Transmission assembly for mobility equipment and process

Abstract

The invention relates to a transmission assembly (700) for a mobility device, said assembly comprising an electric motor (300) and a gear-changing device (100) having a plurality of k ratios between a first ratio (G1) and a higher ratio called ratio (Gk,) and a particular reduction ratio (Ri), between an input shaft (200p), arranged to be connected to a pedal assembly (940) of the mobility device, and an output shaft (230) of the gear-changing device when the ratio (Gi) is engaged, the gear-changing device further having a neutral ratio which, when engaged, does not allow a movement of the pedal assembly (940) to propel the mobility device, said assembly further comprising a control unit (800) arranged to control the gear-changing device (100) and the electric motor (300) in reverse mode and / or in regenerative braking mode. Figure to be published with the abbreviation: Figure 2

Description

Title of the invention: Transmission assembly for mobility device and method

[0001] The field of the present invention is that of so-called soft mobility, and more particularly that of mobility devices combining electric propulsion and muscular force, for example electrically assisted bicycles.

[0002] The invention relates in particular to electrically assisted city bikes as well as mountain bikes or touring bikes as well as cargo bikes.

[0003] Gearboxes for cycles are known from the prior art. In particular, publication FR2975367 A1 discloses a gear changing device for bicycles comprising a gear box and a sliding shuttle for selecting the ratio. The device and the gears of the gearbox are arranged in a common housing. While the field of light pedal-driven vehicles for transporting goods or people is diversifying, there is a need for automatic and electric gearboxes that are reliable and easy to manufacture.

[0004] Application DE102009029655 A1 describes a method for controlling the auxiliary electric drive of a bicycle. A control unit is provided for controlling the auxiliary electric drive in such a way that a uniform drive force is continuously generated from the power component applied by the driver and the power component applied by the electric auxiliary drive.

[0005] Application EP2480446 A1 discloses, for a bicycle having an auxiliary electric drive, a method for recovering and accumulating energy when the direction of rotation of the pedal assembly is directed backwards.

[0006] There is a need to further promote and improve the handling of electrically assisted bicycles as well as energy recovery in braking mode.

[0007] To meet at least in part these needs, the invention, according to a first aspect, relates to a transmission assembly for a mobility device,

[0008] said assembly comprising an electric motor and a speed change device having - a plurality of ratios between a first ratio and a higher ratio, and - a particular reduction ratio, between an input shaft and an output shaft of the gear change device when a particular ratio is engaged,

[0009] the gear change device further having a neutral ratio,

[0010] said assembly further comprising a control unit arranged to control the gearshift device and the electric motor in reverse mode and / or regenerative braking mode.

[0011] The input shaft of the transmission assembly is in particular arranged to be connected to a pedal assembly of the mobility device.

[0012] The output shaft of the transmission assembly is in particular arranged to be connected to at least one wheel of the mobility device.

[0013] When the neutral gear is engaged, it does not allow a movement of the pedals to propel the mobility device.

[0014] The mobility device is an electrically assisted mobility device. The electric motor provides in particular a portion of the propulsion power when the instantaneous speed of the mobility device is below a threshold value. In the context of the present application, the expression mobility device and device will be used interchangeably.

[0015] According to one embodiment, the machine comprises at least one wheel, it can comprise two, three or four wheels, or even more.

[0016] The machine can be used with or without electric assistance. In the context of the present invention the terms pilot, driver, cyclist are equivalent.

[0017] Advantageously, the transmission assembly according to the invention has, alone or in combination, one or other of the characteristics below: - the electric motor is connected to an output pinion corresponding to one of the ratios of the gear change device. - it comprises a reducer, the electric motor being connected in particular to the output pinion of the speed change device via the reducer, in particular via a plurality of pinions of the reducer. The plurality of pinions may comprise five pinions, in particular a first pinion coaxial with the electric motor, a second pinion, input pinion of the reducer, meshing with the first pinion,

[0018] a third pinion, output pinion of the reducer, integral in rotation with the second pinion, the third pinion meshing with a fourth pinion, a fifth pinion arranged to mesh with the output pinion of the speed change device, the fifth pinion being integral in rotation with the fourth pinion. - According to various implementation examples, the control unit is arranged to further control at least one of a lighting system, a location and / or navigation system, a human-machine interface system, this list not being exhaustive. - the transmission assembly is housed in a box, notably located at the level of the pedal assembly - the control unit is arranged to receive an instruction from a user of

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[0026] the mobility device. The instruction is notably a reverse instruction. It can be progressive in speed. In another example, the instruction is a regenerative braking instruction. - the gearshift device has between 2 and 12 gears, or even between 5 and 9 gears. - when the higher gear is engaged, the output speed of the gear change device is, in particular, 4.5 times higher than the input speed of the gear change device. - the jump / reduction ratio between two consecutive gears of the gear change device is between 10% and 50%, or even between 10% and 40%, in particular between 15% and 40%, especially between 20% and 40%. The gear change device includes in particular - a series of input pinions arranged to rotate freely around a selector shaft, - a series of output pinions, integral in rotation with a hollow shaft, said hollow shaft, said hollow shaft being in particular arranged to surround a pedal axle of the mobility device, - a gearshift actuator arranged to engage a selected gear. Each gear has a particular ratio between the output speed and the input speed of the gear changing device. The gear change actuator advantageously comprises electrical means for engaging a gear, in particular a geared motor. The control unit of the transmission assembly is, for example, arranged to control the geared motor of the gear change actuator. The gear change actuator also comprises mechanical means for engaging a gear, for example a shuttle movable in translation in the selection shaft 200 as described in application FR2975367 AL According to another of these aspects, the invention also relates to a mobility device comprising a transmission assembly as described above. The machine includes in particular a battery, or any other rechargeable means known to those skilled in the art to provide the energy necessary to power the electric motor, a lighting system, a pedal assembly, a location and / or navigation system as well as a human-machine interface system. According to yet another of its aspects, the invention relates to a regenerative braking method for a mobility device implemented using a transmission assembly, as described previously. The regenerative braking process includes in particular a braking step engine which may be preceded by a neutral gear engagement step. Engine braking means that the engine no longer drives the wheels in this step. It is the wheels that drive the engine and allow the battery or the rechargeable power supply system of the electric motor to be recharged.

[0027] Advantageously, the engine braking step is followed by a mechanical braking step during which a mechanical braking system is activated.

[0028] During the engine braking step, the speed of the engine is in the opposite direction to the torque.

[0029] According to yet another of its aspects, the invention relates to a reversing method for a mobility device implemented using a transmission assembly, as described previously.

[0030] The reversing method includes in particular a step of controlling the electric motor in the opposite direction, i.e. in a direction corresponding to a movement of the mobility device in reverse, in particular preceded by a step of engaging the neutral gear. Brief description of the figures

[0031] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below for information purposes in relation to drawings in which:

[0032] [Fig.l] is a view of a mobility device according to one aspect of the invention,

[0033] [Fig.2] illustrates the transmission assembly of the mobility device of [Fig.l],

[0034] [Fig.3a] illustrates in section the torque path for one embodiment of the invention,

[0035] [Fig.3b] illustrates a detail of the embodiment of [Fig.3a],

[0036] [Fig.4] illustrates a housing housing a transmission assembly according to the invention,

[0037] [Fig.5a] and [Fig.5b] illustrate a particular implementation of the invention, and

[0038] [Fig.6a] and [Fig.6b] illustrate another implementation of the invention.

[0039] [Fig.l] illustrates a mobility device 900 according to one aspect of the invention. The machine 900 is here an electrically assisted bicycle comprising an electric motor 400 with an axis of rotation Xm. Said electric motor is arranged to provide part of the propulsion of said machine.

[0040] When moving without electrical assistance, the driving force is provided by the cyclist, it is transmitted to the wheels 950 by means of two pedals rotating around a crank axle Xp which drives the rear wheel by a chain.

[0041] As shown in [Fig.l], the machine 900 comprises a control unit 800 as well as several sensors 80, located in particular at the level of the pedal assembly, on the frame of the bicycle or at the level of a wheel. The control unit 800 is in particular arranged to control the electric motor 400 and the gear changing device 100.

[0042] The machine 900 shown here also comprises an energy storage device in the form of a battery 910, a lighting system 920, a pedal assembly 940 with an Xp axis, a location and / or navigation system 980 and a human-machine interface system 990 comprising in particular a touch screen capable of displaying information for and / or taking into account the requests of said user. The human-machine interface system 990 is in particular connected to the location system 980 and serves as a navigation interface. The invention is not limited to a particular human-machine interface system, and may comprise any system known to those skilled in the art.

[0043] The wheels 950 are equipped with a braking system 960, including in particular disc brakes 965.

[0044] The machine 900 comprises a transmission assembly 700 illustrated [Fig.2]. The transmission assembly 700 comprises a speed change device 100 and an electric motor 400 with an axis of rotation Xm to provide part of the power for propelling the machine. As shown in Figures 1 and 2, the speed change device 100 is housed in a housing 600 illustrated in more detail [Fig.4]. The housing 600 is here positioned at the level of the pedal assembly 940, the axis of which coincides with the output axis X3 of the speed change device 100.

[0045] As shown in Figure 3, the gear changing device 100 as illustrated comprises - a series of input pinions 20 arranged to rotate freely around a selection shaft 200, - a series of output pinions 30, integral in rotation with a hollow shaft 230, said hollow shaft being arranged to surround a pedal axle 200p of the mobility device 900, - a gearshift actuator 150 arranged to engage a selected gear.

[0046] The gearshift actuator comprises mechanical means for engaging a gear, for example here a shuttle 155 movable in translation in the selection shaft 200 which is hollow and electrical means for engaging a gear, in particular a geared motor for moving the shuttle 155 between a position Po corresponding to the neutral gear and positions Pi to P7 corresponding to speed ratios n°1 to n°7.

[0047] Figure 3 illustrates in solid lines the torque path Cwu for the torque supplied by the user, in particular without electrical assistance. The torque input is via a shaft 200p of the crankset 940, the torque passes through a first primary multiplication pinion 11 which meshes with a second primary multiplication pinion 12. The first primary multiplication pinion 11 is rotationally fixed to the shaft 200p of the crankset and the second primary multiplication pinion 12 is rotationally fixed of a 200 primary shaft. There is a permanent reduction ratio between the 200p shaft of the crankset and the 200 primary shaft

[0048] The primary shaft 200 supports a series of input gears 20 arranged to mesh with a series of output gears 30. The number of input gears 20 and output gears 30 corresponds to the number of ratios of the speed change device, here equal to 7. In the example the input gears 20 are referenced Fri from Fri to Fr7 and the output gears 30 Fi from Fl to F7 according to the selected ratio Gi. The input gears 20 are free and the output gears 30 are fixed relative to an output shaft 230. All the output gears 30 are thus linked to the chain sprocket 955 by the output shaft 230.

[0049] In the context of the present application, the terms "free" and "fixed" respectively mean "free to rotate relative to its axis" and "fixed to rotate relative to its axis" respectively.

[0050] The first primary multiplication pinion 11, the second primary multiplication pinion 12, the input pinions from Fri to Fr7 form here with the output pinions from Fl to F7 the gears of the speed change device 100.

[0051] The torque passes through the free gear Fri which meshes with the output gear Fi corresponding to the selected ratio Gi. The ratio G1 is selected in the example of Figure 3: the free gear Fri which meshes with the output gear Fi. The ratio GI corresponds here to a ratio of 1, without this value being limiting of the invention.

[0052] Finally, the torque is transmitted to the wheel 950 by the crown 955 connected by a chain or a belt.

[0053] Similarly, the torque path Cwa of the electric assistance is represented by dotted lines. The torque coming from the user is the same as previously. However, this time it is associated with that coming from the electric motor 400.

[0054] In the example illustrated, the electric motor 400 is connected to the output pinion F1 corresponding to a ratio GI of the speed change device 100.

[0055] The electric motor 400 is connected to the output pinion F1 via a plurality of pinions 40 of a reducer 400. The plurality of pinions 40 is formed in the example described of five pinions: - a first pinion 41 coaxial with the electric motor 400, - a second pinion 42 meshing with the first pinion, the second pinion 42 being an input pinion of the reducer 300, - a third pinion 43, output pinion of the reducer 400, integral in rotation with the second pinion 42, the third pinion 43 meshing with - a fourth pinion 44, and

[0056] a fifth pinion 45 meshing with said third pinion 43, the fifth pinion 45 being integral in rotation with the fourth pinion.

[0057] A gearshift actuator 150 is arranged to move the shuttle 155 along the selector shaft 200 between 7 positions from Pi to P7 and engage a selected gear.

[0058] The gearshift actuator 150 comprises mechanical means for engaging a gear, for example here a shuttle 155 movable in translation in the selection shaft 200 which is hollow and electrical means for engaging a gear, in particular a geared motor for moving the shuttle 155 between a position Po corresponding to the neutral gear and positions Pi to P7 corresponding to the speed ratios Gi to G7. The shuttle 155 is illustrated in [Fig.3b] in the position Po corresponding to the neutral gear of the speed change device 100. No free gear Fri meshes with an output gear and the movement of the pedal assembly 940 does not allow the wheel 950 to be driven.

[0059] [Fig.5a] schematically illustrates a method P of control according to the invention when implementing reverse gear. The gear change device 100 is in neutral gear. The pedal assembly is not connected to the electric motor 400 nor to the output of the gear change device 100. The user does not provide any useful torque even if he pedals at a pedaling speed Sp corresponding to an input torque Tp of the gear change device 100.

[0060] The useful torque then comes only from the electric motor 400. Even if the user U pedals, the torque produced by the movement of the pedals 940 will not be transmitted to the wheel. The electric motor 400 rotates in the opposite direction, driving the wheel in reverse. The speed and torque are negative here.

[0061] The electric motor 400 rotates at a speed Sm. It is associated with a reducer 300 having a ratio Ra. The output speed of the reducer S'm = Sm / Ra,

[0062] the torque supplied is equal to the engine torque multiplied by the ratio of the reducer 300: T'm = Tm x Ra.

[0063] [Fig.5b] illustrates the steps of the method following a reverse gear instruction from the user in block diagrams. The control unit 800 previously controls the shifting of the gear change device 100 to neutral in a step 803. The control unit controls the actuator 150 of the gear change device so that no free gear 20 of the gear change device is engaged.

[0064] Once the gearshift device 100 is in neutral gear, the control unit 800 controls the electric motor 400 in a step 807 to propel the mobility device 900 in reverse.

[0065] In one embodiment, the transmission assembly comprises a potentiometer connected to the reverse gear control sensor. The user U can thus choose the speed of the electric motor 400 continuously up to a maximum reverse speed value. In a variant, depending on the user's instruction U, the reverse speed of the motor can take one or more discrete values.

[0066] [Fig.6a] schematically illustrates a control method P according to the invention during the implementation of regenerative braking. The gear change device 100 is in neutral gear. The torque path diagram is reversed during the engine braking step. The movement of the wheel 950 rotates the electric motor 400 which functions as a generator and can charge the battery 910 until it is fully charged. The speed and the torque are here in opposite directions. Regenerative braking can in particular be implemented in forward gear, i.e. with a positive speed and a negative engine torque, or in reverse gear, i.e. with a negative speed and a positive engine torque.

[0067] [Fig.6b] illustrates the steps of the method following a braking instruction from the user U. The control unit 800 previously controls the shifting into neutral gear of the gear change device 100 in a step 803. The control unit controls the actuator 150 of the gear change device so that no free gear 20 of the gear change device is engaged.

[0068] Once the gearshift device 100 is in neutral gear, the control unit 800 controls the electric motor 400 in an engine braking step 805.

Claims

Claims

1. Transmission assembly (700) for a mobility device (900), said assembly comprising an electric motor (300) and a gear change device (100) having - a plurality of k ratios between a first ratio (Gl) and a higher ratio called ratio (Gk,) and - a particular reduction ratio (Ri), between an input shaft (200p), arranged to be connected to a pedal assembly (940) of the mobility device, and an output shaft (230) of the gear change device when the ratio (Gi) is engaged, the gear change device having a neutral ratio which, when engaged, does not allow a movement of the pedal assembly (940) to propel the mobility device (900), said assembly comprising a control unit (800) arranged to control the gear change device (100) and the electric motor (300) in reverse mode and / or in braking mode regenerative.said assembly being configured to allow a step (805) of engine braking preceded by a step (803) of engaging neutral gear.

2. An assembly according to claim 1, the electric motor (300) being connected to an output pinion (30, F;) of the speed change device (100).

3. Assembly according to the preceding claim, comprising a reducer (400), the electric motor (300) being connected to said output pinion (30, E) of the speed change device via the reducer (400).

4. Assembly according to any one of the preceding claims, the gear changing device having between 2 and 12 speeds, or even between 5 and 9 speeds.

5. Assembly according to any one of the preceding claims, the control unit (800) being arranged to receive an instruction from a user of the mobility device.

6. A mobility device (900) comprising a transmission assembly according to any one of the preceding claims.

7. Regenerative braking method for mobility device implemented in using a transmission assembly (700) according to one of claims 1 to 5.

8. Regenerative braking method according to the preceding claim comprising a step (805) of engine braking preceded by a step (803) of engaging neutral gear and possibly followed by a step (806) of mechanical braking.

9. A reversing method for a mobility device implemented using a transmission assembly (700) according to one of claims 1 to c

10. J. Reversing method according to the preceding claim comprising a step (807) of controlling the electric motor (300) in the reverse direction, preceded by a step (803) of engaging the neutral gear.

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