CN111756175B - Driving device - Google Patents

Driving device Download PDF

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Publication number
CN111756175B
CN111756175B CN202010102075.6A CN202010102075A CN111756175B CN 111756175 B CN111756175 B CN 111756175B CN 202010102075 A CN202010102075 A CN 202010102075A CN 111756175 B CN111756175 B CN 111756175B
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CN
China
Prior art keywords
axial
motor
rotor
fan
core
Prior art date
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Application number
CN202010102075.6A
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Chinese (zh)
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CN111756175A (en
Inventor
竹本心路
小笠原大介
松田和敏
矶贝悠介
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Nidec Corp
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Nidec Corp
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Publication of CN111756175A publication Critical patent/CN111756175A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K9/00—Arrangements for cooling or ventilating
    • H02K9/02—Arrangements for cooling or ventilating by ambient air flowing through the machine
    • H02K9/04—Arrangements for cooling or ventilating by ambient air flowing through the machine having means for generating a flow of cooling medium
    • H02K9/06—Arrangements for cooling or ventilating by ambient air flowing through the machine having means for generating a flow of cooling medium with fans or impellers driven by the machine shaft
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/10—Casings or enclosures characterised by the shape, form or construction thereof with arrangements for protection from ingress, e.g. water or fingers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/003—Couplings; Details of shafts
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/006—Structural association of a motor or generator with the drive train of a motor vehicle
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
    • H02K7/116—Structural association with clutches, brakes, gears, pulleys or mechanical starters with gears
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/64—Electric machine technologies in electromobility

Abstract

The invention provides a driving device. One embodiment of the driving device of the present invention includes: a motor including a rotor rotatable about a central axis, a stator facing the rotor with a gap therebetween, and a 1 st housing accommodating the rotor and the stator therein; a 2 nd casing accommodating the motor therein; and at least one fan, the at least one fan is arranged on the rotor in the 1 st shell.

Description

Driving device
Technical Field
The present invention relates to a driving device.
Background
It is known that a motor having a housing further accommodates drive means inside other housings. For example, patent document 1 describes a structure in which a motor is accommodated in a hub of a wheel.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 2000-83049
Disclosure of Invention
Problems to be solved by the invention
In the driving device described above, since the motor is housed in the other casing, there is a problem in that it is difficult to discharge heat of the motor to the outside.
In view of the above, an object of the present invention is to provide a driving device having a structure capable of improving heat dissipation of a motor.
Means for solving the problems
One embodiment of the driving device of the present invention includes: a motor including a rotor rotatable about a central axis, a stator facing the rotor with a gap therebetween, and a 1 st housing accommodating the rotor and the stator therein; a 2 nd casing accommodating the motor therein; and at least one fan arranged in the rotor in the 1 st casing.
Effects of the invention
According to one aspect of the present invention, the heat dissipation of the motor can be improved in the driving device.
Drawings
Fig. 1 is a perspective view showing a driving device according to embodiment 1.
Fig. 2 is a cross-sectional view showing the drive device of embodiment 1, and is a cross-sectional view taken along line II-II in fig. 1.
Fig. 3 is a perspective view showing a part of the rotor of embodiment 1.
Fig. 4 is a perspective view of the motor of embodiment 1 viewed in one direction.
Fig. 5 is a perspective view of the motor of embodiment 1 viewed in the other direction.
Fig. 6 is a cross-sectional view showing a part of the drive device of embodiment 1.
Fig. 7 is a cross-sectional view showing a part of the drive device according to embodiment 2.
Fig. 8 is a perspective view showing a part of the rotor of embodiment 2.
Description of the reference numerals
1. 2: a driving device; 10. 110: a motor (in-wheel motor); 30: hub (2 nd housing); 50. 150: a rotor; 52: a rotor core; 55: a core penetration portion; 60: a stator; 70. 170: a motor case (1 st case); 70a: a vent hole portion; 70b: an axial hole portion; 70c: a radial hole portion; 73: 1 st axial wall portion (axial wall portion); 73a: a 1 st axial hole portion; 74: a 1 st peripheral wall portion (peripheral wall portion); 76: a 2 nd axial wall portion (axial wall portion); 76a: a 2 nd axial hole portion; 77: a 2 nd peripheral wall portion (peripheral wall portion); 80. 180: a fan; 81. 82: a centrifugal fan; 181: an axial flow fan; 182: a suction fan; j: a central axis.
Detailed Description
The X-axis direction appropriately shown in each drawing is a horizontal direction perpendicular to the vertical direction. The vertical direction in each drawing is the vertical direction. In the following embodiments, the X-axis direction is the left-right direction of a vehicle on which the drive device of each embodiment is mounted. The central axis J appropriately shown in each figure is a virtual line extending in a direction parallel to the X-axis direction which is the left-right direction. In the following description, the axial direction of the central axis J, that is, the direction parallel to the X-axis direction is simply referred to as "axial direction", the positive side in the X-axis direction is referred to as "right side", and the negative side in the X-axis direction is referred to as "left side". The radial direction centered on the central axis J is simply referred to as "radial direction", and the circumferential direction centered on the central axis J is simply referred to as "circumferential direction".
In the following embodiments, the right side corresponds to one axial side, and the left side corresponds to the other axial side. The vertical direction, the horizontal direction, the left-right direction, the right side, and the left side are only names used for explaining the relative positional relationship of the respective parts, and the actual arrangement relationship and the like may be other than the arrangement relationship and the like shown by these names.
Embodiment 1
The drive device 1 of the present embodiment shown in fig. 1 and 2 is used as a drive device for an electric vehicle such as an electric bicycle, an electric power assisted bicycle, or a walking assist vehicle. As shown in fig. 1 and 2, the driving device 1 includes: a pair of hub shafts 41, 42 fixed to the vehicle; a hollow hub 30 rotatable about hub shafts 41, 42; a motor 10 accommodated in the hub 30 and fixed to the hub shaft 41; and a reduction mechanism 20 connected to the motor 10 and the hub 30. In the present embodiment, the hub 30 corresponds to the 2 nd housing.
The hub shafts 41 and 42 have a columnar shape extending in the axial direction about the center axis J. The hub axle 41 protrudes from the hub 30 to the right. The hub axle 42 protrudes from the hub 30 to the left. As shown in fig. 2, the motor 10 has a motor housing 70 fixed to the hub axle 41. In the present embodiment, the reduction mechanism 20 is fixed to the motor housing 70. The hub axle 42, the reduction mechanism 20, the motor housing 70, and the hub axle 41 are connected and fixed in this order from the left side toward the right side in the axial direction. Further, either one of the hub shafts 41 and 42 may be fixed to the vehicle.
The hub 30 is rotatable about the central axis J. In the present embodiment, the hub 30 is driven to rotate about the hub shafts 41 and 42 by the driving force of the motor 10 and the reduction mechanism 20 fixed to the hub shafts 41 and 42. The hub 30 is a hollow outer casing that accommodates the motor 10 and the reduction mechanism 20 therein. In the present embodiment, the inside of the hub 30 is sealed. The hub 30 includes a bottom cylindrical body portion 31 and a disk-shaped cover portion 32.
In the present embodiment, the main body 31 has a cylindrical shape that is open to the left with the center axis J as the center. The main body 31 has a bottom wall 33 and a tube 34. The bottom wall portion 33 is located on the right side of the motor 10. The bottom wall portion 33 covers the motor 10 from the right side. A hub bearing 93 is held in a radially central portion of the bottom wall portion 33. The main body 31 is rotatably supported by the motor housing 70 via a hub bearing 93. The cylindrical portion 34 extends leftward from the radially outer peripheral edge portion of the bottom wall portion 33. The motor 10 and the reduction mechanism 20 are housed in this order from the bottom wall portion 33 to the left inside the tubular portion 34.
The cover 32 closes the opening of the main body 31 from the left side. The cover 32 is fixed to the main body 31 with, for example, screws. The cover 32 is located on the left side of the reduction mechanism 20. The cover 32 covers the reduction mechanism 20 from the left side. A hub bearing 94 is held in a radially central portion of the cover 32. The cover 32 is rotatably supported by the hub axle 42 via a hub bearing 94. As described above, in the present embodiment, the hub 30 is supported rotatably about the center axis J by the hub bearings 93 and 94. In the present embodiment, the hub bearings 93, 94 are rolling bearings. The hub bearings 93, 94 are, for example, ball bearings.
The motor 10 of the present embodiment is an in-wheel motor that rotates the wheel of the vehicle by rotating the hub 30. In the present embodiment, the motor 10 is an inner rotor type motor. The motor 10 has: a rotor 50 rotatable about a central axis J; a stator 60 facing the rotor 50 with a gap therebetween; and a motor case 70 accommodating the rotor 50 and the stator 60 therein. In the present embodiment, the motor case 70 corresponds to the 1 st casing.
The rotor 50 is rotatable about the central axis J. The rotor 50 has a motor shaft 51, a rotor core 52, a plurality of rotor magnets 54, and a molded resin portion 53. The motor shaft 51 is disposed along the central axis J. The motor shaft 51 has a cylindrical shape extending in the axial direction about the central axis J. The left end of the motor shaft 51 protrudes leftward from the motor housing 70. The motor shaft 51 is rotatably supported by bearings 91 and 92 held by the motor housing 70. In the present embodiment, the bearings 91, 92 are rolling bearings. The bearings 91, 92 are, for example, ball bearings.
The rotor core 52 is fixed to the outer peripheral surface of the motor shaft 51. Although not shown, the rotor core 52 is formed by stacking electromagnetic steel plates in the axial direction, for example. As shown in fig. 3, the rotor core 52 includes an inner core portion 52a, a plurality of outer core portions 52b, and a plurality of connecting portions 52c. The inner core portion 52a has an annular shape centered on the central axis J. The inner core portion 52a is fitted and fixed to the motor shaft 51. The plurality of outer core portions 52b are located radially outward of the inner core portion 52 a. The plurality of outer core portions 52b are arranged at intervals in the circumferential direction. In the present embodiment, the plurality of outer core portions 52b are arranged at equal intervals along the circumferential direction around the circumference. The number of the outer core portions 52b is 10, for example.
The plurality of connection portions 52c extend in the radial direction and connect each of the inner core portion 52a and the plurality of outer core portions 52 b. The plurality of connection portions 52c are arranged at intervals in the circumferential direction. In the present embodiment, the plurality of connection portions 52c are arranged at equal intervals along the circumferential direction. The plurality of connection portions 52c each have a hole portion 52d penetrating the connection portion 52c in the circumferential direction. The hole portion 52d is, for example, a rectangular hole.
Core penetrating portions 55 penetrating the rotor core 52 in the axial direction are provided between the circumferentially adjacent connecting portions 52c. That is, the rotor core 52 has a core penetration portion 55. A plurality of core penetration portions 55 are provided along the circumferential direction. In the present embodiment, the plurality of core through portions 55 are arranged at equal intervals along the circumferential direction. The core through portion 55 is connected to the inside of the hole 52d.
The plurality of rotor magnets 54 are disposed between the outer core portions 52b adjacent to each other in the circumferential direction. The circumferential side surfaces of the rotor magnet 54 are in contact with the circumferential side surfaces of the outer core portions 52b adjacent to each other on both circumferential sides. In the present embodiment, the rotor magnet 54 has a rectangular parallelepiped shape extending in the radial direction. For example, 10 rotor magnets 54 are provided.
The molded resin portion 53 holds the rotor core 52 and the plurality of rotor magnets 54. The molded resin portion 53 is molded by, for example, insert molding in which resin flows into a mold into which the rotor core 52 is inserted. The molded resin portion 53 has a base portion 53a, a plurality of outer side support portions 53b, and a plurality of inner side support portions 53c.
In the present embodiment, the base 53a has an annular shape centered on the central axis J. The base 53a has a plate shape with a plate surface facing in the axial direction. The base 53a is positioned on the left side of the rotor core 52, and supports the rotor core 52 and the plurality of rotor magnets 54 from the left side. In the present embodiment, the base 53a covers the core through portion 55 from the left side. In the present embodiment, the inner diameter of the base portion 53a is substantially the same as the inner diameter of the inner core portion 52 a.
The plurality of outer support portions 53b and the plurality of inner support portions 53c protrude rightward from the base portion 53 a. The plurality of outer support portions 53b are arranged at equal intervals along the circumferential direction. The plurality of inner support portions 53c are arranged at equal intervals along the circumferential direction. The plurality of outer support portions 53b support the plurality of rotor magnets 54 from the radially outer side. The plurality of inner support portions 53c support the plurality of rotor magnets 54 from the radially inner side, respectively.
As shown in fig. 2, in the present embodiment, the stator 60 is located radially outward of the rotor 50. The stator 60 has a stator core 61, an insulator 62, and a plurality of coils 63. The stator core 61 is fixed to the motor case 70. Although not shown, the stator core 61 is formed by stacking electromagnetic steel plates in the axial direction, for example. The stator core 61 has: an annular core back 61a surrounding the rotor 50; and a plurality of teeth 61b extending radially inward from the core back 61 a. Although not shown, the plurality of teeth 61b are arranged at equal intervals along the circumferential direction. The insulators 62 are mounted to the plurality of teeth 61b, respectively. The plurality of coils 63 are mounted on the plurality of teeth 61b via insulators 62.
The motor housing 70 is accommodated inside the hub 30. A gap is provided between the outer side surface of the motor housing 70 and the inner side surface of the hub 30. More specifically, a gap is provided circumferentially between the radially outer side surface of the motor case 70 and the radially inner side surface of the hub 30. An annular gap surrounding the center axis J is provided between the right surface of the motor case 70 and the left surface of the bottom wall portion 33 of the hub 30 in the axial direction.
In the present embodiment, the motor case 70 includes: a 1 st motor bracket 71 located on the right side of the stator 60; and a 2 nd motor bracket 72 located at the left side of the stator 60. The motor case 70 holds the stator 60 in a state of sandwiching the stator 60 in the axial direction by the 1 st motor bracket 71 and the 2 nd motor bracket 72.
The 1 st motor bracket 71 has a bottomed tubular shape opening to the left. The 1 st motor bracket 71 has a 1 st axial wall portion 73, a 1 st peripheral wall portion 74, and a 1 st bearing holding portion 75. The 1 st axial wall portion 73 is an axial wall portion on the right side of the motor case 70. The 1 st axial wall portion 73 is located on the right side of the stator 60. The 1 st axial wall portion 73 covers the stator 60 from the right side. The 1 st axial wall 73 is annular with the central axis J as the center. The 1 st axial wall portion 73 has a plate shape with a plate surface facing in the axial direction. The 1 st axial wall portion 73 has a radially inner edge portion which is a protruding portion 73b protruding rightward. A hub bearing 93 is fixed to the outer peripheral surface of the protruding portion 73b.
The 1 st peripheral wall 74 has a cylindrical shape protruding leftward from the radially outer peripheral edge of the 1 st axial wall 73. In the present embodiment, the 1 st peripheral wall portion 74 has a cylindrical shape that is open to the left with the center axis J as the center. The core back 61a is screwed to the left end of the 1 st peripheral wall 74. The 1 st bearing holding portion 75 is provided at the radially inner edge portion of the 1 st axial wall portion 73. The 1 st bearing holding portion 75 has a cylindrical shape protruding leftward. The 1 st bearing holding portion 75 holds the bearing 91 radially inward.
The 2 nd motor bracket 72 has a bottomed tubular shape opening to the right. The 2 nd motor bracket 72 has a 2 nd axial wall portion 76, a 2 nd peripheral wall portion 77, and a 2 nd bearing holding portion 78. The 2 nd axial wall portion 76 is an axial wall portion of the left side of the motor case 70. The 2 nd axial wall 76 is located on the left side of the stator 60. The 2 nd axial wall portion 76 covers the stator 60 from the left side. The 2 nd axial wall portion 76 has an annular shape centered on the central axis J. The 2 nd axial wall portion 76 has a plate shape with a plate surface facing the axial direction.
The 2 nd peripheral wall portion 77 has a cylindrical shape protruding rightward from the radially outer peripheral edge portion of the 2 nd axial wall portion 76. In the present embodiment, the 2 nd peripheral wall portion 77 has a cylindrical shape that opens to the right with the center axis J as the center. The right end of the 2 nd peripheral wall portion 77 faces the left end of the 1 st peripheral wall portion 74 with a gap therebetween in the axial direction. A part of the outer peripheral surface of the stator core 61 is exposed from the gap in the axial direction between the 1 st peripheral wall portion 74 and the 2 nd peripheral wall portion 77. In the present embodiment, the peripheral wall portion of the motor case 70 is constituted by the 1 st peripheral wall portion 74 and the 2 nd peripheral wall portion 77. The 2 nd bearing holding portion 78 is provided at a radially inner edge portion of the 2 nd axial wall portion 76. The 2 nd bearing holder 78 has a cylindrical shape protruding rightward. The 2 nd bearing holding portion 78 holds the bearing 92 radially inward.
As shown in fig. 4 and 5, the motor housing 70 has a plurality of vent holes 70a connecting the inside of the motor housing 70 with the inside of the hub 30. In the present embodiment, the plurality of vent portions 70a includes: an axial hole portion 70b penetrating through an axial wall portion of the motor case 70 in the axial direction; and a radial hole portion 70c penetrating the peripheral wall portion of the motor case 70 in the radial direction. In the present embodiment, the axial hole 70b includes a 1 st axial hole 73a and a 2 nd axial hole 76a. In the present embodiment, the radial hole 70c includes a 1 st radial hole 74a and a 2 nd radial hole 77a.
As shown in fig. 4, the 1 st axial hole portion 73a is provided in the 1 st axial wall portion 73 of the axial wall portions of the motor case 70. The 1 st axial hole 73a is, for example, substantially rectangular. In the present embodiment, a plurality of 1 st axial hole portions 73a are provided in the circumferential direction. The 1 st axial hole portions 73a are arranged at equal intervals along the circumferential direction. For example, 12 1 st axial hole portions 73a are provided. As shown in fig. 6, the 1 st axial hole 73a is located radially outward of the hub bearing 93. For example, the 1 st axial hole 73a is arranged at a position overlapping with the teeth 61b adjacent in the circumferential direction when viewed in the axial direction.
The 2 nd axial hole portion 76a is provided in the 2 nd axial wall portion 76 of the axial wall portions of the motor case 70. As shown in fig. 5, the 2 nd axial hole portion 76a is, for example, substantially rectangular. In the present embodiment, a plurality of 2 nd axial hole portions 76a are provided in the circumferential direction. The plurality of 2 nd axial hole portions 76a are arranged at equal intervals along the circumferential direction. For example, 12 2 nd axial hole portions 76a are provided. The circumferential positions of the plurality of 2 nd axial hole portions 76a are, for example, the same as the circumferential positions of the plurality of 1 st axial hole portions 73a, respectively. The opening area of each 2 nd axial hole portion 76a is smaller than the opening area of each 1 st axial hole portion 73a.
The 2 nd axial hole portion 76a is provided in a portion near the radially inner side in the 2 nd axial wall portion 76. The portion near the radially inner side in the 2 nd axial wall portion 76 is a portion radially inner than the radial center between the radially inner end of the 2 nd axial wall portion 76 and the radially outer end of the 2 nd axial wall portion 76.
As shown in fig. 6, the 2 nd axial hole 76a is located radially inward of the stator 60. The 2 nd axial hole 76a is located radially inward of the radially outer end of the rotor core 52. In the present embodiment, the radially outer end of the rotor core 52 is the radially outer end of the outer core portion 52 b. The 2 nd axial hole 76a overlaps the outer core portion 52b when viewed in the axial direction. The 2 nd axial hole portion 76a is located radially outward of the bearing 92. The 2 nd axial hole portion 76a is provided in a peripheral edge portion of the 2 nd axial wall portion 76 on the radially outer side of the 2 nd bearing-retaining portion 78.
The 1 st radial hole portion 74a radially penetrates the 1 st peripheral wall portion 74 of the peripheral wall portions of the motor case 70. As shown in fig. 4, the 1 st radial hole 74a has a rectangular shape long in the axial direction, for example, when viewed from the radial outside. In the present embodiment, the 1 st radial hole 74a penetrates the 1 st axial wall 73 in the axial direction at the radially outer peripheral edge thereof. The right end of the 1 st radial hole 74a opens to the right surface of the 1 st axial wall 73. In the present embodiment, a plurality of 1 st radial hole portions 74a are provided along the circumferential direction. The 1 st radial hole portions 74a are arranged at equal intervals along the circumferential direction. For example, 12 1 st radial hole portions 74a are provided. Each 1 st radial hole portion 74a is located radially outward of each 1 st axial hole portion 73a.
The 2 nd radial hole portion 77a penetrates the 2 nd peripheral wall portion 77 in the radial direction. As shown in fig. 5, the 2 nd radial hole portion 77a is rectangular, for example, when viewed from the radial outside. In the present embodiment, the 2 nd radial hole portion 77a axially penetrates the radially outer peripheral edge portion of the 2 nd axial wall portion 76. The left end of the 2 nd radial hole portion 77a opens to the left surface of the 2 nd axial wall portion 76. In the present embodiment, a plurality of 2 nd radial hole portions 77a are provided along the circumferential direction. The 2 nd radial hole portions 77a are arranged at equal intervals along the circumferential direction. For example, 12 2 nd radial hole portions 77a are provided. The circumferential positions of the plurality of 2 nd radial hole portions 77a are, for example, the same as the circumferential positions of the plurality of 1 st radial hole portions 74a, respectively. Each 2 nd radial hole portion 77a is located radially outward of each 2 nd axial hole portion 76a.
As shown in fig. 2, the reduction mechanism 20 includes a sun gear 24, a fixed portion 21, a plurality of planetary gears 22, a plurality of support shafts 23, and an output gear 25. The sun gear 24 is connected to the left end of the motor shaft 51. The sun gear 24 is an external gear coaxial with the motor shaft 51.
The fixing portion 21 is fixed to the left surface of the motor case 70. The fixing portion 21 fixes the plurality of support shafts 23 to the motor 10. The fixing portion 21 has a top wall portion 21a and a plurality of leg portions 21b. The top wall portion 21a covers the motor 10 from the left side. The right end of the hub axle 42 is fixed to the top wall portion 21a. The left end portions of the plurality of support shafts 23 are fixed to the top wall portion 21a. The leg portion 21b extends rightward from the radially outer peripheral edge portion of the top wall portion 21a. The right end of the leg 21b is screwed to the 2 nd axial wall 76 of the 2 nd motor bracket 72. Although not shown, for example, 3 legs 21b are provided along the circumferential direction.
The plurality of planet gears 22 are located radially outward of the sun gear 24. The planetary gear 22 is a secondary gear having 1 set of coaxial external gears different in outer diameter. The planetary gear 22 has a pinion gear 22a on the left side and a bull gear 22b on the right side. The outer diameter of the large gear 22b is larger than the outer diameter of the small gear 22 a. The large gear 22b meshes with the sun gear 24. The planetary gear 22 has a through hole 22c, and the through hole 22c penetrates the centers of the pinion gear 22a and the bull gear 22b in the axial direction.
The plurality of support shafts 23 rotatably support the plurality of planetary gears 22, respectively. The support shaft 23 extends in the axial direction. The support shaft 23 passes through the through hole 22c of the planetary gear 22. The left end of the support shaft 23 is fixed to the top wall portion 21a. The right end of the support shaft 23 is fixed to the 2 nd axial wall portion 76.
The output gear 25 has a circular ring shape surrounding the plurality of planetary gears 22 from the radially outer side. The output gear 25 is an internal gear meshed with the pinion gears 22a of the planetary gears 22. The output gear 25 is fixed to the right side surface of the cover 32. That is, the reduction mechanism 20 is connected to the motor 10 at the sun gear 24 and to the hub 30 at the output gear 25.
The driving device 1 includes at least one fan 80 provided in the rotor 50 inside the motor case 70. In the present embodiment, the fan 80 includes centrifugal fans 81 and 82 capable of blowing air in the radial direction. The centrifugal fans 81 and 82 can supply air in the radial direction by rotating around the central axis J together with the rotor 50. The centrifugal fans 81 and 82 have a ring shape surrounding the central axis J. In the present embodiment, the centrifugal fans 81 and 82 have annular shapes centered on the central axis J. The centrifugal fan 82 has an inner diameter larger than that of the centrifugal fan 81. The centrifugal fan 82 has an outer diameter larger than that of the centrifugal fan 81. The centrifugal fans 81 and 82 are, for example, sirocco fans.
The centrifugal fan 81 is fixed to the motor shaft 51. More specifically, centrifugal fan 81 is fixed to a portion of motor shaft 51 on the right side of the portion to which rotor core 52 is fixed. The centrifugal fan 81 is located on the right side of the inner core portion 52 a. The left surface of the centrifugal fan 81 contacts the right surface of the inner core portion 52 a. In the present embodiment, the centrifugal fan 81 delivers air sucked from the right side to the radially outer side.
As shown in fig. 6, the air AR1 discharged from the centrifugal fan 81 to the radial outside advances radially outward at a portion on the right side of the rotor core 52 and the stator core 61 in the interior of the motor case 70, and is discharged from the 1 st radial hole portion 74a to the exterior of the motor case 70. The air AR1 discharged to the outside of the motor case 70 flows to the 1 st axial hole portion 73a through the gap between the motor case 70 and the hub 30. More specifically, the air AR1 discharged to the outside of the motor case 70 flows rightward along the inner peripheral surface of the tube portion 34, flows radially inward in the axial gap between the 1 st axial wall portion 73 and the bottom wall portion 33, and reaches the 1 st axial hole portion 73a. The air AR1 flows into the motor case 70 again from the 1 st axial hole 73a, and is sucked by the centrifugal fan 81.
The centrifugal fan 82 is fixed to the molded resin portion 53. More specifically, the centrifugal fan 82 is fixed to the left surface of the base 53 a. The centrifugal fan 82 is located on the left side of the outer core portion 52 b. Centrifugal fan 82 is located radially outward of bearing 92. The centrifugal fan 82 is axially opposed to the 2 nd axial hole 76a. In the present embodiment, the centrifugal fan 82 delivers air sucked from the left side to the radially outer side.
The air AR2 discharged from the centrifugal fan 82 to the radial outside advances radially outward at the portion on the left side of the rotor core 52 and the stator core 61 in the interior of the motor case 70, and is discharged from the 2 nd radial hole portion 77a to the exterior of the motor case 70. The air AR2 discharged to the outside of the motor case 70 flows leftward along the inner peripheral surface of the tube 34, and then flows radially inward between the motor 10 and the reduction mechanism 20 in the axial direction. Then, the air AR2 flows into the motor case 70 again from the 2 nd axial hole 76a, and is sucked by the centrifugal fan 82.
According to the present embodiment, the driving device 1 has at least one fan 80 provided to the rotor 50 inside the motor case 70. Accordingly, the fan 80 can be rotated by the rotation of the rotor 50, and the air flow can be generated in the motor case 70 as in the above-described air AR1 and AR 2. Accordingly, the heat generated by the stator 60, more specifically, the heat generated by the coil 63 is easily and suitably transferred to the motor case 70 by the flow of the air generated by the fan 80. Thus, the heat of the stator 60 can be easily discharged from the motor case 70 to the outside of the motor 10. Therefore, the heat dissipation performance of the motor 10 can be improved.
Further, according to the present embodiment, the motor housing 70 has a plurality of vent holes 70a connecting the inside of the motor housing 70 and the inside of the hub 30. Accordingly, by the rotation of the fan 80, the air inside the motor case 70 can be discharged from the vent hole portion 70a to the outside of the motor 10. When the air inside the motor case 70 is discharged to the outside of the motor 10, the pressure inside the motor case 70 is reduced. Accordingly, the air inside the hub 30 is sucked into the motor case 70 from the vent hole 70a different from the vent hole 70a from which the air is discharged. Accordingly, by the rotation of the fan 80 together with the rotor 50, an air flow circulating between the inside and the outside of the motor case 70 as described above is formed as the above-described air AR1 and AR 2. Thus, the heat of the stator 60 can be suitably transferred to the hub 30 accommodating the motor 10 by the air flow generated by the rotation of the fan 80. Accordingly, the heat of the stator 60 can be discharged from the hub 30 to the outside of the drive device 1, and the heat dissipation performance of the motor 10 can be further improved.
Further, according to the present embodiment, the plurality of vent holes 70a includes the axial hole 70b and the radial hole 70c. Therefore, such a cycle is easily generated: air is discharged from one of the axial hole portion 70b and the radial hole portion 70c to the outside of the motor case 70, and air is sucked from the other of the axial hole portion 70b and the radial hole portion 70c to the inside of the motor case 70. As a result, for example, the air flow around the motor housing 70 and the hub 30 can easily flow through both the radial gap between the motor housing 70 and the hub 30 and the axial gap between the motor housing 70 and the hub 30 as in the above-described flow of the air AR 1. Accordingly, the contact area between the air discharged to the outside of the motor case 70 and the inner surface of the hub 30 is easily increased, and the heat of the stator 60 can be more suitably transmitted to the hub 30. Therefore, the heat dissipation performance of the motor 10 can be further improved.
In the present embodiment, the fan 80 includes centrifugal fans 81 and 82. Therefore, as with the above-described air AR1, AR2, the following cycle can be generated: after being discharged to the radial outside from the inside of the motor case 70, the air is sucked from the axial side and returned to the inside of the motor case 70.
Further, in the case where the inside of the hub 30 is sealed as in the present embodiment, the inside of the hub 30 is easily filled with heat, and particularly, the heat of the stator 60 is not easily discharged to the outside. In contrast, according to the present embodiment, the heat radiation performance of the motor 10 can be improved by the flow of air generated by the fan 80 as described above. That is, the above-described effect of improving the heat radiation performance of the motor 10 can be obtained particularly usefully in the case where the inside of the hub 30 is sealed.
Further, as in the present embodiment, when the hub 30 rotates relative to the motor housing 70, a gap is provided between the outer side surface of the motor housing 70 and the inner side surface of the hub 30. In this case, heat is not easily transferred from the motor housing 70 to the hub 30, and heat of the stator 60 is not easily discharged to the outside. In contrast, according to the present embodiment, the heat radiation performance of the motor 10 can be improved by the flow of air generated by the fan 80 as described above. That is, the above-described effect of improving the heat radiation performance of the motor 10 can be obtained particularly usefully in the case where a gap is provided between the outer side surface of the motor case 70 and the inner side surface of the hub 30.
In addition, in many cases, the in-wheel motor of the motor 10 according to the present embodiment is used outdoors, and in particular, tightness of the hub 30 is easily required. Therefore, it is more difficult to discharge the heat of the stator 60 to the outside. In contrast, according to the present embodiment, the heat radiation performance of the motor 10 can be improved by the flow of air generated by the fan 80 as described above. That is, in the case where the motor 10 is an in-wheel motor, the above-described effect of improving the heat radiation performance of the motor 10 can be obtained particularly usefully.
< embodiment 2 >
As shown in fig. 7, in the motor 110 of the driving device 2 of the present embodiment, the 2 nd motor bracket 172 of the motor case 170 does not have the 2 nd radial hole portion 77a. That is, the 2 nd radial hole portion 77a is not provided in the 2 nd peripheral wall portion 177. In the rotor 150 of the present embodiment, the radially inner peripheral edge in the base portion 153a of the molded resin portion 153 is located radially outward of the outer peripheral surface of the inner core portion 52 a. Unlike the base 53a of embodiment 1, the base 153a opens the left end of the core through portion 55.
The fan 180 of the present embodiment includes an axial fan 181 capable of blowing air in the axial direction. The axial fan 181 is fixed to a portion of the motor shaft 51 on the right side of the portion to which the rotor core 52 is fixed. The axial fan 181 has: a circular tube portion 181a, wherein the tube portion 181a is fitted and fixed to the motor shaft 51; and a plurality of blade portions 181b, the plurality of blade portions 181b being provided on the outer peripheral surface of the tube portion 181 a. The blade portion 181b is disposed opposite to the right side of the core penetration portion 55.
In the present embodiment, the axial fan 181 rotates together with the rotor 150 to supply air to the left side. The axial fan 181 blows air from the right side of the rotor core 52 to the left side of the rotor core 52 through the core penetration portion 55. Therefore, the flow of air is easily formed inside the motor case 170 by the axial flow fan 181.
Specifically, in the present embodiment, the air AR3 discharged to the left from the axial fan 181 is discharged to the left of the motor case 170 through the core through-portion 55 and the 2 nd axial hole portion 76a. The air AR3 discharged to the left of the motor case 170 flows radially outward between the motor 110 and the axial direction of the reduction mechanism 20. Then, the air AR3 advances rightward along the inner peripheral surface of the tubular portion 34, and flows into the motor case 170 again from the 1 st radial hole portion 74a and the 1 st axial hole portion 73a, respectively.
As shown in fig. 8, the core through portion 55 is connected to the inside of the hole 52d of the connecting portion 52c. Therefore, the air AR3 passing through the core through portion 55 easily enters the inside of the hole portion 52d, and becomes turbulent. Turbulence has a higher thermal conductivity than laminar flow. This makes it possible to more easily transfer heat of the stator 60 to the hub 30 by the air AR3 passing through the core through-portion 55. Thus, the heat dissipation of the motor 110 can be further improved.
In the present embodiment, the fan 180 includes a suction fan 182 capable of introducing air to the radially inner side. The suction fan 182 is fixed to the molded resin portion 153. In more detail, the suction fan 182 is fixed to the left side surface of the base 153 a. The suction fan 182 is located on the left side of the rotor core 52. In the present embodiment, the suction fan 182 is constituted by a plurality of blade portions 182 a. The plurality of blade portions 182a are arranged at equal intervals along the circumferential direction. The vane portion 182a extends obliquely to the radial direction and the circumferential direction. In the present embodiment, the blade 182a is integrally molded with the molded resin portion 153, for example.
As shown in fig. 7, when the suction fan 182 rotates in the same direction as the direction in which the axial flow fan 181 rotates in the left air blowing direction, air is introduced into the radial direction. Since the suction fan 182 is located at the left side of the rotor core 52, air at a portion of the inside of the motor case 170 located at the left side of the stator 60 is introduced to the radially inner side. The air AR4 introduced to the radially inner side by the suction fan 182 is discharged to the outside of the motor case 170 from the 2 nd axial hole portion 76a together with the air AR3 blown by the axial flow fan 181.
Here, the air AR3 discharged from the axial fan 181 to the left tends to spread radially outward as it advances to the left. Therefore, as in the present embodiment, when the 2 nd axial hole 76a is provided in a portion near the radially inner side of the 2 nd axial wall 76, there is a possibility that the air AR3 flowing leftward from the rotor core 52 through the core penetration portion 55 may spread radially outward from the 2 nd axial hole 76a. In this case, the air AR3 is less likely to be discharged from the 2 nd axial hole 76a, and the heat dissipation performance of the motor 110 may be reduced.
In contrast, according to the present embodiment, the suction fan 182 capable of introducing air to the radially inner side is provided. Therefore, the air AR3 flowing to the left side of the rotor core 52 via the core penetration portion 55 is easily guided to the radial inside by the air AR4 introduced by the suction fan 182. Thereby, the air AR3 is easily discharged to the outside of the motor case 170 from the 2 nd axial hole portion 76a together with the air AR4 introduced by the suction fan 182. Thus, the heat dissipation of the motor 110 can be suppressed from decreasing.
Here, as in the present embodiment, when the reduction mechanism 20 is fixed to the left surface of the motor case 170, the area where the 2 nd axial hole 76a can be provided in the 2 nd axial wall 76 is limited. Therefore, the 2 nd axial hole portion 76a is easily provided in a portion near the radially inner side in the 2 nd axial wall portion 76. Therefore, the above-described effect by providing the suction fan 182 can be obtained particularly usefully in the case where the reduction mechanism 20 is fixed to the left side surface of the motor case 170.
The present invention is not limited to the above-described embodiment, and the following configuration can be adopted. The 1 st casing, that is, the motor casing in the above embodiment, is not particularly limited as long as the rotor and the stator can be accommodated therein. Only the axial hole portion or the radial hole portion of the vent hole portion may be provided in the 1 st housing. The 1 st housing may not be provided with a vent hole.
The fan is not particularly limited as long as at least one fan is provided on the rotor inside the 1 st casing. The fan may include a fan of a type other than the above-described embodiment. The number of fans may be 1 or 3 or more. The fan may also be indirectly arranged to the rotor. For example, in the case where the speed reducing mechanism is disposed in the 1 st housing, the fan may be disposed on the rotor via the speed reducing mechanism. In addition, as in the above-described embodiment, by providing the fan on the rotor before deceleration, the rotation speed of the fan can be increased, and therefore, the heat radiation performance of the motor can be more suitably improved.
The 2 nd housing, that is, the hub in the above embodiment, is not particularly limited as long as the motor is accommodated inside. The 2 nd casing may not rotate. The interior of the 2 nd casing may not be closed.
The motor of the above embodiment is an in-wheel motor that rotates the wheels of the vehicle, but is not limited thereto. The use of the motor is not particularly limited. In addition, the respective structures described in the present specification can be appropriately combined within a range not contradicting each other.

Claims (8)

1. A driving device, comprising:
a motor including a rotor rotatable about a central axis, a stator facing the rotor radially outward with a gap therebetween, and a 1 st housing accommodating the rotor and the stator therein;
a 2 nd casing, wherein the 2 nd casing accommodates the motor and the speed reducing mechanism inside; and
at least one fan arranged in the rotor inside the 1 st housing,
the stator has a stator core and a plurality of coils,
the 1 st housing has a plurality of vent hole portions connecting the inside of the 1 st housing with the inside of the 2 nd housing, the plurality of vent hole portions including radial hole portions penetrating the peripheral wall portion of the 1 st housing in the radial direction,
the inside of the 2 nd casing is sealed,
the axial position of the fan is located outside the end surface of the stator core.
2. The driving device according to claim 1, wherein,
the plurality of vent hole portions include an axial hole portion that axially penetrates through an axial wall portion of the 1 st housing.
3. The driving device according to claim 2, wherein,
the fan comprises a centrifugal fan capable of supplying air in a radial direction.
4. A driving device according to claim 2 or 3, wherein,
the fan includes an axial flow fan capable of supplying air in an axial direction.
5. The driving device according to claim 4, wherein,
the rotor has a rotor core that is provided with a plurality of rotor cores,
the rotor core has a core penetration portion penetrating the rotor core in an axial direction,
the axial hole portion includes:
a 1 st axial hole portion provided in an axial wall portion on one axial side of the 1 st casing; and
a 2 nd axial hole part, the 2 nd axial hole part is arranged on the axial wall part on the other axial side of the 1 st shell,
the axial flow fan supplies air from a position on one side of the rotor core in the axial direction to a position on the other side of the rotor core in the axial direction through the core penetrating portion.
6. The driving device according to claim 5, wherein,
the 2 nd axial hole portion is provided at a portion near the radially inner side in the axial wall portion on the other axial side of the 1 st housing,
the fan comprises a suction fan capable of sucking air to a radially inner side,
the suction fan is located at the other axial side of the rotor core.
7. A driving device according to any one of claims 1 to 3, wherein,
the 1 st housing holds the stator,
the 2 nd casing can rotate around the central axis,
a gap is arranged between the outer side surface of the 1 st shell and the inner side surface of the 2 nd shell.
8. A driving device according to any one of claims 1 to 3, wherein,
the motor is an in-wheel motor that rotates a wheel of the vehicle.
CN202010102075.6A 2019-03-28 2020-02-19 Driving device Active CN111756175B (en)

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