WO2021246473A1 - Motor unit and electric automobile - Google Patents

Motor unit and electric automobile Download PDF

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Publication number
WO2021246473A1
WO2021246473A1 PCT/JP2021/021133 JP2021021133W WO2021246473A1 WO 2021246473 A1 WO2021246473 A1 WO 2021246473A1 JP 2021021133 W JP2021021133 W JP 2021021133W WO 2021246473 A1 WO2021246473 A1 WO 2021246473A1
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WO
WIPO (PCT)
Prior art keywords
motor unit
shaft
drive gear
motor
stage
Prior art date
Application number
PCT/JP2021/021133
Other languages
French (fr)
Japanese (ja)
Inventor
将史 川上
Original Assignee
パナソニックＩｐマネジメント株式会社
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 パナソニックＩｐマネジメント株式会社 filed Critical パナソニックＩｐマネジメント株式会社
Priority to DE212021000391.5U priority Critical patent/DE212021000391U1/en
Publication of WO2021246473A1 publication Critical patent/WO2021246473A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M6/00—Rider propulsion of wheeled vehicles with additional source of power, e.g. combustion engine or electric motor
    • B62M6/40—Rider propelled cycles with auxiliary electric motor
    • B62M6/55—Rider propelled cycles with auxiliary electric motor power-driven at crank shafts parts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M11/00—Transmissions characterised by the use of interengaging toothed wheels or frictionally-engaging wheels
    • B62M11/02—Transmissions characterised by the use of interengaging toothed wheels or frictionally-engaging wheels of unchangeable ratio
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M6/00—Rider propulsion of wheeled vehicles with additional source of power, e.g. combustion engine or electric motor
    • B62M6/40—Rider propelled cycles with auxiliary electric motor
    • B62M6/45—Control or actuating devices therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/02—Toothed members; Worms
    • F16H55/06—Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H1/00—Toothed gearings for conveying rotary motion
    • F16H1/02—Toothed gearings for conveying rotary motion without gears having orbital motion
    • F16H1/04—Toothed gearings for conveying rotary motion without gears having orbital motion involving only two intermeshing members
    • F16H1/06—Toothed gearings for conveying rotary motion without gears having orbital motion involving only two intermeshing members with parallel axes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H1/00—Toothed gearings for conveying rotary motion
    • F16H1/02—Toothed gearings for conveying rotary motion without gears having orbital motion
    • F16H1/04—Toothed gearings for conveying rotary motion without gears having orbital motion involving only two intermeshing members
    • F16H1/06—Toothed gearings for conveying rotary motion without gears having orbital motion involving only two intermeshing members with parallel axes
    • F16H1/08—Toothed gearings for conveying rotary motion without gears having orbital motion involving only two intermeshing members with parallel axes the members having helical, herringbone, or like teeth

Definitions

  • the electric bicycle according to one aspect of the present disclosure includes the motor unit according to the one aspect and wheels to which the rotational force of the motor of the motor unit is transmitted.
  • the frame 10 has a head pipe 101, an upper pipe 102, a lower pipe 103, a vertical pipe 104, a seat stay 105, a chain stay 106, and a bracket 107.
  • the frame 10 (that is, each of the above parts constituting the frame 10) is made of a metal such as aluminum or stainless steel, but may contain a non-metal as a part.
  • the entire frame 10 may be made of non-metal, and the material of the frame 10 is not particularly limited.
  • a handle post 12 is rotatably inserted through the head pipe 101.
  • a front fork 121 is formed at the lower end of the handle post 12.
  • a front wheel 111 is rotatably attached to the front fork 121.
  • a handlebar 122 is fixed to the upper end of the handlepost 12.
  • the unit case 9 houses a crank shaft 6, an input body 7, an output body 8, a deceleration mechanism 4, and the like. Has been done.
  • the intermediate member 93 is a separate member from the first divided body 91 and the second divided body 92, but the intermediate member 93 may be integrally formed with the first divided body 91 or the second divided body 92.
  • the heat radiating portion 925 and the heat conductive member 95 are within the range of the outer shape of the stator 53 described later.
  • the entire heat conductive member 95 may be within the range of the outer shape of the stator 53, or a part of the heat conductive member 95 may be within the range of the outer shape of the stator 53.
  • the motor 5 has a cylindrical motor shaft 51, a rotor 52 coupled to the motor shaft 51 so as to rotate integrally with the motor shaft 51, and a cylindrical stator 53 located so as to surround the rotor 52.
  • a recess 912 for arranging the bearing 551 is formed on the inner surface of the first split body 91.
  • the bearing 551 is a bearing that rotatably supports the first end portion 511 of the motor shaft 51 in the axial direction.
  • the intermediate member 93 is formed with a through hole 931 through which the motor shaft 51 is inserted and a recess 932 for arranging the bearing 552.
  • the recess 932 is formed on the inner peripheral surface of the through hole 931.
  • the bearing 552 rotatably supports the axially intermediate portion 515 of the motor shaft 51.
  • the bearing 551 is referred to as the first bearing 551
  • the bearing 552 is referred to as the second bearing 552.
  • Both the first bearing 551 and the second bearing 552 are ring-shaped deep groove ball bearings.
  • the inner diameter of the second bearing 552 is set to be larger than the inner diameter of the first bearing 551.
  • the inner diameter of the first bearing 551 is preferably set within the range of 7 mm to 8 mm, for example, 7 mm or 8 mm.
  • the inner diameter of the second bearing 552 is preferably set within the range of 10 mm to 12 mm, for example, 10 mm, 11 mm or 12 mm.
  • the inner diameter of the second bearing 552 is preferably smaller than the outer diameter of the first bearing 551.
  • the second bearing 552 of the first bearing 551 and the second bearing 552 on the side closer to the drive gear 413 (and the driven gear 415 described later) has a relatively large inner diameter larger than that of the first bearing 551.
  • the bearing has the advantage that the rigidity of the entire configuration that supports the motor shaft 51 is increased, and as a result, the accuracy of meshing between the first-stage drive gear 413 and the driven gear 415 is improved.
  • the input body 7 is arranged in the unit case 9 along the outer peripheral surface of the crank shaft 6.
  • the input body 7 is a cylindrical member and rotates integrally with the crank shaft 6.
  • the input body 7 is divided into a first input body 71 and a second input body 72.
  • the second input body 72 is connected to the crank shaft 6 in the second split body 92.
  • the first input body 71 is connected to the output body 8 via a one-way clutch in the first split body 91, and is configured to transmit a rotational force to the output body 8.
  • the first input body 71 and the second input body 72 are separately configured, but the first input body 71 and the second input body 72 are integrally configured. May be good.
  • the number of deceleration stages of the deceleration mechanism 4 in the present application is defined.
  • the number of deceleration stages of the deceleration mechanism 4 is the number of portions (that is, deceleration portions) in the power transmission path from the motor shaft 51 to the output body 8 where the rotation speed is reduced.
  • the speed reducer includes a plurality of rotating bodies connected to each other so as to be able to transmit power. In the speed reduction mechanism 4, when the rotation is transmitted through these plurality of rotating bodies, the rotation speed is reduced.
  • the rotating body is, for example, a gear, a sprocket, or the like.
  • the plurality of rotating bodies may come into contact with each other to transmit rotation, or may transmit rotation via a power transmission body such as a chain or a belt.
  • the deceleration mechanism 4 included in the motor unit 3 of one embodiment has three deceleration units (that is, first-stage, second-stage, and third-stage deceleration units 41, 42, 43). It is a deceleration mechanism with three-stage deceleration.
  • the first-stage drive gear 413 is composed of tooth portions formed by plastic working a part of a metal motor shaft 51.
  • the first-stage drive gear 413 is a part of the motor shaft 51 and is made of metal.
  • the motor shaft 51 has a first end portion 511 supported by the first bearing 551, an intermediate portion 515 supported by the second bearing 552, and a portion 513 farther from the first end portion 511 than the intermediate portion 515.
  • a first-stage drive gear 413 is formed on the outer peripheral surface of this portion 513 by plastic working.
  • the first-stage drive gear 413 is provided with shot peening, air blasting or coating.
  • Polyacetal is classified into two types, homopolymer and copolymer, based on its molecular structure. It is possible to use either homopolymer or copolymer type polyacetal as the material for the driven gear 415.
  • a first reduction shaft 45 made of metal is fixed to the inner peripheral surface of the driven gear 415 of the first stage.
  • the first end portion 451 of the first reduction shaft 45 is rotatably supported by a bearing 461 arranged on the intermediate member 93.
  • the second end portion 452 of the first reduction shaft 45 is rotatably supported by a bearing 462 arranged in the second split body 92.
  • the first end portion 451 and the second end portion 452 of the first reduction shaft 45 are located on opposite sides of each other.
  • Both the bearing 461 and the bearing 462 are ring-shaped deep groove ball bearings.
  • the inner diameters of the bearings 461 and 462 are the same, and the outer diameters of the bearings 461 and 462 are the same.
  • At least a part of the bearing 461 is located at a position overlapping with the control board 35.
  • the first reduction shaft 45 made of metal functions as a core metal inserted into the driven gear 415 made of resin. As a result, the strength of the driven gear 415 made of resin is further increased. Further, the material of the driven gear 415 is polyacetal having a property of lower heat resistance than, for example, nylon, but the heat dissipation of the driven gear 415 is enhanced via the first reduction shaft 45 made of metal. ..
  • the first reduction shaft 45 and the driven gear 415 may be provided by integral molding such as insert molding, or the first reduction shaft 45 may be provided by press-fitting the first reduction shaft 45 into the through hole of the driven gear 415.
  • the drive gear 413 and the driven gear 415 described above constitute the first-stage reduction gear 41.
  • the structures of the first-stage drive gear 413 and the driven gear 415 will be described in more detail.
  • the module of the first stage drive gear 413 is set to 0.8 mm or more.
  • the module is calculated by dividing the reference circle diameter of the gear by the number of teeth. The larger the module, the larger the size of each tooth is set under the condition that the reference circle diameter of the drive gear 413 is the same. Therefore, the teeth of the drive gear 413 and the driven gear 415 are less likely to break, and the strength is increased.
  • the number of teeth of the first stage drive gear 413 is 6 or less and 2 or more. That is, the number of teeth of the first stage drive gear 413 may be 6, 5, 4, 3 or 2. It is also preferable that the number of teeth of the drive gear 413 is set to 5 or less, or 4 or less. The smaller the number of teeth, the larger the size of each tooth is set under the condition that the reference circle diameter of the drive gear 413 is the same. Therefore, the teeth of the drive gear 413 and the driven gear 415 are less likely to break, and the strength is increased.
  • the reduction ratio of the first-stage reduction unit 41 is set, for example, in the range of 6 to 7.
  • the reduction ratio of the deceleration unit 41 of the first stage is preferably set to 10 or less, further set to 9 or less, set to 8 or less, set to 7 or less, or It is also preferable to set it to 6 or less.
  • the smaller the reduction ratio of the first-stage reduction gear 41 the smaller the load per tooth of the drive gear 413 and the driven gear 415. Therefore, the teeth of the drive gear 413 and the driven gear 415 are less likely to break, and the strength is increased.
  • the second-stage driven gear 425 is a member that rotates by receiving the rotational driving force of the first reduction shaft 45 by meshing with the second-stage drive gear 423.
  • a plurality of teeth that mesh with the second-stage drive gear 423 are formed on the outer peripheral surface of the second-stage driven gear 425.
  • the control board 35 is located between the stator 53 of the motor 5 and the driven gear 415 of the first stage and the deceleration portion 42 of the second stage. More specifically, the control board 35 has an end portion of the stator 53 on the side closer to the second-stage reduction gear 42 (that is, the drive gear 423 and the driven gear 425) and the first-stage driven gear 415. It is located between the end portion on the side close to the second speed reduction portion 42 (that is, the drive gear 423 and the driven gear 425).
  • the end portion of the stator 53 means the end portion of the outermost member among the members such as teeth, windings, and laminated cores constituting the stator 53.
  • the third-stage reduction gear 43 includes a third-stage drive gear 433 that rotates integrally with the second reduction shaft 47, and a third-stage driven gear 435 that meshes with the third-stage drive gear 433.
  • the third-stage drive gear 433 is connected to the second reduction shaft 47 via the one-way clutch 44.
  • the one-way clutch 44 is a clutch mechanism configured to transmit a rotational force in only one direction.
  • the one-way clutch 44 is configured to transmit a rotational force in the direction of rotation accompanying the rotational drive of the motor shaft 51 and to cut off the transmission of the rotational force in the opposite direction.
  • the rotational force of the second reduction shaft 47 is transmitted to the third-stage drive gear 433 and the driven gear 435 via the one-way clutch 44, and is eventually transmitted to the output body 8.
  • the rotational force from the motor 5 and the rotational force generated by the driver pedaling the pedal 181 are transmitted to the output body 8 in combination.
  • the torque detector 33 is not limited to the magnetostrictive type, and it is also possible to adopt another sensing type.
  • Other sensing methods include, for example, a method using a strain sensor or a pressure sensor, and a mechanical type using a torsion bar or a potentiometer.
  • the control unit of the control board 35 has, for example, a microcomputer, and controls the operation of each element by executing a program stored in a storage unit such as a ROM (Read Only Memory).
  • a storage unit such as a ROM (Read Only Memory).
  • ROM Read Only Memory
  • the overall reduction ratio of the reduction mechanism 4 is set, for example, in the range of 30 to 35.
  • the overall reduction ratio of the reduction mechanism 4 is preferably set to 40 or less, more preferably 30 or less, 25 or less, or 20 or less.
  • the smaller the overall reduction ratio of the reduction mechanism 4, the smaller the load per tooth of each gear included in the reduction mechanism 4. Therefore, the wear of each gear included in the speed reduction mechanism 4 is reduced, and the durability is improved.
  • FIG. 4 is a cross-sectional view of a first modification of the motor unit 3 of the embodiment.
  • the position of the one-way clutch 49 incorporated in the speed reduction mechanism 4 is different from the position of the one-way clutch 44 shown in FIG.
  • the one-way clutch 44 that functions to cut off the power transmission in the deceleration mechanism 4 when the motor 5 is stopped is the third-stage drive gear 433 and the second deceleration shaft 47.
  • the one-way clutch 49 that functions to cut off the power transmission in the deceleration mechanism 4 when the motor 5 is stopped is the driven gear of the second stage. It is interposed between the 425 and the second reduction shaft 47.
  • the one-way clutch 49 is configured to transmit a rotational force in the direction of rotation accompanying the rotational drive of the motor shaft 51 and to cut off the transmission of the rotational force in the opposite direction.
  • FIG. 5 is a cross-sectional view of a second modification of the motor unit 3 of the embodiment.
  • the portion 94 of the unit case 9 that covers the stator 53 of the motor 5 is provided separately from the first divided body 91 and the second divided body 92.
  • the portion 94 is composed of, for example, a cup-shaped member formed of metal, and the opening edge portion of the member is fixed to the first divided body 91.
  • the second bearing 552 that rotatably supports the intermediate portion 515 in the axial direction of the motor shaft 51 and the bearing 461 that rotatably supports the first end portion 451 of the first reduction shaft 45 are formed in the first division 91. Have been placed.
  • the heat conductive member 95 in addition to the heat conductive member 95 being arranged between the control board 35 and the second divided body 92, the heat conductive member 95 is soft between the control board 35 and the first divided body 91.
  • the heat conductive member 96 of the above is arranged.
  • the first divided body 91 includes a heat radiating portion 915 having a shape protruding inward, and the plate-shaped heat conductive member 96 hits the heat radiating portion 915.
  • the heat radiating unit 915 has a flat plate shape parallel to the control substrate 35.
  • a heat conductive member 96 is sandwiched between the heat radiating portion 915 and the control board 35.
  • the heat conductive members 95, 96 and the heat radiating portions 925, 915 located on both sides of the control board 35 are within the range of the outer shape of the stator 53.
  • at least a part of the heat conductive member 95 is in a position overlapping with the stator 53, and at least a part of the heat conductive member 96 is in a position overlapping with the stator 53.
  • FIG. 6 is a cross-sectional view of a third modification of the motor unit 3 of the embodiment.
  • the basic configuration of the third modification is the same as that of the second modification, but in the third modification, the position of the one-way clutch 495 incorporated in the deceleration mechanism 4 is the position of the one-way clutch 44 of the second modification. Is different.
  • the crank so that the one-way clutch 495 that functions to cut off the power transmission in the reduction gear mechanism 4 when the motor 5 is stopped is interposed between the output body 8 and the driven gear 435 of the third stage. It is mounted coaxially with the shaft 6.
  • the one-way clutch 495 is configured to transmit a rotational force in the direction of rotation accompanying the rotational drive of the motor shaft 51 and to cut off the transmission of the rotational force in the opposite direction.
  • the motor unit 3 includes a parallel shaft gear type deceleration mechanism 4 for three-stage deceleration, but the deceleration mechanism 4 is not limited to three-stage deceleration. It may be a deceleration mechanism of 1-step deceleration, 2-step deceleration, or 4-step deceleration.
  • the driven gear provided to mesh with the drive gear that rotates integrally with the motor shaft is formed using polyacetal, which has the effect of suppressing noise during drive. , The effect that the wear of the gear is suppressed can be obtained.
  • the second-stage and third-stage driven gears 425 are added to the first-stage driven gear 415.
  • 435 can be formed of polyacetal. If the speed reduction mechanism 4 has four-stage deceleration, at least one of the second to fourth-stage driven gears can be formed of polyacetal in addition to the first-stage driven gear. If the speed reduction mechanism 4 has a two-stage deceleration as in the fourth modification, the second-stage driven gear 425 can be formed of polyacetal in addition to the first-stage driven gear 415.
  • the rotational force transmitted through the deceleration mechanism 4 and the rotational force of the crank shaft 6 are combined by the output body 8 arranged on the outer periphery of the crank shaft 6.
  • This is a so-called single-axis motor unit, but the present invention is not limited to this, and a conventionally known two-axis motor unit may be used.
  • the two-axis motor unit is a motor unit in which the output body 8 is composed of a first output body and a second output body.
  • the rotational force of the crank shaft 6 is transmitted to the first output body arranged on the outer periphery of the crank shaft 6, and the rotational force transmitted through the deceleration mechanism 4 is different from the crank shaft 6.
  • the electric bicycle 1 of one embodiment is a so-called electrically assisted bicycle, but is not limited to this, and may be an electric bicycle capable of rotationally driving the wheels 11 only by the rotational force of the motor 5.
  • the electric bicycle of one embodiment includes two wheels 11, the number of wheels 11 is not particularly limited, and for example, three wheels 11 may be provided.
  • the driven gear (415) having a high rotation speed among the reduction mechanism (4) attention is paid to the driven gear (415) having a high rotation speed among the reduction mechanism (4), and the driven gear (415) is formed of polyacetal. Since polyacetal has the highest self-lubricating property among the resins, the effect of suppressing the wear of the driven gear (415) having a high rotation speed, suppressing the noise during driving, and increasing the durability can be obtained. As a result, according to the motor unit (3) of the first aspect, the quietness and durability of the motor unit (3) are enhanced.
  • the motor unit (3) of the third aspect is realized by the combination with the first aspect.
  • the deceleration mechanism (4) is a parallel shaft gear type deceleration mechanism for three-stage deceleration.
  • the deceleration mechanism (4) since the deceleration mechanism (4) has three-stage deceleration, the reduction ratio of each stage can be suppressed, and the rotation speed is higher than that of the deceleration mechanism (4).
  • the load per tooth of the drive gear (413) and the driven gear (415) in the stage is reduced, and the teeth of the drive gear (413) and the driven gear (415) are less likely to break and the strength is increased.
  • the motor unit (3) of the fourth aspect is realized by the combination with the first aspect.
  • the deceleration mechanism (4) is a two-stage deceleration parallel shaft gear type deceleration mechanism.
  • the deceleration mechanism (4) since the deceleration mechanism (4) has two-stage deceleration, the reduction ratio of each stage can be suppressed, and the rotation speed is higher than that of the deceleration mechanism (4).
  • the load per tooth of the drive gear (413) and the driven gear (415) in the stage is reduced, and the teeth of the drive gear (413) and the driven gear (415) are less likely to break and the strength is increased.
  • the motor unit (3) of the sixth aspect is realized by the combination with any one of the first to the fourth aspects.
  • the motor unit (3) of the sixth aspect further includes a control board (35).
  • the reduction gear (4) has a first reduction shaft (45) that rotates integrally with the driven gear (415) and a second-stage drive gear (423) that rotates integrally with the first reduction shaft (45). Further included.
  • the motor (5) further has a stator (53). In the axial direction of the first reduction gear (45), the end of the stator (53) on the side closer to the second stage drive gear (423) and the second stage drive gear (423) of the driven gear (415). ),
  • the control board (35) is located between the end and the end.
  • the space in the unit can be effectively utilized and the occurrence of dead space can be suppressed. Therefore, the size of the motor unit (3) can be reduced.
  • the motor unit (3) of the seventh aspect is realized by the combination with any one of the first to the fourth aspects.
  • the deceleration mechanism (4) rotates integrally with the first deceleration shaft (45) that rotates integrally with the driven gear (415) and the first deceleration shaft (45).
  • the second deceleration that rotates integrally with the second-stage drive gear (423), the second-stage driven gear (425) that meshes with the second-stage drive gear (423), and the second-stage driven gear (425).
  • the motor unit (3) of the eighth aspect is realized by the combination with any one of the first to seventh aspects.
  • the motor unit (3) of the eighth aspect further includes a speed change mechanism (31) that decelerates or accelerates the rotation of the crank shaft (6) and transmits the rotation to the output body (8).
  • the rotation of the crank shaft (6) by human power can be changed and transmitted to the output body (8).
  • the motor unit (3) of the ninth aspect is realized by the combination with any one of the first to eighth aspects.
  • the reduction ratio of the reduction mechanism (4) is 40 or less.
  • the quietness and durability are enhanced in the motor unit (3) having a reduction ratio of 40 or less.
  • the motor unit (3) of the tenth aspect is realized by the combination with any one of the first to ninth aspects.
  • the motor unit (3) of the tenth aspect further includes a first bearing (551) and a second bearing (552) that support the motor shaft (51).
  • the distance between the second bearing (552) and the drive gear (413) is closer than the distance between the first bearing (551) and the drive gear (413).
  • the inner diameter of the second bearing (552) is larger than the inner diameter of the first bearing (551).
  • the rigidity of the entire configuration that supports the motor shaft (51) having a high rotation speed is increased. Therefore, the accuracy of meshing between the drive gear (413) and the driven gear (415) is improved.
  • the motor unit (3) of the eleventh aspect is realized by the combination with any one of the first to tenth aspects.
  • the drive gear (413) is formed by plastic working a part of the motor shaft (51).
  • the motor unit (3) of the twelfth aspect is realized by the combination with any one of the first to eleventh aspects.
  • the drive gear (413) is shot peened, air blasted or coated.
  • the surface roughness of the surface of the drive gear (413) is improved, and the slipperiness of the surface of the drive gear (413) is enhanced. Therefore, the frictional resistance between the drive gear (413) and the driven gear (415) is reduced, the noise during driving is suppressed, and the wear of the driven gear (415) is suppressed. Be done. Further, in the motor unit (3) of the twelfth aspect, the effect of improving the wear resistance of the drive gear (413) and the effect of improving the heat dissipation can be obtained.
  • the motor unit (3) of the thirteenth aspect is realized by the combination with any one of the first to the twelfth aspects.
  • the drive gear (413) and the driven gear (415) are oblique gears that mesh with each other.
  • the meshing ratio of the drive gear (413) and the driven gear (415) is increased.
  • the material of the driven gear (415) is polyacetal having a property of relatively low heat resistance, but since it becomes easy to stir the surrounding air during the rotation of the driven gear (415), the driven gear (415) The heat dissipation of is enhanced.
  • the motor unit (3) of the fourteenth aspect is realized by the combination with the thirteenth aspect.
  • the drive gear (413) and the driven gear (415) are oblique gears having a helix angle in the range of 10 ° to 45 °.
  • the motor unit (3) of the fifteenth aspect is realized by the combination with any one of the first to the fourteenth aspects.
  • the width of the meshing portion between the drive gear (413) and the driven gear (415) is set to 10 mm or more.
  • the meshing of the drive gear (413) and the driven gear (415) can be ensured, and quietness and durability can be improved.
  • the motor unit (3) of the sixteenth aspect is realized by the combination with any one of the first to fifteenth aspects.
  • the module of the drive gear (413) is 0.8 mm or more.
  • the motor unit (3) of the 17th aspect is realized by the combination with any one of the 1st to 16th aspects.
  • the reduction ratio of the reduction unit (41) composed of the drive gear (413) and the driven gear (415) is 10 or less.
  • the motor unit (3) of the eighteenth aspect is realized by the combination with any one of the first to the seventeenth aspects.
  • the number of teeth of the drive gear (413) is 2 or more and 6 or less.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Transportation (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermal Sciences (AREA)
  • Gear Transmission (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
  • Gears, Cams (AREA)

Abstract

Provided are a motor unit made to be quieter and more durable, and an electric automobile comprising said motor unit. A motor unit 3 is used in an electric automobile, and this motor unit comprises a crankshaft 6 driven by input, a motor 5 having a motor shaft 51, an output body 8 that outputs the rotation of the crankshaft 6,and a reduction mechanism 4 that reduces and transmits the rotation of the motor shaft 51. The reduction mechanism 4 includes a drive gear 413 that rotates integrally with the motor shaft 51, and a driven gear 415 that meshes with the drive gear 413. Within the reduction mechanism 4, at least the material of the driven gear 415 is polyacetal.

Description

モーターユニット及び電動自転車Motor unit and electric bicycle
　本開示は、モーターユニット及び電動自転車に関する。 This disclosure relates to motor units and electric bicycles.
　特許文献１には、モーターユニットを備えた電動自転車（詳細には電動アシスト自転車）が、記載されている。このモーターユニットでは、外殻となるユニットケースに、モーターと減速機構とが収納されている。 Patent Document 1 describes an electric bicycle equipped with a motor unit (specifically, an electrically assisted bicycle). In this motor unit, the motor and the deceleration mechanism are housed in the unit case which is the outer shell.
国際公開第２０１４／００９９９５号International Publication No. 2014/099995
　上記モーターユニットにおいては、モーターユニットの静音性と耐久性において改善の余地がある。 In the above motor unit, there is room for improvement in the quietness and durability of the motor unit.
　本開示は、静音性と耐久性を高めたモーターユニットとこれを備えた電動自転車を提供することを、目的とする。 The purpose of this disclosure is to provide a motor unit with improved quietness and durability and an electric bicycle equipped with the motor unit.
　本開示の一態様に係るモーターユニットは、電動自転車に用いられるモーターユニットであって、人力で駆動されるクランク軸と、モーター軸を有するモーターと、前記クランク軸の回転を出力する出力体と、前記モーター軸の回転を減速して前記出力体に伝達する減速機構と、を備える。前記減速機構は、前記モーター軸と一体に回転する駆動歯車と、前記駆動歯車に噛み合う従動歯車と、を含む。前記減速機構のうち少なくとも前記従動歯車の材料は、ポリアセタールである。 The motor unit according to one aspect of the present disclosure is a motor unit used for an electric bicycle, and includes a crank shaft driven by human power, a motor having a motor shaft, and an output body that outputs the rotation of the crank shaft. A deceleration mechanism for decelerating the rotation of the motor shaft and transmitting the rotation to the output body is provided. The reduction mechanism includes a drive gear that rotates integrally with the motor shaft and a driven gear that meshes with the drive gear. Of the reduction mechanisms, at least the material of the driven gear is polyacetal.
　本開示の一態様に係る電動自転車は、前記一態様に係る前記モーターユニットと、前記モーターユニットの前記モーターの回転力が伝えられる車輪と、を具備する。 The electric bicycle according to one aspect of the present disclosure includes the motor unit according to the one aspect and wheels to which the rotational force of the motor of the motor unit is transmitted.
図１は、一実施形態の電動自転車の側面図である。FIG. 1 is a side view of an electric bicycle according to an embodiment. 図２は、同上の電動自転車が備えるモーターユニットの要部の側面図である。FIG. 2 is a side view of a main part of a motor unit included in the same electric bicycle. 図３は、図２のＡ－Ａ線断面図である。FIG. 3 is a cross-sectional view taken along the line AA of FIG. 図４は、同上のモーターユニットの第１変形例の断面図である。FIG. 4 is a cross-sectional view of a first modification of the same motor unit. 図５は、同上のモーターユニットの第２変形例の断面図である。FIG. 5 is a cross-sectional view of a second modification of the same motor unit. 図６は、同上のモーターユニットの第３変形例の断面図である。FIG. 6 is a cross-sectional view of a third modification of the same motor unit. 図７は、同上のモーターユニットの第４変形例の断面図である。FIG. 7 is a cross-sectional view of a fourth modification of the same motor unit.
　［一実施形態］
　（電動自転車の全体構成）
　一実施形態の電動自転車１は、電動アシスト自転車である。一実施形態の電動自転車１は、フレーム１０と、フレーム１０に固定されたモーターユニット３と、フレーム１０に回転可能に連結された二つの車輪１１とを具備する。二つの車輪１１は、前輪１１１と後輪１１２である。二つの車輪１１のうち後輪１１２が、モーターユニット３から出力される駆動力によって回転駆動される。 [One Embodiment]
(Overall configuration of electric bicycle)
The electric bicycle 1 of one embodiment is an electrically assisted bicycle. The electric bicycle 1 of one embodiment includes a frame 10, a motor unit 3 fixed to the frame 10, and two wheels 11 rotatably connected to the frame 10. The two wheels 11 are a front wheel 111 and a rear wheel 112. Of the two wheels 11, the rear wheel 112 is rotationally driven by the driving force output from the motor unit 3.
　本文において用いる前後、左右、上下の各方向は、電動自転車１の運転者を基準として定義される。運転者が電動自転車１に乗って進行する方向が前方、これの反対側が後方である。運転者から見て左の方向が左方、運転者から見て右の方向が右方である。以下、各構成について詳しく説明する。 The front-back, left-right, and up-down directions used in the text are defined based on the driver of the electric bicycle 1. The direction in which the driver rides on the electric bicycle 1 is the front, and the opposite side is the rear. The left direction when viewed from the driver is the left, and the right direction when viewed from the driver is the right. Hereinafter, each configuration will be described in detail.
　（フレーム）
　図１に示すように、フレーム１０は、ヘッドパイプ１０１、上パイプ１０２、下パイプ１０３、立パイプ１０４、シートステー１０５、チェーンステー１０６及びブラケット１０７を有する。 (flame)
As shown in FIG. 1, the frame 10 has a head pipe 101, an upper pipe 102, a lower pipe 103, a vertical pipe 104, a seat stay 105, a chain stay 106, and a bracket 107.
　フレーム１０（つまりフレーム１０を構成する上記の各部）は、アルミニウム、ステンレス鋼等の金属で形成されるが、非金属を一部に含んでもよい。フレーム１０全体が非金属で形成されてもよく、フレーム１０の材質は特に限定されない。 The frame 10 (that is, each of the above parts constituting the frame 10) is made of a metal such as aluminum or stainless steel, but may contain a non-metal as a part. The entire frame 10 may be made of non-metal, and the material of the frame 10 is not particularly limited.
　ヘッドパイプ１０１には、ハンドルポスト１２が回転可能に挿し通されている。ハンドルポスト１２の下端部には、フロントフォーク１２１が形成されている。フロントフォーク１２１には、前輪１１１が回転可能に取り付けられている。ハンドルポスト１２の上端部には、ハンドルバー１２２が固定されている。 A handle post 12 is rotatably inserted through the head pipe 101. A front fork 121 is formed at the lower end of the handle post 12. A front wheel 111 is rotatably attached to the front fork 121. A handlebar 122 is fixed to the upper end of the handlepost 12.
　ヘッドパイプ１０１には、上パイプ１０２の前端部が固定されている。上パイプ１０２の後端部は、立パイプ１０４に固定されている。立パイプ１０４の上端開口には、サドル１３から下方に延びるパイプ１３２が挿入されている。このパイプ１３２が立パイプ１０４に固定されることで、サドル１３が固定される。立パイプ１０４の下端部には、ブラケット１０７が固定されている。 The front end of the upper pipe 102 is fixed to the head pipe 101. The rear end of the upper pipe 102 is fixed to the vertical pipe 104. A pipe 132 extending downward from the saddle 13 is inserted into the upper end opening of the vertical pipe 104. By fixing the pipe 132 to the vertical pipe 104, the saddle 13 is fixed. A bracket 107 is fixed to the lower end of the vertical pipe 104.
　ヘッドパイプ１０１には、下パイプ１０３の前端部が更に固定されている。下パイプ１０３の後端部には、ブラケット１０７が固定されている。 The front end of the lower pipe 103 is further fixed to the head pipe 101. A bracket 107 is fixed to the rear end of the lower pipe 103.
　ブラケット１０７には、モーターユニット３が固定されている。ブラケット１０７の後端部には、チェーンステー１０６の前端部が固定されている。 The motor unit 3 is fixed to the bracket 107. The front end of the chain stay 106 is fixed to the rear end of the bracket 107.
　上パイプ１０２の後端部には、シートステー１０５の前端部が固定されている。シートステー１０５の後端部は、チェーンステー１０６の後端部に連結されており、この連結部分に後輪１１２が回転可能に装着されている。下パイプ１０３には、モーターユニット３に電力を供給するためのバッテリー１５が、着脱可能に装着されている。 The front end of the seat stay 105 is fixed to the rear end of the upper pipe 102. The rear end portion of the seat stay 105 is connected to the rear end portion of the chain stay 106, and the rear wheel 112 is rotatably attached to the connecting portion. A battery 15 for supplying electric power to the motor unit 3 is detachably attached to the lower pipe 103.
　（モーターユニット）
　次に、モーターユニット３について説明する。 (Motor unit)
Next, the motor unit 3 will be described.
　図２に示すように、モーターユニット３の外殻の要部は、ユニットケース９で形成されている。ユニットケース９には、車輪１１を回転駆動させるための駆動源であるモーター５が取り付けられている。図３に示すように、ユニットケース９には、モーター５と、モーター５の回転を制御する制御基板３５とに加えて、クランク軸６、入力体７、出力体８、減速機構４等が収容されている。 As shown in FIG. 2, the main part of the outer shell of the motor unit 3 is formed by the unit case 9. A motor 5 which is a drive source for rotationally driving the wheels 11 is attached to the unit case 9. As shown in FIG. 3, in addition to the motor 5 and the control board 35 that controls the rotation of the motor 5, the unit case 9 houses a crank shaft 6, an input body 7, an output body 8, a deceleration mechanism 4, and the like. Has been done.
　（ユニットケース）
　ユニットケース９は、ユニットケース９の左右方向の半部を形成する第１分割体９１と、ユニットケース９の左右方向の別の半部を構成する第２分割体９２と、第１分割体９１と第２分割体９２の間に挟み込まれる中間部材９３とを含む。第１分割体９１と第２分割体９２とが組み合わさって形成される中空部分に、中間部材９３と制御基板３５とが収容されている。 (Unit case)
The unit case 9 includes a first divided body 91 forming a left-right half portion of the unit case 9, a second divided body 92 forming another left-right half portion of the unit case 9, and a first divided body 91. And an intermediate member 93 sandwiched between the second divided body 92. The intermediate member 93 and the control board 35 are housed in a hollow portion formed by combining the first divided body 91 and the second divided body 92.
　中間部材９３は、第１分割体９１及び第２分割体９２とは別部材であるが、中間部材９３が、第１分割体９１または第２分割体９２と一体に形成されてもよい。 The intermediate member 93 is a separate member from the first divided body 91 and the second divided body 92, but the intermediate member 93 may be integrally formed with the first divided body 91 or the second divided body 92.
　制御基板３５と第２分割体９２との間には、軟質の熱伝導性部材９５が配置されている。第２分割体９２は、内側に突出した放熱部９２５を含んでおり、この放熱部９２５に、板状の熱伝導性部材９５が当たっている。放熱部９２５は、第２分割体９２の周囲の部分よりも内側に凹んだ形状を有する。凹んだ形状の放熱部９２５の底部分に対して、熱伝導性部材９５が当たっている。 A soft heat conductive member 95 is arranged between the control board 35 and the second divided body 92. The second divided body 92 includes a heat radiating portion 925 protruding inward, and the plate-shaped heat conductive member 95 hits the heat radiating portion 925. The heat radiating portion 925 has a shape recessed inward from the peripheral portion of the second divided body 92. The heat conductive member 95 hits the bottom portion of the heat radiating portion 925 having a concave shape.
　モーター軸５１の軸方向に見たとき、放熱部９２５と熱伝導性部材９５は、後述のステーター５３の外形の範囲内にある。熱伝導性部材９５の全部がステーター５３の外形の範囲内にあってもよいし、熱伝導性部材９５の一部がステーター５３の外形の範囲内にあってもよい。モーター軸５１の軸方向に見たとき、熱伝導性部材９５の少なくとも一部は、ステーター５３と重なる位置にあることが好ましい。 When viewed in the axial direction of the motor shaft 51, the heat radiating portion 925 and the heat conductive member 95 are within the range of the outer shape of the stator 53 described later. The entire heat conductive member 95 may be within the range of the outer shape of the stator 53, or a part of the heat conductive member 95 may be within the range of the outer shape of the stator 53. When viewed in the axial direction of the motor shaft 51, it is preferable that at least a part of the heat conductive member 95 is located at a position overlapping with the stator 53.
　一実施形態のモーターユニット３において、放熱部９２５と熱伝導性部材９５は、制御基板３５を挟んで一方の一側（詳細には、第２分割体９２が位置する側）にだけ設けられているが、制御基板３５を挟んで両側（つまり、第２分割体９２が位置する側と第１分割体９１が位置する側の両方）に設けられてもよい。 In the motor unit 3 of one embodiment, the heat radiating portion 925 and the heat conductive member 95 are provided only on one side (specifically, the side on which the second divided body 92 is located) with the control board 35 interposed therebetween. However, they may be provided on both sides of the control board 35 (that is, both the side where the second divided body 92 is located and the side where the first divided body 91 is located).
　（モーター）
　モーター５は、円柱状のモーター軸５１と、モーター軸５１と一体に回転するようにモーター軸５１に結合されたローター５２と、ローター５２を囲んで位置する円筒状のステーター５３とを有する。 (motor)
The motor 5 has a cylindrical motor shaft 51, a rotor 52 coupled to the motor shaft 51 so as to rotate integrally with the motor shaft 51, and a cylindrical stator 53 located so as to surround the rotor 52.
　第１分割体９１の内面には、軸受５５１を配置するための凹部９１２が形成されている。軸受５５１は、モーター軸５１の軸方向の第１端部５１１を回転可能に支持する軸受である。中間部材９３には、モーター軸５１が挿し通される貫通孔９３１と、軸受５５２を配置するための凹部９３２とが形成されている。凹部９３２は、貫通孔９３１の内周面に形成されている。軸受５５２は、モーター軸５１の軸方向の中間部分５１５を、回転可能に支持する。 A recess 912 for arranging the bearing 551 is formed on the inner surface of the first split body 91. The bearing 551 is a bearing that rotatably supports the first end portion 511 of the motor shaft 51 in the axial direction. The intermediate member 93 is formed with a through hole 931 through which the motor shaft 51 is inserted and a recess 932 for arranging the bearing 552. The recess 932 is formed on the inner peripheral surface of the through hole 931. The bearing 552 rotatably supports the axially intermediate portion 515 of the motor shaft 51.
　一実施形態のモーターユニット３において、モーター軸５１の軸方向の第２端部５１２は、軸受によって支持されていない。モーター軸５１の第１端部５１１と第２端部５１２は、モーター軸５１の軸方向において互いに反対に位置する。 In the motor unit 3 of one embodiment, the second end portion 512 in the axial direction of the motor shaft 51 is not supported by the bearing. The first end portion 511 and the second end portion 512 of the motor shaft 51 are located opposite to each other in the axial direction of the motor shaft 51.
　以下においては区別のために、軸受５５１を第１軸受５５１と称し、軸受５５２を第２軸受５５２と称する。第１軸受５５１と第２軸受５５２は、ともにリング状の深溝玉軸受である。 In the following, for the sake of distinction, the bearing 551 is referred to as the first bearing 551, and the bearing 552 is referred to as the second bearing 552. Both the first bearing 551 and the second bearing 552 are ring-shaped deep groove ball bearings.
　第２軸受５５２の内径は、第１軸受５５１の内径よりも大きく設定されている。第１軸受５５１の内径は、７ｍｍから８ｍｍの範囲内で設定されることが好ましく、例えば７ｍｍまたは８ｍｍである。第２軸受５５２の内径は、１０ｍｍから１２ｍｍの範囲内で設定されることが好ましく、例えば１０ｍｍ、１１ｍｍまたは１２ｍｍである。第２軸受５５２の内径は、第１軸受５５１の外径よりも小さいことが好ましい。 The inner diameter of the second bearing 552 is set to be larger than the inner diameter of the first bearing 551. The inner diameter of the first bearing 551 is preferably set within the range of 7 mm to 8 mm, for example, 7 mm or 8 mm. The inner diameter of the second bearing 552 is preferably set within the range of 10 mm to 12 mm, for example, 10 mm, 11 mm or 12 mm. The inner diameter of the second bearing 552 is preferably smaller than the outer diameter of the first bearing 551.
　第２軸受５５２と後述する１段目の駆動歯車４１３との間の距離は、第１軸受５５１と１段目の駆動歯車４１３との間の距離よりも、近い。 The distance between the second bearing 552 and the first-stage drive gear 413, which will be described later, is shorter than the distance between the first bearing 551 and the first-stage drive gear 413.
　このように、第１軸受５５１と第２軸受５５２のうち駆動歯車４１３（及び後述の従動歯車４１５）に近い側の第２軸受５５２が、第１軸受５５１よりも大きな内径を有する比較的大型の軸受であることで、モーター軸５１を支持する構成全体の剛性が高まり、その結果として、１段目の駆動歯車４１３と従動歯車４１５との噛み合いの精度が高まるという利点がある。 As described above, the second bearing 552 of the first bearing 551 and the second bearing 552 on the side closer to the drive gear 413 (and the driven gear 415 described later) has a relatively large inner diameter larger than that of the first bearing 551. The bearing has the advantage that the rigidity of the entire configuration that supports the motor shaft 51 is increased, and as a result, the accuracy of meshing between the first-stage drive gear 413 and the driven gear 415 is improved.
　加えて、第２軸受５５２の内径が第１軸受５５１の外径よりも小さいことで、上記のようにモーター軸５１を支持する構成全体の剛性を高めつつ、モーターユニット３のコンパクト化を図ることができる。 In addition, since the inner diameter of the second bearing 552 is smaller than the outer diameter of the first bearing 551, the motor unit 3 can be made compact while increasing the rigidity of the entire configuration that supports the motor shaft 51 as described above. Can be done.
　（クランク軸）
　クランク軸６は、ユニットケース９に収容された状態で、自身の軸線まわりに回転可能である。第１分割体９１には、クランク軸６が挿し通される貫通孔９１１が、形成されている。第２分割体９２には、クランク軸６が挿し通される貫通孔９２１が、形成されている。 (Crank shaft)
The crank shaft 6 can rotate around its own axis while being housed in the unit case 9. A through hole 911 through which the crank shaft 6 is inserted is formed in the first divided body 91. A through hole 921 through which the crank shaft 6 is inserted is formed in the second divided body 92.
　クランク軸６の両端部には、クランクアーム１８（図１参照）が固定される。クランクアーム１８の先端部には、ペダル１８１が回転可能に取り付けられる。運転者は、ペダル１８１を漕ぐことにより、クランク軸６に対して人力の回転力を加えることができる。 Crank arms 18 (see FIG. 1) are fixed to both ends of the crank shaft 6. A pedal 181 is rotatably attached to the tip of the crank arm 18. The driver can apply a human-powered rotational force to the crank shaft 6 by pedaling the pedal 181.
　（入力体）
　入力体７は、ユニットケース９内において、クランク軸６の外周面に沿って配置されている。入力体７は筒状の部材であり、クランク軸６と一体に回転する。 (Input body)
The input body 7 is arranged in the unit case 9 along the outer peripheral surface of the crank shaft 6. The input body 7 is a cylindrical member and rotates integrally with the crank shaft 6.
　入力体７は、第１入力体７１と第２入力体７２とに分割されている。第２入力体７２は、第２分割体９２内でクランク軸６に連結されている。第１入力体７１は、第１分割体９１内においてワンウェイクラッチを介して出力体８に連結され、出力体８に回転力を伝達するように構成されている。一実施形態のモーターユニット３においては、第１入力体７１と第２入力体７２とが別体に構成されているが、第１入力体７１と第２入力体７２とが一体に構成されてもよい。 The input body 7 is divided into a first input body 71 and a second input body 72. The second input body 72 is connected to the crank shaft 6 in the second split body 92. The first input body 71 is connected to the output body 8 via a one-way clutch in the first split body 91, and is configured to transmit a rotational force to the output body 8. In the motor unit 3 of one embodiment, the first input body 71 and the second input body 72 are separately configured, but the first input body 71 and the second input body 72 are integrally configured. May be good.
　（出力体）
　出力体８は筒状の部材であり、クランク軸６の外周面に沿って回転可能に配置されている。出力体８の一端部は、第１分割体９１の貫通孔９１１を通って、ユニットケース９の外に突出している。 (Output body)
The output body 8 is a cylindrical member, and is rotatably arranged along the outer peripheral surface of the crank shaft 6. One end of the output body 8 projects to the outside of the unit case 9 through the through hole 911 of the first divided body 91.
　出力体８のうちユニットケース９から突出した部分には、前側のスプロケット１９１が固定されている。前側のスプロケット１９１は、出力体８と一体に回転する。図１に示すように、後輪１１２のハブには、後側のスプロケット１９２が固定されている。前側のスプロケット１９１と後側のスプロケット１９２との間には、チェーン１９３が掛け回されている。 The front sprocket 191 is fixed to the portion of the output body 8 that protrudes from the unit case 9. The front sprocket 191 rotates integrally with the output body 8. As shown in FIG. 1, a rear sprocket 192 is fixed to the hub of the rear wheel 112. A chain 193 is hung between the front sprocket 191 and the rear sprocket 192.
　図３に示すように、出力体８は、ウェブ８１とリム８２とを一体に有する。ウェブ８１は、出力体８の径方向の外側に向けて突出している。リム８２は、ウェブ８１の径方向の外端部から連続している。リム８２が減速機構４に対して機械的に連結されることで、減速機構４の回転力が出力体８にまで伝達される。 As shown in FIG. 3, the output body 8 has the web 81 and the rim 82 integrally. The web 81 projects outward in the radial direction of the output body 8. The rim 82 is continuous from the radial outer end of the web 81. By mechanically connecting the rim 82 to the deceleration mechanism 4, the rotational force of the deceleration mechanism 4 is transmitted to the output body 8.
　（減速機構）
　減速機構４は、モーター５の回転を減速して出力体８にまで伝達するように構成されている。減速機構４は、１段目の減速部４１と、第１減速軸４５と、２段目の減速部４２と、第２減速軸４７と、３段目の減速部４３とを含んだ、３段減速の平行軸歯車式の減速機構である。ユニットケース９内において、モーター軸５１、第１減速軸４５、第２減速軸４７、及びクランク軸６は、互いに平行に位置する。 (Deceleration mechanism)
The deceleration mechanism 4 is configured to decelerate the rotation of the motor 5 and transmit it to the output body 8. The deceleration mechanism 4 includes a first-stage deceleration unit 41, a first-stage deceleration shaft 45, a second-stage deceleration unit 42, a second-stage deceleration shaft 47, and a third-stage deceleration unit 43. It is a parallel shaft gear type deceleration mechanism for step deceleration. In the unit case 9, the motor shaft 51, the first reduction shaft 45, the second reduction shaft 47, and the crank shaft 6 are located parallel to each other.
　ここで、本願における減速機構４の減速段数を定義する。 Here, the number of deceleration stages of the deceleration mechanism 4 in the present application is defined.
　減速機構４の減速段数は、モーター軸５１から出力体８に至るまでの動力伝達経路における、回転数減少が実現される部分（つまり減速部）の数である。減速部は、互いに動力伝達可能に連結された複数の回転体を含む。減速機構４においては、これら複数の回転体を通じて回転が伝達される際に、回転数減少が実現される。回転体は、例えば歯車、スプロケット等である。複数の回転体は、互いに接触して回転を伝達してもよいし、チェーン、ベルト等の動力伝達体を介して回転を伝達してもよい。上記の定義に基づけば、一実施形態のモーターユニット３が備える減速機構４は、３つの減速部（つまり、１段目、２段目及び３段目の減速部４１，４２，４３）を有する３段減速の減速機構である。 The number of deceleration stages of the deceleration mechanism 4 is the number of portions (that is, deceleration portions) in the power transmission path from the motor shaft 51 to the output body 8 where the rotation speed is reduced. The speed reducer includes a plurality of rotating bodies connected to each other so as to be able to transmit power. In the speed reduction mechanism 4, when the rotation is transmitted through these plurality of rotating bodies, the rotation speed is reduced. The rotating body is, for example, a gear, a sprocket, or the like. The plurality of rotating bodies may come into contact with each other to transmit rotation, or may transmit rotation via a power transmission body such as a chain or a belt. Based on the above definition, the deceleration mechanism 4 included in the motor unit 3 of one embodiment has three deceleration units (that is, first-stage, second-stage, and third- stage deceleration units 41, 42, 43). It is a deceleration mechanism with three-stage deceleration.
　（１段目の減速部）
　１段目の減速部４１は、モーター軸５１と一体に回転する１段目の駆動歯車４１３と、１段目の駆動歯車４１３に噛み合う１段目の従動歯車４１５とを含む。 (First stage deceleration section)
The first-stage reduction gear 41 includes a first-stage drive gear 413 that rotates integrally with the motor shaft 51, and a first-stage driven gear 415 that meshes with the first-stage drive gear 413.
　１段目の駆動歯車４１３は、金属製のモーター軸５１の一部を塑性加工して形成した歯部で、構成されている。１段目の駆動歯車４１３は、モーター軸５１の一部であり、金属製である。 The first-stage drive gear 413 is composed of tooth portions formed by plastic working a part of a metal motor shaft 51. The first-stage drive gear 413 is a part of the motor shaft 51 and is made of metal.
　モーター軸５１は、第１軸受５５１に支持される第１端部５１１と、第２軸受５５２に支持される中間部分５１５と、中間部分５１５よりも第１端部５１１から離れた部分５１３とを含み、この部分５１３の外周面に、塑性加工によって１段目の駆動歯車４１３が形成されている。 The motor shaft 51 has a first end portion 511 supported by the first bearing 551, an intermediate portion 515 supported by the second bearing 552, and a portion 513 farther from the first end portion 511 than the intermediate portion 515. A first-stage drive gear 413 is formed on the outer peripheral surface of this portion 513 by plastic working.
　上記の塑性加工は、例えば、鍛造加工または転造加工である。これらの塑性加工によれば、モーター軸５１を削って駆動歯車４１３を形成する場合に比べて、良好な面粗さが得られる。そのため、１段目の駆動歯車４１３と従動歯車４１５との間の摩擦抵抗が低減され、駆動時の騒音が抑制されるという効果と、従動歯車４１５の摩耗が抑制されるという効果が得られる。 The above plastic working is, for example, forging or rolling. According to these plastic workings, better surface roughness can be obtained as compared with the case where the motor shaft 51 is shaved to form the drive gear 413. Therefore, the frictional resistance between the first-stage drive gear 413 and the driven gear 415 is reduced, the noise during driving is suppressed, and the wear of the driven gear 415 is suppressed.
　１段目の駆動歯車４１３には、ショットピーニング、エアブラストまたはコーティングが施されることが好ましい。 It is preferable that the first-stage drive gear 413 is provided with shot peening, air blasting or coating.
　ショットピーニングには、例えば、ハードショットピーニング、セミハードショットピーニング、ＷＰＣ処理、二硫化モリブデンショットピーニング、及びシリウス加工が含まれる。駆動歯車４１３の表面にショットピーニングを施すことで、駆動歯車４１３の表面の面粗さが良化し、駆動歯車４１３の表面の滑り性が高まる。そのため、１段目の駆動歯車４１３と従動歯車４１５との間の摩擦抵抗が低減され、駆動時の騒音が抑制されるという効果と、従動歯車４１５の摩耗が抑制されるという効果が得られる。また、駆動歯車４１３の耐摩耗性が向上し、駆動歯車４１３と従動歯車４１５の噛み合い部分の発熱が抑えられるという効果が得られる。 Shot peening includes, for example, hard shot peening, semi-hard shot peening, WPC treatment, molybdenum disulfide shot peening, and Sirius processing. By applying shot peening to the surface of the drive gear 413, the surface roughness of the surface of the drive gear 413 is improved, and the slipperiness of the surface of the drive gear 413 is enhanced. Therefore, the frictional resistance between the first-stage drive gear 413 and the driven gear 415 is reduced, the noise during driving is suppressed, and the wear of the driven gear 415 is suppressed. Further, the wear resistance of the drive gear 413 is improved, and the effect that heat generation of the meshing portion between the drive gear 413 and the driven gear 415 is suppressed can be obtained.
　エアブラストには、例えば、＃１００のメディアを用いたエアブラスト処理と、＃４００のメディアを用いたエアブラスト処理とが含まれる。駆動歯車４１３の表面にエアブラストが施されることで、駆動歯車４１３の表面の面粗さが良化し、駆動歯車４１３の表面の滑り性が高まる。そのため、１段目の駆動歯車４１３と従動歯車４１５との間の摩擦抵抗が低減され、駆動時の騒音が抑制されるという効果と、従動歯車４１５の摩耗が抑制されるという効果が得られる。 The air blast includes, for example, an air blast process using # 100 media and an air blast process using # 400 media. By applying air blast to the surface of the drive gear 413, the surface roughness of the surface of the drive gear 413 is improved, and the slipperiness of the surface of the drive gear 413 is enhanced. Therefore, the frictional resistance between the first-stage drive gear 413 and the driven gear 415 is reduced, the noise during driving is suppressed, and the wear of the driven gear 415 is suppressed.
　コーティングには、ＤＬＣ（Ｄｉａｍｏｎｄ－Ｌｉｋｅ　Ｃａｒｂｏｎ）コーティング、テフロン（登録商標）コーティング、ドライルーブ処理、アルマイト処理、硬質アルマイト処理、二硫化モリブデンコーティング、及び各種のめっき処理が含まれる。各種のめっき処理には、例えば、硬質クロムめっき、電解硬質炭化クロムめっき、三価クロメートめっき、ニッケルめっき、無電解ニッケルめっき、フッ素複合無電解ニッケルめっき、フッ素複合無電解ニッケルめっきの処理を施すことと、パーカー処理を施すこととが含まれる。 The coating includes DLC (Diamond-Like Carbon) coating, Teflon (registered trademark) coating, dry lube treatment, alumite treatment, hard alumite treatment, molybdenum disulfide coating, and various plating treatments. Various plating treatments include, for example, hard chrome plating, electrolytic hard chrome carbide plating, trivalent chromate plating, nickel plating, electroless nickel plating, fluorine composite electroless nickel plating, and fluorine composite electroless nickel plating. And applying Parker treatment.
　駆動歯車４１３の表面に上記のコーティングが施されることで、駆動歯車４１３の表面の面粗さが良化し、駆動歯車４１３の表面の滑り性が高まる。そのため、１段目の駆動歯車４１３と従動歯車４１５との間の摩擦抵抗が低減され、駆動時の騒音が抑制されるという効果と、従動歯車４１５の摩耗が抑制されるという効果が得られる。 By applying the above coating to the surface of the drive gear 413, the surface roughness of the surface of the drive gear 413 is improved, and the slipperiness of the surface of the drive gear 413 is enhanced. Therefore, the frictional resistance between the first-stage drive gear 413 and the driven gear 415 is reduced, the noise during driving is suppressed, and the wear of the driven gear 415 is suppressed.
　次に、１段目の従動歯車４１５について説明する。 Next, the driven gear 415 of the first stage will be described.
　１段目の従動歯車４１５は、１段目の駆動歯車４１３に噛み合うことで、モーター軸５１の回転駆動力を受けて回転する部材である。１段目の従動歯車４１５の外周面には、１段目の駆動歯車４１３と噛み合う複数の歯が形成されている。 The first-stage driven gear 415 is a member that rotates by receiving the rotational driving force of the motor shaft 51 by meshing with the first-stage drive gear 413. A plurality of teeth that mesh with the first-stage drive gear 413 are formed on the outer peripheral surface of the first-stage driven gear 415.
　１段目の従動歯車４１５は、樹脂を材料として筒状に成形された歯車である。樹脂は、具体的にはポリアセタールであるが、ナイロン等の他の樹脂を用いることも可能である。 The first-stage driven gear 415 is a gear formed into a cylindrical shape using resin as a material. The resin is specifically polyacetal, but other resins such as nylon can also be used.
　ポリアセタールは、自己潤滑性を有する材料である。１段目の従動歯車４１５をポリアセタールで成形することで、従動歯車４１５の摩耗が抑制され、駆動時の騒音が抑制されるという効果と、耐久性が高まるという効果が得られる。特に、減速機構４のなかでも回転数が高い１段目の減速部４１において、１段目の減速部４１に含まれる従動歯車４１５がポリアセタール製であることで、減速機構４の全体の騒音が効果的に抑制されるという効果と、減速機構４の全体の耐久性が効果的に高まるという効果が得られる。 Polyacetal is a self-lubricating material. By molding the driven gear 415 of the first stage with polyacetal, the wear of the driven gear 415 is suppressed, the noise during driving is suppressed, and the durability is enhanced. In particular, in the first-stage deceleration unit 41 having a high rotation speed among the deceleration mechanisms 4, the driven gear 415 included in the first-stage deceleration unit 41 is made of polyacetal, so that the noise of the entire deceleration mechanism 4 is reduced. The effect of being effectively suppressed and the effect of effectively increasing the overall durability of the deceleration mechanism 4 can be obtained.
　また、一般的に、減速機構に含まれる従動歯車は大径となって重量が嵩む傾向にあるが、一実施形態のモーターユニット３では、従動歯車４１５がポリアセタール等の樹脂で成形されていることによって、減速機構４の軽量化が実現され、ひいては電動自転車１の全体の軽量化が実現される。加えて、従動歯車４１５の軽量化によって、従動歯車４１５の回転モーメントが小さくなるので、モーター５による電動自転車１の俊敏な動作が実現される。 Further, in general, the driven gear included in the reduction gear tends to have a large diameter and increase in weight, but in the motor unit 3 of one embodiment, the driven gear 415 is formed of a resin such as polyacetal. As a result, the weight of the deceleration mechanism 4 is reduced, and the weight of the electric bicycle 1 is reduced as a whole. In addition, by reducing the weight of the driven gear 415, the rotational moment of the driven gear 415 becomes smaller, so that the agile operation of the electric bicycle 1 by the motor 5 is realized.
　ここで、従動歯車４１５の材料が仮にナイロンである場合と比較すると、従動歯車４１５の材料がポリアセタールである場合には、一層高い耐久性が得られるという利点と、比較的に安価で提供可能であるという利点がある。 Here, as compared with the case where the material of the driven gear 415 is nylon, when the material of the driven gear 415 is polyacetal, there is an advantage that higher durability can be obtained, and it can be provided at a relatively low cost. There is an advantage that there is.
　ポリアセタールは、その分子構造に基づいて、ホモポリマーとコポリマーの二種類に分類される。従動歯車４１５の材料には、ホモポリマーとコポリマーのどちらの種類のポリアセタールを用いることも可能である。 Polyacetal is classified into two types, homopolymer and copolymer, based on its molecular structure. It is possible to use either homopolymer or copolymer type polyacetal as the material for the driven gear 415.
　１段目の従動歯車４１５の内周面には、金属製の第１減速軸４５が固定されている。第１減速軸４５の第１端部４５１は、中間部材９３に配置された軸受４６１に、回転可能に支持されている。第１減速軸４５の第２端部４５２は、第２分割体９２に配置された軸受４６２に、回転可能に支持されている。第１減速軸４５の第１端部４５１と第２端部４５２は、互いに反対側に位置する。軸受４６１と軸受４６２は、ともにリング状の深溝玉軸受である。軸受４６１と軸受４６２の互いの内径は同一であり、軸受４６１と軸受４６２の互いの外径は同一である。 A first reduction shaft 45 made of metal is fixed to the inner peripheral surface of the driven gear 415 of the first stage. The first end portion 451 of the first reduction shaft 45 is rotatably supported by a bearing 461 arranged on the intermediate member 93. The second end portion 452 of the first reduction shaft 45 is rotatably supported by a bearing 462 arranged in the second split body 92. The first end portion 451 and the second end portion 452 of the first reduction shaft 45 are located on opposite sides of each other. Both the bearing 461 and the bearing 462 are ring-shaped deep groove ball bearings. The inner diameters of the bearings 461 and 462 are the same, and the outer diameters of the bearings 461 and 462 are the same.
　クランク軸６及びモーター軸５１の軸方向と直交する方向に見たとき、軸受４６１の少なくとも一部は、制御基板３５と重なる位置にある。 When viewed in a direction orthogonal to the axial direction of the crank shaft 6 and the motor shaft 51, at least a part of the bearing 461 is located at a position overlapping with the control board 35.
　金属製の第１減速軸４５は、樹脂製の従動歯車４１５に挿入された芯金として機能する。これにより、樹脂製である従動歯車４１５の強度は、一層高められている。また、従動歯車４１５の材料は、例えばナイロンと比較して耐熱性が低い性質を有するポリアセタールであるが、従動歯車４１５の放熱性は、金属製の第１減速軸４５を介して高められている。第１減速軸４５と従動歯車４１５はインサート成形等の一体成形で提供してもよいし、第１減速軸４５を従動歯車４１５の貫通孔に圧入することで提供してもよい。 The first reduction shaft 45 made of metal functions as a core metal inserted into the driven gear 415 made of resin. As a result, the strength of the driven gear 415 made of resin is further increased. Further, the material of the driven gear 415 is polyacetal having a property of lower heat resistance than, for example, nylon, but the heat dissipation of the driven gear 415 is enhanced via the first reduction shaft 45 made of metal. .. The first reduction shaft 45 and the driven gear 415 may be provided by integral molding such as insert molding, or the first reduction shaft 45 may be provided by press-fitting the first reduction shaft 45 into the through hole of the driven gear 415.
　以上の駆動歯車４１３と従動歯車４１５とで、１段目の減速部４１が構成されている。以下においては、１段目の駆動歯車４１３と従動歯車４１５の構造について、更に詳しく説明する。 The drive gear 413 and the driven gear 415 described above constitute the first-stage reduction gear 41. Hereinafter, the structures of the first-stage drive gear 413 and the driven gear 415 will be described in more detail.
　１段目の駆動歯車４１３と従動歯車４１５は、互いに噛み合う斜歯歯車である。駆動歯車４１３と従動歯車４１５とが斜歯歯車であることで、１段目の減速部４１の噛み合い率（つまり駆動歯車４１３と従動歯車４１５との噛み合い率）が高まるという利点がある。加えて、従動歯車４１５の材料は、例えばナイロンと比較して耐熱性が低い性質を有するポリアセタールであるが、従動歯車４１５が斜歯歯車であることから、従動歯車４１５の回転中に周囲の空気をかき混ぜやすく、従動歯車４１５の放熱性が高まるという利点がある。 The first-stage drive gear 413 and driven gear 415 are oblique tooth gears that mesh with each other. Since the drive gear 413 and the driven gear 415 are diagonal gears, there is an advantage that the meshing ratio of the first-stage reduction gear 41 (that is, the meshing ratio between the drive gear 413 and the driven gear 415) is increased. In addition, the material of the driven gear 415 is polyacetal having a property of lower heat resistance than, for example, nylon, but since the driven gear 415 is an oblique gear, the ambient air during the rotation of the driven gear 415. It has the advantage that it is easy to stir and the heat dissipation of the driven gear 415 is improved.
　駆動歯車４１３と従動歯車４１５は、２０°から２５°の範囲内のねじれ角を有するように設計された斜歯歯車であることが好ましいが、他の範囲内でねじれ角を設定することも可能である。斜歯歯車のねじれ角は、１０°以上に設定されることが好ましいが、１５°以上に設定されること、２０°以上に設定されること、または２５°以上に設定されることも好ましい。但し、ねじれ角が大きすぎると、従動歯車４１５が倒れるおそれがあるため、ねじれ角は４５°以下で設定されることが好ましい。そのため、ねじれ角は１０°から４５°の範囲内で設定されることが好ましく、２０°から２５°の範囲内で設定されることが更に好ましい。 The drive gear 413 and the driven gear 415 are preferably diagonal gears designed to have a helix angle in the range of 20 ° to 25 °, but the helix angle can be set in other ranges. Is. The helix angle of the oblique gear is preferably set to 10 ° or more, but is also preferably set to 15 ° or more, 20 ° or more, or 25 ° or more. However, if the helix angle is too large, the driven gear 415 may fall down, so the helix angle is preferably set to 45 ° or less. Therefore, the helix angle is preferably set within the range of 10 ° to 45 °, and more preferably set within the range of 20 ° to 25 °.
　１段目の減速部４１の噛み合い部分（つまり駆動歯車４１３と従動歯車４１５との噛み合い部分）の幅は、１５ｍｍから２０ｍｍの範囲内で設定されている。ここでの幅は、モーター軸５１の軸方向における幅を意味する。１段目の減速部４１の噛み合い部分の幅は、１０ｍｍ以上で設定されることが好ましいが、１５ｍｍ以上で設定されること、または２０ｍｍ以上で設定されることも好ましい。なお、１段目の減速部４１の噛み合い部分の幅は、２５ｍｍ以下で設定されることが好ましい。 The width of the meshing portion of the first-stage reduction gear 41 (that is, the meshing portion between the drive gear 413 and the driven gear 415) is set within the range of 15 mm to 20 mm. The width here means the width of the motor shaft 51 in the axial direction. The width of the meshing portion of the first-stage deceleration unit 41 is preferably set to 10 mm or more, but is also preferably set to 15 mm or more, or 20 mm or more. The width of the meshing portion of the first-stage deceleration portion 41 is preferably set to 25 mm or less.
　１段目の駆動歯車４１３のモジュールは、０．８ｍｍ以上で設定されている。モジュールは、歯車の基準円直径を歯数で割ることで算出される。モジュールが大きいほど、駆動歯車４１３の基準円直径が同一という条件下において、各歯の寸法が大きく設定される。そのため、駆動歯車４１３と従動歯車４１５の歯が折れにくくなり、強度が高められる。 The module of the first stage drive gear 413 is set to 0.8 mm or more. The module is calculated by dividing the reference circle diameter of the gear by the number of teeth. The larger the module, the larger the size of each tooth is set under the condition that the reference circle diameter of the drive gear 413 is the same. Therefore, the teeth of the drive gear 413 and the driven gear 415 are less likely to break, and the strength is increased.
　１段目の駆動歯車４１３の歯数は６以下であり、かつ２以上である。つまり、１段目の駆動歯車４１３の歯数は、６，５，４，３または２であり得る。駆動歯車４１３の歯数が、５以下に設定されること、または４以下に設定されることも好ましい。歯数が小さいほど、駆動歯車４１３の基準円直径が同一という条件下において、各歯の寸法が大きく設定される。そのため、駆動歯車４１３と従動歯車４１５の歯が折れにくくなり、強度が高められる。 The number of teeth of the first stage drive gear 413 is 6 or less and 2 or more. That is, the number of teeth of the first stage drive gear 413 may be 6, 5, 4, 3 or 2. It is also preferable that the number of teeth of the drive gear 413 is set to 5 or less, or 4 or less. The smaller the number of teeth, the larger the size of each tooth is set under the condition that the reference circle diameter of the drive gear 413 is the same. Therefore, the teeth of the drive gear 413 and the driven gear 415 are less likely to break, and the strength is increased.
　１段目の減速部４１の減速比は、例えば６から７の範囲内で設定されている。１段目の減速部４１の減速比は、１０以下で設定されていることが好ましく、更に、９以下に設定されること、８以下に設定されること、７以下に設定されること、または６以下に設定されることも好ましい。１段目の減速部４１の減速比が小さいほど、駆動歯車４１３と従動歯車４１５の一歯あたりの負荷が小さくなる。そのため、駆動歯車４１３と従動歯車４１５の歯が折れにくくなり、強度が高められる。 The reduction ratio of the first-stage reduction unit 41 is set, for example, in the range of 6 to 7. The reduction ratio of the deceleration unit 41 of the first stage is preferably set to 10 or less, further set to 9 or less, set to 8 or less, set to 7 or less, or It is also preferable to set it to 6 or less. The smaller the reduction ratio of the first-stage reduction gear 41, the smaller the load per tooth of the drive gear 413 and the driven gear 415. Therefore, the teeth of the drive gear 413 and the driven gear 415 are less likely to break, and the strength is increased.
　（２段目の減速部）
　２段目の減速部４２は、第１減速軸４５と一体に回転する２段目の駆動歯車４２３と、２段目の駆動歯車４２３に噛み合う２段目の従動歯車４２５とを含む。 (Second stage deceleration section)
The second-stage reduction gear 42 includes a second-stage drive gear 423 that rotates integrally with the first reduction shaft 45, and a second-stage driven gear 425 that meshes with the second-stage drive gear 423.
　２段目の駆動歯車４２３は、金属製の第１減速軸４５の外周面に形成された歯部で、構成されている。２段目の駆動歯車４２３は、第１減速軸４５の一部であり、金属製である。２段目の駆動歯車４２３は、第１減速軸４５に切削加工または塑性加工を施すことによって、形成することが可能である。塑性加工は、例えば、鍛造加工または転造加工である。 The second-stage drive gear 423 is composed of tooth portions formed on the outer peripheral surface of the first metal reduction shaft 45. The second-stage drive gear 423 is a part of the first reduction shaft 45 and is made of metal. The second-stage drive gear 423 can be formed by subjecting the first reduction shaft 45 to cutting or plastic working. The plastic working is, for example, forging or rolling.
　２段目の従動歯車４２５は、２段目の駆動歯車４２３に噛み合うことで、第１減速軸４５の回転駆動力を受けて回転する部材である。２段目の従動歯車４２５の外周面には、２段目の駆動歯車４２３と噛み合う複数の歯が形成されている。 The second-stage driven gear 425 is a member that rotates by receiving the rotational driving force of the first reduction shaft 45 by meshing with the second-stage drive gear 423. A plurality of teeth that mesh with the second-stage drive gear 423 are formed on the outer peripheral surface of the second-stage driven gear 425.
　２段目の従動歯車４２５は、金属を材料として筒状に成形された歯車である。２段目の従動歯車４２５の内周面には、金属製の第２減速軸４７が固定されている。第２減速軸４７の第１端部４７１は、第１分割体９１に配置された軸受４８１に、回転可能に支持されている。第２減速軸４７の第２端部４７２は、第２分割体９２に配置された軸受４８２に、回転可能に支持されている。第１端部４７１と第２端部４７２は、互いに反対側に位置する。軸受４８１と軸受４８２は、ともにリング状の深溝玉軸受である。軸受４８１の内径は、軸受４８２の内径よりも大きく設けられている。 The second-stage driven gear 425 is a gear formed into a cylindrical shape using metal as a material. A second reduction shaft 47 made of metal is fixed to the inner peripheral surface of the second-stage driven gear 425. The first end portion 471 of the second reduction shaft 47 is rotatably supported by a bearing 481 arranged in the first split body 91. The second end portion 472 of the second reduction shaft 47 is rotatably supported by a bearing 482 arranged in the second split body 92. The first end portion 471 and the second end portion 472 are located on opposite sides of each other. Both the bearing 481 and the bearing 482 are ring-shaped deep groove ball bearings. The inner diameter of the bearing 481 is larger than the inner diameter of the bearing 482.
　第１減速軸４５の軸方向において、制御基板３５は、モーター５が有するステーター５３と、１段目の従動歯車４１５及び２段目の減速部４２との間に、位置している。より具体的に述べると、制御基板３５は、ステーター５３のうち２段目の減速部４２（つまり駆動歯車４２３及び従動歯車４２５）に近い側の端部と、１段目の従動歯車４１５のうち２段目の減速部４２（つまり駆動歯車４２３及び従動歯車４２５）に近い側の端部との間に、位置している。ここでのステーター５３の端部は、ステーター５３を構成するティース、巻線、積層コア等の各部材のうち最も外側に位置する部材の端部を、意味する。上記の配置により、モーターユニット３内のスペースが有効活用され、デッドスペースを生じることが抑えられる。その結果、モーターユニット３の小型化が図られる。 In the axial direction of the first deceleration shaft 45, the control board 35 is located between the stator 53 of the motor 5 and the driven gear 415 of the first stage and the deceleration portion 42 of the second stage. More specifically, the control board 35 has an end portion of the stator 53 on the side closer to the second-stage reduction gear 42 (that is, the drive gear 423 and the driven gear 425) and the first-stage driven gear 415. It is located between the end portion on the side close to the second speed reduction portion 42 (that is, the drive gear 423 and the driven gear 425). Here, the end portion of the stator 53 means the end portion of the outermost member among the members such as teeth, windings, and laminated cores constituting the stator 53. With the above arrangement, the space in the motor unit 3 is effectively utilized, and it is possible to suppress the occurrence of dead space. As a result, the size of the motor unit 3 can be reduced.
　（３段目の減速部）
　３段目の減速部４３は、第２減速軸４７と一体に回転する３段目の駆動歯車４３３と、３段目の駆動歯車４３３に噛み合う３段目の従動歯車４３５とを含む。３段目の駆動歯車４３３は、ワンウェイクラッチ４４を介して、第２減速軸４７に連結されている。ワンウェイクラッチ４４は、一方向にのみ回転力を伝達するように構成されたクラッチ機構である。ワンウェイクラッチ４４は、モーター軸５１の回転駆動に伴って回転する方向においては回転力を伝達し、その逆方向においては回転力の伝達を遮断するように構成されている。 (Third stage deceleration part)
The third-stage reduction gear 43 includes a third-stage drive gear 433 that rotates integrally with the second reduction shaft 47, and a third-stage driven gear 435 that meshes with the third-stage drive gear 433. The third-stage drive gear 433 is connected to the second reduction shaft 47 via the one-way clutch 44. The one-way clutch 44 is a clutch mechanism configured to transmit a rotational force in only one direction. The one-way clutch 44 is configured to transmit a rotational force in the direction of rotation accompanying the rotational drive of the motor shaft 51 and to cut off the transmission of the rotational force in the opposite direction.
　３段目の従動歯車４３５は、出力体８のリム８２の外周面に、一体に形成されている。３段目の従動歯車４３５は、３段目の駆動歯車４３３に噛み合うことで、第２減速軸４７の回転駆動力を受けて回転するように構成されている。３段目の従動歯車４３５には、３段目の駆動歯車４３３と噛み合う複数の歯が形成されている。 The third-stage driven gear 435 is integrally formed on the outer peripheral surface of the rim 82 of the output body 8. The driven gear 435 of the third stage is configured to rotate by receiving the rotational driving force of the second reduction shaft 47 by meshing with the drive gear 433 of the third stage. The driven gear 435 of the third stage is formed with a plurality of teeth that mesh with the drive gear 433 of the third stage.
　出力体８では、減速機構４を介して減速して伝達されたモーター５の回転力と、人力によるクランク軸６の回転力とが、合成される。 In the output body 8, the rotational force of the motor 5 decelerated and transmitted via the deceleration mechanism 4 and the rotational force of the crank shaft 6 by human power are combined.
　（モーターユニットの動作）
　一実施形態のモーターユニット３は上記の構成を備えるので、電動自転車１のペダル１８１を運転者が漕ぐことでクランク軸６が回転すると、第１入力体７１及び第２入力体７２は、クランク軸６と一体に回転する。第２入力体７２の回転力が出力体８に伝達されると、出力体８と前側のスプロケット１９１とが回転する。前側のスプロケット１９１が回転すると、チェーン１９３を介して後側のスプロケット１９２が回転し、後輪１１２が回転駆動される。 (Operation of motor unit)
Since the motor unit 3 of one embodiment has the above configuration, when the crank shaft 6 is rotated by the driver pedaling the pedal 181 of the electric bicycle 1, the first input body 71 and the second input body 72 have a crank shaft. It rotates integrally with 6. When the rotational force of the second input body 72 is transmitted to the output body 8, the output body 8 and the front sprocket 191 rotate. When the front sprocket 191 rotates, the rear sprocket 192 rotates via the chain 193, and the rear wheel 112 is rotationally driven.
　また、一実施形態のモーターユニット３では、以下に説明するように、モーター５から出力される回転力を出力体８に加えることが可能である。 Further, in the motor unit 3 of one embodiment, it is possible to apply the rotational force output from the motor 5 to the output body 8 as described below.
　モーター５のモーター軸５１が回転すると、１段目の駆動歯車４１３と従動歯車４１５とが噛み合いながら回転し、これに伴って第１減速軸４５が回転する。第１減速軸４５が回転すると、２段目の駆動歯車４２３と従動歯車４２５とが噛み合いながら回転し、これに伴って第２減速軸４７が回転する。 When the motor shaft 51 of the motor 5 rotates, the first-stage drive gear 413 and the driven gear 415 rotate while meshing with each other, and the first reduction shaft 45 rotates accordingly. When the first reduction gear 45 rotates, the second-stage drive gear 423 and the driven gear 425 rotate while meshing with each other, and the second reduction shaft 47 rotates accordingly.
　第２減速軸４７の回転力は、ワンウェイクラッチ４４を介して３段目の駆動歯車４３３と従動歯車４３５とに伝達され、ひいては出力体８に伝達される。出力体８には、モーター５からの回転力と、運転者がペダル１８１を漕いで発生させる回転力とが、合わさって伝達される。 The rotational force of the second reduction shaft 47 is transmitted to the third-stage drive gear 433 and the driven gear 435 via the one-way clutch 44, and is eventually transmitted to the output body 8. The rotational force from the motor 5 and the rotational force generated by the driver pedaling the pedal 181 are transmitted to the output body 8 in combination.
　一実施形態のモーターユニット３においては、減速機構４が、１段目の減速部４１、第１減速軸４５、２段目の減速部４２、第２減速軸４７、及び３段目の減速部４３を含んだ３段減速の平行軸歯車式の減速機構であり、このうち第２減速軸４７に対してワンウェイクラッチ４４が装着されている。そのため、モーター５を停止した状態で電動自転車１が走行するときに、減速機構４に含まれる多くの部材は、回転することが抑えられる。そのため、運転者は、モーター５を停止して走行する際に、軽い走行感を得ることができる。 In the motor unit 3 of one embodiment, the deceleration mechanism 4 has a first-stage deceleration unit 41, a first-stage deceleration shaft 45, a second-stage deceleration unit 42, a second-stage deceleration shaft 47, and a third-stage deceleration unit. It is a parallel shaft gear type deceleration mechanism for three-stage deceleration including 43, and a one-way clutch 44 is mounted on the second deceleration shaft 47. Therefore, when the electric bicycle 1 travels with the motor 5 stopped, many members included in the deceleration mechanism 4 are suppressed from rotating. Therefore, the driver can obtain a light driving feeling when the motor 5 is stopped and the vehicle travels.
　一実施形態の電動自転車１においては、クランク軸６に掛かっているトルクと、クランク軸６の単位時間当たりの回転数とに応じて、制御基板３５が有する制御部が、モーター５の回転を制御する。クランク軸６に掛かっているトルクは、ユニットケース９に収容された磁歪式のトルク検出器３３で検出される。 In the electric bicycle 1 of one embodiment, the control unit of the control board 35 controls the rotation of the motor 5 according to the torque applied to the crank shaft 6 and the rotation speed of the crank shaft 6 per unit time. do. The torque applied to the crank shaft 6 is detected by the magnetostrictive torque detector 33 housed in the unit case 9.
　トルク検出器３３は磁歪式のものに限定されず、他のセンシング方式のものを採用することも可能である。他のセンシング方式のものとしては、例えば、歪みセンサまたは圧力センサを用いた方式のもの、トーションバーまたはポテンショメータを用いた機械式のものが挙げられる。 The torque detector 33 is not limited to the magnetostrictive type, and it is also possible to adopt another sensing type. Other sensing methods include, for example, a method using a strain sensor or a pressure sensor, and a mechanical type using a torsion bar or a potentiometer.
　クランク軸６の単位時間当たりの回転数は、回転検出器３４で検出される。回転検出器３４は、入力体７と一体に回転する回転体３４１と、回転体３４１から僅かな間隔をあけて位置する光センサ３４２とを備えた、光学式の回転検出器である。 The rotation speed of the crank shaft 6 per unit time is detected by the rotation detector 34. The rotation detector 34 is an optical rotation detector including a rotating body 341 that rotates integrally with the input body 7 and an optical sensor 342 located at a slight distance from the rotating body 341.
　制御基板３５の制御部は、例えばマイクロコンピュータを有し、ＲＯＭ（Ｒｅａｄ　Ｏｎｌｙ　Ｍｅｍｏｒｙ）等の記憶部に記憶されたプログラムを実行することで、各要素の動作を制御する。この制御部としては、公知のものを適宜に利用することができる。 The control unit of the control board 35 has, for example, a microcomputer, and controls the operation of each element by executing a program stored in a storage unit such as a ROM (Read Only Memory). As the control unit, a known one can be appropriately used.
　一実施形態において、減速機構４の全体の減速比は、例えば３０から３５の範囲内で設定されている。減速機構４の全体の減速比は、４０以下で設定されていることが好ましく、更に、３０以下で設定されること、２５以下で設定されること、または２０以下で設定されることも好ましい。減速機構４の全体の減速比が小さいほど、減速機構４に含まれる各歯車の一歯あたりの負荷が小さくなる。そのため、減速機構４に含まれる各歯車の摩耗が低減され、耐久性が向上する。 In one embodiment, the overall reduction ratio of the reduction mechanism 4 is set, for example, in the range of 30 to 35. The overall reduction ratio of the reduction mechanism 4 is preferably set to 40 or less, more preferably 30 or less, 25 or less, or 20 or less. The smaller the overall reduction ratio of the reduction mechanism 4, the smaller the load per tooth of each gear included in the reduction mechanism 4. Therefore, the wear of each gear included in the speed reduction mechanism 4 is reduced, and the durability is improved.
　［変形例］
　次に、一実施形態のモーターユニット３及びこれを備えた電動自転車１の、各種の変形例について説明する。なお、以下に説明する各種の変形例において、既に説明した構成と同様の構成については、同一符号を付して詳しい説明を省略する。 [Modification example]
Next, various modifications of the motor unit 3 of one embodiment and the electric bicycle 1 provided with the motor unit 3 will be described. In the various modifications described below, the same configurations as those already described will be designated by the same reference numerals and detailed description thereof will be omitted.
　図４は、一実施形態のモーターユニット３の第１変形例の断面図である。第１変形例では、減速機構４に組み込まれるワンウェイクラッチ４９の位置が、図３に示すワンウェイクラッチ４４の位置とは相違している。 FIG. 4 is a cross-sectional view of a first modification of the motor unit 3 of the embodiment. In the first modification, the position of the one-way clutch 49 incorporated in the speed reduction mechanism 4 is different from the position of the one-way clutch 44 shown in FIG.
　つまり、一実施形態のモーターユニット３では、モーター５の停止時に減速機構４内での動力伝達を遮断するように機能するワンウェイクラッチ４４が、３段目の駆動歯車４３３と第２減速軸４７との間に介在しているのに対して、第１変形例においては、モーター５の停止時に減速機構４内での動力伝達を遮断するように機能するワンウェイクラッチ４９が、２段目の従動歯車４２５と第２減速軸４７との間に介在している。ワンウェイクラッチ４９は、モーター軸５１の回転駆動に伴って回転する方向においては回転力を伝達し、その逆方向においては回転力の伝達を遮断するように構成されている。 That is, in the motor unit 3 of one embodiment, the one-way clutch 44 that functions to cut off the power transmission in the deceleration mechanism 4 when the motor 5 is stopped is the third-stage drive gear 433 and the second deceleration shaft 47. In the first modification, the one-way clutch 49 that functions to cut off the power transmission in the deceleration mechanism 4 when the motor 5 is stopped is the driven gear of the second stage. It is interposed between the 425 and the second reduction shaft 47. The one-way clutch 49 is configured to transmit a rotational force in the direction of rotation accompanying the rotational drive of the motor shaft 51 and to cut off the transmission of the rotational force in the opposite direction.
　第１変形例においても、減速機構４は、１段目の減速部４１、第１減速軸４５、２段目の減速部４２、第２減速軸４７、及び３段目の減速部４３を含んだ３段減速の平行軸歯車式の減速機構であり、このうち第２減速軸４７に対してワンウェイクラッチ４９が装着されている。そのため、モーター５を停止した状態で電動自転車１が走行するときに、減速機構４に含まれる多くの部材は、回転することが抑えられる。そのため、運転者は、モーター５を停止して走行する際に、軽い走行感を得ることができる。 Also in the first modification, the deceleration mechanism 4 includes the first deceleration section 41, the first deceleration shaft 45, the second deceleration section 42, the second deceleration shaft 47, and the third deceleration section 43. However, it is a parallel shaft gear type deceleration mechanism with three-stage deceleration, of which a one-way clutch 49 is mounted on the second deceleration shaft 47. Therefore, when the electric bicycle 1 travels with the motor 5 stopped, many members included in the deceleration mechanism 4 are suppressed from rotating. Therefore, the driver can obtain a light driving feeling when the motor 5 is stopped and the vehicle travels.
　図５は、一実施形態のモーターユニット３の第２変形例の断面図である。第２変形例では、ユニットケース９のうちモーター５のステーター５３を覆う部分９４が、第１分割体９１及び第２分割体９２とは別体に設けられている。この部分９４は、例えば金属を用いて形成されたカップ状の部材で構成されており、該部材の開口縁部分が、第１分割体９１に固定されている。モーター軸５１の軸方向の中間部分５１５を回転可能に支持する第２軸受５５２と、第１減速軸４５の第１端部４５１を回転可能に支持する軸受４６１とは、第１分割体９１に配置されている。 FIG. 5 is a cross-sectional view of a second modification of the motor unit 3 of the embodiment. In the second modification, the portion 94 of the unit case 9 that covers the stator 53 of the motor 5 is provided separately from the first divided body 91 and the second divided body 92. The portion 94 is composed of, for example, a cup-shaped member formed of metal, and the opening edge portion of the member is fixed to the first divided body 91. The second bearing 552 that rotatably supports the intermediate portion 515 in the axial direction of the motor shaft 51 and the bearing 461 that rotatably supports the first end portion 451 of the first reduction shaft 45 are formed in the first division 91. Have been placed.
　また、第２変形例では、モーター軸５１の軸方向と直交する方向に見たときに、モーター軸５１の中間部分を支持する軸受５５２と、第１減速軸４５の端部を支持する軸受４６１とが、少なくとも一部重なる位置にある。 Further, in the second modification, the bearing 552 that supports the intermediate portion of the motor shaft 51 and the bearing 461 that supports the end portion of the first reduction shaft 45 when viewed in a direction orthogonal to the axial direction of the motor shaft 51. And are at least partially overlapped.
　また、第２変形例では、第２減速軸４７の第１端部４７１を支持するために第１分割体９１に配置された軸受４８１の内径が、第２減速軸４７の第２端部４７２を支持するために第２分割体９２に配置された軸受４８２の内径よりも、小さく設けられている。軸受４８１と軸受４８１の内径は、同一に設けられてもよい。 Further, in the second modification, the inner diameter of the bearing 481 arranged in the first split body 91 for supporting the first end portion 471 of the second reduction shaft 47 is the second end portion 472 of the second reduction shaft 47. It is provided smaller than the inner diameter of the bearing 482 arranged in the second split body 92 to support the bearing. The inner diameters of the bearing 481 and the bearing 481 may be the same.
　また、第２変形例では、制御基板３５と第２分割体９２との間に熱伝導性部材９５が配置されていることに加えて、制御基板３５と第１分割体９１との間に軟質の熱伝導性部材９６が配置されている。第１分割体９１は、内側に突出した形状の放熱部９１５を含んでおり、この放熱部９１５に、板状の熱伝導性部材９６が当たっている。放熱部９１５は、制御基板３５と平行な平板状の形状を有する。放熱部９１５と制御基板３５との間に、熱伝導性部材９６が挟み込まれている。 Further, in the second modification, in addition to the heat conductive member 95 being arranged between the control board 35 and the second divided body 92, the heat conductive member 95 is soft between the control board 35 and the first divided body 91. The heat conductive member 96 of the above is arranged. The first divided body 91 includes a heat radiating portion 915 having a shape protruding inward, and the plate-shaped heat conductive member 96 hits the heat radiating portion 915. The heat radiating unit 915 has a flat plate shape parallel to the control substrate 35. A heat conductive member 96 is sandwiched between the heat radiating portion 915 and the control board 35.
　モーター軸５１の軸方向に見たとき、制御基板３５を挟んだ両側に位置する熱伝導性部材９５，９６と放熱部９２５，９１５とは、ステーター５３の外形の範囲内にある。モーター軸５１の軸方向に見たとき、熱伝導性部材９５の少なくとも一部は、ステーター５３と重なる位置にあり、熱伝導性部材９６の少なくとも一部は、ステーター５３と重なる位置にある。 When viewed in the axial direction of the motor shaft 51, the heat conductive members 95, 96 and the heat radiating portions 925, 915 located on both sides of the control board 35 are within the range of the outer shape of the stator 53. When viewed in the axial direction of the motor shaft 51, at least a part of the heat conductive member 95 is in a position overlapping with the stator 53, and at least a part of the heat conductive member 96 is in a position overlapping with the stator 53.
　図６は、一実施形態のモーターユニット３の第３変形例の断面図である。第３変形例の基本的な構成は第２変形例と共通であるが、第３変形例では、減速機構４に組み込まれるワンウェイクラッチ４９５の位置が、第２変形例のワンウェイクラッチ４４の位置とは相違している。 FIG. 6 is a cross-sectional view of a third modification of the motor unit 3 of the embodiment. The basic configuration of the third modification is the same as that of the second modification, but in the third modification, the position of the one-way clutch 495 incorporated in the deceleration mechanism 4 is the position of the one-way clutch 44 of the second modification. Is different.
　具体的には、モーター５の停止時に減速機構４内の動力伝達を遮断するように機能するワンウェイクラッチ４９５が、出力体８と３段目の従動歯車４３５との間に介在するように、クランク軸６と同軸上に装着されている。ワンウェイクラッチ４９５は、モーター軸５１の回転駆動に伴って回転する方向においては回転力を伝達し、その逆方向においては回転力の伝達を遮断するように構成されている。 Specifically, the crank so that the one-way clutch 495 that functions to cut off the power transmission in the reduction gear mechanism 4 when the motor 5 is stopped is interposed between the output body 8 and the driven gear 435 of the third stage. It is mounted coaxially with the shaft 6. The one-way clutch 495 is configured to transmit a rotational force in the direction of rotation accompanying the rotational drive of the motor shaft 51 and to cut off the transmission of the rotational force in the opposite direction.
　上記の一実施形態や第１－第３変形例において、モーターユニット３は、３段減速の平行軸歯車式の減速機構４を備えているが、減速機構４は３段減速に限定されず、１段減速、２段減速、または４段減速の減速機構であってもよい。いずれの場合であっても、モーター軸と一体に回転する駆動歯車に噛み合うように設けられた従動歯車が、ポリアセタールを用いて形成されていることで、駆動時の騒音が抑制されるという効果と、歯車の摩耗が抑制されるという効果が得られる。 In the above embodiment and the first to third modifications, the motor unit 3 includes a parallel shaft gear type deceleration mechanism 4 for three-stage deceleration, but the deceleration mechanism 4 is not limited to three-stage deceleration. It may be a deceleration mechanism of 1-step deceleration, 2-step deceleration, or 4-step deceleration. In either case, the driven gear provided to mesh with the drive gear that rotates integrally with the motor shaft is formed using polyacetal, which has the effect of suppressing noise during drive. , The effect that the wear of the gear is suppressed can be obtained.
　図７は、一実施形態のモーターユニット３の第４変形例を示す概略的な断面図である。第４変形例において、減速機構４は、第１減速軸４５と、モーター軸５１の回転を第１減速軸４５に減速して伝達する１段目の減速部４１と、第１減速軸４５の回転を出力体８に減速して伝達する２段目の減速部４２とを備える、２段減速の減速機構である。 FIG. 7 is a schematic cross-sectional view showing a fourth modification of the motor unit 3 of one embodiment. In the fourth modification, the deceleration mechanism 4 includes a first deceleration shaft 45, a first-stage deceleration unit 41 that decelerates and transmits the rotation of the motor shaft 51 to the first deceleration shaft 45, and a first deceleration shaft 45. It is a two-stage deceleration deceleration mechanism including a second-stage deceleration unit 42 that decelerates and transmits rotation to the output body 8.
　加えて、第４変形例においては、モーターユニット３が、減速機構４とは別に変速機構３１を備えている。変速機構３１は、クランク軸６と入力体７との間に介在する機構である。変速機構３１は、クランク軸６の回転を増速して、入力体７ひいては出力体８に伝達するように構成されている。変速機構３１は、クランク軸６の回転を増速して伝達する機構に限定されない。変速機構３１が、クランク軸６の回転を減速して入力体７ひいては出力体８に伝達するように構成されてもよい。 In addition, in the fourth modification, the motor unit 3 is provided with a speed change mechanism 31 in addition to the deceleration mechanism 4. The speed change mechanism 31 is a mechanism interposed between the crank shaft 6 and the input body 7. The speed change mechanism 31 is configured to accelerate the rotation of the crank shaft 6 and transmit it to the input body 7 and thus to the output body 8. The speed change mechanism 31 is not limited to a mechanism that accelerates and transmits the rotation of the crank shaft 6. The speed change mechanism 31 may be configured to decelerate the rotation of the crank shaft 6 and transmit it to the input body 7 and thus to the output body 8.
　また、一実施形態及び各種の変形例においては、減速機構４が備える各種の歯車のうち、１段目の従動歯車４１５のみがポリアセタール製であるが、１段目の従動歯車４１５の材料のみならず他の歯車の材料もポリアセタールとすることが可能である。例えば、１段目の従動歯車４１５に加えて２段目の従動歯車４２５をポリアセタールで形成してもよいし、１段目の従動歯車４１５に加えて３段目の従動歯車４３５をポリアセタールで形成してもよいし、１段目の従動歯車４１５に加えて２段目の従動歯車４２５と３段目の従動歯車４３５とをポリアセタールで形成してもよい。 Further, in one embodiment and various modifications, only the first-stage driven gear 415 is made of polyacetal among the various gears provided in the reduction gear mechanism 4, but only the material of the first-stage driven gear 415 is used. The material of other gears can also be polyacetal. For example, the second-stage driven gear 425 may be formed of polyacetal in addition to the first-stage driven gear 415, or the third-stage driven gear 435 may be formed of polyacetal in addition to the first-stage driven gear 415. Alternatively, in addition to the first-stage driven gear 415, the second-stage driven gear 425 and the third-stage driven gear 435 may be formed of polyacetal.
　つまり、一実施形態及び第１－第３変形例のように、減速機構４が３段減速であれば、１段目の従動歯車４１５に加えて、２段目と３段目の従動歯車４２５，４３５の一方または両方をポリアセタールで形成することが可能である。仮に、減速機構４が４段減速であれば、１段目の従動歯車に加えて、２段目から４段目の従動歯車のうち少なくとも一つをポリアセタールで形成することが可能である。第４変形例のように、減速機構４が２段減速であれば、１段目の従動歯車４１５に加えて、２段目の従動歯車４２５をポリアセタールで形成することが可能である。 That is, if the speed reduction mechanism 4 has three-stage deceleration as in the first embodiment and the first to third modifications, the second-stage and third-stage driven gears 425 are added to the first-stage driven gear 415. , 435 can be formed of polyacetal. If the speed reduction mechanism 4 has four-stage deceleration, at least one of the second to fourth-stage driven gears can be formed of polyacetal in addition to the first-stage driven gear. If the speed reduction mechanism 4 has a two-stage deceleration as in the fourth modification, the second-stage driven gear 425 can be formed of polyacetal in addition to the first-stage driven gear 415.
　また、一実施形態及び各種の変形例において、モーターユニット３は、減速機構４を通じて伝達された回転力とクランク軸６の回転力とが、クランク軸６の外周に配置された出力体８で合成される、いわゆる１軸式のモーターユニットであるが、これに限定されず、従来公知の２軸式のモーターユニットであってもよい。２軸式のモーターユニットは、出力体８が、第１出力体と第２出力体とで構成された方式のモーターユニットである。２軸式のモーターユニットにおいては、クランク軸６の回転力は、クランク軸６の外周に配された第１出力体に伝達され、減速機構４を通じて伝達された回転力は、クランク軸６とは離れて位置する第２出力体に伝達される。第１出力体と第２出力体の回転力は、チェーン等の動力伝達用の部材を介して、最終的に合成される。一実施形態及び各種変形例の減速機構４の構成は、１軸式、２軸式のどちらのモーターユニットにおいても採用することが可能である。 Further, in one embodiment and various modifications, in the motor unit 3, the rotational force transmitted through the deceleration mechanism 4 and the rotational force of the crank shaft 6 are combined by the output body 8 arranged on the outer periphery of the crank shaft 6. This is a so-called single-axis motor unit, but the present invention is not limited to this, and a conventionally known two-axis motor unit may be used. The two-axis motor unit is a motor unit in which the output body 8 is composed of a first output body and a second output body. In the two-axis type motor unit, the rotational force of the crank shaft 6 is transmitted to the first output body arranged on the outer periphery of the crank shaft 6, and the rotational force transmitted through the deceleration mechanism 4 is different from the crank shaft 6. It is transmitted to the second output body located at a distance. The rotational forces of the first output body and the second output body are finally combined via a power transmission member such as a chain. The configuration of the deceleration mechanism 4 of one embodiment and various modifications can be adopted in either the one-axis type or the two-axis type motor unit.
　また、一実施形態の電動自転車１は、いわゆる電動アシスト自転車であるが、これに限定されず、モーター５の回転力だけで車輪１１を回転駆動させることのできる電動自転車でもよい。また、一実施形態の電動自転車は、車輪１１を二つ備えているが、車輪１１の数は特に限定されず、例えば車輪１１を三つ備えてもよい。 Further, the electric bicycle 1 of one embodiment is a so-called electrically assisted bicycle, but is not limited to this, and may be an electric bicycle capable of rotationally driving the wheels 11 only by the rotational force of the motor 5. Further, although the electric bicycle of one embodiment includes two wheels 11, the number of wheels 11 is not particularly limited, and for example, three wheels 11 may be provided.
　［態様］
　上記した一実施形態及びこれの各種変形例の説明から明らかなように、第１の態様のモーターユニット（３）は、電動自転車（１）に用いられるモーターユニット（３）であって、人力で駆動されるクランク軸（６）と、モーター軸（５１）を有するモーター（５）と、クランク軸（６）の外周に配され、クランク軸（６）の回転を出力する出力体（８）と、モーター軸（５１）の回転を減速して出力体（８）に伝達する減速機構（４）とを備える。減速機構（４）は、モーター軸（５１）と一体に回転する駆動歯車（４１３）と、駆動歯車（４１３）に噛み合う従動歯車（４１５）とを含む。減速機構（４）のうち少なくとも従動歯車（４１５）の材料は、ポリアセタールである。 [Aspect]
As is clear from the description of the above-described embodiment and various modifications thereof, the motor unit (3) of the first aspect is the motor unit (3) used for the electric bicycle (1), and is manually operated. A driven crank shaft (6), a motor (5) having a motor shaft (51), and an output body (8) arranged on the outer periphery of the crank shaft (6) and outputting the rotation of the crank shaft (6). A deceleration mechanism (4) that decelerates the rotation of the motor shaft (51) and transmits the rotation to the output body (8) is provided. The reduction mechanism (4) includes a drive gear (413) that rotates integrally with the motor shaft (51) and a driven gear (415) that meshes with the drive gear (413). The material of at least the driven gear (415) of the reduction mechanism (4) is polyacetal.
　第１の態様のモーターユニット（３）では、減速機構（４）のなかでも回転数が高い従動歯車（４１５）に着目し、この従動歯車（４１５）をポリアセタールで形成している。ポリアセタールは、樹脂のなかでも高い自己潤滑性を有するので、回転数の高い従動歯車（４１５）の摩耗が抑制され、駆動時の騒音が抑制され、耐久性が高まるという効果が得られる。その結果、第１の態様のモーターユニット（３）によれば、モーターユニット（３）の静音性と耐久性が高められる。 In the motor unit (3) of the first aspect, attention is paid to the driven gear (415) having a high rotation speed among the reduction mechanism (4), and the driven gear (415) is formed of polyacetal. Since polyacetal has the highest self-lubricating property among the resins, the effect of suppressing the wear of the driven gear (415) having a high rotation speed, suppressing the noise during driving, and increasing the durability can be obtained. As a result, according to the motor unit (3) of the first aspect, the quietness and durability of the motor unit (3) are enhanced.
　第２の態様のモーターユニット（３）は、第１の態様との組み合わせにより実現される。第２の態様のモーターユニット（３）では、減速機構（４）は、４段減速の平行軸歯車式の減速機構である。 The motor unit (3) of the second aspect is realized by the combination with the first aspect. In the motor unit (3) of the second aspect, the deceleration mechanism (4) is a four-stage deceleration parallel shaft gear type deceleration mechanism.
　第２の態様のモーターユニット（３）では、減速機構（４）が４段減速であることから、各段の減速比を抑えることができ、減速機構（４）のなかでも回転数の高い１段目の駆動歯車（４１３）と従動歯車（４１５）の一歯あたりの負荷が小さくなり、駆動歯車（４１３）と従動歯車（４１５）の歯が折れにくくなり強度が高められる。 In the motor unit (3) of the second aspect, since the deceleration mechanism (4) has four-stage deceleration, the reduction ratio of each stage can be suppressed, and the rotation speed is higher than that of the deceleration mechanism (4). The load per tooth of the drive gear (413) and the driven gear (415) in the stage is reduced, and the teeth of the drive gear (413) and the driven gear (415) are less likely to break and the strength is increased.
　第３の態様のモーターユニット（３）は、第１の態様との組み合わせにより実現される。第３の態様のモーターユニット（３）では、減速機構（４）は、３段減速の平行軸歯車式の減速機構である。 The motor unit (3) of the third aspect is realized by the combination with the first aspect. In the motor unit (3) of the third aspect, the deceleration mechanism (4) is a parallel shaft gear type deceleration mechanism for three-stage deceleration.
　第３の態様のモーターユニット（３）では、減速機構（４）が３段減速であることから、各段の減速比を抑えることができ、減速機構（４）のなかでも回転数の高い１段目の駆動歯車（４１３）と従動歯車（４１５）の一歯あたりの負荷が小さくなり、駆動歯車（４１３）と従動歯車（４１５）の歯が折れにくくなり強度が高められる。 In the motor unit (3) of the third aspect, since the deceleration mechanism (4) has three-stage deceleration, the reduction ratio of each stage can be suppressed, and the rotation speed is higher than that of the deceleration mechanism (4). The load per tooth of the drive gear (413) and the driven gear (415) in the stage is reduced, and the teeth of the drive gear (413) and the driven gear (415) are less likely to break and the strength is increased.
　第４の態様のモーターユニット（３）は、第１の態様との組み合わせにより実現される。第４の態様のモーターユニット（３）では、減速機構（４）は、２段減速の平行軸歯車式の減速機構である。 The motor unit (3) of the fourth aspect is realized by the combination with the first aspect. In the motor unit (3) of the fourth aspect, the deceleration mechanism (4) is a two-stage deceleration parallel shaft gear type deceleration mechanism.
　第４の態様のモーターユニット（３）では、減速機構（４）が２段減速であることから、各段の減速比を抑えることができ、減速機構（４）のなかでも回転数の高い１段目の駆動歯車（４１３）と従動歯車（４１５）の一歯あたりの負荷が小さくなり、駆動歯車（４１３）と従動歯車（４１５）の歯が折れにくくなり強度が高められる。 In the motor unit (3) of the fourth aspect, since the deceleration mechanism (4) has two-stage deceleration, the reduction ratio of each stage can be suppressed, and the rotation speed is higher than that of the deceleration mechanism (4). The load per tooth of the drive gear (413) and the driven gear (415) in the stage is reduced, and the teeth of the drive gear (413) and the driven gear (415) are less likely to break and the strength is increased.
　第５の態様のモーターユニット（３）は、第１の態様との組み合わせにより実現される。第５の態様のモーターユニット（３）では、減速機構（４）は、１段減速の平行軸歯車式の減速機構である。 The motor unit (3) of the fifth aspect is realized by the combination with the first aspect. In the motor unit (3) of the fifth aspect, the deceleration mechanism (4) is a parallel shaft gear type deceleration mechanism for one-step deceleration.
　第５の態様のモーターユニット（３）では、減速機構（４）が１段減速であることから、機構がコンパクト化及び軽量化され、しかも、従動歯車（４１５）はポリアセタール製であることから、駆動歯車（４１３）と従動歯車（４１５）の摩耗が抑制され、駆動時の騒音が抑制され、耐久性が高められる。 In the motor unit (3) of the fifth aspect, since the deceleration mechanism (4) is one-step deceleration, the mechanism is made compact and lightweight, and the driven gear (415) is made of polyacetal. Wear of the drive gear (413) and the driven gear (415) is suppressed, noise during driving is suppressed, and durability is enhanced.
　第６の態様のモーターユニット（３）は、第１から第４のいずれか一つの態様との組み合わせにより実現される。第６の態様のモーターユニット（３）は、制御基板（３５）を更に備える。減速機構（４）は、従動歯車（４１５）と一体に回転する第１減速軸（４５）と、第１減速軸（４５）と一体に回転する２段目の駆動歯車（４２３）と、を更に含む。モーター（５）は、ステーター（５３）を更に有する。第１減速軸（４５）の軸方向において、ステーター（５３）のうち２段目の駆動歯車（４２３）に近い側の端部と、従動歯車（４１５）のうち２段目の駆動歯車（４２３）に近い側の端部との間に、制御基板（３５）が位置する。 The motor unit (3) of the sixth aspect is realized by the combination with any one of the first to the fourth aspects. The motor unit (3) of the sixth aspect further includes a control board (35). The reduction gear (4) has a first reduction shaft (45) that rotates integrally with the driven gear (415) and a second-stage drive gear (423) that rotates integrally with the first reduction shaft (45). Further included. The motor (5) further has a stator (53). In the axial direction of the first reduction gear (45), the end of the stator (53) on the side closer to the second stage drive gear (423) and the second stage drive gear (423) of the driven gear (415). ), The control board (35) is located between the end and the end.
　第６の態様のモーターユニット（３）では、ユニット内のスペースを有効活用し、デッドスペースが生じることを抑えることができる。そのため、モーターユニット（３）の小型化が図られる。 In the motor unit (3) of the sixth aspect, the space in the unit can be effectively utilized and the occurrence of dead space can be suppressed. Therefore, the size of the motor unit (3) can be reduced.
　第７の態様のモーターユニット（３）は、第１から第４のいずれか一つの態様との組み合わせにより実現される。第７の態様のモーターユニット（３）では、減速機構（４）は、従動歯車（４１５）と一体に回転する第１減速軸（４５）と、第１減速軸（４５）と一体に回転する２段目の駆動歯車（４２３）と、２段目の駆動歯車（４２３）に噛み合う２段目の従動歯車（４２５）と、２段目の従動歯車（４２５）と一体に回転する第２減速軸（４７）と、第２減速軸（４７）に装着されたワンウェイクラッチ（４４，４９）とを更に含む。 The motor unit (3) of the seventh aspect is realized by the combination with any one of the first to the fourth aspects. In the motor unit (3) of the seventh aspect, the deceleration mechanism (4) rotates integrally with the first deceleration shaft (45) that rotates integrally with the driven gear (415) and the first deceleration shaft (45). The second deceleration that rotates integrally with the second-stage drive gear (423), the second-stage driven gear (425) that meshes with the second-stage drive gear (423), and the second-stage driven gear (425). Further includes a shaft (47) and a one-way clutch (44, 49) mounted on the second reduction shaft (47).
　第７の態様のモーターユニット（３）では、ワンウェイクラッチ（４４，４９）が、第１減速軸（４５）ではなく第２減速軸（４７）に装着されているので、運転者は、モーター（５）を停止して走行する際に、軽い走行感を得ることができる。 In the motor unit (3) of the seventh aspect, since the one-way clutch (44, 49) is mounted on the second reduction shaft (47) instead of the first reduction shaft (45), the driver can use the motor ( When the vehicle is stopped and the vehicle is driven, a light driving feeling can be obtained.
　第８の態様のモーターユニット（３）は、第１から第７のいずれか一つの態様との組み合わせにより実現される。第８の態様のモーターユニット（３）は、クランク軸（６）の回転を減速または増速して出力体（８）に伝達する変速機構（３１）を、更に備える。 The motor unit (3) of the eighth aspect is realized by the combination with any one of the first to seventh aspects. The motor unit (3) of the eighth aspect further includes a speed change mechanism (31) that decelerates or accelerates the rotation of the crank shaft (6) and transmits the rotation to the output body (8).
　第８の態様のモーターユニット（３）では、人力によるクランク軸（６）の回転を、変速させて出力体（８）に伝えることができる。 In the motor unit (3) of the eighth aspect, the rotation of the crank shaft (6) by human power can be changed and transmitted to the output body (8).
　第９の態様のモーターユニット（３）は、第１から第８のいずれか一つの態様との組み合わせにより実現される。第９の態様のモーターユニット（３）では、減速機構（４）の減速比は、４０以下である。 The motor unit (3) of the ninth aspect is realized by the combination with any one of the first to eighth aspects. In the motor unit (3) of the ninth aspect, the reduction ratio of the reduction mechanism (4) is 40 or less.
　第９の態様のモーターユニット（３）では、４０以下の減速比を有するモーターユニット（３）において、静音性と耐久性が高められる。 In the motor unit (3) of the ninth aspect, the quietness and durability are enhanced in the motor unit (3) having a reduction ratio of 40 or less.
　第１０の態様のモーターユニット（３）は、第１から第９のいずれか一つの態様との組み合わせにより実現される。第１０の態様のモーターユニット（３）は、モーター軸（５１）を支持する第１軸受（５５１）及び第２軸受（５５２）を、更に備える。第２軸受（５５２）と駆動歯車（４１３）との距離は、第１軸受（５５１）と駆動歯車（４１３）との距離よりも近い。第２軸受（５５２）の内径は、第１軸受（５５１）の内径よりも大きい。 The motor unit (3) of the tenth aspect is realized by the combination with any one of the first to ninth aspects. The motor unit (3) of the tenth aspect further includes a first bearing (551) and a second bearing (552) that support the motor shaft (51). The distance between the second bearing (552) and the drive gear (413) is closer than the distance between the first bearing (551) and the drive gear (413). The inner diameter of the second bearing (552) is larger than the inner diameter of the first bearing (551).
　第１０の態様のモーターユニット（３）では、回転数の高いモーター軸（５１）を支持する構成全体の剛性が高まる。そのため、駆動歯車（４１３）と従動歯車（４１５）との噛み合いの精度が高まる。 In the motor unit (3) of the tenth aspect, the rigidity of the entire configuration that supports the motor shaft (51) having a high rotation speed is increased. Therefore, the accuracy of meshing between the drive gear (413) and the driven gear (415) is improved.
　第１１の態様のモーターユニット（３）は、第１から第１０のいずれか一つの態様との組み合わせにより実現される。第１１の態様のモーターユニット（３）では、駆動歯車（４１３）は、モーター軸（５１）の一部を塑性加工して形成したものである。 The motor unit (3) of the eleventh aspect is realized by the combination with any one of the first to tenth aspects. In the motor unit (3) of the eleventh aspect, the drive gear (413) is formed by plastic working a part of the motor shaft (51).
　第１１の態様のモーターユニット（３）では、駆動歯車（４１３）において良好な面粗さが得られる。そのため、駆動歯車（４１３）と従動歯車（４１５）との間の摩擦抵抗が低減され、駆動時の騒音が抑制され、従動歯車（４１５）の摩耗が抑制される。 In the motor unit (3) of the eleventh aspect, good surface roughness can be obtained in the drive gear (413). Therefore, the frictional resistance between the driving gear (413) and the driven gear (415) is reduced, noise during driving is suppressed, and wear of the driven gear (415) is suppressed.
　第１２の態様のモーターユニット（３）は、第１から第１１のいずれか一つの態様との組み合わせにより実現される。第１２の態様のモーターユニット（３）では、駆動歯車（４１３）は、ショットピーニング、エアブラストまたはコーティングが施されたものである。 The motor unit (3) of the twelfth aspect is realized by the combination with any one of the first to eleventh aspects. In the motor unit (3) of the twelfth aspect, the drive gear (413) is shot peened, air blasted or coated.
　第１２の態様のモーターユニット（３）では、駆動歯車（４１３）の表面の面粗さが良化し、駆動歯車（４１３）の表面の滑り性が高まる。そのため、駆動歯車（４１３）と従動歯車（４１５）との間の摩擦抵抗が低減され、駆動時の騒音が抑制されるという効果と、従動歯車（４１５）の摩耗が抑制されるという効果が得られる。また、第１２の態様のモーターユニット（３）では、駆動歯車（４１３）の耐摩耗性が向上する効果と、放熱性が向上する効果が得られる。 In the motor unit (3) of the twelfth aspect, the surface roughness of the surface of the drive gear (413) is improved, and the slipperiness of the surface of the drive gear (413) is enhanced. Therefore, the frictional resistance between the drive gear (413) and the driven gear (415) is reduced, the noise during driving is suppressed, and the wear of the driven gear (415) is suppressed. Be done. Further, in the motor unit (3) of the twelfth aspect, the effect of improving the wear resistance of the drive gear (413) and the effect of improving the heat dissipation can be obtained.
　第１３の態様のモーターユニット（３）は、第１から第１２のいずれか一つの態様との組み合わせにより実現される。第１３の態様のモーターユニット（３）では、駆動歯車（４１３）と従動歯車（４１５）は、互いに噛み合う斜歯歯車である。 The motor unit (3) of the thirteenth aspect is realized by the combination with any one of the first to the twelfth aspects. In the motor unit (3) of the thirteenth aspect, the drive gear (413) and the driven gear (415) are oblique gears that mesh with each other.
　第１３の態様のモーターユニット（３）では、駆動歯車（４１３）と従動歯車（４１５）の噛み合い率が高められる。加えて、従動歯車（４１５）の材料は、比較的に耐熱性が低い性質を有するポリアセタールであるが、従動歯車（４１５）の回転中に周囲の空気をかき混ぜやすくなるため、従動歯車（４１５）の放熱性が高められる。 In the motor unit (3) of the thirteenth aspect, the meshing ratio of the drive gear (413) and the driven gear (415) is increased. In addition, the material of the driven gear (415) is polyacetal having a property of relatively low heat resistance, but since it becomes easy to stir the surrounding air during the rotation of the driven gear (415), the driven gear (415) The heat dissipation of is enhanced.
　第１４の態様のモーターユニット（３）は、第１３の態様との組み合わせにより実現される。第１４の態様のモーターユニット（３）では、駆動歯車（４１３）と従動歯車（４１５）は、１０°から４５°の範囲内のねじれ角を有する斜歯歯車である。 The motor unit (3) of the fourteenth aspect is realized by the combination with the thirteenth aspect. In the motor unit (3) of the fourteenth aspect, the drive gear (413) and the driven gear (415) are oblique gears having a helix angle in the range of 10 ° to 45 °.
　第１４の態様のモーターユニット（３）では、駆動歯車（４１３）と従動歯車（４１５）の噛み合い率が高められることに加えて、ねじれ角が大きすぎて従動歯車（４１５）が倒れることは抑えられる。 In the motor unit (3) of the fourteenth aspect, in addition to increasing the meshing ratio between the drive gear (413) and the driven gear (415), it is possible to prevent the driven gear (415) from collapsing due to an excessively large helix angle. Be done.
　第１５の態様のモーターユニット（３）は、第１から第１４のいずれか一つの態様との組み合わせにより実現される。第１５の態様のモーターユニット（３）では、駆動歯車（４１３）と従動歯車（４１５）の噛み合い部分の幅は、１０ｍｍ以上に設定されている。 The motor unit (3) of the fifteenth aspect is realized by the combination with any one of the first to the fourteenth aspects. In the motor unit (3) of the fifteenth aspect, the width of the meshing portion between the drive gear (413) and the driven gear (415) is set to 10 mm or more.
　第１５の態様のモーターユニット（３）では、駆動歯車（４１３）と従動歯車（４１５）の噛み合いを確保し、静音性と耐久性を高めることができる。 In the motor unit (3) of the fifteenth aspect, the meshing of the drive gear (413) and the driven gear (415) can be ensured, and quietness and durability can be improved.
　第１６の態様のモーターユニット（３）は、第１から第１５のいずれか一つの態様との組み合わせにより実現される。第１６の態様のモーターユニット（３）では、駆動歯車（４１３）のモジュールは、０．８ｍｍ以上である。 The motor unit (3) of the sixteenth aspect is realized by the combination with any one of the first to fifteenth aspects. In the motor unit (3) of the sixteenth aspect, the module of the drive gear (413) is 0.8 mm or more.
　第１６の態様のモーターユニット（３）では、駆動歯車（４１３）の各歯の寸法が確保されるので、駆動歯車（４１３）の歯が折れにくくなり強度が高められる。 In the motor unit (3) of the 16th aspect, since the dimensions of each tooth of the drive gear (413) are secured, the teeth of the drive gear (413) are less likely to break and the strength is increased.
　第１７の態様のモーターユニット（３）は、第１から第１６のいずれか一つの態様との組み合わせにより実現される。第１７の態様のモーターユニット（３）では、駆動歯車（４１３）と従動歯車（４１５）で構成される減速部（４１）の減速比は、１０以下である。 The motor unit (3) of the 17th aspect is realized by the combination with any one of the 1st to 16th aspects. In the motor unit (3) of the seventeenth aspect, the reduction ratio of the reduction unit (41) composed of the drive gear (413) and the driven gear (415) is 10 or less.
　第１７の態様のモーターユニット（３）では、減速部（４１）の一歯あたりの負荷が抑えられるので、歯が折れにくくなり強度が高められる。 In the motor unit (3) of the 17th aspect, since the load per tooth of the deceleration part (41) is suppressed, the teeth are less likely to break and the strength is increased.
　第１８の態様のモーターユニット（３）は、第１から第１７のいずれか一つの態様との組み合わせにより実現される。第１８の態様のモーターユニット（３）では、駆動歯車（４１３）の歯数は、２以上であり、かつ６以下である。 The motor unit (3) of the eighteenth aspect is realized by the combination with any one of the first to the seventeenth aspects. In the motor unit (3) of the eighteenth aspect, the number of teeth of the drive gear (413) is 2 or more and 6 or less.
　第１８の態様のモーターユニット（３）では、駆動歯車（４１３）の歯数と、これに噛み合う樹脂製の従動歯車（４１５）の歯数も抑えることができる。そのため、回転数が高い駆動歯車（４１３）と従動歯車（４１５）において歯が折れにくくなり、耐久性が更に高められる。 In the motor unit (3) of the eighteenth aspect, the number of teeth of the drive gear (413) and the number of teeth of the resin driven gear (415) that meshes with the drive gear (413) can also be suppressed. Therefore, in the drive gear (413) and the driven gear (415) having a high rotation speed, the teeth are less likely to break, and the durability is further improved.
　第１９の態様のモーターユニット（３）は、第１８の態様との組み合わせにより実現される。第１９の態様のモーターユニット（３）では、駆動歯車（４１３）の歯数は、４以下である。 The motor unit (3) of the 19th aspect is realized by the combination with the 18th aspect. In the motor unit (3) of the nineteenth aspect, the number of teeth of the drive gear (413) is 4 or less.
　第１９の態様のモーターユニット（３）では、駆動歯車（４１３）の歯数と、これに噛み合う樹脂製の従動歯車（４１５）の歯数を更に抑え、耐久性を高めることができる。 In the motor unit (3) of the nineteenth aspect, the number of teeth of the drive gear (413) and the number of teeth of the resin driven gear (415) that meshes with the number of teeth can be further suppressed, and the durability can be improved.
　第２０の態様のモーターユニット（３）は、第１から第１９のいずれか一つの態様との組み合わせにより実現される。第２０の態様のモーターユニット（３）では、出力体（８）は、減速機構（４）を通じて伝達された回転力とクランク軸（６）の回転力とが合成される部材である。 The motor unit (3) of the twentieth aspect is realized by a combination with any one of the first to nineteenth aspects. In the motor unit (3) of the twentieth aspect, the output body (8) is a member in which the rotational force transmitted through the deceleration mechanism (4) and the rotational force of the crank shaft (6) are combined.
　第２０の態様のモーターユニット（３）では、いわゆる１軸式のモーターユニット（３）において、静音性と耐久性が高められる。 In the motor unit (3) of the twentieth aspect, the quietness and durability are enhanced in the so-called one-axis type motor unit (3).
　第１の態様の電動自転車（１）は、第１から第２０のいずれか一つの態様のモーターユニット（３）と、モーターユニット（３）のモーター（５）の回転力が伝えられる車輪（１１）とを具備する。 The electric bicycle (1) of the first aspect is a wheel (11) to which the rotational force of the motor unit (3) of any one of the first to the twentieth aspects and the motor (5) of the motor unit (3) is transmitted. ) And.
　第１の態様の電動自転車（１）では、モーターユニット（３）において静音性と耐久性が高められる。 In the electric bicycle (1) of the first aspect, the quietness and durability of the motor unit (3) are enhanced.

Claims (21)

  1. 　電動自転車に用いられるモーターユニットであって、
    　人力で駆動されるクランク軸と、
    　モーター軸を有するモーターと、
    　前記クランク軸の回転を出力する出力体と、
    　前記モーター軸の回転を減速して前記出力体に伝達する減速機構と、を備え、
    　前記減速機構は、
    　前記モーター軸と一体に回転する駆動歯車と、
    　前記駆動歯車に噛み合う従動歯車と、を含み、
    　前記減速機構のうち少なくとも前記従動歯車の材料は、ポリアセタールである
    　モーターユニット。     A motor unit used for electric bicycles
    A crank shaft driven by human power and
    A motor with a motor shaft and
    An output body that outputs the rotation of the crank shaft and
    A deceleration mechanism that decelerates the rotation of the motor shaft and transmits it to the output body is provided.
    The deceleration mechanism
    A drive gear that rotates integrally with the motor shaft,
    Including a driven gear that meshes with the drive gear,
    Of the reduction mechanism, at least the material of the driven gear is a motor unit made of polyacetal.
  2. 　前記減速機構は、４段減速の平行軸歯車式の減速機構である
    　請求項１のモーターユニット。     The motor unit according to claim 1, wherein the deceleration mechanism is a parallel shaft gear type deceleration mechanism for 4-step deceleration.
  3. 　前記減速機構は、３段減速の平行軸歯車式の減速機構である
    　請求項１のモーターユニット。     The motor unit according to claim 1, wherein the deceleration mechanism is a parallel shaft gear type deceleration mechanism for three-stage deceleration.
  4. 　前記減速機構は、２段減速の平行軸歯車式の減速機構である
    　請求項１のモーターユニット。     The motor unit according to claim 1, wherein the deceleration mechanism is a parallel shaft gear type deceleration mechanism for two-stage deceleration.
  5. 　前記減速機構は、１段減速の平行軸歯車式の減速機構である
    　請求項１のモーターユニット。     The motor unit according to claim 1, wherein the deceleration mechanism is a parallel shaft gear type deceleration mechanism for one-stage deceleration.
  6. 　制御基板を更に備え、
    　前記減速機構は、前記従動歯車と一体に回転する第１減速軸と、前記第１減速軸と一体に回転する２段目の駆動歯車と、を更に含み、
    　前記モーターは、ステーターを更に有し、
    　前記第１減速軸の軸方向において、前記ステーターのうち前記２段目の駆動歯車に近い側の端部と、前記従動歯車のうち前記２段目の駆動歯車に近い側の端部との間に、前記制御基板が位置する
    　請求項１から４のいずれか一項のモーターユニット。     Further equipped with a control board,
    The deceleration mechanism further includes a first deceleration shaft that rotates integrally with the driven gear, and a second-stage drive gear that rotates integrally with the first deceleration shaft.
    The motor further has a stator and
    In the axial direction of the first reduction gear, between the end of the stator on the side closer to the second stage drive gear and the end of the driven gear on the side closer to the second stage drive gear. The motor unit according to any one of claims 1 to 4, wherein the control board is located.
  7. 　前記減速機構は、
    　前記従動歯車と一体に回転する第１減速軸と、
    　前記第１減速軸と一体に回転する２段目の駆動歯車と、
    　前記２段目の駆動歯車に噛み合う２段目の従動歯車と、
    　前記２段目の従動歯車と一体に回転する第２減速軸と、
    　前記第２減速軸に装着されたワンウェイクラッチと、を更に含む
    　請求項１から４のいずれか一項のモーターユニット。     The deceleration mechanism
    A first reduction shaft that rotates integrally with the driven gear,
    A second-stage drive gear that rotates integrally with the first reduction shaft,
    The second-stage driven gear that meshes with the second-stage drive gear,
    A second reduction shaft that rotates integrally with the second-stage driven gear,
    The motor unit according to any one of claims 1 to 4, further comprising a one-way clutch mounted on the second reduction shaft.
  8. 　前記クランク軸の回転を減速または増速して前記出力体に伝達する変速機構を、更に備える
    　請求項１から７のいずれか一項のモーターユニット。     The motor unit according to any one of claims 1 to 7, further comprising a speed change mechanism for decelerating or increasing the rotation of the crank shaft and transmitting the speed to the output body.
  9. 　前記減速機構の減速比は、４０以下である
    　請求項１から８のいずれか一項のモーターユニット。     The motor unit according to any one of claims 1 to 8, wherein the reduction ratio of the reduction mechanism is 40 or less.
  10. 　前記モーター軸を支持する第１軸受及び第２軸受を、更に備え、
    　前記第２軸受と前記駆動歯車との距離は、前記第１軸受と前記駆動歯車との距離よりも近く、
    　前記第２軸受の内径は、前記第１軸受の内径よりも大きい
    　請求項１から９のいずれか一項のモーターユニット。     A first bearing and a second bearing that support the motor shaft are further provided.
    The distance between the second bearing and the drive gear is closer than the distance between the first bearing and the drive gear.
    The motor unit according to any one of claims 1 to 9, wherein the inner diameter of the second bearing is larger than the inner diameter of the first bearing.
  11. 　前記駆動歯車は、前記モーター軸の一部を塑性加工して形成したものである
    　請求項１から１０のいずれか一項のモーターユニット。     The motor unit according to any one of claims 1 to 10, wherein the drive gear is formed by plastic working a part of the motor shaft.
  12. 　前記駆動歯車は、ショットピーニング、エアブラストまたはコーティングが施されたものである
    　請求項１から１１のいずれか一項のモーターユニット。     The motor unit according to any one of claims 1 to 11, wherein the drive gear is shot peening, air blasted or coated.
  13. 　前記駆動歯車と前記従動歯車は、互いに噛み合う斜歯歯車である
    　請求項１から１２のいずれか一項のモーターユニット。     The motor unit according to any one of claims 1 to 12, wherein the drive gear and the driven gear are oblique tooth gears that mesh with each other.
  14. 　前記駆動歯車と前記従動歯車は、１０°から４５°の範囲内のねじれ角を有する斜歯歯車である
    　請求項１３のモーターユニット。     The motor unit according to claim 13, wherein the drive gear and the driven gear are diagonal gears having a helix angle in the range of 10 ° to 45 °.
  15. 　前記駆動歯車と前記従動歯車の噛み合い部分の幅は、１０ｍｍ以上に設定されている
    　請求項１から１４のいずれか一項のモーターユニット。     The motor unit according to any one of claims 1 to 14, wherein the width of the meshing portion between the drive gear and the driven gear is set to 10 mm or more.
  16. 　前記駆動歯車のモジュールは、０．８ｍｍ以上である
    　請求項１から１５のいずれか一項のモーターユニット。     The motor unit according to any one of claims 1 to 15, wherein the drive gear module is 0.8 mm or more.
  17. 　前記駆動歯車と前記従動歯車で構成される減速部の減速比は、１０以下である
    　請求項１から１６のいずれか一項のモーターユニット。     The motor unit according to any one of claims 1 to 16, wherein the reduction ratio of the reduction unit composed of the drive gear and the driven gear is 10 or less.
  18. 　前記駆動歯車の歯数は、２以上であり、かつ６以下である
    　請求項１から１７のいずれか一項のモーターユニット。     The motor unit according to any one of claims 1 to 17, wherein the number of teeth of the drive gear is 2 or more and 6 or less.
  19. 　前記駆動歯車の歯数は、４以下である
    　請求項１８のモーターユニット。     The motor unit according to claim 18, wherein the number of teeth of the drive gear is 4 or less.
  20. 　前記出力体は、前記減速機構を通じて伝達された回転力と前記クランク軸の回転力とが合成される部材である
    　請求項１から１９のいずれか一項のモーターユニット。     The motor unit according to any one of claims 1 to 19, wherein the output body is a member in which the rotational force transmitted through the deceleration mechanism and the rotational force of the crank shaft are combined.
  21. 　請求項１から２０のいずれか一項に記載のモーターユニットと、
    　前記モーターユニットの前記モーターの回転力が伝えられる車輪と、を具備する
    　電動自転車。     The motor unit according to any one of claims 1 to 20 and the motor unit.
    An electric bicycle including a wheel to which the rotational force of the motor of the motor unit is transmitted.
PCT/JP2021/021133 2020-06-04 2021-06-03 Motor unit and electric automobile WO2021246473A1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2024094148A (en) 2022-12-27 2024-07-09 株式会社シマノ Drive unit for human-powered vehicles

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0931688A (en) * 1995-07-20 1997-02-04 Kobe Steel Ltd Gear made of al alloy excellent in durability
JPH10316081A (en) * 1997-01-29 1998-12-02 Nippon Seiko Kk Driving force auxiliary device for bicycle
JP2005219728A (en) * 2004-01-06 2005-08-18 Land Walker Ltd Bicycle and differential gear for bicycle
JP2007176221A (en) * 2005-12-27 2007-07-12 Matsushita Electric Ind Co Ltd Motor unit and electric bicycle using the same
JP2016193628A (en) * 2015-03-31 2016-11-17 株式会社シマノ Drive unit for bicycle, and bicycle equipped with the same
JP2019156185A (en) * 2018-03-13 2019-09-19 パナソニックＩｐマネジメント株式会社 Motor unit and electric bicycle

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9718514B2 (en) 2012-07-11 2017-08-01 Panasonic Intellectual Property Management Co., Ltd. Electrically assisted bicycle

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0931688A (en) * 1995-07-20 1997-02-04 Kobe Steel Ltd Gear made of al alloy excellent in durability
JPH10316081A (en) * 1997-01-29 1998-12-02 Nippon Seiko Kk Driving force auxiliary device for bicycle
JP2005219728A (en) * 2004-01-06 2005-08-18 Land Walker Ltd Bicycle and differential gear for bicycle
JP2007176221A (en) * 2005-12-27 2007-07-12 Matsushita Electric Ind Co Ltd Motor unit and electric bicycle using the same
JP2016193628A (en) * 2015-03-31 2016-11-17 株式会社シマノ Drive unit for bicycle, and bicycle equipped with the same
JP2019156185A (en) * 2018-03-13 2019-09-19 パナソニックＩｐマネジメント株式会社 Motor unit and electric bicycle

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