Gearshift device and associated mobility vehicle

Description

[0001] The present invention relates to the field of gear changing devices, and more particularly a gear changing device for a mobility device using at least one electric propulsion of the electric assist bicycle type.

[0002] During the operation of a mobility device, a driving force is transmitted to the wheels via a crank system rotating around a bottom bracket axle which drives the rear wheel usually by a chain.

[0003] It is already known in the prior art of gearboxes for mobility devices. For example, patent application FR2975367 A1 discloses a bicycle gear-changing device comprising a geared gearbox and a sliding shuttle for selecting the gear ratio. The axial movement of the shuttle is controlled by two cables connected to a rotating handlebar grip. This system requires numerous parts. Its manufacture and maintenance are complex. In particular, the cable control requires precise and regular adjustments.

[0004] DE 10 2017 008 376 B3 discloses a foot-operated gear-shifting device for vehicles, said device comprising: a selector shaft in which a shuttle and a worm gear are arranged, at least two output gears arranged to rotate freely around the selector shaft, at least two input gears fixed in rotation to a hollow shaft, a gear-changing actuator arranged to move the shuttle along the worm gear between at least two positions, and engage a selected ratio, at least two pawls arranged at the selector shaft, each pawl being associated with a lifting device allowing the pawl to be lifted via the shuttle, and to engage the selected ratio via the associated input and output gears, and at least one radial locking system to hold all the pawls of a series in place on the selector shaft.

[0005] There is a need to simplify and automate gearboxes for cycles.

[0006] For this purpose, the present invention proposes a gear-changing device for a mobility device of the type electric-assisted bicycle defined in claim 1. Preferred embodiments of the invention are defined in the dependent claims.

[0007] The radial locking system thus formed from a single piece has its assembly and manufacture facilitated, its costs are also reduced.

[0008] According to the invention, the locking system consists of a longitudinal flat part from which at least two tabs extend, each of the tabs being positioned above a ratchet.

[0009] According to the invention, the tabs are formed from a first edge, parallel to the axis of the locking system, of the flat part and oriented perpendicularly with respect to the axis of the locking system.

[0010] According to the invention, the flat part is inserted, via a second edge opposite to that where the tabs are located, into a longitudinal groove formed in the selection shaft.

[0011] According to one embodiment of the invention, the second edge is folded towards the shaft to fit into the groove.

[0012] According to one embodiment of the invention, each ratchet has a recess whose shape is complementary to that of the associated tab so that the tab is housed in the recess.

[0013] According to one embodiment of the invention, the gear changing device comprises seven input and output gears, seven pawls and seven tabs.

[0014] According to one embodiment of the invention, the locking device includes a positioning tab.

[0015] The invention also relates to an electrically assisted mobility device, of the electric-assisted bicycle type, comprising a gear-changing device according to the invention,

[0016] According to one embodiment of the invention, the device is an electrically assisted bicycle. Other objects, features, and advantages of the invention will be better understood and will become clearer upon reading the description below, with reference to the accompanying figures, given by way of example, in which: there [ Fig. 1 ] is a view of a mobility device according to one aspect of the invention, the [ Fig. 2 ] illustrates the entire transmission system of the mobility device of the Figure 1 , THE [ Fig. 3a and b] illustrates a cross-sectional view of part of transmission assembly a) and transmission assembly b), the [ Fig. 4 ] is a cross-sectional view of a gear-changing device according to the invention, the [ Fig. 5 ] is an elevational view of a portion of the gear-changing device with a locking system according to the invention, the [ Fig. 6 ] set a cross-sectional view of a portion of the gear-changing device with the locking system according to the invention, the [ Fig. 7 ] is a view of the inside of the housing incorporating part of the transmission assembly according to the invention.

[0017] There figure 1 [Fig. 1 [ ] illustrates a mobility device 1 according to one aspect of the invention. The device 1 is here an electrically assisted bicycle comprising an electric motor 2. The electric motor 2 is arranged to provide part of the propulsion of the device.

[0018] The bicycle has at least two wheels 3, 3' to which a driving force is supplied, via two pedals rotating around a bottom bracket axle Xp which drives the rear wheel for example by a chain, or any other means of transmission during its use.

[0019] The device 1 also includes a control unit 4 as well as several sensors 5, 5', 5", located for example at the level of the pedal assembly, on the bicycle frame or at the level of a wheel 3, 3'.

[0020] The device 1 shown here also includes an energy storage device in the form of a battery 6, a lighting system 7, a crankset 8 with an Xp axis, a localization and / or navigation system 90, and a human-machine interface system 91 comprising, in particular, a touchscreen capable of displaying information and / or responding to user requests. The human-machine interface system 91 is specifically connected to the localization system 90 and serves as a navigation interface. The invention is not limited to a particular human-machine interface system and may include any system known to those skilled in the art.

[0021] The wheels 3, 3' are equipped with a braking system 31, including disc brakes 32.

[0022] The unit 1 comprises a transmission assembly 10 illustrated [ Fig. 2 The transmission assembly 10 includes a gear-changing device 20 according to the invention and the electric motor 2 to provide part of the power for the propulsion of the machine 1.

[0023] According to one embodiment of the invention, the transmission assembly 10 is at least partly housed in a casing 30 (illustrated [ Fig. 7 ]) here positioned at the level of the pedal assembly 8 whose axis Xp coincides with the output axis X v of the gear changing device 20.

[0024] According to the invention, the gear-changing device 20 illustrated [ Fig. 3 a and b] has at least 2 ratios, and for example 7 ratios between a first ratio called ratio no. 1 and a higher ratio called ratio no. 7.

[0025] According to one embodiment of the invention, the gear change device 20 comprises a series of seven output gears 60 with axis X v, of reference F 1 to F 7, fixed in rotation to a hollow shaft 80 and a series of seven input gears 50, of reference Fr 1 to Fr 7 arranged to rotate freely around the selection shaft 40.

[0026] According to one embodiment of the invention, the selection tree 40 illustrated [ Fig. 3 ] And [ Fig. 4 ] houses a shuttle 41 surrounding a worm gear 21 of the speed change device 20. According to a variant of the invention, the speed change device 20 comprises an epicyclic gear train.

[0027] The device 1 according to the invention, includes a speed change actuator 70 arranged to move the shuttle 41 along the worm screw 21 by a helical kinematic linkage, between at least 2 positions and for example between 7 positions from P 1 to P 7 and engage a selected ratio.

[0028] According to one embodiment of the invention, the selection tree 40 is hollow.

[0029] According to one embodiment of the invention, the speed change actuator 70 comprises electrical means for moving the shuttle 41, in the form of a geared motor. This includes a motor 81 and a gearbox 82.

[0030] According to one embodiment of the invention, the geared motor also includes a pinion 22 on the shaft of the worm gear 21, an intermediate pinion 22' and a pinion 22‴ on the shaft of the motor 81. The teeth of the pinions 22, 22', 22" can be straight as illustrated or helical in a variant not illustrated.

[0031] The rotational guidance of the worm screw 21 is, for example, ensured by means of bearings at each of its ends.

[0032] According to one embodiment of the invention, the shuttle 41 is configured so that, during its movement, it positions itself under the pinion of the selected gear and engages that gear. According to another embodiment of the invention, the shuttle 41 is configured as described in application FR2975367.

[0033] According to one embodiment of the invention, the geared motor comprises parallel axis gears as illustrated [ Fig. 3 ] or perpendicular axes.

[0034] According to one embodiment of the invention, the speed change actuator 70 comprises a bevel gear, straight or helical and / or with one or more stages.

[0035] According to one embodiment of the invention, the gear shift actuator 70 has a belt or a chain or a cardan joint.

[0036] According to the invention, illustrated [ Fig. 5 ] And [ Fig. 6 ], the gear changing device 20 has at the level of the selection shaft 40 at least two pawls 42 and for example for a 1 to 7 speed engine, has seven pawls 42.

[0037] According to one embodiment of the invention, the gear change device 20 comprises a series of seven pawls arranged one after the other along the longitudinal axis X2 of the selection shaft 40.

[0038] According to one embodiment of the invention, the gear change device 20 comprises at least one series of at least seven pawls arranged one after the other along the longitudinal axis X2 of the selection shaft 40.

[0039] According to one embodiment of the invention, the gear change device 20 comprises three sets of at least seven pawls arranged one after the other along the longitudinal axis X2 of the selection shaft 40. The sets being arranged at 120 degrees to one another around the selection shaft 40.

[0040] The pawls 42 have a shape configured to cooperate with the input pinions Fri. The pawls 42 are arranged in recesses 420 formed on the selector shaft 40. Each pawl 42 is associated with a lifting device, and for example a ball 43, visible [ Fig. 4 ] And [ Fig. 6 ] disposed in a bore 430 of the inner shaft, protruding inside the inner shaft, placed under each pawl 42 so as to be able to lift it via the shuttle 41.

[0041] When the speed is selected, the shuttle 41 is positioned under the input pinion Fr I corresponding to the selected ratio i, which is then blocked in rotation by one of the pawls 42, and meshes with the corresponding output pinion.

[0042] In the context of the invention, to hold the pawls 42 in place within their housing 420, the gear-shifting system includes at least one radial locking system 44 formed in a single piece. That is to say, a system 44 that holds the pawls 42 securely in their housing, while allowing them to be lifted by means of the ball 43 and the shuttle 41. The radial locking system 44 is formed in a single piece. This simplifies its assembly and manufacture and reduces costs.

[0043] According to the invention, the locking system 44 comprises a longitudinal flat part 440.

[0044] According to the invention, the system 44 comprises at least two tabs 441, and for example seven tabs 441 in the case of a seven-speed engine.

[0045] According to the invention, the tabs 441 are formed from a first edge 442, parallel to the axis Xb of the locking system 44, of the flat part 440 and oriented perpendicularly with respect to the axis Xb of the locking system 44. The rotating locking system 44 thus forms a comb with flattened and spaced teeth.

[0046] According to the invention, the flat part 440 is inserted, via a second edge 443 opposite that 442 where the tabs 441 are located, into a longitudinal groove 45, parallel to the axis of the shaft, formed in the selection shaft 40.

[0047] According to one embodiment of the invention, this second edge 443 is folded towards the shaft 40 to fit into the groove 45.

[0048] The locking system 44 is arranged on the selection shaft 40 so that each tab 441 is positioned on a ratchet 42.

[0049] According to one embodiment of the invention, each ratchet 42 has a recess 421 whose shape is complementary to that of the tongue 441 so that the tongue 441 is housed in the recess 421, and does not move when the ratchet is locked.

[0050] According to one embodiment of the invention, the rotation-locking device 44 comprises a positioning tab 446. This positioning tab 446 is disposed on the second edge 443 inserted in the groove 45. This tab 446 cooperates with an additional housing 445 of complementary shape to that of the positioning tab 446 formed in the selection shaft 40. This positioning tab 446 allows the tabs 441 of the device to be centered above the pawls 42.

[0051] The rotation locking system 44 thus exerts on each pawl 42 a pressure, or clamping force, sufficient to lock the pawl 42 in the housing 421 while allowing it to be lifted by the shuttle 41.

[0052] According to one embodiment of the invention, the gear change system comprises at least three rotation locking systems 44 arranged to lock three sets of pawls.

[0053] The shuttle 41 allows the selected ratio to be selected, which will engage an input pinion Fri via a ratchet 42 and be locked in rotation by means of the rotation locking system 44.

[0054] The input pinion Fri then meshes with an output pinion Fi.

[0055] If the machine 1 travels in a ratio i, without changing it, the worm gear 21 does not turn.

[0056] During a gear change, the worm gear 21 is rotated by the gear shift actuator 70, causing axial movement of the nut 210 of the worm gear 21, which in turn drives the shuttle 41 and thus enables the gear change. Thanks to the pivot joint thus created, the rotational movement of the worm gear 21 is transformed into a translational movement of the shuttle 41.

[0057] According to one embodiment of the invention, a stop 211, 211' limits the movement of the shuttle 41 at each end. According to another embodiment of the invention, the movement of the shuttle is controlled by a position sensor.

[0058] According to an embodiment not illustrated, the shuttle 41 is capable of taking a position called neutral position P0 for which no speed ratio is engaged.

[0059] There [ Fig. 7 ] illustrates in more detail the housing 30 of the mobility device 1 of the figure 1 .

[0060] The housing 30 comprises a casing 310 defining a first compartment 311 arranged to house the gears of the speed-changing device 20. The casing 310 also defines at least two second compartments 312, 313, 314, 315, distinct from one another. All of these compartments are arranged to house, respectively, the electric motor 2, the gearbox 11, the speed-changing actuator 70, and the control unit 4 of the mobility device. According to one embodiment of the invention, at least one second compartment is sealed, for example, the one arranged to contain the control unit 4.

[0061] According to one embodiment of the invention, the housing 310 containing the gear-changing device 20 is closed by two side flanges 317, only one of which is illustrated in the figure 4The first housing 311 has two facing openings in the side flanges 317 to accommodate the pedal axle of the mobility device 1.

[0062] The scope of the present invention is not limited to the details given above and allows for embodiments in many other specific forms without departing from the field of application of the invention. Therefore, the present embodiments should be considered illustrative only and may be modified without departing from the scope defined by the claims.

Claims

1. Gear-shifting device (20) for a mobility vehicle (1) of the electric-assist bicycle type comprising: - a selection shaft (40) in which a shuttle (41) and a worm screw (21) are arranged, - at least two input sprockets (50, Fri) arranged to rotate freely around the selection shaft (40), - at least two output sprockets (60, Fi) rotationally secured to a hollow shaft 2 (80), - a gear-shifting actuator (70) arranged to move the shuttle (41) along the worm screw (21) between at least two positions, and to engage a selected gear ratio, - at least two pawls (42) arranged at the level of the selection shaft (40), each pawl (42) being associated with a lifting device (43) enabling the pawl to be lifted via the shuttle (41), and to engage the selected gear ratio via the associated input and output sprockets, and - at least one radial locking system (44), formed as a single piece, for holding all of the pawls (42) of a series in place on the selection shaft (40), wherein the locking system (44) is formed of a longitudinal planar portion (440) from which at least two tabs (441) extend, each of the tabs (441) being positioned above one of the pawls (42) of the series and formed from a first edge (442), parallel to the axis (Xb) of the locking system (44), of the planar portion (440) and oriented perpendicularly with respect to the axis (Xb) of the locking system (44), the planar portion (440) being inserted, via a second edge (443) opposite to the one (442) where the tabs (441) are located, into a longitudinal groove (45) formed in the selection shaft (40).

2. Gear-shifting device (20) according to claim 1, wherein the second edge (443) is folded in the direction of the selection shaft (40) so as to be inserted into the groove (45).

3. Gear-shifting device (20) according to claim 1 or 2, wherein each pawl (42) comprises a recess (421) whose shape is complementary to that of the associated tab (441) such that the tab (441) is housed within the recess (421).

4. Gear-shifting device (20) according to one of claims 1 to 3, comprising seven input sprockets (50) and output sprockets (70), seven pawls (42) and seven tabs (441).

5. Gear-shifting device (20) according to one of claims 1 to 4, wherein the radial locking system (44) comprises a positioning tab (446).

6. Electric-assist mobility vehicle (1), of the electric-assist bicycle type, comprising a gear-shifting device (20) according to any one of the preceding claims.

7. Mobility vehicle according to claim 6, wherein the vehicle (1) is an electric-assist bicycle.