bicycle drive unit

Abstract

Bicycle drive unit (10), comprising: an input rotary shaft (12); an output part (14); a transmission mechanism (18; 80) which comprises at least two switching stages and which can change the speed of a rotary input which is / is input by the input rotary shaft (12) and can output the rotary input to the output part (14); an assistance motor (66) which is / will be coupled to a power transmission path from the input rotating shaft (12) to the output part (14), and which is driven by a muscular force; and a shifting mechanism (20; 82) which can switch a gear shift state of the transmission mechanism (18; 80) using a rotational force of the assist motor (66), wherein the transmission mechanism (18; 80) comprises a planetary gear mechanism (30), and wherein the planetary gear mechanism (30) comprises an input body which is rotatably supported by a support member, and on which the rotary input of the input rotary shaft (12) is / is input; a starting body which is / is rotatably supported by the supporting member, and outputs the rotation input externally; and a transmission body (86), wherein the switching mechanism (20; 82) further comprises a one-way coupling (48; 96) which is provided between the input body and the output body and which controls a rotation of the transmission body (86).

Description

[0001] This application claims priority over Japanese patent application 2015-063155, filed on March 25, 2015. The complete disclosure of Japanese patent application 2015-063155 is hereby incorporated herein by reference.

[0002] The present invention relates to a bicycle drive unit.

[0003] A bicycle drive unit is described in Japanese patent application JP 5 523 636 B1, which includes a transmission mechanism capable of reducing the speed of a rotational input to a crankshaft and outputting this rotation to an output part, as well as a switching mechanism for switching between a state in which the crankshaft and the output part are connected and a state in which the connection between the crankshaft and the output part is disconnected. When the switching mechanism is in a state in which the crankshaft and the output part are disconnected, the rotation input to the crankshaft is slowed down by the transmission mechanism and output to the output part.When the shifting mechanism is in a state where the crankshaft and the output shaft are connected, the rotation input to the crankshaft is transmitted to the output shaft without being slowed down or decelerated by the transmission mechanism. This means that the bicycle drive unit is capable of achieving two gear ratios with the shifting mechanism.

[0004] In the transmission mechanism of the bicycle drive unit as described above, the more the amount of torque applied to the shifting mechanism is reduced, the more difficulty the shifting mechanism has in disengaging or releasing the connection between the crankshaft and the output part. For this reason, the transmission power decreases.

[0005] Gear units or drive units are known from the prior art, such as those from DE 10 2008 064 514 A1, EP 2 444 312 A1, US 8 100 208 B2 or DE 60 2004 009 488 T2.

[0006] It is an object of the present invention to provide a bicycle drive unit that is capable of improving the shifting performance.

[0007] The bicycle drive unit according to the present invention comprises a transmission mechanism having at least two switching stages, capable of changing the speed of a rotary input supplied by an input rotating shaft, and capable of outputting the rotary input to the output part; an assist motor connected to a power transmission path from the input rotating shaft to the output part, driven by a muscle force; and a shifting mechanism for switching a gear position from the transmission mechanism using a rotational force from the assist motor. The transmission mechanism comprises a planetary gear mechanism.The planetary gear mechanism comprises an input body, rotatably supported by a support member, at which the rotary input of the input rotating shaft is applied, an output body, rotatably supported by the support member, which outputs the rotary input to the outside, and a transmission body, wherein the switching mechanism further comprises a one-way coupling, which is provided between the input body and the output body, and which controls a rotation of the transmission body.

[0008] Preferably, at least one part of the switching mechanism is coupled to the transmission path between the assist motor and the output part.

[0009] Preferably, the one-way coupling integrally rotates the input body and the output body if the rotational speed of the input body in one direction is equal to or greater than the rotational speed of the output body in one direction; or if the rotational speed of the input body in one direction is less than the rotational speed of the output body in one direction, whereby a relative rotation between the input body and the output body is allowed.

[0010] Preferably, the support member can be rotated integrally with the transmission body, and the switching mechanism comprises a connecting part which is provided on the transmission body or on a counter section which is opposite the transmission body, and which is movably arranged between a projecting position in which the rotation of the transmission body is controlled in at least one direction, and a retracted position in which the rotation of the transmission body is not controlled; and a control unit which moves the connecting part from the projecting position to the retracted position using the torque of the assist motor.

[0011] Preferably, the control unit pushes the connecting part and moves it from the protruding position to the retracted position.

[0012] Preferably, a large number of connecting parts are provided around a rotational axis of the support member.

[0013] Preferably, the control unit comprises an annular member which can be rotated integrally with the starting body and which includes a groove which becomes flatter in a radial direction towards a circumferential direction in a section opposite the connecting part.

[0014] Preferably, the assist motor is connected to the output body or to an upstream side of the output body on the power transmission path.

[0015] Preferably, the transmission body comprises a sun gear which rotates integrally with the support member, wherein the output body comprises a ring gear which is / will be arranged coaxially around the sun gear; and the input body comprises a carrier which is arranged between the sun gear and the ring gear, and which rotates integrally with a plurality of planet gears.

[0016] Preferably, the connecting part is provided on the support member.

[0017] Preferably, the transmission mechanism comprises a plurality of rotating bodies, including a controlling rotating body; wherein the switching mechanism comprises a connecting part which is provided on the controlling rotating body, or on a counter section which is opposite the controlling rotating body, and which can be moved between a projecting position in which the rotation of the controlling rotating body is controlled in at least one direction, and a retracted position in which the rotation of the controlling rotating body is not controlled; and a control unit which moves the connecting part from the projecting position to the retracted position using the rotational force of the assist motor.

[0018] Preferably, the control unit pushes the connecting part and moves the connecting part from the protruding to the retracted position.

[0019] Preferably, a large number of connecting parts are provided around a rotational axis of the rotating body to be controlled.

[0020] Preferably, the control unit comprises an annular link which can be rotated with another rotating body, besides the rotating body to be controlled, among the plurality of rotating bodies including the transmission mechanism; wherein the annular link of the control unit comprises a groove which becomes shallower in a radial direction towards a circumferential direction in a section opposite the connecting part.

[0021] Preferably, the assist motor is connected to another rotating body or to the upstream side of another rotating body on the power transmission path.

[0022] Preferably, the ring-shaped link pushes the connecting part radially inwards or inwards.

[0023] Preferably, the connecting part comprises a latch element, claw element, or locking element.

[0024] Preferably, the control unit further comprises a cam for moving the ring-shaped element in a direction of rotation, and an electric motor for driving the cam.

[0025] Preferably, the input rotating shaft is a crankshaft to which a muscle driving force is / is applied.

[0026] Preferably, the auxiliary motor is arranged radially outwards from the crankshaft.

[0027] Preferably, the transmission mechanism comprises a first rotating body which is rotated integrally with the input rotating shaft; a second rotating body which is rotated about an axis whose position with respect to the input rotating shaft does not change, and to which a rotation of the first rotating body is / is transmitted; a third rotating body which is rotated integrally with the second rotating body; and a fourth rotating body to which the rotational force of the third rotating body is / is transmitted, and which is rotated integrally with the output part;wherein the switching mechanism comprises a connecting part which is provided on a counter section which is opposite one of the second rotating body and the third rotating body, and which is moved between a projecting position in which a rotation of one of the second rotating body and the third rotating body is / is controlled in at least one direction, and a retracted position in which the rotation of one of the second rotating body and the third rotating body is / is not controlled; and a control unit which moves the connecting part from the projecting position to the retracted position using the rotational force of the assist motor.

[0028] The bicycle drive unit described above can improve transmission performance. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a cross-sectional view of a bicycle drive unit according to a first embodiment. Fig. Figure 2 is a partial perspective view of a switching mechanism of the bicycle drive unit illustrated in Fig. 1. Fig. Figure 3 is a perspective view of a hollow gear and an annular link of the bicycle drive unit illustrated in Fig. 1. Fig. Figure 4 is a perspective view of the ring-shaped link of the switching mechanism illustrated in Fig. 2. Fig. Figure 5 is a partial elevation view of the ring gear and a part of the annular link illustrated in Fig. 3. Fig. Figure 6 is an enlarged, partial cross-sectional view of a connecting part of the switching mechanism of Fig. 1, in a protruding position. Fig. Figure 7 is a cross-sectional view of the connecting part of the switching mechanism along section line 7-7 of Fig. 6. Fig. Figure 8 is an enlarged partial cross-sectional view of the connecting part of the switching mechanism illustrated in Fig. 1, in a retracted position. Fig. Figure 9 is a cross-sectional view of the connecting part of the switching mechanism along section line 9-9. Fig. 8. Fig. Figure 10 is a partial cross-sectional view of the connecting part of the switching mechanism, illustrating the actuation of the connecting part of the switching mechanism. Fig. 1. Fig. Figure 11 is a partial cross-sectional view of the connecting part of the switching mechanism, illustrating the actuation of the connecting part of the switching mechanism. Fig. 1. Fig. Figure 12 is a partial perspective view of a torque sensor of the bicycle drive unit illustrated in Fig. 1. Fig. Figure 13 is a partial perspective view of the torque sensor, in a state where a screen plate is attached to the torque sensor of the bicycle drive unit, illustrated in Fig. 1 is attached. Fig. Figure 14 is a schematic cross-sectional view of a bicycle drive unit according to a second embodiment. Fig. Figure 15 is a schematic cross-sectional view of a connecting part of a switching mechanism of the bicycle drive unit, illustrated in Fig. 14, in a retracted position.

[0029] A bicycle drive unit according to a first embodiment is now described with reference to the Fig. 1 - 11 described.

[0030] As in Fig. As shown in Figure 1, the drive unit 10 comprises an input rotating shaft 12, an output part 14, a housing 16, a transmission mechanism 18, a switching mechanism 20, an assistance mechanism 22, and a control unit 24. In the first embodiment, the input rotating shaft 12 is a bicycle crank shaft that receives pedal force from a rider. The output part 14 is configured to output the rotational input from the input rotating shaft 12 to a sprocket S. The housing 16 rotatably supports the rotating shaft 12 and the output part 14. The transmission mechanism 18 is configured to output the rotational input that was applied from the input rotating shaft 12 to the output part 14 due to an actuation state of the switching mechanism 20. Preferably, the drive unit 10 further comprises a torque sensor 78, which is explained below.

[0031] The housing 16 is attached to the bicycle frame (not shown). The housing 16 accommodates part of the input drive shaft 12, part of the output part 14, the transmission mechanism 18, the shifting mechanism 20, part of the assist mechanism 22, and the control unit 24.

[0032] The input shaft 12 is rotatably supported by the housing 16. Both ends of the input shaft 12 are exposed outside the housing 16. A crank arm (not shown) can be attached to each end of the input shaft 12. In this way, muscle power is applied to the input shaft 12 via the crank arms. The input shaft 12 can be a hollow shaft. The housing 16 rotatably supports a first external axial end of the input shaft 12 via a bearing 17A. The output section 14 rotatably supports a second external axial end of the input shaft 12 via a second bearing 17B.

[0033] The output part 14 has a tubular shape, i.e., a tubular shaft. The output part 14 is arranged coaxially around the input rotating shaft 12. A first end of the output part 14 is exposed outside the housing 16. A second end of the output part 14 has a plurality of teeth 14B. An outer peripheral part of a central section of the output part 14 is supported by the housing 16 via a bearing 17C. The output part 14 includes a mounting section 14A, which is configured to be attached to an inner peripheral part of the sprocket S. The mounting section 14A is arranged coaxially to an axial end of the input rotating shaft 12. The mounting section 14A has a plurality of splines on its outer peripheral surface. The sprocket S has a multitude of splines formed on an inner periphery adapted to the splines of the mounting section 14A.The sprocket S is held on the output part 14 by a bolt B, which is screwed into an inner peripheral part of the output part 14. In this way, the sprocket S is clamped between the output part 14 and the bolt B. The output part 14 can be designed to be split in an axial direction with respect to the axis of rotation of the input rotary shaft 12.

[0034] The transmission mechanism 18 comprises a transmission shaft 26, a transmission mechanism 28, and a planetary gear mechanism 30. The transmission shaft 26 includes a support element and a rotating body to be controlled. The transmission mechanism 18 comprises two switching stages or switching states and can change the input rotational speed, which is input by the input rotating shaft 12 and which is output to the output part 14.

[0035] The transmission shaft 26 is arranged radially outwards from the input shaft 12 with respect to the radial direction of the input shaft 12's axis of rotation. The transmission shaft 26 is arranged parallel to the input shaft 12. The transmission shaft 26 is rotatably supported by the housing 16. Both axial ends of the transmission shaft 26 are supported by the housing 16 via a pair of bearings 17D and 17E, each arranged at two axially spaced positions. The transmission shaft 26 is rotatable about a stationary central axis C, the position of which remains constant relative to the input shaft 12. A first axial end of the transmission shaft 26 is supported by bearing 17D, which is a ball bearing, while a second axial end of the transmission shaft 26 is supported by bearing 17E, which is a needle bearing.

[0036] The transmission mechanism 28 comprises a first transmission gear 32 and a second transmission gear 34. The first transmission gear 32 is arranged coaxially around the input rotating shaft 12. The second transmission gear 34 is arranged coaxially around the transmission shaft 26.

[0037] The first transmission gear 32 comprises a multitude of external gear teeth. The inner periphery of the first transmission gear 32 is not rotatably supported by the input shaft 12. In other words, the first transmission gear 32 is not rotatably coupled to the input shaft 12. For example, the first transmission gear 32 is relatively non-rotatably coupled to the input shaft 12 via a spline fit or an interference fit.

[0038] The second transmission gear 34 comprises a multitude of external gear teeth. The second transmission gear 34 is rotatably supported by the transmission shaft 26 via a bearing or similar device. The external gear teeth of the first transmission gear 32 mesh with the external gear teeth of the second transmission gear 34. Therefore, rotation of the input shaft 12 is transmitted to the second transmission gear 34 via the first transmission gear 32.

[0039] The planetary gear mechanism 30 comprises a sun gear 36, a plurality of planet gears 38, a carrier 40, and a ring gear 42. The sun gear 36 represents a transmission element. The carrier 40 represents an input element. The ring gear 42 represents an output element. The carrier 40 also represents a first rotating element, while the ring gear 42 also represents a second rotating element.

[0040] The sun gear 36 is arranged coaxially around the transmission shaft 26. The sun gear 36 is integrated with the transmission shaft 26. For this reason, the transmission shaft 26 can be rotated integrally with the sun gear 36.

[0041] The planet gears 38 are arranged around the sun gear 36. The planet gears 38 are operatively arranged between the sun gear 36 and the ring gear 42. The teeth of the planet gears 38 mesh with the outer teeth of the sun gear 36 and with the inner teeth or the internal teeth of the ring gear 42.

[0042] The carrier 40 rotatably supports the planet gears 38 and rotates the planet gears 38 integrally about the sun gear 36. A first axial end of the carrier 40 of the transmission shaft 26 is connected to the first transmission gear 32 via a spline fit, a press fit, or similar. In this way, the carrier 40 can rotate integrally with the first transmission gear 32. In other words, the carrier 40 is rotatably supported by the transmission shaft 26 via the first transmission gear 32. The rotation of the input shaft 12 is applied to the carrier 40 via the first transmission gear 32.

[0043] The ring gear 42 is arranged coaxially around the sun gear 36. The ring gear 42 comprises a first end 42A on one side, which is connected to the planet gear 38 with respect to the axial direction of the transmission shaft 26, and a second end 42B on the opposite side of the first end 42A. The first end 42A of the ring gear 42 covers the planet gears 38. The inner periphery of the second end 42B of the ring gear 42 is rotatably supported by the transmission shaft 26 via a bearing or similar device.

[0044] The outer periphery of the first end 42A of the ring gear 42A has a plurality of first gear teeth 42C. The outer periphery of the second end 42B of the ring gear 42 has a plurality of second gear teeth 42D. The second gear teeth 42D mesh with the gear teeth 14B, which are formed on the outer periphery of the output part 14. This means that the ring gear 42 outputs the rotational input outwards. The number of teeth of the second gear teeth 42D is less than the number of teeth of the first gear teeth 42C. An annular section 42F is formed between the first gear teeth 42C and the second gear teeth 42D of the ring gear 42. The annular section 42F is rotatably supported by the housing 16 via a bearing 17F.

[0045] The shifting mechanism 20 is designed to switch the gear shift state of the transmission mechanism 18. The shifting mechanism 20 comprises a retaining element 44, a first preloading element 46 (see Fig. 2), a one-way coupling 48, a connecting part 50 and a control unit 52.

[0046] The retaining element 44 has a cylindrical shape. The retaining element 44 is arranged coaxially around the transmission shaft 26. The retaining element 44 is fixed to the transmission shaft 26 such that it rotates integrally with the transmission shaft 26. The retaining element 44 comprises a plurality of spline grooves 44C in an inner periphery. The spline grooves 44C engage with the splines defined by a plurality of spline grooves 26C provided on an outer periphery of the transmission shaft 26. This spline engagement of the spline grooves 44C with the splines defined by the spline grooves 26C prevents relative rotation of the transmission shaft 26 with respect to the retaining element 44 about the central axis C. As shown in Fig. As shown in Figure 6, the axial movement of the retaining element 44 is restricted or limited by a fixing element 45 and a stepped section 26B, which is formed on the transmission shaft 26 by varying the diameter of the transmission shaft 26. The fixing element 45 is, for example, designed as an E-ring. The retaining element 44 is arranged in a position adjacent to the second end 42B of the ring gear 42 in the axial direction of the transmission shaft 26.

[0047] A wide variety of connecting parts 50, as in Fig. 2 shown, is about the axis of rotation of the transmission shaft 26 (see Fig. 1) provided. Each of the connecting parts 50 comprises a pawl element 54. Each pawl element 54 is attached to the retaining element 44 such that at least a section of it can be received in a groove 44A, which is formed on the outer peripheral part of the retaining element 44. The end of each pawl element 54 on the opposite side of the ring gear 42 in the axial direction of the transmission shaft 26 is against the opposite section 16A of the housing 16, as shown in Fig. Figure 6 shows the opposite section 16A. The opposing section 16A comprises an inner peripheral part 16B, which is formed in an annular shape around the axis of the transmission shaft 26. The inner peripheral part 16B has a plurality of grooves 16C formed within it. The grooves 16C are spaced at predetermined distances or intervals in the circumferential direction of the inner peripheral part 16B. Each of the grooves 16C has the same shape as a so-called pawl groove or ratchet groove. Each of the pawl elements 54 is received in one of the grooves 44A of the retaining element 44 and projects at least partially from its respective groove 44A. In this way, the retaining elements 54 can be moved between a connected position, which connects the grooves 16C, and a retracted position, which separates the grooves 16C from the opposing section 16A. The connecting position in the following embodiment corresponds to the protruding position.The opposing section 16A can be integrally formed with the housing 16 or can be formed as a separate body from the main body of the housing 16. The opposing section 16A is preferably made of metal. In the case that the opposing section 16A is formed as a separate body from the main body of the housing 16, a mounting section for mounting the opposing section 16A is formed in the inner peripheral part of the main body of the housing 16 and prevents the opposing section 16A from rotating about the central axis C (see Figure 1). Fig. 1) to rotate. The main body of the housing 16 can be made of plastic or metal.

[0048] The first preload element 46 is an annular spring. The first preload element 46 is inserted into a groove 54A, which is formed on the outer surfaces of each of the latch elements 54, and into a circumferential groove 44B (see Fig. 2), which is formed on the outer periphery of the retaining member 44, fitted. The first preloading member 46 applies a force to each of the latching members 54 in order to preload each of the latching members 54 towards the connecting position.

[0049] The control unit 52 comprises a first annular element 56, a second preload element 58, a cam 60, a coupling element 62, and an actuator 64. The cam 60 is configured to move the annular element 56 in the axial direction of the transmission shaft 26. The actuator 64 is configured to drive the cam 60. The actuator 64 is, for example, an electric motor.

[0050] As in Fig. As shown in Figure 3, the annular link 56 is arranged coaxially around the ring gear 42. The annular link 56 covers the second end 42B of the ring gear 42. The annular link 56 is arranged in a position closer to the connecting part 50 (see Figure 3). Fig. 1) is the second gear 42D with respect to the axial direction of the transmission shaft 26 (see Fig. 1).

[0051] As in Fig. As shown in Figure 4, the annular link 56 has a plurality of recesses 56A, a plurality of grooves 56B, and an annular projection 56A. The recesses 56A are formed in an inner peripheral part of the annular link 56. The grooves 56B are formed on the side surface section (end surface section in the axial direction). The annular projection 56E is formed in the outer peripheral part of the annular link 56. The annular projection 56E is located in a section of the outer peripheral part of the annular link 56 that is situated on one side near the second gear 42D (see Figure 4). Fig. 3) of the ring gear 42 is located, formed.

[0052] The recesses 56A extend axially in a section of the inner periphery of the annular link 56 on the side with the ring gear 42. The outer periphery of the ring gear 42 has a plurality of projections 42E (see Fig. 3) The projections 42E extend in the axial direction of the transmission shaft 26. The projections 42E fit into the recesses 56A. The recesses 56A are slightly larger than the projections 42E. Since the recesses 56A fit into the projections 42E, the annular link 56 rotates integrally with the ring gear 42 when the ring gear 42 rotates. In addition, the recesses 56A of the annular link 56 can extend axially along the projections 42E (see Fig. 1) move. For this reason, the ring-shaped link 56 can be moved in the axial direction with respect to the ring gear 42.

[0053] The grooves 56B are located on the side surface section of the inner periphery of the annular member 56 on the side facing the connecting part 50, as shown in Fig. 6 is shown, facing the, formed. The grooves 56B are opposite the latch elements 54. As in Fig. As shown in Figure 5, each of the grooves 56B comprises a first guide surface 56C, which becomes shallower in the axial direction towards one circumferential direction of the annular member 56. Furthermore, each of the grooves 56B comprises a second guide surface 56D, which becomes smaller in the radial direction at the other end in the circumferential direction of the annular member 56. The grooves 56B are continuous in the circumferential direction of the annular member 56. An inner peripheral surface 56F of the annular member 56 on the side facing the connecting part 50 is continuous with the grooves 56B. The inner peripheral surface 56F is formed in an annular shape.

[0054] As in Fig. As shown in Figure 6, the second preload member 58 is attached between the ring gear 42 and the end of the annular link 56 on the side facing the ring gear, with respect to the axial direction of the transmission shaft 26. The second preload member 58 exerts a force on the annular link 56 towards the side with the connecting part 50.

[0055] The cam 60 is arranged coaxially around the annular link 56. The cam 60 is rotatably supported by the housing 16 about the axis of the annular link 56. More specifically, the cam 60 is connected to a cylindrical section 16D, which extends from the end of the housing 16 on the side with the front sprocket S (relative to Fig. 1) with respect to the axial direction of the transmission shaft 26. The cam 60 comprises a cam surface 60A and a gear 60E. The cam 60 is designed in an annular shape.

[0056] As in the Fig. 6 and Fig. As shown in Figure 7, the cam surface 60A is formed on the side surface section of the cam 60 on the side with the ring gear 42 with respect to the axial direction of the transmission shaft 26. The cam surface 60A comprises inclined sections 60B, first flat sections 60C, and second flat sections 60D. The inclined sections 60B face the side of the connecting part 50 (right side in Figure 7). Fig. 7) inclined towards a circumferential direction. The first flat sections 60C and the second flat sections 60D are continuous with each of the second ends of the inclined sections 60B in the circumferential direction and are perpendicular to the transmission shaft 26. The first flat sections 60C are arranged in a position of the cam 60 that is closer to the side with the ring gear 42 than the second flat sections 60D with respect to the axial direction of the transmission shaft 26.

[0057] As in Fig. As shown in Figure 6, the coupling body 62 comprises an annular section 62A and a plurality of actuating elements 62B. The actuating element 62B extends radially from the annular section 62A. The annular section 62A is in contact with the projection 56E of the annular link 56 on the opposite side of the ring gear 42. The actuating elements 62B are provided in the circumferential direction of the annular section 62A. Here, as in Fig. As shown in Figure 1, two of the actuators 62B are provided in symmetrical positions with respect to the central axis C. As shown in Figure 1. Fig. As shown in Figure 6, the actuating elements 62B of the coupling body 62 contact the cam surface 60A in the axial direction of the transmission shaft 26. The actuating elements 62B of the coupling body 62 are fitted into the grooves 16C of the housing 16, which extend in the axial direction of the transmission shaft 26, in the circumferential direction of the cam 60. The coupling body 62 can be moved along the grooves 16C in the axial direction of the transmission shaft 26.

[0058] The actuator 64 is arranged radially outward from the cam 60. The actuator 64 is connected to the gear 60E of the cam 60. The actuator 64 rotates the cam 60 at a predetermined angle. A projection (not shown) is formed in the inner peripheral part of the cam 60. The projection (not shown) is inserted into a hole (not shown) formed in the cylindrical section 16D of the housing 16. The rotation angle of the cam 60 is limited by the end face of the hole (not shown) in the circumferential direction.

[0059] The operation of the switching mechanism 20 is described below with reference to the Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10 to Fig. 11 explained.

[0060] As in the Fig. 6 and Fig. Figure 7 shows that when the rotational phase of the cam 60 is in a phase in which the first flat sections 60C of the cam surface 60A and the actuating elements 62B of the coupling body 62 are in contact, the annular link 56 is held in a position on the side with the ring gear 42 via the coupling body 62. At this point, the grooves 56B of the annular link 56 are separated from the pawl links 54. For this reason, the pawl links 54 are held in the projecting positions, which face the grooves 16C formed in the opposite section 16A of the housing 16. Therefore, the pawl links 54 cannot rotate relative to the housing 16. The pawl links 54 are supported by the transmission shaft 26 such that they are not rotatable relative to the retaining element 44. For this reason, the pawl links 54 limit or restrict the rotation of the transmission shaft 26 and the sun gear 36 (see Fig. 1) in one direction.

[0061] As in the Fig. 8 and Fig. Figure 9 shows that when the rotational phase of the cam 60 transitions from a phase in which the first planar sections 60C of the cam surface 60A and the actuating elements 62B of the coupling body 62 are in contact, to a phase in which the second planar sections 60D of the cam surface 60A and the actuating elements 62B of the coupling body 62 are in contact, the pawl links 54 are guided in their projecting positions along the first guide surfaces 56C to the second guide surfaces 56D, accompanied by the rotation of the annular link 56 in one direction (the arrow direction RA in Fig. 10). More specifically, the latch elements 54 move from the shallow section to the deep section of the first guide surfaces 56. At this point, as in Fig. As can be seen in Figure 9, the ring-shaped link 56 is held in a position on the side of the connecting part 50 via the coupling body 62.

[0062] Subsequently, as the rear surfaces of the latch links 54 contact the second guide surfaces 56D and the annular link 56 continues to rotate, the latch links 54 are pressed towards the grooves 44A along the second guide surfaces 56D. This means that the annular link 56 of the control unit 52 presses the latch links 54 of the connecting part 50 and moves them from the projecting positions to the retracted positions. The latch links 54 will be in a state where they are pressed through the inner peripheral surface 56F of the annular link 56 of the connecting part 50; therefore, the latch links 54 are received in the retracted positions in the grooves 44A of the retaining link 44, as shown in Fig. As shown in Figure 11, the pawl links 54 are held in place. Therefore, they are able to rotate relative to the housing 16. The pawl links 54 are supported by the transmission shaft 26 in such a way that they are not rotatable relative to the retaining element 44. For this reason, the pawl links 54 do not restrict or limit the rotation in any direction of the transmission shaft 26 and the sun gear 36, which is not rotatable relative to the transmission shaft 26.

[0063] The one-way coupling 48, as in Fig. Figure 1 shows a roller coupling. The one-way coupling 48 is provided between the carrier 40 and the ring gear 42. The one-way coupling 48 rotates integrally with the carrier 40 and the ring gear 42 when the rotational speed of the carrier 40 in one direction is equal to or greater than the rotational speed of the ring gear 42. The one-way coupling 48 allows relative rotation between the carrier 40 and the ring gear 42 when the rotational speed of the carrier 40 in one direction is less than the rotational speed of the ring gear 42 in one direction. During this time, the rotation of the carrier 40 and the ring gear 42 in one direction corresponds to the direction of rotation of the input drive shaft 12 when the bicycle (not shown) moves forward.

[0064] The gear shift state of the bicycle drive unit 10 will now be described.

[0065] When the pawl links 54 are in their projecting positions, the rotation of the sun gear 36 relative to the housing 16 is limited. Therefore, when rotation is applied to the carrier 40, the planet gear 38 orbits the sun gear 36, which is rotated in the same direction as its orbit by the reaction force generated by the sun gear 36. As the planet gear 38 rotates, the ring gear 42 is forced into the direction of rotation of the planet gear 38, and the ring gear 42 is rotated in the same direction as the carrier 40. At this point, the rotation applied to the carrier 40 is accelerated and output by the ring gear 42.

[0066] When the pawl links 54 are in the retracted positions, the rotation of the sun gear 36 relative to the housing 16 is unrestricted. Therefore, if rotation is applied to the carrier 40, the planet gears 38 will rotate the sun gear 36 and cannot transmit the rotation to the ring gear 42. As a result, the rotational speed of the carrier 40 in one direction will be equal to or greater than the rotational speed of the ring gear 42. Consequently, relative rotation between the carrier 40 and the ring gear 42 is restricted, and the carrier 40 and the ring gear 42 rotate integrally via the one-way clutch 48. Furthermore, at this point, since the sun gear 36 is pushed by the planet gears 38 in the same direction as the carrier 40 and the ring gear 42, the sun gear 36 also rotates integrally with the carrier 40 and the ring gear 42. In other words, the one-way clutch 48 controls the rotation of the sun gear 36.

[0067] The assistance mechanism 22 comprises an assistance motor 66 and a deceleration mechanism 68 or deceleration mechanism or braking mechanism or slowing mechanism.

[0068] The auxiliary motor 66 is arranged radially outside the input rotating shaft 12. The auxiliary motor 66 is connected to the power transmission path from the input rotating shaft 12 to the output part 14. The output shaft 66A of the auxiliary motor 66 is arranged parallel to the input rotating shaft 12.

[0069] The deceleration mechanism 68, or deceleration mechanism, or slowing mechanism comprises a first reduction gear 70, a second reduction gear 72, a one-way coupling 74, and a third reduction gear 76.

[0070] The first reduction gear 70 has a cylindrical shape. Since the first reduction gear 70 is connected to the output shaft 66A of the auxiliary motor 66, the rotation of the auxiliary motor 66 is applied to the first reduction gear 70.

[0071] The second reduction gear 72 is arranged coaxially with the first reduction gear 70. The second reduction gear 72 is connected to the first reduction gear 70 via the one-way coupling 74. The second reduction gear 72 includes a support section 72A for supporting the first reduction gear 70 and the one-way coupling 74 at the outer peripheral part of the support section 72A. The two opposing axial ends of the second reduction gear 72 are rotatably supported by the housing 16 via a bearing or similar device.

[0072] The one-way coupling 74 transmits the rotation in one direction from the first reduction gear 70 to the second reduction gear 72 and does not transmit the rotation in the other direction from the second reduction gear 72 to the first reduction gear 70.

[0073] The second reduction gear 72 is connected to the third reduction gear 76. The rotation of the second reduction gear 72 in one direction is transmitted to the third reduction gear 76. The two opposing axial ends of the third reduction gear 76 are rotatably supported by the housing 16 via a bearing or similar device.

[0074] The third reduction gear 76 is connected to the first gear 42C of the ring gear 42. Therefore, the torque of the assist motor 66 is decelerated, slowed down, braked, or delayed by the deceleration mechanism 68 and applied to the ring gear 42.

[0075] The control unit 24 drives the assist motor 66 according to the muscle force applied to the input rotating shaft 12. The control unit 24 is housed within the casing 16. The control unit 24 comprises a printed circuit board. The main surface of the circuit board is oriented perpendicular to the input rotating shaft 12. The muscle force is detected, for example, by a torque sensor 78, which is attached to the input rotating shaft 12 or the transmission mechanism 18.

[0076] As in Fig. As shown in Figure 1, the torque sensor 78 is located in the vicinity of the bearing 17D, which supports one end of the transmission shaft 26. The torque sensor 78 is located at the input end of the transmission shaft 26. As shown in Fig. As shown in Figure 12, the torque sensor 78 is designed comprising a load cell 78A, a pair of support members 78B, a strain gauge 78C, and a press member 78F.

[0077] The load cell 78A has a cuboid shape. The load cell 78A is arranged such that its longitudinal direction is parallel to a tangential direction of an outer ring 17G. One side surface of the load cell 78A contacts the outer periphery of the outer ring 17G of the bearing 17D. The support members 78B support the load cell 78A from the side opposite where the load cell 78A contacts the bearing 17D. The support members 78B are provided at both ends of the load cell 78A in the longitudinal direction.

[0078] Each of the support members 78B has a columnar shape. The support members 78B are arranged such that their axes are perpendicular to the longitudinal direction of the load cell 78A. The support members 78B are also arranged such that their outer periphery contacts the load cell 78A. The load cell 78A and the support members 78B are provided at the recess 16E of the housing 16. The support members 78B are fixed to the recess 16E, while the load cell 78A is provided so as to be slightly movable within the recess 16E. The contact position between the outer periphery of the outer ring 17G of the bearing 17D and the load cell 78A is essentially the same as the midpoint between the support members 78B in the longitudinal direction of the load cell 78A. The load cell 78A is supported by the recess 16E, such that the load cell 78A can be easily deflected between the support members 78B.The load cell 78A is provided on the housing 16 such that the position in which the load cell 78A and the outer ring 17G of the bearing 17D are in contact is in the direction of the reaction force of the second transmission gear 34 or is slightly offset from this reaction force direction.

[0079] The bearing 17D is provided inserted in the recess 16E. The recess 16E is slightly larger than the bearing 17D, and the bearing 17D is designed to move slightly in a direction perpendicular to the central axis C (see Fig. 1) to be movable in the recess 16E. The bearing 17D presses the load cell 78A via the press member 78F. The press member 78F is, for example, formed from a diaphragm spring. The strain gauge 78C is provided on the side surface of the load cell 78A on the side opposite the side surface that contacts the bearing 17D, i.e., on the side surface that contacts the support member 78B.

[0080] The strain gauge 78C is implemented using a strain gauge, a semiconductor sensor, or a similar device. The load cell 78A is further equipped with a plurality of strain gauges 78D. Two of the strain gauges 78D have a detection characteristic in a direction parallel to the longitudinal direction of the load cell 78A, located near the center of the load cell 78A in the longitudinal direction, and two of the strain gauges 78D have a detection characteristic in a direction perpendicular to the longitudinal direction of the load cell 78A. For example, four strain gauges 78D are arranged symmetrically with respect to the center of the load cell 78A in the longitudinal direction. Two strain gauges 78D are arranged near the center of the load cell 78A in the longitudinal direction at one end.The other two strain gauges 78D are positioned near the center of the load cell 78A along its length at the opposite end. The detection directions of the four strain gauges 78D are one parallel and one perpendicular to the longitudinal direction of the load cell 78A. A bridge circuit is formed from the four strain gauges 78D to detect the strain generated in the load cell 78A.

[0081] An amplification device 78E is provided in the vicinity of the load cell 78A. The amplification device 78E amplifies a signal output from a strain gauge 78C. The amplification device 78E is provided in the recess 16E. The amplification device 78E outputs an amplified signal to the control unit 24 (see Fig. 1) out.

[0082] As in Fig. As can be seen in Figure 13, a shielding plate 79 covers the opening of the recess 16E, into which the load cell 78A, the support member 78B, and the reinforcement device 78E are provided. The shielding plate 79 is made of metal. A spring element 79A is formed on the shielding plate 79. The spring element 79A prevents the load cell 78A from moving towards the opening side of the recess 16E.

[0083] When the torque sensor 78 detects a torque equal to or greater than a predetermined torque, the control unit 24, shown in Fig. 1. The assist motor 66 is activated according to the torque detected by the torque sensor 78. The control unit 24 controls the actuator 64. The control unit 24 is connected to a switching unit (not shown) and drives the actuator 64 based on the signal from the switching unit. The switching unit consists of a switch and a lever located on the bicycle's handlebars. The switching unit can be connected to the control unit 24 via electrical wiring or wirelessly. The control unit 24 can operate the actuator 64 based on, for example, a detection signal from a sensor located on the bicycle. Examples of sensors include a speed sensor to detect the bicycle's speed and a cadence sensor to detect the pedaling cadence.With the control unit 24, which drives the actuator 64, the bicycle drive unit 10 serves or functions as a two-stage transmission device.

[0084] The power transmission path or power transmission route of the bicycle drive unit 10 is now described.

[0085] The auxiliary motor 66 is coupled to the ring gear 42. At least one part of the shifting mechanism 20 is coupled to the transmission path between the auxiliary motor 66 and the output part 14. Therefore, when the auxiliary motor 66 is driven, its torque is added to the torque transmitted to the annular link 68. Accordingly, the control unit 52 moves the pawl links 54 of the connecting part 50 from the protruding position to the retracted position using the muscle driving force and the torque of the auxiliary motor 66. That is, the shifting mechanism 20 can change the gear position of the transmission mechanism 18 using the torque of the auxiliary motor 66.Furthermore, if the assistance motor 66 is not driven, the control unit 52 can move the latch links 54 of the connecting part 50 from the protruding position to the entered position using only muscle power.

[0086] The bicycle drive unit 10 exerts the following effects.

[0087] (1) The shifting mechanism 20 can switch the gear position of the transmission mechanism 18 using the torque of the assist motor 66. Accordingly, the shifting performance can be improved compared to when the assist motor 66 is coupled downstream of the transmission mechanism 18.

[0088] (2) The switching mechanism 20 includes the one-way clutch 48. Accordingly, for example, the configuration of the bicycle drive unit 10 can be simplified compared to when the rotation of the sun wheel 36 is controlled by a motor.

[0089] A bicycle drive unit according to a second embodiment is described with reference to the Fig. 14 and Fig. 15 described. The configurations of the second embodiment that are identical to those of the first embodiment are provided with the same reference numerals, and the same descriptions thereof are omitted.

[0090] As in Fig. As shown in Figure 14, the bicycle drive unit 10 comprises the input rotary shaft 12, the output part 14, the housing 16, the assist mechanism 22, a transmission mechanism 80 and a shifting mechanism 82.

[0091] The transmission mechanism 80 comprises a transmission shaft 84, a transmission body 86, a first rotating body 88, a second rotating body 90, a third rotating body 92 and a fourth rotating body 94.

[0092] The transmission shaft 84 is arranged radially outside the input rotating shaft 12 and parallel to the input rotating shaft 12. The transmission shaft 84 is rotatably supported by the housing 16. The transmission shaft 84 is rotatable about a central axis C, the position of which does not change with respect to the input rotating shaft 12.

[0093] The transmission body 86 is designed in a tubular shape. The transmission body 86 is arranged coaxially around the input rotating shaft 12. The transmission body 86 is supported by the input rotating shaft 12 via a spline connection, a press fit, or similar connection, such that the input shaft is not rotatable relative to the shaft. For this reason, the transmission body 86 is integrally rotatable with the input rotating shaft 12.

[0094] The first rotating body 88 has a cylindrical shape, and one end of it in the axial direction is fitted to or adapted to the transmission body 86. This means that the transmission body 86 connects the input rotating shaft 12 and the first rotating body 88. A gear 88A is formed on the outer periphery of the first rotating body 88.

[0095] The second rotating body 90 is arranged coaxially around the transmission shaft 84. The second rotating body 90 is supported by the transmission shaft 84 via a spline connection, a press fit, or similar, such that it is not relatively rotatable. For this reason, the second rotating body 90 can be rotated integrally with the transmission shaft 84 about the central axis C. A gear 90A is formed on the outer periphery of the second rotating body 90. The gear 90A meshes with the gear 88A of the first rotating body 88. Therefore, the torque is transmitted from the first body 88 to the second rotating body 90 via the transmission body 86. The number of teeth of the gear 90A of the second rotating body 90 is less than the number of teeth of the gear 88A of the first rotating body 88.For this reason, the rotation of the first rotating body 88 is accelerated and transferred to the second rotating body 90.

[0096] The third rotating body 92 has a cylindrical shape. The third rotating body 92 is arranged around the transmission shaft 84. The third rotating body 92 is supported by the transmission shaft 84 via the switching mechanism 82. The third rotating body 92 can be rotatably supported by the transmission shaft 84. The third rotating body 92 is integrally connected to the second rotating body 90 and the transmission shaft 84, and rotatably encompasses the central axis C when connected to the transmission shaft 84 via the switching mechanism 82. The inner periphery of the third rotating body 92 has a plurality of grooves 92B. The grooves 92B are connected to the switching mechanism 82. A gear 92A is formed on the outer periphery of the third rotating body 92.

[0097] The fourth rotating body 94 has a cylindrical shape. The fourth rotating body 94 is arranged coaxially with the output part 14. The fourth rotating body 94 is connected to the output part 14 via a spline connection, a press fit, or a similar connection. Therefore, the fourth rotating body 94 can rotate integrally with the output part 14. A gear 94A is formed on the outer periphery of the fourth rotating body 94. The gear 94A meshes with the gear 92A of the third rotating body 92. Therefore, the torque is transmitted from the third rotating body 92 to the fourth rotating body 94. The number of teeth on gear 94A of the fourth rotating body 94 is less than the number of teeth on gear 92A of the third rotating body 92. For this reason, the rotation of the third rotating body 92 is decelerated or slowed down.The rotation is delayed to a predetermined speed reduction ratio and transmitted to the fourth rotating body 94. The speed increase ratio between the first rotating body 88 and the second rotating body 90 is greater than the predetermined speed reduction ratio between the third rotating body 92 and the fourth rotating body 94. Therefore, when the rotation is transmitted from the first rotating body 88 to the fourth rotating body 94 via the second rotating body 90 and the third rotating body 92, the rotational speed of the fourth rotating body 94 is greater than that of the first rotating body 88.

[0098] The switching mechanism 82 switches between a first state and a second state. The first state is a state in which the output part 14 and the input rotating shaft 12 are coupled via the transmission mechanism 80. The second state is a state in which the output part 14 and the input rotating shaft 12 are coupled without the transmission mechanism 80.

[0099] In the first state, the switching mechanism 82 allows torque to be transmitted between the input rotating shaft 12 and the first rotating body 88, between the first rotating body 88 and the second rotating body 90, between the second rotating body 90 and the third rotating body 92, between the third rotating body 92 and the fourth rotating body 94, and between the fourth rotating body 94 and the output part 14. In the second state, the switching mechanism 82 does not allow torque to be transmitted between the second rotating body 90 and the third rotating body 92.

[0100] The switching mechanism 82 comprises the control unit 52, the cam 60, the actuator 94, and a one-way clutch 96. The control unit 52 is arranged between the transmission shaft 84 and the inner periphery of the third rotating body 92. The cam 60 is provided for actuating the control unit 52. The actuator 64 is provided for actuating the cam 60. The one-way clutch 96 is arranged between the inner periphery of the transmission mechanism 28 and the outer periphery of the output part 14.

[0101] The control unit 52 comprises a connecting part 50, at least one part which is arranged between the outer periphery of the transmission shaft 84 and the inner periphery of the third rotating body 92, and an annular link 56.

[0102] The connecting part 50 is provided at the outer periphery of the transmission shaft 84. The connecting part 50 can couple the transmission shaft 84 and the third rotating body 92. The connecting part 50 comprises the latching elements 54, which project from the transmission shaft 84 towards the inner periphery of the third rotating body 92.

[0103] The annular link 56 has a cylindrical shape. The annular link 56 is positioned coaxially around the transmission shaft 84. The annular link 56 can be moved in the axial direction of the transmission shaft 84.

[0104] The one-way coupling 96 is a roller coupling. The one-way coupling 96 rotates integrally the input rotating shaft 12 and the output part 14 when the rotational speed of the input rotating shaft 12 in one direction is greater than or equal to the rotational speed of the output part 14 in that direction. The one-way coupling 96 allows relative rotation between the input rotating shaft 12 and the output part 14 when the rotational speed of the input rotating shaft 12 in one direction is less than the rotational speed of the output part 14 in that direction. The rotation in one direction corresponds to the direction of rotation of the input rotating shaft 12 when the bicycle (not shown) is moving forward.

[0105] When the annular link 56 moves laterally away from the connecting part 50 in the axial direction of the transmission shaft 84 into a position away from the connecting part 50, the grooves 56B are disengaged from the pawl links 54, and the pawl links 54 move into the projecting positions that extend towards the grooves 92B of the third rotating body 92. In other words, when the transmission mechanism 80 is in a first state, or in a first stage, the grooves 56B are disengaged from the pawl links 54, and the pawl links 54 move into the projecting positions that extend towards the grooves 92B of the third rotating body 92. As a result, the pawl links 54 are engaged in the grooves 92B. For this reason, the third rotating body 92 is not relatively rotatable with respect to the transmission shaft 84 and the second rotating body 90.For this reason, the torque of the transmission shaft 84 and the second rotating body 90 is transferred to the third rotating body 92.

[0106] The number of teeth of gear 88A of the first rotating body 88 is less than the number of teeth of gear 94A of the fourth rotating body 94. For this reason, when the switching mechanism 82 is in a state shown in Fig. 14, the rotation input to the transmission mechanism 80 is accelerated and output to the output part 14. When the switching mechanism 82 is in its first state, the rotational speed of the input rotating shaft 12 and the first rotating body 88 is lower than the rotational speed of the output part 14. For this reason, the one-way coupling 96 allows relative rotation between the input rotating shaft 12 and the first rotating body 88 and the output part 14. As a result, the rotation of the input rotating shaft 12 is accelerated by the transmission mechanism 80 and output to the output part 14.

[0107] As in Fig. As shown in Figure 15, when the annular link 56 moves towards the side approaching the connecting part 50 in the axial direction of the transmission shaft 84 and is in a position that is in contact with the connecting part 50, i.e., when the transmission mechanism 80 is in the second state, the grooves 56B press the pawl links 54 downwards. The pawl link 54 is thereby moved into a retracted position, which is retracted from the groove 92B of the third rotating body 92. This means that the annular link 56 releases the connecting part 50 from the third rotating body 92. For this reason, the third rotating body 92 becomes rotatable relative to the transmission shaft 84 and the second rotating body 90. For this reason, the torque of the transmission shaft 84 and the second rotating body 90 is not transmitted to the third rotating body 92.

[0108] When the switching mechanism 82 is in the second state, as shown in Fig. When the switching mechanism 82 is in position 15, the torque from the second rotating body 90 to the third rotating body 92 is not transmitted. Therefore, when the switching mechanism 82 is in the second state, the rotational speed of the input rotating shaft 12 and the first rotating body 88 is greater than or equal to the rotational speed of the output part 14. Consequently, the one-way clutch 96 integrally rotates the input rotating shaft 12, the first rotating body 88, and the output part 14. Therefore, the rotation of the input rotating shaft 12 is transmitted to the output part 14 without being accelerated by the transmission mechanism 80.

[0109] The assistance mechanism 22 includes an assistance motor 66. The gear of the output shaft 66A of the assistance motor 66 meshes with the gear 90A of the second rotating body 90. The rotation of the assistance motor 66 is transmitted to the second rotating body 90.

[0110] The torque sensor 98 is attached to the transmission body 86. The torque sensor 98 outputs a signal corresponding to the amount of torque applied to the transmission body 86 to the control unit 24. The control unit 24 controls the auxiliary motor 66 based on the output of the torque sensor 98. The torque sensor 98 is implemented, for example, by a strain gauge. The signal from the strain gauge is transmitted to the control unit 24 via a wired or wireless connection.

[0111] The bicycle drive unit 10 exerts the following effects.

[0112] (1) The shifting mechanism 82 can change the gear position of the transmission mechanism 80 using the torque of the assist motor 66. Accordingly, the shifting performance can be improved compared to when the assist motor 66 is coupled downstream of the transmission mechanism 80.

[0113] (2) The connecting part 50 is positioned between the third rotating body 92 and the transmission shaft 84 after the rotation of the input rotating shaft 12 has been accelerated. This means that the amount of torque applied to the connecting part 50 is less than the amount of torque applied to the input rotating shaft 12. Therefore, when the transmission mechanism 80 is in the first state and the pawl 54 of the connecting part 50 is engaged in the groove 92B of the third rotating body 92, the amount of force required to disengage the pawl 54 from the groove 92B can be reduced. The switching mechanism 20 switches the transmission of torque between the third rotating body 92 and the transmission shaft 84, which has a higher rotational speed and lower torque than the input rotating shaft 12.For this reason, the transmission performance can be improved compared to when the transmission of torque between the links is switched after the rotation of the input rotating shaft 12 has been decelerated or slowed down or braked or delayed.

[0114] (3) The switching mechanism 20 includes the one-way clutch 96. For this reason, for example, the configuration of the bicycle drive unit 10 can be simplified compared to when, for example, an electric clutch is provided and the transmission of torque between the output part 14 and the input rotating shaft 12 or the first rotating body 88 is controlled.

[0115] (4) The auxiliary motor 66 transmits the torque to the fourth rotating body 94. For this reason, the amount of torque applied to the connecting part 50 can be reduced compared to when the torque of the auxiliary motor 66 is transmitted upstream of the fourth rotating body 94 along the power transmission path from the input rotating shaft 12 to the output part 14. As a result, the transmission power reduced by the torque from the auxiliary motor 66 can be suppressed.

[0116] The specific shape that the bicycle drive unit takes is not limited to the shapes illustrated in the embodiments described above. The bicycle drive unit can take on different shapes from those described above. The modified examples of the embodiments described above, as explained below, are examples of different shapes that the bicycle drive unit can take.

[0117] • The auxiliary motor 66 of the first embodiment can be connected to the carrier 40 or the input rotating shaft 12 via the reduction mechanism 68. In short, the torque of the motor 66 can be transmitted to any rotating body 94, as long as the rotating body is located downstream of the ring gear 42, to which the annular element 56 of the switching mechanism 20 is coupled, on the power transmission path from the input rotating shaft 12 to the output part 14.

[0118] • The connecting part 50 of the first embodiment can be provided on the opposite section 16A. In this case, the grooves 56B are formed on the outer periphery of the annular element 56. Furthermore, the switching mechanism 20 moves the pawl elements 54 between the projecting positions, which extend into the grooves formed on the outer periphery of the transmission shaft 26, and the retracted positions, which are retracted from the grooves formed on the outer periphery of the transmission shaft 26.

[0119] • The planetary gear mechanism 30 of the first embodiment can be modified as explained below under (A)-(E).

[0120] (A) The rotation of the input shaft 12 is input to the ring gear, which is an input element. The rotation of the carrier, which is an output element, is output to the output element 14. The rotation of the sun gear, which is a controlled rotating element and also a transmission element, is controlled by the switching mechanism.

[0121] (B) The rotation of the input shaft 12 is input to the carrier, which is an input body. The rotation of the sun gear, which is an output body, is output to the output part 14. The rotation of the ring gear, which is a rotating body to be controlled and is also a transmission body, is controlled by the switching mechanism.

[0122] (C) The rotation of the input shaft 12 is input to the sun gear, which is an input element. The rotation of the carrier, which is an output element, is output to the output element 14. The rotation of the ring gear, which is a controlling rotating element and also a transmission element, is controlled by the switching mechanism.

[0123] (D) The rotation of the input shaft 12 is input to the sun gear, which is an input element. The rotation of the ring gear, which is an output element, is output to the output element 14. The rotation of the carrier, which is a rotating element to be controlled and also a transmission element, is controlled by the switching mechanism.

[0124] (E) The rotation of the input rotating shaft 12 is input to the carrier, which is an input body. The rotation of the sun gear, which is an output body, is output to the output part 14. The rotation of the carrier, which is a controlling rotating body and also a transmission body, is controlled by the switching mechanism.

[0125] • The auxiliary motor 66 of the second embodiment can be connected to the first rotating body 88, the input rotating shaft 12, the transmission shaft 84, or the transmission shaft 84 via the reduction mechanism 68. In short, the torque of the motor 66 can be transmitted to the transmission shaft 84, to which the annular link 56 of the switching mechanism is / will be coupled, or to any rotating body located along the power transmission path from the input rotating shaft 12 to the output part 14, via the transmission shaft 84.

[0126] • The connecting part 50 of the second embodiment can be provided on the inner periphery of the third rotating body 92. In this case, the grooves 56B of the annular member 56 are configured to hold the connecting part 50 downwards and radially outwards. Furthermore, the switching mechanism 82 moves the pawl members 54 between the projecting positions, which extend into grooves formed on the outer periphery of the transmission shaft 84, and the retracted positions, which are retracted from the grooves formed on the outer periphery of the transmission shaft 26.

[0127] • The transmission mechanism 80 of the second embodiment can be modified into a transmission mechanism that decelerates, slows down, or decelerates the rotation input to the input rotating shaft 12 and outputs it. In this case, the same switching mechanism as the switching mechanism 82 is provided between the first rotating body 88 and the output part 14 instead of the one-way clutch 96 to control the power transmission path.

[0128] • The one-way couplings 48 and 96 of the first and second embodiments can be a one-way coupling provided with a ratchet mechanism.

[0129] • A one-way clutch that prevents reverse rotation of the output part 14 can be provided on the bicycle drive unit 10 of the first and second embodiments. The one-way clutch can, for example, be provided between the input rotating shaft 12 and the transmission body (sun gear 36).

[0130] • The reduction mechanism 68 of the first and second embodiments can be omitted.

[0131] • The bicycle drive unit 10 of the first and second embodiments can be provided radially outside the crankshaft. In this case, a transmission mechanism is provided for inputting the rotation of the crankshaft to the input rotating shaft.

[0132] • The actuator 64 of the first and second embodiments can be omitted. In this case, the actuating device attached to the bicycle and the shifting mechanism 20 and 82 are connected by a cable or wire, and the cam 60 is actuated by actuating the wire. DESCRIPTION OF REFERENCE MARKS 10 bicycle drive unit 12 Input rotating shaft (crankshaft) 14 Starting part 14A Mounting section 16A opposite section 16C Nut 18 Transmission mechanism 20 shift mechanism 26 Transmission shaft (rotating body to be controlled, support element) 30 planetary gear mechanism 36 Sun wheel (transmission body) 38 planetary gear 40 carriers (rotating body) 42 Ring gear (output body, the other rotating body) 48 One-way coupling (roller coupling) 50 connecting part 52 Control unit 54 Latch link 56 ring-shaped link 56B Nut 60 cams 64 Actuator 66 Assist motor 80 Transmission mechanism 82 Shift mechanism 84 transmission wave 86 transmission bodies 88 first rotating body 90 second rotating body 92 third rotating body (rotating body to be controlled) 92B Nut 94 fourth rotating body 94A gear 96 One-way coupling

Claims

[1] Bicycle drive unit (10), comprising: an input rotary shaft (12); an output part (14); a transmission mechanism (18; 80) which comprises at least two switching stages and which can change the speed of a rotary input which is / is input by the input rotary shaft (12) and can output the rotary input to the output part (14); an assistance motor (66) which is / will be coupled to a power transmission path from the input rotating shaft (12) to the output part (14), and which is driven by a muscular force; and a shifting mechanism (20; 82) which can switch a gear shift state of the transmission mechanism (18; 80) using a rotational force of the assist motor (66), wherein the transmission mechanism (18; 80) comprises a planetary gear mechanism (30), and wherein the planetary gear mechanism (30) comprises an input body which is rotatably supported by a support member, and on which the rotary input of the input rotary shaft (12) is / is input; a starting body which is / is rotatably supported by the supporting member, and outputs the rotation input externally; and a transmission body (86), wherein the switching mechanism (20; 82) further comprises a one-way coupling (48; 96) which is provided between the input body and the output body and which controls a rotation of the transmission body (86). [2] Bicycle drive unit (10) according to claim 1, in which at least one part of the switching mechanism (20; 82) is coupled to the transmission path between the assist motor (66) and the output part (14). [3] Bicycle drive unit (10) according to claim 1 or 2, wherein the one-way coupling (48; 96) integrally rotates the input body and the output body when a rotational speed of the input body in one direction is equal to or greater than a rotational speed of the output body in one direction and allows a relative rotation between the input body and the output body when the rotational speed of the input body in one direction is less than the rotational speed of the output body in one direction. [4] Bicycle drive unit (10) according to one of claims 1 to 3, in which the support member can rotate integrally with the transmission body (86) and the switching mechanism (20; 82) comprises: a connecting part (50) which is arranged on the transmission body (86) or on a counter section (16A) which is opposite the transmission body (86) and is movable between a projecting position in which the rotation of the transmission body (86) is controlled in at least one direction, and a retracted position in which the rotation of the transmission body (86) is not controlled, and a control unit (52) which moves the connecting part (50) from the protruding position to the retracted position using the torque of the assist motor (66). [5] Bicycle drive unit (10) according to claim 4, in which the control unit (52) pushes the connecting part (50) and moves it from the protruding position to the retracted position. [6] Bicycle drive unit (10) according to claim 4 or 5, in which a plurality of connecting parts (50) is / is provided around a pivot axis of the support member. [7] Bicycle drive unit (10) according to one of claims 4-6, in which the control unit (52) comprises an annular member (56) which can be rotated integrally with the output body, and which comprises a groove which becomes flatter in a radial direction towards a circumferential direction, in a section opposite the connecting part (50). [8] Bicycle drive unit (10) according to one of claims 1-7, in which the assist motor (66) is / is connected to the output body or to an upstream side of the output body on the power transmission path. [9] Bicycle drive unit (10) according to one of claims 4-6, wherein the transmission body (86) comprises a sun wheel (36) which rotates integrally with the support member; the output body comprises a ring gear (42) which is / will be arranged coaxially around the sun gear (36); and the input body comprises a carrier (40) which is / will be arranged between the sun gear (36) and the ring gear (42), and which integrally rotates a plurality of planet gears (38). [10] Bicycle drive unit (10) according to claim 9, in which the connecting part (50) is / is provided on the support member. [11] Bicycle drive unit (10) according to claim 1 or 2, wherein the transmission mechanism (18; 80) comprises a plurality of rotating bodies, including a rotating body to be controlled, and the switching mechanism (20; 82) comprises: a connecting part (50) which is provided on the rotating body to be controlled, or on a counter section (16A) which is opposite the rotating body to be controlled, and which can be moved between a projecting position in which the rotation of the rotating body to be controlled is regulated in at least one direction, and a retracted position in which the rotation of the rotating body to be controlled is not regulated; and a control unit (52) which moves the connecting part (50) from the protruding position to the retracted position using the torque of the assist motor (66). [12] Bicycle drive unit (10) according to claim 11, in which the control unit (52) pushes the connecting part (50) and moves the connecting part (50) from the protruding position to the retracted position. [13] Bicycle drive unit (10) according to claim 11 or 12, in which a plurality of connecting parts (50) are provided around a rotation axis of the rotating body to be controlled. [14] Bicycle drive unit (10) according to one of claims 11 to 13, in which the control unit (52) comprises an annular member (56) which is integrally rotated with a further rotating body, other than the rotating body to be controlled, among the plurality of rotating bodies including the drive mechanism, and the annular body (56) comprises a groove which becomes flatter in a radial direction towards a circumferential direction in a section opposite the connecting part (50). [15] Bicycle drive unit (10) according to one of claims 11-14, in which the assist motor (66) is connected to another rotating body or to the power transmission path on the upstream side of the other rotating body. [16] Bicycle drive unit (10) according to claim 7 or 14, in which the annular member (56) presses the connecting part (50) radially inwards. [17] Bicycle drive unit (10) according to one of claims 4-7 or 11-14, wherein the connecting part (50) comprises a ratchet element (54). [18] Bicycle drive unit (10) according to claim 7 or 14, wherein the control unit (52) further comprises a cam (60) for moving the annular member (56) in a direction of rotation and an electric motor for driving the cam (60). [19] Bicycle drive unit (10) according to one of claims 1-18, wherein the input rotating shaft (12) is a crankshaft to which a muscle driving force is / is applied. [20] Bicycle drive unit (10) according to claim 19, in which the assist motor (66) is / will be arranged radially outwards from the crankshaft. [21] Bicycle drive unit (10), comprising: an input rotary shaft (12); an output part (14); a transmission mechanism (18; 80) which comprises at least two switching stages and which can change the speed of a rotary input which is / is input by the input rotary shaft (12) and can output the rotary input to the output part (14); an assistance motor (66) which is / will be coupled to a power transmission path from the input rotating shaft (12) to the output part (14), and which is driven by a muscular force; and a shifting mechanism (20; 82) which can shift a gear shift state of the transmission mechanism (18; 80) using a rotational force of the assist motor (66), wherein the transmission mechanism (18; 80) comprises: a first rotating body (88) which is rotated integrally with the input rotating shaft (12); a second rotating body (90), which is rotated integrally about a central axis whose position does not change with respect to the input rotating shaft (12), and to which a rotation of the first rotating body (88) is transmitted; a third rotating body (92) which is rotated integrally with the second rotating body (90); and a fourth rotating body (94) to which the rotational force of the third rotating body (92) is / is transferred, and which is rotated integrally with the original part (14); and the switching mechanism (20; 82) comprises: a connecting part (50) which is provided on a counter section (16A) which is opposite one of the second rotating body (90) and the third rotating body (92), and which is moved between a projecting position in which the rotation of one of the second rotating body (90) and the third rotating body (92) is regulated in at least one direction, and a retracted position in which a rotation of one of the second rotating body (90) and the third rotating body (92) is not regulated; and a control unit (52) which moves the connecting part (50) from the protruding position to the retracted position using the torque of the assist motor (66).

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