JP6661458B2 - Rotor and electric motor - Google Patents

Description

  The present invention relates to a rotor and an electric motor.

  Patent Literature 1 discloses a technique in which a flow path is formed in a rotor core of an electric motor used for driving a construction machine or the like, and cooling oil is circulated through the flow path to cool the rotor core.

JP 2007-20337 A

In order to improve the performance of the electric motor, it is required that both the cooling of the rotor core and the reduction of the moment of inertia of the rotor at the time of rotational driving are compatible.
The present invention has been made in view of such problems, and has as its object to provide a rotor capable of improving the performance of an electric motor and an electric motor including the same.

A rotor according to a first aspect of the present invention includes a shaft extending along an axis, a plurality of steel plates stacked in the axial direction, a rotor core fixed to a radially outer side of the shaft, and a rotor core. Fixed, a plurality of permanent magnets arranged at intervals in the circumferential direction of the shaft, and a pair of end plates provided so as to sandwich the rotor core from both sides in the axial direction, the rotor core, A first axial flow path that extends in the axial direction and through which the cooling oil flows, and communicates with the first axial flow path, and extends in the axial direction inside the radial direction of the first axial flow path. a secondary axial flow path, the the first axial passage and the second axial channels independently, the first axial passage and the radially inner than the permanent magnet and the second The diameter from the axial flow path With the formed in Kosotogawa, having a void portion that is formed to cover the second axial flow path from said radially outer side.

An electric motor according to a second aspect of the present invention includes a shaft extending along an axis, a rotor core fixed radially outside the shaft, and a plurality of permanent magnets arranged in the rotor core at intervals in a circumferential direction of the shaft. Magnet, and a rotor having a pair of end plates provided so as to sandwich the rotor core from both sides in the axial direction, a stator core surrounding the rotor from the outer peripheral side, and fixed to the stator core to be circumferentially spaced apart from each other. And a stator having a plurality of spaced coils, wherein the shaft extends from one axial end of the shaft to the axial position corresponding to one axial end of the rotor core. A shaft central hole extending from the shaft central hole to a shaft radial hole extending from the shaft central hole to an outer peripheral surface of the shaft; The core has a first flow path forming hole, a through hole, and a second flow path forming hole penetrating in the axial direction, and a plurality of first steel plates stacked in the axial direction with each other, and penetrating in the axial direction. Having a first flow path forming hole, and a second flow path forming hole, further comprising at least one second steel sheet laminated on the plurality of first steel sheets laminated on each other from the other side in the axial direction. A first axial flow path extending in the axial direction along the permanent magnet is defined by the first flow path forming holes of the first steel sheet and the second steel sheet, and the first hole of the first steel sheet is formed by: Independently of the first axial flow path, a gap located radially inside the first axial flow path is defined, and the lower end of the gap is closed by the second steel plate, Outer peripheral surfaces of the shaft and the second channel forming holes of the first steel plate and the second steel plate Second axial passage which communicates with the shaft radial holes at the top and extends in the axial direction in the radial inner side of the gap portion is defined by the gap portion, the second axial passage The end plate on the other side in the axial direction of the pair of end plates is formed so as to cover from the outside in the radial direction , and has a concave portion that is depressed from a surface facing one side in the axial direction. The second steel plate defines a radial flow path that extends in the radial direction and communicates with the lower end of the first axial flow path and the lower end of the second axial flow path. The end plate on one side in the axial direction has a through hole penetrating in the axial direction and connected to the first axial flow path, and closes the gap from one side in the axial direction.

  According to at least one of the above aspects, the performance of the electric motor can be improved.

It is a side view of the construction machine provided with the electric motor concerning a first embodiment of the present invention. It is a top view of the construction machine provided with the electric motor concerning a first embodiment of the present invention. It is a longitudinal section of the electric motor concerning a first embodiment of the present invention. It is a typical longitudinal section showing a part of rotor of the electric motor concerning a first embodiment of the present invention. FIG. 5 is a sectional view taken along line VV of FIG. 4. FIG. 6 is a sectional view taken along line VI-VI of FIG. 4. It is a longitudinal section showing the lamination state of the 1st steel plate and the 2nd steel plate in the rotor core of the electric motor concerning a first embodiment of the present invention. FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 4. FIG. 9 is a sectional view taken along line IX-IX of FIG. 4. It is a longitudinal section showing a part of rotor concerning a second embodiment of the present invention typically. It is a longitudinal section showing a part of rotor concerning a third embodiment of the present invention typically. It is a longitudinal section showing a part of rotor concerning a 4th embodiment of the present invention typically. It is a longitudinal section showing typically a part of rotor concerning a fifth embodiment of the present invention. It is a longitudinal section of the electric motor concerning a 6th embodiment of the present invention.

<First embodiment>
Hereinafter, an electric motor including the rotor of the present invention and a construction machine including the electric motor will be described in detail with reference to FIGS. 1 to 9.

<Construction machinery>
As shown in FIGS. 1 and 2, a hydraulic excavator 100 as a construction machine includes a lower traveling unit 110, a swing circle 120, and an upper revolving unit 130. In the following, the direction in which gravity acts when the construction machine is installed on a horizontal surface is referred to as the “vertical direction”.
The lower traveling body 110 has a pair of left and right crawler belts 111, 111. The crawler belts 111, 111 are driven by a traveling hydraulic motor (not shown) to cause the hydraulic excavator 100 to travel.

  The swing circle 120 is a member that connects the lower traveling structure 110 and the upper revolving structure 130, and includes an outer race 121, an inner race 122, and a swing pinion 123. The outer race 121 is supported by the lower traveling body 110 and has an annular shape centered on a turning axis L extending in the vertical direction. The inner race 122 is an annular member coaxial with the outer race 121, and is disposed inside the outer race 121. The inner race 122 is supported so as to be rotatable relative to the outer race 121 around the rotation axis L. The swing pinion 123 meshes with the internal teeth of the inner race 122, and the rotation of the swing pinion 123 causes the inner race 122 to rotate relative to the outer race 121.

  The upper revolving unit 130 is disposed so as to be rotatable around the revolving axis L with respect to the lower traveling unit 110 by being supported by the inner race 122. The upper swing body 130 includes a cab 131, a working machine 132, an engine 136 provided behind these, a generator motor 137, a hydraulic pump 138, an inverter 139, a capacitor 140, and the electric motor 1 as a swing motor. .

  The cab 131 is disposed on the front left side of the upper swing body 130, and has a driver's seat for the operator. The work machine 132 is provided so as to extend forward of the upper swing body 130, and has a boom 133, an arm 134, and a bucket 135. The work machine 132 performs various operations such as excavation by driving the boom 133, the arm 134, and the bucket 135 by respective hydraulic cylinders (not shown).

  The rotation shafts of the engine 136 and the generator motor 137 are spline-coupled to each other. The generator motor 137 generates electric power by being driven by the engine 136. The rotating shafts of the generator motor 137 and the hydraulic pump 138 are spline-coupled to each other. The hydraulic pump 138 is driven by the engine 136. The hydraulic pressure generated by driving the hydraulic pump 138 drives the traveling hydraulic motor and each hydraulic cylinder described above.

The generator motor 137, the capacitor 140 and the electric motor 1 are electrically connected to each other via an inverter 139.
The electric motor 1 is arranged in a vertically installed state in which an axis O serving as a rotation center coincides with the vertical direction. The output of the electric motor 1 is transmitted to the swing pinion 123 meshed with the inner teeth of the inner race 122.

The hydraulic excavator 100 drives the electric motor 1 with electric power generated by the generator motor 137. The driving force of the electric motor 1 is transmitted to the inner race 122 via the swing pinion 123. As a result, the inner race 122 rotates relative to the outer race 121, so that the upper swing body 130 turns.
At the time of deceleration of the rotation of the upper swing body 130, the electric motor 1 functions as a generator to generate electric power as regenerative energy. This power is stored in the capacitor 140 via the inverter 139. The electric power stored in the capacitor 140 is supplied to the generator motor 137 when the engine 136 is accelerated. When the generator motor 137 is driven by the power of the capacitor, the generator motor 137 assists the output of the engine 136.

<Electric motor>
As shown in FIG. 3, the electric motor 1 includes a casing 2, a cooling oil supply unit 20, a stator 30, and a rotor 40.
<Casing>
The casing 2 is a member that forms the outer shape of the electric motor 1. The casing 2 includes a cylindrical portion 3 having a cylindrical shape extending in the up-down direction (the direction of the axis O) and having an inner space as the accommodation space, and a first lid portion 4 and a second lid portion 7 for closing the accommodation space from above and below. Have.

  At the center of the first lid part 4, a shaft housing part 5 protruding upward (one side in the direction of the axis O) is formed. A cooling oil introduction hole 6 is formed in a portion on the upper end side of the shaft housing portion 5 as a flow path penetrating the shaft housing portion 5 along the axis O. A first bearing 11 having an annular shape about the axis O and a first seal portion 13 disposed above the first bearing 11 are fixed to the inner peripheral surface of the shaft housing portion 5.

  At the center of the second lid part 7, a shaft penetration part 8 is formed which extends cylindrically downward (the other side in the direction of the axis O) and communicates the housing space and the external space vertically. A second bearing 12 having an annular shape about the axis O and a second seal portion 14 disposed below the second bearing 12 are fixed to the inner peripheral surface of the shaft penetration portion 8. The second lid portion 7 is provided with a cooling oil discharge passage 9 for discharging the cooling oil in the housing space to the outside by connecting the housing space to the outside.

<Cooling oil supply unit>
The cooling oil supply section 20 supplies cooling oil into the casing 2. In the present embodiment, the cooling oil supplied into the casing 2 is recovered, cooled, and then supplied into the casing 2 again. That is, the cooling oil is circulated by the cooling oil supply unit 20.
The cooling oil supply section 20 includes a cooling oil storage section 21, an introduction flow path 22, a return flow path 23, a cooling oil pump 24, and a cooling section 25.

  The cooling oil storage unit 21 stores cooling oil. The upstream end of the introduction flow path 22 is connected to the cooling oil reservoir 21, and the downstream end is externally connected to the cooling oil introduction hole 6 in the casing 2. The recirculation flow path 23 has an upstream end connected to the cooling oil discharge passage 9 in the casing 2 from the outside, and a downstream end connected to the cooling oil storage 21. The cooling oil pump 24 is provided in the introduction flow path 22 and pumps the cooling oil in the cooling oil storage section 21 to the cooling oil introduction hole 6 of the casing 2 via the introduction flow path 22. The cooling unit 25 is provided in the return flow path 23 and cools the cooling oil discharged from the cooling oil discharge path 9 of the casing 2 and flowing through the return flow path 23. The cooling unit 25 cools the cooling oil by exchanging heat between, for example, external air and the cooling oil.

<Stator>
The stator 30 includes a stator core 31 and a coil 34.
The stator core 31 has a cylindrical shape centered on the axis O and has an outer peripheral surface fixed to the inner peripheral surface of the casing 2, and a circumferential direction of the yoke 32 protruding from the inner peripheral surface of the yoke 32. And a plurality of teeth 33 formed at intervals. The stator core 31 is configured by stacking a plurality of electromagnetic steel sheets in the vertical direction.
A plurality of coils 34 are provided so as to correspond to the respective teeth 33, and are wound around the respective teeth 33. Thus, a plurality of coils 34 are provided at intervals in the circumferential direction.

<Rotor>
The rotor 40 includes a shaft 41, a rotor core 50, a permanent magnet 80, a first end plate 90, and a second end plate 96 (a pair of end plates).

<Shaft>
The shaft 41 is a rod-shaped member extending along the axis O. Hereinafter, the radial direction of the shaft 41 is simply referred to as “radial direction”, and the circumferential direction of the shaft 41 is simply referred to as “circumferential direction”.
The shaft 41 is disposed so as to penetrate the inside of the stator 30 in the casing 2 in the up-down direction. The upper end of the shaft 41 extends into the shaft housing 5 in the casing 2. The lower end of the shaft 41 extends through the shaft penetration 8 of the casing 2 to the outside of the casing 2. The shaft 41 is supported by the first bearing 11 and the second bearing 12 so as to be relatively rotatable around the axis O with respect to the casing 2. The outer peripheral surface of the shaft 41 is in contact with the first seal portion 13 and the second seal portion 14, and the liquid tightness at the place where the first seal portion 13 and the second seal portion 14 are installed is secured.

  At a part of the outer peripheral surface of the shaft 41 in the up-down direction, a step portion 42 that protrudes radially outward over the entire circumferential direction is provided. A part of the outer peripheral surface of the shaft 41 from the step portion 42 upward is a fixed surface 43 on which the rotor core 50, the first end plate 90, and the second end plate 96 are fitted.

The shaft 41 has a shaft center hole 44 extending downward from the upper end of the shaft 41, and a shaft radial hole 45 extending from the shaft center hole 44 to the outer peripheral surface of the shaft 41.
The shaft center hole 44 does not extend over the entire area of the shaft 41 in the up-down direction, but extends from the upper end of the shaft 41 to the middle thereof. Thus, the shaft 41 has a hollow structure at the portion where the shaft center hole 44 is formed from the upper end to the lower end, and has a solid structure at the remaining lower portion.

The shaft radial hole 45 extends in the radial direction so that the extending direction matches the direction orthogonal to the axis O. A radially inner end of the shaft radial hole 45 communicates with a lower end of the shaft center hole 44. In other words, the shaft center hole 44 extends only up and down the shaft radial hole 45 and does not extend below the shaft radial hole 45.
The radially outer end of the shaft radial hole 45 is open to the fixed surface 43 on the outer peripheral surface of the shaft 41. A plurality of shaft radial holes 45 are formed at intervals in the circumferential direction. In this embodiment, a total of four shaft radial holes 45 are formed radially at 90 ° intervals in the circumferential direction.

<Rotor core>
As shown in FIGS. 3 and 4, the rotor core 50 has a cylindrical outer shape as a whole, and is externally fitted to the fixed surface 43 on the outer peripheral surface of the shaft 41. The upper end of the rotor core 50 externally fitted to the shaft 41 is at a vertical position corresponding to the lower end of the shaft center hole 44. In other words, the shaft center hole 44 extends downward from the upper end of the shaft toward the end to a vertical position corresponding to the upper end of the rotor core 50. The shaft radial hole 45 is also located at a vertical position corresponding to the upper end of the rotor core.

In the rotor core 50, a core central hole 51, a magnet embedding portion 52, a first axial flow path 53, a second axial flow path 54, and a void 55 are formed.
The core center hole 51 is a hole formed at the center of the rotor core 50 so as to penetrate the rotor core 50 in the vertical direction. The core central hole 51 has a circular cross section perpendicular to the axis O. The rotor core 50 is externally fitted to the fixed surface 43 of the shaft 41 via the core center hole 51.

  The magnet embedding portion 52 is a plurality of holes formed at an outer circumferential side portion in the rotor core 50 at intervals in the circumferential direction. The magnet embedded portion 52 extends in a uniform shape over the entire area of the rotor core 50 in the vertical direction. The magnet embedded portion 52 is open at the upper end and the lower end of the rotor core 50.

  The plurality of first axial flow paths 53 are formed in the outer peripheral portion of the rotor core 50 at intervals in the circumferential direction. The first axial flow path 53 extends in a uniform shape over the entire vertical region of the rotor core 50. The first axial flow path 53 opens at the upper and lower ends of the rotor core 50. In the present embodiment, the first axial flow path 53 is formed integrally with the magnet embedding part 52, that is, the first axial flow path 53 and the magnet embedding part 52 are continuous with each other when viewed in the axis O direction. are doing.

  The plurality of second axial flow paths 54 are formed in the inner peripheral portion of the rotor core 50 at intervals in the circumferential direction. The second axial flow path 54 extends in a uniform shape over the entire vertical region of the rotor core 50. The second axial flow path 54 is open at the upper end and the lower end of the rotor core 50. In the present embodiment, the second axial flow path 54 is formed so as to be in contact with the outer peripheral surface of the shaft 41 along the fixed surface 43. The upper end of the second axial flow path 54 communicates with the radially outer end of the shaft radial hole 45. In other words, the shaft radial hole 45 is located at a vertical position connected to the upper end of the second axial flow path 54.

  The plurality of gaps 55 are formed at radial positions between the magnet embedding section 52 and the second axial flow path 54 in the rotor core 50 and are spaced apart from each other in the circumferential direction. The air gap 55 extends in the rotor core 50 in a uniform shape in the vertical direction, and opens at the upper end of the rotor core 50. The gap 55 does not open at the lower end of the rotor core 50. That is, the gap 55 is opened only at the upper end of the rotor core 50. The air gap 55 is independently isolated from the magnet embedding part 52 and the second axial flow path 54 in the rotor core 50. Thus, the gap 55 is in a non-communication state with the magnet embedded portion 52 and the second axial flow path 54 in the rotor core 50.

  As shown in FIG. 4, the rotor core 50 is configured by vertically stacking a plurality of electromagnetic steel sheets (steel sheets). The rotor core 50 includes, as electromagnetic steel sheets, a plurality of first steel sheets 60 stacked on each other and one second steel sheet 70 further stacked from below the first steel sheets 60 stacked on each other.

<First steel plate>
As shown in FIG. 5, the first steel plate 60 is a disk-shaped member that extends in a direction perpendicular to the axis O and has a circular outer shape around the axis O. Each first steel plate 60 has the same shape.
In the center of the first steel plate 60, a steel plate center hole 61 is formed which has a circular shape centered on the axis O and penetrates in the vertical direction.

  In the radially outer portion of the first steel plate 60, a plurality of embedded portion forming holes 62 penetrating the first steel plate 60 are formed at intervals in the circumferential direction so as to form a long hole when viewed in the direction of the axis O. I have. The buried portion forming holes 62 are arranged such that a pair of buried portion forming holes 62, 62 form a V-shape that protrudes radially inward. In the present embodiment, a total of eight sets are provided at equal intervals in the circumferential direction.

  A pair of first flow path forming holes 63, 63 penetrating the first steel plate 60 are formed at the apexes of the V-shaped portions of the embedding part forming holes 62, 62 of each set. The pair of first flow path forming holes 63, 63 are arranged so as to face each other in the circumferential direction at locations corresponding to the V-shaped vertices of the embedding portion forming holes 62, 62. Eight sets of the pair of first flow path forming holes 63, 63 are provided at equal intervals in the circumferential direction, similarly to the embedding portion forming holes 62, 62 of each set. In the present embodiment, each first flow path forming hole 63 is formed integrally with the buried part forming hole 62, that is, the first flow path forming hole 63 and the buried part forming hole 62 are continuous with each other when viewed in the axis O direction. are doing.

A barrier forming hole 64 penetrating through the first steel plate 60 so as to be integral with the embedded portion forming hole 62 so as to be continuous with the embedded portion forming hole 62 is provided on the opposite side of the V-shaped apex of the embedded portion forming holes 62, 62 of each set. Is formed.
In the first steel plate 60 of the present embodiment, from the outside in the radial direction, that is, from the outside of the V-shape to the inside, the barrier forming hole 64, the buried portion forming hole 62, and the first flow path forming hole. 63 are formed integrally and continuously.

  A plurality of punched holes 65 penetrating in the vertical direction and extending in an arc shape in the circumferential direction are formed at a radially inner side of the first flow path forming hole 63 in the first steel plate 60 at intervals in the circumferential direction. In the present embodiment, eight holes 65 are formed at regular intervals in the circumferential direction. The portion between the pair of adjacent holes 65 is located at the same circumferential position as the V-shaped apexes of the embedding portion forming holes 62 of each pair.

  A plurality of second flow path forming holes 66 penetrating in the vertical direction are formed in the first steel plate 60 further radially inward of the holes 65 in the first steel plate 60 at intervals in the circumferential direction. In the present embodiment, four second flow path forming holes 66 are formed at 90 ° intervals in the circumferential direction. These second flow path forming holes 66 are provided so as to correspond to circumferential positions of four of the eight drawing holes 65, and each of the second flow path forming holes 66 is a corresponding drawing hole. 65 are respectively covered from the outer peripheral side. The second flow path forming hole 66 of the present embodiment is formed so as to be depressed in an arc shape radially outward from the outer periphery of the steel plate center hole 61. That is, the second flow path forming hole 66 is formed continuously with the steel plate central hole 61 so as to be integral with the steel plate central hole 61.

  At the radial position between the embedded portion forming hole 62 and the punched hole 65 in the first steel plate 60, a plurality of crimping convex portions 67 are formed at intervals in the circumferential direction. The caulking convex portion 67 is a so-called V-caulking formed so that a part of the first steel plate 60 projects downward. In the present embodiment, the eight crimping protrusions 67 are formed at the same circumferential position as the eight holes 65 so as to be equally spaced in the circumferential direction.

<Second steel plate>
As shown in FIG. 6, the second steel plate 70 is a disk-shaped member that extends in a direction perpendicular to the axis O and has a circular outer shape around the axis O. The outer shape of the second steel plate 70 is the same as the outer shape of the first steel plate 60. The second steel plate 70 has the same shape and arrangement as the steel plate center hole 61, the embedded portion forming hole 62, the first flow passage forming hole 63, the barrier forming hole 64, and the second flow passage forming hole 66 of the first steel plate 60. A steel plate center hole 71, a buried portion forming hole 72, a first flow passage forming hole 73, a barrier forming hole 74, and a second flow passage forming hole 76 are formed.

The second steel plate 70 does not have the same hole as the hole 65 of the first steel plate 60.
A plurality of caulking holes 77 penetrating vertically are formed in the second steel plate 70 at intervals in the circumferential direction. A total of eight caulking holes 77 are provided so as to correspond to the caulking protrusions 67 of the first steel plate 60. The caulking holes 77 are provided at the same circumferential position and radial position as the caulking protrusions 67 of the first steel plate 60.
The second steel plate 70 is different from the first steel plate 60 in that the hole 65 is not formed and the hole 77 for caulking is formed instead of the convex portion 67 for caulking.

<Lamination of first and second steel sheets>
As shown in FIG. 7, the plurality of first steel plates 60 are fixedly integrated by the fact that the caulking convex portions 67 are sequentially fitted in the vertical direction. One second steel plate 70 is fixedly integrated with the first steel plate 60 by fitting the caulking convex portion 67 of the lowermost first steel plate 60 of the plurality of first steel plates 60 laminated together. Have been. Thus, a rotor core 50 having a cylindrical shape as a whole is configured.

  The plurality of first steel plates 60 and one second steel plate 70 are stacked on each other, so that the core center hole 51, the magnet embedded portion 52, and the like described above in the rotor core 50, as shown in FIGS. A first axial flow path 53, a second axial flow path 54, and a gap 55 are defined.

The core center hole 51 is defined by the steel plate center holes 61 and 71 in the plurality of first steel plates 60 and one second steel plate 70 that are stacked on each other.
The magnet embedded portion 52 is defined by embedded portion forming holes 62 and 72 in the plurality of first steel plates 60 and one second steel plate 70 stacked on each other.
The first axial flow path 53 is defined by the first flow path forming holes 63 and 73 in the plurality of first steel sheets 60 and one second steel sheet 70 stacked on each other.
The second axial flow passage 54 is defined by a plurality of first steel plates 60 and second flow passage forming holes 66 and 76 of one second steel plate 70 that are stacked on each other.
The gap 55 is defined by the holes 65 of the plurality of first steel plates 60 stacked on each other. The gap 55 is closed from below by the second steel plate 70 disposed at the lowest position of the rotor core 50.

  Further, as shown in FIGS. 5 and 6, the flux barrier portion 56 (see FIG. 5) is formed in the rotor core 50 by the barrier forming holes 64 and 74 of the plurality of first steel plates 60 and one second steel plate 70 stacked on each other. 3, 4) are formed. The flux barrier portion 56 extends in a uniform shape over the entire vertical region of the rotor core 50. The flux barrier 56 is open at the upper and lower ends of the rotor core 50.

  The shapes and arrangement relations of the core central hole 51, the magnet embedding portion 52, the first axial channel 53, the flux barrier portion 56, and the second axial channel 54 as viewed in the axis O direction are as follows. In the steel sheet 70, the central holes 61 and 71, the embedment forming holes 62 and 72, the first flow path forming holes 63 and 73, the barrier forming holes 64 and 74, and the second flow path forming holes 66 and 76 as viewed in the direction of the axis O of the steel plate 70. Is the same as the shape and arrangement relationship in. The shape and the positional relationship of the gap 55 in the direction of the axis O are the same as the shape and the positional relationship of the hole 65 in the first steel plate 60.

  That is, the magnet embedding portions 52, 52 are formed in a pair on the outer peripheral side of the rotor core 50 so as to form a V-shape, and the V-shaped sets are spaced apart in the circumferential direction. A plurality is arranged. A pair of the first axial flow paths 53 is disposed on the vertex side of each set of the magnet embedded portions 52, 52. The flux barrier portions 56 are arranged on the magnet embedded portions 52, 52 on the side opposite to the V-shaped apex side. The magnet embedded portion 52, the first axial flow path 53, and the flux barrier portion 56 are continuous with each other when viewed in the direction of the axis O. The air gap 55 is disposed radially inside the magnet embedding part 52, the first axial flow path 53, and the flux barrier part 56. A second axial flow path 54 is disposed radially inward of the gap 55. In other words, the gap 55 is disposed so as to be sandwiched between the first axial channel 53 and the second axial channel 54 from the radial direction.

<Permanent magnet>
As shown in FIGS. 3 and 4, the permanent magnet 80 has a long shape extending over the entire area of the rotor core 50 in the vertical direction. A plurality of permanent magnets 80 are fixed to the rotor core 50 at intervals in the circumferential direction.

  In this embodiment, as shown in FIGS. 5 and 6, each permanent magnet 80 is fixed to the rotor core 50 in the magnet embedded portion 52 by being inserted into the magnet embedded portion 52. The permanent magnet 80 has a rectangular cross section perpendicular to the axis O. A pair of long sides of the rectangular cross section of the permanent magnet 80 are in contact with the inner surface of the magnet embedded portion 52. One of a pair of short sides of the cross section rectangle of the permanent magnet 80 faces the first axial flow path 53. That is, the first axial channel 53 is defined by a surface including one short side of the permanent magnet 80 in addition to the first channel forming holes 63 and 73 of the first steel plate 60 and the second steel plate 70. Accordingly, the first axial flow path 53 is in contact with the permanent magnet 80 over the entire vertical region of the rotor core 50, that is, over the entire vertical region of the permanent magnet 80.

  The other of the pair of short sides of the permanent magnet 80 faces the flux barrier portion 56. That is, the flux barrier portion 56 is defined by a surface including the other short side of the permanent magnet 80 in addition to the barrier forming holes 64 and 74 of the first steel plate 60 and the second steel plate 70.

  The permanent magnets 80 are installed such that the polarities of adjacent magnetic poles are different from each other. One magnetic pole is formed by a pair of permanent magnets 80, 80 which form a V-shape as viewed in the direction of the axis O similarly to the set of magnet embedded portions 52, 52. In the present embodiment, since a set of eight V-shaped magnet embedded portions 52, 52 is formed, the permanent magnet 80 is fixed to these magnet embedded portions 52, so that the rotor 40 has eight poles. It is a pole.

<First end plate>
The first end plate 90 is a disk-shaped member that extends in a direction perpendicular to the axis O and has a circular outer shape around the axis O, as shown in FIGS. 3 and 4. The first end plate 90 is fixed so as to be stacked on the rotor core 50 from below the rotor core 50. That is, the first end plate 90 is laminated on the second steel plate 70 of the rotor core 50 from below. The first end plate 90 is formed with a circular hole 91 having a circular shape centered on the axis O in the center. The first end plate 90 is fixed to the shaft 41 by fitting the circular hole 91 to the fixing surface 43 on the outer peripheral surface of the shaft 41. The downwardly facing surface of the first end plate 90 is in contact with the step 42 of the shaft 41 from above.

A radial passage 92 extending in the radial direction is formed in the first end plate 90. The radial flow path 92 connects the first axial flow path 53 and the second axial flow path 54 of the rotor core 50 in the radial direction. In the present embodiment, the radial channel 92 is in communication with the shaft radial hole 45 in the shaft 41 via the second axial channel 54. The radial channel 92 is defined by a concave portion 93 formed in the first end plate 90 and the second steel plate 70 with which the first end plate 90 contacts from below.
The plurality of recesses 93 are formed at intervals in the circumferential direction so as to be depressed from a surface facing upward of the first end plate 90, that is, a surface in contact with the second steel plate 70. In the present embodiment, as shown in FIG. 8, four concave portions 93 are formed at equal intervals in the circumferential direction.

  Each recess 93 is formed by a pair of radial flow path forming portions 94 extending in the radial direction. The pair of radial flow path forming portions 94 and 94 have radial inner ends joined to each other and connected to the circular hole 91. The pair of radial flow path forming portions 94, 94 are branched so as to gradually become circumferentially separated toward the outside in the radial direction. Thus, each recess 93 has a V-shape with its apex facing radially inward. The radially outer ends of the pair of radial flow path forming portions 94 in each recess 93 are closed without opening to the outer peripheral surface of the first end plate 90.

The circumferential position of a portion corresponding to the V-shaped vertex of each recess 93 is the same as the circumferential position of the second axial flow path 54 of the rotor core 50. The positions of the radially outer ends of the pair of radial flow path forming portions 94 and 94 in each recess 93 include a pair of first axial flow paths 53 that are close to each other in the rotor core 50 as viewed in the direction of the axis O. Position.
When the first end plate 90 is laminated on the second steel plate 70, the radial flow passage 92 defined by the concave portion 93 and the second steel plate 70 forms the first axial flow passage 53 of the rotor core 50 and the second axial flow passage 92. The flow path 54 is radially communicated with the flow path 54. The radial flow path 92 is separated from the gap 55 by the second steel plate 70 so as to be independent. In the present embodiment, since a total of eight radial flow path forming portions are formed, eight radial flow paths 92 are defined when viewed in the direction of the axis O.

<Second end plate>
As shown in FIGS. 3 and 4, the second end plate 96 extends in a direction perpendicular to the axis O, and has a circular outer shape around the axis O, similarly to the first end plate 90. -Shaped member. The second end plate 96 is fixed so as to be stacked on the rotor core 50 from above the rotor core 50. That is, the second end plate 96 is stacked from above on the first steel plate 60 disposed at the uppermost position among the plurality of first steel plates 60 in the rotor core 50. The second end plate 96 is formed with a circular hole 97 having a circular shape centered on the axis O in the center. The second end plate 96 is fixed to the shaft 41 by fitting the circular hole 97 to the fixing surface 43 on the outer peripheral surface of the shaft 41. The second end plate 96 and the first end plate 90 support the rotor core 50 so as to sandwich the rotor core 50 from above and below.

The second end plate 96 closes the gap 55 in the rotor core 50 from above by a surface facing downward. The gap 55 is closed by the second steel plate 70 at the lower end and closed by the second end plate 96 at the upper end to form a closed space isolated from the outside.
The second end plate 96 closes the second axial flow path 54 in the rotor core 50 from above by a surface facing downward.
As shown in FIG. 9, a plurality of through holes 98 penetrating in the vertical direction are formed in the second end plate 96 at intervals in the circumferential direction. In the present embodiment, a total of eight through holes 98 are formed at regular intervals in the circumferential direction.

The position of each through hole 98 is a position including a pair of first axial flow paths 53 that are close to each other in the rotor core 50 as viewed in the axis O direction. Thereby, the through hole 98 of the second end plate 96 and the first axial flow path 53 of the rotor core 50 communicate with each other.
As a result, cooling oil is supplied in the rotor 40 in the order of the shaft center hole 44, the shaft radial hole 45, the second axial flow passage 54, the radial flow passage 92, the first axial flow passage 53, and the through hole 98. A flowing cooling channel is formed.

<Operation and effects of motor>
When the electric motor 1 is driven, AC power is supplied to the coils 34 of the stator 30 via the inverter 139, and the permanent magnets 80 follow the rotating magnetic field generated by the coils 34, so that the rotor 40 Rotate. When the upper swing body 130 of the construction machine turns, the electric motor 1 is driven with high torque. Therefore, the rotor core 50 and the permanent magnet 80 become hot due to the iron loss in the rotor core 50 and the eddy current loss in the permanent magnet 80, and the stator 30 becomes hot due to the copper loss in the coil 34 and the iron loss in the stator core 31. When the temperature of the stator 30 increases, the temperature of the rotor core 50 further increases due to the radiation heat of the stator 30. Therefore, cooling oil is supplied into the electric motor 1 by the cooling oil supply unit 20.

  When the cooling oil pump 24 of the cooling oil supply unit 20 operates, the cooling oil of the cooling oil storage unit 21 is supplied to the cooling oil introduction hole 6 of the casing 2 of the electric motor 1 via the introduction flow path 22. The cooling oil flowing through the cooling oil introduction hole 6 is introduced into the shaft center hole 44 from the upper end of the shaft 41 of the rotor 40 that is driven to rotate. The cooling oil flowing downward in the shaft center hole 44 is introduced into the shaft radial hole 45 branched from the shaft center hole 44 and flows radially outward. When the cooling oil reaches the outer peripheral surface of the shaft 41 through the shaft radial hole 45, the cooling oil is introduced into the upper end of the second axial flow path 54 in the rotor core 50. The cooling oil flows downward in the second axial flow path 54 along the outer peripheral surface of the shaft 41, and when the cooling oil reaches the first end plate 90 from the rotor core 50, the radial oil flows in the first end plate 90. Introduced into road 92.

  After the cooling oil flows radially outward in the radial flow path 92, it is introduced into the first axial flow path 53 of the rotor core 50. In the first axial flow path 53, the cooling oil flows upward while being in contact with the permanent magnet 80. Therefore, the permanent magnet 80 is directly cooled by the cooling oil, and the demagnetization of the permanent magnet 80 due to the high temperature is suppressed. The cooling oil that has reached the upper end of the first axial flow path 53 is introduced into the through hole 98 of the second end plate 96, and is outside the first end plate 90 from the upper end of the through hole 98, that is, outside the rotor 40. Is discharged. At this time, the cooling oil is discharged so as to be sprayed radially outward by the centrifugal force generated by the rotation of the rotor 40. Thereby, the cooling oil is supplied to the stator core 31 and the coil 34 of the stator 30, and the stator 30 is cooled. Thereafter, the cooling oil dripping from the stator 30 is discharged to the outside of the casing 2 through the cooling oil discharge passage 9 of the casing 2. Then, the cooling oil is cooled by the cooling unit 25 while passing through the return flow path 23, and is stored again in the cooling oil storage unit 21.

  As described above, in the rotor 40 of the electric motor 1 of the present embodiment, since the gap 55 is formed in the rotor core 50, the weight of the rotor core 50 can be reduced by the volume of the gap 55. The gap 55 is independent of the first axial flow path 53, the second axial flow path 54, and the radial flow path 92 through which the cooling oil flows, and is in a non-communication state with these. No cooling oil is introduced.

  If the cooling channel in the rotor 40 is communicated with the gap 55, the gap 55 also becomes a part of the cooling channel, so that cooling oil is also introduced into the gap 55. In this case, the cooling oil in the gap 55 of the electric motor 1 also rotates together with the rotor 40, and the moment of inertia during rotational driving increases by the amount of the cooling oil. For this reason, the acceleration / deceleration torque of the electric motor 1 cannot be effectively reduced even though the weight of the rotor core 50 is reduced.

  On the other hand, in the present embodiment, since the gap 55 and the cooling passage of the rotor 40 are isolated from each other, the cooling oil does not flow directly into the gap 55 from the cooling passage. Therefore, it is possible to avoid an unintended increase in the moment of inertia at the time of rotational driving. This suppresses an increase in the acceleration / deceleration torque of the electric motor while supplying only a necessary amount of cooling oil to the portion to be cooled in the rotor core 50. As a result, the performance of the electric motor 1 can be improved.

  In the present embodiment, the gap 55 and the radial flow path 92 are separated by the second steel plate 70 while the gap 55 is defined by the first steel plate 60. Thus, it is possible to prevent the gap 55 and the radial flow path 92 from communicating with each other while securing a large volume of the gap 55. Only by using the two steel plates of the first steel plate 60 and the second steel plate 70, it is possible to obtain the rotor core 50 that achieves both the formation of the gap 55 and the securing of the cooling flow path.

In the present embodiment, the radial channel 92 is formed in the first end plate 90. Thereby, the cooling oil can be introduced into the first axial flow path 53 from the radial inside of the rotor core 50 without eroding the magnetic path in the rotor core 50.
The radial channel 92 is defined by the concave portion 93 of the first end plate 90 and the second steel plate 70. Therefore, the radial flow path 92 can be formed without making a hole in the first end plate 90. Therefore, processing costs can be reduced.

Here, the conventional rotor core having no gap 55 has been manufactured by laminating a plurality of two types of electromagnetic steel plates. The only difference between these electromagnetic steel sheets is that one electromagnetic steel sheet is formed with a convex portion 67 for caulking, and the other electromagnetic steel sheet is formed with a hole portion 77 for caulking. These two types of magnetic steel sheets have been manufactured by press working using two types of corresponding dies.
The difference between the first steel plate 60 and the second steel plate 70 of the present embodiment is only the presence or absence of the hole 65 except for the crimping protrusion 67 and the crimping hole 77. Therefore, in order to manufacture the first steel plate 60 and the second steel plate 70 of the present embodiment, only a change for forming the punched hole 65 is made to only one of the above-mentioned two types of conventional types. Good. Therefore, a manufacturing facility can be easily constructed only by making minor changes to the conventional facility.
If the conventional two types of electromagnetic steel sheets do not have the embedding portion forming holes 62, 72, the first flow passage forming holes 63, 73, the barrier forming holes 64, 74 and the second flow passage forming holes 66, 76, the May be added to the above mold to form them.

In general, the machining cost is increased by the depth of the center hole formed in the shaft 41. In the present embodiment, the region where the shaft center hole 44 extends is up to the vertical position corresponding to the upper end of the rotor core 50. Therefore, the manufacturing cost of the shaft 41 can be reduced. In the present embodiment, even in the shaft center hole 44, the cooling oil is guided downward by the second axial flow path 54, and then the cooling oil flows to the first axial flow path 53 via the radial flow path 92. Can be supplied. Therefore, a sufficient cooling effect of the rotor core 50 can be obtained.
Almost the entire vertical range in which the rotor core 50 is fixed to the shaft 41 has a solid structure, so that the strength at the portion where the shaft 41 supports the rotor core 50 can be ensured.

In this embodiment, since the cooling oil is introduced into the first axial passage 53 after passing through the second axial passage 54 and the radial passage 92, the rotor core 50 reaches the permanent magnet 80. The cooling passage inside is longer. Generally, as the length of the cooling passage in the rotor core 50 that generates heat due to iron loss increases, the cooling oil tends to be heated.
In the present embodiment, since the second axial flow path 54 is covered by the gap 55 from the outside in the radial direction, the gap 55 serves as a magnetic shield for the magnetic field from the outside in the radial direction by the coil 34. Therefore, the arrival of the magnetic field up to the vicinity of the second axial flow path 54 is suppressed. Therefore, heat generation due to iron loss is suppressed in the vicinity of the second axial flow path 54, which is a portion inside the gap 55 in the rotor core 50. Thereby, when cooling oil flows through the second axial flow path 54, heating of the cooling oil is not promoted. Therefore, the cooling effect in the first axial flow path 53 that contributes to cooling the permanent magnet 80 can be maintained high despite the fact that the cooling flow path in the rotor core 50 is long.

<Second embodiment>
A rotor 40A according to the second embodiment will be described with reference to FIG. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.
The rotor 40A of the second embodiment includes a shaft 41A, a rotor core 50A, a first end plate 90A, and a second end plate 96.
The shaft 41A differs from the shaft 41 of the first embodiment in that the shaft center hole 44 and the shaft radial direction hole 45 are not formed. The shaft 41A has a solid structure over the entire area in the direction of the axis O.

  The rotor core 50A differs from the rotor core 50 of the first embodiment in that the second axial flow path 54 is not formed. The rotor core 50A is configured by vertically stacking only a plurality of first steel plates 60A. The first steel plate 60A of the second embodiment is different from the first steel plate 60 of the first embodiment in that the second flow passage forming hole 66 is not formed. The gap 55A of the second embodiment extends over the entire area in the vertical direction of the rotor core 50A, and opens at the upper and lower ends of the rotor core 50A.

  The first end plate 90A of the second embodiment is different from the first end plate 90 of the first embodiment in that a through hole 95A penetrating in a vertical direction is formed instead of the recess 93 in the first end plate 90 of the first embodiment. It is different from the end plate 90. A plurality of through holes 95A of the first end plate 90A are formed at intervals in the circumferential direction so as to correspond to the plurality of first axial flow paths 53.

In the rotor 40A of the second embodiment, the cooling oil is directly supplied to the second end plate 96 from above the rotor 40A. The cooling oil flows through the through hole 98 of the second end plate 96, the first axial flow path 53, and the through hole 95A of the first end plate 90A, and is discharged to the outside of the rotor 40A. In the process of flowing through the first axial flow path 53, the permanent magnet 80 is cooled as in the first embodiment.
In the rotor 40A of the second embodiment, as in the first embodiment, since the first axial flow path 53 is formed independently of the gap 55A, the cooling oil is directly introduced into the gap 55A. There is no.

<Third embodiment>
A rotor 40B according to the third embodiment will be described with reference to FIG. In the third embodiment, the same components as those in the other embodiments are denoted by the same reference numerals, and detailed description is omitted.
The rotor 40B of the third embodiment includes a shaft 41B, a rotor core 50B, a first end plate 90, and a second end plate 96.
A shaft center hole 44B and a shaft radial direction hole 45B different from the shaft center hole 44 and the shaft radial direction hole 45 of the shaft 41 of the first embodiment are formed in the shaft 41B of the third embodiment. The shaft center hole 44B extends from the upper end of the shaft 41B to a vertical position corresponding to the lower end of the rotor core 50B. The shaft radial hole 45 </ b> B extends radially outward from the lower end of the shaft center hole 44 </ b> B and communicates with a radial channel 92 formed in the first end plate 90. In other words, the vertical position of the shaft radial hole 45B is the same as the radial flow path 92. The shaft center hole 44B extends from the upper end of the shaft 41 to a vertical position of the shaft radial hole 45B.
In the present embodiment, the shaft radial hole 45B and the radial flow path 92 are directly connected.

  The rotor core 50B of the third embodiment differs from the rotor core 50 of the first embodiment in that the second axial flow path 54 of the first embodiment is not formed. The rotor core 50B is formed by a plurality of first steel plates 60B and one second steel plate 70B. The first steel plate 60B of the third embodiment is different from the first steel plate 60 of the first embodiment in that the second channel forming hole 66 is not formed. The second steel plate 70B of the third embodiment is different from the second steel plate 70 of the first embodiment in that the second channel forming hole 76 is not formed. The rotor core 50B is configured such that one second steel plate 70B is further stacked below the plurality of first steel plates 60B stacked together.

In the rotor 40B of the third embodiment, similarly to the first embodiment, cooling oil is supplied from above to the shaft center hole 44B of the shaft 41B. The cooling oil flows through the shaft center hole 44B, the shaft radial hole 45B, the radial flow path 92, the first axial flow path 53, and the through hole 98 of the second end plate 96, and is discharged to the outside of the rotor 40B. In the process of flowing through the first axial flow path 53, the permanent magnet 80 is cooled as in the first embodiment.
In the rotor 40B of the third embodiment as well, as in the first embodiment, since the first axial flow path 53 and the radial flow path 92 are formed independently of the gap 55, the cooling oil flows directly into the gap 55. Will not be introduced.

<Fourth embodiment>
A rotor 40C according to a fourth embodiment will be described with reference to FIG. In the fourth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.
The rotor 40C of the fourth embodiment includes a shaft 41C, a rotor core 50C, a first end plate 90C, and a second end plate 96.

  A shaft center hole 44C and a shaft radial direction hole 45C different from the shaft 41 of the first embodiment are formed in the shaft 41C of the fourth embodiment. The shaft center hole 44C extends from the upper end of the shaft 41C to a vertical position between the upper and lower ends of the rotor core 50C. In the present embodiment, the shaft center hole 44C extends to the center of the vertical position of the rotor core 50C. The shaft radial hole 45C extends radially from the lower end of the shaft center hole 44C and opens at the center of the rotor core 50C in the vertical direction.

  The rotor core 50C of the fourth embodiment is different from the rotor core 50 of the first embodiment in that a second axial flow path 54 is not formed and a radial flow path 57C is formed. The radial flow path 57C of the rotor core 50C is formed at the center of the vertical position of the rotor core 50C. The radial flow path 57C has a radially inner end communicating with the shaft radial hole 45C, and a radially outer end communicating with the first axial flow path 53. In the present embodiment, voids 55C are formed on both upper and lower sides of the radial flow path 57C.

  The rotor core 50C is configured by stacking a first steel plate 60C, a second steel plate 70C, and a third steel plate 78C. The first steel plate 60C of the fourth embodiment is different from the first steel plate 60 of the first embodiment in that the second channel forming hole 66 is not formed. The second steel plate 70C of the fourth embodiment is different from the second steel plate 70 of the first embodiment in that the second flow passage forming hole 76 is not formed.

  The upper part of the radial flow path 57C in the rotor core 50C is configured by laminating a plurality of first steel plates 60C and further laminating one second steel plate 70C below. The lower part of the radial flow path 57C in the rotor core 50C is configured by stacking a plurality of first steel plates 60C and further stacking one second steel plate 70C from above. The third steel plate 78C is provided so as to be sandwiched between an upper portion and a lower portion of the rotor core 50C. The third steel plate 78C is formed so that a slit (not shown) penetrating in the vertical direction extends in the radial direction. The radially inner end of the slit communicates with the shaft radial hole 45C. The radially outer end of the slit is formed at a position communicating with the first axial flow path 53. The shape of the slit as viewed in the direction of the axis O may be, for example, the same as the shape of the concave portion 93 shown in FIG. 8, that is, a V-shape whose apex faces radially inward. The third steel plate 78C is sandwiched between the pair of second steel plates 70C, 70C from above and below, so that the pair of second steel plates 70C, 70C and the slit define a radial channel 57C. The radial channel 57C is separated from the gap 55C by a pair of upper and lower second steel plates 70C, 70C.

  The first end plate 90C of the fourth embodiment is different from the first end plate 90 of the first embodiment in that a through hole 95C penetrating in a vertical direction is formed instead of the concave portion 93 in the first end plate 90 of the first embodiment. It is different from the end plate 90. A plurality of through-holes 95C of the first end plate 90C are formed at intervals in the circumferential direction so as to correspond to the plurality of first axial flow paths 53.

In the rotor 40C of the fourth embodiment, similarly to the first embodiment, cooling oil is supplied to the shaft center hole 44C from above. The cooling oil reaches the center of the first axial flow path 53 in the vertical direction via the shaft center hole 44C, the shaft radial hole 45C, and the radial flow path 57C. The cooling oil branches and flows upward and downward in the first axial flow path 53 at the communication point between the radial flow path 57C and the first axial flow path 53. The cooling oil flowing upward in the first axial flow path 53 passes through the through hole 98 of the second end plate 96 and is discharged to the outside of the rotor 40C. The cooling oil flowing downward in the first axial flow path 53 is discharged to the outside of the rotor 40C through the through hole 95C of the first end plate 90C.
In the rotor 40C of the fourth embodiment, since the first axial flow path 53 and the radial flow path 57C are formed independently of the upper and lower gaps 55C, 55C, cooling oil is supplied to these gaps 55C, 55C. It is not introduced directly.

<Fifth embodiment>
A rotor 40D according to a fifth embodiment will be described with reference to FIG. In the fifth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.
The rotor 40D of the fifth embodiment includes a shaft 41, a rotor core 50D, a first end plate 90D, and a second end plate 96D.

The rotor core 50D of the fifth embodiment differs from the rotor core 50 of the first embodiment in that the second axial flow path 54 of the first embodiment is not formed. The rotor core 50D is formed by a plurality of first steel plates 60D and one second steel plate 70D. The first steel plate 60D of the fifth embodiment is different from the first steel plate 60 of the first embodiment in that the second channel forming hole 66 is not formed. The second steel plate 70D of the fifth embodiment is different from the second steel plate 70 of the first embodiment in that the second channel forming hole 76 is not formed. The rotor core 50D is configured such that one second steel plate 70D is further stacked above the plurality of first steel plates 60D stacked together.
The upper end of the gap 55D of the fifth embodiment is closed by the second steel plate 70D, and the lower end is closed by the first end plate 90D.

  The first end plate 90D of the fifth embodiment is different from the first end plate 90D of the first embodiment in that a through hole 95D that penetrates in a vertical direction is formed instead of the recess 93 in the first end plate 90 of the first embodiment. It is different from the end plate 90. A plurality of through holes 95D of the first end plate 90D are formed at intervals in the circumferential direction so as to correspond to the plurality of first axial flow paths 53.

  The second end plate 96D of the fifth embodiment is different from the second end plate 96 of the first embodiment in that the through-hole 98 of the second end plate 96 of the first embodiment is not formed and the recess 99D is formed. It is different from the plate 96. The concave portion 99D is formed so as to be depressed upward from a surface facing downward of the second end plate 96. The concave portion 99D has a vertically symmetric shape with the concave portion 93 of the first end plate 90 in the first embodiment. Since the second end plate 96D is further laminated on the second steel plate 70D laminated on the uppermost part of the rotor core 50D, the radial flow path 57D is defined by the concave portion 99D of the second end plate 96D and the second steel plate 70D. Have been. A radially inner end of the radial flow path 57 </ b> D communicates with the shaft radial hole 45. That is, the radial channel 57D is directly connected to the shaft radial hole 45. The radially outer end of the radial flow path 57 </ b> D communicates with the upper end of the first axial flow path 53.

In the rotor 40D of the fifth embodiment, similarly to the first embodiment, cooling oil is supplied to the shaft center hole 44 from above. The cooling oil reaches the upper end of the first axial flow path 53 via the shaft center hole 44, the shaft radial hole 45, and the radial flow path 57D. The cooling oil cools the permanent magnet 80 in the process of flowing downward in the first axial flow path 53, and is discharged to the outside of the rotor 40D through the through hole 95D of the first end plate 90D.
Also in the rotor 40D of the fifth embodiment, the radial flow path 57D of the second end plate 96D and the first axial flow path 53 of the rotor core 50 are formed independently of the gap 55D. It is not directly introduced into 55D.

<Sixth embodiment>
A motor according to a sixth embodiment will be described with reference to FIG. In the sixth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.
The motor 1 of the first embodiment is a so-called vertical motor 1 in which the axis O serving as the center of rotation is vertically aligned, whereas the motor 1E of the sixth embodiment has the axis O serving as the center of rotation horizontally. It is a so-called horizontal motor that matches the direction. The horizontally placed electric motor 1E is provided as a traveling motor on a construction machine such as a wheel loader.

The electric motor 1E of the sixth embodiment has the same stator 30 and rotor 40 as the first embodiment. The stator 30 and the rotor 40 differ from the first embodiment only in the posture. That is, the stator 30 and the rotor 40 are arranged with the axis O aligned in the horizontal direction.
The casing 2E surrounding the stator 30 and the rotor 40 has a cylindrical portion 3E extending in the horizontal direction along the axis O and having a housing space inside, and a housing space on one side in the horizontal direction (one side in the axial direction). ), And a second lid 7 for closing the housing space from the other side in the horizontal direction (the other side in the axial direction).

In the upper wall portion of the cylindrical portion 3E, a cooling oil introduction passage 16 that opens upward to the outside of the cylindrical portion 3E and that opens to the upper portion of the inner peripheral surface of the cylindrical portion 3E is formed. . A pair of openings on the inner peripheral surface of the cylindrical portion 3E in the cooling oil introduction passage 16 are formed at positions corresponding to the coil ends on both axial sides of the coil 34.
In a lower wall portion of the cylindrical portion 3E, there is formed a cooling oil discharge passage 17 which opens downward to the outside of the cylindrical portion 3E and opens at a lower portion of the inner peripheral surface of the cylindrical portion 3E. . A pair of openings at the inner peripheral surface of the cylindrical portion 3E in the cooling oil discharge passage 17 are formed at positions corresponding to the coil ends on both sides in the direction of the axis O of the coil 34.

  The introduction flow path 22E of the cooling oil supply section 20E has an upstream end connected to the cooling oil storage section 21 and a downstream side branched into two, and the cooling oil introduction hole 6 and the cooling oil introduction path 16 of the casing 2E respectively. It is connected to the. A cooling oil pump 24 is provided in the introduction channel 22E. The upstream end of the recirculation flow path 23E of the cooling oil supply section 20E is connected to the cooling oil discharge path 17 of the casing 2E, and the downstream end is connected to the cooling oil storage section 21. A cooling unit 25 is provided in the reflux channel 23E.

When the cooling oil pump 24 of the cooling oil supply unit 20E operates, the cooling oil of the cooling oil storage unit 21 is supplied to the cooling oil introduction hole 6 and the cooling oil introduction path 16 of the casing 2E of the electric motor 1E via the introduction flow path 22E. You.
The cooling oil introduced into the cooling oil introduction hole 6 is introduced into the shaft center hole 44 from one end in the horizontal direction of the shaft 41 of the rotor 40 that is rotationally driven, and the rotor core 50 and the rotor core 50 are provided as in the first embodiment. The permanent magnet 80 provided in the cooling unit 50 is cooled and discharged to the outside of the rotor 40.
The cooling oil introduced into the cooling oil introduction passage 16 is directly supplied to the coil end of the coil 34 to cool the coil end. Thereafter, the cooling oil is dripped downward to cool the outer surface of the rotor 40, is introduced into the cooling oil discharge passage 17 together with the cooling oil flowing in the rotor 40, and is discharged outside the casing 2 </ b> E.

  As described above, even when the electric motor 1E is arranged horizontally, the cooling oil is directly introduced into the gap 55 because the gap 55 is independent of the cooling flow path in the rotor 40. Never. Therefore, similarly to the first embodiment, the performance of the electric motor 1E can be improved.

<Other embodiments>
The embodiments of the present invention have been described above, but the present invention is not limited thereto, and can be appropriately changed without departing from the technical idea of the present invention.

  In the first embodiment, communication between the gap 55 and the radial flow path 92 is avoided by making the positions in the direction of the axis O different, but the gap 55 and the radial flow path 92 are shifted in the circumferential direction. The arrangement may be such that mutual communication is avoided by arranging as described above. That is, a configuration in which a plurality of voids are formed at intervals in the circumferential direction, and a radial flow path is formed between the voids adjacent to each other. Thus, the gap and the radial flow path can be arranged at the same position in the direction of the axis O while avoiding mutual communication.

In the first embodiment, the number of poles of the rotor 40 is eight, but may be changed as appropriate. The shaft radial holes 45 and the second axial flow passages 54 are arranged at equal intervals in the circumferential direction, but may be appropriately changed. It is preferable that half of the number of poles of the rotor 40 be formed at equal intervals in the circumferential direction of the shaft radial hole 45 and the second axial flow path 54.
In the first embodiment, eight radial flow paths 92 are formed when viewed in the direction of the axis O, but may be changed as appropriate. The number of the radial passages 92 is preferably set to be twice the number of the shaft radial holes 45 and the second axial passages 54, that is, preferably equal to the number of poles of the rotor 40.

  In the first embodiment, the cooling oil flowing inside the rotor 40 is sprayed to the stator 30, but a cooling path for cooling the stator 30 may be provided separately from the cooling path inside the rotor 40. The cooling oil may be directly supplied to the stator 30 from the outside.

In the first embodiment, the magnet embedded portion 52 and the first axial flow path 53 are integrally formed so as to be continuous, but they may be formed separately. In this case, the magnet embedded portion 52 and the first axial flow path 53 are close to each other as viewed in the direction of the axis O so that the permanent magnet 80 can be effectively cooled by the cooling oil flowing through the first axial flow path 53. It is preferable to form them. In order for the permanent magnet 80 to be cooled by the cooling oil flowing through the first axial channel 53, the gap 55 is formed at a radial position between the first axial channel 53 and the permanent magnet 80. Rather, it is preferable that it is formed radially inward of both the first axial flow path 53 and the permanent magnet 80.
In the first embodiment, in addition to the flux barrier portion 56, the first axial flow path 53 also has a function as a flux barrier. When the magnet embedded portion 52 and the first axial flow path 53 are formed separately, in addition to the flux barrier portion 56 of the first embodiment, a second flux barrier portion is provided in the first axial direction of the first embodiment. It is preferable to provide it at the location where the directional channel 53 is formed.

  In the first embodiment, the second axial channel 54 extends along the outer peripheral surface of the shaft 41. The second axial flow path 54 may be formed inside the rotor core 50 without contacting the outer peripheral surface of the shaft 41. Even in this case, the second axial flow path 54 is preferably provided on the inner peripheral side of the gap so as to be surrounded from the outer peripheral side by the gap.

In the first embodiment, a radial passage 92 is defined by the concave portion 93 of the first end plate 90 and the second steel plate 70, and the radial passage 92 is formed on the surface of the first end plate 90. Was explained. The present invention is not limited to this, and the radial flow path 92 may be formed inside the first end plate 90.
In addition to the radial flow path 92 of the first end plate 90, another radial flow path communicating with the first axial flow path 53 may be formed in the rotor core 50 or the second end plate 96. That is, the radial flow path may be formed in at least one of the first end plate 90, the second end plate 96, and the rotor core 50.

In the first embodiment, an example in which only one second steel plate 70 is provided has been described, but a configuration in which a plurality of second steel plates 70 are stacked on each other may be employed.
In the fourth embodiment, an example in which only one third steel plate 78C is provided has been described. However, a plurality of third steel plates 78C may be stacked on each other in order to secure a flow path cross-sectional area of the radial flow path 57C. .
The permanent magnets 80 may be provided not only so as to be embedded inside the rotor core 50 but also on the outer peripheral surface of the rotor core 50 at intervals in the circumferential direction.
The shaft center hole 44 extends below the vertical position corresponding to the upper end of the rotor core 50, and the shaft center hole 44 communicates with the second axial flow path 54 via a shaft radial hole 45 connected to the lower end. It may be configured.

  The shaft center hole 44 may extend below the vertical position of the shaft radial hole 45. When the shaft center hole 44 is formed by drilling, the lower end of the shaft center hole 44 has a conical shape. Only such a conical shape may protrude downward from the shaft radial hole 45. This aspect is also included in an aspect in which the shaft radial direction hole 45 is connected to the lower end of the shaft center hole 44.

The first end plate 90 and the second end plate 96 are not limited to the shapes of the first embodiment, and may have other shapes than the plate shape.
In the first embodiment, an example in which the first steel plate 60 is provided with a so-called V-shaped caulking as the caulking convex portion 67 has been described. However, another caulking shape such as a round caulking may be used. The caulking hole 77 of the second steel plate 70 may have any shape as long as the caulking protrusion 67 of the first steel plate 60 can be fitted.
The shape of each hole formed in the first steel plate 60 and the second steel plate 70 may be appropriately changed.

  The above modification may be applied to the vertical type of the second to fifth embodiments, or may be applied to the horizontal type of the sixth embodiment. The rotor 40 of the second to fifth embodiments may be applied to the sixth embodiment to be of a horizontal type.

In the first to fifth embodiments, the axis O is aligned vertically, and in the sixth embodiment, the axis O is aligned horizontally, but the axis O may be aligned obliquely.
Although the example in which the output of the electric motor 1 is transmitted to the swing pinion 123 has been described, for example, the electric motor 1 may be connected to the swing pinion 123 via a planetary gear reducer.
The electric motor 1 may be connected to the engine 136 or the hydraulic pump 138 via the PTO. Thus, the engine 136 can be assisted when the hydraulic pump 138 is driven.
In the embodiment, the example in which the electric motor is applied to the hydraulic shovel 100 and the wheel loader as the construction machine has been described, but the electric motor of the present embodiment may be applied to other construction machines.

1, 1E: electric motor, 2, 2E: casing, 3, 3E: cylindrical portion, 4: first lid portion, 5: shaft housing portion, 6: cooling oil introduction hole, 7: second lid portion, 8: shaft Penetration part, 9 ... cooling oil discharge path, 11 ... first bearing, 12 ... second bearing, 13 ... first seal part, 14 ... second seal part, 16 ... cooling oil introduction path, 17 ... cooling oil discharge path, 20, 20E: cooling oil supply section, 21: cooling oil storage section, 22, 22E: introduction flow path, 23, 23E: return flow path, 24: cooling oil pump, 25: cooling section, 30: stator, 31: stator core 32, yoke, 33, teeth, 34, coil, 40, 40A, 40B, 40C, 40D, rotor, 41, 41A, 41B, 41C, shaft, 42, stepped part, 43, fixed surface, 44, 44B, 44C ... Shaft center hole, 45, 45B, 45C ... Shaft Directional holes, 50, 50A, 50B, 50C, 50D: rotor core, 51: core central hole, 52: magnet embedded portion, 53: first axial flow path, 54: second axial flow path, 55, 55A, 55C, 55D: void portion, 56: flux barrier portion, 57, 57C, 57D: radial flow path, 60, 60A, 60B, 60C, 60D: first steel plate, 61: steel plate central hole, 62: embedded portion formation Hole 63, first flow path forming hole, 64 barrier forming hole, 65 drawing hole, 66 second flow path forming hole 67 convex portion for caulking, 70, 70B, 70C, 70D second steel plate 71 ... Steel plate central hole, 72 ... Embedded part forming hole, 73 ... First passage forming hole, 74 ... Barrier forming hole, 76 ... Second passage forming hole, 77 ... Crimping hole, 78C ... Third steel plate, 80 ... permanent magnet, 90, 90A, 90C, 90D ... first end plate End plate), 91: circular hole, 92: radial flow path, 93: concave part, 94: radial flow path forming part, 95A, 95C, 95D: through hole, 96, 96D: second end plate (end plate) , 97: circular hole, 98: through hole, 99D: concave portion, 100: hydraulic excavator, 110: lower traveling body, 111: crawler belt, 120: swing circle, 121: outer race, 122: inner race, 123: swing pinion, 130: upper revolving unit, 131: cab, 132: working machine, 133: boom, 134: arm, 135: bucket, 136: engine, 137: generator motor, 138: hydraulic pump, 139: inverter, 140: capacitor, L: turning axis, O: axis

Claims (8)

A shaft extending along an axis;
A rotor core having a plurality of steel plates stacked in the axial direction and fixed to a radially outer side of the shaft,
A permanent magnet fixed to the rotor core, and a plurality of permanent magnets are arranged at intervals in a circumferential direction of the shaft;
A pair of end plates provided so as to sandwich the rotor core from both sides in the axial direction,
With
The rotor core,
A first axial flow path that extends in the axial direction and through which the cooling oil flows,
Along with communicating with the first axial flow path, a second axial flow path extending in the axial direction inside the radial direction of the first axial flow path,
Wherein independently of the first axial passage and said second axial passage, the first axial passage and the radially inner than the permanent magnet and the diameter than the second axial flow path And a gap formed so as to cover the second axial flow path from the radial outside ,
A rotor having: Said shaft,
A shaft center hole extending from one end of the shaft in the axial direction toward the other end in the axial direction;
A shaft radial hole extending radially from the shaft center hole to the outer peripheral surface of the shaft;
Has,
At least one of the end plate and the rotor core,
2. The rotor according to claim 1, wherein the rotor extends in the radial direction independently of the gap, and has a radial flow passage communicating with the first axial flow passage and the shaft radial hole. 3. As the steel sheet,
A first flow path forming hole penetrating in the axial direction, having a second flow path forming hole and a hole, a plurality of first steel plates stacked on each other in the axial direction,
A second steel plate having a first flow path forming hole and a second flow path forming hole penetrating in the axial direction, and further stacked from the axial direction on a plurality of first steel sheets stacked on each other,
Has,
The first axial flow path is defined by the first flow path forming holes of the first steel sheet and the second steel sheet,
The second axial flow path is defined by the second flow path forming holes of the first steel sheet and the second steel sheet,
The void portion is defined by the hole of the first steel plate,
The rotor according to claim 2, wherein the second steel plate separates the gap from the radial flow path. An end plate of the pair of end plates that is in contact with the second steel plate is provided with a concave portion that is depressed from the second steel plate side,
The rotor according to claim 3, wherein the radial flow path is defined by the concave portion and the second steel plate. The first steel plate is provided with a caulking projection projecting in the axial direction,
The second steel plate is provided with a caulking hole penetrating in the axial direction,
The plurality of first steel plates are stacked on each other by the caulking convex portions being sequentially fitted,
5. The rotor according to claim 3, wherein the second steel plate is stacked on the first steel plate by fitting a caulking projection of the first steel plate into the caulking hole.   The rotor according to any one of claims 2 to 5, wherein the shaft center hole extends to an axial position corresponding to an end of the rotor core on one side in the axial direction. Rotor according to prior Ki径direction channel is any one of said second axial flow passage from claim 2 in communication with the shaft radial holes through 6. A shaft extending along an axis, a rotor core fixed radially outward of the shaft, a plurality of permanent magnets arranged in the rotor core at intervals in a circumferential direction of the shaft, and the rotor core from both sides in the axial direction. A rotor having a pair of end plates provided so as to sandwich it,
A stator core surrounding the rotor from the outer peripheral side, and a stator having a plurality of coils fixed to the stator core and arranged at intervals in the circumferential direction with respect to each other;
With
The shaft is
A shaft center hole extending from the one axial end of the shaft to the axial position corresponding to the one axial end of the rotor core;
A shaft radial hole extending from the shaft center hole to the outer peripheral surface of the shaft;
Has,
The rotor core,
A first flow path forming hole penetrating in the axial direction, a punched hole, and a plurality of first steel sheets having a second flow path forming hole and stacked on each other in the axial direction,
A first flow path forming hole penetrating in the axial direction, and a second flow path forming hole, at least one second steel sheet further stacked from the other side in the axial direction on a plurality of first steel sheets stacked on each other When,
Has,
A first axial flow path extending in the axial direction along the permanent magnet is defined by the first flow path forming holes of the first steel sheet and the second steel sheet,
By the hole of the first steel plate, a gap located radially inward of the first axial flow path is defined independently of the first axial flow path, and the lower end of the gap has a lower end. Closed by the second steel plate,
A second passage extending in the axial direction inside the gap in the radial direction and communicating with the shaft radial hole at the upper end by the second channel forming holes of the first steel plate and the second steel plate and the outer peripheral surface of the shaft. A biaxial flow path is defined,
The gap is formed so as to cover the second axial flow path from the radial outside,
The end plate on the other side in the axial direction of the pair of end plates has a concave portion recessed from a surface facing one side in the axial direction,
The concave portion and the second steel plate define a radial channel that extends in the radial direction and communicates a lower end of the first axial channel and a lower end of the second axial channel,
The end plate on the one side in the axial direction of the pair of end plates has a through hole penetrating in the axial direction and connected to the first axial flow path, and the gap portion is formed on one side in the axial direction. Motor that is blocked from the motor.

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