JP2018170943A - Rotor, electric motor and hydraulic shovel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor capable of improving the performance of an electric motor.SOLUTION: A rotor includes a rotor core 50 in which multiple magnet embedding holes 53 penetrating in the axis O direction are formed at intervals in the hoop direction, multiple permanent magnets 80 provided in respective magnet embedding holes 53, and sectioning the space in the magnet embedding hole 53 into the inner space 61 and an outer space 62 extending in the axis O direction on the radial outside of the inner space 61, a first end plate 90 having a distribution path 92 for supplying cooling medium supplied externally only to the inner space 61, out of the inner space 61 and the outer space 62, and a second end plate 96 having an exhaust passage 98 for draining the cooling medium, circulated through the inner space 61, to the outside. The first end plate 90 and the second end plate 96 form a first exhaust port 62a and a second exhaust port 62b for making the end of the outer space 62 in the axis O direction communicate with the outside.SELECTED DRAWING: Figure 4

Description

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

  Patent Document 1 discloses an electric motor used in a work machine such as a hydraulic excavator. The rotor core of the electric motor has a laminated steel plate structure in which a large number of steel plates are laminated. A plurality of magnet embedded holes are formed in the rotor core at intervals in the circumferential direction, and permanent magnets are embedded in each magnet embedded hole.

  Spaces as flux barriers are formed at both circumferential ends of each permanent magnet. One of these spaces is an inner space disposed closer to the radially inner side, and the other is an outer space disposed closer to the radially outer side. The inner space is used as a flow path through which cooling oil flows.

  The rotor core is sandwiched between a pair of end plates from the stacking direction of the steel plates. One end plate is formed with a flow path for supplying cooling oil to the inner space, and the other end plate is formed with a flow path for discharging the cooling oil flowing through the inner space to the outside of the rotor core. .

JP 2007-20337 A

By the way, in the said electric motor, a part of cooling oil which distribute | circulates inner side space may ooze out to outer side space through the clearance gap between a rotor core and a permanent magnet, and the clearance gap between steel plates. When the oozed cooling medium stays in the outer space, the cooling medium absorbs heat and becomes high temperature, thereby causing thermal demagnetization of the permanent magnet and lowering the performance of the electric motor.
This invention is made | formed in view of such a subject, Comprising: It aims at providing the rotor which can maintain the performance of an electric motor, the electric motor provided with the same, and a hydraulic shovel.

  The rotor according to the first aspect of the present invention includes a shaft extending in the axial direction and a plurality of steel plates stacked in the axial direction, and is fixed to the radial outer side of the shaft and penetrates in the axial direction. A plurality of magnet embedded holes formed in the circumferential direction with a plurality of spaced apart magnet cores, and provided in each of the magnet embedded holes, and the space in the magnet embedded holes is made larger than the inner space and the inner space. A plurality of permanent magnets partitioned into an outer space extending in the axial direction on the outer side in the radial direction, and a cooling medium supplied from the outside provided so as to abut on the end surface on the one axial direction side of the rotor core, A first end plate having a distribution path for supplying only the inner space of the inner space and the outer space, and an end surface of the rotor core on the other side in the axial direction; A second end plate having a discharge path for discharging the cooling medium flowing through the outside, wherein at least one of the first end plate and the second end plate is an end in the axial direction of the outer space. A discharge port is formed to communicate the part to the outside.

  According to the above aspect, the performance of the electric motor can be maintained.

1 is a side view of a hydraulic excavator provided with an electric motor according to a first embodiment of the present invention. 1 is a plan view of a hydraulic excavator provided with an electric motor according to 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 of the rotor of the electric motor concerning a first embodiment of the present invention. It is VV sectional drawing of FIG. FIG. 6 is a partially enlarged view of FIG. 5. It is VII-VII sectional drawing of FIG. It is VIII-VIII sectional drawing of FIG. It is typical sectional drawing which shows a part of rotor of the electric motor which concerns on the 1st modification of 1st embodiment of this invention. It is typical sectional drawing which shows a part of rotor of the electric motor which concerns on the 2nd modification of 1st embodiment of this invention. It is typical sectional drawing which shows a part of rotor of the electric motor which concerns on the 3rd modification of 1st embodiment of this invention. It is typical sectional drawing which shows a part of rotor of the electric motor which concerns on the 4th modification of 1st embodiment of this invention. It is a typical longitudinal section showing a part of rotor of an electric motor concerning a second embodiment of the present invention. It is sectional drawing orthogonal to the axis line of the 1st end plate of the electric motor which concerns on 3rd embodiment of this invention.

<First embodiment>
Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS.

<Work machine>
As shown in FIGS. 1 and 2, a hydraulic excavator 100 as a work machine includes a lower traveling body 110, a swing circle 120, and an upper swing body 130. Hereinafter, the direction in which gravity acts in a state where the work machine is installed on a horizontal plane is referred to as “vertical direction”.
The lower traveling body 110 has a pair of left and right crawler belts 111 and 111, and the crawler belts 111 and 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 body 110 and the upper swing body 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 centering on the turning axis L extending in the vertical direction. The inner race 122 is an annular member that is 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 turning axis L. The swing pinion 123 meshes with the inner teeth of the inner race 122, and the inner race 122 rotates relative to the outer race 121 as the swing pinion 123 rotates.

  The upper turning body 130 is supported by the inner race 122 so as to be turnable around the turning axis L with respect to the lower traveling body 110. The upper swing body 130 includes a cab 131, a work machine 132, an engine 136 provided behind them, 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 arranged on the front left side of the upper swing body 130 and is provided with a driver's driver's seat. The work implement 132 is provided so as to extend in front of the upper swing body 130, and includes 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 engine 136 and the generator motor 137 are spline-coupled to each other. The generator motor 137 is driven by the engine 136 to generate electric power. 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 through an inverter 139.
The electric motor 1 is arranged in a vertically placed state in which the axis O serving as the rotation center coincides with the vertical direction. The output of the electric motor 1 is transmitted to the swing pinion 123 that meshes with the inner teeth of the inner race 122.

The 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.
When the turning of the upper swing body 130 is decelerated, the electric motor 1 functions as a generator to generate electric power as regenerative energy. This electric 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. The generator motor 137 is driven by the electric power of the capacitor, so that 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 that has a cylindrical shape that extends in the vertical direction (axis O direction) and has an inner space as a housing space, and a first lid portion 4 and a second lid portion 7 that block the housing space from above and below. Have.

  In the center of the first lid portion 4, a shaft housing portion 5 that protrudes upward (the other side in the axis O direction) 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 passing through the shaft housing portion 5 along the axis O. A first bearing 11 having an annular shape centering on 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.

  A shaft penetrating portion 8 is formed in the center of the second lid portion 7 so as to extend downward in a cylindrical shape toward the lower side (one side in the axis O direction) and to allow the accommodation space and the external space to communicate with each other vertically. A second bearing 12 having an annular shape centering on 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 penetrating portion 8. The second lid portion 7 is formed with a cooling oil discharge passage 9 for discharging the cooling oil in the storage space to the outside by communicating the storage space with the outside.

<Cooling oil supply unit>
The cooling oil supply unit 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 again into the casing 2. That is, the cooling oil is circulated by the cooling oil supply unit 20.
The cooling oil supply unit 20 includes a cooling oil storage unit 21, an introduction channel 22, a reflux channel 23, a cooling oil pump 24, and a cooling unit 25.

  The cooling oil storage unit 21 stores cooling oil. The introduction channel 22 has an upstream end connected to the cooling oil reservoir 21 and a downstream end connected to the cooling oil introduction hole 6 in the casing 2 from the outside. The reflux channel 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 reservoir 21. The cooling oil pump 24 is provided in the introduction flow path 22 and pumps the cooling oil in the cooling oil reservoir 21 to the cooling oil introduction hole 6 of the casing 2 through the introduction flow path 22. The cooling unit 25 is provided in the recirculation flow path 23 and cools the cooling oil discharged from the cooling oil discharge path 9 of the casing 2 and flowing through the recirculation flow path 23. The cooling unit 25 cools the cooling oil, for example, by exchanging heat between air from the outside 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 with the axis O as the center, and a yoke 32 whose outer peripheral surface is fixed to the inner peripheral surface of the casing 2, and in the circumferential direction of the yoke 32 so as to protrude 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 plates in the vertical direction.

  A plurality of coils 34 are provided so as to correspond to the teeth 33, and are wound around the teeth 33. Thus, a plurality of coils 34 are provided at intervals in the circumferential direction. A portion of each coil 34 that protrudes upward from the stator core 31 is an upper coil end 34a. A portion of each coil 34 that protrudes downward from the stator core 31 is a lower coil end 34b. As the winding constituting the coil 34, for example, a rectangular winding having a quadrangular cross section is employed.

<Rotor>
As shown in FIGS. 3 and 4, the rotor 40 includes a shaft 41, a rotor core 50, a permanent magnet 80, a first end plate 90, a second end plate 96, and an axial force applying unit 70.

<Shaft>
The shaft 41 is a rod-shaped member that extends along the axis O. Hereinafter, the radial direction with respect to the axis O of the shaft 41 is simply referred to as “radial direction”, and the circumferential direction with respect to the axis O of the shaft 41 is simply referred to as “circumferential direction”.
The shaft 41 is disposed in the casing 2 so as to penetrate the inside of the stator 30 in the vertical direction. The upper end of the shaft 41 extends into the shaft housing portion 5 in the casing 2. The lower end of the shaft 41 extends through the shaft through portion 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 rotatable relative to the casing 2 around the axis O. 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 ensured.

A shaft center hole 44 extending downward from the upper end of the shaft 41 and a shaft radial hole 45 from the shaft center hole 44 to the outer peripheral surface of the shaft 41 are formed in the shaft 41.
The shaft center hole 44 does not extend over the entire vertical direction of the shaft 41, but extends midway from the upper end to the lower end of the shaft 41. As a result, the shaft 41 has a hollow structure in the portion where the shaft center hole 44 is formed from the upper end toward the lower end, and the remaining lower portion has a solid structure.

The shaft radial hole 45 extends in the radial direction so that the extending direction coincides with the direction orthogonal to the axis O. The radially inner end of the shaft radial hole 45 communicates with the lower end of the shaft center hole 44. In other words, the shaft center hole 44 extends only to the vertical position of 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 opens to the upper end of the fixed surface 43 on the outer peripheral surface of the shaft 41. The rotor core 50 is fitted on the fixed surface 43. The fixed surface 43 is a predetermined region from the opening of the shaft radial hole 45 downward. A plurality of shaft radial holes 45 are formed at intervals in the circumferential direction. In the present embodiment, a total of four shaft radial holes 45 are formed radially with an interval of 90 ° in the circumferential direction.

<Rotor core>
As shown in FIGS. 3 and 4, the outer shape of the rotor core 50 has a cylindrical shape with the axis O as the center, and is externally fitted to the fixed surface 43 on the outer peripheral surface of the shaft 41. An upper end surface 50 c of the rotor core 50 that is fitted on the shaft 41 is a vertical position corresponding to the lower end of the shaft center hole 44. The shaft center hole 44 extends from the upper end of the shaft toward the lower end to the vertical position corresponding to the upper end surface 50 c of the rotor core 50. The shaft radial hole 45 is also located at a vertical position corresponding to the upper end surface 50 c of the rotor core 50. The outer peripheral surface 50a of the rotor core 50 has a cylindrical surface shape with the axis O as the center. The rotor core 50 is configured by laminating a plurality of steel plates (electromagnetic steel plates) in the vertical direction. The plurality of steel plates have the same shape as each other.

As shown in FIGS. 3 to 5, a core center hole 51, an axial flow path 52, and a magnet embedded hole 53 are formed in the rotor core 50.
The core center hole 51 is a hole formed in the center of the rotor core over the vertical direction of the rotor core 50. The core central hole 51 has a circular cross section perpendicular to the axis O. The rotor core 50 is fitted on the fixed surface 43 of the shaft 41 through the core center hole 51.

  A plurality of the axial flow paths 52 are formed in the inner peripheral side portion of the rotor core 50 at intervals in the circumferential direction. The axial flow path 52 extends in a uniform shape over the entire vertical direction of the rotor core 50. The axial flow path 52 is open to the lower end surface 50 b and the upper end surface 50 c of the rotor core 50. In the present embodiment, the axial flow path 52 is formed so as to be in contact with the fixed surface 43 on the outer peripheral surface of the shaft 41. The upper end of the axial flow path 52 communicates with the radially outer end of the shaft radial hole 45. The shaft radial hole 45 is located at a vertical position connected to the upper end of the axial flow path 52.

  As shown in FIG. 5, a plurality of magnet embedding holes 53 are formed in the radially outer portion of the rotor core 50 at intervals in the circumferential direction. The magnet embedding hole 53 extends in a uniform shape over the entire vertical direction of the rotor core 50. The magnet embedding hole 53 opens in the lower end surface 50b and the upper end surface 50c of the rotor core 50.

  The magnet embedding hole 53 has a long hole shape extending in the circumferential direction and in the radial direction when viewed in the direction of the axis O, that is, a long hole shape extending obliquely with respect to the radial direction. The plurality of magnet embedding holes 53 are arranged so as to form a V shape in which each pair of magnet embedding holes 53 and 53 protrudes radially inward. The vertex side of the V-shape of each set is the end portion on the radially inner side of each magnet embedding hole 53. The V-shaped opening side of each set is an end portion on the radially outer side of each magnet embedding hole 53. In each of the embodiments, a total of eight sets each having a V shape are provided at equal intervals in the circumferential direction.

Specifically, as shown in FIG. 6, each magnet embedding hole 53 is partitioned by a pair of magnet fixing walls 54, 55, an inner space forming wall 56 and an outer space forming wall 57. 3 and 4, the outer space forming wall 57 and the inner space forming wall 56 are not actually present in the same vertical cross section, but are virtually present in the same vertical cross section for explanation. Shown as a thing.
The pair of magnet fixing walls 54 and 55 extend in the longitudinal direction of the magnet embedding hole 53 as viewed in the direction of the axis O. The pair of magnet fixing walls 54 and 55 are parallel to each other and face each other.

The inner space forming wall 56 connects the radially inner ends of the pair of magnet fixing walls 54 and 55 as viewed in the direction of the axis O. The inner space forming wall 56 is formed so as to be recessed toward the radially inner side in the radial direction with respect to the pair of magnet fixing walls 54 and 55 as viewed in the direction of the axis O.
The outer space forming wall 57 connects the radially outer ends of the pair of magnet fixing walls 54 and 55 as viewed in the direction of the axis O. The inner space forming wall 56 is formed so as to be recessed outward in the radial direction from the magnet fixing walls 54 and 55 as viewed in the direction of the axis O.

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

  In the present embodiment, each permanent magnet 80 is disposed in the magnet embedding hole 53 and is fixed to the rotor core 50 in the magnet embedding hole 53. As shown in FIGS. 5 and 6, the permanent magnet 80 has a rectangular cross section perpendicular to the axis O. A pair of end surfaces 80 a and 80 b in the direction of the axis O of the permanent magnet 80 are flush with the lower end surface 50 b and the upper end surface 50 c of the rotor core 50. That is, the positions of the end surfaces 80a and 80b of the permanent magnet 80 and the lower end surface 50b and upper end surface 50c of the rotor core 50 in the direction of the axis O are the same. Of the side surfaces connecting the pair of end surfaces 80a, 80b of the permanent magnet 80 in the vertical direction, the pair of side surfaces forming the long side in the cross-sectional rectangle are the long side surfaces 81, 82, respectively. Of the side surfaces of the permanent magnet 80, a pair of side surfaces forming a short side in the rectangular cross section are short side surfaces 83 and 84, respectively.

  The pair of long side surfaces 81 and 82 of the permanent magnet 80 are in contact with the pair of magnet fixing walls 54 and 55 of the magnet embedding hole 53. That is, the permanent magnet 80 is fixed to the rotor core 50 by sandwiching the pair of long side surfaces 81 and 82 between the pair of magnet fixing walls 54 and 55. The magnet embedding hole 53 may have another wall for fixing the permanent magnet 80. For example, the permanent magnet 80 is fixed from the end in the longitudinal direction between the magnet fixing walls 54 and 55 and the inner space forming wall 56 or between the magnet fixing walls 54 and 55 and the outer space forming wall 57. You may have walls.

  The permanent magnet 80 is installed so that the polarities of adjacent magnetic poles are different from each other. A single magnetic pole is formed by a pair of permanent magnets 80 and 80 having a V shape when viewed in the direction of the axis O as in the case of the pair of magnet embedded holes 53. In this embodiment, since a set of eight V-shaped magnet embedded holes 53 is formed, the permanent magnet 80 is fixed to each of the plurality of magnet embedded holes 53 so that the number of poles of the rotor 40 is increased. There are 8 poles.

  Specifically, as shown in FIG. 6, the space in the magnet embedding hole 53 is partitioned into an inner space 61 and an outer space 62 by a permanent magnet 80 provided in the magnet embedding hole 53. The inner space 61 and the outer space 62 each function as a flux barrier.

  The inner space 61 is defined by the radially inner short side surface 83 of the permanent magnet 80 and the inner space forming wall 56 of the magnet embedding hole 53. The inner space 61 is in contact with the permanent magnet 80 from the radially inner side over the entire vertical region of the rotor core 50, that is, the entire vertical region of the permanent magnet 80. The inner space 61 is open to the upper end surface 50 c and the lower end surface 50 b of the rotor core 50. The inner space 61 is disposed so as to protrude and extend radially inward from the short side surface 83 of the permanent magnet 80 as viewed in the direction of the axis O. The inner space 61 is located at the vertex of the V-shape.

  A portion between the pair of inner spaces 61 located at the V-shaped apex of the pair of magnet embedding holes 53 in the rotor core 50, that is, a portion between a pair of the inner spaces 61 adjacent to each other in the circumferential direction is The inner bridge 58 is used. The inner bridge 58 extends in the radial direction in the radial existence range of the pair of inner spaces 61.

  The outer space 62 is defined by the radially outer short side surface 84 of the permanent magnet 80 and the outer space forming wall 57 of the magnet embedding hole 53. The outer space 62 is in contact with the permanent magnet 80 from the outside in the radial direction over the entire vertical region of the rotor core 50, that is, the entire vertical region of the permanent magnet 80. The outer space 62 is open to the upper end surface 50 c and the lower end surface 50 b of the rotor core 50.

Here, the outer space forming wall 57 includes a first wall surface 57a, a second wall surface 57b, and an outer peripheral wall surface 57c.
The first wall surface 57a extends radially outward from the radially inner magnet fixing wall 54 of the pair of magnet fixing walls 54 and 55 as viewed in the direction of the axis O. The second wall surface 57b extends radially outward from the radially outer magnet fixing wall 55 of the pair of magnet fixing walls 54 and 55 as viewed in the direction of the axis O.
The first wall surface 57a and the second wall surface 57b are in contact with the permanent magnet 80 as viewed in the direction of the axis O. The contact location of the second wall surface 57b with the permanent magnet 80 is more radially outward than the contact location of the first wall surface 57a with the permanent magnet 80. In the present embodiment, the second wall surface 57 b is in contact with the corners of the long side surface 82 and the short side surface 84 which are the radially outer ends of the permanent magnet 80.

  The outer peripheral side wall surface 57c extends in the circumferential direction so as to connect the radially outer ends of the first wall surface 57a and the second wall surface 57b when viewed in the direction of the axis O. The outer peripheral side wall surface 57c extends in an arc shape along a first virtual circle C1 centered on the axis O when viewed in the direction of the axis O. The first virtual circle C1 is a circle that passes through the radially outer end of the outer space 62. In the present embodiment, the first virtual circle C1 coincides with the outer peripheral side wall surface 57c as viewed in the direction of the axis O. The circumferential dimension of the outer peripheral side wall surface 57c is larger than the radial dimension of the second wall surface 57b, that is, the radial distance between the radially outer end of the permanent magnet 80 and the first virtual circle C1.

Here, a circle passing through the radially inner end of the outer space 62 with the axis O as the center is defined as a second virtual circle C2. In the present embodiment, the second virtual circle C <b> 2 passes through the connection portion between the first wall surface 57 a of the outer space forming wall 57 and the magnet fixing wall 54.
A circle that passes through the radially outer end of the permanent magnet 80 with the axis O as the center is defined as a third virtual circle C3. The radially outer end of the permanent magnet 80 is positioned radially inward of the radially outer end of the outer space 62 and is positioned radially outward of the radially inner end of the outer space 62. doing. Therefore, the diameter of the third virtual circle C3 is smaller than the diameter of the first virtual circle C1 and larger than the diameter of the second virtual circle C2.

  A portion between the outer peripheral side wall surface 57 c of the rotor core 50 and the outer peripheral surface 50 a of the rotor core 50 is an outer bridge 59. The outer bridge 59 extends in the circumferential direction over the formation range of the outer peripheral side wall surface 57c.

<First end plate>
As shown in FIGS. 3, 4, and 7, the first end plate 90 is a disk-shaped member that extends in a direction orthogonal to the axis O and whose outer shape forms a circle centered on the axis O. . The first end plate 90 is fixed so as to be stacked on the rotor core 50 from below the rotor core 50.
The first end plate 90 has an upper surface 90 a that contacts the lower end surface 50 b of the rotor core 50 from below. The first end plate 90 has a cylindrical surface with the axis O as the center and an outer peripheral surface 90b that faces radially outward. The outer diameter of the outer peripheral surface 90b of the first end plate 90 is constant in the axis O direction. The upper end of the outer peripheral surface 90 b of the first end plate 90 is connected to the upper surface 90 a of the first end plate 90 and is in contact with the lower end surface 50 b of the rotor core 50.
The first end plate 90 is formed with a circular hole 91 having a circular shape centered on the axis O at the center. The first end plate 90 is fixed to the shaft 41 by fitting a circular hole 91 to the fixing surface 43 on the outer peripheral surface of the shaft 41.

  A distribution path 92 extending in the radial direction is formed in the first end plate 90. The distribution path 92 connects the axial flow path 52 of the rotor core 50 and the inner space 61 in the radial direction. The distribution path 92 does not communicate with the outer space 62 or the space outside the rotor 40. That is, the distribution path 92 communicates only the axial flow path 52 and the inner space 61. The distribution path 92 communicates with the shaft radial hole 45 in the shaft 41 via the axial flow path 52. In the distribution path 92, a recess 93 formed in the first end plate 90 and the first end plate 90 are defined by a lower end surface 50b of the rotor core 50 from above.

  As shown in FIG. 7, a plurality of recesses 93 are formed at intervals in the circumferential direction so as to be recessed from a surface facing upward of the first end plate 90, that is, a surface in contact with the lower end of the rotor core 50. In the present embodiment, four recesses 93 are formed at equal intervals in the circumferential direction.

  Each recess 93 is constituted by a pair of distribution path forming portions 94, 94 extending in the radial direction. The pair of distribution path forming portions 94, 94 are connected to the circular hole 91 at their radially inner ends joined together. The pair of distribution path forming portions 94, 94 are branched so as to be gradually separated in the circumferential direction toward the outer side in the radial direction. As a result, each recess 93 has a V shape with the apex facing radially inward. The radially outer ends of the pair of distribution path forming portions 94, 94 in each recess 93 are closed without opening to the outer peripheral surface 90 b of the first end plate 90.

  The circumferential position of the portion corresponding to the vertex of the V shape of each recess 93 is the same as the circumferential position of the axial flow path 52 of the rotor core 50. The positions of the radially outer ends of the pair of distribution path forming portions 94, 94 in each recess 93 are positions including a pair of inner spaces 61 that are close to each other when viewed in the direction of the axis O.

  The distribution path 92 communicates the axial flow path 52 of the rotor core 50 and the inner space 61 in the radial direction at their lower ends. In the present embodiment, since a total of eight distribution path forming portions 94 are formed, eight distribution paths 92 are defined when viewed in the direction of the axis O.

  The outer diameter of the outer peripheral surface 90b of the first end plate 90 is set to be smaller than the outer diameter of the rotor core 50 and the diameter of the first virtual circle C1. That is, the outer peripheral surface 90 b of the first end plate 90 is located radially inward from the outer peripheral side wall surface 57 c that forms the radially outer end of the outer space 62. Therefore, the first end plate 90 opens an opening at the lower end surface 50 b of the rotor core 50 in the outer space 62 to the outside of the rotor 40. Thus, the first end plate 90 forms a first discharge port 62a that allows the lower end of the outer space 62 to communicate with the outside.

  Here, as shown in FIGS. 4 and 6, the outer diameter of the outer peripheral surface 90b of the first end plate 90 is set to be larger than the diameter of the second virtual circle C2. Therefore, the first end plate 90 closes a radially inner portion of the opening at the lower end of the rotor core 50 in the outer space 62 and opens a radially outer portion of the opening. That is, the first end plate 90 closes only the radially inner portion of the opening of the outer space 62. Accordingly, the first discharge port 62 a is formed so as to be biased only in the radially outer portion at the lower end of the outer space 62.

  The outer diameter of the outer peripheral surface 90b of the first end plate 90 is set to be larger than the diameter of the third virtual circle C3. Therefore, the first end plate 90 opens a small portion of the radially outer portion of the opening at the lower end of the rotor core 50 in the outer space 62. As a result, the first discharge port 62 a forms a slit-shaped first discharge port 62 a extending in the circumferential direction only at the radially outer portion at the lower end of the outer space 62. The width dimension orthogonal to the extending direction of the first discharge port 62a as viewed in the direction of the axis O of the first discharge port 62a, that is, the dimension in the radial direction of the first discharge port 62a is, for example, 0.2 to 1.5 mm, The thickness is preferably set to 0.3 to 1.0 mm, more preferably about 0.5 mm.

  As shown in FIG. 3, the vertical position of the first end plate 90 is the same as the vertical position of the upper coil end 34 a in the stator 30. Therefore, the upper coil end 34a is located on the radially outer side of the first discharge port 62a.

<Second end plate>
As shown in FIGS. 3, 4, and 8, the second end plate 96 extends in a direction orthogonal to the axis O and has a circular shape with the axis O as the center, like the first end plate 90. It is a disk-shaped member.
The second end plate 96 has a lower surface 96a that comes into contact with the upper end surface 50c of the rotor core 50 from above. The second end plate 96 has an outer peripheral surface 96b that forms a cylindrical surface centered on the axis O and faces radially outward. The outer diameter of the outer peripheral surface 96b of the second end plate 96 is constant in the axis O direction. The lower end of the outer peripheral surface 96 b of the second end plate 96 is connected to the lower surface 96 a of the second end plate 96 and is in contact with the upper end surface 50 c of 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 at the center. The second end plate 96 is fixed to the shaft 41 by fitting a circular hole 97 to the fixing surface 43 on the outer peripheral surface of the shaft 41. The second end plate 96 supports the rotor core 50 together with the first end plate 90 from above and below.

The second end plate 96 closes the axial flow path 52 in the rotor core 50 from above by the lower surface 96a.
As shown in FIG. 8, the second end plate 96 is formed with a plurality of through-holes (discharge passages) 98 penetrating in the vertical direction at intervals in the circumferential direction. In the present embodiment, a total of eight through holes 98 are formed at equal intervals in the circumferential direction.

The position of each through hole 98 is a position including a pair of axial flow paths 52 that are close to each other in the rotor core 50 when viewed in the direction of the axis O. The through hole 98 of the second end plate 96 and the inner space 61 of the rotor core 50 are communicated with each other.
As a result, a cooling flow path in which cooling oil flows in the order of the shaft center hole 44, the shaft radial hole 45, the axial flow path 52, the distribution path 92, the inner space 61, and the through hole 98 is formed in the rotor 40. Has been.

  The outer diameter of the outer peripheral surface 96b of the second end plate 96 is set smaller than the outer diameter of the rotor core 50 and the diameter of the first virtual circle C1. In other words, the outer peripheral surface 96 b of the second end plate 96 is located radially inward from the outer peripheral side wall surface 57 c that forms the radially outer end of the outer space 62. Therefore, the second end plate 96 opens the opening at the upper end surface 50 c of the rotor core 50 in the outer space 62 to the outside of the rotor 40. Thus, the second end plate 96 forms a second discharge port 62b that allows the upper end of the outer space 62 to communicate with the outside.

  Here, as shown in FIGS. 4 and 6, the outer diameter of the outer peripheral surface 96b of the second end plate 96 is set to be larger than the diameter of the second virtual circle C2. Therefore, the second end plate 96 closes the radially inner portion of the opening in the upper space 50c of the rotor core 50 in the outer space 62 from above, and opens the radially outer portion of the opening. That is, the second end plate 92 closes only the radially inner portion of the opening of the outer space 62. Accordingly, the second discharge port 62 b is formed so as to be biased only in the radially outer portion at the upper end of the outer space 62.

  The outer diameter of the outer peripheral surface 96b of the second end plate 96 is set larger than the diameter of the third virtual circle C3. Therefore, the second end plate 96 opens a small portion on the radially outer side in the opening at the upper end surface 50 c of the rotor core 50 in the outer space 62. Thus, the second discharge port 62 b forms a slit-like second discharge port 62 b extending in the circumferential direction only at the radially outer portion at the upper end of the outer space 62. The width dimension orthogonal to the extending direction of the second discharge port 62b as viewed in the direction of the axis O of the second discharge port 62b, that is, the radial dimension of the second discharge port 62b is, for example, 0.2 to 1.5 mm, The thickness is preferably set to 0.3 to 1.0 mm, more preferably about 0.5 mm.

  The vertical position of the second end plate 96 is the same as the vertical position of the lower coil end 34 b in the stator 30. Therefore, the lower coil end 34b is located on the radially outer side of the second discharge port 62b.

<Axial force application part>
The axial force imparting portion 70 has a role of imparting an axial force in a direction in which the first end plate 90 and the second end plate 96 are close to each other. As shown in FIGS. It is composed of a ring 72.

  The stepped portion 71 projects from the part of the outer peripheral surface of the shaft 41 in the form of a flange outward in the radial direction from a part in the vertical direction to the entire circumferential direction. The step portion 71 is provided integrally with the shaft 41. The step portion 71 is provided at the lower end of the fixed surface 43 of the shaft. As a result, the lower end surface 50 b of the rotor core 50 fitted on the fixed surface 43 comes into contact with the stepped portion 71 from above.

  The ring 72 has an annular shape centered on the axis O. On the inner periphery of the ring 72, a female screw that is screwed with a male screw formed on the outer peripheral surface of the shaft 41 is formed. The ring 72 is in contact with the second end plate 96 from above while being screwed into the male screw of the shaft 41. By rotating the ring 72 relative to the shaft 41, the ring 72 is moved downward according to the pitch of the male screw and the female screw. Thereby, a force is applied to the second end plate 96 from above. As a result, axial force is applied to the rotor core 50, the first end plate 90, and the second end plate 96 in a direction sandwiched from above and below by the stepped portion 71 and the ring 72. Therefore, a biasing force is applied to the rotor core 50 by the first end plate 90 and the second end plate 96 so as to sandwich the rotor core 50 from the direction of the axis O. Thereby, the steel plates of the rotor core 50 are fixed together.

<Operation and effect of motor>
When the electric motor 1 is driven, AC power is supplied to each coil 34 of the stator 30 via the inverter 139. The rotor 40 rotates with respect to the stator 30 as each permanent magnet 80 follows the rotating magnetic field generated by the coil 34. When the upper swing body 130 of the excavator 100 is turned, the electric motor 1 is driven with high torque. Therefore, the rotor core 50 and the permanent magnet 80 become high temperature due to iron loss in the rotor core 50 and eddy current loss in the permanent magnet 80. Further, the stator 30 becomes high temperature due to copper loss in the coil 34 and iron loss in the stator core 31. When a rectangular coil is used for the special coil 34, heat is easily generated in the rotor core 50. When the stator 30 becomes high temperature, the rotor core 50 becomes further high temperature by the radiant heat of the stator 30. Therefore, the 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 through 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 rotationally driven. The cooling oil flowing downward through the shaft center hole 44 is introduced into the shaft radial hole 45 branched from the shaft center hole 44 and flows outward in the radial direction. 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 axial flow path 52 in the rotor core 50. The cooling oil flows downward along the outer circumferential surface of the shaft 41 through the axial flow path 52 and is introduced into the distribution path 92 in the first end plate 90 when it reaches the first end plate 90 from the rotor core 50. Is done.

  The cooling oil flows through the distribution path 92 outward in the radial direction, and is then introduced into the inner space 61 of the rotor core 50 from its lower end. In the inner space 61, the cooling oil flows upward while in contact with the permanent magnet 80. Therefore, the permanent magnet 80 is directly cooled by the cooling oil, and thermal demagnetization of the permanent magnet 80 due to high temperature is suppressed. The cooling oil that has reached the upper end of the inner space 61 is introduced into the through hole 98 of the second end plate 96 and discharged from the upper end of the through hole 98 to the outside of the second end plate 96, that is, to the outside of the rotor 40. . At this time, the cooling oil is discharged so as to be scattered outward in the radial direction by the centrifugal force generated by the rotation of the rotor 40. As a result, cooling oil is supplied to the stator core 31 and the coil 34 of the stator 30 to cool the stator 30. Thereafter, the cooling oil dripping from the stator 30 passes through the cooling oil discharge passage 9 of the casing 2 and is discharged to the outside of the casing 2. Then, the cooling oil is cooled by the cooling unit 25 in the process of passing through the reflux flow path 23 and stored again in the cooling oil storage unit 21.

Here, in the process in which the cooling oil cools the rotor core 50, part of the cooling oil that flows upward through the inner space 61 may ooze out into the outer space 62.
That is, a gap may be partially formed between the permanent magnet 80 and the magnet fixing walls 54 and 55 of the magnet embedding hole 53 in the rotor core 50. In addition, a minute gap may be formed between the plurality of steel plates forming the rotor core 50. In such a case, a part of the cooling oil that flows upward through the inner space 61 through the gap enters the outer space 62.

  If the upper and lower ends of the outer space 62 are closed, the cooling oil that has entered the outer space 62 is not discharged from the outer space 62 but stays in the outer space 62. Since the outer space 62 is close to the stator 30, it is easily affected by radiant heat from the stator 30. Further, the eddy current of the permanent magnet 80 becomes most prominent at both ends in the longitudinal direction of the permanent magnet 80 having a rectangular cross section due to the influence of the alternating magnetic field from the stator 30, particularly at a position close to the second wall surface 57 b. For this reason, the outer space 62 tends to become high temperature in combination with the radiant heat. Therefore, unless the cooling oil that stays in the outer space 62 and becomes high temperature is not discharged, the permanent magnet 80 is demagnetized and the performance of the electric motor 1 is deteriorated.

  On the other hand, in the present embodiment, the lower end of the outer space 62 is communicated with the outside through the first discharge port 62a, and the upper end of the outer space 62 is communicated with the outside through the second discharge port 62b. Yes. Therefore, the cooling oil that has oozed out from the inner space 61 into the outer space 62 is discharged to the outside through the first discharge port 62a or the second discharge port 62b. Therefore, since the high-temperature cooling oil does not stay in the outer space 62, the outer space 62 is not inadvertently heated to a high temperature. Thus, the influence of thermal demagnetization due to the high temperature of the cooling oil in the outer space 62 can be reduced. As a result, a decrease in performance of the electric motor 1 can be avoided.

Further, the cooling oil entering the outer space 62 from the inner space 61 proceeds upward or downward in the outer space 62, and then is sequentially discharged from the first discharge port 62a or the second discharge port 62b. Therefore, the cooling effect in the outer space 62 by the cooling oil can be obtained as a secondary. As a result, the radially outer end (the radially outer short side surface 84) of the permanent magnet 80 facing the outer space 62 can be cooled.
Further, the cooling oil discharged from the first discharge port 62 a and the second discharge port 62 b is discharged outward in the radial direction according to the centrifugal force of the rotor 40. For this reason, the upper coil end 34a and the lower coil end 34b can be particularly cooled by the cooling oil discharged from the first discharge port 62a and the second discharge port 62b.

The first discharge port 62 a and the second discharge port 62 b are formed by making the outer diameters of the outer peripheral surfaces 96 b of the first end plate 90 and the second end plate 96 each having a circular shape smaller than the outer diameter of the outer space 62. Is formed. Therefore, it is not necessary to separately form a discharge port that penetrates the first end plate 90 and the second end plate 96. As a result, the strength of the first end plate 90 and the second end plate 96 can be prevented from decreasing.
In particular, even when an axial force is applied to the first end plate 90 and the second end plate 96 by the axial force applying unit 70 as in the present embodiment, the first end plate 90 and the first end plate 90 capable of resisting the axial force are provided. The strength of the second end plate 96 can be ensured.

Here, if a discharge port for communicating the outer space 62 with the outside is formed in the rotor core 50 itself in order to discharge the cooling oil in the outer space 62 to the outside, the following problems occur.
That is, if a discharge port that opens in the vertical direction is formed at a location corresponding to the outer bridge 59 of the rotor core 50, the permanent magnet 80 may be detached due to the influence of centrifugal force. Moreover, it leads also to the performance fall of the electric motor 1 because magnetic flux leaks vertically.
Further, in the case where discharge ports are formed at intervals in the vertical direction at locations corresponding to the outer bridge 59 of the rotor core 50, a plurality of types of steel plates are required to form the rotor core 50. That is, it is necessary to use at least two types of molds, that is, a steel plate in a portion where the discharge port is formed and a steel plate in a portion where the discharge port is not formed, which increases manufacturing costs. Further, a decrease in strength and leakage of magnetic flux in the vertical direction are unavoidable.

  On the other hand, in the present embodiment, the upper end and the lower end of the outer space 62 are not appropriately formed by separately setting the outer diameters of the first end plate 90 and the second end plate 96 instead of separately forming discharge ports in the rotor core 50. The structure which discharges cooling oil from is adopted. Therefore, since the cooling oil in the outer space 62 can be discharged without changing the shape of the rotor core 50 itself, the above-described drawback does not occur.

Further, since the outer diameters of the first end plate 90 and the second end plate 96 are smaller than the first virtual circle C1 and larger than the second virtual circle C2, the first discharge port 62a and the second discharge port 62b are formed in the outer space 62. The lower end and the upper end are formed so as to be biased only in the radially outer portion. Therefore, the cooling oil discharged from the outer space 62 can be positively discharged radially outward. Therefore, the cooling oil discharged from the first discharge port 62a and the second discharge port 62b can be guided radially outward in conjunction with the centrifugal force generated by the rotation of the rotor 40. Thereby, cooling of the upper coil end 34a and the lower coil end 34b can be performed more effectively.
Further, since the outer diameters of the first end plate 90 and the second end plate 96 are set in the above range, the first end plate 90 and the second end plate 96 exist up to the region on the outer peripheral side of the rotor core 50. ing. Therefore, the first end plate 90 and the second end plate 96 can appropriately apply a biasing force to the steel plates constituting the rotor core 50 even in the region on the outer peripheral side of the rotor core 50.
Thus, by setting the outer diameters of the first end plate 90 and the second end plate 96 to a value between the outer diameter of the first virtual circle C1 and the outer diameter of the second virtual circle C2, the outer space 62 It is possible to achieve both the discharge of the cooling oil and the fixing of the rotor core 50.

  Moreover, the 1st discharge port 62a and the 2nd discharge port 62b are each extended in the slit shape which makes the circumferential direction a longitudinal direction. Thereby, the cooling oil in the outer space 62 can be discharged to the outside while being dispersed in the circumferential direction. Accordingly, the cooling oil can be discharged from the first discharge port 62a and the second discharge port 62b to a wide range in the circumferential direction. That is, the cooling oil can be supplied uniformly over the entire circumferential direction without being biased toward partial areas in the circumferential direction of the upper coil end 34a and the lower coil end 34b.

  Here, the outer bridge 59 suppresses the passage of magnetic flux beyond that by reducing the width of the magnetic path and causing magnetic saturation. As a result, an increase in leakage magnetic flux that does not contribute to the rotation of the electric motor 1 is suppressed. In the present embodiment, since the first discharge port 62a and the second discharge port 62b are formed in a slit shape extending in the circumferential direction, the outer bridge 59 also extends in the circumferential direction. That is, since the outer bridge 59 is lengthened, a region where the magnetic flux cannot pass can be expanded, and an increase in leakage magnetic flux can be further suppressed.

  Here, for example, a second discharge port 62b as shown in FIG. 9 may be adopted as a first modification of the first embodiment. In the first modified example, the lower end portion of the outer peripheral surface 96 b of the second end plate 96 connected to the lower surface 96 a of the second end plate 96 is chamfered so that the outer diameter decreases as the rotor core 50 is approached. The tapered surface 96c is formed. Of the outer peripheral surface 96b of the second end plate 96, the portion above the tapered surface 96c excluding the tapered surface 96c is a cylindrical surface 96d centered on the axis O.

  The outer diameter of the cylindrical surface 96d on the outer peripheral surface 96b of the second end plate 96 is set to a value equal to or larger than the diameter of the first virtual circle C1. On the other hand, the outer diameter of the lower end of the tapered surface 96c on the outer peripheral surface 96b of the second end plate 96 is set smaller than the diameter of the first virtual circle C1 as in the first embodiment. The outer diameter of the lower end of the taper surface 96c is set larger than the diameter of the second virtual circle C2, and preferably larger than the diameter of the third virtual circle C3.

Thus, the outer diameter of a part of the outer peripheral surface 96b of the second end plate 96 (the end on the rotor core 50 side) is larger than the diameter of the first virtual circle C1 that passes through the outer end of the outer space 62 in the radial direction. Even if it is small, the 2nd discharge port 62b is formed like 1st embodiment. Accordingly, the cooling oil in the outer space 62 can be smoothly discharged to the outside through the second discharge port 62b.
In particular, in the first modified example, the tapered surface 96c extends radially outward as the distance from the outer space 62 increases. I can guide you. Therefore, the cooling oil can be positively supplied by the upper coil end 34a.

  Further, for example, a second discharge port 62b as shown in FIG. 10 may be adopted as a second modification of the first embodiment. In the second modification, the second discharge port 62b is formed as a hole 99a penetrating the second end plate 96 in the vertical direction. The hole 99 a is formed at a circumferential position corresponding to each outer space 62 and communicates with the outer space 62. Therefore, the cooling oil in the outer space 62 can be discharged upward through the hole 99a.

  Furthermore, for example, the configuration shown in FIG. 11 may be used as a third modification of the first embodiment. In the third modification, the second discharge port 62b is a hole 99b that opens to the lower surface 96a of the second end plate 96 and communicates with the outer space 62 and opens to the outer peripheral surface 96b of the second end plate 96. . The hole 99 b is formed at a position corresponding to the outer space 62. In this case, the cooling oil in the outer space 62 is positively discharged radially outward through the hole 99b. Thereby, the upper coil end 34a can be cooled more effectively.

  Further, for example, the configuration shown in FIG. 12 may be used as a fourth modification of the first embodiment. In the fourth modified example, the outer diameter of the outer peripheral surface 96b of the second end plate 96 is formed larger than the first virtual circle C1, and the recesses 99c that are recessed radially inward from the outer peripheral surface are spaced apart in the circumferential direction. Open and formed. The recess 99 c is formed at a position corresponding to the outer space 62 and communicates with the upper end of the outer space 62. As a result, a second discharge port 62b that allows the outer space 62 to communicate with the outside is formed. Even in this case, the cooling oil in the outer space 62 can be discharged to the outside as described above.

In the second to fourth modifications, the urging force from the first end plate 90 to the rotor core 50 is reduced at the outer peripheral position by the amount of the holes 99a and 99b and the recess 99c. Therefore, it is preferable that the steel plates constituting the rotor core 50 are fixed with resin or the like.
In the first to fourth modifications, the second end plate 96 and the second discharge port 62b have been described. However, the first end plate 90 and the second discharge port 62b may have the same configuration.

Next, a rotor 40A according to a second embodiment of the present invention 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 thereof is omitted.
The second embodiment is different from the first embodiment in the configuration of the permanent magnet 180. Both end surfaces 180a and 180b in the vertical direction of the permanent magnet 180 of the second embodiment are in the magnet embedding hole 53, that is, the axis O of the magnet embedding hole 53, than the upper end surface 50c and the lower end surface 50b of the rotor core 50, respectively. It is set back in the direction.

  In other words, the lower end surface 180 a of the permanent magnet 180 is arranged to be spaced upward from the lower end surface 50 b of the rotor core 50. The lower end surface 180 a of the permanent magnet 180 is also spaced upward from the upper surface 90 a of the first end plate 90. As a result, a lower end communication passage 185 that connects the inner space 61 and the outer space 62 within the magnet embedding hole 53 is formed between the lower end surface 180 a of the permanent magnet 180 and the upper surface 90 a of the first end plate 90. A compartment is formed. The lower end communication passage 185 allows the inner space 61 and the outer space 62 to communicate with each other in the longitudinal direction (radial direction and circumferential direction) of the magnet embedding hole 53 as viewed in the direction of the axis O.

  The upper end surface 180 b of the permanent magnet 180 is disposed to be spaced downward from the upper end surface 50 c of the rotor core 50. The upper end surface 180 b of the permanent magnet 180 is also spaced downward from the lower surface 96 a of the second end plate 96. Thus, an upper end communication passage 186 that connects the inner space 61 and the outer space 62 in the magnet embedding hole 53 is formed between the upper end surface 180 b of the permanent magnet 180 and the lower surface 96 a of the second end plate 96. A compartment is formed. The upper end communication passage 186 allows the inner space 61 and the outer space 62 to communicate with each other in the longitudinal direction (the radial direction and the circumferential direction) of the magnet embedding hole 53 as viewed in the direction of the axis O.

  Here, in this embodiment, the permanent magnet 180 is configured by arranging a plurality (two in this embodiment) of magnet pieces 182 spaced apart from each other in the vertical direction. Between the magnet pieces 182 adjacent to each other in the direction of the axis O, an internal communication path 187 that communicates the inner space 61 and the outer space 62 within the magnet embedding hole 53 is defined. The internal communication path 187 allows the inner space 61 and the outer space 62 to communicate with each other in the longitudinal direction (radial direction and circumferential direction) of the magnet embedding hole 53 as viewed in the direction of the axis O.

  In the present embodiment, in addition to the cooling oil flowing through the inner space 61 oozing out into the outer space 62, the inner space 61 is connected via the lower end communication passage 185, the upper end communication passage 186 and the internal communication passage 187. The cooling oil can be positively supplied to the outer space 62. Therefore, a large amount of cooling oil can be circulated through the outer space 62. Accordingly, the cooling oil can be appropriately supplied into the outer space 62 that is particularly likely to become high temperature, and the radially outer side of the permanent magnet 180 in which a large eddy current is generated can be effectively cooled.

Here, when the flow path for introducing the cooling oil into the outer space 62 is formed in the first end plate 90 or the second end plate 96, the first end plate 90, The rigidity of the second end plate 96 is lowered. Particularly in the case of the structure in which the first end plate 90, the second end plate 96, and the rotor core 50 are fastened by the axial force by the axial force applying unit 70 as in the present embodiment, the rigidity is sufficient to resist the axial force. Therefore, measures such as increasing the thicknesses of the first end plate 90 and the second end plate 96 are required.
Furthermore, if it is going to form a flow path in the rotor core 50, several types of steel plates from which a shape differs will be needed, and cost will increase only by the part which uses the some type | mold corresponding to these steel plates.

  On the other hand, in the present embodiment, the outer space 62 is simply adjusted by adjusting the sizes of the permanent magnet 180 and the magnet piece 182 without newly forming a flow path in the first end plate 90 and the second end plate 96. A flow path for guiding the cooling oil to is formed. For this reason, the cooling oil can be appropriately supplied to the outer space 62 without causing the above-described drawbacks.

Next, a rotor 40B according to a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
The third embodiment is different from the first embodiment in the configuration of the distribution path 192 of the first end plate 190.

  A plurality of distribution paths 192 of the third embodiment are formed at intervals in the circumferential direction. In the present embodiment, a plurality of distribution paths 192 are formed at intervals of 90 ° in the circumferential direction. Each distribution path 192 has a radial flow path 193 and a circumferential flow path 194.

  The radial flow path 193 extends in the radial direction, and the radially inner end is connected to the circular hole 91. The circumferential position of the radially inner end of the radial flow path 193 is the same as the circumferential position of the axial flow path 52 of the rotor core 50. The outer end of the radial flow path 193 does not reach the outer peripheral surface 96 b of the second end plate 96. The radial flow path 193 extends along a reference line P that extends in the radial direction. In the present embodiment, the reference line P passes through the center in the width direction (circumferential direction) of the radial flow path 193.

The circumferential channel 194 is connected to the radially outer end of the radial channel 193. The circumferential channel 194 extends from the radially outer end of the radial channel 193 toward both sides in the circumferential direction. In the present embodiment, the circumferential flow path 194 extends linearly perpendicular to the radial flow path 193 when viewed in the direction of the axis O. Thereby, the distribution path 192 of the present embodiment has a T-shape when viewed in the direction of the axis O. The circumferential flow path 194 only needs to intersect the radial flow path 193.
Both ends in the circumferential direction of the circumferential flow path 194 are positions including a pair of inner spaces 61 that are close to each other when viewed in the direction of the axis O. In other words, the circumferential flow path 194 communicates with the lower end of the inner space 61 at both ends in the circumferential direction.

  Such a distribution path 192 is formed by a recess 195 that is recessed from the upper surface 90 a of the first end plate 190. The recess 195 includes a radial recess 196 that forms the radial flow path 193 and a radial recess 196 that forms the circumferential flow path 194.

  The radially outer portion of the circumferential recess 197 is a pair of flow channel back surfaces 198 extending linearly from the center line of the radial flow channel 193 toward one side and the other side in the circumferential direction. The flow path back surface 198 is a surface parallel to the axis O. In the present embodiment, the channel back surface 198 extends orthogonally to the reference line P of the radial channel 193. Therefore, the flow path back surface 198 gradually extends in the radial direction as it is separated from the reference line P in the circumferential direction.

  In the present embodiment, the cooling refrigerant supplied from the axial flow path 52 to the distribution path 192 is introduced into the inner space 61 of the rotor core 50 via the radial flow path 193 and the circumferential flow path 194. In the present embodiment, the circumferential flow path 194 extends in the circumferential direction at a radially outer portion of the rotor core 50. Therefore, the first end plate 190 can be cooled over a wide range in the circumferential direction in the course of the cooling oil flowing through the circumferential flow path 194. In particular, the radially outer portion of the first end plate 190 is likely to become high temperature due to the influence of radiant heat from the stator 30 and eddy current due to the alternating magnetic flux from the stator 30. In the present embodiment, the formation of the circumferential flow path 194 can suppress an increase in temperature at the outer peripheral side portion of the first end plate 190.

  Further, in the present embodiment, the pair of flow channel back surfaces 198 forming the circumferential flow channel 194 are orthogonal to the radial flow channel 193, and thus extend outward in the radial direction as they are separated in the circumferential direction. Yes. Therefore, there is no place where the cooling refrigerant stays in the process of flowing the cooling refrigerant from the radial flow path 193 to the end of the circumferential flow path 194. If a part of the flow path back surface 198 extends radially inward as it is separated from the radially outer side, the cooling oil stays in the portion due to the centrifugal force. In this embodiment, since the flow path back surface 198 is directed radially outward as it goes toward the end of the circumferential flow path 194, there is no cooling oil convection point. The cooling oil introduced from the radial flow path 193 into the circumferential flow path 194 is smoothly guided to the end of the circumferential flow path 194 by centrifugal force and introduced into the inner space 61.

  In addition, the flow path back surface 198 does not necessarily have to be linear when viewed in the direction of the axis O. Even in this case, it is sufficient that there is no portion that goes radially inward as the distance from the radial flow path 193 increases in the circumferential direction. In other words, the flow path back surface 198 only needs to gradually go outward in the radial direction as it is separated from the radial flow path 193 in the circumferential direction. Note that a part of the flow path back surface 198 may have a portion extending in an arc shape with the axis O as the center.

  In addition, when the flow path back surface 198 extends linearly when viewed in the direction of the axis O, the following relationship may be satisfied. That is, when the distance from the axis O at the circumferential end of the flow path back surface 198 is R1, and the distance from the axis O at the intersection with the reference line P of the radial flow path 193 at the flow path back surface 198 is R2. It is only necessary that the relationship of R1> R2 is established. Here, when the number of poles is P, R2 = R1 cos (π / P). In this case, the channel back surface 198 always extends outward in the radial direction from the radial channel 193 toward the circumferential end.

<Other embodiments>
The embodiment of the present invention has been described above, but the present invention is not limited to this, and can be appropriately changed without departing from the technical idea of the present invention.
For example, in the embodiment, the example in which the first discharge port 62a is formed by the first end plate 90 and the second discharge port 62b is formed by the second end plate 96 has been described. It is sufficient that at least one of the discharge ports 62b is formed.

The shapes of the first discharge port 62a and the second discharge port 62b are not limited to the slit shape extending with a uniform width in the circumferential direction, and may be other shapes. For example, it may be a slit shape in which the width dimension increases or decreases toward the one side in the circumferential direction. Moreover, the 1st discharge port 62a and the 2nd discharge port 62b are not restricted to a slit shape, Other shapes may be sufficient.
In 1st embodiment, it was set as the structure which spread | circulates the cooling oil which distribute | circulated the inside of the rotor 40 to the stator 30, However, You may provide the cooling path | route which cools the stator 30 separately from the cooling path | route inside the rotor 40. The cooling oil may be directly supplied to the stator 30 from the outside.
In the first embodiment, the axial flow path 52 extends along the outer peripheral surface of the shaft 41. The axial flow path 52 may be formed inside the rotor core 50 without contacting the outer peripheral surface of the shaft 41.

The flow path for supplying the cooling oil to the distribution path 92 of the first end plate 90 is not limited to the configuration of the embodiment, and other configurations may be adopted. Any other configuration may be used as long as the cooling oil supplied from the outside is supplied to the distribution path 92.
In the embodiment, the example in which the cooling oil is used as the cooling medium has been described. However, a cooling medium made of cooling air or another medium may be used.

In the embodiment, the vertical type in which the axis O of the electric motor 1 is aligned in the vertical direction has been described. However, the vertical type may be applied to a horizontal type in which the axis O is aligned in the horizontal direction. You may arrange | position so that it may correspond.
Moreover, although embodiment demonstrated the example which transmits the output of the electric motor 1 to the swing pinion 123, the electric motor 1 may be connected to the swing pinion 123 via the planetary gear reducer, for example.

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 present invention is applied to the electric motor 1 of the excavator 100 as a work machine has been described, but the present invention may be applied to the electric motor 1 of another work machine.

DESCRIPTION OF SYMBOLS 1 ... Electric motor, 2 ... Casing, 3 ... Cylindrical part, 4 ... 1st cover part, 5 ... Shaft accommodating part, 6 ... Cooling oil introduction hole, 7 ... 2nd cover part, 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 ... cooling oil supply part (Cooling medium supply unit), 21 ... Cooling oil storage unit, 22 ... Introduction channel, 23 ... Reflux channel, 24 ... Cooling oil pump, 25 ... Cooling unit, 30 ... Stator, 31 ... Stator core, 32 ... Yoke, 33 ... Teeth, 34 ... Coil, 34a ... Upper coil end, 34b ... Lower coil end, 40 ... Rotor, 41 ... Shaft, 43 ... Fixed surface, 44 ... Shaft center hole, 45 ... Shaft radial hole, 50 ... Rotor core, 50a ... outer peripheral surface, 50b ... lower end surface, 50c ... upper end surface 51 ... Core central hole, 52 ... Axial flow path, 53 ... Magnet embedding hole, 54 ... Magnet fixing wall, 55 ... Magnet fixing wall, 56 ... Inner space forming wall, 57 ... Outer space forming wall, 57a ... First Wall surface, 57b ... second wall surface, 57c ... outer peripheral side wall surface, 58 ... inner bridge, 59 ... outer bridge, 61 ... inner space, 62 ... outer space, 62a ... first discharge port, 62b ... second discharge port, 70 ... Axial force imparting portion, 71 ... step portion, 72 ... ring, 80 ... permanent magnet, 80a ... end face, 80b ... end face, 81 ... long side face, 82 ... long side face, 83 ... short side face, 84 ... short side face, 90 ... first One end plate, 90a ... upper surface, 90b ... outer peripheral surface, 91 ... circular hole, 92 ... distribution channel, 93 ... recessed portion, 94 ... distribution channel forming portion, 96 ... second end plate, 96a ... lower surface, 96b ... outer peripheral surface, 96c ... Tapered surface, 96d ... Cylindrical surface, 9 DESCRIPTION OF SYMBOLS ... Circular hole, 98 ... Through-hole (discharge path), 99a ... Hole part, 99b ... Hole part, 99c ... Recessed part, 100 ... Hydraulic excavator, 110 ... Undercarriage, 111 ... Track, 120 ... Swing circle, 121 ... Outer Race, 122 ... Inner race, 123 ... Swing pinion, 130 ... Upper turning body, 131 ... Cab, 132 ... Working machine, 133 ... Boom, 134 ... Arm, 135 ... Bucket, 136 ... Engine, 137 ... Generator motor, 138 ... hydraulic pump, 139 ... inverter, 140 ... capacitor, 180 ... permanent magnet, 180a ... end face, 180b ... end face, 182 ... magnet piece, 185 ... lower end communication path, 186 ... upper end communication path, 187 ... internal communication path, 190 ... first end plate, 192 ... distribution channel, 193 ... radial channel, 194 ... circumferential channel, 195 ... concave, 19 6 ... Radial recess, 197 ... Circumferential recess, 198 ... Channel back, L ... Swivel axis, O ... Axis, P ... Reference line, C1 ... First virtual circle, C2 ... Second virtual circle, C3 ... Third Virtual circle

Claims (8)

An axially extending shaft;
A plurality of steel plates stacked in the axial direction are fixed to the outside in the radial direction of the shaft, and a plurality of magnet embedded holes penetrating in the axial direction are formed at intervals in the circumferential direction. The rotor core,
A plurality of permanent magnets that are provided in each of the magnet embedding holes and divide a space in the magnet embedding hole into an inner space and an outer space that extends radially outward from the inner space in the axial direction;
A distribution path is provided so as to abut against the end surface on one axial direction side of the rotor core and supplies a cooling medium supplied from the outside only to the inner space of the inner space and the outer space. One end plate,
A second end plate that is provided so as to be in contact with the end surface on the other axial side of the rotor core, and that has a discharge path for discharging the cooling medium flowing through the inner space to the outside;
With
A rotor in which at least one of the first end plate and the second end plate forms a discharge port that communicates an end of the outer space in the axial direction with the outside.   An outer diameter of at least one outer peripheral surface of the first end plate and the second end plate is formed smaller than a diameter of a first imaginary circle passing through an end portion on the radially outer side of the outer space around the axis. The rotor according to claim 1, wherein the discharge port is formed.   The outer diameter of at least one outer peripheral surface of the first end plate and the second end plate is a diameter of a second imaginary circle that passes through the radially inner end on the inner peripheral side of the outer space around the axis. The rotor of claim 2, which is larger than 3.   The end surface of the permanent magnet, the first end plate, and the second end are at least one end surface in the axial direction of the permanent magnet retracted into the magnet embedding hole from the end surface of the rotor core. The rotor according to any one of claims 1 to 3, wherein an end communication path that connects the inner space and the outer space is formed between the plate and the plate. The permanent magnet comprises a plurality of magnet pieces arranged in the axial direction within the magnet embedding hole,
The rotor according to any one of claims 1 to 4, wherein an internal communication path that connects the inner space and the outer space is formed between the magnet pieces adjacent to each other in the axial direction. The distribution path is
A radial flow path that extends in the radial direction and is supplied with cooling refrigerant at the radially inner end; and
A circumferential flow path extending from the radially outer end of the radial flow path to both sides in the circumferential direction intersecting the radial flow path and communicating with the inner space on both circumferential sides;
The rotor according to any one of claims 1 to 5, having the following. A rotor according to any one of claims 1 to 6;
A stator core that surrounds the rotor core from the outer peripheral side, and a stator having a plurality of coils provided at intervals in the circumferential direction on the stator core;
A cooling medium supply unit for supplying the cooling medium to the rotor core;
An electric motor. A lower traveling body,
An upper swing body provided on the lower traveling body,
The electric motor according to claim 7, wherein the axis is arranged so as to extend in a vertical direction, and the upper swing body is swung around the axis with respect to the lower traveling body.
Hydraulic excavator with.

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