JP2013013182A - Cooling structure for motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling structure for a motor that has high cooling capacity and can suppress a local temperature rise regardless of a length in an axial direction of a stator disposed at an outer peripheral side.SOLUTION: A cooling structure 1 for a motor comprises: a case 2 filled with cooling oil 29; a rotor 3 rotatably pivoted about an axial line AX in the case 2; and a stator 6 that is disposed apart from an axis of the rotor 3 at an outer peripheral side of the rotor 3 and is fixed to the case 2. The rotor 3 includes: an axial direction oil passage 8 that extends in the axial line AX direction and is supplied with the cooling oil 29; and a plurality of radial direction oil passages 9 that branches off from the axial direction oil passage 8 and individually has openings 581 at a plurality of portions spaced apart from one another in the axial line AX direction on an outer peripheral surface of the rotor 3. Further, it is preferable that the rotor 3 be constituted of a shaft 4 and a rotor core 5, the axial direction oil passage 8 be formed with an axial direction groove 45 engraved on an outer peripheral surface of the shaft 4 and the radial direction oil passages 9 be formed with radial direction holes 57 and 58 bored inside the rotor core 5 in a radial direction.

Description

  The present invention relates to a cooling structure for a motor using cooling oil.

  There are various types and structures of motors, and usually the rotor and stator have a core (iron core), and at least one of them has a coil (winding). The core constitutes a magnetic circuit, and no-load loss such as eddy current loss and hysteresis loss occurs inside the core during motor operation. The coil constitutes an electric circuit, and load loss such as resistance loss is generated inside the coil during motor operation. Since the temperature inside the motor rises due to the occurrence of no-load loss and load loss, cooling is required. In general, a motor having a small capacity is naturally cooled by air, and when the capacity exceeds a certain level, cooling using cooling oil sealed in a case is performed. The cooling oil is often used in common with a lubricating oil for lubricating a bearing portion that supports the rotor.

  One technical example of a motor cooling structure using this type of cooling oil is disclosed in Patent Document 1. Claim 1 of Patent Document 1 includes a rotor including a rotor shaft and a core, the rotor shaft has an axial oil passage and a radial oil passage, the core has an axial oil passage, and the shaft of the rotor shaft. A motor cooling circuit provided with supply means for supplying oil to a directional oil passage is disclosed. In this cooling circuit, the cooling oil sequentially flows through the three oil passages to cool the rotor. According to a second aspect of the present invention, the stator further includes a coil end disposed radially outward of the rotor and projecting to both ends in the axial direction, and the diameter of the coil end is disposed on the plates disposed at both axial ends of the rotor core. A configuration in which an oil hole that opens inward is formed. In this configuration, cooling oil is supplied from the rotor-side plate toward the stator-side coil end by the action of centrifugal force, and the stator is also cooled.

JP-A-9-182375

  By the way, in the motor cooling circuit disclosed in Patent Document 1, it is preferable that the cooling oil supplied to the rotor side can be supplied to the stator for cooling, but the cooling oil supply point to the stator side is the coil end 2. Limited to places. For this reason, it is difficult for the cooling oil to reach the axial intermediate portion of the stator, and particularly when the axial length of the stator is long, the cooling performance of the axial intermediate portion becomes insufficient, and an excessive temperature rise occurs locally. Tend to.

  The present invention has been made in view of the above problems of the background art, and has a high cooling capacity and can suppress a local temperature rise regardless of the axial length of the stator disposed on the outer peripheral side. Providing a cooling structure is a problem to be solved.

  The invention of the motor cooling structure according to claim 1 that solves the above-described problem includes a case in which cooling oil is enclosed, a rotor that is rotatably supported around the axis in the case, and coaxially on an outer peripheral side of the rotor. A cooling structure for a motor including a stator that is spaced apart and fixed to the case, wherein the rotor extends in an axial direction and is supplied with the cooling oil, and the shaft A plurality of radial oil passages branched from the directional oil passage and opened at a plurality of locations separated in the axial direction of the outer circumferential surface of the rotor.

  According to a second aspect of the present invention, in the first aspect, the rotor includes a shaft disposed on the axis, and a cylindrical rotor core integrally assembled on an outer periphery of the shaft. The axial oil passage is formed by an axial groove engraved in the axial direction on the outer peripheral surface of the rotor core, the axial oil passage is formed in the rotor core in the radial direction, and the inner side opens to the inner peripheral surface of the core. The radial oil passage is formed by a radial hole that faces the axial groove and opens to the outer peripheral surface of the core, and the stator has a cylindrical stator core having magnetic pole teeth and a slot space on the inner peripheral side, and the slot A coil including a conductor disposed in a space is configured.

  According to a third aspect of the present invention, in the second aspect, the rotor core is configured by stacking a plurality of annular thin rotor core plates in the axial direction, and a part of the rotor core plate opens to the inner peripheral surface of the core. And having a bottomed inner slit hole facing the axial groove of the shaft, and another part of the rotor core plate adjacent to the part of the rotor core plate has a bottomed outer slit hole opened to the outer peripheral surface of the core. The inner slit hole and the outer slit hole communicate with each other inside the rotor core to become the radial hole, and the radial oil passage is formed.

  The invention according to claim 4 is the method according to any one of claims 1 to 3, in accordance with each distance between the supply position of the cooling oil in the axial oil passage and the branch position of the plurality of radial oil passages. The smaller the distance, the smaller the cross-sectional area of the radial oil passage, and the larger the distance, the larger the cross-sectional area of the radial oil passage.

  A fifth aspect of the present invention provides the suction according to any one of the first to fourth aspects, wherein the cooling oil supply position in the axial oil passage communicates with the bottom portion in which the cooling oil stays in the case. An oil passage is further provided, or a pumping oil passage that communicates a supply position of the cooling oil in the axial oil passage with a bottom portion where the cooling oil stays in the case, and in the middle of the pumping oil passage An oil pump is further provided.

  In the invention of the motor cooling structure according to claim 1, the rotor includes an axial oil passage that extends in the axial direction and is supplied with cooling oil, and an axial branch of the rotor outer circumferential surface that branches from the axial oil passage. And a plurality of radial oil passages that open at a plurality of spaced locations. For this reason, when the rotor rotates, the cooling oil supplied to the axial oil passage flows out of the plurality of radial oil passages outward in the radial direction by the action of centrifugal force, jumps out from the opening on the outer peripheral surface of the rotor, and Is supplied to the stator. Therefore, by providing an appropriate number of radial oil passages in the axial direction of the rotor according to the axial length of the stator, a sufficient amount of cooling oil can be supplied to various locations in the axial direction of the stator, and a high cooling capacity The local temperature rise of the stator can be suppressed. The rotor is also cooled well by the cooling oil flowing through the axial oil passage and the plurality of radial oil passages.

  In the invention according to claim 2, the rotor includes a shaft and a rotor core, the axial oil passage is formed by the axial groove on the outer peripheral surface of the shaft, and the radial oil passage is formed by the radial hole of the rotor core. On the other hand, the stator includes a stator core and a coil. Thereby, since the axial direction oil path and radial direction oil path of a rotor can be formed easily, the increase in the cost by the effort of member processing can be suppressed. Moreover, since the coil which is likely to generate a local temperature rise is disposed on the inner peripheral side of the stator and the cooling oil is directly supplied to the plurality of locations, a high cooling capacity can be further ensured.

  In the invention according to claim 3, the rotor core is configured by laminating a plurality of rotor core plates, some of the rotor core plates have inner slit holes, and another adjacent rotor core plate has outer slit holes. And the inner slit hole and the outer slit hole communicate with each other to form a radial oil passage. Since the inner slit hole and the outer slit hole are slits in the middle of the annular rotor core plate in the radial direction, the annular shape of the plate is maintained, and the mechanical strength of the rotor core is easily ensured. Moreover, the workability | operativity of the lamination | stacking operation | work of the plate for manufacturing a rotor core does not fall. If a slit is formed from the inner circumferential surface to the outer circumferential surface of the rotor core plate and the plate is changed from an annular shape to a C-shape, the mechanical strength of the rotor core tends to be lowered, and the workability of the laminating work is lowered. May also occur.

  In the invention according to claim 4, the smaller the distance between the cooling oil supply position in the axial oil passage and the branch position of the radial oil passage, the smaller the cross-sectional area of the radial oil passage, and the larger the distance, the more The cross-sectional area of the radial oil passage is increased. Thereby, the fluid resistance related to each radial oil passage is equalized and the cooling oil is evenly distributed, so that each part in the axial direction of the stator is evenly cooled, and a higher cooling capacity can be secured.

  In the invention which concerns on Claim 5, the suction oil path which connects the supply position of the cooling oil in an axial oil path, and a case bottom part is further provided, or a pumping oil path and an oil pump are further provided. In the present invention, when the rotor having the axial oil passage and the radial oil passage is rotated, it acts as a centrifugal pump, so that a suction pressure is generated. If the suction pressure is greater than the hydraulic pressure difference depending on the height of the cooling oil supply position and the case bottom in the axial oil passage, the cooling oil can automatically reach the axial oil passage by providing a suction oil passage. Sucked up. When the suction pressure is smaller than the hydraulic pressure difference depending on the height, the pumping oil passage and the oil pump are provided, and the cooling oil can be pumped up to the axial oil passage by the pump discharge pressure. As the oil pump, a mechanical oil pump using the rotation of the rotor, an electric oil pump that operates by electricity, or the like is used. In the case where the suction oil passage is provided and the case where the pumping oil passage and the oil pump are provided, the cooling oil can be stably supplied to the axial oil passage with a simple configuration.

It is sectional drawing along the axial direction which shows typically the cooling structure of the motor of 1st Embodiment. It is sectional drawing of the surface orthogonal to the axis line which shows typically the cooling structure of the motor of 1st Embodiment, and is XX direction sectional drawing of FIG. It is a figure explaining the shape of three types of rotor core plates which comprise the rotor core of 1st Embodiment. It is sectional drawing which shows typically the cooling structure of the motor of 2nd Embodiment. It is sectional drawing which shows typically the cooling structure of the motor of 3rd Embodiment. It is a figure explaining the shape of two types of rotor core plates which comprise the rotor core of 3rd Embodiment. It is sectional drawing which shows typically the cooling structure of the motor of 4th Embodiment which deform | transformed the shape of the oil path from 1st Embodiment. It is sectional drawing which shows typically the cooling structure of the motor of 5th Embodiment which deform | transformed the shape of the oil path from 1st Embodiment. It is sectional drawing which shows typically the cooling structure of the motor of 6th Embodiment provided with a pumping oil pipe and a mechanical oil pump. It is sectional drawing which shows typically the cooling structure of the motor of 7th Embodiment provided with a pumping oil pipe | tube and an electric oil pump.

  A motor cooling structure according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view along the axis AX direction schematically showing the motor cooling structure 1 of the first embodiment. 2 is a cross-sectional view of a plane orthogonal to an axis AX schematically showing the motor cooling structure 1 of the first embodiment, and is a cross-sectional view taken along the line XX in FIG. The motor cooling structure 1 includes a case 2, a rotor 3 having an axial oil passage 8 and a plurality of radial oil passages 9, a stator 6 on the outer peripheral side of the rotor 3, a suction oil pipe 71, and the like.

  The case 2 includes a substantially cylindrical case tube portion 21 having an axis AX, two disk-shaped case side portions 22 and 23 that close circular openings on both sides of the case tube portion 21, and a lower side of the case tube portion 21. The gantry 24 is formed integrally. A shaft hole 25 is formed in the center of one case side portion 22, and a bearing portion 26 is disposed around the shaft hole. An annular support seat 27 extending from the case tube portion 21 is disposed at a position entering the inside of the axis AX from the other case side portion 23, and a bearing portion 28 is disposed on the inner peripheral side of the support seat 27. It is installed. A cooling oil 29 is enclosed in the internal space of the case 2. The oil level OL of the cooling oil 29 is lower than the lowermost end of the rotor 3, and a part of the stator 6 is immersed in the cooling oil 29.

  The rotor 3 includes a shaft 4 disposed on the axis AX, and a cylindrical rotor core 5 that is integrally assembled on the outer periphery of the shaft. One end 41 of the shaft 4 is oil-tightly inserted through the central shaft hole 25 of one case side portion 22 of the case 2 and extended to the outside of the case 2, and can be driven to rotate by connecting a load. ing. The end of the shaft 4 near the one end 41 is rotatably supported by a bearing portion 26 of one case side portion 22. The other end 42 of the shaft 4 is rotatably supported by a bearing portion 28 on the inner peripheral side of the support seat 27.

  A shaft supply oil passage 43 extending from the other end 42 to the vicinity of the center in the axial direction AX is formed in the shaft center of the shaft 4. A suction oil pipe 7 to be described later is connected to an opening 431 on the other end 42 side of the shaft supply oil passage 43. Further, two radial supply oil passages 44 extending in the radial direction from the tip 432 near the center of the axial direction AX of the axial center oil passage 43 are formed. The two radial supply oil passages 44 are arranged at axially symmetric positions (vertical direction in FIG. 1) and have an opening 441 on the outer periphery of the shaft 4.

  Two axial grooves 45 are formed on the outer peripheral surface of the shaft 4 in the direction of the axis AX. The two axial grooves 45 are disposed at axially symmetric positions that communicate with the opening 441 of the radial supply oil passage 44. Each axial groove 45 extends to the vicinity of the axial end portion of the rotor core 5 and does not reach the bearing portions 26 and 28. Each axial groove 45 forms an axial oil passage 8 of the present invention that flows cooling oil in the direction of the axis AX. The opening 441 of the radial supply oil passage 44 corresponds to a supply position 81 for supplying cooling oil to the axial oil passage 8.

  The rotor core 5 is configured by laminating a plurality of thin and thin three types of rotor core plates 51 to 53 in the direction of the axis AX. FIG. 3 is a diagram illustrating the shapes of the three types of rotor core plates 51 to 53 constituting the rotor core 5 of the first embodiment. 3A is a shape of a first type rotor core plate 51 having an inner slit hole 57 (hereinafter abbreviated as first plate 51), and FIG. 3B is a second type rotor core plate 52 having an outer slit hole 58. (3) is the shape of the third type rotor core plate 53 (hereinafter abbreviated as the third plate 53) that does not have the slit holes 57 and 58.

  The first to third plates 51 to 53 are formed on the basis of a thin electromagnetic steel plate having a high magnetic permeability and an annular shape having an inner peripheral edge 54 having the same inner diameter and an outer peripheral edge 55 having the same outer diameter. . That is, four elongated rectangular magnetic pole holes 56 are formed in an annular electromagnetic steel sheet in a circumferentially symmetrical manner at a pitch of 90 °, thereby forming the third plate 53 of (3) in FIG. . Further, two inner slit holes 57 are formed at axially symmetric positions outward from the inner peripheral edge 54 of the third plate 53 in the radial direction, thereby forming the first plate 51 of (1) in FIG. . The inner slit hole 57 is disposed between the magnetic pole holes 56, has a constant slit width d from the opening 571 to the bottom 572 of the inner peripheral edge 54, and is formed up to a half of the band width W to the outer peripheral edge 55. Yes.

  Further, two outer slit holes 58 are formed at axially symmetric positions radially inward from the outer peripheral edge 55 of the third plate 53, thereby forming the second plate 52 of (2) in FIG. . The outer slit hole 58 is disposed between the magnetic pole holes 56, and the slit width d from the opening 581 of the outer peripheral edge 55 to the bottom 582 is the same as that of the inner slit hole 57, and is half of the band width W to the inner peripheral edge 54. It is formed until too much. The inner slit hole 57 and the outer slit hole 58 have bottom portions 571 and 572, respectively, and do not penetrate in the radial direction, and the annular shapes of the first and second plates 51 and 52 are maintained.

  Returning to FIG. 1 and FIG. 2, the configuration of the rotor core 5 will be described. The rotor core 5 is configured by sequentially stacking three types of first to third plates 51 to 53 in the direction of the axis AX. More specifically with reference to FIG. 1, the end plate 5 </ b> E <b> 1 is disposed on the outer periphery of the shaft 4 near the one end 41. Then, in order from the one end 41 side of the shaft 4 to the other end 42 side, a plurality of third plates 53 are stacked adjacent to the end plate 5E1, and then the plurality of second plates 52 and a plurality of adjacent plates are sequentially adjacent. A plurality of first plates 51 are stacked. The stacking of the plurality of third, second, and first plates 53, 52, 51 is repeated five times. Finally, a plurality of third plates 53 are stacked near the other end 42, and another end plate 5E2 is disposed.

  In addition, when the thickness for every electromagnetic steel plate used as the basis of the 1st-3rd plates 51-53 has dispersion | variation, the number of lamination | stacking is adjusted suitably and lamination | stacking thickness is adjusted. Between the two end plates 5E1, 5E2, the shape of the rotor core 5 is determined by being firmly bound by a fastening member (not shown). Further, as shown in FIG. 2, the permanent magnet 5M is embedded through the magnetic pole holes 56 of the first to third plates 51 to 53 in the direction of the axis AX.

  As shown in FIG. 1, when the rotor core 5 is configured, the inner slit hole 57 of the first plate 51 and the outer slit hole 58 of the second plate 52 which are adjacent to each other at five locations overlap in the middle in the radial direction. It becomes a radial hole and forms the radial oil passage 9 of the present invention. The inner sides of the five radial oil passages 9, that is, the inner openings 571 of the inner slit holes 57 communicate with the axial grooves of the shaft 5. Further, the outer side of the five radial oil passages, that is, the outer opening 581 of the outer slit hole 58 opens to the outer peripheral surface of the core.

  The stator 6 is coaxially spaced on the outer peripheral side of the rotor 3 and is fixed to the inner peripheral surface of the case cylinder portion 21 of the case 2. The stator 6 includes a stator core 61 and a coil 65. As shown in FIG. 2, the stator core 61 has six magnetic pole teeth 62 protruding toward the inner peripheral side, and a slot space 63 is formed between the magnetic pole teeth 62. A conductor is disposed in the slot space 63 to constitute a coil 65. The coil 65 is a concentrated winding coil that circulates around the magnetic pole teeth 62, but is not limited to this and may be a distributed winding coil. The coil 65 protrudes from the stator core 61 at the end in the axis AX direction to form a coil end portion.

  The suction oil pipe 71 communicates the opening 431 of the axial supply oil passage 43 of the shaft 4 with the bottom where the cooling oil 29 stays in the case 2. The suction oil pipe 7 can be made of a metal pipe material or a resin pipe material. The suction oil pipe 71, the axial supply oil path 43 and the radial supply oil path 44 of the shaft 4 constitute the suction oil path of the present invention. In the present embodiment, when the rotor 3 having the axial oil passage 8 and the radial oil passage 9 rotates, the rotor 3 acts as a centrifugal pump, so that suction pressure is generated. Furthermore, in this embodiment, the rotational speed of the motor is relatively large, and the suction pressure is at the height between the cooling oil supply position 81 (opening 441 of the radial supply oil path 44) and the bottom of the case 2 in the axial oil path 8. It becomes larger than the hydraulic pressure difference. Therefore, the cooling oil 29 can be sucked up to the supply position 81 of the axial oil passage 8 and supplied stably.

  Next, the operation of the motor cooling structure 1 of the first embodiment will be described with reference to arrows F1 to F6 indicating the flow of the cooling oil in FIG. When the rotor 3 rotates, the cooling oil 29 at the bottom of the case 2 is sucked up into the suction oil pipe 7 by the action of the centrifugal pump described above (see arrow F1), and reaches the opening 431 of the shaft supply oil passage 43 of the shaft 4. The cooling oil flows in the axial supply oil passage 43 in the direction of the axis AX (see arrow F2), and flows in the radial supply oil passage 44 radially outward by centrifugal force (see arrow F3). Then, the cooling oil enters the axial oil passage 8 and flows separately on both sides in the axis AX direction (see arrow F4), and branches into each inner slit hole 57 (each radial oil passage 9) of the rotor core 5. Further, the cooling oil flows radially outward through the inner slit hole 57 by centrifugal force (see arrow F5), and flows radially outward across the outer slit hole 58 (see arrow F6). Then, the cooling oil jumps out of the five outer openings 581 aligned in the axis AX direction on the outer peripheral surface of the rotor core.

  The cooling oil that has jumped out is supplied to the stator 3 by pouring down. At this time, since the rotor 3 is rotating, the cooling oil is supplied not only to the magnetic pole teeth 62 but also directly to the coil 65 in the slot space 63.

  According to the motor cooling structure 1 of the first embodiment, an appropriate number of radial oil passages 9 according to the axial length of the stator 6, in this embodiment, five radial oil passages 9 are provided apart in the axis AX direction of the rotor 3. A sufficient amount of cooling oil can be supplied to various locations in the axis AX direction of the stator 6. For this reason, compared with the prior art which supplies cooling oil only to two coil ends, it has a high cooling capacity and can suppress the local temperature rise of the stator 6. In particular, since the coil 65 that is likely to cause a local temperature rise is arranged on the inner peripheral side of the stator 6, the cooling oil can be directly supplied to a plurality of locations of the coil 65, and the high cooling capacity can be further ensured. . The rotor 3 is also cooled well by the cooling oil flowing through the axial oil passage 8 and the plurality of radial oil passages 9.

  Further, the plurality of radial oil passages 9 of the rotor 3 are formed by communicating the inner slit hole 57 of the first plate 51 and the outer slit hole 58 of the second plate 52. Therefore, the annular shape of the first and second plates 51 and 52 is maintained, and the mechanical strength of the rotor core 5 can be easily ensured. Moreover, the workability | operativity of the lamination | stacking operation | work of the 1st-3rd plates 51-53 for manufacturing the rotor core 5 does not fall.

  In addition, the cooling oil can be stably supplied to the axial oil passage 8 by using a very simple configuration of the suction oil pipe 7.

  Next, the motor cooling structure 1A of the second embodiment in which the cross-sectional areas of the plurality of radial oil passages 9 are different will be described mainly with respect to differences from the first embodiment. FIG. 4 is a cross-sectional view schematically showing a motor cooling structure 1A of the second embodiment. In the drawing, the axial groove 45 of the rotor shaft 4 is expressed as an axial oil passage 8A, and the opening 441 of the radial supply oil passage 44 is expressed as a cooling oil supply position 81A in the axial oil passage 8A. Furthermore, each radial hole formed by the inner slit hole 57 and the outer slit hole 58 of the first and second plates 51 and 52 of the rotor core 5A is denoted as five radial oil passages 91 to 95.

  In the second embodiment, according to the distances L1 to L5 between the cooling oil supply position 81A in the axial oil path 8A and the branch positions of the five radial oil paths 91 to 95, the smaller the distances L1 to L5, The sectional areas S1 to S5 of the radial oil passages 91 to 95 are made smaller, and the sectional areas S1 to S5 of the radial oil passages 91 to 95 are made larger as the distances L1 to L5 are larger. Specifically, in FIG. 4, the distances L1 to L5 are the largest in the radial oil passages 91 and 95 on the left and right ends in the figure, the smallest in the middle radial oil passage 93 in the figure, and are represented by inequalities. L5> L4> L3 <L2 <L1. Therefore, each of the cross-sectional areas S1 to S5 is also qualitatively the same magnitude relationship, and expressed by an inequality, S5> S4> S3 <S2 <S1.

  The difference between the above-described cross-sectional areas S1 to S5 can be realized by increasing or decreasing the number of stacked first and second plates 51 and 52 constituting the rotor core 5A. Further, by adjusting the number of stacked third plates 53, the positions of the radial oil passages 91 to 95 in the axis AX direction can be adjusted. Since the other configuration of the second embodiment is the same as that of the first embodiment, description thereof is omitted.

  According to the motor cooling structure 1 </ b> A of the second embodiment, the fluid resistance regarding the radial oil passages 91 to 95 is equalized. For example, in the radial oil passage 91 at the right end in the figure, the partial fluid resistance is large depending on the large distance L1 in the axial oil passage 8A, and the large cross-sectional area S1 in the radial oil passage 91 is large. Depending on the partial fluid resistance is reduced. On the other hand, in the intermediate radial oil passage 93 in the figure, the partial fluid resistance is small depending on the small distance L3 in the axial oil passage 45, and the sectional area S3 in the radial oil passage 93 is small. Depending on it, the partial fluid resistance increases. That is, the total fluid resistance obtained by adding the two partial fluid resistances is equalized. As a result, the cooling oil is evenly distributed to the respective radial oil passages 91 to 95. Therefore, regardless of the position of the stator 6 in the axial direction AX, the cooling oil is evenly supplied to each part to be cooled uniformly, and a higher cooling capacity can be secured.

  Next, the motor cooling structure 1B of the third embodiment in which the radial oil passage is formed by the single slit hole 59 of the rotor core plate 5X (fourth plate) is mainly different from the first and second embodiments. Explained. FIG. 5 is a cross-sectional view schematically showing a motor cooling structure 1B of the third embodiment. Unlike the first and second embodiments, the upper radial oil passage 96 and the lower radial oil passage 97 in the figure of the rotor core 5B extend linearly in the radial direction. Further, the upper radial oil passage 96 and the lower radial oil passage 97 are alternately arranged in the axis AX direction.

  The rotor core 5B can be configured by stacking two types of rotor core plates 53 and 5X. FIG. 6 is a diagram illustrating the shapes of the two types of rotor core plates 53 and 5X constituting the rotor core 5B of the third embodiment. 6 (1) shows the shape of the third plate 53 without the slit hole 59 (the same shape as (3) of FIG. 3), and (2) shows the fourth type rotor core plate 5X with the slit hole 59 (hereinafter referred to as “3”). This is the shape of the fourth plate 5X.

  As shown in FIG. 6B, the fourth plate 5X has the same inner diameter, outer diameter, and band width W as the first to third plates 51 to 53, and the four magnetic pole holes 56 are provided. The same is true for the holes. Furthermore, a slit hole 59 that extends from the inner peripheral edge 54 to the outer peripheral edge 55 is formed in the fourth plate 5X. The slit hole 59 is disposed between the magnetic pole holes 56, and the slit width d is constant. As a result, the fourth plate 5X has a C-shape instead of an annular shape.

  As shown in FIG. 5, in the rotor core 5B, a plurality of third plates 53 are first laminated in the direction of the axis AX from an end plate 5E1 disposed on the outer periphery of the shaft 4 near the one end 41, and then a plurality of fourth plates. Plates 5X are stacked. An upper radial oil passage 96 is formed by the slit hole 59 of the fourth plate 5X. Subsequently, a plurality of third plates 53 are stacked, and then a plurality of fourth plates 5X are stacked at a phase rotated by 180 °. A lower radial oil passage 97 is formed by the slit hole 59 of the fourth plate 5X rotated by 180 °. Hereinafter, a plurality of third plates 53 and fourth plates 5X are alternately stacked, and finally, another end plate 5E2 is disposed near the other end 42 to constitute the rotor core 5B. Each of the radial oil passages 96 and 97 communicates with an axial oil passage 8 </ b> B formed by the axial groove 45 on the outer circumferential surface of the rotor 3.

  According to the motor cooling structure 1B of the third embodiment, since the positions of the upper and lower radial oil passages 96 and 97 in the axis AX direction are different, the cooling oil can be supplied to the stator 6 from a total of nine locations. Therefore, the cooling oil is more reliably supplied evenly without depending on the position of the stator 6 in the axial direction AX, and the cooling capacity is further ensured. Further, the rotor core plates 53 and 5X constituting the rotor core 5B may be of two types fewer than those of the first and second embodiments.

  Next, the motor cooling structures 1C and 1D of the fourth and fifth embodiments in which the shape of the oil passage is modified from the first embodiment will be described mainly with respect to differences from the first embodiment. FIG. 7 is a cross-sectional view schematically showing a motor cooling structure 1 </ b> C of the fourth embodiment in which the shape of the oil passage is modified from the first embodiment. In the fourth embodiment, a shaft end supply oil passage 44 </ b> C is provided instead of the shaft center supply oil passage 43 and the radial supply oil passage 44. More specifically, the axial groove 45C formed on the outer peripheral surface of the shaft 4C to form the axial oil passage 8C extends in the direction of the axis AX and reaches the other end 42 of the shaft 4C. A cylindrical cover 42C is disposed in the range where the rotor core 5 is not provided on the outer periphery of the axial groove 45C near the other end 42 of the shaft 4C, and the oil tightness of the axial groove 45C is ensured. A shaft end supply oil passage 44C is provided outside the other end 42 of the shaft 4C. The shaft end supply oil passage 44C communicates the suction oil pipe 71 and the axial groove 45C in an oil-tight manner.

  In the fourth embodiment, the supply position of the cooling oil to the axial groove 45C corresponding to the axial oil passage 8 changes to the axial end supply oil passage 44C, but from five locations on the outer peripheral surface of the rotor core 5 to various locations on the stator 6. The operation and effect of supplying a sufficient amount of cooling oil to the same are the same. When the cross-sectional area of each radial oil passage 9 is further changed in the fourth embodiment, the cross-sectional area of the radial oil passage 9 on the side close to the shaft end supply oil passage 44C (left side in FIG. 7) is reduced. To do.

  FIG. 8 is a cross-sectional view schematically showing a motor cooling structure 1D of the fifth embodiment in which the shape of the oil passage is modified from the first embodiment. In the fifth embodiment, an axial oil passage 8D extending in the direction of the axis AX is formed in the shaft center of the shaft 4D. The axial oil passage 8D opens at the other end 42 of the shaft 4D and communicates with the suction oil pipe 71 in an oil-tight manner. Further, a plurality of radial oil passages 44D branched from the axial oil passage 8D are formed in the shaft 4D. Each radial oil passage 44 </ b> D communicates with the inside of the radial oil passage 9 of the rotor core 5, i.e., the inner opening 571 of the inner slit hole 57.

  In the fifth embodiment, the supply position of the cooling oil in the axial oil passage 8 </ b> D changes to the other end 42 of the shaft 4 </ b> D, but a sufficient amount of cooling oil is supplied from five places on the outer peripheral surface of the rotor core 5 to each place on the stator 6. The functions and effects that can be supplied are the same. When the sectional area of each radial oil passage 9 is further changed in the fifth embodiment, the sectional area of the radial oil passage 9 on the side close to the other end 42 of the shaft 4D (left side in FIG. 7) is reduced. To do.

  Next, instead of the suction oil pipe 71 of the first embodiment, the motor cooling structures 1E and 1F of the sixth and seventh embodiments including the pumping oil pipe 75 and the oil pumps 76 and 77 are the same as those of the first embodiment. The differences are mainly explained. In the first embodiment, the number of rotations of the motor is relatively small, and therefore the suction pressure as a centrifugal pump is not so large, and the hydraulic pressure depends on the height of the supply position 81 of the axial oil passage 8 and the bottom of the case 2. The difference may not be secured. In this case, a pumping oil pipe 75 and a mechanical oil pump 76 are provided in place of the sucking oil pipe 71. FIG. 9 is a cross-sectional view schematically showing a motor cooling structure 1 </ b> E of the sixth embodiment including the pumping oil pipe 75 and the mechanical oil pump 76.

  The mechanical oil pump 76 is configured outside the other end 42 of the shaft 4 in the axis AX direction. The discharge side of the mechanical oil pump 76 communicates with the shaft supply oil passage 43, and the suction side communicates with the lower part of the case 2 by a pumping oil pipe 75. The mechanical oil pump 76 is driven by the rotation of the rotor 3, and pumps the cooling oil 29 at the lower part of the case 2 into the shaft center supply oil passage 43. There is no special restriction | limiting in the structure of the mechanical oil pump 76, A well-known various structure is employable.

  Even if the mechanical oil pump 76 is provided, the pump discharge pressure exceeding the hydraulic pressure difference depending on the height between the supply position 81 of the axial oil passage 8 and the bottom of the case 2 may not be ensured because the rotational speed of the motor is small. In this case, an electric oil pump 77 is used. FIG. 10 is a cross-sectional view schematically showing a motor cooling structure 1 </ b> F of the seventh embodiment including the pumping oil pipe 75 and the electric oil pump 77.

  The pumping oil pipe 75 communicates the shaft supply oil passage 43 and the lower part of the case 2. An electric oil pump 77 is provided in the middle of the pumping oil pipe 75. The electric oil pump 77 has a discharge pressure sufficient to pump up the cooling oil 29 at the lower part of the case 2 to the shaft center supply oil passage 43. The drive power source for the electric oil pump 77 may be shared with the motor body, or a separate power source may be used. If the electric oil pump 77 is used, the cooling oil can be reliably supplied regardless of the rotation speed of the motor body.

  According to the motor cooling structures 1E and 1F of the sixth and seventh embodiments, the cooling oil can be stably supplied to the axial oil passage 8 using a simple configuration. Moreover, since the effect | action and effect which cool the stator 6 and the rotor 3 are the same as that of 1st Embodiment, description is abbreviate | omitted.

  In addition, this invention is not limited to the above-mentioned 1st-7th embodiment, Various application and deformation | transformation are possible. For example, by providing slit holes 57, 58, 59 formed in the rotor core plates 51-53, 5X at four positions at a 90 ° pitch, or by changing the lamination method of the rotor core plates 51-53, 5X, various shapes can be obtained. A radial oil passage can be formed.

DESCRIPTION OF SYMBOLS 1, 1A-1F: Motor cooling structure 2: Case 21: Case cylinder part 22, 23: Case side part 29: Cooling oil 3: Rotor 4, 4C, 4D: Shaft 41: One end 42: Other end 43: Axis center Supply oil passage 44: Radial supply oil passage 45: Axial groove 5, 5A, 5B: Rotor core 51-53, 5X: Rotor core plate (first to fourth plates)
54: Inner peripheral edge 55: Outer peripheral edge 56: Magnetic pole hole 57: Inner slit hole 58: Outer slit hole 59: Slit hole 5E1, 5E2: End plate 5M: Permanent magnet 6: Stator 61: Stator core 62: Magnetic pole teeth
63: Slot space 65: Coil 71: Suction oil pipe 75: Pumping oil pipe 76 Mechanical oil pump 77: Electric oil pump 8, 8A-8D: Axial oil path 81, 81A: Cooling oil supply position 9, 91-97 : Radial oil passage W: Band width d: Slit width L1 to L5: Distances between the supply position of the cooling oil and the branch position of the radial oil passage S1 to S5: Cross sectional areas of the radial oil passage

Claims (5)

A motor comprising: a case in which cooling oil is enclosed; a rotor that is rotatably supported around the axis around the case; and a stator that is coaxially spaced apart from the outer periphery of the rotor and fixed to the case. A cooling structure,
The rotor extends in the axial direction and is supplied with the cooling oil, and a plurality of openings that are branched from the axial oil path and opened at a plurality of locations separated in the axial direction of the outer circumferential surface of the rotor. A cooling structure for a motor having a radial oil passage. In claim 1,
The rotor is configured to include a shaft disposed on the axis, and a cylindrical rotor core integrally assembled to the outer periphery of the shaft,
The axial oil passage is formed by an axial groove engraved in the axial direction on the outer peripheral surface of the shaft,
The radial oil passage is formed by a radial hole bored in the rotor core in the radial direction, an inner side opening in the core inner peripheral surface and facing the axial groove of the shaft, and an outer side opening in the core outer peripheral surface. Formed,
The stator is a motor cooling structure including a cylindrical stator core having magnetic pole teeth and a slot space on the inner peripheral side, and a coil having a conductor disposed in the slot space. In claim 2,
The rotor core is configured by laminating a plurality of annular thin rotor core plates in the axial direction,
Some rotor core plates have a bottomed inner slit hole that opens to the inner peripheral surface of the core and faces the axial groove of the shaft, and another rotor core plate adjacent to the rotor core plate is A bottomed outer slit hole opened on the outer peripheral surface of the core, and the inner slit hole and the outer slit hole communicate with each other inside the rotor core to become the radial hole, thereby forming the radial oil passage. Motor cooling structure.   4. The diameter according to any one of claims 1 to 3, wherein the smaller the distance, the smaller the distance according to each distance between the cooling oil supply position in the axial oil path and the branch positions of the plurality of radial oil paths. A motor cooling structure in which the cross-sectional area of the directional oil passage is small and the cross-sectional area of the radial oil passage is large as the distance is large. In any one of Claims 1-4,
A suction oil passage that communicates between the supply position of the cooling oil in the axial oil passage and a bottom portion in which the cooling oil stays in the case;
Alternatively, a pumping oil passage communicating the supply position of the cooling oil in the axial oil passage and a bottom portion where the cooling oil stays in the case, and an oil pump disposed in the middle of the pumping oil passage The motor cooling structure further comprising:

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