Gear-changing device and associated mobility device.

Abstract

The invention relates to a Gear Change Device (20) for a mobility device (1) comprising: a selection shaft (40) in which are disposed a shuttle (41) and a worm gear (21), the shuttle 41 comprising a cylindrical body (26) having, at its periphery, longitudinal channels (27) extending over its entire length and, at the center, a transverse channel (29) into which are inserted two transverse fins (35) of a tab (25) intended to retain a thrust means (33), a gear change 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) disposed at the level of the selection shaft (40).Each pawl (42) is associated with a lifting device (43) which is associated with the thrust means (33) allowing the pawl to be lifted via the shuttle (41), and the selected gear to be engaged via input and output gears. The shuttle (41) includes means (281, 282) for retaining the transverse fins (35) in the transverse channel (29). Figure to be published with the abbreviation: 9.

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 electric-assisted bicycle.

[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 generally by a chain.

[0003] Gear-changing devices for mobility equipment are already known in the prior art. These gear-changing devices comprise a gearbox in which a shuttle is configured to, during its movement, position itself under a gear of a selected ratio and engage that ratio via a ratchet. Such a device requires numerous parts. Its manufacture and maintenance are complex.

[0004] The present invention therefore aims to overcome one or more of the drawbacks of prior art devices by proposing a simplified transmission assembly for mobility equipment.

[0005] To this end, the present invention proposes a gear-changing device for a mobility device comprising:

[0006] Gear-changing device for a mobility device comprising: - a selection shaft in which a shuttle and a worm gear are arranged, the shuttle comprising a cylindrical body having, at its periphery, longitudinal channels extending over its entire length and, at the center, a transverse channel into which are inserted two transverse fins of a tab intended to retain a thrusting means, - a gear-change actuator arranged to move the shuttle along the worm gear between at least two positions, and engage a selected gear, - at least two pawls arranged on the selection shaft, each pawl being associated with a lifting device linked to the thrust means allowing the pawl to be lifted via the shuttle, and the selected ratio to be engaged via input and output gears,

[0007] the shuttle comprising means for retaining the transverse fins in the transverse channel.

[0008] These means make it possible to maintain the necessary elasticity of the tongue to cooperate with the spring-type pushing means.

[0009] According to one embodiment of the invention, the means for retaining the transverse fins comprise two lateral edges at their end.

[0010] According to one embodiment of the invention, the means for retaining the transverse fins comprise two lateral edges at their end cooperating with two stops formed in each transverse channel.

[0011] According to one embodiment of the invention, the shuttle is made of steel or polymer.

[0012] According to one embodiment of the invention, the shuttle is made of plastic and incorporates a dedicated lip to hold a ball bearing in position.

[0013] The invention also relates to a mobility device, in particular an electrically assisted mobility device, comprising a gear-changing device according to the invention.

[0014] According to one embodiment of the invention, the device is an electrically assisted bicycle

[0015] Other objects, features and advantages of the invention will be better understood and will become more apparent upon reading the description given below, with reference to the accompanying figures, given by way of example and in which: - Figure [1] 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.1], - Figure 3 illustrates a cross-sectional view of part of the assembly transmission according to an embodiment of the invention, - Figure 4 illustrates a cross-sectional view of another part of the transmission assembly according to one embodiment of the invention, - Figure 5 is an elevational view of the ratchet system according to the invention. - Figure 6 is a cross-sectional view of a ratchet system according to the invention. - Fig. 7 is an elevation view of the housing closure system a gear-changing device according to the invention, or according to another embodiment of the invention. - [Fig.8] is a cross-sectional view of part of the output shaft, - Fig. 9 is an elevation view of a shuttle according to the invention.

[0016] Figure 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.

[0017] The bicycle comprises at least two wheels 3, 3' to which a driving force is supplied, via two pedals rotating around a bottom bracket axle Xp [Fig.2] which drives the rear wheel for example by a chain, or any other means of transmission during its use.

[0018] The device 1 also includes a control unit 4 and several sensors 5, 5', 5”, located for example at the level of the pedal assembly, on the frame of the bicycle or at the level of a wheel 3, 3'.

[0019] The device 1 shown herein also includes an energy storage device in the form of a battery 6, a lighting system 7, a pedal assembly 8 with axis Xp [Fig. 2], 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.

[0020] The wheels 3, 3' are equipped with a braking system 31, including disc brakes 32.

[0021] The vehicle 1 comprises a transmission assembly 10 illustrated [Fig.2]. The transmission assembly 10 includes an automatic gear-changing device 20 according to the invention and the electric motor 2 to provide part of the power for the propulsion of the vehicle 1.

[0022] According to a first variant of the invention, the device has 3 speeds.

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

[0024] In the context of the invention, the gear change device 20 illustrated [Fig.2] to [Fig.4] comprises three ratios.

[0025] According to one embodiment of the invention, the gear change device 20 illustrated [Fig.3] and [Fig.4] comprises 3 ratios distributed between a first ratio called ratio n°1 and a higher ratio called ratio n°3.

[0026] According to one embodiment of this first variant, the gear change device 20 comprises a series 60 of three output pinions with reference axis X from Fi to F3, fixed in rotation to a hollow shaft 80 [Fig.8] and a series 50 of three input pinions with reference axis X from FRi to FR3, arranged to rotate freely around the selection shaft 40.

[0027] According to one embodiment of the invention, the selection shaft 40 illustrated [Fig.3] to [Fig.6] houses a shuttle 41 surrounding a worm gear 21 of the speed change device 20.

[0028] The device 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 linkage, between 3 positions from Pi to P3 and engage a selected ratio.

[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 axis of the worm gear 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.

[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 one embodiment of the invention, the gear-changing device 20 comprises a series of three pawls arranged one after the other along the longitudinal axis X2 of the selector shaft 40.

[0033] According to one embodiment of the invention, the gear change device 20 comprises at least a series of three pawls arranged one after the other along the longitudinal axis X2 of the selection shaft 40.

[0034] According to one embodiment of the invention, the gear change device 20 comprises two sets of three pawls arranged one after the other along the longitudinal axis X2 of the selection shaft 40.

[0035] According to one embodiment of the invention, the sets are arranged 180 degrees apart around the selector shaft 40. 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 selector shaft 40. Each pawl 42 is associated with a lifting device, and for example a ball 43, visible [Fig. 5] and [Fig. 6], disposed in a bore 430 of the inner shaft, protruding inside the inner shaft, positioned under each pawl 42 so as to be able to lift it via the shuttle 4L

[0036] More specifically, the shuttle 41 [Fig. 9] comprises a cylindrical body 26 having longitudinal channels 27 extending along its entire length at its periphery and a transverse channel 29 at its center. The shuttle 41 also comprises tabs 25 mounted on the body 26 with thrust means 33. Each tab 25 has a central flat 36 in the center of which is a concave portion designed to cooperate with the lifting device 43 to allow the selection of a ratio. Two fins extend on either side of the central flat 36. longitudinal 34 inclined fitting into one of the longitudinal channels 27 and two inclined transverse fins 35 arranged in the transverse channel 29 when assembled within the body 26.

[0037] Within the framework of the invention, the shuttle includes means for retaining (281, 282) the transverse fins in the transverse channel.

[0038] According to one embodiment of the invention, the means for retaining the transverse fins comprise two lateral edges 281 at their ends. These two edges 281 cooperate with two stops 282 formed in each transverse channel 29. The edges associated with the stops make it possible to retain the tab 35 while allowing it to maintain the elasticity necessary to cooperate with the spring-type thrust means 33.

[0039] According to one embodiment of the invention, the shuttle 41 is made of steel or polymer.

[0040] According to one embodiment of the invention, when the shuttle 41 is made of plastic, it incorporates a dedicated lip to hold a ball bearing in position. This avoids the use of a dedicated circlip.

[0041] Thus, during a change of speed ratio, the worm gear 21 is driven in rotation by the speed change actuator 70 causing the axial movement of the nut 210 of the screw 21 which drives the shuttle 41, the shuttle 41 is positioned under the input pinion Fri 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] According to one embodiment of the invention, to hold the pawls 42 in place in their housing, the gear-changing system includes at least one radial locking system 44 formed in one piece. That is to say, a system 44 that holds the pawls 42 pressed into 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 one piece. This facilitates its assembly and manufacture and reduces costs.

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

[0044] According to one embodiment of the invention, the system 44 comprises three tabs 441 in the case of a three-speed device.

[0045] 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 with respect to the axis Xb of the locking system 44. The locking system 44 in rotation thus forms a comb with flattened and spaced teeth.

[0046] 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, 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 rotational 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 4L

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

[0053] Thus, during the operation of the mobility device, the shuttle 41 allows the selected ratio to be selected, which will engage an input pinion Fri via a ratchet 42 and be blocked in rotation by means of the rotation blocking system 44.

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

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

[0056] During a change of speed ratio, the worm gear 21 is driven in rotation by the gear shift 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 joint thus created, the rotational movement of the worm screw 21 is transformed into the translational movement of the shuttle 4L

[0057] 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.

[0058] According to an embodiment not illustrated, the shuttle 41 is able to take a position called neutral position PO for which no speed ratio is engaged.

[0059] The assembly is arranged in a housing illustrated [Fig. 7] with a first face 100.

[0060] The housing 30 comprises a casing 301 defining a first compartment 302 arranged to house the gears of the speed-changing device 20. The casing 301 also defines several second compartments, distinct from one another. The compartments 303, 304, 305, and 306 are arranged to house, respectively, the electric motor 2, the reduction gear 82, the speed-changing actuator 70, and the control unit 4 of the mobility device. The second compartments are preferably sealed, in particular the one arranged to contain the control unit 4. This first face 100 is closed by a hood or cover type closure system.

[0061] 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 by way of illustration and may be modified without, however, departing from the scope defined by the claims.

Claims

Demands

1. 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 disposed, the shuttle 41 comprising a cylindrical body (26) having, at its periphery, longitudinal channels (27) extending over its entire length and, at the center, a transverse channel (29) into which are inserted two transverse fins (35) of a tab (25) intended to retain a thrust means (33), - a gear-changing 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).each pawl (42) being associated with a lifting device (43) associated with the pushing means (33) allowing the pawl to be lifted via the shuttle (41), and the selected ratio to be engaged via input and output gears, characterized in that the shuttle (41) includes means for retaining (281, 282) the transverse fins (35) in the transverse channel (29).

2. Gear-changing device (20) according to claim 1, wherein the means for retaining (281, 282) the transverse fins (35) comprise two lateral rims (281) at their end.

3. Gear-changing device (20) according to claim 1 or 2, wherein the means for retaining (281, 282) the transverse fins comprise two lateral rims (281) at their end cooperating with two stops (282) formed in each transverse channel (29).

4. Gear-changing device (20) according to any one of claims 1 to 3, wherein the shuttle (41) is made of steel or polymer.

5. Gear-changing device (20) according to any one of claims 1 to 3, wherein the shuttle (41) is made of plastic and incorporates a dedicated lip (283) for holding a ball bearing in position.

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

7. Mobility device according to claim 8, wherein the device (1) is an electrically assisted bicycle.

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