross-sectional view of a dynamo-electric machine to which is applied the cooling structure for a dynamo-electric machine according to the thirteenth embodiment. This thirteenth embodiment is a modified example of the twelfth embodiment, and the refrigerant supply path134comprises a first rotor axial flow path243A and a second rotor axial flow path243B. The two rotor axial flow paths243A,243B have exactly the same structures, but the mode of supplying the refrigerant liquid and the supply from the refrigerant outlets243ato the housing space14are different.

That is, the rotor13R comprises end plates222eprovided with the second radial flow path242bas shown in the twelfth embodiment at both ends in the axial direction. Then, as shown, the first rotor axial flow path243ais connected to the second radial flow path242bas seen at the right side end portion in the drawing, and comprises a refrigerant outlet243aas seen on the left side in the drawing. On the other hand, the second rotor axial flow path243bis connected to the second radial flow path242bat the left side end portion as seen in the drawing, and comprises a refrigerant outlet243aas seen on the left side in the drawing.

Therefore, the rotational axis flow path341is formed from the refrigerant inlet341aat one end of the rotor shaft21(left side end portion as seen in the drawing) to the position of the end plate222eon the side far from the refrigerant inlet341ain the axial direction, along the center axis of the rotor shaft21.

In addition to comprising a first radial flow path242aand a second radial flow path242bin the same manner as the twelfth embodiment, the radial flow path242comprises a second radial flow path242bformed in the end plate222eas shown on the right side in the drawing.

As described above, since the first radial flow path242ais opened to the refrigerant splash path14aon the left side in the drawing, it is preferable that the number of first rotor axial flow paths243A is greater than the number of second rotor axial flow paths243B.

In the cooling structure for a dynamo-electric machine according to the thirteenth embodiment described above, in the same manner as in the twelfth embodiment, when the rotor13R is rotated, the refrigerant liquid, which is supplied to the refrigerant supply path134, is splashed in the outer diameter direction in the refrigerant splash path14aof the housing space14from the first radial flow path242adue to centrifugal force. Additionally, in parallel with the above, the refrigerant liquid that cools the rotor13R via the radial flow path242and the two rotor axial flow paths243A,243B is splashed in the outer diameter direction in the refrigerant splash path14aof the housing space14from the refrigerant outlets243a.

Then, in the same manner as in the twelfth embodiment, during low-speed rotation of the rotor13R, the proportion of the refrigerant that passes through the blocking wall member5from the first radial flow path242aand the refrigerant outlets243atoward the coil ends32eis higher than during high-speed rotation, and the coil ends32eare efficiently cooled.

On the other hand, during high-speed rotation of the rotor13R, the flow rate of the refrigerant liquid that splashes from the first radial flow path242aand the refrigerant outlets243ais made to be high, the proportion that passes through the communication passage51decreases compared to during low-speed rotation, and the rotor core22and the permanent magnet22aare efficiently cooled.

In addition to exerting the effects of 1), 2), and 3) as described above in the first embodiment, in the cooling structure for a dynamo-electric machine according to the thirteenth embodiment as described above, the laminated steel plates that form the rotor core22may all have the same shape, in the same manner as in the twelfth embodiment. Therefore, it is possible to reduce the number of parts of the rotor core22, to reduce the trouble of layering steel plates having different shapes in predetermined positions during manufacture, and to thereby reduce cost.

The embodiments of the cooling structure for a dynamo-electric machine of the present invention are described above, but specific configurations thereof are not limited to these embodiments, and various modifications and additions to the design can be made without departing from the scope of the invention according to each claim in the Claims.

For example, in the embodiments, an example was given in which the blocking wall member is provided to one of the rotor core and the housing, but a blocking wall member may be provided to both the rotor core and the housing, and a communication passage may be formed between the two. In addition, the same shape as the blocking wall member may be integrally formed using one of the housing and the rotor core as the blocking wall. Additionally, when forming communication passages in the blocking wall, the cross-sectional shape thereof is not limited to the shapes shown in the embodiments.