WO2021090577A1 - Actionneur électrique - Google Patents

Actionneur électrique Download PDF

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Publication number
WO2021090577A1
WO2021090577A1 PCT/JP2020/034822 JP2020034822W WO2021090577A1 WO 2021090577 A1 WO2021090577 A1 WO 2021090577A1 JP 2020034822 W JP2020034822 W JP 2020034822W WO 2021090577 A1 WO2021090577 A1 WO 2021090577A1
Authority
WO
WIPO (PCT)
Prior art keywords
brushless motor
electric actuator
bracket
housing
stator
Prior art date
Application number
PCT/JP2020/034822
Other languages
English (en)
Japanese (ja)
Inventor
剛 戸塚
龍之 齋藤
渡邉　哲也
陽平 増田
Original Assignee
株式会社ミツバ
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社ミツバ filed Critical 株式会社ミツバ
Publication of WO2021090577A1 publication Critical patent/WO2021090577A1/fr

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/20—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for measuring, monitoring, testing, protecting or switching
    • H02K11/21—Devices for sensing speed or position, or actuated thereby
    • H02K11/215—Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/30—Structural association with control circuits or drive circuits
    • 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
    • H02K5/18—Casings or enclosures characterised by the shape, form or construction thereof with ribs or fins for improving heat transfer
    • 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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K9/00—Arrangements for cooling or ventilating
    • H02K9/22—Arrangements for cooling or ventilating by solid heat conducting material embedded in, or arranged in contact with, the stator or rotor, e.g. heat bridges

Definitions

  • the present invention relates to an electric actuator, and particularly to an electric actuator powered by a brushless motor.
  • an electric actuator is built in the wheels of a walking assist vehicle or a wheelchair as a drive source for the walking assist vehicle or the wheelchair.
  • the electric actuator used for this type of application is required to have a shape suitable for being incorporated in a wheel as well as being small and lightweight.
  • a thin electric actuator whose axial dimension is smaller than the radial dimension has been developed and put into practical use.
  • the brushless motor that is the power source of such a thin electric actuator needs to have a flat shape in which the axial dimension is smaller than the radial dimension.
  • a flat brushless motor having an axial dimension smaller than the radial dimension is sometimes called a "flat motor” to distinguish it from a motor having an axial dimension larger than the radial dimension.
  • a brushless motor whose axial dimension is larger than its radial dimension is sometimes called a "cylindrical motor”. Therefore, also in the present specification, a brushless motor having an axial dimension smaller than the radial dimension is referred to as a "flat motor”, and a brushless motor having an axial dimension larger than the radial dimension is referred to as a "cylindrical motor”. May be done.
  • brushless motors whether flat motors or tubular motors, include an annular stator and a rotor located inside or outside the stator and generate heat during operation. ..
  • the main heat source in the brushless motor is the stator, and a part of the heat generated from the stator is directly transferred to the housing containing the brushless motor including the stator. Further, the other part of the heat generated from the stator is indirectly transferred to the housing through various members arranged between the stator and the housing. The heat transferred to the housing in this way diffuses throughout the housing and is released into the air from the surface of the housing.
  • a conventional electric actuator powered by an inner rotor type brushless motor in which the rotor is arranged inside the stator most of the heat generated from the stator surrounds the outer peripheral surface from the outer peripheral surface of the stator. It is transmitted to the peripheral wall of the electric actuator housing. That is, in the conventional electric actuator powered by the inner rotor type brushless motor, the outer peripheral surface of the stator and the peripheral wall of the housing of the electric actuator form the main part of the heat path for transmitting the heat generated from the brushless motor. ..
  • the heat generated from the brushless motor which is the power source of the electric actuator, is transmitted to the housing of the electric actuator and released into the air through the housing. That is, in the conventional electric actuator, the heat generated from the brushless motor (mainly the stator) is dissipated through the housing to cool the brushless motor.
  • the power source of the electric actuator is a flat motor
  • the area of the outer peripheral surface of the stator and the peripheral wall of the housing surrounding the stator is usually smaller than that when the power source of the electric actuator is a tubular motor. is there.
  • the outer peripheral surface of the stator and the peripheral wall of the housing form the main part of the heat path.
  • An object of the present invention is to realize an electric actuator having excellent cooling performance for a brushless motor which is a power source.
  • the electric actuator of the present invention includes a brushless motor including a stator and a rotor, a housing for accommodating the brushless motor, a flat housing having an axial dimension smaller than a radial dimension, and the brushless motor accommodated in the housing. It has a control board and a speed reduction mechanism that reduces the rotation speed of the power output from the brushless motor and outputs the speed reduction mechanism, which is integrated with the housing.
  • the housing includes a cover and a bracket that face each other in the axial direction with the brushless motor in between. Then, between the brushless motor and the bracket, a sheet-shaped heat conductive member having a first surface in close contact with the stator and a second surface opposite to the first surface in close contact with the bracket is arranged. There is.
  • the first surface of the heat conductive member is in close contact with the coil provided on the stator.
  • control board is arranged between the brushless motor and the cover, and a Hall element is provided on one surface of the control board facing the brushless motor.
  • the cover is made of resin or metal
  • the bracket is made of metal
  • an electric actuator having excellent cooling performance for a brushless motor as a power source is realized.
  • FIG. 1 It is a perspective view of the electric actuator to which this invention is applied. It is sectional drawing which shows the structure of the electric actuator shown in FIG. It is an exploded perspective view which shows the structure of the electric actuator shown in FIG.
  • the electric actuator according to the present embodiment is built in the wheels of the walking assistance vehicle as a drive source of the electric walking assistance vehicle.
  • the electric actuator according to the present embodiment is an in-wheel motor mounted on the walking assist vehicle as a drive source of the electric walking assist vehicle.
  • the application of the electric actuator to which the present invention is applied is not limited to the drive source of the electric walking assist vehicle.
  • the electric actuator 1A includes a resin or metal cover 10 and a metal bracket 20.
  • the cover 10 and the bracket 20 are fixed so as to be abutted against each other to form the housing 30.
  • the housing 30 has an axial dimension (L) smaller than the radial dimension (D) and exhibits a flat disk-shaped outer shape as a whole.
  • the cover 10 in this embodiment is made of synthetic resin
  • the bracket 20 is made of aluminum. Further, the cover 10 and the bracket 20 in this embodiment are fixed to each other by a plurality of screws SC.
  • the cover 10 has a disk-shaped bottom wall 11 and a tubular side wall 12 rising from the peripheral edge of the bottom wall 11.
  • the side wall 12 of the cover 10 is provided with a first cable fixing portion 13 and a second cable fixing portion 14.
  • the cable 15 with the first connector is fixed to the first cable fixing portion 13, and the cable 16 with the second connector is fixed to the second cable fixing portion 14.
  • One end side of the cable 15 with the first connector is drawn into the cover 10 (housing 30) through the first cable fixing portion 13, and the connector 15a is provided on the other end side of the cable 15 with the first connector. There is.
  • one end side of the cable 16 with the second connector is drawn into the cover 10 (housing 30) through the second cable fixing portion 14, and the connector 16a is located on the other end side of the cable 16 with the second connector. It is provided.
  • the connectors 15a and 16a are connected to external connectors that are electrically connected to the battery, operation switch, controller, and the like.
  • the bracket 20 has a flange portion 21 fixed to the cover 10, a first annular wall 22 having a diameter smaller than that of the flange portion 21, and a second annular wall having a diameter smaller than that of the first annular wall 22. It includes a wall 23, a third annular wall 24 having a diameter smaller than that of the second annular wall 23, and a fourth annular wall 25 having a diameter smaller than that of the third annular wall 24, and has a stepped tubular shape as a whole.
  • the brushless motor 40 which is the power source of the electric actuator 1A, is housed in a housing 30 composed of a cover 10 and a bracket 20 which are abutted against each other.
  • the cover 10 and the bracket 20 constituting the housing 30 face each other in the axial direction with the brushless motor 40 interposed therebetween.
  • the brushless motor 40 housed in the housing 30 is a flat motor whose axial dimension is smaller than its radial dimension.
  • the axial direction of the brushless motor 40 is the same as the axial direction of the housing 30, and coincides with the vertical direction of the paper surface in FIG.
  • the radial direction of the brushless motor 40 is the same as the radial direction of the housing 30, and coincides with the left-right direction of the paper surface in FIG.
  • the brushless motor 40 and the control board 50 that controls the operation of the brushless motor 40 are housed.
  • the cover 10, the control board 50, the brushless motor 40, and the bracket 20 overlap in this order in the axial direction.
  • the control board 50 and the brushless motor 40 are arranged between the cover 10 and the bracket 20.
  • the control board 50 is arranged between the cover 10 and the brushless motor 40
  • the brushless motor 40 is arranged between the control board 50 and the bracket 20.
  • the side where the cover 10 and the control board 50 are located is defined as the lower side in the axial direction (downward in the axial direction), and the side where the bracket 20 is located is the axis. It is defined as the upper direction (upper axis direction). That is, the upper part of the paper surface in FIG. 2 is the upper part in the axial direction, and the lower part of the paper surface in FIG.
  • the brushless motor 40 is an inner rotor type brushless motor including a stator 41 and a rotor 42 arranged inside the stator 41.
  • the stator 41 includes an annular stator core 43 made of a plurality of laminated steel plates, and a rotor 42 is arranged inside the stator core 43.
  • the stator core 43 is fixed to the bracket 20, while the rotor 42 is rotatably supported by the bracket 20.
  • a predetermined air gap is provided between the rotor 42 and the stator core 43.
  • the stator core 43 is equipped with an insulator 44 formed of an insulating material.
  • the insulator 44 is formed of, for example, a synthetic resin such as a PBT resin (polybutylene terephthalate).
  • a conducting wire is wound around a predetermined portion of the insulator 44 that covers the teeth of the stator core 43. That is, a plurality of coils 45 are provided on the stator core 43, and an insulator 44 is interposed between each coil 45 and the stator core 43.
  • a plurality of permanent magnets 46 are provided on the outer peripheral surface of the rotor 42.
  • the permanent magnets 46 are arranged along the circumferential direction of the rotor 42 so that the north and south poles alternately appear on the side of the stator core 43 facing the inner peripheral surface.
  • the permanent magnet 46 can also be replaced with an annular permanent magnet in which a portion magnetized on the north pole and a portion magnetized on the south pole are alternately arranged.
  • a rotor shaft 47 is provided in the center of the rotor 42.
  • the rotor shaft 47 is fixed to the rotor 42 and rotates integrally with the rotor 42.
  • the rotor shaft 47 includes a first shaft portion fixed to the center of the rotor 42, a second shaft portion eccentric with respect to the first shaft portion, and a third shaft portion concentric with the first shaft portion. There is.
  • the first shaft portion, the second shaft portion, and the third shaft portion are arranged in this order from the lower side to the upper side in the axial direction.
  • the first shaft portion fixed to the rotor 42 is rotatably supported by the bracket 20 via a bearing. Therefore, when the rotor 42 rotates, the rotor shaft 47 rotates with respect to the bracket 20.
  • the electric actuator 1A has a built-in reduction mechanism 60.
  • the speed reduction mechanism 60 is fitted into a recess provided in the center of the bracket 20 and fixed to the bracket 20. That is, the reduction mechanism 60 is integrated with the housing 30.
  • the reduction gear mechanism 60 is a hypocycloid reduction mechanism composed of an outer gear 61, an inner gear 62, an output rotating body 63, and the like, and determines the rotation speed of the power output from the brushless motor 40. Reduce and output.
  • the reduction ratio of the reduction mechanism 60 in the present embodiment is any ratio in the range of 10: 1 to 40: 1.
  • the output rotating body 63 of the speed reduction mechanism 60 is connected to the wheels of the electric walking assist vehicle.
  • three Hall elements 51 are provided on one surface of the control board 50 facing the brushless motor 40.
  • the Hall element 51 is mounted at a position facing the permanent magnet 46 provided on the rotor 42.
  • Each Hall element 51 outputs a signal corresponding to a change in the magnetic field accompanying the rotation of the rotor 42 (permanent magnet 46).
  • the cable 15 with the first connector and the cable 16 with the second connector are connected to the other surface of the control board 50 (the surface opposite to the surface on which the Hall element 51 is mounted). (Fig. 2 shows only the cable 15 with the first connector).
  • the signal output from the Hall element 51 is input to the cable 15 with the first connector and the cable 16 with the second connector via the wiring provided on the control board 50, and the cable 15 with the first connector and the cable with the second connector are attached. It is sent to a controller (not shown) or the like via a cable 16.
  • a sheet-shaped heat conductive member 70 is arranged between the brushless motor 40 and the bracket 20.
  • the heat conductive member 70 is arranged in the gap between the brushless motor 40 and the bracket 20.
  • the heat conductive member 70 may be referred to as a "heat conductive sheet 70".
  • the heat conductive sheet 70 has an annular planar shape substantially the same as the planar shape of the stator 41. As shown in FIG. 2, the first surface 71 of the heat conductive sheet 70 is in close contact with the stator 41, and the second surface 72 on the opposite side of the first surface 71 is in close contact with the bracket 20. More specifically, the first surface 71 of the heat conductive sheet 70 is in close contact with the coil 45 provided on the stator 41.
  • the stator 41 and the bracket 20 are thermally connected via the heat conductive sheet 70.
  • the coil 45 and the bracket 20, which generate the most heat during the operation of the brushless motor 40 are directly thermally connected via the heat conductive sheet 70. Therefore, the heat generated from the brushless motor 40 is efficiently transferred to the metal bracket 20 and released into the air from the surface of the bracket 20. That is, the electric actuator 1A according to the present embodiment is excellent in cooling performance of the brushless motor 40 which is a power source.
  • the bracket 20 for transmitting the heat generated from the brushless motor 40 via the heat conductive sheet 70 is arranged above the brushless motor 40 in the axial direction.
  • the control board 50 is arranged below the brushless motor 40 in the axial direction. In other words, the bracket 20 and the control board 50 are separately arranged above and below the brushless motor 40. Then, most of the heat generated from the brushless motor 40 is transferred to the bracket 20 located above the brushless motor 40 via the heat conductive sheet 70. As a result, the temperature rise of the control board 50 on which the heat-sensitive Hall element 51 is mounted is suppressed.
  • the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist thereof.
  • the deceleration mechanism built into the electric actuator is not limited to the hypocycloid deceleration mechanism, and may be another type of deceleration mechanism.
  • the reduction ratio of the reduction mechanism can be changed as appropriate.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Motor Or Generator Frames (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
  • Motor Or Generator Cooling System (AREA)

Abstract

La présente invention permet d'obtenir un actionneur électrique présentant une performance de refroidissement supérieure pour un moteur sans balai qui est une source d'énergie. L'actionneur électrique (1A) comprend : un moteur sans balai (40) comprenant un stator (41) et un rotor (42) ; un boîtier plat (30) recevant le moteur sans balai (40) et ayant une dimension axiale plus petite qu'une dimension radiale de celui-ci ; une carte de commande (50) logée dans le boîtier (30) conjointement avec le moteur sans balai (40) ; et un mécanisme de réduction de vitesse (60) qui est intégré au boîtier (30), qui réduit la vitesse de rotation de la puissance de sortie du moteur sans balai (40), et qui délivre en sortie la vitesse de rotation réduite. Le boîtier (30) comprend un couvercle (10) et un support (20) qui sont orientés axialement l'un vers l'autre, le moteur sans balai (40) se trouvant entre eux. Une feuille thermoconductrice (70) ayant une première surface (71) collée au stator (41) et une seconde surface (72) collée au support (20) est disposée entre le moteur sans balai (40) et le support (20).
PCT/JP2020/034822 2019-11-06 2020-09-15 Actionneur électrique WO2021090577A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2019-201354 2019-11-06
JP2019201354A JP2021078194A (ja) 2019-11-06 2019-11-06 電動アクチュエータ

Publications (1)

Publication Number Publication Date
WO2021090577A1 true WO2021090577A1 (fr) 2021-05-14

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ID=75849871

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Application Number Title Priority Date Filing Date
PCT/JP2020/034822 WO2021090577A1 (fr) 2019-11-06 2020-09-15 Actionneur électrique

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JP (1) JP2021078194A (fr)
WO (1) WO2021090577A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006282158A (ja) * 2005-03-08 2006-10-19 Honda Motor Co Ltd 車両用ホイール駆動装置
JP2017073860A (ja) * 2015-10-06 2017-04-13 株式会社ミツバ 電動機
JP2019075974A (ja) * 2017-10-16 2019-05-16 株式会社ミツバ 駆動装置

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6608304B2 (ja) * 2016-02-17 2019-11-20 株式会社ミツバ モータおよび減速機付モータ

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006282158A (ja) * 2005-03-08 2006-10-19 Honda Motor Co Ltd 車両用ホイール駆動装置
JP2017073860A (ja) * 2015-10-06 2017-04-13 株式会社ミツバ 電動機
JP2019075974A (ja) * 2017-10-16 2019-05-16 株式会社ミツバ 駆動装置

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JP2021078194A (ja) 2021-05-20

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