Gear-changing device and associated mobility device.

Abstract

The invention relates to a gear-changing device (20) for a mobility device (1) comprising: a selector shaft (40) in which a shuttle (41) and a worm gear (21) are arranged, at least two input pinions (50, Fri) arranged to rotate freely around the selector shaft (40), at least two output pinions (60, Fi) rotationally fixed to a hollow shaft (80), a gear-changing actuator (70) arranged to move the shuttle (41) along the worm gear (21) between at least two positions, and to engage a selected ratio, at least two pawls (42) arranged at the level of the selector shaft ensuring, in one piece, the function of lifting the pawl (42) via the shuttle (41) and the function of engaging the selected ratio via the pawl (42) and the input and output pinions. Figure to be published with the abbreviation: 5

Description

Title of the invention: Gear changing device and associated mobility device.

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

[0002] When operating a mobility device, a driving force is transmitted to the wheels via a crank system rotating around a pedal axle which drives the rear wheel generally by a chain.

[0003] Gearboxes for mobility devices are already known in the prior art. For example, patent application FR2975367 A1 discloses a gear changing device for bicycles comprising a gear box and a sliding shuttle for selecting the gear ratio. The shuttle acts on a ratchet system, via a ball or a spring, which in turn act on input gears to engage the selected gear. The disadvantage of this type of system comes from the fact that it comprises many parts, which complicates its manufacture and assembly and makes it more expensive.

[0004] The present invention therefore aims to overcome one or more of the drawbacks of the devices of the prior art by proposing a simplified speed change device.

[0005] For this purpose, the present invention proposes a gear change device for a mobility device comprising: - a selection shaft in which a shuttle and an endless screw are arranged, - a gearshift actuator arranged to move the shuttle along the worm between at least two positions, and engage a selected gear, - at least two pawls arranged at the level of the selection shaft ensuring in a single piece, the function of lifting the pawl via the shuttle and the function of engaging the selected gear.

[0006] According to one embodiment of the invention, the gear changing device for a mobility device comprises: - a selection shaft in which a shuttle and an endless screw are arranged, - at least two input gears) arranged to rotate freely around the selection tree, - at least two output gears rotating integrally with a hollow shaft, - a gearshift actuator arranged to move the shuttle along the worm screw between at least two positions, and engage a selected gear, - at least two pawls arranged at the level of the selection shaft ensuring in a single piece, the function of lifting the pawl via the shuttle and the function of engaging the selected gear via the input and output gears.

[0007] According to one embodiment of the invention, the pawls have a shape configured to cooperate with the input gears and are arranged in through recesses formed on the selection shaft.

[0008] According to one embodiment of the invention, each pawl is formed in a single piece comprising two parts arranged relative to each other so as to form an angle C of between 60 and 120 degrees.

[0009] According to one embodiment of the invention, the first elongated part is arranged in the recess, perpendicular to the axis of the selection shaft and the second part is arranged at angle C so as to have a face oriented towards the outside of the selection shaft.

[0010] According to one embodiment of the invention, the second part has an enlarged end which allows it to be locked in the recess.

[0011] According to one embodiment of the invention, the first part comprises a stop on which a locking system rests.

[0012] According to one embodiment of the invention, a first end of the locking system is arranged in a groove of the selection shaft so as to be locked in the groove, the return force of the locking system being exerted towards the inside of the selection shaft.

[0013] According to one embodiment of the invention, the groove is formed in the shaft at the end of the second part of the pawl or the first part of the pawl.

[0014] According to one embodiment of the invention, the free end of the first part of the pawl oriented towards the inside of the selection shaft is positioned in the recess so as to protrude towards the inside of the selection shaft.

[0015] The invention also relates to a mobility device, in particular an electrically assisted mobility device, comprising a gear change device according to the invention.

[0016] According to one embodiment of the invention, the machine is an electrically assisted bicycle.

[0017] Other aims, characteristics and advantages of the invention will be better understood and will appear more clearly on reading the description given below, with reference to the appended figures, given by way of example and in which: - [Fig.l] is a view of a mobility device according to one aspect of the invention, - [Fig.2] illustrates the transmission assembly of the mobility device of [Fig.l], - [Fig. 3a and b] illustrates a sectional view of a part of the transmission assembly a) and of the transmission assembly b), - [Fig.4] is a sectional view of a gear changing device according to the invention, - [Fig.5] is a schematic representation seen in section of a part of the gear change device with the locking system of a first variant according to the invention, in dotted lines according to a second position, - [Fig.6] is a schematic representation seen in section of a part of the gear change device with the locking system of a second variant according to the invention, in dotted lines according to a second position, - [Fig.7] is a schematic representation seen in section of a ratchet according to a second variant of the invention, - [Fig.8] is a schematic representation seen in section of a pawl locking element according to the invention, - [Fig.9] is a view of the interior of the housing incorporating part of the transmission assembly according to the invention.

[0018] [Fig.l][Fig.l] 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.

[0019] The bicycle comprises at least two wheels 3, 3' to which a driving force is supplied, by means of two pedals rotating around a crankset axle of axis Xp which drives the rear wheel for example by a chain, or any other means of transmission during its use.

[0020] The machine 1 also comprises a control unit 4 as well as several sensors 5, 5', 5”, located for example at the level of the pedals, on the frame of the bicycle or at the level of a wheel 3, 3'.

[0021] The machine 1 shown here also comprises an energy storage device in the form of a battery 6, a lighting system 7, a pedal assembly 8 with an Xp axis [Fig. 2], a location and / or navigation system 90 as well as a human-machine interface system 91 comprising in particular a touch screen capable of displaying information to and / or take into account the requests of said user. The human-machine interface system 91 is in particular connected to the location 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.

[0022] The wheels 3, 3' are equipped with a braking system 31, including in particular disc brakes 32.

[0023] The machine 1 comprises a transmission assembly 10 illustrated [Fig.2]. The transmission assembly 10 comprises a speed change device 20 according to the invention and the electric motor 2 to provide part of the power for the propulsion of the machine 1.

[0024] According to one embodiment of the invention, the transmission assembly 10 is at least partly housed in a housing 30 (illustrated [Fig.9]) here positioned at the level of the crankset 8 whose axis Xp coincides with the output axis Xv of the speed change device 20.

[0025] According to one embodiment of 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.

[0026] According to one embodiment of the invention, the gear changing device 20 comprises a series of seven output pinions 60 of axis X of reference Fi to F7, integral in rotation with a hollow shaft 80 and a series of seven input pinions 50, of reference Fri to Fr7 arranged to rotate freely around the selection shaft 40.

[0027] According to one embodiment of the invention, the selection shaft 40 illustrated [Fig.4] houses a shuttle 41 surrounding a worm screw 21 of the gear change device 20.

[0028] According to a variant of the invention, the speed change device 20 comprises an epicyclic gear train.

[0029] The machine 1 according to the invention comprises a speed change actuator 70 arranged to move the shuttle 41 along the worm screw 21 by a helical kinematic connection, between at least 2 positions and for example between 7 positions from P i to P7 and engage a selected gear.

[0030] According to one embodiment of the invention, the selection shaft 40 is hollow [Fig.4].

[0031] According to one embodiment of the invention, the gear change actuator 70 comprises electrical means for moving the shuttle 41, in the form of a geared motor. This comprises a motor 81 and a reducer 82.

[0032] According to one embodiment of the invention, the geared motor also comprises a pinion 22 on the axis of the worm screw 21, an intermediate pinion 22' and a pinion 22'” on the axis Xm of the motor 81. The teeth of the pinions 22, 22', 22” can be straight as illustrated or helical in a variant not illustrated.

[0033] The rotational guidance of the worm screw 21 is for example ensured using bearings at each of its ends.

[0034] According to one embodiment of the invention, the shuttle 41 is configured to, during its movement, position itself under the pinion of the selected gear, and engage this gear.

[0035] According to one embodiment of the invention, the shuttle 41 is configured like that described in application FR2975367.

[0036] When changing gear ratio, the worm screw 21 is rotated by the gear change actuator 70, causing axial movement of the nut 210 of the screw 21 which drives the shuttle 41 and thus allows gear changing. Thanks to the pivot connection thus produced, the rotational movement of the worm screw 21 is transformed into translational movement of the shuttle 4L.

[0037] According to one embodiment of the invention, the geared motor comprises pinions with parallel axes as illustrated [Fig.3] or with perpendicular axes.

[0038] According to one embodiment of the invention, the gear change actuator 70 comprises a bevel, straight or helical gear and / or with one or more stages.

[0039] According to an alternative embodiment of the invention, the gear change actuator 70 has a belt or a chain or a universal joint.

[0040] According to an embodiment of the invention, illustrated [Fig.5] and [Fig.8], the gear change device 20 comprises at the level of the selection shaft 40 at least two pawls 42 and for example for a 7-speed engine 1, comprises seven pawls 42.

[0041] 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.

[0042] According to one embodiment of the invention, the gear changing 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.

[0043] According to one embodiment of the invention, the gear changing device 20 comprises two series of at least seven pawls arranged one after the other along the longitudinal axis X2 of the selection shaft 40. The series being arranged at 180 degrees from each other around the selection shaft 40.

[0044] According to one embodiment of the invention, the gear changing device 20 comprises three series of at least seven pawls arranged one after the other along the longitudinal axis X2 of the selection shaft 40. The series are arranged at 120 degrees from each other around the selection shaft 40.

[0045] The pawls 42 have a shape configured to cooperate with the input gears Fri. The pawls 42 are arranged in through recesses 420 formed on the selection shaft 40.

[0046] According to an embodiment of the invention illustrated [Fig.7], each pawl 42 is formed in a single piece comprising two parts 421, 422 arranged relative to each other so as to form an angle C of between 60 and 120 degrees. This single-piece pawl avoids the use of several parts.

[0047] According to one embodiment of the invention, the two parts have a tubular or square shape or any other shape compatible with their function. A first part 421 of elongated shape is arranged in the recess 420, perpendicular to the axis X2 of the selection shaft, when the gear is not engaged. A second part is arranged at the angle C so as to have a face oriented towards the outside of the selection shaft 40 illustrated [Fig.5] and [Fig.6]. The outside of the shaft being the face opposite that in contact with the worm screw 21 and located inside.

[0048] According to one embodiment of the invention, the second part 422 has an enlarged end 424 which allows it to be locked in the recess. The enlarged end 424 has a rounded shape to allow rotation of the pawl 42 in the recess.

[0049] The free end 425 of the first part 421 oriented towards the inside of the selection shaft 40, is positioned in the recess so as to protrude towards the inside of the selection shaft 40.

[0050] According to one embodiment of the invention, the pawl is held in place by a radial locking system 44 illustrated [Fig.5], [Fig.6] and [Fig.8]. That is to say a system 44 which keeps the pawls 42 pressed in their housing, while allowing them to be lifted via the shuttle 4L

[0051] According to one embodiment of the invention, the locking system is formed from a single piece. This facilitates its assembly, its manufacture and limits costs.

[0052] According to one embodiment of the invention, the locking system 44 comprises a longitudinal flat part 440.

[0053] According to one embodiment of the invention, the system 44 comprises at least two tabs 441, and for example seven tabs 441 in the case of a seven-speed machine.

[0054] According to one embodiment of 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 to the axis Xb of the locking system 44. The locking system 44 thus forms a comb with flattened and spaced teeth.

[0055] According to one embodiment of 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, and parallel to the axis of the shaft, formed in the selection shaft 40.

[0056] According to one embodiment of the invention, this second edge 443 is folded towards the shaft 40 to fit into the groove 45.

[0057] The locking system 44 is arranged on the selection shaft 40 so that each tab 441 is positioned on a ratchet 42.

[0058] According to one embodiment of the invention, each pawl 42 comprises a recess 421 whose shape is complementary to that of the tongue 42 so that the tongue 42 is housed in the recess 421 of the pawl, and does not move when the pawl is locked.

[0059] According to one embodiment of the invention, the rotation locking device 44 comprises a positioning tab 446. This positioning tab 446 is arranged on the second edge 443 inserted in the groove 45. This tab 446 cooperates with an additional housing 445 of a shape complementary 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.

[0060] The rotational locking system 44 presses on the pawl 42 so as to keep it pressed in the recess towards the inside of the selection shaft 40, while allowing it to be lifted via the shuttle 4L. According to one embodiment, the return force F of the locking system 44 is exerted towards the inside of the selection shaft 40.

[0061] According to one embodiment of the invention, the gear change system comprises at least two or three rotational locking systems 44 arranged so as to lock two or three series of pawls.

[0062] Thus the pawl 42 is pressed into the recess towards the inside of the selection shaft 40, and held in place by the return force of the locking system 44, and will lift (in dotted lines on [Fig.6]) as the shuttle 4L passes.

[0063] According to a first variant of the invention [Fig. 6], the groove 45 is formed in the shaft 40 at the end of the second part 422 of the pawl 42. That is to say on the side of the enlarged part 422 424. The locking element 44 is thus inserted at this level by its first edge 443.

[0064] According to an embodiment of this first variant, the insertion is carried out in the longitudinal groove 45, and parallel to the axis of the shaft, formed in the selection shaft 40 so as to form an angle greater than 0 degrees with the end of the second part 422 of the pawl 42 along a radial plane.

[0065] According to a second variant of the invention, the groove 45 is formed in the shaft 40 at the level of the first part 421 of the pawl 42. That is to say on the side of the free part of the pawl which is lifted under the action of the shuttle. The system 44 is thus inserted at this level by its first edge 443.

[0066] This second variant makes it possible to limit the force exerted on the locking element. and thus limits the risk of deterioration of the locking system.

[0067] According to an embodiment of this second variant, the insertion is carried out in the longitudinal groove 45, and parallel to the axis of the shaft, formed in the selection shaft 40 so as to form an angle greater than 0 degrees with the first part 421 of the pawl 42 along a radial plane.

[0068] According to a variant of this second variant illustrated [Fig.5] and [Fig.7], the first part 421 of the pawl 42 comprises a stop 423 on which the locking element bears. The stop is arranged opposite the second part 422 in the same radial plane.

[0069] The free end 441, that is to say the one which is not inserted into the groove, bears on the stop 423 of the pawl 42 so as to keep it pressed in the recess towards the inside of the selection shaft 40, while allowing it to be lifted via the shuttle 4L. More precisely, the return force F of the locking system 44 is exerted towards the inside of the selection shaft 40.

[0070] Such a ratchet according to the invention thus provides two functions in a single piece, the lifting function via the shuttle and the function of engaging the selected gear via the ratchet. This facilitates its manufacture, assembly and reduces costs.

[0071] When the speed is selected, the shuttle 41 is positioned under the input pinion Fq corresponding to the selected ratio i, which is then locked in rotation by the lifting of one of the pawls 42, and meshes with the corresponding output pinion Fi.

[0072] If the machine 1 is running in a ratio i, without changing it, the worm screw 21 does not turn.

[0073] According to one embodiment of the invention, a stop 211, 211' limits at each end the movement of the shuttle 4L. According to another embodiment of the invention, the movement of the shuttle is controlled by a position sensor.

[0074] According to an embodiment not illustrated, the shuttle 41 is capable of taking a position called the neutral position PO for which no gear ratio is engaged.

[0075] [Fig.9] illustrates in more detail the housing 30 of the mobility device I of [Fig.l].

[0076] The housing 30 comprises a casing 310 delimiting a first housing 311 arranged to house the gears of the speed change device 20. The casing 310 also delimits at least two second housings 312, 313, 314, 315, distinct from each other. All of these housings are arranged to respectively house the electric motor 2, the reducer 11, the speed change actuator 70 and the control unit 4 of the mobility device. According to one embodiment of the invention, at least one second housing is sealed, and for example that arranged to contain the control unit 4.

[0077] According to one embodiment of the invention, the casing 310 housing the gear change device 20 is closed by two lateral flanges 317. The first housing 311 has two openings opposite each other in the side plates 317 to accommodate the pedal axle of the mobility device 1.

[0078] The scope of the present invention is not limited to the details given above and allows embodiments in many other specific forms without departing from the scope of the invention. Therefore, the present embodiments should be considered by way of illustration, and may be modified without departing from the scope defined by the claims.

Claims

Claims

1. Gear change device (20) for a mobility device (1) comprising: - a selection shaft (40) in which a shuttle (41) and a worm screw (21) are arranged, - a gear change actuator (70) arranged to move the shuttle (41) along the worm screw (21) between at least two positions, and engage a selected gear, - at least two pawls (42) arranged at the selection shaft ensuring in a single piece, the function of lifting the pawl (42) via the shuttle (41) and the function of engaging the selected gear.

2. A gear changing device (20) according to claim 1, wherein each pawl (42) is formed in a single piece comprising two parts (421, 422) arranged relative to each other so as to form an angle C of between 60 and 120 degrees.

3. A gear changing device (20) according to claim 2, wherein the first elongated portion (421) is arranged in a recess, perpendicular to the axis X2 of the selection shaft (40) and the second portion is arranged at the angle C so as to have a face facing outwardly of the selection shaft (40).

4. A gear shift device (20) according to claim 3, wherein the second portion (422) has an enlarged end (424) which allows it to be locked in the recess.

5. Gear changing device (20) according to one of claims 2 to 4, in which the first part (421) comprises a stop (423) on which a locking system (44) bears.

6. A gear changing device (20) according to claim 5, wherein a first end (443) of the locking system (44) is arranged in a groove (45) of the selection shaft (40) so as to be locked in the groove (45), the restoring force F of the locking system (44) being exerted towards the inside of the selection shaft (40).

7. A speed change device (20) according to claim 6, wherein the groove (45) is formed in the shaft (40) at the end of the second part (422) of the ratchet (42) or of the first part (421) of the ratchet (42).

8. Gear changing device (20) according to one of claims 2 to 7, wherein the free end (425) of the first part (421) of the pawl (42) facing towards the inside of the selection shaft (40), is positioned in the recess so as to protrude towards the inside of the selection shaft (40).

9. Mobility device (1), in particular electrically assisted mobility device, comprising a gear changing device (20) according to any one of the preceding claims.

10. Mobility device according to claim 9, in which the device (1) is an electrically assisted bicycle.

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