Rotating electric machine and drive device equipped with the same

Abstract

To simplify a cooling structure and suppress increases in production cost.SOLUTION: In a rotary electric machine according to the present invention, a rotation axis of a rotor shaft 26 is arranged at a predetermined angle with respect to a horizontal axis. An upper channel 252 that is formed above a stator core 23a and through which a liquid refrigerant flows, a lower channel 255 that is formed below the stator core 23a, and a slot channel 257 that communicates the upper channel 252 and the lower channel 255 are provided in the rotary electric machine. The upper channel 252 is formed by a housing 25, an upper end surface of the stator core 23a, and an upper channel forming body 251 that connects the housing 25 and an upper end surface of the stator core 23a on a gap G side. At least a portion of an end surface of the slot channel 257 on the gap G side is open.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a rotating electric machine and a drive device including the same. [Background technology]

[0002] As we move towards a carbon-free and autonomous driving society, the electrification of automobiles is progressing. Accompanying this trend, various technologies for cooling rotating electric machines have been proposed. One example is a technology in which an oil pump is connected to a rotating electric machine with its rotating shaft positioned horizontally, and cooling oil is pumped into the rotating electric machine to cool the stator and rotor inside the rotating electric machine. With this technology, the rotating electric machine is filled with cooling oil, and the rotor rotates while immersed in the cooling oil, which generates fluid friction loss in the rotor.

[0003] To solve this problem, there is a technology described in Patent Document 1. In Patent Document 1, a stator and a rotor are disposed within the case of a rotating electric machine. A plurality of slots are formed in the stator core of the stator, and coils are disposed within the slots. A resin layer is disposed at the rotor-side opening of the slots to connect the tips of the teeth and seal the opening. In addition, a cylindrical portion is disposed between the case and the stator core, and a sealing member is disposed in the gap between the cylindrical portion and the stator core. With this configuration, the coils disposed within the slots of the stator core are disposed in an enclosed space by the case, cylindrical portion, and resin layer. In Patent Document 1, cooling oil is circulated within this enclosed space to cool the coil ends of the coils. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-87165 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technology described in Patent Document 1, a resin layer is placed to connect the tips of the teeth, and a sealing member is placed in the gap between the cylindrical portion and the stator core, which creates a complex structure, reducing the productivity of the rotating electric machine and increasing production costs.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a rotating electric machine and a drive unit including the same, in which the cooling structure is simplified and an increase in production costs is suppressed. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a rotating electric machine comprising: a cylindrical stator core having a plurality of slots in which coils are fitted; a rotor core that faces the stator core in the radial direction thereof via a predetermined gap; a rotor shaft that rotates together with the rotor core; and a housing that stores the stator core, the rotor core, and the rotor shaft, wherein the rotation axis of the rotor shaft is arranged at a predetermined angle with respect to a horizontal axis; an upper flow passage formed above the stator core through which a liquid refrigerant flows; a lower flow passage formed below the stator core; and a slot flow passage that connects the upper flow passage and the lower flow passage, wherein the upper flow passage is formed by the housing, an upper end surface of the stator core, and an upper flow passage forming body that connects the housing to the upper end surface of the stator core on the gap side, and wherein at least a portion of the end surface of the slot flow passage on the gap side is open. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a rotating electric machine and a drive unit including the same, in which the cooling structure is simplified and an increase in production costs is suppressed. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a configuration diagram showing a vehicle 100 equipped with a drive device 1 according to a first embodiment of the present invention. [Figure 2] 1 is an exploded perspective view showing a drive device 1 according to a first embodiment of the present invention. [Figure 3] 1 is an exploded perspective view showing a part of a driving device 1 in which a motor 2 according to a first embodiment of the present invention is disassembled. [Figure 4] 1 is a perspective view of a drive device 1 according to a first embodiment of the present invention, cut in half at a longitudinal cross section. [Figure 5] 1 is a vertical cross-sectional view showing a drive device 1 according to a first embodiment of the present invention. [Figure 6A] 1 is an enlarged perspective view of a cross section of a motor according to a first embodiment of the present invention, with a rotor removed. [Figure 6B] FIG. 6B is an enlarged view of part VIB in FIG. 6A. [Figure 7] 1 is a schematic cross-sectional view of a motor according to a first embodiment of the present invention. [Figure 8] FIG. 2 is a schematic diagram showing the flow of a liquid refrigerant according to the first embodiment of the present invention. [Figure 9] 10 is a schematic view of a part of a motor 2 according to a comparative example, viewed from the axial direction. [Figure 10] 1 is a schematic view of a part of a motor 2 according to a first embodiment of the present invention, viewed from the axial direction. [Figure 11] FIG. 10 is an enlarged perspective view of a cross section of a motor according to a second embodiment of the present invention, with the rotor removed. [Figure 12] FIG. 6 is a schematic cross-sectional view of a motor according to a second embodiment of the present invention. [Figure 13] FIG. 6 is a schematic diagram showing the flow of a liquid refrigerant according to a second embodiment of the present invention. [Figure 14] FIG. 10 is a schematic cross-sectional view of a motor according to a third embodiment of the present invention. [Figure 15] FIG. 10 is a schematic diagram showing the flow of a liquid refrigerant according to a third embodiment of the present invention. [Figure 16] FIG. 10 is a perspective view of a drive device 1 according to a fourth embodiment of the present invention, cut in half along a longitudinal section. [Figure 17] FIG. 10 is a cross-sectional view of a drive unit 1 according to a fourth embodiment of the present invention, as viewed from the drive shaft 106 side. [Figure 18]FIG. 2 is a cross-sectional view of the drive unit 1 when the vehicle is decelerating or traveling downhill. [Figure 19] 1 is a cross-sectional view of the drive unit 1 when the vehicle is accelerating or climbing a slope. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Like elements are designated by like reference numerals and similar descriptions will not be repeated.

[0011] The various components of the present invention do not necessarily have to be independent entities, and it is acceptable for one component to be made up of multiple members, for multiple components to be made up of one member, for one component to be part of another component, or for part of one component to overlap with part of another component.

[0012] In each figure, the U direction is the upward direction, the D direction is the downward direction, the F direction is the front direction, the B direction is the rear direction, the R direction is the right direction, and the L direction is the left direction. [Example]

[0013] <Overall configuration of vehicle 100> FIG. 1 is a configuration diagram showing a vehicle 100 equipped with a drive device 1 according to a first embodiment of the present invention.

[0014] The vehicle 100 comprises a centrally arranged drive unit 1, a chassis 101 on which the drive unit 1 is mounted, a support member 102 that fixes the drive unit 1 to the chassis 101, wheels 103 which are front wheels arranged in the forward direction F of the vehicle 100, wheels 104 which are rear wheels arranged in the rear direction B of the vehicle 100, and a battery 105 that supplies power to the drive unit 1.

[0015] The drive unit 1 is housed in an engine compartment between the wheels 103 in the front direction F of the vehicle 100. The drive unit 1 is connected to the wheels 103 via a drive shaft .

[0016] The drive shaft 106 connects the differential side gear and the wheels. The drive shaft 106 extends in the right direction R and the left direction L. Because the suspension is movable, two constant velocity joints are provided between the drive shaft 106 and the wheels. Here, the drive shaft 106 is defined as the section from the drive unit 1 to the first constant velocity joint.

[0017] The drive unit 1 may be stored between the wheels 104 in the rear direction B of the vehicle 100 to drive the wheels 104, or two may be installed and placed between the wheels 103 and 104, respectively, to provide four-wheel drive.

[0018] <Driver 1> FIG. 2 is an exploded perspective view of the drive device 1 according to the first embodiment of the present invention. FIG. 3 is an exploded perspective view of the drive device 1 with the motor 2 according to the first embodiment of the present invention disassembled. FIG. 4 is a perspective view of half of the drive device 1 according to the first embodiment of the present invention in a longitudinal cross section. FIG. 5 is a longitudinal cross section of the drive device 1 according to the first embodiment of the present invention.

[0019] The drive device 1 includes a motor 2 as a rotating electric machine, an inverter 3, a bevel gear 4, a ring gear 5, a distribution mechanism 6, a differential case 7, and a differential housing 8.

[0020] <Motor 2 (rotating electric machine)> The motor 2 includes a rotor 24 having a rotor cylindrical portion 24a, a stator 23 having a cylindrical stator core 23a and coils 23b fitted in a plurality of slots 23d (FIG. 6A) formed between a plurality of teeth 23c of the stator core 23a, a rotor shaft 26 fixed to the inner periphery of the rotor 24 and rotating together with the rotor 24, a connecting portion 22 connecting the rotor shaft 26 to the rotor cylindrical portion 24a, a gear shaft 41 integrated with the rotor shaft 26, and a housing 25 that stores these components. The rotor cylindrical portion 24a is provided with a rotor core 24b. The rotor core 24b is disposed radially opposite the stator core 23a with a predetermined gap G therebetween.

[0021] The motor 2 of this embodiment is disposed so that the rotation axis (rotation center axis O) is aligned in the vertical direction.

[0022] <Inverter 3> The inverter 3 converts DC power supplied from the battery 105 into AC power and supplies it to the motor 2.

[0023] <Bevel gear 4> The bevel gear 4 is disposed on the rotation axis (rotation center axis O) of the motor 2, and the driving force of the motor 2 is transmitted via a connection part 22 connected to the rotor cylindrical part 24a. The bevel gear 4 is provided at the axial lower end part of a gear shaft 41 integrated with the rotor shaft 26, and the rotational driving force of the rotor 24 is transmitted to the bevel gear 4.

[0024] The bevel gear 4 is connected to the rotor 24 via a connection portion 22 and a rotor cylindrical portion 24a. The bevel gear 4 is smaller in size than the ring gear 5, and also serves as a reduction gear.

[0025] Note that the bevel gear 4 may be a miter bevel gear with the same number of teeth as the ring gear 5, with the tooth tips angled 45° with respect to the center of rotation, resulting in a reduction ratio of 1:1. However, using a miter bevel gear increases the total mass of the bevel gear 4 and ring gear 5. For this reason, the bevel gear 4 is used in combination with a bevel gear 4 and ring gear 5 of appropriate sizes.

[0026] Bevel gears 4 are classified according to the shape of their teeth into spiral bevel gears and straight bevel gears.

[0027] Spiral bevel gears have curved tooth tips, which makes them difficult to manufacture, but they have a higher meshing ratio, which reduces vibration and noise. However, spiral bevel gears generate thrust loads in the axial direction, so care must be taken when using them.

[0028] Straight bevel gears have a small thrust load and the thrust load is always limited to a receding direction, which gives them the advantage of simplifying the bearing structure.

[0029] In the first embodiment, a spiral bevel gear is used as the bevel gear 4. However, the shape of the tooth tip of the bevel gear 4 is not limited.

[0030] <Gear shaft 41> The gear shaft 41 extends in an axial direction, which is a vertical direction facing upward U and downward D. The gear shaft 41 is a cylindrical member. The bevel gear 4 is fixed to the lower end of the gear shaft 41 in the downward direction D.

[0031] <Ring gear 5> The ring gear 5 is disposed so that its center of rotation faces the radial direction of the motor 2. The ring gear 5 is fixed to a differential case 7 and meshes with the bevel gear 4.

[0032] The ring gear 5 is disposed with its center of rotation facing leftward L toward the gear shaft 41, i.e., toward the inner diameter of the motor 2. The ring gear 5 has a gear tooth surface portion 51 that faces leftward L and has gear teeth at a predetermined taper angle, and an inner circumferential surface portion 52 of the gear tooth surface portion 51 that faces the drive shaft 106. The inner circumferential surface portion 52 is connected to the differential case 7.

[0033] <Distribution mechanism 6> The distribution mechanism 6 transmits the driving force of the motor 2 to the drive shaft 106 (axle) via the bevel gear 4 and the ring gear 5. The distribution mechanism 6 and the ring gear 5 are arranged opposite to each other with the rotation axis (rotation center axis O) of the rotor shaft 26 (motor 2) as the center.

[0034] The distribution mechanism 6 is a mechanism that distributes torque transmitted from the motor 2 via one shaft equally to the two drive shafts of the drive shaft 106. When the vehicle 100 is cornering, there is a difference in turning radius between the inner and outer wheels 103. As a result, the outer wheels move a longer distance than the inner wheels, and their rotational speed is also higher. The distribution mechanism 6 imparts a difference in rotational speed between the left and right wheels 103 (also called differential), so that the same torque is transmitted to both wheels 103.

[0035] A typical bevel gear type distribution mechanism is composed of a final drive gear (bevel gear 4), a ring gear 5 (final driven gear), a differential case 7, a differential side gear, a differential pinion, and a differential pinion shaft. The driving force from the power generation source of the motor 2 is transmitted to the ring gear 5 integrated with the differential case 7 using the final drive gear, causing the differential pinion and differential pinion shaft to rotate together with the differential case 7, which then rotates the differential side gear connected to the drive shaft 106, and the driving force is transmitted to the drive shaft 106.

[0036] The differential pinion can rotate on its own axis as well as revolve together with the differential case 7. When the left and right drive wheels receive equal resistance from the road surface while traveling straight ahead, the differential pinion revolves together with the differential case 7, transmitting driving force to the differential side gears. In this case, the differential pinion does not rotate on its own axis.

[0037] The differential pinion rotates while revolving when there is a difference in the resistance that the left and right wheels 103 receive from the road surface. The rotation of the differential pinion causes a difference in rotational speed between the left and right differential side gears, so the difference in rotational speed between the left and right wheels 103 is absorbed.

[0038] <Differential Case 7> The differential case 7 houses the distribution mechanism 6 and transmits the driving force of the ring gear 5 to the distribution mechanism 6. The distribution mechanism 6 and the ring gear 5 are arranged on either side of the rotation shaft (rotation center axis O) of the motor 2. The differential case 7 is a cylindrical member that surrounds the distribution mechanism 6 and the two drive shafts 106.

[0039] The differential case 7 has a large cylinder portion 71 and a small cylinder portion 72. The large cylinder portion 71 is a cylindrical member that covers the distribution mechanism 6. The small cylinder portion 72 is a cylindrical member that has a smaller diameter than the large cylinder portion 71 and connects the toothless inner peripheral surface portion 52 of the ring gear 5 to the large cylinder portion 71. As a result, the bevel gear 4 is disposed in a space surrounded by the ring gear 5, the large cylinder portion 71, and the small cylinder portion 72.

[0040] <Differential housing 8> The differential housing 8 is open on the upper side in the motor axial direction, which is the upward direction U, and covers the differential case 7. The opening of the differential housing 8 is covered by a housing 25.

[0041] <Motor 2 details> <Connection 22> The connecting part 22 connects the gear shaft 41 and the rotor 24 at the axial center of the rotor 24. The connecting part 22 is disk-shaped and has a hole formed in its center. The inner diameter end of the connecting part 22 is connected to the gear shaft 41 that is passed through the hole.

[0042] The connecting portion 22, together with the rotor cylindrical portion 24a, is made of a material that is difficult to deform (a material with a large Young's modulus), such as metal or carbon fiber composite resin. The connecting portion 22 is disk-shaped, which increases the radial rigidity and functions as a rib to prevent radial deformation, as well as transmitting rotation.

[0043] <Stator 23> The stator 23 has a cylindrical shape that is longer in the radial direction, which is a lateral direction including a front direction F, a rear direction B, a right direction R, and a left direction L, than in the axial direction.

[0044] The stator 23 is manufactured by laminating electromagnetic steel sheets. Because the stator 23 has a large-diameter cylindrical shape, split cores offer better material yields. However, it is difficult to consider a support structure for the stator 23 that can withstand large torque. With an integrated core, material yields are poor when considered alone, but yields can be improved by punching out the rotor 24 or cores for other products from the remaining disk portion on the inner periphery of the stator core. The stator 23 has higher rigidity when connected to a cylinder, making structural design easier than with split cores. The stator 23 can be either concentrated winding or split winding, but concentrated winding is more advantageous because of its large diameter and split winding, which increases the coil length.

[0045] <Rotor 24> The rotor 24 is a cylindrical member that faces the stator 23 in the radial direction. The rotor 24 is disposed on the inner peripheral side of the stator 23. In other words, the rotor 24 is a cylindrical member that is disposed on the inner diameter side of the stator 23 and faces the stator 23.

[0046] The rotor 24 has a cylindrical rotor portion 24a, a rotor core 24b arranged circumferentially around the rotor cylindrical portion 24a, and multiple magnetic poles arranged on the rotor core 24b. The rotor 24 is manufactured by laminating electromagnetic steel sheets, similar to the stator 23. Because the rotor 24 has a large-diameter cylindrical shape, a split core improves material yield. However, it is difficult to consider a support structure for the rotor 24 that can withstand large torque. The rotor 24 is an inner rotor arranged on the inner periphery of the stator 23, but it may also be an outer rotor. Furthermore, the rotor 24 may be an induction motor or a permanent magnet motor, and the type of rotor 24 is not limited. The rotor 24 here is a permanent magnet synchronous motor.

[0047] <Housing 25> The housing 25 houses the stator 23 and the rotor 24. The housing 25 houses the gear shaft 41, the stator 23, the rotor 24, and the connection portion 22, and has a lower end of the gear shaft 41 in the axial direction protruding downward in the direction D. The housing 25 has an H-shaped longitudinal cross section.

[0048] The housing 25 is composed of an upper half 25a and a lower half 25b. The upper half 25a is a lid-like member that covers the box-shaped lower half 25b that is open in the upward direction U and holds the stator 23 and the rotor 24. In order to hold the stator 23 and the rotor 24, the lower half 25b is formed so that its axial upper end is higher than the axial upper ends of the stator 23 and the rotor 24.

[0049] The outer peripheral lower surface 25c of the housing 25 is disposed at a position overlapping at least a part of the distribution mechanism 6 when viewed from a direction perpendicular to the rotation axis (rotation center axis O) of the motor 2. The outer peripheral lower surface 25c of the housing 25 refers to the surface of the housing 25 located at the lowest side (the drive shaft 106 side).

[0050] The housing 25 is a housing that supports the stator 23, the rotor 24, bearings, etc., and is connected to the chassis 101. A first recess 27a that is recessed upward is formed in the lower surface of the housing 25. By storing the differential case 7 in this first recess 27a, the height of the entire drive unit 1 is reduced. A second recess 27b that is recessed downward is formed in the upper surface of the housing 25. Electrical components such as the inverter 3 are stored in this second recess 27b. Because the cylindrical stator 23, when used alone as a core, will deform in the radial direction, the housing 25 needs to have rigidity to suppress deformation of the stator 23.

[0051] To reduce weight, it is desirable to use a light metal such as aluminum or a magnesium alloy for the housing 25. In a structure in which the housing 25 is provided with reinforcing materials such as ribs to increase rigidity, aluminum, which has a high specific strength (strength per unit weight), is well suited.

[0052] The housing 25 may be air-cooled, but to achieve high power density, a liquid refrigerant flow path is provided inside the housing 25. The housing 25 is configured to cool the motor 2 with a liquid refrigerant such as mineral oil or ATF, and the liquid refrigerant after cooling the motor 2 is also circulated through the distribution mechanism 6 to cool the various gears.

[0053] <Rotor core 24b> The rotor core 24b is cylindrical and is longer in the radial direction, which is a horizontal direction including the front direction F, the rear direction B, the right direction R, and the left direction L, than in the axial direction. The rotor core 24b is made by laminating electromagnetic steel sheets. The rotor core 24b is made up of multiple magnetic core plates laminated in the axial direction, which extend in a direction perpendicular to the central axis extending vertically.

[0054] <Rotor cylindrical portion 24a> The rotor cylindrical portion 24a supports the rotor 24 and is rotatably supported by the housing 25 via bearings 30. The rotor cylindrical portion 24a is a cylindrical member. The rotor cylindrical portion 24a extends in the axial direction. The rotor cylindrical portion 24a holds the rotor core 24b from its inner peripheral side. The connecting portion 22 is connected to the axial center of the rotor cylindrical portion 24a.

[0055] The inner diameter of the rotor cylindrical portion 24 a is larger than the outer diameter of the bevel gear 4 .

[0056] The rotor cylindrical portion 24a is defined as a rotating body equipped with bearings 30 for supporting the rotation of the rotor 24. In the illustrated example, the bearings 30 are provided on the upper and lower sides of the rotor core 24b, but they may be provided on only one of the upper and lower sides of the rotor core 24b. The rotor cylindrical portion 24a is connected to the gear shaft of the bevel gear 4 described above via a connecting portion 22. The material of the rotor cylindrical portion 24a may be carbon steel, stainless steel, or a light metal such as aluminum depending on the size.

[0057] Because the rotor 24 has a large-diameter cylindrical shape, it requires radially extending ribs to prevent radial deformation. The rotor cylindrical portion 24a functions as both a rotation transmission mechanism and a rib to prevent radial deformation. The rotor 24 may be configured such that the rotor cylindrical portion 24a and the rotor core 24b are connected together, or the rotor core 24b may be attached to the rotor cylindrical portion 24a made of aluminum or the like to prevent radial deformation of the rotor core 24b.

[0058] <First recess 27a and second recess 27b> A pair of first and second recesses 27a and 27b recessed in the axial direction are formed on both axial sides of the housing 25 on the radially inner side of the rotor 24.

[0059] The first recess 27a, which is one of the pair of first recesses 27a and second recesses 27b, is formed on the axially lower side of the housing 25 by recessing the lower surface of the housing 25 in the upward direction U to fit the rotor cylindrical portion 24a and the connection portion 22, which have an H-shaped cross section. The distribution mechanism 6 is disposed in the first recess 27a. More specifically, the bevel gear 4, part of the ring gear 5, part of the distribution mechanism 6, and part of the differential case 7 are housed in the first recess 27a.

[0060] The second recess 27b, which is the other of the pair of first recess 27a and second recess 27b, is formed on the axially upper side of the housing 25 by recessing the upper surface of the housing 25 in the downward direction D to fit the rotor cylindrical portion 24a and the connection portion 22, which have an H-shaped cross section. The inverter 3 is disposed in the second recess 27b. More specifically, the inverter 3 is completely housed within the second recess 27b. The axially upper end of the gear shaft 41 protrudes partway through the axial depth of the second recess 27b.

[0061] <Motor cooling structure> Next, a description will be given of the cooling structure of the motor 2. Fig. 6A is an enlarged perspective view of a cross section of the motor according to the first embodiment of the present invention, with the rotor removed. Fig. 6B is an enlarged view of part VIB in Fig. 6A.

[0062] The stator core 23a includes a cylindrical core back portion 23a1 on the radially outer side of the stator core 23a, a plurality of teeth 23c protruding radially inward from the core back portion 23a1, and a plurality of slots 23d formed between the plurality of teeth 23c. A coil 23b is inserted into each of the plurality of slots 23d. The radially inner (rotor side) end of the coil 23b is positioned radially outward from the radially inner (rotor side) end of the tooth 23c. In other words, with the coil 23b inserted, the slot 23d is recessed radially outward from the radially inner (rotor side) end of the tooth 23c.

[0063] The upper half 25a of the housing 25 is provided with an upper passageway formation body 251 that extends downward so as to contact the upper portions of the teeth 23c of the stator core 23a. The upper passageway formation body 251 connects the housing 25 and the upper end surface of the stator core 23a on the gap G side, and is formed in an annular shape inside the housing 25. An upper passageway 252 is formed above the stator core 23a (coils 23b) by the housing 25, the upper end surface of the stator core 23a, and the upper passageway formation body 251. The upper passageway 252 is formed in an annular shape inside the housing 25.

[0064] A plurality of refrigerant outlets 253 are arranged above slot 23d, and communicate with upper flow passage 252. Refrigerant outlets 253 are formed by upper flow passage formation body 251, teeth 23c, and slot 23d.

[0065] The lower half 25b of the housing 25 is provided with a lower-side passage-forming body 254 that extends upward so as to contact the lower portions of the teeth 23c of the stator core 23a. The lower-side passage-forming body 254 connects the housing 25 and the lower end surface of the stator core 23a on the gap G side, and is formed in an annular shape inside the housing 25. A lower passage 255 is formed below the stator core 23a (coils 23b) by the housing 25, the lower end surface of the stator core 23a, and the lower-side passage-forming body 254. The lower-side passage 255 is formed in an annular shape inside the housing 25.

[0066] A plurality of refrigerant receiving ports 256 are arranged below the slots 23d, and communicate with the lower flow passages 255. The refrigerant receiving ports 256 are formed by the lower flow passage formation body 254, the teeth 23c, and the slots 23d.

[0067] 6A, a slot flow path 257 is formed inside slot 23d (on the rotor side), connecting upper flow path 252 and lower flow path 255 via refrigerant outlet 253 and refrigerant inlet 256. At least a portion of the end face of slot flow path 257 on the gap G side with rotor core 24b is open.

[0068] The cross-sectional area of ​​the upper flow passage 252 in a direction perpendicular to the rotation axis is larger than the sum of the cross-sectional areas of the multiple slot flow passages 257 in a direction perpendicular to the rotation axis. This allows the liquid refrigerant to be ejected from the multiple slot flow passages 257 in a balanced manner.

[0069] Next, the flow of liquid refrigerant will be described with reference to Figures 7 and 8. Figure 7 is a schematic cross-sectional view of a portion of a motor according to a first embodiment of the present invention. Figure 8 is a schematic view showing the flow of liquid refrigerant according to the first embodiment of the present invention. A flow path inlet 258 communicating with the upper flow path 252 is formed in the upper part of the housing 25. A flow path outlet 259 communicating with the lower flow path 255 is formed in the lower part of the housing 25. The flow path inlet 258 and the flow path outlet 259 are connected to an oil cooler (not shown) via piping, and the liquid refrigerant is pressure-fed to the motor 2 by driving a refrigerant pump.

[0070] In this embodiment, the rotation axis of the rotor shaft 26 is arranged so as to be aligned vertically. Liquid refrigerant pumped by the refrigerant pump flows into the upper flow passage 252 from the flow passage inlet 258, then branches left and right and flows through the upper flow passage 252. The liquid refrigerant flowing through the upper flow passage 252 falls due to gravity from the multiple refrigerant outlets 253, and flows downward within the slot flow passage 257 along the surface of the coil 23b due to surface tension. The liquid refrigerant flowing through the slot flow passage 257 comes into contact with the surface of the coil 23b and absorbs heat from the coil 23b. As a result, the coil 23b is cooled by the liquid refrigerant.

[0071] The liquid refrigerant that has cooled the coil 23b flows from the refrigerant receiving port 256 into the lower flow path 255 and is discharged to the outside of the motor 2 from a flow path outlet 259 that communicates with the lower flow path 255. The discharged liquid refrigerant is cooled by the oil cooler and flows toward the upper flow path 252 again.

[0072] In this embodiment, the liquid refrigerant that flows into the upper flow passage 252 from the flow passage inlet 258 is branched to flow in the left and right directions, and the liquid refrigerant collides on the radially opposite side of the flow passage inlet 258. By branching the refrigerant to flow in the left and right directions in this manner, it is possible to suppress variations in the flow rate of the liquid refrigerant flowing through the slot flow passage 257. Also, in this embodiment, the flow passage outlet 259 is disposed 180° away from the flow passage inlet 258. With this configuration, it is possible to uniform the entire flow passage length including the slot flow passage 257.

[0073] The liquid refrigerant flowing through the upper flow passage 252 may not branch to the left and right, but may flow in one direction to make a full circuit of the upper flow passage 252. In this case, although the flow rate of the slot flow passage varies, the flow velocity of the liquid refrigerant increases, thereby improving cooling performance.

[0074] In addition, in this embodiment, the lower flow path 255 is formed by the lower flow path forming body 254, but the lower flow path 255 may not be provided and the liquid refrigerant may be directly collected, for example, like an oil pan.

[0075] Furthermore, in this embodiment, the rotation axis of the motor 2 (rotor shaft 26) is arranged along the vertical direction, but it may be arranged so as to be tilted from the vertical state. In other words, the rotation axis of the rotor shaft may be arranged at a predetermined angle with respect to the horizontal axis.

[0076] If the rotation axis of the motor 2 (rotor shaft 26) is tilted from the vertical direction, as the slot flow path 257 approaches horizontal, gravity overcomes the force of surface tension that tries to keep the refrigerant in the slot 23d, causing it to drip toward the rotor 24. As a result, the liquid refrigerant will come into contact with the rotor, slightly increasing fluid friction loss and reducing heat dissipation from the coil, but the tilt angle can be large as long as it remains at a level that does not affect performance.

[0077] Next, the effects of the present invention will be described. Fig. 9 is a schematic view of a portion of a motor 2 according to a comparative example, viewed from the axial direction. Fig. 10 is a schematic view of a portion of a motor 2 according to Example 1 of the present invention, viewed from the axial direction. For convenience, in Figs. 9 and 10, the stator 23 and the rotor 24 are depicted as straight lines.

[0078] A plurality of magnets 24c are arranged in the rotor core 24b of the rotor 24. The coils 23b arranged in the slots 23d generate heat when a current flows through them. The temperature distribution of the generated heat is such that the temperature is higher on the rotor 24 side (radially inner side) and decreases toward the opposite rotor side (radially outer side). When cooling the coils 23b, it is preferable to actively cool the rotor 24 side (radially inner side) where the temperature is higher. In the comparative example shown in FIG. 9, the housing 25 is filled with a liquid refrigerant. A gap G is provided between the stator 23 and the rotor 24, and the liquid refrigerant also flows into this gap G. The coils 23b are cooled by dissipating heat toward the liquid refrigerant in the gap G. Furthermore, the magnets of the rotor 24 generate heat due to the generation of eddy currents, but the heat is dissipated toward the liquid refrigerant in the gap G and is cooled. In the comparative example, the stator 23 and the rotor 24 are cooled by the liquid refrigerant in which they are immersed. However, in the comparative example, when rotor 24 rotates, it rotates while coming into contact with the liquid refrigerant in gap G, and the liquid refrigerant in gap G creates rotational resistance, causing fluid friction loss. As a result, rotor 24 in the comparative example is subjected to fluid friction loss, resulting in reduced motor efficiency.

[0079] On the other hand, in this embodiment, the presence of liquid refrigerant in the gap G between the stator 23 and the rotor 24 can be reduced, thereby reducing fluid friction loss when the rotor 24 rotates. Also, in this embodiment, the liquid refrigerant is caused to flow through the slot flow passage 257 located on the rotor 24 side where the heat generation of the coil 23b is the highest, thereby suppressing a decrease in motor efficiency and efficiently cooling the coil 23b. Although a rectangular coil is used in this embodiment, the coil may be round, and any type of coil is acceptable. Furthermore, the coil may be concentrated winding or distributed winding.

[0080] According to this embodiment, it is possible to provide a rotating electrical machine in which the cooling structure is simplified and an increase in production costs is suppressed. [Example]

[0081] Next, a second embodiment of the present invention will be described with reference to Figs. 11 to 13. Fig. 11 is an enlarged perspective view of a cross section of a motor according to the second embodiment of the present invention, with the rotor removed. Fig. 12 is a schematic cross-sectional view of a portion of the motor according to the second embodiment of the present invention. Fig. 13 is a schematic view showing the flow of liquid refrigerant according to the second embodiment of the present invention. Components common to the first embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0082] In the second embodiment, the position of the flow path inlet 258 is different from that in the first embodiment.

[0083] As shown in Figures 12 and 13, a flow path inlet 258 is formed in the center of the housing 25 in the axial direction (vertical direction). In addition, an annular flow path 260 is formed between the stator core 23a and the housing 25. The annular flow path 260 is formed along the entire circumferential circumference of the stator core 23a. A side flow path 261 extending upward is formed between the stator core 23a and the housing 25. The side flow path 261 is located on the radially opposite side (180°) of the flow path inlet 258, and is in communication with the annular flow path 260 and the upper flow path 252.

[0084] A refrigerant collecting section 262 in which liquid refrigerant accumulates is provided at the bottom of the housing 25. A communication port 263 is formed by cutting out a portion of the lower flow path forming body 254. In this embodiment, the flow path outlet 259 is disposed so as to be shifted radially opposite (180°) from the flow path inlet 258.

[0085] The motor 2 is disposed so that its rotation axis is aligned vertically. Liquid refrigerant pumped by the refrigerant pump flows into the annular flow path 260 from the flow path inlet 258, branches left and right, and merges on the radially opposite side. The merged liquid refrigerant rises through the side flow path 261, flows into the upper flow path 252, and then branches left and right to flow through the upper flow path 252. The liquid refrigerant flowing through the upper flow path 252 falls due to gravity from multiple refrigerant outlets 253 and flows downward within the slot flow path 257 along the surface of the coil 23b due to surface tension. The liquid refrigerant flowing through the slot flow path 257 comes into contact with the surface of the coil 23b and removes heat from the coil 23b. The coil 23b is cooled by the liquid refrigerant.

[0086] After cooling the coil 23b, the liquid refrigerant accumulates in a refrigerant collection section 262 (lower flow path 255) below the motor 2, passes through a communication port 263 formed in the lower flow path formation body 254, and flows into the lower coil end flow path 255a (lower flow path 255). The communication port 263 is on the same side as the flow path inlet 258. The liquid refrigerant that flows into the lower coil end flow path 255a (lower flow path 255) splits in the left and right directions and merges on opposite radial sides. The merged liquid refrigerant is discharged outside the motor 2 from a flow path outlet 259 that communicates with the lower coil end flow path 255a (lower flow path 255). The discharged liquid refrigerant is cooled in an oil cooler and flows again toward the annular flow path 260.

[0087] In this embodiment, the liquid refrigerant flowing through the annular flow path 260 flows in the opposite direction to the liquid refrigerant flowing through the upper flow path 252. The liquid refrigerant becomes hotter as it moves away from the inlet due to heat transfer from heat-generating components. Therefore, in this embodiment, the flow directions of the liquid refrigerant flowing through the annular flow path 260 and the upper flow path 252 are reversed, thereby making it possible to uniform the average temperature of the stator core 23a and the coils 23b as a whole. [Example]

[0088] Next, a third embodiment of the present invention will be described with reference to Figs. 11, 14, and 15. Fig. 14 is a schematic cross-sectional view of a part of a motor according to the third embodiment of the present invention. Fig. 15 is a schematic view showing the flow of a liquid refrigerant according to the third embodiment of the present invention. The same components as those in the first and second embodiments are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0089] The third embodiment differs from the first and second embodiments in that the liquid refrigerant discharged from the annular flow path 260 branches off into upper and lower flows. In addition, the lower flow path 255 is made up of a lower coil end flow path 255a and a refrigerant collecting portion 262.

[0090] As shown in FIGS. 14 and 15 , a flow path inlet 258 is formed in the axial (vertical) center of the housing 25. An annular flow path 260 is formed between the stator core 23a and the housing 25. The annular flow path 260 is formed along the entire circumferential circumference of the stator core 23a. An upper side flow path 264 extending upward and a lower side flow path 265 extending downward are formed between the stator core 23a and the housing 25. The upper side flow path 264 and the lower side flow path 265 are located on radially opposite sides (180°) of the flow path inlet 258. The upper side flow path 264 communicates with the annular flow path 260 and the upper flow path 252, and the lower side flow path 265 communicates with the annular flow path 260 and the lower coil end flow path 255a (lower flow path 255). In other words, the upper side flow path 264 and the lower side flow path 265 branch off the annular flow path 260 in the vertical direction.

[0091] The lower part of the housing 25 is provided with a refrigerant collecting section 262 (lower flow path 255) in which liquid refrigerant accumulates, and an oil pan 266 that hangs down from the refrigerant collecting section 262. In this embodiment, the positions of the upper side flow path 264 and the lower side flow path 265 are shifted radially opposite (180°) from the flow path inlet 258.

[0092] The rotation axis of the motor 2 (rotor shaft 26) is arranged along the vertical direction. The liquid refrigerant pumped flows into the annular flow path 260 from the flow path inlet 258, branches into the left and right directions, and merges on the radially opposite side.

[0093] A portion of the merged liquid refrigerant rises in the upper side flow passage 264, flows into the upper flow passage 252, and then splits into left and right parts that flow through the upper flow passage 252. The liquid refrigerant flowing through the upper flow passage 252 falls due to gravity from the multiple refrigerant outlets 253 and flows downward within the slot flow passage 257 along the surface of the coil 23b due to surface tension. The liquid refrigerant flowing through the slot flow passage 257 comes into contact with the surface of the coil 23b and removes heat from the coil 23b. The coil 23b is cooled by the liquid refrigerant.

[0094] Furthermore, part of the merged liquid refrigerant flows downward in the side downstream flow passage 265, flows into the lower coil end flow passage 255a (lower flow passage 255), and then splits into left and right parts that flow through the lower coil end flow passage 255a. The liquid refrigerant flowing through the lower coil end flow passage 255a is pressure-fed by the refrigerant pump, so that the liquid refrigerant sprays out from the gap between the lower flow passage formation member 254 and the slot flow passage 257 and flows into the refrigerant collection section 262. Furthermore, the liquid refrigerant flowing through the lower coil end flow passage 255a cools the lower part of the coil 23b.

[0095] The liquid refrigerant that has flowed into the refrigerant collecting portion 262 accumulates in the oil pan 266 and is discharged to the outside of the motor 2 from the flow path outlet 259 that communicates with the oil pan 266. The discharged liquid refrigerant is cooled by the oil cooler and flows again toward the annular flow path 260.

[0096] When the rotor 24 is rotating and the liquid refrigerant is circulating inside the motor 2, the liquid level L1 of the liquid refrigerant accumulated in the refrigerant collecting portion 262 (lower flow path 255) is set to be lower than the bottom surface position L2 of the rotor core 24b. This prevents the rotor core 24b from coming into contact with the liquid refrigerant, thereby reducing fluid friction loss.

[0097] In this embodiment, the liquid refrigerant pumped by the refrigerant pump is branched in the vertical direction of the stator core 23a and pumped to the upper flow path 252 and the lower flow path 255, thereby increasing the flow rate through the upper flow path 252 and the lower flow path 255 and improving the cooling efficiency. [Example]

[0098] Next, a fourth embodiment of the present invention will be described with reference to Figs. 16 to 19. Fig. 16 is a perspective view of a drive unit 1 according to the fourth embodiment of the present invention, cut in half at a longitudinal section. Fig. 17 is a cross-sectional view of the drive unit 1 according to the fourth embodiment of the present invention, as seen from the drive shaft 106 side. Fig. 18 is a cross-sectional view of the drive unit 1 when the vehicle is decelerating or descending a slope. Fig. 19 is a cross-sectional view of the drive unit 1 when the vehicle is accelerating or ascending a slope.

[0099] The same reference numerals are used to designate the same components as those in the first to third embodiments, and detailed descriptions thereof will be omitted. Figures 16 to 19 show a drive device for a vehicle.

[0100] In this embodiment, the ring gear 5 is directly fastened to the differential case 7. Therefore, the ring gear 5 and the distribution mechanism 6 are arranged radially side by side on one side of the rotation shaft (rotation center axis O) of the motor 2.

[0101] The ring gear 5 is disposed with its center of rotation facing inward in the right direction R, which is the side of the rotation shaft (rotation center axis O) of the motor 2. The ring gear 5 has a gear tooth surface portion 51 that faces the right direction R and has gear teeth at a predetermined taper angle, and a radial back surface portion 53 that is provided on the left direction L side of the gear tooth surface portion 51. The radial back surface portion 53 does not have the teeth of the ring gear 5, and is connected to the large cylinder portion 71.

[0102] The large cylindrical portion 71 of the differential case 7 is connected to the toothless radial back surface portion 53 of the ring gear 5 and covers the distribution mechanism 6 .

[0103] Further, the drive unit 1 of this embodiment is provided with an oil pan 266, similar to the third embodiment. The oil pan 266 and the distribution mechanism 6 are disposed adjacent to each other.

[0104] The differential case 7 is filled with differential oil. At low temperatures, differential oil has low viscosity and high friction loss. The hottest liquid refrigerant collects in the oil pan 266 after absorbing heat from the motor 2. Therefore, by arranging the oil pan 266 adjacent to the distribution mechanism 6 including the differential case 7, the heat of the liquid refrigerant is transferred to the differential oil. In this embodiment, the oil pan 266 and the distribution mechanism 6 are arranged adjacent to each other, so the differential oil can be warmed and friction loss in the distribution mechanism 6 can be reduced. Furthermore, in this embodiment, the liquid refrigerant can exchange heat with the distribution mechanism 6, so the liquid refrigerant can be cooled, thereby improving the cooling efficiency of the motor 2.

[0105] In this embodiment, the oil pan 266 adjacent to the distribution mechanism 6 is arranged rearward of the vehicle body from the center of the motor 2. While traveling, the vehicle 100 accelerates, decelerates, climbs, and descends slopes depending on the road and traffic environment.

[0106] For example, as shown in Figure 18, when the vehicle 100 is decelerating and going downhill, the front of the vehicle body sinks and tilts forward, causing the drive unit 1 to also tilt forward. Because liquid refrigerant flows through the motor 2 of the drive unit 1, the liquid refrigerant also shifts to the front side in response to the forward tilt of the drive unit 1 so as not to exceed the liquid level h. The rotor core 24b located at the front is immersed in the liquid refrigerant that has shifted to the front, resulting in increased flow path friction loss. According to this embodiment, when the vehicle 100 is decelerating and going downhill, braking action can be achieved by utilizing the flow path friction loss of the rotor core 24b, thereby cooling the motor 2 and reducing brake pad wear.

[0107] On the other hand, for example, when the vehicle 100 is accelerating or climbing a slope, as shown in FIG. 19, the rear of the vehicle body tilts backward, causing the drive unit 1 to also tilt backward. Because liquid refrigerant flows through the motor 2 of the drive unit 1, the liquid refrigerant also shifts to the rear side in response to the rearward tilt of the drive unit 1 so as not to exceed the liquid level h. Because the oil pan 266 is located rearward of the center of the motor 2, the liquid refrigerant remains in the oil pan 266, preventing it from flowing into the rotor core 24b and reducing flow path friction loss. When the vehicle 100 is accelerating or climbing a slope, the torque of the motor 2 needs to be increased.

[0108] According to this embodiment, when the vehicle 100 is accelerating or climbing, the fluid friction loss generated by the liquid refrigerant coming into contact with the rotor core 24b can be reduced, thereby improving the acceleration performance and climbing performance of the vehicle 100.

[0109] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0110] 1... drive device, 2... motor, 3... inverter, 4... bevel gear, 5... ring gear, 6... distribution mechanism, 7... differential case, 8... differential housing, 22... connection portion, 23... stator, 23a... stator core, 23a1... core back portion, 23b... coil, 23c... teeth, 23d... slot, 24... rotor, 24a... rotor cylindrical portion, 24b... rotor core, 25... housing, 25a... upper half, 25b... lower half, 25c... outer periphery underside, 26... rotor shaft, 27a... first recess, 27b... second recess, 30... bearing, 41... gear shaft, 51... gear tooth surface portion, 52... inner periphery surface portion, 7 1...large cylindrical portion, 72...small cylindrical portion, 100...vehicle, 101...chassis, 102...support member, 103...wheel, 104...wheel, 105...battery, 106...drive shaft, 251...upper flow passage forming body, 252...upper flow passage, 253...refrigerant outlet, 254...lower flow passage forming body, 255...lower flow passage, 255a...lower coil end flow passage, 256...refrigerant receiving port, 257...slot flow passage, 258...flow passage inlet, 259...flow passage outlet, 260...annular flow passage, 261...side flow passage, 262...refrigerant collecting portion, 263...communication port, 264...upper side flow passage, 265...lower side flow passage, 266...oil pan

Claims

1. A rotating electric machine comprising: a cylindrical stator core having a plurality of slots in which coils are fitted; a rotor core that faces the stator core in a radial direction of the stator core with a predetermined gap therebetween; a rotor shaft that rotates together with the rotor core; and a housing that stores the stator core, the rotor core, and the rotor shaft, The rotation axis of the rotor shaft is disposed at a predetermined angle with respect to a horizontal axis, an upper flow passage formed above the stator core and through which a liquid refrigerant flows; a lower flow passage formed below the stator core; and a slot flow passage communicating between the upper flow passage and the lower flow passage, the upper flow passage is formed by the housing, an upper end surface of the stator core, and an upper flow passage formation member that connects the housing and an upper end surface of the stator core on the gap side, The rotating electric machine is characterized in that at least a part of the end surface of the slot flow passage on the gap side is open.

2. 2. The rotating electric machine according to claim 1, A rotating electric machine characterized in that the rotation shaft is arranged in a vertical direction.

3. 2. The rotating electric machine according to claim 1, A rotating electric machine, characterized in that the cross-sectional area of ​​the upper flow passage is larger than the total cross-sectional area of ​​the slot flow passages.

4. 2. The rotating electric machine according to claim 1, the lower flow path is composed of a lower coil end flow path through which the liquid refrigerant is pressure-fed and a refrigerant collection section where the liquid refrigerant is not pressure-fed, The liquid refrigerant is branched and pressure-fed to the upper flow passage and the lower coil end flow passage.

5. 2. The rotating electric machine according to claim 1, an annular flow passage between the housing and the stator core; A rotating electric machine, characterized in that a liquid refrigerant flows in the annular flow path in a direction opposite to that of the upper flow path.

6. 5. The rotating electric machine according to claim 4, a liquid level of the refrigerant collecting portion being lower than a bottom surface of the rotor core;

7. A vehicle drive device comprising the rotating electric machine according to any one of claims 1 to 6.

8. 8. The drive device according to claim 7, an oil pan disposed below the lower flow path; and a distribution mechanism that transmits driving force of the rotating electric machine to an axle, A vehicle drive system, wherein the oil pan and the distribution mechanism are disposed adjacent to each other.

9. 9. The drive device according to claim 8, The vehicle drive device is characterized in that the oil pan is disposed rearward of the center of the rotating electric machine on the vehicle body.

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