bicycle drive unit

Abstract

Bicycle drive unit (40) comprising: a planetary gear mechanism (46) comprising a sun gear (54), a ring gear (56) which is / will be arranged coaxially with the sun gear (54), planet gears (58) which are located between the sun gear (54) and the ring gear (56), and a carrier (62) which rotatably holds the planet gears (58) and receives a rotation of a crankshaft (42), wherein the crankshaft (42) and the carrier (62) are / will be connected, a first motor (48) configured to transmit a torque to the support (62), wherein the first motor (48) is connected to the support (62); a second motor (50) configured to transmit torque to the sun gear (54) and to control rotation of the sun gear (54); a housing (44) that accommodates at least the planetary gear mechanism (46); and a one-way coupling (66; 68) located between the sun gear (54) and the housing (44), wherein the one-way coupling (66; 68) allows the sun gear (54) to rotate relative to the housing (44) in only one direction.

Description

TECHNICAL AREA

[0001] The present invention relates to a bicycle drive unit. BACKGROUND

[0002] Patent document 1 describes a bicycle comprising a continuously variable automatic transmission device of the prior art. The continuously variable automatic transmission device comprises a planetary gear mechanism coupled to a crankshaft and a motor that controls the rotation of the elements comprising the planetary gear mechanism. STATE OF THE ART DOCUMENTS PATENT DOCUMENTS

[0003] Patent Document 1: The Japanese patent publication JP H10 - 203 466 A describes a continuously variable transmission consisting of a differential gear of the planetary gear type.

[0004] DE 60 2004 008 288 T2 describes a hub with a substantially cylindrical, hollow hub part which is arranged to rotate about its axis and in the interior of which a transmission system with a variable ratio is housed.

[0005] WO 2013 / 160 477 A1 describes a drive train for a pedal vehicle comprising a first motor and a second motor, wherein the second motor is engaged with the axle of the pedal crank and the first motor is connected to a planetary gear.

[0006] The subsequently published document WO 2016 / 034 574 A1 describes a drive train for a pedal vehicle, comprising a first and a second motor as well as a planetary gear with a planet carrier, a ring gear and a sun gear.

[0007] WO 2014 / 081 105 A1 describes an input synthesis gear system comprising a first power source for generating a torque; a second power source for generating a torque, a third power source for generating a torque and a gear section for generating a synthesized output power from the inputs of the first power source to the third power source.

[0008] MÜLLER, Herbert W.: The Planetary Gears. Design and Versatile Applications. Second revised and expanded edition. Berlin; Heidelberg; New York; Barcelona; Budapest; Hong Kong; London; Milan; Paris; Santa Clara; Singapore; Tokyo: Springer, 1998. pp. 245–251. ISBN 978-3-642-63698-1 describes a wide variety of planetary gear designs. SUMMARY OF THE INVENTION

[0009] The continuously variable automatic transmission device of patent document 1 is designed to change the gear ratio continuously. However, the same motor is used to change the gear ratio of the planetary gear mechanism and to transmit torque to the planetary gear mechanism. Consequently, the gear ratio and the torque cannot be changed independently.

[0010] The inventor of the present invention has developed a bicycle drive unit that allows for control according to the riding conditions. It is an object of the present invention to provide a bicycle drive unit that performs control according to the riding conditions.

[0011] In a first aspect of the present invention, a bicycle drive unit comprises a planetary gear mechanism, a first motor, and a second motor. The planetary gear mechanism includes a sun gear, a ring gear which is / will be arranged coaxially with the sun gear, planet gears located between the sun gear and the ring gear, and a carrier which rotatably holds the planet gears and receives / will receive the rotation of a crankshaft. The crankshaft and the carrier are / will be connected. The first motor is configured to transmit torque to the carrier. The first motor is connected to the first carrier. The second motor is configured to transmit torque to the sun gear and to control the rotation of the sun gear.The bicycle drive unit further comprises a housing that accommodates at least the planetary gear mechanism and a one-way coupling located between the sun gear and the housing, the one-way coupling allowing the sun gear to rotate relative to the housing in only one direction.

[0012] In several examples, the bicycle drive unit further includes an output section that is coupled to a front sprocket. The ring gear is connected to the output section. One embodiment of the bicycle drive unit further includes the crankshaft.

[0013] In several examples, the carrier is arranged coaxially with the crankshaft. In several examples, the sun gear is arranged coaxially with the crankshaft.

[0014] In several examples, the second motor is arranged coaxially with the crankshaft. In several examples, the sun gear is integrally formed with an output shaft of the second motor.

[0015] In several examples, a rotating shaft of the first motor is separated from the crankshaft in one radial direction. Several examples also include a housing that accommodates at least the planetary gear mechanism. A one-way clutch is located between the sun gear and the housing. The one-way clutch allows the sun gear to rotate relative to the housing in only one direction.

[0016] In several examples, the housing includes a support located in a space extending between an inner circumference of the sun gear and the crankshaft. The one-way clutch is situated between the sun gear and the support.

[0017] In several examples, the bicycle drive unit further includes a one-way clutch located between the crankshaft or carrier and the ring gear or output section. The one-way clutch allows the output section to rotate in only one direction relative to the crankshaft.

[0018] In several examples, at least one of the first motors and one of the second motors are housed within the casing. In several examples, the second motor modifies the gear ratio of the planetary gear mechanism, which includes at least a range of 1.2 to 1.5.

[0019] In several examples, the second motor changes the gear ratio of the planetary gear mechanism in a range from 0.2 to 3.0. In several examples, the bicycle drive unit further includes a controller that controls the first and second motors. IMPACT OF THE INVENTION

[0020] The present invention provides a bicycle drive unit that allows for control according to the riding conditions. Other aspects and advantages of the present invention will become apparent from the following description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a side view of a bicycle including an embodiment of a bicycle drive unit. Fig. Figure 2 shows a cross-sectional view of the bicycle drive unit. Fig. 1. Fig. Figure 3 is a schematic diagram illustrating the direction of rotation of each element in a planetary gear mechanism, as shown in Figure 3. Fig. 2. Fig. Figure 4 is a schematic diagram of the bicycle drive unit shown in Fig. 2. Fig. Figure 5 is a schematic diagram depicting a bicycle drive unit not according to the invention. Fig. Figure 6 is a schematic diagram depicting a first modified example of a bicycle drive unit. Fig. Figure 7 is a schematic diagram depicting a second modified example of a bicycle drive unit. Fig. Figure 8 is a schematic diagram depicting a third modified example of a bicycle drive unit. Fig. Figure 9 is a schematic diagram illustrating a fourth modified example of a bicycle drive unit not according to the invention. Fig. Figure 10 is a schematic diagram illustrating a fifth modified example of a bicycle drive unit not according to the invention. Fig. Figure 11 is a schematic diagram illustrating a sixth modified example of a bicycle drive unit not according to the invention. Fig. Figure 12 is a schematic diagram illustrating a seventh modified example of a bicycle drive unit not according to the invention. Fig. Figure 13 is a schematic diagram illustrating an eighth modified example of a bicycle drive unit not according to the invention. Fig. Figure 14 is a schematic diagram illustrating a ninth modified example of a bicycle drive unit not according to the invention. Fig. Figure 15 is a schematic diagram illustrating a tenth modified example of a bicycle drive unit not according to the invention. Fig. Figure 16 is a schematic diagram illustrating an eleventh modified example of a bicycle drive unit not according to the invention. FORMS OF EXECUTION OF THE INVENTION

[0021] The structure of a bicycle including a bicycle drive unit is now described with reference to Fig. 1 described. A bicycle 10 includes a frame 12, a handlebar 14, a front wheel 16, a rear wheel 18, a drive mechanism 20, a battery unit 22 and a drive unit 40.

[0022] The drive mechanism 20 comprises left and right crank arms 24, left and right pedals 26, a front sprocket 30, a rear sprocket 32, and a chain 34. The left and right crank arms 24 are rotatably coupled to the frame 12 by a crankshaft 42 of the drive unit 40. The pedals 26 are coupled to the crank arms 24 and are rotatable with respect to the pedal shafts 28.

[0023] The front sprocket 30 is connected to an output section 64 (referring to Fig. 2) the drive unit 40. The front sprocket 30 is coaxial with the crankshaft 42. The rear sprocket 32 ​​is rotatably coupled to an axis 18a of the rear wheel 18. The rear sprocket 32 ​​is coupled to the rear wheel 18 by a one-way clutch. The chain 34 is wound around the front sprocket 30 and the rear sprocket 32. The application of human power rotates the crank arms 24. As a result, the front sprocket 30, the chain 34, and the rear sprocket 32 ​​rotate the rear wheel 18.

[0024] The battery unit 22 includes a battery 36 and a battery holder 38, which allows the battery 36 to be attached to the frame 12 in a detachable manner. The battery 36 contains one or more battery cells. The battery 36 is designed to be rechargeable. The battery 36 is electrically connected to the drive unit 40 to supply power to the drive unit 40.

[0025] As in Fig. As shown in Figure 2, the drive shaft 40 includes a planetary gear mechanism 46, a first motor 48, and a second motor 50. The drive unit 40 may also include the crankshaft 42, a housing 44, and a controller 52.

[0026] The housing 44 accommodates the planetary gear mechanism 46, the first motor 48, the second motor 50, and the controller 52. The housing 44 rotatably supports the crankshaft 42. The crankshaft 42 extends through the housing 44.

[0027] The planetary gear mechanism 46 includes a sun gear 54, a ring gear 56, planet gears 58, planet pins 60 and a carrier 62. The sun gear 54 is arranged coaxially with the crankshaft 42.

[0028] The ring gear 56 is located outside the sun gear 54 in the radial direction of the crankshaft 42. The ring gear 56 is arranged coaxially with the crankshaft 42. Consequently, the ring gear 56 is also arranged coaxially with the sun gear 54. The output section 64 is connected to the ring gear 56. The output section 64 has one end that is received in the housing 44 and another end that is located outside the housing 44. A bolt B is fastened to the inner circumference of the output section 64 on the part that is located outside the housing 44. The front sprocket 30 is supported by a spline such that the front sprocket 30 is not rotatable in the circumferential direction relative to the output section 64. The bolt B couples the front sprocket 30 to the output section 64 in such a way that the front sprocket 30 is not rotatable in the axial direction.

[0029] The planet gears 58 are located between the sun gear 54 and the ring gear 56. Each planet gear 58 comprises a large-diameter section 58A and a small-diameter section 58B. A gear on the outer circumference of the large-diameter section 58A is positioned opposite the outer circumference of the sun gear 54 and meshes with it. A gear on the outer circumference of the small-diameter section 58B is positioned opposite the inner circumference of the ring gear 56 and meshes with it. Alternatively, instead of the planet gear 58 comprising the large-diameter section 58A and the small-diameter section 58B, a standard planet gear comprising a single gear can be used.

[0030] The planetary pins 60 extend axially through the corresponding planetary gears 58. Each planetary pin 60 rotatably supports the corresponding planetary gear 58. The two ends of each planetary pin 60 are rotatably supported by the carrier 62. As long as the two ends of each planetary pin 60 are rotatably supported by the carrier 62, the planetary pin 60 can be non-rotatably supported by the corresponding planetary gear 58. Conversely, if the planetary pin 60 is rotatably supported by the corresponding planetary gear 58, the two ends of the planetary pin 60 can be non-rotatably supported by the carrier 62.

[0031] The carrier 62 is arranged coaxially with the crankshaft 42. The carrier 62 rotatably holds the planet gears 58 with the planet pins 60. Consequently, the planet gears 58 orbit the sun gear 54 between the sun gear 54 and the ring gear 56.

[0032] The support 62 comprises a first support 62A, which supports one end of each planetary pin 60, and a second support 62B, which supports the other end of each planetary pin 60. The first support 62A is opposite the end of each planetary gear 58 located on the side of the small-diameter section 58B. The second support 62B is opposite the end of each planetary gear 58 located on the side of the large-diameter section 58A. The first support 62A and the second support 62B are coupled together and rotated integrally. The first support 62A can be integrally formed with the second support 62B.

[0033] The crankshaft 42 can be connected to the inner circumference of the first support 62A by, for example, a spline fit or press fit. The support 62 rotates integrally with the crankshaft 42. The rotation of the crankshaft 42 is applied to the support 62.

[0034] The first motor 48 includes a rotating shaft that is radially separated from the crankshaft 42. The first motor 48 includes an output gear 48A that engages with a gear 62C formed by the outer circumference of the second support 62B. The first motor 48 transmits torque to the support 62 through the gear 62C. A one-way clutch may be located between the rotating shaft of the first motor 48 and the support 62. The one-way clutch may be configured to transmit the rotation generated by the first motor 48 to the support 62, and not to transmit the rotation of the support 62 to the first motor 48 if the crankshaft 42 rotates in a particular direction.

[0035] The second motor 50 is arranged coaxially with the crankshaft 42. The second motor 50 is located next to the planetary gear mechanism 46 in the axial direction of the crankshaft 42. The second motor 50 is located further away from the front sprocket 30 than the planetary gear mechanism 46 in the axial direction of the crankshaft 42.

[0036] The second motor 50 is an internal rotor type motor and comprises a stator 50A, which is supported by the housing 44, and a rotor 50B, which is arranged within the stator 50A. The housing 44 includes a support 44A, which is located between the inner circumference of the rotor 50A and the crankshaft 52. The support 44A is tubular and coaxial with the crankshaft 42. The rotor 50B is rotatably supported by the support 44A. The rotor 50B is supported by two bearings 45 on the support 44A. The rotor 50B has an axial end which is coupled to one end of the sun gear 54. This means that the sun gear 54 is integrally formed with the output shaft of the second motor 50. The rotor 50B and the sun gear 54 are rotatable relative to the crankshaft 42. The second motor 50 transmits a torque to the sun gear 54 and controls the rotation of the sun gear 54. The stator 50A is fixed to the housing 44.

[0037] The support 44A includes a gap extending into the space between the inner circumference of the sun gear 54 and the crankshaft 42. A one-way clutch 66 is located between the inner circumference of the sun gear 54 and the outer circumference of the support 44A. The one-way clutch 66 allows the sun gear 54 to rotate in only one direction relative to the support 44A. More specifically, the one-way clutch 66 allows the sun gear 54 to rotate relative to the support 44A in a direction opposite to the direction in which the crankshaft 42 rotates when the bicycle 10 moves forward (hereinafter referred to as the reverse direction of rotation). Furthermore, the one-way clutch 66 restricts the sun gear 54 to rotate relative to the support 44A in the direction in which the crankshaft 42 rotates when the bicycle 10 moves forward (hereinafter referred to as the forward direction of rotation).In other words, the sun gear 54 cannot be rotated in the forward direction relative to the support 44A. When the second motor 50 is not energized, forward rotation is applied to the crankshaft 42, and the one-way clutch 66 restricts the rotation of the sun gear 54. Consequently, the planetary gear mechanism 46 increases the forward rotation speed generated by the crankshaft 42 and transmits the rotation to the output section 64. The one-way clutch 66 can be configured as a roller clutch or a pawl-type clutch.

[0038] The controller 52 includes a drive circuit that drives the first motor 48 and a drive circuit that drives the second motor 50. The controller 52 uses current supplied by the battery 36 (referring to Fig. 1) is provided to drive the first motor 48 and the second motor 50. The controller 52 can be connected to the first motor 48 and the second motor 50 by, for example, conductors.

[0039] The controller 52 controls the first motor 48 and the second motor 50 based on signals from, for example, a torque sensor and a bicycle speed sensor (neither of which are shown). The torque sensor detects a human driving force. The torque sensor is implemented, for example, by a strain gauge, which is arranged on the first support 62A. In this case, the output from the strain gauge is sent to the controller 52 via a wireless communication device or a slip ring. The strain gauge is, for example, a strain gauge. Instead of the torque sensor, the controller 52 can calculate a torque from the current applied to at least the first motor 48 and the second motor 50. In a case where the controller 52 receives an actuation signal to change or switch the assistance force, it can use the torque sensor to calculate the torque.Upon receiving assisting force from an actuating unit (not shown), the controller 52 controls the first motor 48 to increase its output with respect to the human driving force. Furthermore, in a case where the controller 52 receives an actuating signal to change a gear ratio GR of the planetary gear mechanism 46, which is the ratio of the rotational speed output of the planetary gear mechanism 46 to the rotational speed input of the planetary gear mechanism 46, the controller 52 controls the second motor 50 such that the ratio of the rotational speed (or angle of rotation) of the output section 64 to the rotational speed (or angle of rotation) of the crankshaft 42 is in a predetermined gear ratio.

[0040] The controller 52 drives the first motor 48 to transmit a forward rotational torque to the carrier 62. This adds an assisting force to the torque received by the crankshaft 42 and output by the planetary gear mechanism 46.

[0041] The controller 52 drives the second motor 50 to transmit a torque in the reverse direction to the sun gear 54. Referring to Fig. 3. The rotation of the sun gear 54 accelerates the orbital speed of the planet gears 58 relative to the sun gear 54. This increases the rotational speed of the ring gear 56 and thus the gear ratio GR. The gear ratio GR is continuously changed according to the rotational speed of the sun gear 54. Alternatively, the controller 52 can perform a control operation that changes the gear ratio GR, i.e., the rotational speed of the sun gear 54, in a stepwise manner. The controller 52 is connected to an external device via wired or wireless communication. Furthermore, the controller 52 can be configured to change the number of steps or the degree of the gear ratio GR according to the instructions of the external device. The external device could be, for example, a bicycle computer or a PC.

[0042] In one case, where the controller is 52, shown in Fig. 2, when the second motor 50 stops being powered, the second motor 50 is deactivated. As in Fig. As shown in Figure 4, the one-way coupling 66 is located between the sun gear 54 and the support 44A. This restricts the rotation of the sun gear 54 relative to the support 44A. Consequently, if the controller 52 stops supplying power to the second motor 50, the gear ratio GR is maintained according to the number of gears in the planetary gear mechanism 46. In the planetary gear mechanism 46, the carrier 62 serves as an input section, and the ring gear 56 is connected to the output section 64. Consequently, if the sun gear 54 is not rotating relative to the support 44A, the rotational input to the planetary gear mechanism 46 is increased in speed and then output. Therefore, if the controller 52 stops supplying power to the second motor 50, the gear ratio GR is 1 or greater, for example, 1.2 or greater.

[0043] Preferably, the second motor 50 changes the gear ratio GR in at least the range of 1.2 to 1.5. The maximum value of the gear ratio GR, changed by the second motor 50, is, for example, 3.0 or less. In other words, the second motor 50 changes the gear ratio GR in the range of 1 to 3.0.

[0044] The operation and advantages of the bicycle drive unit are described below.

[0045] (1) The drive unit 40 includes the first motor 48, which transmits torque to the carrier 62, and the second motor 50, which controls the rotation of the sun gear 54. Consequently, the change in the gear ratio GR with the second motor 50 and the change in the assist force or support force with the first motor 48 are carried out separately. This allows the control to be implemented according to driving conditions. For example, the bicycle drive unit can be designed to precisely change the gear ratio and the assist force or support force according to the driving conditions or similar factors.

[0046] (2) The gear ratio GR of the planetary gear mechanism 46 is 1 or greater when the rotation of the second motor 50 is stopped. Consequently, compared to a planetary gear mechanism where the gear ratio GR is less than 1 when the second motor is stopped, the range of the gear ratio GR to 1 or greater can be extended without increasing the size of the second motor 50.

[0047] (3) The gear ratio GR of the planetary gear mechanism 46 is 1 or greater. Consequently, when the sun gear 54 is not rotating, the rotational speed of the ring gear 56 is greater than or equal to the rotational speed of the carrier 62. The first motor 48 is connected to the carrier 62. Consequently, compared to a structure that connects a first motor to a ring gear to transmit torque, an increase in the rotational speed of the first motor 48 is limited when the assisting or supporting force is applied. This reduces the power consumption of the first motor 48.

[0048] (4) The second motor 50 is arranged coaxially with the crankshaft 42. Consequently, compared to a structure that arranges the second motor 50 outwards in the radial direction of the crankshaft 42, an enlargement of the drive unit 40 in the radial direction of the crankshaft 42 is limited.

[0049] (5) The sun gear 54 is integrally formed with the output shaft of the second motor 50. This reduces the number of components in the drive unit 40.

[0050] (6) The rotating shaft of the first motor 48 is separated from the crankshaft 42 in the radial direction of the crankshaft 42. Consequently, compared to a case in which the rotating shaft of the first mode 48 is arranged coaxially with the crankshaft 42 of the drive unit 40, an enlargement in the axial direction of the crankshaft 42 is limited.

[0051] (7) In a case where the one-way coupling 66 is not located between the sun gear 54 and the support 44A and the power supply to the second motor 50 is stopped, the rotation of the sun gear 54 relative to the support 44A is not restricted. Consequently, a reverse rotational force is applied to the planet gears 58 and the sun gear 54 is rotated in the forward direction. As a result, the carrier 62 and the ring gear 56 will cease to rotate relative to the housing 44 and the planetary gear mechanism 46 will not output any rotation.

[0052] The drive unit 40 includes the one-way coupling 66, which is located between the sun gear 54 and the housing 44. This allows the planetary gear mechanism 46 to output a rotation even when the power supply to the second motor 50 is stopped. Furthermore, to minimize the gear ratio GR, the power supply to the second motor 50 can be stopped. This allows the power consumption to be reduced compared to a structure that supplies power to the second motor 50 to maintain the phase of the sun gear 54 relative to the support 44a.

[0053] (8) The output section 64 is located outside the planetary gear mechanism 46 in the axial direction of the crankshaft 42. Consequently, compared with a structure in which the section to which the front sprocket 30 is coupled is located inside the planetary gear mechanism 46 in the axial direction of the crankshaft 42, coupling and removal of the front sprocket 30 are facilitated.

[0054] (9) Fig. Figure 5 shows a drive unit 200 not according to the invention, which inputs a rotation of the crankshaft 42 onto the ring gear 206 and outputs the rotation of a carrier 208. In the drive unit 200, the second motor 50 is supported by a housing 212. Consequently, in a case where an output section 210 is located on the outside in the axial direction of the planetary gear mechanism 202 and the carrier 208 is located between the ring gear 206 and the second motor 50 in the axial direction of the planetary gear mechanism 202, the carrier 208 extends between the second motor 50 and the crankshaft 42. Consequently, the carrier 208 and the planetary gear mechanism 202 have complex structures.

[0055] In the drive unit 40, the output section 64 is coupled to the ring gear 56. Consequently, the carrier 62 has a simple structure. This simplifies the structure of the planetary gear mechanism 72 and limits the size of the drive unit 40.

[0056] The present invention is not limited to the above embodiment. For example, the present invention can be modified as described below. As in Fig. As shown in Figure 6, the second motor 50 can be arranged on the radial outer side of the crankshaft 42. In this case, a stepped gear arranged coaxially with the crankshaft 42 can be used as the sun gear 54. The one-way clutch 66 can be located between the sun gear 54 and the housing 44.

[0057] As in Fig. As shown in Figure 6, the first motor 48 can be arranged coaxially with the crankshaft 42. In this case, the carrier 62 can include an inner gear that engages with an output gear of the first motor 48.

[0058] The controller 52 can drive the second motor 50 in the forward direction of rotation. In this case, the one-way clutch 66 is omitted. If the second motor 50 rotates the sun gear 54 in the forward direction, the gear ratio GR is reduced. If the rotational speed of the second motor 50 is increased, the gear ratio GR is reduced to 1 or less; in this case, it is preferred that the second motor 50 varies the gear ratio GR in the range of 0.2 to 3.0.

[0059] A speed reduction mechanism can be located between the crankshaft 42 and the carrier 62 or between the ring gear 56 and the front sprocket 30. In this case, the speed reduction mechanism can reduce the gear ratio GR to less than 1. The speed reduction mechanism can be implemented by at least two or more gears or by a planetary gear mechanism.

[0060] The one-way coupling 66 can be located between the rotor 50B and the support 44a. Alternatively, the one-way coupling 66 can be located between the rotor 50B and a section of the housing 44 that is different from the support 44a.

[0061] The second motor 50 can be an external rotor type motor in which the rotor 50B is arranged relative to the starter 50A. The sun gear 54 can be separated from the output shaft of the second motor 50, or the sun gear 54 can be connected to the output shaft of the second motor 50 by a spline fit. In this case, the one-way coupling 66 can be located between the output shaft of the second motor 50 and the support 44A.

[0062] The one-way coupling 66 can be omitted. In this case, to limit the rotation of the sun gear 54 relative to the housing 44, the second motor 50 is controlled to prevent rotation and thus to keep the sun gear 54 in the rotational phase relative to the housing 44.

[0063] As in Fig. As shown in Figure 7, instead of the one-way clutch 66, a one-way clutch 68 can be located between the carrier 62 and the ring gear 56. The one-way clutch 68 allows the output section 64 and the ring gear 56 to rotate in the forward direction relative to the crankshaft 42 and the carrier 62. More specifically, in a case where the output section 64 and the ring gear 56 rotate faster than the crankshaft 42 and the carrier 62, rotation of the output section 64 and the ring gear 56 relative to the crankshaft 42 and the carrier 62 is permitted.The one-way clutch 68 restricts the rotation of the output section 64 and the ring gear 56 in the reverse direction relative to the crankshaft 42 and the carrier 62. More specifically, when the rotational speed of the output section 64 and the ring gear 56 in the forward direction becomes equal to the rotational speed of the crankshaft 42 and the carrier 62, the output section 64 and the ring gear 56 are coupled to the crankshaft 42 and the carrier 62 and rotate integrally. Consequently, for example, in a case where the power supply to the second motor 50 is stopped and the gear ratio becomes GR 1, the one-way clutch 68 serves to rotate the carrier 62 and the ring gear 56 integrally in the forward direction. Consequently, even in a case where the power supply to the second motor 50 is stopped, the rotation of the crankshaft 42 can be transmitted to the front sprocket 30.The one-way coupling 68 can be designed as a roller coupling or a latch type coupling.

[0064] As in Fig. 8 shown, in the modified example of Fig. 7, the one-way coupling 68 can be located between the crankshaft 42 and the output section 64. This also provides the advantages of the modified example shown in Fig. 7, achieved.

[0065] The crankshaft 42 can be omitted from the drive unit 40, and a crankshaft separate from the drive unit 40 can be coupled to the drive unit 40. At least one of the first engine 48 and the second engine 50 can be arranged outside the housing 44.

[0066] In a planetary gear mechanism 72 of a drive unit 70 not according to the invention, shown in Fig. 9, the rotation of the crankshaft 42 is input to a carrier 78, and the rotation of a sun gear 74 is output to the front sprocket 30. A ring gear 76 is rotatable relative to the housing 44. The first motor 48 is connected to a carrier 78, and the torque of the first motor 48 is transmitted to the carrier 78. The second motor 50 is connected to the ring gear 56 to transmit torque to the ring gear 76 and control its rotation. In a case where the rotation of the ring gear 76 relative to the housing 44 is limited, the gear ratio GR of the planetary gear mechanism 72 is less than 1. Consequently, the gear ratio GR can be continuously varied within a range of less than 1 and a range of 1 or greater by driving the second motor 50 in the reverse direction.The gear ratio GR can be further reduced by driving the second motor 50 in the forward direction of rotation.

[0067] As in Fig. 10 shown, with drive unit 70 shown in Fig. 9, the first motor 48 can be connected to the sun gear 74. In this case, the torque of the first motor 48 is transmitted to the sun gear 74.

[0068] In a planetary gear mechanism 82 of a drive unit 80 not according to the invention, shown in Fig. 11, the rotation of the crankshaft 42 is input to a sun gear 84, and the rotation of the carrier 88 is output to the front sprocket 30. The ring gear 86 is rotatable relative to the housing 44. The first motor 48 is connected to the sun gear 84, and the torque of the first motor 48 is transmitted to the sun gear 84. The second motor 50 is connected to the ring gear 86 to transmit torque to the ring gear 86 and to control its rotation. In a case where the rotation of the ring gear 86 relative to the housing 44 is limited, the gear ratio GR of the planetary gear mechanism 82 is less than 1. Consequently, the gear ratio GR can be continuously varied within a range of less than 1 and a range of 1 or greater by driving the second motor in the forward direction of rotation.The gear ratio can be further reduced by driving the second motor 50 in the reverse direction.

[0069] As in Fig. 12 shown, with drive unit 80 shown in Fig. 11. The first motor 48 can be connected to the support 88. In this case, the torque of the first motor 48 is transmitted to the support 88.

[0070] In a planetary gear mechanism 92 of a drive unit 90 not according to the invention, shown in Fig. 13, the rotation of the crankshaft 42 is input to a ring gear 96, and the rotation of a sun gear 94 is output to the front sprocket 30. A carrier 98 is rotatable relative to the housing 44. The first motor 48 is connected to the ring gear 96, and the torque of the first motor 48 is transmitted to the ring gear 96. The second motor 50 is connected to the rotary gear 98 to transmit torque to the rotary gear 98 and to control the rotation of the carrier 98. In the planetary gear mechanism 92, in a case where the rotation of the carrier 98 relative to the housing 44 is limited, the direction of rotation of the ring gear 96 differs from the direction of rotation of the sun gear 94. Consequently, a transmission gear 100 is located between the sun gear 94 and the front sprocket 30 to change the direction of rotation. The transmission wheel 100, the sun wheel 94 and the front sprocket 30 form a planetary gear mechanism.In this case, the transmission gear 100 acts as a planet gear, the sun gear 94 acts as a sun gear, and the front sprocket 30 acts as a ring gear. A support for the transmission gear 100 can be fixed to a housing to reverse the direction of rotation of the sun gear 94 and the front sprocket 30. The transmission gear 100 can be located between the crankshaft 42 and the ring gear 96.

[0071] As in Fig. 14 shown, with drive unit 90 shown in Fig. 13, the first motor 48 can be connected to the sun gear 94. In this case, the torque of the first motor 48 is transferred to the sun gear 94.

[0072] In a planetary gear mechanism 104 of a drive unit 102 not according to the invention, shown in Fig. In the planetary gear mechanism 104, the rotation of the crankshaft 42 is input to a sun gear 106, and the rotation of a ring gear 108 is output to the front sprocket 30. A carrier 110 is rotatable relative to the housing 44. The first motor 48 is connected to the sun gear 106, and the torque of the first motor 48 is transmitted to the sun gear 106. The second motor 50 is connected to the carrier 110 to transmit torque to the carrier 110 and to control its rotation. In the planetary gear mechanism 104, if the rotation of the carrier 110 relative to the housing 44 is limited, the direction of rotation of the sun gear 106 differs from the direction of rotation of the ring gear 108. Consequently, a transmission gear 112 is located between the ring gear 108 and the front sprocket 30 to change the direction of rotation. The transmission wheel 112, the ring gear 108 and the front sprocket 30 form a planetary gear mechanism.In this case, the transmission gear 112 serves as its planet gear, the ring gear 108 serves as a sun gear, and the front sprocket 30 serves as a ring gear. A support bracket for the transmission gear 112 is fixed to a housing to reverse the direction of rotation of the sun gear 94 and the front sprocket 30. The transmission gear 112 can be located between the crankshaft 42 and the sun gear 106.

[0073] As in Fig. 16 shown, with the drive unit 112 shown in Fig. 15. The first motor 48 can be connected to the ring gear 108. In this case, the torque of the first motor 48 is transmitted to the ring gear 108. DESCRIPTION OF REFERENCE MARKS 10 bicycles 40 drive unit 42 Crankshaft 44 cases 44A support 46 Planetary gear mechanism 54 Sun wheel 56 Ring gear 58 planetary gear 62 carriers 64 Output section 66 One-way coupling 48 first engine 50 second engine 52 Controller 68 One-way coupling

Claims

[1] Bicycle drive unit (40) comprising: a planetary gear mechanism (46) comprising a sun gear (54), a ring gear (56) which is / will be arranged coaxially with the sun gear (54), planet gears (58) which are located between the sun gear (54) and the ring gear (56), and a carrier (62) which rotatably holds the planet gears (58) and receives a rotation of a crankshaft (42), wherein the crankshaft (42) and the carrier (62) are / will be connected, a first motor (48) configured to transmit a torque to the support (62), wherein the first motor (48) is connected to the support (62); a second motor (50) configured to transmit torque to the sun gear (54) and to control rotation of the sun gear (54); a housing (44) that accommodates at least the planetary gear mechanism (46); and a one-way coupling (66; 68) located between the sun gear (54) and the housing (44), wherein the one-way coupling (66; 68) allows the sun gear (54) to rotate relative to the housing (44) in only one direction. [2] Bicycle drive unit (40) according to claim 1, further comprising an output section (64) which can be coupled to a front chain wheel (30), wherein the hollow wheel (56) is / is connected to the output section (64). [3] Bicycle drive unit (40) according to claim 1 or 2, further comprising a crankshaft (42). [4] Bicycle drive unit (40) according to one of claims 1 to 3, in which the support (62) is / is arranged coaxially with the crankshaft (42) with respect to the crankshaft (42). [5] Bicycle drive unit (40) according to claim 4, in which the sun gear (54) is / is arranged coaxially with the crankshaft (42) with respect to the crankshaft (42). [6] Bicycle drive unit (40) according to one of claims 1 to 5, in which the second motor (50) is / will be arranged coaxially with the crankshaft (42) with respect to the crankshaft (42). [7] Bicycle drive unit (40) according to claim 6, when dependent on claim 5, in which the sun gear (54) is / is formed integrally with an output shaft of the second motor (50). [8] Bicycle drive unit (40) according to one of claims 1 to 7, in which a rotating shaft of the first motor (48) is separated from the crankshaft (42) in a radial direction of the crankshaft (42). [9] Bicycle drive unit (40) according to any one of claims 1 to 8, further comprising: a housing (44) that accommodates at least the planetary gear mechanism (46); and a one-way coupling (66; 68) located between an output shaft or rotor of the second motor (50) and the housing (44), wherein the one-way coupling (66; 68) allows the output shaft or rotor of the second motor (50) to rotate relative to the housing (44) in only one direction. [10] Bicycle drive unit (40) according to claim 5, wherein the housing (44) includes a support (44A) located in a space extending between an inner circumference of the sun gear (54) and the crankshaft (42); and the one-way coupling (66; 68) is located between the sun gear (54) and the support (44A). [11] Bicycle drive unit (40) according to claim 2 or according to any one of claims 3 to 10, if dependent on claim 2, further comprising: a one-way coupling (66; 68) located between the crankshaft (42) or carrier (62) and the ring gear (56) or output section (64), wherein the one-way coupling (66; 68) allows the output section (64) to rotate relative to the crankshaft (42) in only one direction. [12] Bicycle drive unit (40) according to one of claims 1 to 11 in which at least one of the first motor (48) and the second motor (50) is / is received in the housing (44). [13] Bicycle drive unit (40) according to one of claims 1 to 12, in which the second motor (50) includes a gear ratio of the planetary gear mechanism (46) that changes at least a range of 1.2 to 1.

5. [14] Bicycle drive unit (40) according to one of claims 1 to 13, in which the second motor (50) changes a gear ratio of the planetary gear mechanism (46) in a range of 0.2 to 3.

0. [15] Bicycle drive unit (40) according to one of claims 1 to 14, further comprising a controller (52) that controls the first motor (48) and the second motor (50).

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