Gear-changing device and associated mobility device.

Abstract

The invention relates to a gear change device (20) for a mobility device (1) comprising: a selector shaft (40) in which a shuttle (41) and a worm gear (21) are disposed, a gear change actuator (70) arranged to move the shuttle (41) along the worm gear (21) between at least two positions, and engage a selected ratio, at least two pawls (42) disposed at the level of the selector shaft (40). The shuttle allows the lifting of a pawl to engage the selected gear, each pawl having a first part (421) inserted into the shaft (40) and a second part (422), a radial locking system (44), formed in one piece, for holding all the pawls (42) in place on the selector shaft (40), characterized in that the locking system is disposed at the first part (421) of the pawl (42). 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 ratchets are held by a locking system. A disadvantage of these systems comes from their fragility linked to the force required to hold the ratchets in place.

[0004] The present invention therefore aims to overcome one or more of the drawbacks of the devices of the prior art by proposing an improved 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, the shuttle allowing the lifting of a pawl to engage the selected gear, each pawl having a first part inserted in the shaft and a second part, - a locking system, formed from a single piece, to hold all the pawls in place on the selection shaft, the locking system being arranged at the level of the first part of the pawl.

[0006] According to one embodiment of the invention, the locking system is arranged in

[0007]

[0008]

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[0010]

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[0012]

[0013]

[0014] a groove. According to one embodiment of the invention, the groove is formed in the shaft at the first part of the pawl. According to one embodiment of the invention, the groove is longitudinal, and parallel to the axis of the shaft, formed in the selection shaft so as to form an angle greater than 0 degrees with the first part of the pawl. According to one embodiment of the invention, the locking system is formed of a longitudinal flat part from which at least two tabs extend, each of the tabs being positioned above a ratchet. According to one embodiment of 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 to the axis of the locking system. According to one embodiment of the invention, the flat part is inserted, via a second edge opposite that where the tabs are located, into the longitudinal groove formed in the selection shaft. The invention also relates to a mobility device, in particular an electrically assisted mobility device, comprising a gear change device according to the invention. According to one embodiment of the invention, the machine is an electrically assisted bicycle 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 according to the invention, in dotted lines according to a second position, - [Fig.6] is a schematic representation seen in section of a locking element of the ratchet according to the invention, - [Fig.7] is a schematic representation seen in section of a ratchet according to a variant of the invention, - [Fig.8] is a schematic representation seen in section of a ratchet according to another variant of the invention, - [Fig.9] is a view of the interior of the housing incorporating part of the transmission assembly according to the invention.

[0015] [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.

[0016] 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.

[0017] 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'.

[0018] 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, a location and / or navigation system 90 and a human-machine interface system 91 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 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 comprise any system known to those skilled in the art.

[0019] The wheels 3, 3' are equipped with a braking system 31, including in particular disc brakes 32.

[0020] 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.

[0021] 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.

[0022] According to one embodiment of the invention, the gear change device 20 illustrated [Fig. 3 a and b] comprises 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.

[0023] According to one embodiment of the invention, the speed change 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.

[0024] According to one embodiment of the invention, the selection shaft 40 illustrated [Fig.3] and [Fig.4] houses a shuttle 41 surrounding a worm screw 21 of the gear change device 20.

[0025] According to a variant of the invention, the speed change device 20 comprises an epicyclic gear train.

[0026] 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.

[0027] According to one embodiment of the invention, the selection shaft 40 is hollow.

[0028] 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.

[0029] 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.

[0030] The rotational guidance of the worm screw 21 is for example ensured using bearings at each of its ends.

[0031] 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.

[0032] According to one embodiment of the invention, the shuttle 41 is configured like that described in application FR2975367.

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

[0034] 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.

[0035] According to an alternative embodiment of the invention, the gear change actuator 70 has a belt or a chain or a universal joint.

[0036] According to an embodiment of the invention, illustrated [Fig.5] and [Fig.6], 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.

[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 changing device 20 comprises at least one series of at least seven ratchets 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 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 being arranged at 120 degrees from each other around the selection shaft 40.

[0040] 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.

[0041] According to one embodiment of the invention, the pawls 42 have a shape configured to cooperate with the input gears Fri. The pawls 42 are arranged in recesses 420 formed on the selection shaft 40.

[0042] According to one embodiment of the invention, each pawl 42 is associated with a spring arranged 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 4L

[0043] According to a variant of the invention, each pawl 42 is associated with at least one lifting device, and for example a ball 43, visible [Fig.7] arranged 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 4L

[0044] According to a second variant of the invention, illustrated [Fig.8], 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.

[0045] 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. The outside of the shaft being the face opposite that in contact with the worm screw 21 and located inside.

[0046] 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.

[0047] 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 tree 40.

[0048] According to a variant of this second variant, the first part 421 of the pawl 42 comprises a stop 423 on which a locking element bears. The stop is arranged opposite the second part 422 in the same radial plane.

[0049] Such a ratchet according to the invention thus provides two functions in a single part, the lifting function via the shuttle and the function of engaging the selected gear via the ratchet.

[0050] 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 one of the pawls 42, and meshes with the corresponding output pinion.

[0051] In the context of the invention, to hold the pawls 42 in place in their housing 420, the gear change system comprises at least one radial locking system 44 formed from a single piece. That is to say a system 44 which holds the pawls 42 pressed in their housing, while allowing them to be lifted via the ball 43 and the shuttle 4L. The radial locking system 44 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 in rotation 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, and does not move when the pawl is locked.

[0059] According to an embodiment of the invention of the second variant, 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 41. More precisely, the return force F of the locking system 44 is exerted towards the inside of the selection shaft 40.

[0060] According to one embodiment of the invention, the rotation locking device 44 comprises a positioning tab 444. This positioning tab 444 is arranged on the second edge 443 inserted in the groove 45. This tab 444 cooperates with an additional housing 445 of a shape complementary to that of the positioning tab 444 formed in the selection shaft 40. This positioning tab 4444 allows the tabs 441 of the device to be centered above the pawls 42.

[0061] The rotation locking system 44 thus exerts on each pawl 44 a pressure, or pressing force, sufficient to lock the pawl 42 in the housing 421 while allowing it to be lifted by the shuttle 41.

[0062] In the context of the invention, the visible groove 45 [Fig. 5] 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.

[0063] This makes it possible to limit the force exerted on the locking element and thus limits the risk of damage.

[0064] According to one embodiment of the invention, 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.

[0065] 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.

[0066] The shuttle 41 makes it possible to select the chosen ratio which will engage an input pinion Fri via a ratchet 42 and be locked in rotation thanks to the rotation locking system 44.

[0067] The input gear Fri then meshes with an output gear Fi.

[0068] If the engine 1 is running in a gear i, without changing it, the worm screw 21 does not turn.

[0069] When changing gear ratio, the worm screw 21 is driven in rotation by the gear change actuator 70 causing the axial movement of the nut 210 of the screw 21 which drives the shuttle 41 and thus allows the gear change. Thanks to the pivot connection thus produced, the rotational movement of the worm screw 21 is transformed into translational movement of shuttle 41.

[0070] 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.

[0071] 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.

[0072] [Fig.9] illustrates in more detail the housing 30 of the mobility device I of [Fig.l].

[0073] 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.

[0074] 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 facing each other in the lateral flanges 317 to accommodate the pedal axle of the mobility device 1.

[0075] 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 (40), the shuttle allowing the lifting of a pawl to engage the selected gear, each pawl having a first part (421) inserted in the shaft (40) and a second part (422), - a radial locking system (44), formed in a single piece, to hold all of the pawls (42), in place on the selection shaft (40), characterized in that the locking system is arranged at the first part (421) of the ratchet (42).

2. A gear changing device (20) according to claim 1, wherein the locking system (44) is arranged in a groove (45).

3. A gear shift device (20) according to claim 2, wherein the groove (45) is formed in the shaft (40) at the first portion (421) of the pawl (42).

4. Gear changing device (20) according to one of claims 2 to 3, wherein the groove (45) is longitudinal, 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).

5. Gear changing device (20) according to one of claims 1 to 4, wherein the locking system (44) is formed of a longitudinal flat part (440) from which at least two tabs (441) extend, each of the tabs (441) being positioned above a pawl (42).

6. A gear shift device (20) according to claim 5, wherein 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).

7. Gear changing device (20) according to one of claims 5 to 6, in which the flat part (440) is inserted, via a second edge (443) opposite that (442) where the tabs (441) are located, into the longitudinal groove (45) formed in the selection shaft (40).

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

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

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