FR2991283A1 - ENERGY STORAGE AND RETURN SYSTEM FOR CYCLE AND CYCLE EQUIPPED WITH SUCH A SYSTEM - Google Patents

Abstract

System for storing and restoring energy, characterized in that it comprises: - a shaft (6); a wheel rim (3) or an element kinematically connected to the rim; - A torque transmission chain from a motor element (pedal / electric motor) to said rim (3) so as to put the rim or element kinematically connected thereto in rotation relative to said shaft (6); an epicyclic gear train comprising a first, a second and a third input / output part; a selective coupling mechanism (5, 7) of said second input / output part; and wherein, the first input / output part is constituted by said rim (3) or by said element kinematically connected to the rim, and the third input / output part is an inertia flywheel (1) movable in rotation relative to the shaft (6) capable of storing a kinetic energy and then transmitting it to the rim (3) or to said element which is kinematically connected thereto. The epicyclic gear train has: - an energy storage configuration, in which the second input / output part is locked with respect to the shaft (6); and an energy restitution configuration in which the second input / output part is locked with respect to the torque transmission chain.

Description

The present invention relates to a storage and energy recovery system for a cycle, as well as to a cycle equipped with such a system. BACKGROUND OF THE INVENTION Such a system is useful in particular when the rider needs a power that it is difficult to deliver only by conventional pedaling, for example to revive or climb a hill more easily. Some known cycles incorporate an energy storage system that assists the cyclist when needed. For example, some cycles are equipped with an electric battery powering an electric motor that helps the cyclist pedaling. In some cases, the battery is recharged by the pedaling movement of the cyclist. Electric batteries are expensive and wear out gradually during charging and discharging cycles. In addition, this system generates losses during the storage of electrical energy in the battery, as well as losses related to the internal resistance of the battery, during the return of the electrical energy. The conversion of electrical energy into mechanical energy generates yield losses. In addition, the efficiency of the electric motor degrades the performance of this system. Hybrid vehicles usually include an electric battery, an electric motor, and a complex system for managing the battery and the engine. This system has a large number of parts, which is not suitable for cycles that have a reduced size and whose mass must not be too large. Some vehicles are equipped with a flywheel to store and return kinetic energy and return it in time. However, it is necessary to associate the flywheel with a complex speed variator because the transmission ratio between the transmission of the vehicle and the flywheel must vary in very high ratios with extremely high transient powers. Such a variable speed drive is not suitable for a cycle because of its size and mass. It is to these drawbacks that the invention more particularly intends to propose by proposing a storage and energy recovery system for a cycle having a bulk and a low mass, of simple and inexpensive design, having a good efficiency and a low wear over time. For this purpose, the subject of the invention is a system for storing and restoring energy, characterized in that it comprises: a shaft a wheel rim or a member kinematically connected to the rim, a transmission chain of torque from a motor element (pedal / electric motor) to said rim so as to put the rim or element kinematically related thereto in rotation relative to said shaft; an epicyclic gear train comprising a first, a second and a third input / output part and a mechanism for selective coupling of said second input / output part; wherein, the first input / output part is constituted by said rim or said element kinematically connected to the rim, and the third input / output part is a flywheel movable in rotation relative to the shaft capable of storing a kinetic energy and then transmitting it to the rim or element that is kinematically linked to it. Thanks to the invention, when the cyclist wishes, he can alternately store energy and then have it restored. To do this, it will be sufficient to operate the selective coupling mechanism. Since the flywheel is directly connected to one of the input / output parts of the epicyclic train and the rim of the wheel, itself, is connected to another input / output part of the train, it is has a system where the flywheel can directly restore energy to the rim, without other intermediary. This system has a relatively low weight in comparison with other energy recovery systems, which makes it particularly suitable for cycles, including the cycles driven by human strength .. This system also has a low cost because it incorporates little the rooms. The steering wheel can be made of inexpensive material such as steel. The energy density of this system is high, that is to say it is capable of storing a large amount of energy relative to its mass. Unlike systems that include an electric battery, this system has no wear associated with charging and discharging cycles.

According to advantageous but non-obligatory aspects of the invention, such a system for storing and restoring energy may incorporate one or more of the following characteristics, taken in any technically permissible combination: The epicyclic gear train admits: a storage configuration of energy, in which the second input / output piece is locked with respect to the shaft; and an energy restitution configuration in which the second input / output part is locked with respect to the torque transmission chain. System according to one of the preceding claims, characterized in that the epicyclic gear comprises a ring gear internally secured to the rim, a carrier and a sun gear integral with the flywheel. - The coupling mechanism comprises a movable clutch which, in the energy storage configuration, immobilizes the satellite door and, in the configuration of restitution of stored energy, connects the carrier to the satellite transmission chain. The epicyclic train has a neutral configuration, in which the pedaling of the cyclist does not involve storing kinetic energy in the flywheel and in which the cyclist does not recover kinetic energy stored by the flywheel. The coupling mechanism comprises a clutch which, in the neutral configuration, releases the rotation of the satellite door (blocks the rotation) of the flywheel. A freewheel mechanism connecting the flywheel to the hub of the wheel and automatically blocking the rotation of the flywheel when its kinetic energy is fully restored. The invention also relates to a driving wheel for a cycle, equipped with a storage system and kinetic energy recovery as described above and a cycle equipped with such a wheel.

The invention will be better understood and other advantageous aspects thereof will appear more clearly in the light of the following description of a cycle equipped with a storage system and energy recovery according to the invention, given only by way of example and with reference to the accompanying drawings in which: - Figure 1 is an exploded perspective view of a cycle wheel including a storage system and energy recovery according to the invention; FIG. 2 is a cutaway perspective view of the wheel of FIG. 1; - Figure 3 is a cross section of the wheel; FIG. 4 is an enlarged view of detail IV in FIG. 3; FIGS. 5, 6 and 7 are partial perspective views of the wheel, respectively in an energy storage configuration, in an energy recovery configuration and in a neutral configuration; FIGS. 8, 9 and 10 are simplified diagrams of the wheel, respectively in the energy storage configuration, in the configuration of restitution of the stored energy and in a neutral configuration; and FIGS. 11, 12 and 13 are simplified diagrams of the wheel, respectively in the energy storage configuration, in the configuration of restitution of the stored energy and in a neutral configuration. FIG. 14 is a simulation graph, representing the speed as a function of the distance traveled for a record-ironed flatbed bicycle, with a standard transmission (dashed curve), and with a kinetic wheel according to the invention in strong line. FIG. 15 represents the simulation of the rotational speeds with respect to the bicycle, the various elements composing the invention, speed of the kinetic flywheel in radians per second, speed of the satellite door in radians per second, speed of the rim of the wheel. driving the bike in radian per second and the pedaling speed of the cyclist expressed in revolutions per minute, and their respective evolution as a function of time expressed in seconds. FIG. 16 represents a balance of the powers as a function of time expressed in seconds, on the record simulation of FIG. 14 with the kinetic wheel according to the invention. FIG. 17 shows a bicycle equipped with a system for storing and recovering energy according to a first embodiment of the invention. - Figure 18 shows a bicycle equipped with a storage system and energy recovery according to a second embodiment of the invention. - Figure 19 shows a bicycle equipped with a storage system and energy recovery according to another embodiment of the invention. Figures 1 to 3 show a rear wheel 100 of a cycle, rotatable about a hollow hub or shaft 6 extending along an axis of rotation X of the wheel 100. The ends 62 and 63 of the shaft 6 are threaded and each cooperate with two nuts 76a or 76b provided to secure the shaft 6 to the frame of the cycle, not shown.

The wheel 100 comprises a rim 3 and a tire, not shown, mounted on the rim 3. The rim 3 comprises a body 31 receiving the tire, and a cover 32 assembled to the rim body 31 by means of screws A When they are assembled, the rim body 31 and the cover 32 delimit a volume having generally the geometry of a disc. The rim body 31 comprises a hub 35 centered on the X axis, mounted free to rotate relative to the shaft 6, about the X axis, by means of bearing bearings 93 and 94 of the type bearing. balls. The cover 32 is also rotatably mounted relative to the shaft 6, about the axis X, via a bearing bearing 98 of the ball bearing type. As can be seen in FIG. 17, when the cyclist is pedaling, the pedalboard drives a primary chain 102 through its plate 101, which drives a series of ten gears 103 whose number of teeth varies between 44 and 11 (44,38,32 , 28,24,20,17,15,13,11) successively selected by a derailleur, these pinions are connected to an intermediate shaft 104 which drives a secondary plate, a secondary chain with fine pitch 105, which meshes with the latter secondary plate with a motor pinion 81 disposed between two flanges 82 guiding the chain, integral with a freewheel body 8 centering the rim body 31 by the support bearing 93, the freewheel body 8 being itself freely mounted rotation around the shaft 6 by means of bearing bearings 91 and 92 of the ball bearing type. The freewheel body 8 is hollow and is provided with an internal toothing 83. Three pawls 84 angularly separated from each other by 120 ° about the X axis are pushed radially by 3 small springs (not shown), thus the 3 pawls 84 interact with the internal toothing 83 of the freewheel body 8 in a unidirectional manner, for selectively securing the freewheel body 8 to the hub 35 when the freewheel body 8 is driving relative to the hub 35 because the cyclist exerts a driving force in rotation of the freewheel body 8, by means of the chain. The pawls 84 allow a unidirectional rotation of the hub 35 relative to the freewheel body 8 and do not oppose the rotation of the wheel 100 when the cyclone stops pedaling or more generally, when the wheel 3 rotates faster than free wheel body 8. A brake disc 34 is fixed to the cover 32 of the rim 3 by screws C. The cycle is equipped with a brake shoe not shown, receiving the brake disc 34.

An "epicyclic gear" type system is housed inside the volume delimited by the rim 2. This epicyclic gear train moves around the shaft 6, which is fixed relative to the frame of the cycle, and consists firstly of a outer ring 33 which has an internal toothing 38 and which is fixed to the rim body 31 by means of screws B. The epicyclic gear also comprises a planet carrier 2 comprising two arms 23a and 23b aligned with each other and fixed on either side of an annular body 21 mounted free to rotate on the shaft 6, about the axis X, via a bearing bearing 95 of the ball bearing type. Two satellites 4a and 4b each having an external toothing 41 are rotatably mounted about an axis X4a or X4b, relative to the ends of the arms 23a and 23b opposite the annular body 21, by means of support bearings 95a. and 95b. The external toothing 41 of each satellite 4a and 4b meshes with the internal toothing 38 of the outer ring gear 33. The epicyclic gear train also comprises a flywheel 1 mounted free to rotate with respect to the shaft 6, about the X axis, by The flywheel 1 comprises a central pinion 11 provided with an external toothing 13 which meshes with the external teeth 41 of the satellites 4a and 4b. The steering wheel 1 corresponds to the "sun gear" of a conventional epicyclic gear train. The steering wheel 1 has a peripheral solid portion 12 which gives the steering wheel 1 a mass of about 3.4 kg and a rotational inertia of about 70 g.m2. As explained in more detail below, the flywheel 1 or "flywheel" is used to store a portion of the cyclist's mechanical energy pedaling. In case of need of power, the cyclist can recover this stored kinetic energy, in particular to revive or climb a hill more easily. The ring 33, and therefore the rim 3 which is secured thereto, the steering wheel 1 and the satellite carrier 2 therefore constitute the three input / output parts of the epicyclic gear train. We will see later that alternatively depending on the operating configurations, these three pieces will be either inputs - they will then be driving - or outputs - they will then be conducted. The epicyclic gear train has three operating configurations: a storage configuration, represented in FIGS. 5 and 8, in which a part of the cyclist's mechanical pedaling energy is stored in the flywheel in the form of kinetic energy of rotation, this phase is shown in Figure 14 between the zero distance and the distance of 6000 meters. This phase is represented in FIGS. 15 and 16 between the initial time t = 0 s and t = 317 s - a restitution configuration, represented in FIGS. 6 and 9, in which the kinetic energy stored is restored in the form of a motor torque allowing the rotational drive of the wheel 100, this configuration is shown in Figure 14 for distances greater than 6000 m, this configuration is shown in Figures 15 and 16 for a time between 317 s and 569 s - a neutral configuration, represented in FIGS. 7 and 10, in which the cyclist does not store or recover energy, this configuration is not shown in FIGS. 14, 15 and 16, but necessarily exists in the transition phase at 6000m or 317s. As explained in more detail later, the change of configuration is achieved by the cyclist, by means of an actuating member 7 acting on a clutch 5 mounted on the shaft 6, between the freewheel body 8 and the pinion gear 11 of the flywheel 1. Depending on the given control command, the satellite door 2, which is rotatably connected with the claw 5, does not interact with the epicyclic gear or is blocked in rotation with the shaft 6 is integral in rotation with the drive pinion 81 The clutch 5 is in the form of a ring in which is formed an inner circumferential groove 54. The shaft 6 has an oblong hole 61 whose length is oriented parallel to the axis X. A pin 73 of square section is disposed in the oblong hole 61 of the shaft 6. The length of the oblong hole 61 is greater than the length of the sides of the pin 73. Thus, the pin 73 is movable in translation in the oblong hole 61. The s ends of the pin 73 are housed in the circular groove 54 of the clutch 5, and the clutch 5 can pivot freely about the axis X but the clutch is linked in translation to the pin 73.

The actuating member 7 comprises a rod 71 which is fixed to the pin 73 and extends inside the shaft 6. At the opposite of the pin 73, the rod 71 is extended by a chain 72 which protrudes outside the shaft 6, on the opposite side to the freewheel body 8. The chain 8 is connected to a control cable, not shown, actuated by the cyclist by means of a lever attached to the handlebar of the cycle. The clutch 5 can thus move in translation between the freewheel body 8 and the toothed gear 11 of the flywheel 1. A return spring 74 is housed in the shaft 6, around the stem 71 of the clutch member. coupling 7, and pushes the pin 73 by default to the freewheel body 8.

As can be seen in FIGS. 5 and 6, each axial end 51 and 52 of the clutch 5 has notches which form slots 55. The slots 55 of the first axial end 51, which is situated on the side of the freewheel body 8, are adapted to engage a crenellated ring 85 fixed at the level of the freewheel body 8, so as to rotate the dog clutch 5 with the drive pinion 81 about the X axis.

The crenellations 55 of the second axial end 52 of the clutch 5, which is located on the side of the flywheel 1, are adapted to engage with a crenellated ring 64 attached to the shaft 6, so as to firmly rotate the clutch 5 to The outer peripheral surface of the dog 5 has longitudinal grooves forming splines 53. In a complementary manner, the annular body 21 of the planet carrier 2 has internal splines 22 which are adapted to cooperate with the grooves 53 of the clutch 5, so as to join in rotation, about the X axis, the clutch 5 with the planet carrier 2. Thus, the clutch 5 is connected in rotation to the satellite door 2 around the X axis, and linked in translation to the control pin 73 along the axis X. Thus, depending on the configuration activated by the cyclist, the satellite door 2 which is connected in rotation with the clutch 5 can either link in rotation with the tree 6 in bl oquant rotation, or to bind in rotation with the drive pinion 81, or remain completely free in rotation in the neutral position. In known manner by applying, for example, the so-called Willis formula, the kinematics of the epicyclic gear train is governed by the following relation (1): 0) 3/0 = -Z1 / Z3. 0J1 / o + (1 + Z1 / Z3). with: 01/0: speed of rotation of the flywheel 1 with respect to the shaft 6 and thus to the frame of the cycle, 0) 2/0: speed of rotation of the planet carrier 2 with respect to the shaft 6 and therefore at the frame of the cycle E02 / 0, 0) 3/0: speed of rotation of the rim 3 with respect to the shaft 6 and thus to the frame of the cycle Z1: number of teeth of the toothed gear 11 of the flywheel 1, Z3: number of teeth of the outer ring 33 of the rim 3.

In the example shown in the figures, Z1 = 24 teeth and Z3 = 288 teeth. The Z1 / Z3 ratio is therefore equal to 12. The epicyclic train has three mechanical input and output parts: the ring 33, sometimes called outer planet, the planet carrier 2 and the sun gear 11 sometimes called inner planet. These three parts 1, 2, 3 have different speeds of rotation which are given by a single mathematical relation, namely the relation (1). Thus, it is necessary to set the rotational speed of two parts, to know the speed of rotation of the third part. In other words, the epicyclic gear train has two inputs and an output or an input and 2 outputs. In the example shown in FIG. 8, the rim 3 constitutes the entry because it is this driving part that will transmit a driving torque to the epicyclic gear train by the ring gear 33, the planet carrier 2 is locked to the shaft 6 while the steering wheel 1 will be an output because it will be driven by the epicyclic train receiving power. In the example shown in FIG. 9, the steering wheel 1 will this time be an input since its deceleration will provide a driving torque to the epicyclic gear train, the satellite carrier will be at its engine, since the motor gear of the cyclist will also provide a driving torque to the engine. epicyclic train while wheel 3 will be a receiver receiving a couple from the wheel and the cyclist who will provide a power to the wheel. The kinetic energy storage configuration is shown in FIGS. 5 and 8. To activate this configuration, the cyclist, by means of the control lever, pulls on the chain 72 so as to translate the clutch 5 towards the linked castellated ring 65. to the shaft 6 by moving the dog 5 away from the freewheel body 8, against the force exerted by the return spring 74. By this axial movement, the crenellations 55 of the end 52 of the clutch 5 come in engagement with the crenellated ring 64 fixed to the shaft 6, the satellite door is thus rotatably connected to the shaft 6, about the axis X. Now, the shaft 6 is fixed relative to the frame of the cycle , which has the effect of immobilizing the rotation of the planet carrier 2 relative to the frame of the cycle. The operation of the chain 72 to reach the storage configuration must be performed when the wheel 100 does not rotate, in particular when the planet carrier 2 is stationary, to allow coupling of the clutch 5.

Subsequently, when the cyclist begins to pedal, he drives the drive pinion 81 of the freewheel body 8 and the pawls 84 implanted in the hub 35 of the rim 3, lock in the toothing 83 of the freewheel body 8 so as to drive the rim 3 in rotation. The satellites 4a and 4b are rotated about their axes X4a and X4b by meshing with the outer ring 33 which is fixed to the rim 3. The satellites 4a and 4b then drive the steering wheel 1 in rotation, by meshing with the pinion gear 11, while the carrier remains stationary relative to the shaft 6. In this energy storage configuration, (02/0 = 0 since the planet carrier 2 is stationary relative to the shaft 6 The relation (1) thus gives: 0) 3/0 = -Z1 / Z3. (01/0 = -12 .C01 / 0 The flywheel 1 will therefore turn in a direction opposite to that of the rim 3, and at a speed 12 times greater.If the cycle comprises several transmission ratios, it is preferable to use a small transmission ratio to initiate the rotation of the steering wheel 1 which requires a relatively large torque given its mass.As the cyclist is gaining speed, it is desirable that he changes gear transmission to adapt its pedaling rate to a frequency allowing it to transmit to the steering wheel 1 a maximum of energy.In known manner, one can calculate the apparent mass ma = 177 kg of the steering wheel 1, that is to say say the mass of a virtual object which has a translational inertia equal to the rotational inertia of the steering wheel 1. The steering wheel 1 which rotates 12 times faster than the rim 3 and weighs 3.4 kg, stores the same energy a mass of 177 kg in translation at the same speed as the cycle, t almost twice as much as the total mass of the cycle and the cyclist. The total kinetic energy in this first phase of operation is thus almost 3 times greater than the kinetic energy of the cycle alone. Figure 14 shows the simulation of speed increase versus distance traveled, for a record-lined bike with a very low aerodynamic drag, with a cyclist providing a supposed constant power of 425 Watt over the entire duration of the record, the road being considered perfectly flat.

The first simulation in dashed line, simulates the rise in speed of a record cycle of the prior art, we can see that after 6000 meters traveled the bike is already rolling at the speed of 111 Km / h and that after 8000 meters or 2000 meters later it will have gained only 4 km / h additional, ie after 75% of the distance traveled the speed reached is already greater than 96% of the final speed, this rise in Asymptotic speed is due to the fact that the aerodynamic drag increases very rapidly with the square of the speed while the driving force developed by the cyclist decreases inversely with the speed when the power is constant, so the cyclist can no longer increase his speed. because the aerodynamic drag and the friction of bearings converge very quickly towards the driving force of the cyclist. The second simulation, in strong lines, begins with a storage phase up to the distance of 6000 meters, then switches to the restitution phase from 6000 meters to reach a very high speed in the timing zone of the last 200 meters between 7800 and 8000 meters. From the start the acceleration is lower than for the simulation of the prior art, because the apparent mass of the kinetic flywheel of 177 kg, is added to the total mass and thus decreases the initial acceleration of the cycle, on the other hand as the speed is lower there is much less loss associated with the aerodynamic drag, so after 6000 meters traveled the cyclist only rolls 97 km / h instead of 111 km / h and it will take 317 seconds instead of 254 seconds for the cycle of the prior art. As in this simulation the power is constant, the energy or the mechanical work is proportional to the duration, so in the first 6000 meters the cyclist will have provided a mechanical work of 135 KiloJoule whereas in the version of the prior art it will not will have provided that 108 KJ, more at the end of this storage area the kinetic steering wheel will have stored 64.1 KJ is almost half (47.5%) of the total work provided by the cyclist since departure. By observing FIG. 15 in the storage phase, ie within the first 317 seconds, it can be seen that the kinetic flywheel 1 has a high and negative rotation speed and will reach -1354 rad / s (= -12900 rpm), while that the speed of the wheel 3 will follow the linear speed of the cycle, the speed of the pedal will remain close to the optimum pedaling cadence of the cyclist between (100 and 120 rpm) thanks to the 10 shifts that the cyclist has made, it will have indeed started on a driven pinion of 44 teeth to finish on a small pinion of 11 teeth, these different changes can be observed by noting that the pedaling frequency of Figure 15 at a pace of sawtooth, each point of Tooth corresponds to a gear change made by the cyclist so that his pace always remains optimal in order to develop his power potential at best. It can also be observed in this figure 15 that the speed of the satellite gate 2 is zero over the entire storage phase since it remains blocked at the axis 6. The configuration of restitution of the stored energy is shown in Figures 6 and 9 and must be enabled when the storage configuration is active. To activate the restitution configuration, the cyclist acts on the control lever to release the tension of the chain 72. The return spring 74 pushes the control pin 73 and thus the dog 5 towards the freewheel body 8, the notches 55 of the end 52 of the dog 5 then disengage from the crenellated ring 64 of the shaft 6 thus releasing in rotation about the axis X, the clutch 5 which was locked to the shaft 6, the clutch is thus first released from any rotational coupling in an intermediate phase of neutral, releasing at the same time the satellite gate 2 in rotation which is a state according to Figures 7 and 9. This intermediate dead center position will be developed more far. By continuing the release of the control lever, the return spring will continue to move the control pin 73 and therefore the dog 5 to the freewheel body 8, the notches 55 of the end 51 will engage in the crenelated ring 85 integral with the freewheel body 8, which secures the dog 5 in rotation, about the axis X, with the input gear 81. Thus, the planet carrier 2 and the input pinion 81 rotate as a block around the shaft 6. A screw 65 is mounted in the shaft 6 and forms a stop of the pin 73 in the restitution configuration. The screw 65 makes it possible to adjust the end position of the pin 73 so that the force of the return spring 74 is not taken up by the rotating groove of the dog, which will dissipate energy and cause the premature wear of the control pin 73 and dog clutch 5. In the restitution configuration, the free wheel between the driving pinion 81 and the rim 3 is disconnected, so that the driving torque exerted at the drive pinion 81 by the cyclist causes rotation the dog 5 by the connection between the notches 55 of the end 51 of the clutch 5 which cooperate with the castellated ring 85 integral with the freewheel body 8. The satellite door 2, which was locked at rest, will thus be put in rotation about the axis X, which will have the effect of accelerating the rotation of the ring 33 while requesting a torque to the central flywheel via the sun gear 11, this torque demand will then start slowing down the steering wheel of inertia 1 which will thus restore its kinetic energy. In the restitution configuration, relation (1) gives, with the previous examples, the following speed relation: CO3 / 0 = -1/12. (01/0 + 13 / 12.002 / 0 Moreover, the analysis of the equilibrium of the forces in isolating the epicyclic gear (33,11,2) leads to the following relation of torque: C wheel / 33 + C pinion / 2 + C flywheel / 11 = 0 Considering only the absolute values we find C wheel = Z3 / (Z3-Z1) .0 input = 1,09.0 input C flywheel - Z1 / (Z3-Z1) .0 input = 0 , 09.0 input C input represents the motor torque provided by the cyclist via the drive pinion 81 C wheel represents the engine torque supplied by the outer ring 33 to the wheel 3 and which also represents the engine torque which is converted into a tangent force motor at the contact of the tire on the ground (not shown) C flywheel represents the torque transferred by the flywheel 1 to the sun gear 11 to which it is linked The steering torque C is generated by the deceleration of the steering wheel, it is determined by the relation: C flywheel-J-do1 / o / dt J represents the rotational inertia of the flywheel of about 70 g.m2 in In the example described, dw1i0 / dt represents the derivative of the speed with respect to time, ie the deceleration of the flywheel expressed in rad.s 2, this deceleration dw1 / o / dt is represented in FIG. 15 by the slope of the curve w1 / o = f (t), one can thus notice that at the beginning of the phase of restitution this slope is very high because the cyclist will be able to generate a couple of input very important since it will be on the smallest development with a reduced input speed, off as we saw above the flying C = 0.09 Centered.

These last two relationships show that the torque output to the wheel is well proportional to the input torque given by the cyclist's pedaling, just as the torque requested at the steering wheel is also proportional to the cyclist's effort. interesting facts show that it is the cyclist himself who automatically controls the discharge of the steering wheel, if he starts to freewheel, the engine torque becomes zero and the torque requested driving too, if he doubles his effort, all the couples are then doubled. At the beginning of the restitution phase, as the satellite door 2 was initially blocked, and that the motor pinion is now connected to it, the cyclist will start this restitution phase with a zero pedaling rate, as if he started from the complete stop , it will therefore be able to choose a gear ratio very geared using the largest pinion driven transmission of 44 teeth, allowing it to generate a very large torque at the input pinion 81. Or according to the relationship above C wheel = Z3 / (Z3-Z1) .0 input = 1.09.0 input, if the input torque is high, the torque transmitted to the wheel will be high also so that the acceleration of the cycle is going to be almost equivalent to that of a stopped start a little as if the cyclist changed the frame of reference by leaning on the steering wheel. When the cyclist transmits a torque to the planet carrier 2 by the driving pinion 81, he will then automatically request torque from the flywheel 1. When the cyclise pedal, it automatically recovers the energy of the flywheel 1. The rotational speed wiio of the steering wheel 1 will therefore decrease and the steering wheel 1 will thus yield its kinetic energy to the system. The total power transmitted to the wheel 100 is then the sum of the power provided by the cyclist's pedaling and the power supplied by the deceleration of the steering wheel. In other words, the pedaling effort of the cyclist is then assisted by the energy restored by the steering wheel 1. As the steering wheel slows down and the satellite door accelerates the cyclist will have to change very quickly all ten reports of its transmission from the 44 teeth to the 11 teeth, these multiple changes of transmission ratios are visible on the curve N pedaling = f (t) of figure 15 by its new sawtooth pitch from the time 317 seconds , each tooth tip corresponding to a change of pinion to better adapt its pace of pedaling to the optimum (between 100 and 120 rpm) to exploit its power potential. In our example of speed record, the speed will go through a maximum before the steering wheel has given up all its energy, indeed the only power of the cyclist is not sufficient to maintain the maximum speed, it is therefore necessary to trigger the energy release at the right moment to optimize the maximum speed measured for the example between 7800 and 8000 meters, so in the simulation described in figure 14 the cyclist will suddenly be able to go from 97 Km / h to 136 Km / h in just 57 seconds while continuing to develop the same power of 425 Watts.

This unexpected energy effect can easily be explained by analyzing FIG. 16 which represents the powers developed as a function of time by the cyclist, the kinetic flywheel (1) and the driving wheel (3). For the duration of the record, the rider's power was considered constant and equal to 425 Watts (except at the start, where it quickly grew since zero because the initial speed is zero), this is what we find on the cyclist P = Cte = 425 Watts (horizontal line). In the first phase of storage (between t = 0 and 317 s) we can notice that the power supplied by the steering wheel (broken line) is negative, so it takes the power and therefore the energy supplied by the cyclist, this storage power decreases in absolute value because the acceleration of the cycle and therefore the steering wheel will decrease as the aerodynamic friction will increase.

The power provided by the driving wheel (dotted on the curve) is always the sum of the power of the cyclist summed by the power supplied by the steering wheel (neglecting the internal mechanical friction), in this first phase the power supplied by the steering wheel being negative, the power supplied to the wheel is the power provided by the cyclist less the power taken by the steering wheel. It can be noted that the energy supplied by the cyclist can be represented by the area under the curve W = f P.dt From the beginning of the restitution phase, the power developed by the steering wheel becomes positive is very high more 7000 Watts on the first seconds to decrease as and when following the following differential law: P flying = -J. 0) 110.d o 110 / dt The steering wheel will therefore add a very high transient power that will help the cyclist to accelerate suddenly. It may be noted that in our example described in Figure 16, the friction being neglected, the work of the steering wheel is conservative so that the area between the curve and the abscissa axis in the storage period is equivalent to the area in the restitution phase. In our example of speed record, we saw that the maximum speed was reached before the steering wheel gave up all its energy, if the cyclist continues his effort, the deceleration of the steering wheel will continue until the steering wheel has failed. all its energy, the ideal being to stop the steering wheel when it reaches zero speed (t = 570 s on the graph of Figure 15), this function is mechanically easy to integrate by adding a unidirectional freewheel system ( not shown) between the wheel 1 and the shaft 6, so that when the wheel slows down to reach zero speed, the freewheel immobilizes it so that it does not restart in the other direction under the effect of the torque wheel. In this embodiment comprising a free wheel between the flywheel 1 and the shaft 6, the end of the restitution ends when: E0vo = 0 By replacing in the speed equation we find 0) 3/0 = (1+ Z1 / Z3) .0) 2/0 = 1,083.0) 2/0 = 1,083.0) pinion Thus the wheel rotates slightly faster than if it were driven directly by the free wheel as in the initial phase of energy storage. From this moment, the cyclist can then: Either continue to pedal normally leaving the control lever in the playback mode.

Either put the control lever in the neutral position, which will have the effect of snapping the three pawls 84 of the freewheel so that the wheel 3 is driven directly by the input pinion 81 then CO3 / 0 = CO pinion Either put the control lever in storage position, which will increase the apparent weight of the cyclist and start a new energy loading cycle. The embodiment shown in the figures does not include this additional freewheel, thus at the end of the energy restitution phase, the flywheel which initially rotated in the opposite direction of the wheel 3, will decelerate until reaching zero speed, it will then start in the opposite direction is in the same direction as the wheel by storing a little energy, but the 3 pawls 84 of the freewheel will quickly block its acceleration to bind in rotation with the wheel 3 because the wheel free imposes the speed inequality: CO 1/0 C CO 3/0 By replacing in the equation linking the velocities, the only final solution then becomes: CO 1/0 - w 3/0 = CO 2/0 In other words by the automatic locking of the freewheel, all the elements of the planetary gear train will start to spin in the end in the same direction and at the same speed. Although this embodiment is theoretically less optimum than that comprising a free wheel between the wheel 1 and the shaft 6, it has the advantage of simplifying the mechanism using the same freewheel for 2 different functions. This mode of operation is the one described in Figure 15, we see that the rotation speed of the wheelw 1/0 which was negative will go through zero (t = 570 s) then become positive to become equal to the speed of the wheel 3 (t = 616 s) and the speed of the input pinion 81. The neutral configuration is shown in FIGS. 7 and 10. When the cyclist wishes to activate the neutral configuration, he actuates the control member 7 which moves the clutch 5 to an intermediate position in which it is not coupled with the crenellated ring 85 of the freewheel 8, nor with the crenellated ring 65 of the shaft 6.

The stability of this position is improved by means of springs 25 arranged in holes in the annular body 21 of the planet carrier 2. These springs 25 push balls 24 into recesses formed in the outer surface of the clutch 5. In the neutral position, the free wheel between the motor pinion 81 and the rim 3 is again connected and the cycling of the rider causes the rotation of the rim but does not cause the rotation of the steering wheel 1 which tends to retain its movement. If the steering wheel 1 rotates when the neutral configuration is activated, then it retains its rotational movement, and decelerates very slightly because of the friction. If the steering wheel 1 is stationary when the neutral configuration is activated, it tends to remain motionless by inertia. The pedaling force therefore only causes the rotation of the rim 3.

The neutral configuration allows the rider not to feel the effects of the flywheel by not slowing the cyclist in its acceleration and allowing to conserve the kinetic energy stored in the steering wheel while slowing down to a complete stop. It is also a security. The operating mode described above is particularly suitable for achieving speed records or for providing a very high transient power. The following description relates to a second mode of operation for recovering the energy dissipated by braking. In this second embodiment, the system 106 for storing and restoring the energy may for example be used for a city bike and in particular for a bicycle that benefits from electric assistance. In the second embodiment, as shown in FIG. 18, there is no intermediate shaft. The single drive gear 81 of the first mode is replaced by a cassette of a plurality of rear gears 103 whose number depends on the number of gear ratios (speeds) of the transmission chain of the bike. The second mode of operation also admits three operating configurations: a neutral configuration, shown schematically in FIG. 11, an energy storage configuration, represented diagrammatically in FIG. 11, a configuration of restitution of the stored energy, represented in figure 12.

In the neutral configuration of the second mode of operation, the flywheel is not driven. Because of its inertia, and although it is free in rotation, it does not rotate with respect to the shaft 6. The relation (1) thus gives: CO3 / 0 - (1 + Z1 / Z3). In the neutral configuration (Fig. 11), the flywheel 1 does not rotate and the planet carrier 2 rotates in the same direction as the rim 3 at a slightly lower speed. pedaling provided by the cyclist is used only for the rotation of the wheel 100, without energy storage.The cyclist activates the storage configuration (FIG 12) when it is launched, for example at 30 km / h, and wishes In the storage configuration, braking means 9, in particular a clutch or a brake, gradually slow down the speed of rotation c) 2, o of the planet carrier 2. The braking of the planet carrier 2 will then cause the rotation flywheel 1 which will store the kinetic energy. It may be noted that these braking means are retarders and in principle do not allow to decelerate until the complete stop, they must be mounted in addition to a main braking system ensuring the safety of the cyclist in all circumstances, these The storage-activated braking means 9 can be easily integrated into the cycle by a back pedaling system which can be controlled at any time and independently of the conventional brakes of the cycle. The cyclist activates the energy feedback configuration (Fig.13) when he wants to restart, while the storage configuration is active. In this configuration, the planet carrier 2 is again free to rotate. The clutch 5 connects the drive pinion 81 to the planet carrier 2. When the cyclist starts to pedal, the planet carrier 2 is stopped and the flywheel 1 then releases its energy by a power supply helping the cyclist to restart the cycle.

The help will end when the steering wheel 1 has completely decelerated. The cyclist can then reactivate the neutral position so as not to penalize the acceleration of the cycle. According to the invention, the flywheel 1 forms one of the two inputs of the planetary gear train, that is to say that its rotational speed conditions the rotational speed of the output of the epicyclic gear train, formed by the rim 3.

The invention is not limited to the architecture of the epicyclic gear given as an example. For example, the satellites may be of the double-tooth type. The sun gear 11 may be in the form of a ring gear with internal teeth. The ring 33 may be in the form of a pinion with external teeth. The rim 3, that is to say the output of the epicyclic train receiving the engine torque, corresponds to the ring gear of the epicyclic gear but alternatively, it can be formed by the planet carrier or the sun gear of the planetary gear train. Similarly, the flywheel 1, that is to say a first input of the epicyclic gear conditioning the speed of the output, corresponds to the sun gear of the planetary gear train but alternatively, the wheel 1 can be formed by the crown outside of the epicyclic gear train or by the carrier.

In another embodiment, a freewheel can be incorporated between the flywheel 1 and the shaft 6 of the wheel 100 so that the flywheel 1 automatically comes to lock when its energy is completely restored. This embodiment, however, requires the use of an additional freewheel. In another mode of operation, it may be noted that if the cyclist is kept at a standstill and that he connects the control lever in the restitution position, if he starts to pedal in reverse, the satellite door will then turn in reverse while the speed of the wheel and therefore pinion 33 will be zero and the speed equations will follow the following relations: (03/0 = 0 X1 / 0 = (Z3 + Z1 / Z1) .0) 2/0 = 13-0) 2 / o (02/0 is negative since the cyclist pedal in reverse, the speed of the steering wheel will be negative and the steering wheel will store energy while the bike is stopped. To simply restore this energy, the cyclist will then have to put the control lever in neutral position, start his bike normally and order the restitution of the energy as soon as he reaches the speed of synchronism which will then allow him to put back the lever of control in restitution position so he can as in the description ecced from the mode of restitution to recover the kinetic energy accumulated at the stop. While the embodiments described and mentioned so far are all systems where the flywheel is placed inside the wheel, we can also consider solutions where the flywheel and the epicyclic train does not is not placed in the wheel. This is the case in the embodiment shown in Figure 19 where the system 106 for storing and restoring energy is placed at the level of the pedal. In this case, the first input / output part of the epicyclic gear train is secured to the front plate 101. The front plate is, in turn, in a conventional manner, kinematically linked with the rear drive wheel via a chain and a set of pinions. rear 103.

In the context of the invention, the various embodiments and variants may be combined with each other, at least partially.

Claims (8)

REVENDICATIONS1. System for storing and restoring energy, characterized in that it comprises: a shaft (6) a wheel rim (3) or a member kinematically connected to the rim, a torque transmission chain from a driving element up to said rim (3) so as to put the rim or element kinematically connected thereto in rotation with respect to said shaft (6); an epicyclic gear train having a first, a second and a third input / output part and a selective coupling mechanism (5, 7) of said second input / output part; wherein, the first input / output part is constituted by said rim (3) or by said element kinematically connected to the rim, and the third input / output part is a flywheel movable in rotation with respect to the shaft (6) capable of storing a kinetic energy and then transmitting it to the rim or element which is kinematically connected thereto. 2. System according to claim 1, characterized in that the epicyclic train comprises a ring gear (33) internally secured to the rim, a planet carrier (2) and a sun gear (11) integral with the flywheel. 3. System according to one of claims 1 or 2, characterized in that the epicyclic train admits: an energy storage configuration, wherein the second input / output part is locked relative to the shaft (6 ), an energy restitution configuration in which the second input / output part is locked with respect to the torque transmission chain. 4. System according to claim 3, characterized in that the coupling mechanism (5, 7) comprises a clutch (5) movable which, in the energy storage configuration, immobilizes the satellite door (2) and, in the restitution configuration of the stored energy connects the planet carrier (2) to the rim (3). 5. System according to one of the preceding claims, characterized in that the epicyclic train has a neutral configuration, in which the pedaling of the cyclist does not lead to storage of kinetic energy in the flywheel (1) and in which the cyclist does not recover kinetic energy stored by the flywheel (1). 6. System according to claim 5, characterized in that the coupling mechanism (5, 7) comprises a clutch (5) which, in the neutral configuration, blocks the rotation of the flywheel (1). 7. System according to one of the preceding claims, characterized in that it comprises a freewheel mechanism connecting the flywheel (1) to the hub (6) of the wheel (100) and automatically blocking the rotation of the wheel. flywheel (1) when its kinetic energy is fully restored. 8. Cycle wheel (100), characterized in that it is equipped with a kinetic energy storage and restitution system according to one of the preceding claims.