DRIVE UNIT AND ELECTRIC VEHICLE

Abstract

A drive unit (20) used for an electric vehicle comprises: a motor (40) having a rotor (42) with an opening portion at a rotation center; a housing (31) accommodating the motor (40); a crankshaft (30) rotatably mounted on the housing (31); a gear that outputs a rotational force of the motor (40); and a power transmission mechanism (50) that decelerates or accelerates the rotational force of the motor (40) to transmit the power to the gear, wherein the power transmission mechanism (50) has at least one gear provided with tooth portions on one surface, wherein the rotor (42) and the tooth portions are arranged at positions that overlap in an axial direction of the crankshaft (30), and wherein at least a part of the gear is arranged within the opening portion.

Description

TECHNICAL FIELD

[0001] The present invention relates to a drive unit and an electric vehicle having the drive unit. BACKGROUND

[0002] From the prior art, a drive unit for use in an electric vehicle is known, which comprises a motor and a power transmission mechanism for transmitting rotational power of the motor to a gear or sprocket (see, for example, JP 7246001 B). REPRESENTATION TECHNICAL PROBLEM

[0003] In recent years, there has been a demand for reducing the size of drive units. In JP 7246001 B, a motor contained in the drive unit and a circuit board connected to the motor are arranged close to each other to reduce the size of a drive unit. Meanwhile, the prior art, including JP 7246001 B, leaves room for improvement in reducing the size of the drive unit. SOLUTION TO THE PROBLEM

[0004] A drive unit according to one aspect of the present invention is a drive unit for use in an electric vehicle, comprising: a motor having a rotor with an opening portion at a rotation center, a housing that houses the motor; a crankshaft rotatably mounted on the housing; a gear that outputs a rotational force of the motor; and a power transmission mechanism that decelerates or accelerates the rotational force of the motor to transmit it to the gear, the power transmission mechanism comprising at least one gear provided with tooth portions on one surface, the rotor and the tooth portions being arranged at positions overlapping in an axial direction of the crankshaft, and at least a part of the gear is disposed inside the crankshaft.is arranged inside the opening section.

[0005] A drive unit of one aspect of the present invention is a drive unit for use in an electric vehicle, comprising: a motor having a rotor with an opening portion at a rotation center; a housing that houses the motor; a crankshaft rotatably mounted on the housing and driven by a human power drive; a first gear that outputs a rotational force of the motor; a second gear that outputs a rotational force of the human power drive; and a power transmission mechanism that decelerates or accelerates the rotational force of the motor to transmit it to the first gear, the power transmission mechanism comprising at least one gear.A gear wheel provided with tooth portions on one surface, wherein the rotor and the tooth portions are arranged at positions overlapping in an axial direction of the crankshaft, and wherein at least a part of the gear wheel or gear wheel is arranged inside or within the opening portion.

[0006] A drive unit of one aspect of the present invention is a drive unit for use in an electric vehicle, comprising: a motor having a rotor with an opening portion at a rotation center; a housing; a crankshaft rotatably mounted on the housing; a gear that outputs a rotational force of the motor; and a power transmission mechanism that decelerates or accelerates the rotational force of the motor to transmit it to the gear, wherein the power transmission mechanism includes at least one gear provided with tooth portions on one surface, wherein the rotor and the tooth portions are arranged at positions overlapping in an axial direction of the crankshaft, and wherein a rotational axis of the rotor and a rotational axis of the crankshaft are concentrically arranged.

[0007] A drive unit of one aspect of the present invention is a drive unit for use in an electric vehicle, comprising: a motor; a housing that houses the motor; a crankshaft rotatably mounted on the housing; a gear or sprocket that outputs a rotational force of the motor; and a power transmission mechanism that decelerates or accelerates the rotational force of the motor to transmit it to the gear or sprocket; and a rotation detecting section that detects rotation of the crankshaft or a member rotating integrally with the crankshaft, the rotation detecting section rotating integrally with the crankshaft.

[0008] A drive unit of one aspect of the present invention is a drive unit for use in an electric vehicle, comprising: a motor; a housing that houses the motor; a crankshaft rotatably mounted on the housing; a gear that outputs a rotational power of the motor; and a power transmission mechanism that decelerates or accelerates the rotational power of the motor to transmit it to the gear, the motor comprising: a motor shaft that is an output shaft; a stator fixed to the housing; and a rotor fixed to the motor shaft and having a magnet, the rotor being arranged to face the stator in a direction along a rotational axis of the motor shaft, the power transmission mechanism comprising at least one gear.A transmission gear provided with tooth portions on one surface, and wherein the stator and the tooth portions are arranged at positions overlapping in an axial direction of the crankshaft. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0009] The drive unit according to the present invention can be reduced in size. Despite its small size, the drive unit according to the present invention can produce sufficient output characteristics for a power source of an electric vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Embodiments of the present invention are described with reference to the following figures: Fig. 1 shows the appearance of a power-assisted bicycle according to a first embodiment; Fig. 2 is a sectional view of a drive unit according to the first embodiment; Fig. 3 is a sectional view of the drive unit according to the first embodiment and shows an enlarged view of the vicinity of an engine; Fig. 4 is a sectional view of a one-way clutch provided in the drive unit according to the first embodiment; Fig. 5 is a sectional view of a drive unit according to a second embodiment; Fig. 6 is a sectional view of the drive unit according to the second embodiment, showing an enlarged view of the vicinity of an engine; Fig. 7 is a sectional view of a drive unit according to a third embodiment; Fig. 8 is a sectional view of the drive unit according to the third embodiment, showing an enlarged view of the vicinity of an engine; Fig. 9 is a sectional view of a drive unit according to a fourth embodiment; Fig. 10 is a sectional view of the drive unit according to the fourth embodiment, showing an enlarged view of the vicinity of an engine; Fig. 11 is a sectional view of a drive unit according to a fifth embodiment; Fig. 12 is a sectional view of the drive unit according to the fifth embodiment, showing an enlarged view of the vicinity of an engine; Fig. 13 is a sectional view of a drive unit according to a sixth embodiment; Fig. 14 is a sectional view of a drive unit according to a seventh embodiment; Fig. 15 is a sectional view of the power unit according to the seventh embodiment, showing an enlarged view of the vicinity of an engine; Fig. 16 is a sectional view of a drive unit according to an eighth embodiment; Fig. 17 is a sectional view of the drive unit according to the eighth embodiment, showing an enlarged view of the vicinity of an engine; Fig. 18 is a sectional view of a drive unit according to a ninth embodiment; Fig. 19 is a sectional view of a drive unit according to a tenth embodiment; Fig. 20 is a sectional view of a drive unit according to an eleventh embodiment; Fig. 21 is a sectional view of the drive unit according to the eleventh embodiment, showing an enlarged view of the vicinity of an engine; Fig. 22 is a sectional view of a drive unit according to a twelfth embodiment; and Fig. 23 is a sectional view of the drive unit according to the twelfth embodiment, showing an enlarged view of the vicinity of an engine. DESCRIPTION OF THE EMBODIMENTS

[0011] A drive unit and an electric vehicle incorporating the drive unit according to the present invention will be described in detail below. Each of the embodiments described below is merely an example, and the present invention is not limited to the following embodiments. All forms obtained by selectively combining the embodiments and modification examples described below are encompassed by the present invention. [First embodiment]

[0012] In the following, with reference to the Fig. 1 to 4, a first embodiment of a drive unit and an electric vehicle in the present invention is described.

[0013] Fig. Fig. 1 is a right side view showing the appearance of a power-assisted bicycle 1, which is an electric vehicle according to the first embodiment. Note that the electric vehicle in the present invention is not limited to the power-assisted bicycle 1 and may be an electric vehicle that travels by the power of a motor. The power-assisted bicycle 1 in the present invention is not limited to a sports bicycle as shown in Fig. 1, and may be, for example, a city bike, a folding bicycle, or the like. Hereinafter, the front-rear, left-right, and up-down directions in the embodiments of the present invention mean the front-rear, left-right, and up-down directions with respect to a state in which a rider sits on a saddle 5 of the power-assisted bicycle 1 and looks at the handlebar 4.

[0014] As in Fig. 1, the power-assisted bicycle 1 comprises a frame 2, a front wheel 3A, a rear wheel 3B, the handlebar 4 and the saddle 5, similar to a typical bicycle.

[0015] The frame 2 is a frame that connects the front wheel 3A, the rear wheel 3B, the handlebar 4, the saddle 5, and the like. The frame 2 includes a plurality of tubes. A steering head 2A, front forks 2B, a top tube 2C, a down tube 2D, a seat tube 2E, seat stays 2F, and chain stays 2G are provided as the plurality of tubes.

[0016] The power-assisted bicycle 1 further comprises a drive unit 20 and an energy storage device 10 that supplies the drive unit 20 with electrical energy. The power-assisted bicycle 1 has the function of combining the driving force (drive power of a human force) resulting from the pedaling force of a rider with the power of a motor 40 (see the later-described Fig. 2) to support the drive unit 20.

[0017] As described in detail later, a portion of the drive unit 20 is housed in the down tube 2D. Note that the drive unit 20 may be mounted on the outer side of the frame 2 instead of being housed in the down tube 2D.

[0018] The drive unit 20 has a pair of crank arms 6, each of which has pedals 7 attached to it. The crank arms 6 are provided on the left and right sides of the bicycle with power assistance 1, one for each side. The other end portions of the pair of crank arms 6 are both connected to a crankshaft 30 (see FIG. Fig. 2).

[0019] The drive unit 20 includes a gear or sprocket 70. The power-assisted bicycle 1 includes a chain 8 as a mechanism that transmits the rotational force of the gear 70 to the rear wheel 3B. The chain 8 couples the gear 70 to a rear sprocket 11 provided on the rear wheel 3B. Note that the gear 70 and the rear sprocket 11 may be coupled by a belt or shaft drive.

[0020] The energy storage device 10 is an energy source device that supplies the drive unit 20 with electrical energy. In a Fig. In the example shown in Figure 1, the energy storage device 10 is mounted outside the down tube 2D. Note that the position of the energy storage device 10 is not limited to the down tube 2D, and this device may be mounted on the top tube 2C or the seat tube 2E. Alternatively, the energy storage device 10 may be incorporated into the frame 2.

[0021] Preferably, a secondary battery is used as a battery housed in the energy storage device 10. Alternatively, a primary battery may be used. The voltage of the energy storage device 10 may, for example, be in the range of 12 V to 48 V inclusive. The energy storage device 10 may be provided with a voltage converter circuit. The voltage converter circuit may be provided in the energy storage device 10 or external to the energy storage device 10.

[0022] Next, with reference to Fig. 2 the drive unit 20 according to the first embodiment is described. Fig. 2 is a sectional view of the drive unit 20.

[0023] As in Fig. 2, the drive unit 20 comprises: the motor 40 for applying rotational force to assist the pedaling force on the pedals 7 (cf. Fig. 1); a housing 31 which houses the motor 40; and the crankshaft 30 rotatably mounted on the housing 31. The drive unit 20 is a so-called center unit type drive unit.

[0024] The drive unit 20 further includes: a human power transmission body 61 mounted to rotate integrally with the crankshaft 30 and rotated by a human power drive; an output body 62 that outputs the rotational power of the engine 40; the gear 70 that outputs the rotational power of the output body 62; and a power transmission mechanism 50 that brakes the rotational power of the engine 40 and transmits it to the gear 70 via the output body 62.

[0025] As described in detail later, the output body 62 functions as a power combining body where the rotational force of the driving power of a human power and the rotational force of the motor 40 are combined. In the present embodiment, the power transmission mechanism 50 is constructed of two stages of reduction mechanisms and includes: a planetary gear mechanism (first power transmission mechanism) 51, which is a first-stage speed reduction mechanism; and a second speed reduction mechanism (second power transmission mechanism) 52, which is a second-stage speed reduction mechanism.

[0026] As in Fig. As shown in Figure 2, the motor 40 includes a stator 41, a rotor 42, and a motor shaft 43 that rotates integrally with the rotor 42. In the present embodiment, the motor 40 is an internal rotor type motor. As described above, the motor 40 is housed in the housing 31.

[0027] The stator 41 is secured to the inner side of the housing 31 by press fitting, adhesive, or a pin. The rotor 42 has an annular shape having a circular opening portion 44 (see Fig. 3) at the center of rotation, and is disposed inside the stator 41. As described in detail later, a sun gear 511, a ring gear 512, planetary gears 513, and a planetary gear axle 514, which are gears constituting the planetary gear mechanism 51, are disposed radially inside the opening portion 44.

[0028] The motor shaft 43 is the output shaft of the motor 40 and is arranged such that the rotation axis runs along the axial direction of the crankshaft 30. The motor shaft 43 is rotatably supported by bearings 320, 321, and 322 provided in the housing 31, so that it is rotatable with respect to the housing 31. The rotor 42 and the motor shaft 43 are fixed to each other, for example, by splines.

[0029] The housing 31 is a member that forms an outer shell of the drive unit 20. The housing 31 is primarily made of metal, such as aluminum, stainless steel, or magnesium. Alternatively, a non-metallic material may be used. There are no specific restrictions on the material of the housing 31.

[0030] The housing 31 includes a first split body 311 constituting the right half of the housing 31; and a second split body 312 constituting the left half of the housing 31. The first split body 311 and the second split body 312 are connected to each other with a fastening member 34 such as a screw. By joining the first split body 311 and the second split body 312 together, the hollow housing 31 is formed. Note that there are no specific restrictions on the size, shape, thickness, and the like of the housing 31. The space formed in the housing 31 may be closed or unclosed.

[0031] The first split body 311 has a leftward protruding portion 3111. The ring gear 512 included in the planetary gear mechanism 51 is attached to the protruding portion 3111.

[0032] The human power transmission body 61, which is part of the output body 62, the planetary gear mechanism 51, and the second speed reduction mechanism 52 are accommodated in the housing 31 in addition to the motor 40. The housing 31 is provided at its opposite ends with through holes 314 and 315 through which the crankshaft 30 passes.

[0033] In the present embodiment, a part of the casing 31 is housed in the down tube 2D. Between the casing 31 and the down tube 2D (frame 2), a heat dissipation member 33 is arranged, which transfers the heat of the casing 31 to the down tube 2D. That is, the heat of the casing 31 is transferred to the down tube 2D via the heat dissipation member 33. In general, the temperature of the casing 31 tends to be increased by the heat of the motor 40 and the like housed in the casing 31. As in the present embodiment, by disposing the heat dissipation member 33 between the casing 31 and the down tube 2D, the temperature of the casing 31 can be reduced and the reliability of the power unit 20 can be improved. Note that it can be configured so that the heat of the casing 31 can be transferred to members other than the down tube 2D via the heat dissipation member 33.

[0034] For example, an elastic body that has higher thermal conductivity than typical resin and is compressible can be used as the heat dissipation member 33. An example of a preferred heat dissipation member 33 is a heat release sheet comprising a flexible resin and a thermally conductive filler dispersed in the resin. The thickness of the heat dissipation member 33 is, for example, in the range between 0.3 mm and 2 mm, inclusive. Note that a conventional, publicly known member can be used as the heat dissipation member 33.

[0035] The heat dissipation member 33 may be adhesive and adhere to the surface or the like of the casing 31 or the down tube 2D. When the heat dissipation member 33 adheres to the surface or the like of the casing 31 or the down tube 2D, the heat dissipation member 33 can be easily installed. Note that the heat dissipation member 33 may be attached to the surface or the like of the casing 31 or the down tube 2D using an adhesive, an adhesive tape, or the like.

[0036] The crankshaft 30 is a cylindrical member that is driven by a human power drive. The crankshaft 30 rotates relative to the drive unit 20. In the present embodiment, the crankshaft 30 is made of a hollow member, but may also be made of a solid member instead.

[0037] The opposite ends of the crankshaft 30 protrude from the housing 31. A pair of crank arms 6 (cf. Fig. 1) is provided at opposite ends of the crankshaft 30. The crankshaft 30 is rotatably supported on the housing 31 (frame 2) by bearings 324 and 325. The bearings 324 and 325 are formed, for example, from ball bearings.

[0038] The power transmission mechanism 50 is a mechanism that decelerates the rotational force of the motor 40 and transmits the rotational force of the motor 40 to the gear 70 via the output shaft 62. In the present embodiment, the power transmission mechanism 50 is composed of two stages of speed reduction mechanisms and includes: the planetary gear mechanism 51, which is the first-stage speed reduction mechanism; and the second speed reduction mechanism 52, which is the second-stage speed reduction mechanism. Note that the power transmission mechanism 50 may include an accelerator mechanism.

[0039] As will be described in detail later, the planetary gear mechanism 51 includes: the motor shaft 43 as the sun gear 511; the ring gear 512 arranged on a concentric circle of the sun gear 511; the planetary gears 513 that mesh with the sun gear 511 and the ring gear 512; the planetary gear axles 514; and a planetary carrier 515 as an output shaft. The ring gear 512 is non-rotatably fixed to the housing 31 by being attached to the protruding portion 3111 of the housing 31. The rotational power of the motor 40 output from the planetary carrier 515 is transmitted to the second speed reduction mechanism 52 via a one-way clutch 53.

[0040] When rotational force is applied to the planetary carrier 515 in one direction (hereinafter referred to as the "forward direction") for accelerating the power-assisted bicycle 1 in the traveling direction, the one-way clutch 53 transmits the rotational force to a first transmission gear 521 provided in the second speed reduction mechanism 52. When rotational force is applied to the planetary carrier 515 in the direction opposite to the forward direction, the one-way clutch 53 does not transmit the rotational force to the first transmission gear 521. When rotational force is applied to the first transmission gear 521 in the forward direction, the one-way clutch 53 does not transmit the rotational force to the planetary carrier 515.

[0041] The second speed reduction mechanism 52 includes the first transmission gear 521 and a second transmission gear 522. The rotational axis of the first transmission gear 521 is concentrically positioned on the rotational axis of the sun gear 511. The rotational axis of the second transmission gear 522 is concentrically positioned on the rotational axis of the crankshaft 30. This means that the outer diameter of the second transmission gear 522 is larger than the outer diameter of the first transmission gear 521. The number of teeth of the second transmission gear 522 is greater than the number of teeth of the first transmission gear 521.

[0042] The first transmission gear 521 is arranged radially outwardly of the planetary carrier 515, and the rotational power of the motor 40 is transmitted to this gear via the one-way clutch 53. The first transmission gear 521 is rotatably supported on the housing 31 by a bearing 323 (first bearing).

[0043] The second transmission gear 522 meshes with the toothed portions provided on the outer peripheral surface of the output body 62. Accordingly, the rotational force of the motor 40 transmitted to the second transmission gear 522 is transmitted to the output body 62.

[0044] Here, the bearing 323 (first bearing) that rotatably supports the first transmission gear 521 and the one-way clutch 53 can be arranged at positions that overlap in the axial direction of the crankshaft 30. Accordingly, a reduction in the size of the drive unit 20 can be facilitated.

[0045] Note that the second speed reduction mechanism 52 and a bearing 320 (second bearing) provided at the distal end (right end) of the motor shaft 43 as the sun gear 511 and rotatably supporting the motor shaft 43 are arranged at positions overlapping in the axial direction of the crankshaft 30. Accordingly, a reduction in the size of the drive unit 20 can be facilitated.

[0046] Note that in the present embodiment, the second speed reduction mechanism 52 includes two gears composed of the first transmission gear 521 and the second transmission gear 522. However, the number of gears may be one, three, or more. The power transmission mechanism 50 may be a single-stage speed reduction mechanism or a speed reduction mechanism with three or more stages.

[0047] The human power transmission body 61 is a cylindrical member extending along the axial direction of the crankshaft 30 and disposed on the outer peripheral portion of the crankshaft 30 in the housing 31. The human power transmission body 61 rotates integrally with the crankshaft 30. In the present embodiment, the human power transmission body 61 is divided into a first human power transmission body 611 and a second human power transmission body 612. Note that the human power transmission body 61 may be constructed of a single member.

[0048] The first human power transmission body 611 is coupled to the crankshaft 30. Grooves or splines are formed on the inner peripheral surface of the first human power transmission body 611, which are attached to the crankshaft 30. Note that a missing tooth portion may be provided at a location where the first human power transmission body 611 and the crankshaft 30 fit together. This enables positioning in the assembly direction and facilitates assembly. The first human power transmission body 611 and the crankshaft 30 can be joined by press fitting or with a screw.

[0049] The second human power transmission body 612 is arranged on the right side of the first human power transmission body 611 in the axial direction of the crankshaft 30. The second human power transmission body 612 is coupled to the first human power transmission body 611 and transmits the rotational force to the output body 62.

[0050] In the present embodiment, grooves or serrations are formed on the outer peripheral surface of the right end of the first human power transmission body 611, which are attached to the inner peripheral surface of the left end of the second human power transmission body 612. Accordingly, the first human power transmission body 611 and the second human power transmission body 612 are coupled to each other.

[0051] There are no specific restrictions on the lengths of the first human power transmission body 611 and the second human power transmission body 612 in the axial direction of the crankshaft 30, as long as the rotational force can be transmitted to the driven body 62 by the driving power of a human power. For example, each of the lengths is in the range of 5% to 40% inclusive of the length of the crankshaft 30 in the axial direction. In the present embodiment, the length of the first human power transmission body 611 in the axial direction of the crankshaft 30 is longer than the length of the second human power transmission body 612. Note that the length of the first human power transmission body 611 in the axial direction of the crankshaft 30 may be shorter than the length of the second human power transmission body 612.

[0052] The output body 62 is a cylindrical member that extends along the axial direction of the crankshaft 30 and is arranged on the outer peripheral portion of the crankshaft 30. The rotational axis of the output body 62 is positioned concentrically on the rotational axis of the crankshaft 30.

[0053] The length of the output body 62 in the axial direction of the crankshaft 30 is shorter than the length of the crankshaft 30 and is, for example, between 10% and 50% of the length of the crankshaft 30 in the axial direction. The right end of the output body 62 protrudes from the housing 31 through the through hole 314 in the housing 31. The output body 62 is rotatably mounted on the housing 31 by the bearing 324.

[0054] On the outer peripheral surface of the output body 62, tooth portions are provided to mesh with the tooth portions of the second transmission gear 522. Accordingly, the rotational power of the motor 40 is transmitted to the output body 62 via the second transmission gear 522.

[0055] In the present embodiment, a one-way clutch 63 is provided between the second human power transmission body 612 and the driven body 62. When the rotational force in the forward direction is applied to the second human power transmission body 612, the one-way clutch 63 transmits the rotational force to the driven body 62. When the rotational force in the opposite direction to the forward direction is applied to the second human power transmission body 612, the one-way clutch 63 does not transmit the rotational force to the driven body 62. When the rotational force in the forward direction is transmitted to the driven body 62 via the power transmission mechanism 50, the one-way clutch 63 does not transmit the rotational force to the second human power transmission body 612. The one-way clutch 63 also functions as a bearing and rotatably supports the driven body 62.It is noted that the configuration of the one-way clutch 63 will be described later.

[0056] Grooves or teeth are machined into a portion of the output body 62 that protrudes from the housing 31, and these teeth are attached to the gear 70. Accordingly, the gear 70 rotates integrally with the output body 62. It is noted that an elastic element for regulating the movement of the gear 70 may be arranged between the output body 62 and the gear 70.

[0057] Note that the human power transmission body 61 and the driven body 62 are provided separately in the present embodiment, but may be configured integrally instead. For example, the human power transmission body 61 may not necessarily be provided, and only the driven body 62 may be provided. In this case, by transmitting the rotational force of the crankshaft 30 due to the driving power of human power to the driven body 62, the power-assisted bicycle 1 is enabled to move in the forward direction.

[0058] A one-way clutch may be arranged between the output body 62 and the gear 70. When the rotational force is applied to the output body 62 in a forward direction, the one-way clutch transfers the rotational force to the gear 70. When the rotational force is applied to the output body 62 in the opposite direction to the forward direction, the one-way clutch does not transfer the rotational force to the gear 70.

[0059] Here, the power transmission path in the drive unit 20 will be described. First, the power transmission path of the drive power of a human power applied to the pedals 7 will be described. The rider presses down the pedals 7 of the power-assisted bicycle 1, thereby rotating the crankshaft 30 in the forward direction. When the crankshaft 30 rotates in the forward direction, the human power transmission body 61 attached to the outer peripheral portion of the crankshaft 30 rotates forward integrally with the crankshaft 30. The rotational force of the human power transmission body 61 rotating in the forward direction is transmitted to the output body 62 to output the rotational power of the motor 40. The output body 62 and the gear 70 attached to the output body 62 rotate integrally in the forward direction.When the gear 70 rotates in the forward direction, the forward rotational force is transmitted to the rear wheel gear 11 via the chain 8, and the rear wheel gear 11 and the rear wheel 3B rotate in the forward direction. Accordingly, the power-assisted bicycle 1 moves forward.

[0060] Next, the power transmission path of the rotational power of the motor 40 will be described. When the motor shaft 43 of the motor 40 rotates in the forward direction, the rotational power is transmitted to the output body 62 via the power transmission mechanism 50, which includes the planetary gear mechanism 51 and the second speed reduction mechanism 52. That is, the output body 62 functions as a power combination body where the rotational power from the human power transmission body 61 through the above-described human power drive power and the rotational power of the motor 40 are combined. The rotational power of the motor 40 transmitted to the output body 62 is transmitted to the rear wheel 3B through the power transmission path similar to the above-described human power drive power, and the power-assisted bicycle 1 travels forward.

[0061] The drive unit 20 includes torque detection sections 80 for detecting the torque of the driving power of a human force; and a control board 81 on which a control device (not shown) is arranged for controlling and / or regulating the output of the motor 40 in response to the detected torque and for achieving a suitable power assist function. The drive unit 20 further includes a rotation detection section 82 for detecting the rotation of the crankshaft 30.

[0062] The torque detecting sections 80 are provided on the outer peripheral portion of the first human power transmission body 611 and detect the load applied to the first human power transmission body 611. For example, a strain sensor that detects physical strain or a strain sensor that detects magnetic strain can be used as each torque detecting section 80. For example, a scheme can be used in which a paint that emits light in response to a mechanical stimulus is applied to the outer peripheral portion of the human power transmission body 611, and the light is detected by an optical sensor.

[0063] In the present embodiment, the drive unit 20 includes a total of two torque detecting sections 80, one at each of the circumferentially opposite positions on the outer peripheral portion of the first human power transmission body 611. Note that the number of torque detecting sections 80 provided on the outer peripheral portion of the first human power transmission body 611 may be as few as one or three or more. The installation positions of the torque detecting sections 80 are not limited to the outer peripheral portion of the first human power transmission body 611 and may be located, for example, on the outer peripheral portion of the second human power transmission body 612 or the crankshaft 30.

[0064] The control device is arranged on the control board 81 and controls and / or regulates the rotation of the motor 40 based on the torque detected by each torque detecting section 80. The control device controls and / or regulates the rotation of the motor 40 based on detection information from the rotation detecting section 82. A conventional, publicly known configuration can be used as the configuration of the control device.

[0065] The torque detecting section 80 and the rotation detecting section 82 can communicate with the control device via signal lines or wireless signals. When communicating via wireless signals, no cables are required to connect the torque detecting section 80 and the rotation detecting section 82 to the control device, facilitating a reduction in the size of the drive unit 20.

[0066] In the present embodiment, the control board 81 is constructed from a single board having through holes through which the crankshaft 30 and the engine 40 pass. The control board 81 is arranged such that the substantially normal direction of the surface (thickness direction) can run along the axial direction of the crankshaft 30. Note that the control board 81 may be composed of multiple boards.

[0067] A portion of the control board 81 is connected to the motor 40. The portion of the control board 81 is connected to the motor 40, and the control board 81 and the motor 40 are arranged close to each other, which can shorten the cable connecting the control board 81 to the motor 40, thereby reducing the size of the drive unit 20.

[0068] A part of the control board 81 is connected to the second split body 312. In the present embodiment, the control board 81 and the second split body 312 are connected to each other via a heat dissipation member 35. A similar configuration to that of the heat dissipation member 33 disposed between the casing 31 and the downpipe 2D can be used for the heat dissipation member 35.

[0069] The control board 81 may, for example, be provided with a rotor rotation detection section 85 to detect the rotation of the rotor 42. The rotor rotation detection section 85 includes, for example, a Hall element. The Hall element detects the change in the magnetic field caused by the rotation of the rotor 42, thus enabling the measurement of the number of revolutions of the rotor 42. Note that the magnetic force detected by the Hall element may be the magnetic force of a component that rotates together with the rotor 42.

[0070] A cable 83 extending from the outer side of the drive unit 20 is connected to the control board 81 via a connector 84. Note that the connector 84 is a separate element from the drive unit 20. The cable 83 is connected, for example, to the energy storage device 10 (see FIG. Fig. 1) and supplies power to the electronic devices arranged on the control or regulation board 81.

[0071] The connector 84 includes a first portion 841 extending substantially in the normal direction of a surface of the control board 81, and a second portion 842 extending in a direction inclined from the substantially normal direction of the surface of the control board 81. In the present embodiment, the second portion 842 is configured to be substantially perpendicular to the first portion 841. This means that the connector 84 is bent substantially perpendicularly. Accordingly, the length of the connector 84 in the left-to-right direction can be reduced, thereby reducing the size of the drive unit 20.

[0072] The rotation detecting section 82 detects the number of revolutions of the crankshaft 30. The rotation detecting section 82 internally includes, for example, a Hall element and is arranged at a position overlapping the magnet 86 provided on the outer peripheral portion of the first human power transmitting body 611. The Hall element detects the change in the magnetic field of the magnet due to the rotation of the crankshaft 30, thus enabling the measurement of the number of revolutions of the crankshaft 30. Note that the configuration of the rotation detecting section 82 is not limited to this. The rotation detecting section 82 may be, for example, an inertial sensor such as an acceleration sensor or a gyroscope sensor.

[0073] In the present embodiment, the rotation detecting section 82 is arranged on the control board 81. By arranging the rotation detecting section 82 on the control board 81, the rotation detecting section 82 can be arranged without increasing the number of boards. Accordingly, a reduction in the size of the drive unit 20 can be facilitated.

[0074] Next, with further reference to Fig. 3 the motor 40 and the gears forming the planetary gear mechanism 51 are described in detail. Fig. 3 is an enlarged view of the surroundings of the engine 40 in Fig. 2.

[0075] As in Fig. 3, the motor 40 includes the stator 41, the rotor 42, and the motor shaft 43 which rotates integrally with the rotor 42.

[0076] The stator 41 is fixed to the inner side of the housing 31 by press fitting, adhesive, screwing, or pinning. In this case, an elastic member such as a rubber member or urethane may be provided between the stator 41 and the housing 31. By providing the elastic member, vibration of the stator 41 can be reduced. A heat-releasing film or heat-releasing paste (heat-releasing grease, heat-releasing gel, etc.) may be provided between the stator 41 and the housing 31. This can improve the heat dissipation property of the motor 40 and protect the motor 40 from overheating and vibration.

[0077] Preferably, the outer diameter of the stator 41 is 100 mm or less. More preferably, the outer diameter is 90 mm or less. By having the stator 41 with an outer diameter of 100 mm or less, the reduction in size of the drive unit 20 can be further facilitated. The lower limit of the outer diameter of the stator 41 is, for example, 60 mm.

[0078] The rotor 42 has an annular shape with a circular opening portion 44 at the rotation center and is disposed inside the stator 41. Preferably, the inner diameter of the rotor 42 is equal to or larger than 30 mm. More preferably, the inner diameter is equal to or larger than 40 mm. By having the rotor 42 with an inner diameter of 30 mm or larger, the arrangement of the gears constituting the planetary gear mechanism 51 inside the opening portion 44 of the rotor 42 in the radial direction is facilitated. The upper limit of the inner diameter of the rotor 42 is, for example, 100 mm.

[0079] The motor shaft 43 is a cylindrical shaft-shaped member extending along the axial direction of the crankshaft 30 (left-right direction) and rotating integrally with the rotor 42. The motor shaft 43 is arranged such that its rotation axis lies along the axial direction of the crankshaft 30. The motor shaft 43 is rotatably supported by bearings 320, 321, and 322 provided in the housing 31, so that it is rotatable with respect to the housing 31.

[0080] The rotor 42 and the motor shaft 43 are secured to each other by splines. Note that the rotor 42 and the motor shaft 43 can be secured by press fitting, shrink fitting, cooling fitting, or the like. When the rotor 42 and the motor shaft 43 are secured, an elastic member, such as a rubber member or urethane, can be provided between the rotor 42 and the motor shaft 43.

[0081] The motor shaft 43 is arranged such that the central rotation axis passes through the center of the ring gear 512 included in the planetary gear mechanism 51 described later and penetrates the ring gear 512. Tooth portions 43A are provided on the surface of the motor shaft 43, which mesh with the tooth portions 513A of the planetary gears 513 provided in the planetary gear mechanism 51. The motor shaft 43 constitutes the sun gear 511 of the planetary gear mechanism 51. Note that the tooth portions in this description indicate tooth shapes provided in the surfaces of the gears and include areas that do not mesh with the tooth portions of other gears.

[0082] As in Fig. As shown in Figure 3, the planetary gear mechanism 51 includes: the motor shaft 43 as the sun gear 511; the ring gear 512 disposed on the concentric circle of the sun gear 511; the planet gears 513 meshing with the sun gear 511 and the ring gear 512; the planet gear axles 514; and the planet carrier 515 as the output shaft.

[0083] The ring gear 512 has an annular shape. Toothed portions 512A are formed over the entire area of ​​the inner peripheral surface. The ring gear 512 is non-rotatably fixed to the housing 31 by being fitted onto the protruding portion 3111 of the housing 31.

[0084] The tooth portions 513A are formed over the entire circumference of each planetary gear 513, which meshes with the sun gear 511 and the ring gear 512. The planetary gear axes 514 penetrate the centers of the respective planetary gears 513 and keep these planetary gears 513 freely rotatable. A bushing 38 having an L-shape in a sectional view taken in the axial direction is arranged outside each planetary gear axes 514 in the radial direction and configured to allow the corresponding planetary gear axes 514 to rotate. Note that the bearing 323 is not necessarily provided, and only the bushing 38 may be provided. The planetary carrier 515 supports the planetary gears 513 for orbiting. The rotational axis of the planetary carrier 515 is positioned concentrically on the rotational axis of the sun gear 511. The planet carrier 515 is rotatably supported in the bearing 323 provided in the housing 31.Bearing 323, for example, is made of a ball bearing.

[0085] As in Fig. 3, the rotor 42 and the tooth portions 43A of the motor shaft 43 (sun gear 511), the tooth portions 512A of the ring gear 512, and the tooth portions 513A of the planetary gears 513 are arranged at overlapping positions in the axial direction of the crankshaft 30. Accordingly, the size of the drive unit 20 can be reduced in the axial direction of the crankshaft 30. Note that the tooth portions 43A of the motor shaft 43 (sun gear 511), the tooth portions 512A of the ring gear 512, and the tooth portions 513A of the planetary gears 513 may be arranged at positions overlapping the stator 41 instead of the rotor 42 in the axial direction of the crankshaft 30. In this case, too, the size of the drive unit 20 can be reduced.

[0086] At least parts of the tooth portions 43A of the motor shaft 43, the tooth portions 512A of the ring gear 512, and the tooth portions 513A of the planetary gears 513 are arranged in the opening portion 44 of the rotor 42 in the radial direction. Accordingly, the drive unit 20 can be further reduced in size.

[0087] Metal gears and resin gears can be used as the gears constituting the planetary gear mechanism 51. Using resin gears can reduce the weight of the drive unit 20 and also reduce noise during travel. The resin material can be, for example, polyacetal, nylon 46, nylon 66, PEEK, or a thermosetting resin, or it can be a super-engineering plastic.

[0088] The gears constituting the planetary gear mechanism 51 can be spur gears or helical gears. The use of helical gears can reduce noise during travel. Preferably, the gears constituting the planetary gear mechanism 51 are lubricated with grease. Note that the gears constituting the planetary gear mechanism 51 can be lubricated with lubricating oil. Each gear can have a non-arc shape resembling a gear wheel shape.

[0089] Next, with further reference to Fig. 4 the overrunning clutch 63 is described. Fig. 4 is a sectional view of the one-way clutch 63.

[0090] As in Fig. As shown in Figure 2, the one-way clutch 63 is disposed between the second human power transmission body 612 and the driven body 62. The one-way clutch 63 is disposed closer to the gear 70 in the axial direction of the crankshaft 30 than the central portion of the crankshaft 30 in the axial direction. As described above, when the rotational force is applied in the forward direction to the second human power transmission body 612, the one-way clutch 63 transmits the rotational force to the driven body 62. When the rotational force is applied in the opposite direction to the forward direction to the second human power transmission body 612, the one-way clutch 63 does not transmit the rotational force to the driven body 62.

[0091] As in Fig. As shown in Fig. 4, the one-way clutch 63 includes an inner gear body 63A and an outer gear body 63B covering the outer peripheral portion of the inner gear body 63A. The inner gear body 63A is provided on the outer peripheral portion of the second human power transmission body 612. Note that the inner gear body 63A may be provided integrally with the second human power transmission body 612. The outer gear body 63B is provided on the inner peripheral portion of the output body 62. Note that the outer gear body 63B may be formed integrally with the output body 62.

[0092] The sprags 63C as engagement elements are arranged between the inner gear body 63A and the outer gear body 63B. This means that the one-way clutch 63 is a so-called sprag-type one-way clutch. The sprags 63C are aligned in an extended position between the inner gear body 63A and the outer gear body 63B, thereby enabling the transmission of the rotational force. On the other hand, the sprags 63C slide between the inner gear body 63A and the outer gear body 63B, thereby preventing the transmission of the rotational force. The shape of each sprag 63C is not limited to the Fig. 4 and may, for example, have a cylindrical shape.

[0093] Balls 63D as rolling elements are further arranged between the inner gear body 63A and the outer gear body 63B. When the outer gear body 63B is rotatable with respect to the inner gear body 63A, that is, when the rotational force cannot be transmitted, the one-way clutch 63 receives the radial load, functions as a bearing, and rotatably supports the second body 612 for transmitting the human power. As shown in Fig. As shown in Figure 4, the one-way clutch 63 includes four balls 63D, and the four balls 63D are arranged at substantially regular intervals in the circumferential direction. Note that the rolling elements are not limited to the balls 63D and may be cylindrically shaped elements. [Second embodiment]

[0094] In the following, with reference to the Fig. 5 and Fig. 6 describes a second embodiment of a drive unit in the present invention. Fig. 5 is a sectional view of a drive unit 20A according to the second embodiment. Fig. 6 shows an enlarged view of the surroundings of a motor 40A in Fig. 5. In the following, the same symbols are assigned to the components common to those in the first embodiment, redundant description of these components is omitted, and the differences from the first embodiment are mainly described.

[0095] As in Fig. As shown in Fig. 5, the drive unit 20A includes: the motor 40A for applying rotational power to assist the pedaling force to the pedals 7; a housing 31 that houses the motor 40A; and a crankshaft 30 rotatably mounted on the housing 31. Similar to the drive unit 20 in the first embodiment, the drive unit 20A is a so-called center unit type drive unit.

[0096] Similar to the drive unit 20 according to the first embodiment, the drive unit 20A further includes: a human power transmission body 61 mounted to rotate integrally with the crankshaft 30 and rotated by a human power drive; an output body 62 that outputs the rotational power of the engine 40A; a gear 70 that outputs the rotational power of the output body 62; and a power transmission mechanism 50 that brakes the rotational power of the engine 40A and transmits the power to the gear 70 via the output body 62.

[0097] As in Fig. As shown in Fig. 6, the motor 40A of the drive unit 20A in the second embodiment is a so-called external rotor motor in which a rotor 42A is arranged radially outside a stator 41A. The use of the external rotor type facilitates the output of higher torque than the internal rotor type motor.

[0098] As in Fig. As shown in Fig. 6, the rotor 42A and the tooth portions 43A of a motor shaft 43, the tooth portions 512A of a ring gear 512, and the tooth portions 513A of planetary gears 513 are arranged at overlapping positions in the axial direction of the crankshaft 30. Accordingly, even in the case of using an external rotor motor, the size of the drive unit 20A can be reduced in the axial direction of the crankshaft 30. [Third Embodiment]

[0099] Next, with reference to the Fig. 7 and Fig. 8 describes a third embodiment of a drive unit in the present invention. Fig. 7 is a sectional view of a drive unit 20B according to the third embodiment. Fig. Figure 8 shows an enlarged view of the surroundings of an engine 40 in Fig. 7. In the following, the same symbols are assigned to the components common to those in the first embodiment, redundant description of these components is omitted, and differences from the first embodiment are mainly described.

[0100] As in Fig. 7, the drive unit 20B, similar to the drive unit 20 according to the first embodiment, includes: the motor 40 for applying rotational power to assist pedaling force on pedals 7; a housing 31 accommodating the motor 40; and a crankshaft 30 rotatably mounted on the housing 31.

[0101] The drive unit 20B further includes: a human power transmission body 61 mounted to rotate integrally with the crankshaft 30 and rotated by human power input; an output body 62 that outputs the rotational power of the engine 40; a gear 70 that outputs the rotational power of the output body 62; and a power transmission mechanism 50B that brakes the rotational power of the engine 40 and transmits the power to the gear 70 via the output body 62. The power transmission mechanism 50B is composed of two stages of speed reduction mechanisms and includes: a planetary gear mechanism 51, which is a first-stage speed reduction mechanism; and a second speed reduction mechanism 52, which is a second-stage speed reduction mechanism.

[0102] As in Fig. As shown in Fig. 8, the configuration of a planetary carrier 515B included in the planetary gear mechanism 51 differs from that of the planetary carrier 515 of the drive unit 20 in the first embodiment. Specifically, the planetary carrier 515B has a hollow portion 5151 centered on the rotation axis, and a projection member 36 and a bearing 326 are disposed in the hollow portion 5151.

[0103] The protrusion member 36 is fitted into a concavity 3112 formed in a first split body 311 and is non-rotatably fixed to the first split body 311. The material of the protrusion member 36 is not particularly limited. However, this member is made of, for example, a metal material containing iron or aluminum as a main component. By providing the protrusion member 36, the rotation of the planetary carrier 515B can be stabilized.

[0104] The bearing 326 rotatably supports the planetary carrier 515B on the housing 31. By providing the bearing 326 in the hollow portion 5151 of the planetary carrier 515B, the size of the drive unit 20B can be reduced. [Fourth Embodiment]

[0105] Next, with reference to the Fig. 9 and Fig. 10 describes a fourth embodiment of a drive unit in the present invention. Fig. 9 is a sectional view of a drive unit 20C according to the fourth embodiment. Fig. 10 shows an enlarged view of the surroundings of an engine 40 in Fig. 9. In the following, the same symbols are assigned to the components common to those in the first embodiment, repeated description of these components is omitted, and the differences from the first embodiment are mainly described.

[0106] As in Fig. As shown in Fig. 9, the drive unit 20C, similar to the drive unit 20 according to the first embodiment, includes: the motor 40 for applying rotational power to assist pedaling force on pedals 7; a housing 31 accommodating the motor 40; and a crankshaft 30 rotatably mounted on the housing 31.

[0107] The drive unit 20C further includes: a human power transmission body 61 mounted to rotate integrally with the crankshaft 30 and rotated by human power input; an output body 62 that outputs the rotational power of the engine 40; a gear 70 that outputs the rotational power of the output body 62; and a power transmission mechanism 50C that brakes the rotational power of the engine 40 and transmits the power to the gear 70 via the output body 62. The power transmission mechanism 50C is composed of two stages of speed reduction mechanisms and includes: a planetary gear mechanism 51, which is a first-stage speed reduction mechanism; and a second speed reduction mechanism 52, which is a second-stage speed reduction mechanism.

[0108] As in Fig. As shown in Figure 10, the power transmission mechanism 50C of the drive unit 20C includes an output member 516 that meshes with a planetary carrier 515C, which forms the output shaft of the planetary gear mechanism 51. The output member 516 is a solid cylindrical member extending in the axial direction of the crankshaft 30. The output member 516 is arranged such that the rotational axis of the output member 516 is concentrically positioned on the rotational axis of the planetary carrier 515C. The output member 516 can stabilize the rotation of the planetary carrier 515C.

[0109] A protruding portion 5161, which protrudes outward in the radial direction from the output member 516, is formed over the entire circumference of the output member 516 at the central portion of the output member 516 in the axial direction. The output member 516 and the planetary carrier 515C mesh with each other in the left area of ​​the protruding portion 5161. This means that the output member 516 and the planetary carrier 515C do not mesh with each other in the right area of ​​the protruding portion 5161.

[0110] The output member 516 has a small-diameter portion 5162 formed to have a smaller diameter than the other portion in the right area of ​​the protruding portion 5161. A bearing 327 (third bearing) that rotatably supports the output member 516 to the housing 31 is arranged radially outside the small-diameter portion 5162. Accordingly, the output member 516 can be rotatably supported to the housing 31 without increasing the size of the power unit 20C. The bearing 327 (third bearing) and a first transmission gear 521 are arranged at positions overlapping in the axial direction of the crankshaft 30. Accordingly, a reduction in the size of the power unit 20C can be facilitated. [Fifth Embodiment]

[0111] In the following, with reference to the Fig. 11 and Fig. 12 describes a fifth embodiment of a drive unit in the present invention. Fig. 11 is a sectional view of a drive unit 20D according to the fifth embodiment. Fig. 12 shows an enlarged view of the surroundings of an engine 40D in Fig. 11. In the following, the same symbols are assigned to the components common to those in the fourth embodiment, redundant description of these components is omitted, and differences from the fourth embodiment are mainly described.

[0112] As in Fig. As shown in Fig. 11, the drive unit 20D includes: the motor 40D for applying rotational power to assist pedaling force on pedals 7; a housing 31 that houses the motor 40A; and a crankshaft 30 rotatably mounted on the housing 31. Similar to the drive unit 20C in the fourth embodiment, the drive unit 20D is a so-called center unit type drive unit.

[0113] Similar to the drive unit 20C according to the fourth embodiment, the drive unit 20D further includes: a human power transmission body 61 mounted to rotate integrally with the crankshaft 30 and rotated by a human power drive; an output body 62 that outputs the rotational power of the engine 40D; a gear 70 that outputs the rotational power of the output body 62; and a power transmission mechanism 50C that brakes the rotational power of the engine 40D and transmits the power to the gear 70 via the output body 62.

[0114] As in Fig. As shown in Fig. 12, the configuration of the motor 40D in the drive unit 20D according to the fifth embodiment differs from that of the drive unit 20C according to the fourth embodiment. Specifically, the motor 40D includes: a motor shaft 43D, which is an output shaft; a stator 41D fixed to the housing 31; and a rotor 42D fixed to the motor shaft 43D and having magnets 45D. The rotor 42D is arranged to face the stator 41D in a direction along the rotation axis of the motor shaft 43D. This means that the motor 40D is a so-called axial gap motor. By using the axial gap motor, the size of the motor 40D can be reduced, and the size reduction of the drive unit 20D is facilitated compared to an inner rotor type motor or an outer rotor type motor.

[0115] In the present embodiment, the rotor 42D is arranged only on one side (left side) of the stator 41D in the direction along the rotation axis of the motor shaft 43D. Accordingly, the motor 40D can be reduced in size, facilitating a reduction in the size of the drive unit 20D. Note that the rotor 42D may be arranged on the opposite sides of the stator 41D in the direction of the rotation axis of the motor shaft 43D.

[0116] The motor shaft 43D is rotatably supported on the housing 31 by bearings 320 and 321. The bearings 320 and 321 are arranged separately from each other in the direction along the rotational axis of the motor shaft 43D.

[0117] As in Fig. As shown in Fig. 12, the stator 41D and the tooth portions 43A of the motor shaft 43D, the tooth portions 512A of a ring gear 512, and the tooth portions 513A of the planetary gears 513 are arranged at overlapping positions in the axial direction of the crankshaft 30. Accordingly, even in the case of using the axial gap motor, the size of the drive unit 20D can be reduced in the axial direction of the crankshaft 30. [Sixth Embodiment]

[0118] Next, with reference to Fig. 13, a sixth embodiment of a drive unit in the present invention is described. Fig. 13 is a sectional view of a drive unit 20E according to the sixth embodiment. Hereinafter, the same reference numerals are assigned to the components common to those in the first embodiment. A repeated description of these components will be omitted, and the differences from the first embodiment will be mainly described.

[0119] As in Fig. 13, the drive unit 20E includes: a motor 40 for applying rotational power to assist pedaling force to pedals 7; a housing 31E accommodating the motor 40; and a crankshaft 30 rotatably mounted on the housing 31E.

[0120] Similar to the drive unit 20 according to the first embodiment, the drive unit 20E further includes: a human power transmission body 61 mounted to rotate integrally with the crankshaft 30 and rotated by human power input; an output body 62 outputting the rotational power of the engine 40; a gear 70 outputting the rotational power of the output body 62; and a power transmission mechanism 50 decelerating the rotational power of the engine 40 and transmitting the power to the gear 70 via the output body 62.

[0121] The housing 31E includes: a first split body 311E forming a right outer shell of the housing 31E; a second split body 312E forming a left outer shell of the housing 31E; and a third split body 313E located between the first split body 311E and the second split body 312E. The first split body 311E and the third split body 313E are joined together with a fastening member 341 such as a screw, and the second split body 312E and the third split body 313E are joined together with a fastening member 342 such as a screw. The housing 31E is constructed from these three split bodies, which facilitates the configuration of each split body and improves manufacturability. Note that the number of split bodies constituting the housing may be four or more.The space formed in the housing 31E may be closed or not closed.

[0122] The third split body 313E has a leftward protruding portion 3131. A ring gear 512 included in a planetary gear mechanism 51 is attached to the protruding portion 3131. [Seventh Embodiment]

[0123] Next, with reference to the Fig. 14 and Fig. 15 a seventh embodiment of a drive unit in the present invention is described. Fig. 14 is a sectional view of a drive unit 20F according to the seventh embodiment. Fig. 15 shows an enlarged view of the surroundings of an engine 40 in Fig. 14. In the following, the same symbols are assigned to the components common to those in the first embodiment, redundant description of these components is omitted, and differences from the first embodiment are mainly described.

[0124] As in Fig. As shown in Fig. 14, the drive unit 20F includes: the motor 40 for applying rotational power to assist the pedaling force on pedals 7; a housing 31F that houses the motor 40; and a crankshaft 30 rotatably mounted on the housing 31F. Similar to the housing 31E in the fifth embodiment, the housing 31F is constructed of three divided bodies: a first divided body 311F, a second divided body 312F, and a third divided body 313F.

[0125] The drive unit 20F further includes: a human power transmission body 61 mounted to rotate integrally with the crankshaft 30 and rotated by human power input; an output body 62 that outputs the rotational power of the engine 40; a gear 70 that outputs the rotational power of the output body 62; and a power transmission mechanism 50F that brakes the rotational power of the engine 40 and transmits the power to the gear 70 via the output body 62. The power transmission mechanism 50F is composed of two stages of speed reduction mechanisms and includes: a planetary gear mechanism 51F, which is a first-stage speed reduction mechanism; and a second speed reduction mechanism 52, which is a second-stage speed reduction mechanism.

[0126] As in Fig. As shown in Fig. 15, the planetary gear mechanism 51F includes: a motor shaft 43 as a sun gear 511F; a ring gear 512F disposed on the concentric circle of the sun gear 511 and serving as an output shaft; planetary gears 513F meshing with the sun gear 511F and the ring gear 512F; and planetary gear axes 514F as fixed shafts.

[0127] The ring gear 512F includes: an annular portion 5121 having an annular shape and tooth portions that mesh with the planetary gears 513F and are formed in the inner peripheral surface; a connecting portion 5122 connected to the annular portion 5121 and extending radially inward; and a cylindrical body portion 5123 connected to the connecting portion 5122 and extending along the axial direction of the crankshaft 30. The annular portion 5121, the connecting portion 5122, and the cylindrical body portion 5123 rotate integrally.

[0128] The rotational force of the motor 40 is transmitted via the cylindrical body portion 5123 to a first transmission gear 521 included in the second speed reduction mechanism 52. Note that a one-way clutch 53 is provided between the cylindrical body portion 5123 and the first transmission gear 521.

[0129] The planetary gear axles 514F are respectively fitted into recessed portions 3132 formed in the third split body 313F. Accordingly, the planetary gear axles 514F are non-rotatably fixed to the housing 31F. It is noted that in the Fig. 14 and Fig. 15, the planetary gear axles 514F are fixed to the third split body 313F. Alternatively, the planetary gear axles 514F may be fixed to the second split body 312F. The housing 31F is in the Fig. 14 and Fig. The example shown in Figure 15 is constructed from three divided bodies, but can instead be constructed from two divided bodies. [Eighth Embodiment]

[0130] Next, with reference to the Fig. 16 and Fig. 17 describes an eighth embodiment of a drive unit in the present invention. Fig. 16 is a sectional view of a drive unit 20G according to the eighth embodiment. Fig. 17 shows an enlarged view of the surroundings of an engine 40 in Fig. 16. In the following, the same symbols are assigned to the components common to those in the first embodiment, redundant description of these components is omitted, and differences from the first embodiment are mainly described.

[0131] As in Fig. 16, the drive unit 20G, similar to the drive unit 20 according to the first embodiment, includes: the motor 40 for applying rotational power to assist pedaling force to pedals 7; a housing 31 accommodating the motor 40; and a crankshaft 30 rotatably mounted on the housing 31.

[0132] The drive unit 20G further includes: a human power transmission body 61 mounted to rotate integrally with the crankshaft 30 and rotated by human power input; an output body 62 that outputs the rotational power of the engine 40; a gear 70 that outputs the rotational power of the output body 62; and a power transmission mechanism 50G that brakes the rotational power of the engine 40 and transmits the power to the gear 70 via the output body 62.

[0133] As in Fig. As shown in Fig. 17, the power transmission mechanism 50G is a parallel-shaft gear mechanism that meshes with the motor shaft 43 as the output shaft of the motor 40 and includes a first transmission gear 541 having a rotational axis parallel to the rotational axis of the motor shaft 43. The power transmission mechanism 50G is a mechanism that includes the first transmission gear 541, a wheel axle 542, and a second transmission gear 543, and transmits the rotational power of the motor 40 to the output body 62 via the first transmission gear 541, the wheel axle 542, and the second transmission gear 543.

[0134] The first transmission gear 541 is arranged in an opening portion of a rotor 42 in the radial direction. The first transmission gear 541 has tooth portions 541A that mesh with tooth portions 43A provided on the motor shaft 43. The rotor 42, the tooth portions 43A of the motor shaft 43, and the tooth portions 541A of the first transmission gear 541 are arranged at positions that overlap in the axial direction of the crankshaft 30. Accordingly, the size of the drive unit 20G can be reduced in the axial direction of the crankshaft 30. Grooves or splines are formed on the inner peripheral surface of the first transmission gear 541 to be attached to the gear axle 542. Note that the first transmission gear 541 may be insert molded onto the gear axle 542.

[0135] The wheel axle 542 is arranged along the axial direction of the crankshaft 30. The wheel axle 542 rotates integrally with the first transmission gear 541. Although there is no specific limitation on the length of the wheel axle 542, the length is, for example, between 5% and 50% of the length of the crankshaft 30 in the axial direction. Tooth portions 542A are formed on the right side of the wheel axle 542.

[0136] The second transmission gear 543 meshes with the toothed portions 542A formed on the right side of the gear axle 542. The rotational axis of the second transmission gear 543 is positioned concentrically on the rotational axis of the crankshaft 30.

[0137] A one-way clutch 53G is provided between the second transmission gear 543 and the output body 62. This means that the rotational power of the engine 40 output from the second transmission gear 543 is transmitted to the output body 62 via the one-way clutch 53G.

[0138] When the rotational force in the forward direction is applied to the second transmission gear 543, the one-way clutch 53G transmits the rotational force to the output body 62. When the rotational force in the direction opposite to the forward direction is applied to the second transmission gear 543, the one-way clutch 53G does not transmit the rotational force to the output body 62. When the rotational force in the forward direction is transmitted to the output body 62 via the human power transmission body 61, the one-way clutch 53G does not transmit the rotational force to the second transmission gear 543. [Ninth Embodiment]

[0139] Next, with reference to Fig. 18 describes a ninth embodiment of a drive unit in the present invention. Fig. 18 is a sectional view of a drive unit 20H according to the ninth embodiment. Hereinafter, the same symbols are assigned to the components common to those in the first embodiment, redundant descriptions of these components are omitted, and differences from the first embodiment will be mainly described.

[0140] As in Fig. 18, the drive unit 20H includes: a motor 40H for applying rotational power to assist pedaling force on pedals 7; a housing 31H accommodating the motor 40H; and a crankshaft 30 rotatably mounted on the housing 31H.

[0141] The drive unit 20H further includes: a human power transmission body 61H mounted to rotate integrally with the crankshaft 30 and rotated by human power input; an output body 62H that outputs the rotational power of the engine 40H; a gear 70 that outputs the rotational power of the output body 62H; and a power transmission mechanism 50H that brakes the rotational power of the engine 40H and transmits the power to the gear 70 via the output body 62H.

[0142] The motor 40H includes a stator 41H and a rotor 42H with an opening portion at the rotation center. In the present embodiment, the motor 40H does not include a motor shaft that rotates integrally with the rotor 42H. Note that the motor 40H may be an external rotor type motor or an axial gap type motor. Recessed portions 46H are formed in the motor 40H, into which planetary gear axles 504H, which are included in the power transmission mechanism 50H described later, are inserted.

[0143] Similar to the first embodiment, the housing 31H includes a first split body 311H constituting the right half of the housing 31H; and a second split body 312H constituting the left half of the housing 31H. The first split body 311H and the second split body 312H are joined together with a fastening member 34, such as a screw. Grooves or serrations are formed on the inner surface of the first split body 311H, which mesh with a first ring gear 5021H included in the power transmission mechanism 50H described later. Note that the first split body 311H and the first ring gear 5021H may be screwed together with a screw.

[0144] The power transmission mechanism 50H is a planetary gear mechanism including a ring gear 502H, planetary gears 503H, and planetary gear axles 504H. The power transmission mechanism 50H is a mechanism that decelerates the rotational power of the motor 40H and transmits the power to the gear 70 via the output member 62H. In the present embodiment, the planetary gear 503H is a stepped planetary gear comprising two gears with different outer diameters.

[0145] The ring gear 502H includes the first ring gear 5021H and a second ring gear 5022H. The first ring gear 5021H meshes with a large diameter portion of the planetary gear 503H, and the second ring gear 5022H meshes with a small diameter portion of the planetary gear 503H.

[0146] The first ring gear 5021H is attached to the inner surface of the first split body 311H constituting the housing 31H, and is thus non-rotatably fixed to the housing 31H. This means that the first ring gear 5021H functions as a fixed shaft of the planetary gear mechanism.

[0147] The second ring gear 5022H functions as the output shaft of the planetary gear mechanism, and the rotational force of the second ring gear 5022H is transmitted to the output body 62H via a one-way clutch 53H. The second ring gear 5022H is rotatably supported on the housing 31H by a bearing 320H.

[0148] As described above, the planetary gear 503H is a stepped planetary gear comprising two gears with different outer diameters. The planetary gear shafts 504H penetrate the centers of the respective planetary gears 503H and keep these planetary gears 503H freely rotatable. The left end of the planetary gear shaft 504H is fitted into the recessed portion 46H formed in the motor 40H. Accordingly, the planetary gear shaft 504H rotates integrally with the motor 40H. Note that the planetary gear 503H is not necessarily a stepped gear and may be formed from a single gear. In this case, the inner and outer diameters of the first ring gear 5021H and the second ring gear 5022H are substantially the same. However, by varying the modification coefficients in the gear data, the number of tooth sections of the gears can be changed.In this configuration, the shape of the planetary gear 503H is simplified, which improves the ease of assembly of the drive unit 20H.

[0149] The human power transmission body 61H is a cylindrical member extending along the axial direction of the crankshaft 30 and disposed on the outer peripheral portion of the crankshaft 30 in the housing 31H. The human power transmission body 61H rotates integrally with the crankshaft 30. In the present embodiment, the human power transmission body 61H is constructed of a single member. Similar to the first embodiment, it may be constructed of multiple members.

[0150] The driven body 62H is a cylindrical member extending along the axial direction of the crankshaft 30 and disposed on the outer peripheral portion of the crankshaft 30. The rotational axis of the driven body 62H is positioned concentrically on the rotational axis of the crankshaft 30. The driven body 62H is rotatably supported on the housing 31H by bearings 321H and 322H. The deceleration concept as in the drive unit 20H in the present embodiment tends to have low power transmission efficiency at a small number of revolutions and generates heat. Preferably, oil lubrication is appropriately employed to facilitate dissipation of the generated heat. Oil lubrication can reduce the friction coefficients of the tooth portions of the gears and simultaneously reduce heat generation.In addition, oil lubrication ensures that the oil adheres to the housing 31H, allowing heat to be efficiently dissipated from the housing 31H. Applying the oil to the motor 40H allows the motor 40H to efficiently dissipate heat. [Tenth Embodiment]

[0151] Next, with reference to Fig. 19 describes a tenth embodiment of a drive unit in the present invention. Fig. 19 is a sectional view of a drive unit 20J according to the tenth embodiment. Hereinafter, the same symbols are assigned to the components common to those in the first embodiment, redundant descriptions of these components are omitted, and differences from the first embodiment will be mainly described.

[0152] As in Fig. 19, the drive unit 20J includes: a motor 40J for applying rotational power to assist pedaling force to pedals 7; a housing 31J accommodating the motor 40J; and a crankshaft 30 rotatably mounted on the housing 31J.

[0153] The drive unit 20J further includes: an output body 62J that outputs the rotational power of the motor 40J; a gear or sprocket 70 that transmits the rotational power of the output body 62J; and a power transmission mechanism 50J that brakes the rotational power of the motor 40J and transmits the power to the gear 70 via the output body 62J. Note that the drive unit 20J does not include a human power transmission body, and the rotational power of the crankshaft 30 is directly transmitted to the output body 62J. The absence of the human power transmission body allows the components constituting the power transmission mechanism 50J to be arranged closer to the crankshaft 30 and facilitates the size reduction of the drive unit 20J.

[0154] The motor 40J includes a stator 41J and a rotor 42J with an opening portion at the center of rotation. In the present embodiment, the motor 40J does not include a motor shaft that rotates integrally with the rotor 42J. Note that the motor 40J may be an external rotor type motor or an axial gap type motor. Recessed portions 46J are formed in the motor 40J, into which planetary gear axles 504J are inserted, which are included in the power transmission mechanism 50J described later.

[0155] Similar to the first embodiment, the housing 31J includes a first split body 311J constituting the right half of the housing 31J; and a second split body 312J constituting the left half of the housing 31J. The first split body 311J and the second split body 312J are connected to each other by a fastening member 34, such as a bolt. Grooves or splines are formed on the inner surface of the first split body 311J, which mesh with a first ring gear 5021J included in the power transmission mechanism 50J described later. The first split body 311J includes a partition wall 3111J extending toward the crankshaft 30. The partition wall 3111J contacts a bearing 322J on its outer side in the radial direction and supports the bearing 322J. The partition wall 3111J may be constructed from a component (for example an insulator) of the stator 41J.

[0156] The interior of the housing 31J is divided by the partition wall 3111J. The motor 40J and the power transmission mechanism 50J are arranged in the space on the right side of the partition wall 3111J. A control board 81J is arranged in the space on the left side of the partition wall 3111J. Here, lubricating oil is stored in the space on the right side of the partition wall 3111J. Accordingly, the gears constituting the power transmission mechanism 50J are lubricated, and durability and smoothness are improved. Note that the space where the control board 81J is arranged is not provided with lubricating oil.

[0157] Preferably, an elastic member such as an O-ring is provided between the stator 41J and the housing 31J (first divided body 311J) to prevent leakage of the lubricating oil stored in the space on the right side of the partition wall 3111J. Preferably, an oil seal 37J is provided on the outer peripheral part of the crankshaft 30. Preferably, a bushing 38J made of metal such as iron is provided between the oil seal 37J and the motor 40J. This can prevent leakage of the lubricating oil stored in the space on the right side of the partition wall 3111J and reduce abrasion due to contact of a lip part of the oil seal 37J with the motor 40J.

[0158] The power transmission mechanism 50J is a planetary gear mechanism including a ring gear 502J, planetary gears 503J, and planetary gear axles 504J. The power transmission mechanism 50J is a mechanism that decelerates the rotational power of the motor 40J and transmits it to the gear 70 via the output member 62J. In the present embodiment, the planetary gear 503J is a stepped planetary gear comprising two gears with different outer diameters.

[0159] The ring gear 502J includes a first ring gear 5021J and a second ring gear 5022J. The first ring gear 5021J meshes with a large diameter portion of the planetary gear 503J, and the second ring gear 5022J meshes with a small diameter portion of the planetary gear 503J.

[0160] The first ring gear 5021J is mounted on the inner surface of the first split body 311J contained in the housing 31J, and is thus non-rotatably fixed to the housing 31J. This means that the first ring gear 5021J functions as a fixed shaft of the planetary gear mechanism.

[0161] On the other hand, the second ring gear 5022J functions as the output shaft of the planetary gear mechanism, and the rotational force of the second ring gear 5022J is transmitted to the output body 62J via a one-way clutch 53J. The second ring gear 5022J is rotatably supported on the housing 31J by a bearing 320J.

[0162] As described above, the planetary gear 503J is a stepped planetary gear comprising two gears with different outer diameters. The planetary gear axles 504J penetrate the centers of the respective planetary gears 503J and keep these planetary gears 503J freely rotatable. The left end of the planetary gear axle 504J is fitted into the recessed portion 46J formed in the motor 40J. Accordingly, the planetary gear axle 504J rotates integrally with the motor 40J. The bearing provided between the planetary gear 503J and the planetary gear axle 504J can be a ball bearing or a plain bearing.

[0163] The output body 62J is a cylindrical member extending along the axial direction of the crankshaft 30 and disposed on the outer peripheral portion of the crankshaft 30. The rotational axis of the output body 62J is positioned concentrically on the rotational axis of the crankshaft 30. As described above, in the present embodiment, no human power transmission body is provided. Accordingly, the rotational force of the crankshaft 30 is transmitted to the output body 62J via the one-way clutch 63J. The one-way clutch 63J also functions as a bearing and rotatably supports the output body 62J.

[0164] The drive unit 20J is provided with a plurality (for example, two to four) strain sensors 80J as torque detection sections. The strain sensors 80J are arranged on the outer side of the bearing 321J in the radial direction and measure a force exerted on the bearing 321J. The bearing 321J supports the crankshaft 30 on the opposite side of a location where the gear 70 is provided in the axial direction of the crankshaft 30 and is accordingly resistant to the influence of the chain tension. Thus, the strain sensors 80J can achieve correct detection. A rotation detection section 82J, which detects the rotation of the crankshaft 30, is arranged on the control board 81J.The rotation detecting portion 82J ​​includes, for example, a Hall element inside and is arranged at a position overlapping a magnet 86J provided on the outer peripheral portion of the crankshaft 30. The Hall element detects the change in the magnetic field of the magnet 86J due to the rotation of the crankshaft 30, thus enabling the measurement of the number of revolutions of the crankshaft 30. Note that the configuration of the rotation detecting portion 82J ​​is not limited to this. [Eleventh Embodiment]

[0165] Next, with reference to the Fig. 20 and Fig. 21 describes an eleventh embodiment of a drive unit in the present invention. Fig. 20 is a sectional view of a drive unit 120 according to the eleventh embodiment. Fig. 21 shows an enlarged view of the surroundings of an engine 140 in Fig. 20. In the following, the same symbols are assigned to the components common to those in the first embodiment, redundant description of these components is omitted, and differences from the first embodiment are mainly described.

[0166] As in Fig. 20, the drive unit 120 includes: the motor 140 for applying rotational power to assist pedaling force to pedals 7; a housing 131 accommodating the motor 140; and a crankshaft 130 rotatably mounted on the housing 131.

[0167] The drive unit 120 includes: a human power transmission body 161 mounted to rotate integrally with the crankshaft 130 and rotated by human power input; a first output body 162 that outputs the rotational power of the engine 140; and a second output body 163 that outputs the rotational power by human power input. The drive unit 120 includes: a first gear 171 that outputs the rotational power of the first output body 162; a second gear 172 that outputs the rotational power of the second output body 163; and a planetary gear mechanism 150 as a power transmission mechanism that decelerates the rotational power of the engine 140 and transmits the power to the first gear 171 via the first output body 162.This means that the first gear 171 outputs the rotational force of the motor 140 and the second gear 172 outputs the rotational force of the driving power of a human force.

[0168] The motor 140 includes a stator 141, a rotor 142, and a motor shaft 143 that rotates integrally with the rotor 142. In the present embodiment, the motor 140 is an internal rotor type motor. Note that the motor 140 may be an external rotor type motor.

[0169] The rotor 142 has an annular shape having a circular opening portion 144 (see Fig. 21) at the rotation center, and is arranged inside the stator 141. In the opening portion 144, a sun gear 1501, a ring gear 1502, planetary gears 1503, and planetary gear axles 1504, which are gears constituting the planetary gear mechanism 150, are arranged in the radial direction.

[0170] The rotor 142 and the motor shaft 143 are secured to each other by splines. Note that the rotor 142 and the motor shaft 143 may be secured by press fitting, shrink fitting, cooling fitting, or the like. When the rotor 142 and the motor shaft 143 are secured, an elastic member, such as a rubber member or urethane, may be provided between the rotor 142 and the motor shaft 143.

[0171] The motor shaft 143 is a cylindrical shaft-shaped member extending in the left-to-right direction and rotating integrally with the rotor 142. The motor shaft 143 is arranged such that its rotation axis extends along the axial direction of the crankshaft 130. The motor shaft 143 is rotatably supported by bearings 1320, 1321, and 1322 provided in the housing 131, so that it is rotatable with respect to the housing 131.

[0172] As in Fig. As shown in Figure 21, the motor shaft 143 is arranged such that the central rotational axis passes through the center of the ring gear 1502 included in the planetary gear mechanism 150 and penetrates the ring gear 1502. Tooth portions 143A are provided on the surface of the motor shaft 143, which mesh with the tooth portions 1503A of the planetary gears 1503 provided in the planetary gear mechanism 150. The motor shaft 143 constitutes the sun gear 1501 of the planetary gear mechanism 150.

[0173] It is noted that the size, shape, and the like of the motor 40 in the first embodiment can be appropriately adopted as the size, shape, and the like of the motor 140.

[0174] The housing 131 is a member that forms an outer shell of the drive unit 120 and houses the motor 140. The housing 131 is primarily made of metal, such as aluminum, stainless steel, or the like. Alternatively, a non-metallic material may also be used. There are no particular restrictions on the material of the housing 131.

[0175] The housing 131 includes a first split body 1311 constituting the right half of the housing 131; and a second split body 1312 constituting the left half of the housing 131. The first split body 1311 and the second split body 1312 are connected to each other with a fastening member 134 such as a screw. By joining the first split body 1311 and the second split body 1312 together, the hollow housing 131 is formed. Note that there are no particular restrictions on the size, shape, thickness, and the like of the housing 131. The space formed in the housing 131 may be closed or unclosed.

[0176] The first split body 1311 has a leftward protruding portion 13111. The ring gear 1502 included in the planetary gear mechanism 150 is attached to the protruding portion 13111.

[0177] A plurality of grooves 1312A are formed in the wall surface of the second split body 1312. This allows the area of ​​a part of the second split body 1312 that is in contact with the outside air to be increased. As a result, the temperature of the housing 131 can be lowered and the reliability of the drive unit 120 can be improved. Note that grooves may be formed in the wall surface of the first split body 1311 instead of or in addition to the wall surface of the second split body 1312.

[0178] Inside the housing 131 are the human power transmission body 161, a part of the first output body 162, a part of the second output body 163, and the planetary gear mechanism 150, in addition to the motor 140. The housing 131 is provided with through holes 1314 and 1315 through which the crankshaft 130 passes. Furthermore, the housing 131 is provided with a through hole 1316 through which the first output body 162 passes.

[0179] Note that in the present embodiment, the housing 131 is mounted on the outer side of a frame 2, but it may instead be housed within the frame 2, similar to the housing 31 in the first embodiment. When housing the housing 131 within the frame 2, a heat dissipation member that transfers heat from the housing 131 to the frame 2 may be interposed between the housing 131 and the frame 2.

[0180] The crankshaft 130 is a cylindrical element that is driven into rotation by human power. The crankshaft 130 can be constructed from a hollow element or a solid element.

[0181] Two crank arms (not shown) are provided at opposite ends of the crankshaft 130. The opposite ends of the crankshaft 130 protrude from the housing 131. The crankshaft 130 is rotatably supported on the housing 131 (frame 2) by bearings 1324 and 1325. The bearings 1324 and 1325 are formed, for example, from ball bearings.

[0182] The planetary gear mechanism 150 is a mechanism that decelerates the rotational force of the motor 140 and transmits the power to the first gear 171 via the first output member 162. In the present embodiment, the planetary gear mechanism 150 includes: the motor shaft 143 as the sun gear 1501; the ring gear 1502 arranged on a concentric circle of the sun gear 1501; the planetary gears 1503 that mesh with the sun gear 1501 and the ring gear 1502; the planetary gear axles 1504; and a planetary carrier 1505 as the output shaft.

[0183] The ring gear 1512 has a ring shape. The tooth portions 1502A are formed over the entire area of ​​the inner peripheral surface. The ring gear 1502 is non-rotatably fixed to the housing 131 by being attached to the protruding portion 13111 of the housing 131.

[0184] The planetary gear 1503 is a stepped planetary gear comprising two gears with different outer diameters. Tooth portions 1503A are formed over the entire circumference of each planetary gear 1503. The small-diameter portion of the planetary gear 1503 meshes with the ring gear 1502, and the large-diameter portion of the planetary gear 1503 meshes with the sun gear 1501. The use of the stepped planetary gear 1503 enables an increase in the reduction ratio of the planetary gear mechanism 150. Note that, similar to the first embodiment, the planetary gear 1503 is not necessarily the stepped planetary gear.

[0185] The planetary gear axes 1504 penetrate the centers of the respective planetary gears 1503 and hold these planetary gears 1503 in a freely rotatable manner. The planetary carrier 1505 supports the planetary gears 1503 to allow them to orbit. The rotational axis of the planetary carrier 1505 is positioned concentrically with the rotational axis of the sun gear 1501.

[0186] As in Fig. As shown in Fig. 21, the rotor 142 and the tooth portions 143A of the motor shaft 143, the tooth portions 1502A of the ring gear 1502, and the tooth portions 1503A of the planetary gears 1503 are arranged at overlapping positions in the axial direction of the crankshaft 130. Accordingly, the size of the drive unit 120 can be reduced in the axial direction of the crankshaft 130.

[0187] At least parts of the tooth portions 143A of the motor shaft 143, the tooth portions 1502A of the ring gear 1502, and the tooth portions 1503A of the planetary gears 1503 are arranged in the opening portion 144 of the rotor 142 in the radial direction. Accordingly, the drive unit 120 can be further reduced in size.

[0188] It is noted that the shapes, sizes, materials, and the like of the gears of the planetary gear mechanism 51 in the first embodiment can be appropriately adopted as the shapes, sizes, materials, and the like of the planetary gear 150.

[0189] The rotational force of the motor 140 output from the planetary gear mechanism 150 is transmitted to the first output member 162 via a one-way clutch 153. When the rotational force is applied in the forward direction to the planetary carrier 1505, the one-way clutch 153 transmits the rotational force to the first output member 162. When the rotational force is applied to the planetary carrier 1505 in the opposite direction to the forward direction, the one-way clutch 153 does not transmit the rotational force to the first output member 162.

[0190] The human power transmission body 161 is a cylindrical member extending along the axial direction of the crankshaft 130 and disposed at the outer peripheral portion of the crankshaft 130 in the housing 131. The human power transmission body 161 rotates integrally with the crankshaft 130. In the present embodiment, the human power transmission body 161 is divided into a first human power transmission body 1611 and a second human power transmission body 1612. Note that the human power transmission body 161 may be formed of a single member.

[0191] The first human power transmission body 1611 is coupled to the crankshaft 130. Grooves or splines are formed on the inner peripheral surface of the first human power transmission body 1611, which are attached to the crankshaft 130. Note that a missing tooth portion may be provided at a location where the first human power transmission body 1611 and the crankshaft 130 are joined. This allows positioning in the assembly direction and facilitates assembly. The first human power transmission body 1611 and the crankshaft 130 may be joined by press fitting or by a screw.

[0192] The second human power transmission body 1612 is arranged on the right side of the first human power transmission body 1611 in the axial direction of the crankshaft 130. The second human power transmission body 1612 is coupled to the first human power transmission body 1611 and transmits the rotational force to the second output body 163.

[0193] In the present embodiment, grooves or serrations are formed on the outer peripheral surface of the right end of the first human power transmission body 1611, which are attached to the inner peripheral surface of the left end of the second human power transmission body 1612. Accordingly, the first human power transmission body 1611 and the second human power transmission body 1612 are coupled to each other.

[0194] The first output member 162 is a shaft-shaped element extending along the axial direction of the crankshaft 130 and to which the rotational power of the motor 140 is transmitted. The rotational axis of the first output member 162 is positioned concentrically on the rotational axis of the motor shaft 143 (sun gear 1501). The rotational power of the motor 140 output by the planetary gear 150 is transmitted to the first output member 162 via the one-way clutch 153.

[0195] The length of the first output body 162 in the axial direction of the crankshaft 130 is shorter than the length of the crankshaft 130 and is, for example, between 10% and 50% of the length of the crankshaft 130 in the axial direction. The right end of the first output body 162 protrudes from the housing 131 through the through-bore 1316 in the housing 131. The first output body 162 is rotatably mounted in a bearing 1326 on the housing 131.

[0196] In a portion of the first output body 162 that protrudes from the housing 131, teeth or splines are formed, which are attached to the first gear 171. Accordingly, the first gear 171 rotates together with the first output body 162.

[0197] The second output body 163 is a cylindrical member extending along the axial direction of the crankshaft 130 and disposed on the outer peripheral portion of the crankshaft 130. The rotational axis of the second output body 163 is positioned concentrically on the rotational axis of the crankshaft 130.

[0198] Grooves or serrations are formed on the inner peripheral surface on the left end side of the second output body 163, which are attached to the outer peripheral portion of the second human power transmission body 1612. Accordingly, the second output body 163 rotates integrally with the second human power transmission body 1612. That is, the rotational force by the human power drive output from the human power transmission body 161 is transmitted to the second output body 163.

[0199] The length of the second output body 163 in the axial direction of the crankshaft 130 is shorter than the length of the crankshaft 130 and is, for example, between 10% and 50% of the length of the crankshaft 130 in the axial direction. The right end of the second output body 163 protrudes from the housing 131 through the through-bore 1314 in the housing 131. The second output body 163 is rotatably mounted on the housing 131 by the bearing 1324.

[0200] In a portion of the second output body 163 that protrudes from the housing 131, teeth or splines are formed that are intended to engage the second gear 172. Accordingly, the second gear 172 rotates integrally with the second output body 163.

[0201] The first gear 171 is arranged on the back side of the second gear 172. A chain (not shown) is wound around the first gear 171 and the second gear 172. The distance between the center of the first gear 171 and the center of the second gear 172 is, for example, at most 150 mm and may be less than or equal to 135 mm.

[0202] The second gear 172 has a larger outer diameter than the first gear 171. The number of teeth of the second gear 172 is greater than the number of teeth of the first gear 171. [Twelfth Embodiment]

[0203] Next, with reference to the Fig. 22 and Fig. 23, a twelfth embodiment of a drive unit in the present invention is described. Fig. 22 is a sectional view of a drive unit 220 according to the twelfth embodiment. Fig. 23 shows an enlarged view of the surroundings of an engine 240 in Fig. 22. In the following, the same symbols are assigned to the components common to those in the first embodiment, redundant description of these components is omitted, and differences from the first embodiment are mainly described.

[0204] As in Fig. 22, the drive unit 220 includes: the motor 240 for applying rotational power to assist pedaling force on pedals 7; a housing 231 forming part of an outer shell of the drive unit 220; and a crankshaft 230 rotatably mounted on the housing 231. As described in detail later, the rotational axis of the motor 240 and the rotational axis of the crankshaft 230 are concentrically arranged.

[0205] The drive unit 220 further includes: a pair of crank arms 6 having hollow structures; a human power transmission body 261 mounted to rotate integrally with the crankshaft 230 and rotated by a drive power of a human power; an output body 262 outputting the rotational power of the motor 240; a gear 270 outputting the rotational power of the output body 262; and a power transmission mechanism 250 decelerating the rotational power of the motor 240 and transmitting the power to the gear 270 via the output body 262.As will be described in detail later, the power transmission mechanism 250 is constructed of two stages of speed reduction mechanisms and includes: a first planetary gear mechanism (first power transmission mechanism) 251 which is a first-stage speed reduction mechanism; and a second planetary gear mechanism (second power transmission mechanism) 252 which is a second-stage speed reduction mechanism.

[0206] The crankshaft 230 is a cylindrical member having a hollow structure and opening at opposite ends. At least a portion of the power transmission mechanism 250 is disposed within the crankshaft 230. Accordingly, the drive unit 220 can be further reduced in size. The crankshaft 230 is provided with a through hole 2301 through which a planetary gear 2523, described later, protrudes. The crankshaft 230 is rotatably supported on the housing 231 (frame 2) by bearings 2320 and 2321. The bearings 2320 and 2321 are, for example, ball bearings.

[0207] The opposite ends of the crankshaft 230 protrude from the housing 231. A right crank arm 6A is connected to the right end of the crankshaft 230. The right crank arm 6A includes a base portion 6A1, which forms a main part of the right crank arm 6A and has an opening portion on the left side; and a cover portion 6A2, which blocks the opening portion. The base portion 6A1 and the cover portion 6A2 are joined together by a fastening member 6A3, such as a screw. By joining the base portion 6A1 and the cover portion 6A2, the hollow right crank arm 6A is formed.

[0208] The interior of the crankshaft 230 and the interior of the right crank arm 6A communicate with each other. The left end of the crankshaft 230 penetrates the left crank arm 6B, and an energy storage device 10 is attached to the left end of the crankshaft 230. Although described in detail later, the energy storage device 10 is configured to be attached to and detached from the left end of the crankshaft 230.

[0209] Gears or splines to be applied to a ring gear 2512 included in the first planetary gear mechanism 251 described later are formed in the inner peripheral surface of the crankshaft 230 at its right end side.

[0210] The housing 231 is a cylindrical member extending along the axial direction of the crankshaft 230 and covering the central portion of the crankshaft 230. The housing 231 is mounted, for example, in a bottom bracket (not shown). Parts of the human power transmission body 261 and the output body 262 are housed in the housing.

[0211] Gears or splines to be attached to a ring gear 2522 included in the second planetary gear mechanism 252 described later are formed in the inner peripheral surface of the housing 231 at its right end side.

[0212] As in Fig. As shown in Figure 23, the motor 240 includes a stator 241, a rotor 242, and a motor shaft 243 that rotates integrally with the rotor 242. In the present embodiment, the motor 240 is an internal rotor type motor. Note that the motor 240 may be an external rotor type motor or an axial gap type motor.

[0213] The motor 240 is housed in the crank arm 6 (right crank arm 6A) and the crankshaft 230. Specifically, the stator 241 and the rotor 242 are housed in the right crank arm 6A, and the motor shaft 243 is housed in the crankshaft 230. By housing the motor 240 in the crank arms 6 and the crankshaft 230, the size of the drive unit 220 can be reduced.

[0214] The rotor 242 has an annular shape with a circular opening portion 244 at the center of rotation and is disposed inside the stator 241. Radially disposed in the opening portion 244 are parts of a sun gear 2511, a ring gear 2512, planetary gears 2513, and a planetary gear axle 2514, which are gears constituting the first planetary gear mechanism 251.

[0215] The rotor 242 and the motor shaft 243 are secured to each other by splines. Note that the rotor 242 and the motor shaft 243 may be secured by press fitting, shrink fitting, cool fitting, or the like. When the rotor 242 and the motor shaft 243 are secured, an elastic member, such as a rubber or urethane member, may be provided between the rotor 242 and the motor shaft 243.

[0216] The motor shaft 243 is a cylindrical shaft-shaped member extending in the left-to-right direction and rotating integrally with the rotor 242. The motor shaft 243 is arranged such that its rotation axis extends along the axial direction of the crankshaft 230. The motor shaft 243 is rotatably supported in a bearing 2322 provided in the right crank arm 6A with respect to the crankshaft 230 and the right crank arm 6A.

[0217] The motor shaft 243 is arranged such that the central rotation axis passes through the center of the ring gear 2512 included in the planetary gear mechanism 251 and penetrates the ring gear 2512. Tooth portions 243A are provided on the surface of the motor shaft 243, which mesh with the tooth portions 2513A of the planetary gears 2513 provided in the first planetary gear mechanism 251. This means that the motor shaft 243 functions as the sun gear 2511 of the first planetary gear mechanism 251 and constitutes a gear of the first planetary gear mechanism 251.

[0218] It is noted that the size, shape, and the like of the motor 40 in the first embodiment can be appropriately adopted as the size, shape, and the like of the motor 240.

[0219] The power transmission mechanism 250 is a mechanism that decelerates the rotational force of the motor 240 and transmits the power to the gear 270 via the output member 262. In the present embodiment, the power transmission mechanism 250 consists of two stages of reduction mechanisms and includes: the first planetary gear mechanism 251, which is a first-stage speed reduction mechanism; and the second planetary gear mechanism 252, which is a second-stage speed reduction mechanism. Note that the power transmission mechanism 250 may be configured as a single-stage speed reduction mechanism.

[0220] As in Fig. As shown in Fig. 23, the first planetary gear mechanism 251 includes: the motor shaft 243 as the sun gear 2511; the ring gear 2512 disposed on the concentric circle of the sun gear 2511; the planet gears 2513 meshing with the sun gear 2511 and the ring gear 2512; the planet gear axles 2514; and a planet carrier 2515 as the output shaft.

[0221] The ring gear 2512 has an annular shape. Toothed portions 2512A are formed over the entire area of ​​the inner peripheral surface. The ring gear 2512 is non-rotatably fixed to the crankshaft 230 by being attached to the inner peripheral surface of the crankshaft 230.

[0222] The toothed portions 2513A are formed over the entire circumference of each planetary gear 2513. The planetary gear axles 2514 penetrate the centers of the respective planetary gears 2513 and keep these planetary gears 2513 freely rotatable. The planetary carrier 2515 supports the planetary gears 2513 so they can rotate. The rotational axis of the planetary carrier 2515 is positioned concentrically with the rotational axis of the sun gear 2511.

[0223] As in Fig. As shown in Fig. 23, the rotor 242 and the tooth portions 243A of the motor shaft 243, the tooth portions 2512A of the ring gear 2512, and the tooth portions 2513A of the planetary gears 2513 are arranged at overlapping positions in the axial direction of the crankshaft 230. Accordingly, the size of the drive unit 220 can be reduced in the axial direction of the crankshaft 230.

[0224] At least parts of the tooth portions 243A of the motor shaft 243, the tooth portions 2512A of the ring gear 2512, and the tooth portions 2513A of the planetary gears 2513 are arranged radially inside the opening portion 244 of the rotor 242. Accordingly, the drive unit 220 can be further reduced in size.

[0225] The rotational power of the motor 240 output from the first planetary gear mechanism 251 is transmitted to the second planetary gear mechanism 252 via a one-way clutch 253. When the rotational power is transmitted in the forward direction to the planetary carrier 2515, the one-way clutch 253 transmits the rotational power to the sun gear 2521 as the input shaft of the second planetary gear mechanism 252. When the rotational power is applied to the planetary carrier 2515 in the opposite direction to the forward direction, the one-way clutch 253 does not transmit the rotational power to the sun gear 2521.

[0226] As in Fig. As shown in Fig. 23, the second planetary gear mechanism 252 includes: the sun gear 2521 as an input shaft; the ring gear 2522 disposed on the concentric circle of the sun gear 2521; the planet gears 2523 meshing with the sun gear 2521 and the ring gear 2522; and planet gear axes 2524.

[0227] Regarding the sun gear 2521, the rotational axis of the sun gear 2521 is positioned concentrically on the rotational axis of the crankshaft 230. As described above, the rotational power of the engine 240 output from the first planetary gear mechanism 251 is transmitted to the sun gear 2521 via the one-way clutch 253. The sun gear 2521 is rotatably supported by the bearing 2323 provided on the left end side with respect to the crankshaft 230.

[0228] The ring gear 2522 has an annular shape. Toothed portions 2522A are formed over the entire area of ​​the inner peripheral surface. The ring gear 2522 is non-rotatably fixed to the housing 231 by being fitted to the inner peripheral surface of the housing 231.

[0229] The planetary gear 2523 is a stepped planetary gear comprising two gears with different outer diameters. The tooth portions 2523A are formed over the entire circumference of each planetary gear 2523. The small-diameter portion of the planetary gear 2523 meshes with the ring gear 2522, and the large-diameter portion of the planetary gear 2523 meshes with the sun gear 2521. The use of the stepped planetary gear 2523 enables an increase in the reduction ratio of the second planetary gear mechanism 252. Note that, similar to the first embodiment, the planetary gear 2523 is not necessarily the stepped planetary gear.

[0230] The planetary gear shafts 2524 penetrate the centers of the respective planetary gears 2523 and keep these planetary gears 2523 freely rotatable. The planetary gear shafts 2524 are inserted and fitted into through holes formed in the output body 262. Accordingly, the rotational power of the motor 240 output from the second planetary gear mechanism 252 is transmitted to the output body 262.

[0231] It is noted that the shapes, sizes, materials, and the like of the gears of the planetary gear 51 in the first embodiment can be appropriately adopted as the shapes, sizes, materials, and the like of the gears of the first planetary gear 251 and the second planetary gear 252.

[0232] As in Fig. As shown in Fig. 22, the human power transmission body 261 is a cylindrical member extending along the axial direction of the crankshaft 230 and disposed at the outer peripheral portion of the crankshaft 230 in the housing 231. The human power transmission body 261 rotates integrally with the crankshaft 230. In the present embodiment, the human power transmission body 261 is constructed of a single member. Similar to the first embodiment, it may be constructed of multiple members.

[0233] The human power transmission body 261 is coupled to the crankshaft 230. Grooves or splines are formed on the inner peripheral surface of the human power transmission body 261 at its left end side, and are attached to the crankshaft 230. The human power transmission body 261 and the crankshaft 230 can be joined by press fitting or with a screw. The length of the human power transmission body 261 in the axial direction of the crankshaft 230 is shorter than the length of the crankshaft 230, and is, for example, between 10% and 50% of the length of the crankshaft 230 in the axial direction. Note that the power unit 220 does not necessarily include the human power transmission body 261.In this case, the output body 262 and the crankshaft 230 are engaged with each other via splines or the like, and the rotational force of the crankshaft 230 is transmitted to the output body 262. In the case without the human power transmission body 261, the load on the crankshaft 230 can be detected by a strain sensor attached to the outer peripheral surface of the crankshaft 230, and thus the human power input torque can be detected. The human power input torque can be detected by detecting the force on the outer gear side of a bearing 2321 by the strain sensor. This eliminates the need for the human power transmission body 261 and further facilitates the size and weight reduction of the power unit 220.

[0234] On the outer peripheral portion on the right end side of the human power transmission body 261, tooth portions are provided, which mesh with the tooth portions provided on the inner peripheral surface of the output body 262. Accordingly, the rotational force by the driving power of a human power is transmitted to the output body 262 via the power transmission body 261. Note that a one-way clutch may be provided between the power transmission body 261 and the output body 262.

[0235] The output body 262 is a cylindrical member that extends along the axial direction of the crankshaft 230 and is arranged on the outer peripheral portion of the crankshaft 230. The rotational axis of the output body 262 is positioned concentrically on the rotational axis of the crankshaft 230.

[0236] The length of the output body 262 in the axial direction of the crankshaft 230 is shorter than the length of the crankshaft 230 and is, for example, between 10% and 50% of the length of the crankshaft 230 in the axial direction. The output body 262 is rotatably mounted on the housing 231 by the bearing 2320.

[0237] The right end of the output body 262 protrudes from the housing 231 through a through hole 2311 in the housing 231. A portion of the output body 262 that protrudes from the housing 231 is formed with teeth or splines that are attached to the gear 270. Accordingly, the gear 270 rotates integrally with the output body 262.

[0238] Note that the human power transmission body 261 and the driven body 262 are provided separately in the present embodiment, but they may be configured integrally. For example, the human power transmission body 261 is not necessarily provided, and only the driven body 262 may be provided. In this case, by transmitting the rotational force of the crankshaft 230 to the driven body 262 by the driving power of human power, the power-assisted bicycle 1 is moved forward.

[0239] A one-way clutch may be arranged between the output body 262 and the gear 270. When the rotational force is applied to the output body 262 in a forward direction, the one-way clutch transfers the rotational force to the gear 270. When the rotational force is applied to the output body 262 in the opposite direction to the forward direction, the one-way clutch does not transfer the rotational force to the gear 270.

[0240] As in Fig. As shown in Fig. 22, the drive unit 220 includes torque detecting sections 280 for detecting the torque of the driving power of a human force; and a control board 281 on which a control device (not shown) is arranged for controlling and / or regulating the output of the motor 240 in response to the detected torque and for achieving an appropriate power assist function. The drive unit 220 further includes a rotation detecting section 282 for detecting the rotation of the crankshaft 230.

[0241] The torque detecting sections 280 are provided on the outer peripheral portion of the human power transmitting body 261 and detect the strain applied to the human power transmitting body 261. For example, a strain sensor that detects physical strain can be used as each torque detecting section 280. For example, a scheme can be used in which a paint that emits light in response to a mechanical stimulus is applied to the outer peripheral portion of the human power transmitting body 261, and the light is detected by an optical sensor.

[0242] In the case of torque detection using the strain sensor, the drive unit 220 includes a total of two torque detecting sections 280, one at each of the circumferentially opposite positions on the outer peripheral portion of the human power transmission body 261. Note that the number of torque detecting sections 280 provided on the outer peripheral portion of the human power transmission body 261 may be as few as one or three or more. The installation positions of the torque detecting sections 280 are not limited to the outer peripheral portion of the human power transmission body 261 and may be, for example, on the outer peripheral portion of the crankshaft 230.

[0243] The control device is arranged on the control board 281 and controls and / or regulates the rotation of the motor 240 based on the torque detected by each torque detecting section 280. The control device controls and / or regulates the rotation of the motor 240 based on detection information from the rotation detecting section 282. A conventional, publicly known configuration may be used as the configuration of the control device. The torque detecting sections 280 may communicate with the control device via signal lines or wireless signals. Note that the control board 281 on which the control device is arranged may be arranged adjacent to the motor 240, as shown in FIG. Fig. 22. For example, on the control board 281 disposed adjacent to the motor 240, a rotor rotation detecting section may be provided to detect the rotation of the rotor 242.

[0244] In the present embodiment, the control board 281 is housed in the right crank arm 6A. This means that the control board 281 rotates together with the crankshaft 230. The control board 281 is housed in the right crank arm 6A, which can enable a reduction in the size of the drive unit 220.

[0245] The rotation detection section 282 detects the number of revolutions of the crankshaft 230. The rotation detection section 282 is, for example, an inertial sensor such as an acceleration sensor or a gyroscope sensor. Note that the configuration of the rotation detector 282 is not limited to these.

[0246] In the present embodiment, at least a part of the rotation detecting section 282 is disposed on the control board 281. This means that at least a part of the rotation detecting section 282 rotates integrally with the crankshaft 230. Accordingly, a reduction in the size of the power unit 220 can be facilitated. Note that at least a part of the rotation detecting section 282 may be disposed on the crankshaft 230 or the human power transmission body 261.

[0247] The rotation detecting section 282 can communicate with the control device using signal lines, and preferably using radio signals. This eliminates the space required for accommodating a signal line connecting the rotation detecting section 282 and the control device, and facilitates the reduction in size of the drive unit 220.

[0248] As in Fig. As shown in Figure 22, the energy storage device 10 is mounted on the left end of the crankshaft 230. This means that the energy storage device 10 rotates integrally with the crankshaft 230.

[0249] The energy storage device 10 includes a case body 10A that houses a storage battery 10C and is arranged outside the crankshaft 230; and a connector 10B connected to the case body 10A. The case body 10A and the connector 10B are connected to each other by a fastening member 10D, such as a screw. The case body 10A has a recessed portion 10E into which the crankshaft 230 is fitted. A control board 10H that controls and / or regulates the energy storage device 10 is provided in the case body 10A.

[0250] The energy storage device 10 is configured to be attachable to and detachable from the crankshaft 230. Specifically, a locking mechanism 10F is provided on the outer side of the housing body 10A in the radial direction of the rotational axis of the crankshaft 230. When the locking mechanism 10F is unlocked, a protruding portion 10G retracts from an engagement location and is released from the recessed portion 10E, and the energy storage device 10 can be removed from the crankshaft 230. By locking the locking mechanism 10F in a state where the crankshaft 230 is fitted into the recessed portion 10E, the protruding portion 10G is fitted to the engagement location, the crankshaft 230 is fixed by the recessed portion 10E, and the energy storage device 10 is fixed to the crankshaft 230.It should be noted that no specific limitation is imposed on the configuration of the locking mechanism 10F as long as the configuration allows the energy storage device 10 to be attached to and detached from the crankshaft 230. For example, the locking mechanism 10F may be arranged in the axial direction of the crankshaft 230.

[0251] The connector 10B is arranged in the crankshaft 230 and is configured to be inserted into the left end of an internal connector 284 in the crankshaft 230. It is configured such that the outer diameter of the connector 10B is smaller than the inner diameter of the crankshaft 230. A cable 283, which supplies power to the components of the drive unit 220, such as the motor 240, is connected to the right end of the internal connector 284. In the example in Fig.22, the cable 283 runs through the crankshaft 230 and is connected to the control or regulating board 281, which is arranged in the right crank arm 6A.

[0252] It should be noted that the method for supplying power to the components constituting the drive unit 220 is not limited to this. For example, the energy storage device 10 may be mounted on the frame 2, and electric power may be supplied to the drive unit 220 via a slip ring. The drive unit 220 includes, for example, an electric power receiving portion that rotates integrally with the crankshaft 230; and an electric power supplying portion that is fixed to the frame 2 and has a brush for supplying electric power to the electric power supplying portion. The electric power receiving portion is provided with the slip ring. The distal end portion of the brush is in contact with the slip ring and is displaced by the rotation thereof, and electric power is supplied from the brush to the slip ring.It is noted that the method of supplying electric power using the slip ring is not limited to the form described above.

[0253] It should be noted that the configuration of each of the above-described embodiments can be appropriately changed within a range without altering the advantage of the present invention. For example, in each of the embodiments, the power-assisted bicycle 1 is described, which is provided with the crank arms 6 at the opposite ends of the crankshafts 30, 130, 230. Alternatively, this may also apply to an electric vehicle without the crank arms 6 at the opposite ends of the crankshafts 30, 130, 230. This means that the vehicle may be an electric vehicle that moves forward not by the driving power of a human force, but by the rotational power of the motor. LIST OF REFERENCE SYMBOLS 1 power-assisted bicycle 2 frames 2A steering head 2B front fork 2C top tube 2D down tube 2E seat tube 2F seat stays 2G chainstays 3A front wheel 3B rear wheel 4 handlebars 5 Saddle 6 crank arm 6A right crank arm 6A1 Base Section 6A2 cover section 6A3 Fastening element 6B left crank arm 7 pedals 8 Chain 10 Device for storing energy 10A housing body 10B connector 10C storage battery 10D fastener 10E in-depth section 10F locking mechanism 10G preceding section 10H control or regulation board 11 Rear wheel sprocket or rear wheel sprocket 20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 120, 220 drive unit 30, 130, 230 crankshaft 31, 31E, 31F, 13 1, 231 Housing 33 Heat dissipation element 34, 134, 341, 342 fastening element 35 Heat dissipation element 36 projection element 40, 40A, 40D, 140, 240 engine 41, 41A, 41D, 141, 241 Stator 42, 42A, 42D, 142, 242 rotors 43, 43D, 143, 243 motor shaft 43A, 143A, 243A, 512A, 513A, 541A, 542A, 1502A, 1503A, 2512A, 2513A, 2522A, 2523A tooth sections 44, 144, 244 opening section 50, 50B, 50C, 50F, 50G, 250 power transmission mechanism 51, 51B, 51F , 150, 251 planetary gear 52 second speed reduction mechanism 53, 53G, 63, 153, 253 freewheel clutch 61, 161, 162 Bodies for the transmission of a human force 62, 262 output body 70, 270 gear or sprocket 80, 280 Section for detecting a torque 81, 281 Control or regulation board 82, 282 Section for detecting a rotation 83, 283 cables 84 connectors 85 Section for detecting rotation of a rotor 86, 86J magnet 162 first output body 163 second output body 171 first gear or sprocket 172 second gear or sprocket 251 first planetary gear mechanism 252 second planetary gear mechanism 284 internal connector 311, 311E, 311F, 1311 first divided body 312, 312E, 312F, 1312 second split body 313E, 313F third split body 314, 315, 1314, 1315, 1316, 2301, 2311 through hole 320, 321, 322, 323, 324, 325, 326, 327, 1329, 1321, 1322, 1324, 1325, 1326, 2320, 2321, 2322, 2323 bearings; 511, 511F, 1501, 2511, 2521 sun gear 512, 512F, 1502, 2512, 2522 ring gear 513, 513F, 1503, 2513, 2523 planetary gear 514, 514F, 1504, 2514, 2524 planetary gear axle 515, 515B, 515C, 515F, 1505, 25 15 planet carrier 516 output element 521, 541 first transmission gear or transmission gear 522, 543 second transmission gear or transmission gear 542 wheel axle 611, 1611 first body for transmitting a human force 612, 1612 second body for the transmission of a human force 841 first section 842 second section 1312A grooves 3111, 3131, 13111 previous section 3112, 3132 in-depth section 5121 annular section 5122 connecting section 5123 cylindrical body section 5151 hollow section 5161 preceding section 5162 small diameter section QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 7246001 B [0002, 0003]

Claims

[1] Drive unit for use in an electric vehicle, comprising: a motor having a rotor with an opening portion at a rotation center; a housing that houses the motor; a crankshaft rotatably mounted on the housing; a gear that delivers a rotational force from the engine; and a power transmission mechanism that slows down or accelerates the rotational force of the motor to transmit the power to the gear, wherein the power transmission mechanism comprises at least one gear wheel provided with toothed portions on one surface, the rotor and the tooth portions are arranged at positions that overlap in an axial direction of the crankshaft, and at least a part of the gear wheel is arranged within the opening section. [2] Drive unit for use in an electric vehicle, comprising: a motor having a rotor with an opening portion at a rotation center; a housing that houses the motor; a crankshaft rotatably mounted on the housing and rotatable by a driving power of a human force; a first gear that outputs a rotational force of the motor; a second gear wheel that delivers a rotational force of the driving power of a human force; and a power transmission mechanism that slows down or accelerates the rotational force of the engine to transmit the power to the first gear, wherein the power transmission mechanism comprises at least one gear wheel provided with toothed portions on one surface, the rotor and the tooth portions are arranged at positions that overlap in an axial direction of the crankshaft, and at least a part of the gear wheel is arranged within the opening section. [3] Drive unit according to claim 1 or 2, wherein the crankshaft is rotatable by a driving power of a human force, and the drive unit further comprises: a torque detecting section that detects the driving power of a human force applied to the crankshaft; and a control device that controls and / or regulates the rotation of the motor based on detection information of the torque detecting section. [4] A drive unit according to claim 1 or 2, wherein the power transmission mechanism comprises a planetary gear mechanism including planetary gears, planetary gear axles and a planetary carrier. [5] A drive unit according to claim 4, wherein the gears of the planetary gear mechanism comprise a helical gear. [6] The drive unit according to claim 4, wherein the planetary gear mechanism further comprises a ring gear, and the ring gear is non-rotatably mounted to the housing. [7] The drive unit according to claim 4, wherein the planetary gear mechanism further comprises a sun gear, and the sun gear is non-rotatably mounted on the housing. [8] Drive unit according to claim 4, wherein the planet carrier is non-rotatably attached to the housing. [9] A drive unit according to claim 1 or 2, wherein the power transmission mechanism is a mechanism that slows down or accelerates the rotational force of the engine in multiple stages, and comprises: a first power transmission mechanism; and a second power transmission mechanism located on a transmission path on a side of a subsequent stage of the first power transmission mechanism and to which a rotational force of the first power transmission mechanism is transmitted, the power transmission mechanism further comprises: a first bearing that rotatably supports gears included in the second power transmission mechanism on the housing; and a one-way clutch provided between the first power transmission mechanism and the second power transmission mechanism, and the first bearing and the one-way clutch are arranged at positions that overlap in the axial direction of the crankshaft. [10] Drive unit according to claim 1 or 2, wherein the power transmission mechanism slows down or accelerates the rotational force of the engine in several stages, the power transmission mechanism has: a first power transmission mechanism comprising a sun gear, planetary gears, a planetary carrier, and a ring gear; and a second power transmission mechanism located on a transmission path side of a subsequent stage of the first power transmission mechanism and to which a rotational force of the first power transmission mechanism is transmitted, a second bearing rotatably supporting the sun gear on the housing is provided at one end of the sun gear in the housing, the second bearing and the second power transmission mechanism are arranged at positions overlapping in the axial direction of the crankshaft, and a rotational axis of the rotor and a rotational axis of the crankshaft are each arranged on different axes. [11] Drive unit according to claim 5, wherein the power transmission mechanism comprises a cylindrical output element meshing with an output shaft of the planetary gear, the output element has a small diameter portion which is designed to have a smaller diameter than other portions, and a third bearing, which rotatably supports the output member on the housing, is arranged on an outer side of the small diameter portion in the radial direction. [12] The drive unit according to claim 1 or 2, wherein the power transmission mechanism comprises a parallel shaft gear mechanism having a gear meshing with a motor shaft as an output shaft of the motor and having a rotation axis arranged parallel to a rotation axis of the motor shaft. [13] Drive unit according to claim 1 or 2, further comprising a control board on which a control device is arranged which controls and / or regulates the rotation of the motor, the control board being connected to the motor. [14] Drive unit according to claim 1 or 2, wherein the motor has a stator, and the stator has an outer diameter equal to or less than 100 mm. [15] Drive unit according to claim 1 or 2, wherein the motor has a stator and the stator has an outer diameter equal to or less than 90 mm. [16] Drive unit according to claim 1 or 2, wherein the rotor has an inner diameter equal to or less than 30 mm. [17] Drive unit according to claim 1 or 2, wherein the rotor has an inner diameter equal to or greater than 40 mm. [18] The drive unit according to claim 3, further comprising a rotation detecting section that detects rotation of the crankshaft, wherein at least a part of the rotation detecting section is arranged on a circuit board on which the control or regulating device is arranged. [19] The drive unit according to claim 18, wherein the torque detecting portion is disposed on the circuit board. [20] Drive unit according to claim 3, wherein a cable extending from an outer side of the drive unit is connected via a connector to the circuit board on which the control device is arranged, and the connector has a first portion extending in a substantially normal direction of a surface of the board and a second portion extending in a direction inclined from the substantially normal direction of the surface of the board. [21] Drive unit according to claim 3, wherein the torque detecting portion rotates integrally with the crankshaft, and the torque detecting section and the control or regulating device communicate with each other via a wireless signal. [22] The drive unit according to claim 1 or 2, wherein the housing is fixed to a frame of the electric vehicle, and the housing has a heat dissipation portion that transfers heat to the frame. [23] A drive unit according to claim 1 or 2, wherein an interior space of the housing is divided into at least two spaces, and a space, which is one of the spaces and in which the power transmission mechanism is arranged, accommodates lubricating oil. [24] Drive unit for use in an electric vehicle, comprising: a motor having a rotor with an opening portion at a rotation center; a housing; a crankshaft rotatably mounted on the housing; a gear that delivers a rotational force from the engine; and a power transmission mechanism that slows down or accelerates the rotational force of the engine to transmit the power to the gear, wherein the power transmission mechanism comprises at least one gear wheel provided with toothed portions on one surface, the rotor and the tooth portions are arranged at positions that overlap in an axial direction of the crankshaft, and an axis of rotation of the rotor and an axis of rotation of the crankshaft are arranged concentrically. [25] Drive unit according to claim 24, wherein the crankshaft has a hollow structure and at least part of the power transmission mechanism is accommodated in the crankshaft. [26] The drive unit of claim 24, further comprising an energy storage device that supplies electrical energy to the motor, the energy storage device rotating integrally with the crankshaft. [27] The drive unit of claim 24, further comprising a one-way clutch disposed between the crankshaft and the power transmission mechanism, the one-way clutch receiving a radial load. [28] A drive unit according to claim 27, wherein the one-way clutch is arranged closer to the gear in the axial direction of the crankshaft than a central portion of the crankshaft in the axial direction. [29] Drive unit for use in an electric vehicle, comprising: an engine; a housing that houses the motor; a crankshaft rotatably mounted on the housing; a gear that delivers a rotational force from the engine; and a power transmission mechanism that slows down or accelerates the rotational force of the motor to transmit the power to the gear; and a rotation detecting section that detects the rotation of the crankshaft or a member rotating integrally with the crankshaft, and wherein the rotation detecting portion rotates integrally with the crankshaft. [30] The drive unit according to claim 29, further comprising a control device that controls and / or regulates rotation of the motor based on detection information of the rotation detecting section, wherein the rotation detecting section and the control device communicate with each other by a wireless signal. [31] The drive unit according to claim 30, wherein the rotation detecting section and the control device are arranged on the same board. [32] Drive unit for use in an electric vehicle, comprising: an engine; a housing that houses the motor; a crankshaft rotatably mounted on the housing; a gear that delivers a rotational force from the engine; and a power transmission mechanism that slows down or accelerates the rotational force of the engine to transmit the power to the gear, where the engine has: a motor shaft which is an output shaft; a stator attached to the housing; and a rotor attached to the motor shaft and having a magnet, wherein the rotor is arranged to face the stator in a direction along a rotational axis of the motor shaft, the power transmission mechanism comprises at least one gear wheel provided with toothed portions on one surface, and the stator and the tooth portions are arranged at positions overlapping in an axial direction of the crankshaft. [33] Drive unit according to claim 32, wherein the rotor is arranged only on one side of the stator in the direction along the axis of rotation of the motor shaft. [34] The drive unit of claim 32, further comprising a plurality of bearings rotatably supporting the motor shaft on the housing, the plurality of bearings being arranged separately in the direction along the rotational axis of the motor shaft. [35] A drive unit according to any one of claims 1, 2, 24, 29 and 32, further comprising a bearing that rotatably supports the crankshaft and a section for detecting a torque of a force applied to the bearing. [36] An electric vehicle comprising the drive unit according to any one of claims 1, 2, 24, 29 and 32.

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