Bicycle equipped with a continuously variable transmission on the pedaling side, independent of a transmission for electric assistance.

Abstract

Electric and muscle-powered bicycle drive system: arranged at the bottom bracket; the electric power transmission has two reduction stages, the first by gears and the second by roller chain or toothed belt, and between the two stages, a clutch engagement, disengagement, and parking lock device connected to the rear wheel, without a freewheel, allowing the motor to be driven by the rear wheel and to operate as a generator; the muscle power transmission has a continuously variable ratio device with pulleys and a belt in a closed and lubricated environment, the ratio being determined by the position of a hydraulic cylinder acting on the driven pulley and the belt tension by a spring acting on the driving pulley. The two transmission paths are independent. Figure for the abbreviation: Fig. 7

Description

Title of the invention: Bicycle equipped with a continuously variable transmission on the pedaling side, independent of a transmission for electric assistance. TECHNICAL FIELD OF THE INVENTION

[0001] The present invention discloses a road bicycle equipped with a continuously variable ratio transmission, for muscular force, arranged at the level of the crankset.

[0002] The bicycle is also equipped with an electric powertrain (EPC) arranged at the bottom bracket.

[0003] The gmpe drives a dedicated transmission to the rear wheel, with two reduction stages between which is interposed a dog clutch device allowing the connection / disconnection of the motor as well as locking the bicycle in parking.

[0004] This transmission dedicated to the engine is without a freewheel, which makes it possible for the rear wheel to drive the motor which switches to generator mode, in other words electric braking with energy recovery.

[0005] The continuously variable ratio transmission associated with the crankset and that associated with the electric assistance group are independent. STATE OF THE ART

[0006] Bicycles with electric assistance, when the drive unit is arranged at the level of the crankset, are mostly equipped with a common drive of the rear wheel, for muscle power and for the electric motor, via a single chain.

[0007] The single or multiple chainrings of the crankset drive the rear wheel via the chain, then a single or multiple sprocket associated with a freewheel. Propelling the bicycle by the rear wheel is not possible.

[0008] The single transmission requires gear changes under chain tension if the electric assistance cannot be interrupted. This is detrimental to the durability of the entire drive system, and gear changes are rather uncomfortable.

[0009] This can be avoided by adopting a transmission dedicated to the drivetrain and in parallel with that of the crankset.

[0010] On mopeds with internal combustion engines, the two transmissions are, in the vast majority of cases, independent.

[0011] This solution is also known for electrically assisted bicycles. See, in particular, publications FR3067698 and FR3082180.

[0012] Energy recovery is active on all electric cars during braking and sometimes as soon as the accelerator pedal is released. This function is virtually non-existent on electric bicycles. In publication EP2921396A2, the assistance motor is located at the bottom bracket, and the transmission is shared with the crankset. The sprockets of the rear wheel drive it via a freewheel. For energy recovery, the freewheel is neutralized by a parallel clutch. The crankset is then driven by the wheel, which is not a comfortable situation.

[0013] Continuously variable transmission for bicycles is known but almost not applied commercially.

[0014] Publication WO2014 / 170061 discloses schematically a transmission (2) for an electrically assisted bicycle comprising a pulley (11, 12) and belt (13) drive. In the embodiment of [Fig. 2], the transmission includes an epicyclic gear train (15) acting as a common drive for the electric motor (3) and the bottom bracket shaft (20): the motor (3) is connected to the ring gear (17), while the bottom bracket shaft drives the planet carrier (18) via the drive (11, 12, 13). The planetary gear (13) is the single output to the sprocket (4). The drive ratio control mechanism for the pulley drive is electromechanical and comprises a motor (62), a screw (63), and levers.

[0015] Publication WO2009 / 031797 discloses a semi-spherical variator.

[0016] Publication US2016 / 0040763 discloses an electrically assisted bicycle whose motor is linked to the bottom bracket shaft via a variator with spherical satellites. PRESENTATION OF THE INVENTION

[0017] The bicycle is equipped with an electric powertrain consisting of a direct current or alternating current motor, synchronous or asynchronous, and a two-stage reducer, the first stage of which includes a driving pinion and a driven pinion, with helical or straight teeth, arranged in a sealed compartment containing a liquid lubricant, and the second stage includes a driving toothed wheel arranged in the axis of the crankset, but independent of it, and a driven wheel arranged in the axis of the rear wheel, and linked by a roller chain or a toothed belt.

[0018] A hollow shaft, mounted on a needle bearing, partially surrounds the bottom bracket shaft, carries the second-stage drive gear, guides the first-stage driven sprocket mounted on a smooth ring, and carries a fixed hub. A sliding splined sleeve allows the driven sprocket to be coupled to and decoupled from the fixed hub, and thus from the electric motor to the rear wheel.

[0019] The driven pinion of the second stage is of the fixed type with respect to the axis of the rear wheel, which allows a flow of power from the wheel to the electric motor which then operates as a generator.

[0020] The motor connection sliding sleeve has axial teeth on one of its sides.

[0021] The three-position electric motor connection sliding sleeve: • in the first one it is entirely supported by the driven pinion: the electric motor is disconnected; • in the second, central one, it is supported both by the driven pinion and the fixed hub: the motor is connected to the rear wheel with a possible power transmission in both directions; • in a third position, still supported by the driven pinion and the fixed hub, the axial teeth are engaged in a fixed toothing belonging to the gearbox housing.

[0022] This third position creates a lock of the engine, the rear wheel and acts as an anti-theft device.

[0023] The sleeve is moved by a fork whose sliding axis carries an arm equipped with a threaded hole cooperating with the threaded axis of a stepper motor control.

[0024] The locking-unlocking device is controlled by a computer and responds to the presence of an activation ignition key.

[0025] A pedal arm is attached to each end of the bottom bracket shaft. A second toothed chainring, located near the arm opposite the one near the toothed chainring driven exclusively by the electric motor, is driven exclusively by muscle power.

[0026] This exclusively muscle-powered chainring drives, via a chain or toothed belt, a single sprocket carried by the axle of the rear wheel. Due to the presence of a freewheel, the wheel can only be driven forwards.

[0027] The crankshaft drives the exclusive toothed chainring by muscular force via a continuously variable ratio device with pulleys and metal belt and a triplet of sprockets.

[0028] The variator includes a drive pulley carried and driven in rotation by the crankshaft.

[0029] The drive pulley is composed of two flanges with variable spacing, one carrying the other, joined in rotation by grooves, and pushed towards the belt by a suitably preloaded spring.

[0030] The drive pulley is axially free and its positioning is determined by the belt.

[0031] The driven pulley is carried by an intermediate shaft and free to rotate on the latter.

[0032] One of the flanges is axially supported on the gearbox housing by means of a ball thrust bearing.

[0033] The other flange carried by the first, is axially free and rotationally fixed by grooves.

[0034] An annular hydraulic chamber, via a second ball bearing, pushes the second flange towards the first flange and forces the belt into a variable radial position between the two flanges. The piston bears against the engine casing.

[0035] Depending on the position of the cylinder, the belt therefore moves radially while the opposite strand, on the driving pulley, moves in the opposite direction and positions the latter axially. The minimum radii Rm and maximum radii RM, identical on each pulley, define the range of variation which is equal to (RM / Rm)2.

[0036] The hydraulic chamber is supplied with pressurized fluid through a series of channels: in the gearbox housing, along the fixed intermediate shaft and in the annular piston.

[0037] On the second flange is fixed a driving gear which drives an intermediate sprocket which in turn drives a driven gear, in a ratio close to 1, carried by a hub free to rotate on the bottom bracket shaft. The presence of the intermediate sprocket ensures that the crankset and the wheel have identical directions of rotation for the transmission of muscular force.

[0038] This hub, guided in the engine casing by a bearing, carries and drives in rotation the toothed plate dedicated to muscular force. DETAILED DESCRIPTION OF THE INVENTION

[0039] These features, objectives and advantages of the present invention will become apparent from the detailed description that follows and from the accompanying drawings given by way of non-limiting examples and on which:

[0040] Fig. 1 is a cross-section defining the longitudinal sections A1-A2, A1-B, A1-C, A1-D and the angular positioning of the different devices constituting this double transmission of muscular force and electrical force.

[0041] The [Fig.2] is a cross-section defining the longitudinal section A1-A3, passing through the intermediate pinion of the triplet of return pinions from the intermediate shaft to the hub carrying the toothed plate dedicated to muscle power.

[0042] Fig. 3 is a longitudinal sectional view A1-A2 of the powertrain passing through the axis of the electric motor, the axis of the pedal assembly and the intermediate shaft of the continuously variable ratio device in a short ratio situation, focused on the description of the electric motor and the reducer.

[0043] Fig. 4 is a longitudinal cross-sectional view A1-D of the powertrain passing through the electric motor shaft, the crankshaft, the fork shaft, and the sliding sleeve control motor shaft, focusing on the description of the dog clutch mechanism. The sliding sleeve is in the dog clutch position.

[0044] Fig. 5 is a second longitudinal cross-sectional view A1-D of the powertrain passing through the electric motor shaft, the crankshaft, the fork shaft, and the sliding sleeve control motor shaft. The sliding sleeve is in the disengaged position.

[0045] Fig. 6 is a third longitudinal sectional view A1-D of the powertrain passing through the electric motor shaft, the crankshaft shaft, the fork shaft, and the sliding sleeve control motor shaft. The sliding sleeve is in the locked position.

[0046] Fig. 7 is a longitudinal sectional view A1-A3 of the powertrain passing through the electric motor shaft, the crankshaft shaft, the intermediate shaft and the intermediate pinion of the continuously variable ratio device in a high ratio situation and focused on the description of the continuously variable ratio device.

[0047] Fig. 8 is a combined longitudinal section view Al-B and Al-C of the powertrain passing through the electric motor shaft, the crankshaft shaft and the rotation speed sensors of the crankshaft shaft (pedaling speed) and the hollow shaft (bike speed).

[0048] Fig. 1 is a cross-section of the two-source powertrain. This section shows the longitudinal section A1-A2, the combined longitudinal sections Al-C and Al-B, and the longitudinal section Al-D.

[0049] The longitudinal section A1-A2 of the powertrain 10 passes through the shaft of the assist motor 20, the crankshaft 50, and the intermediate shaft 61 of the continuously variable ratio device 60 dedicated to muscle power. It shows the latter in the low ratio and its angular positioning.

[0050] The combined longitudinal sections Al-C and Al-B passing through the axis of the assist motor 20, the crankshaft 50 show the angular positions of the pedaling speed 110 and bicycle speed 112 sensors.

[0051] The longitudinal section Al-D passing through the axis of the assistance motor 20, the shaft 50 of the crankset and the complete device 40 for engaging, disengaging, locking the transmission dedicated to the electric motor 20 shows its angular positioning.

[0052] Finally, this cross-section shows the positioning of the filling plugs 100 and drain plugs 101, with integrated magnet 102, of a suitable fluid, both for lubrication and traction for the continuously variable ratio device 60, partially filling the sealed space containing the reducer 30, partially the dog clutch device 40, the continuously variable ratio device 60, and the crankshaft 50 carrying elements of the various devices 30, 40, 60.

[0053] Figure 2 is a cross-section of the two-source powertrain 10. This section shows the longitudinal section A1-A3 passing through the shaft of the assist motor 20, the bottom bracket shaft 50, the shaft of the intermediate sprocket 82, and the intermediate shaft 61 of the continuously variable ratio device 60 dedicated to muscle power. This figure shows the arrangement of the intermediate sprocket 81 and the continuously variable ratio device 60 in the high gear ratio.

[0054] Fig. 3 shows the powertrain 10 according to a longitudinal section A1-A2 passing through the shaft of the assist motor 20, the shaft 50 of the crankset and the intermediate shaft 61 of the continuously variable ratio device 60.

[0055] The motor 20, in the embodiment presented, is of the permanent magnet synchronous type. It is arranged in a motor housing 21, and consists of a wound stator 22 and a rotor 23 carried by a shaft 24.

[0056] The rotor shaft 24 is supported by the permanently lubricated and sealed ball bearings 25.

[0057] The speed control of the motor 20 is achieved using the resolver 26 (sensor of speed and angular position of the rotor shaft 24), arranged in the motor housing 21.

[0058] The engine compartment is closed by the housing 31 of the reducer 30.

[0059] At the end of the rotor shaft 24 is cut the teeth 24a which constitute the driving pinion of the reducer 30.

[0060] Between the electric motor 20 and the rear wheel (not shown) the mechanical link has two levels of reduction. The first is a reducer 30 consisting of a driving gear 24a and a driven pinion 34.

[0061] It is arranged in an enclosed space 30a consisting of a motor housing 21, a gearbox housing 31 and its cover 32.

[0062] This closed space 30a contains a suitable fluid, both lubricating and traction fluid for the continuously variable ratio device 60 introduced through the filling plug (see 100 on [Fig.l]) and discharged through the drain plug 101 with a cylindrical magnet 102 retaining the iron filings released during use (see 101 and 102 on [Fig.l]).

[0063] The driving gear 24a and the driven pinion 34 have spur or helical teeth. The reduction ratio is approximately 13.

[0064] In the bearing 34a of the driven pinion 34 is fitted a smooth ring 35. It is carried by a hollow shaft 36 with which it occasionally has a differential rotation speed.

[0065] The hollow shaft 36 guides the shaft 50 of the crankset. Between these two shafts 36 and 50, which have permanently different rotational speeds, a needle bearing 37 is inserted.

[0066] The hollow shaft 36 carries in the closed space 30a, in addition to the driven pinion 34, a dog clutch hub 41, driven in rotation by splines 36a and stopped by a ring, a target 113 of the bicycle speed sensor (see on [Fig.8]), a ball bearing 38 for its guidance and axial retention in the cover 32. It is stopped by a ring 33.

[0067] The crankshaft 50 is held axially by the hollow shaft 36 with clearance, by, on the left, a shoulder 50a, and on the right, a washer 51 and a stop ring 52.

[0068] The hollow shaft 36, on its grooved end 36b, outside the closed space 30a, carries a toothed wheel 39, stopped by a ring, driving the second stage reduction of the link of the electric motor 20 with the rear wheel (not shown).

[0069] Fig. 4 shows the drive unit 10 according to a cross-section A1-D passing through the shaft of the assist motor 20, the gear pair and pinion 24a, 34 of the reducer 30, the shaft 50 of the crankset, an axis 44 of an axial displacement fork 43 of the sliding sleeve 42 and the shaft of the stepper motor 46 of the device 40.

[0070] The driven pinion 34, on the outer area of ​​its bearing 34a which extends laterally beyond the teeth, has splines 34a 1. The hub 41 has splines 41 a1 on its outer periphery, identical to those of the pinion. On these splines 34 a1, 41 a1, a sleeve 42 slides axially, driven by the fork 43 to engage (dog clutch situation) or disengage (disengagement situation) the driven pinion 34 from the hub 4L

[0071] The shaft 44 of the fork 43 passes through the motor housing 21. On the outer part of the shaft 44, a perpendicular arm 45 with a threaded hole 45a is attached. A threaded shaft 46a passes through this arm. Rotating the shaft 46a of the stepper motor 46 in one direction and its opposite direction causes the fork to move from right to left and vice versa.

[0072] In this [Fig. 4], the sleeve 42 is partially supported by the splines 34al of the driven pinion 34 and the splines 41al of the hub 4L. The driven pinion 34 and the hub 41 are locked together in the so-called dog clutch position. The transmission line 49-1, continuous from the rotor 23 to the toothed wheel 39, shows that the motor 20 is locked to the rear wheel (not shown) of the bicycle.

[0073] The part of the actuator external to the closed space 30a (motor 46 and its shaft 46a, arm 45) is protected from the external environment by a cover 47.

[0074] Fig. 5 shows the drive unit 10 according to a second section A1-D passing through the shaft of the assist motor 20, the gear pair and pinion 24a, 34 of the reducer 30, the shaft 50 of the crankset, an axis 44 of an axial displacement fork 43 of the sliding sleeve 42 and the shaft of the stepper motor 46 of the device 40.

[0075] In this [Fig. 5], the sleeve 42 is entirely supported by the splines 34a 1 of the driven pinion 34 bearing 34a. The driven pinion 34 and the hub 41 are thus disengaged, in the so-called disengaged position. The transmission line 49-2, continuous from the rotor 23 to the sliding sleeve 42, and the transmission line 49-3 from the hub 41 to the toothed wheel 39, show that the motor 20 is disengaged from the rear wheel (not shown) of the bicycle.

[0076] Fig. 6 shows the powertrain 10 according to a third section Al-D passing through the shaft of the assist motor 20, the gear pair and pinion 24a, 34 of the reducer 30, the shaft 50 of the pedal assembly, an axis 44 of an axial displacement fork 43 of the sliding sleeve 42 and the shaft of the stepper motor 46 of the device 40.

[0077] The sleeve 42 has axial teeth 42a on one face, opposite the reduction housing 31. These teeth are engaged in notches 31a belonging to the reduction housing 31 and block the rotation of the sleeve 42.

[0078] The sleeve 42 is carried almost entirely by the splines 41al of the hub 4L II. It is important that it is also slightly carried by the splines 34a 1 of the bearing 34a of the driven pinion 34 in order to easily leave the blocking situation and move to the dog-engagement or dog-disengagement situation.

[0079] The transmission line 49-4 which goes from the notches 31a to the rear wheel via the toothed wheel 39, shows that the rear wheel (not shown) of the bicycle is locked in both directions of rotation (no freewheel on the rear wheel associated with the pinion of the transmission line of the electric motor 20).

[0080] The transmission line 49-5 which goes from the notches 31a to the rotor 23, shows that the motor 20 is also blocked.

[0081] This rear wheel lock in both directions of rotation has an anti-theft function.

[0082] Fig. 7 shows the powertrain 10 according to a longitudinal section Al-A3 passing through the shaft of the assist motor 20, the crankshaft 50, the shaft 82 of the intermediate sprocket 81 and the intermediate shaft 61 of the continuously variable ratio device 60 in a high ratio situation.

[0083] Muscular force is supplied to the pedals (not shown) arranged at the ends of arms 53, 54 which drive the bottom bracket shaft 50 via splines 50b, 50c. They are axially supported on the conical areas 50d and axially locked by screws 55.

[0084] The crankshaft 50 carries the drive pulley of the continuously variable ratio device 60 composed of two flanges 64,65.

[0085] The flange 64, driven in rotation by means of the splines 50c of the shaft 50, carries the second flange 65 and drives it in rotation by means of the splines 64a-65a. They are axially movable relative to each other.

[0086] A spring 66 pushes them towards each other, against a belt 63, and puts the belt under tension. It bears on one side on the flange 65 and on the other side on a washer 67 held in place by a ring 68 carried by the supporting flange 64.

[0087] The two flanges 64,65 and the pressure spring 66 form a free assembly axially positioned by the belt 63.

[0088] The intermediate shaft 61 is the support of the driven pulley composed of the carrier flange 70 and the carried flange 71. They are linked in rotation by the splines 70a-71a and are axially free with respect to each other.

[0089] The intermediate shaft is axially fixed, supported and resting on the housing 31 of the reducer 30 and the housing 21 of the motor 20. It is blocked in rotation relative to the housing 21 by the pin 76.

[0090] The flange 70 carried by the needle bearing 72 is free to rotate relative to the intermediate shaft 61, and relative to the housing 31 on which it rests by means of a ball bearing 73.

[0091] The flange 71 is subjected to an axial thrust from the cylinder 77, via a second ball bearing 74. Depending on the quantity of oil in the chamber 77a, the flange 71 moves closer (increasing the radius of action of the belt 63 and decreasing the ratio) or moves further away (reducing the radius of action of the belt 63 and increasing the ratio).

[0092] Simultaneously, the flanges 64,65 have an opposite movement and the pressure of the spring 66 ensures the tension of the strands of the belt 63.

[0093] The chamber 77a of the cylinder 77 is supplied with pressurized oil by a series of channels 31b and 31c in the housing 31, then the radial 61a, axial 61b and radial 61c channels in the intermediate shaft 61, and then radial 75a, axial 75b in the piston 75 closing the chamber 77a, supported on the housing 21 and stopped in rotation by the pin 76.

[0094] The channels are matched by means of the orientation pin 76: 31c with 61a and 61c with 75a. The sealing of these matches is achieved by the static seals 62 in pairs.

[0095] The channel network is supplied by a transmitter piston (not shown) with mechanical or electrical control operated by the cyclist.

[0096] The power and movement of the driven pulley is returned to the toothed plate 56 by the pinion triplet 80,81,85.

[0097] The driving pinion 80 is attached, for example by welding, to the driven flange 71.

[0098] The intermediate pinion 81 is carried by its shaft 82, by means of a needle bearing 83. The shaft 82 is fitted with a clamping and cantilevered in the bearing 21a of the motor housing 21. The shaft is stopped by a ring 84.

[0099] Since the pinion 80 is axially movable, the teeth are of the straight type.

[0100] The intermediate sprocket 81 is essential, in order to reverse the direction of rotation of the driven sprocket 85 and obtain the same direction of rotation for the crankset and the rear wheel receiving the muscular force.

[0101] The driven return pinion 85 is carried by the hub 86.

[0102] The hub 86 is supported by the housing 21, guided by the bearing 87. It supports and guides the crank arm 54, and crank shaft 50 via needle bearing 88.

[0103] The toothed plate 56 is centered on the hub 86 and driven in rotation by pins 89.

[0104] The transmission of muscular power from the arms 53,54 of the pedal assembly to the toothed chainring 56 to the rear wheel, via the continuously variable ratio device 60 is shown by the arrowed path 90, independent of the path attached to the electric motor.

[0105] Figure [Fig. 8] shows the powertrain 10 in a double longitudinal section Al-B and Al-C passing through the motor shaft 20 of the assistance, the crankshaft shaft 50 and the two pedaling speed sensors 110 and the bicycle speed sensor 112.

[0106] The speed sensor 110 arranged on the engine casing 21 of the engine 20, has as its reading track the notches 11 la of the target 111 reported on the flange 65 of the drive pulley of the continuously variable ratio device 60. This information allows the computer (not shown) to efficiently manage the level of assistance or electric braking.

[0107] The bicycle speed sensor 112 arranged on the cover 32, has as its reading track notches 113a cut into a target 113. This target is carried by the hollow shaft 36 in permanent connection with the rear wheel without freewheel (not shown) via the driving toothed wheel 39.

[0108] The bicycle's speed sensor 112 provides information that allows the computer to efficiently manage the level of electric assistance or braking. Furthermore, this information is essential for the computer to control the motor 20 at the near-synchronization speed of the driven sprocket 34 with the hub 41, enabling rapid and quiet engagement.

[0109] Fig. 8 also shows the various seals required for proper sealing. operation and durability of the reducer 30 and the continuously variable ratio device 60.

[0110] The dynamic seal 120 ensures the sealing of the reducer 30 vis-à-vis the engine compartment 20, the dynamic seals 121 and 122 the sealing of the reducer 30 vis-à-vis the outside at the passage of the hollow shaft 36 and the shaft 50 of the crankset through the wall of the cover 32, the dynamic seals 123 and 124 the sealing of the space 30a vis-à-vis the outside, of the continuously variable ratio device 60 between the hub 86 and the casing 21 and with the arm 54 of the crankset.

[0111] A quasi-static seal 125 between the fork shaft 44 and the housing 21 is visible in [Fig.4].

Claims

1. Demands Electric and muscle-powered bicycle drive unit (10), arranged at the bottom bracket, comprising: • an electric motor(20); • a reducer (30), consisting of a driving gear (24a) machined at one end of a rotor shaft (24) of the motor (20), a driven pinion (34) guided by a smooth ring (35) on a hollow shaft (36), and guided by a needle bearing (37) on a shaft (50) of a pedal assembly. This reduction stage is contained in an enclosed space (30a) formed by a motor housing (21), a housing (31) and a sealed reducer cover (32) containing a lubricant; • a fixed hub (41) secured to the hollow shaft (36) by splines (36a) and a sliding sleeve (42) whose internal splines cooperate with splines (41a1) on the outer periphery of the hub (41) and with splines (34a1) on the outer diameter of the bearing (34a) extending laterally beyond the teeth of the driven pinion (34). The sliding sleeve (42) also has axial teeth (42a) on one of its lateral faces. The sliding sleeve has three positions: • the first, when it is carried only by the splines(34al) of the driven pinion(34) of the reducer(30), corresponding to the disengagement of the motor(20) and the wheel, also called the disengagement position; • the second, when it is carried both by the splines(34al) of the driven pinion(34) of the reducer(30) and those(41al) of the fixed hub(41), corresponds to the joining of the motor and the wheel, also called the dog clutch position; • The third, when it is supported both by the splines (34al) of the driven pinion (34) of the reducer (30) and those (41al) of the fixed hub (41), and when its axial teeth (39a) are engaged in notches (31a) belonging to the reducer housing (31), corresponds to the locking of the electric motor (20) and the rear wheel (not shown) and acts as an anti-theft device; a control device for the sliding sleeve(42) comprising a fork(43) carried by a shaft (44) passing through the motor housing(21), a shaft control arm(45) with a threaded bore (45a), a stepper motor(46) for actuation with a threaded shaft(46a) cooperating with the threaded bore(45a) of the control arm(45); a second reduction stage outside the closed space(30a) of the first reduction stage comprising a driving gear(39) integral with the hollow shaft(36), a driven gear integral with the rear wheel without a free wheel and linked to the driving gear by a roller chain or a toothed belt (not shown); a crankset comprising a shaft (50), with at each end grooves (50b,50c) for driving the two arms (53,54) at the end of which are arranged the pedals (not shown); a continuously variable ratio device(60), comprising a driving pulley composed of two flanges(64,65) carried and driven by the bottom bracket shaft(50), a driven pulley composed of two flanges(70,71) carried by an intermediate shaft(61) and a belt(63). The power and movement of the driven pulley are referred to the toothed chainring(56) by driving sprockets (80), intermediate sprocket(81) and driven sprocket(85) ensuring the rotation in the same direction of the bottom bracket and the rear wheel; a first speed sensor(l 12) arranged on the cover(32), with notches(l 13a) cut into a target(l 13) carried by the hollow shaft(36) in permanent connection with the rear wheel (not shown) and providing the computer with the speed information of the bicycle; a second speed sensor(l 10) arranged on the engine casing(21), has as its reading track the notches(l 1 la) of the target(l 1 l) brought onto the flange(65) of the drive pulley and provides the computer with the pedaling speed information; • a control computer (not shown).

2. Electric and muscle-powered bicycle drive unit(10) according to claim 1 characterized in that the flanges(64,65) of the drive pulley are rotationally fixed by splines(64a-65a), the flange(64) carrying the flange(65) is rotationally fixed to the crankshaft(50) by the splines(50c) and the assembly is axially free with respect to the shaft(50).

3. Electric and muscle-powered motor-propulsion group(10) for bicycle according to claim 1 characterized in that flanges(70,71) of the driven pulley are rotationally fixed by splines (70a-71a), the flange(70), carrying the flange(71) is free to rotate on the intermediate shaft(61) because it is carried by a needle bearing(72).

4. Electric and muscle-powered powertrain (10) for bicycle according to claim 1 or 2 characterized in that a spring (66) pushes the flanges (64,65) towards each other and puts a belt (63) under pressure, because it bears on one side on the flange (65) and on the other side on a washer (67) stopped by a ring (68) carried by the carrier flange (64).

5. Electric and muscle-powered powertrain (10) for bicycle according to claim 1 or 3 characterized in that the flange (70) bears against the casing (31) by means of a ball bearing (73).

6. Electric and muscle-powered powertrain(10) for bicycle according to claim 1 or 3 characterized in that a (hydraulic) cylinder(77) pushes the flange(71) via a ball stop(74) towards the flange(70) and defines the radius of action and thus the ratio (of reduction or multiplication) of the device(60).

Images