Gear-changing device and associated mobility device.

Abstract

The invention relates to a gear-changing device for a mobility device comprising: a selector shaft in which a shuttle (41, 431, 413, Xn) and a means for moving the shuttle (41) are disposed; a gear-changing actuator arranged to move the shuttle (41) along the means of movement between at least two positions and engage a selected gear; at least two pawls disposed on the selector shaft ensuring the function of engaging the selected gear; characterized in that the shuttle comprises at least two means (412) for selecting a gear, the selection means being formed by at least two elastic blades and a ring supporting the blades. 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 tree in which a shuttle and a means of moving the shuttle are arranged, - a gearshift actuator arranged to move the shuttle along the moving means between at least two positions, and engage a selected gear, - at least two pawls arranged at the level of the selection shaft ensuring the function of engaging the selected gear

[0006] the shuttle comprising at least two means for selecting a ratio, the selection means being formed by at least two elastic blades and a ring supporting the blades.

[0007] According to one embodiment of the invention, the ring is configured to be inserted on one end of the shuttle and is extended, along the longitudinal axis Xn of the shuttle, by at least two elastic blades.

[0008] According to one embodiment of the invention, the ring comprises three elastic blades arranged at 120 degrees from each other around the shuttle.

[0009] According to one embodiment of the invention, each elastic blade has a free end allowing the elastic function of the blade to occur.

[0010] According to one embodiment of the invention, the blade comprises three flat zones (arranged one after the other, a central zone and a second and third zone arranged on either side of the central zone, each forming an angle of less than 120 degrees with the central zone.

[0011] According to one embodiment of the invention, the end of the blade opposite the free end is connected to the ring.

[0012] According to one embodiment of the invention, the ring is held in place by an additional ring.

[0013] According to one embodiment of the invention, the shuttle comprises anti-rotation means.

[0014] The invention also relates to a mobility device, in particular an electrically assisted mobility device, comprising a gear change device according to the invention.

[0015] According to one embodiment of the invention, the machine is an electrically assisted bicycle.

[0016] 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 [Fig.3b] illustrate 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 an elevation view of the shuttle according to the invention, - [Fig.6] is an elevational representation of the selection means according to the invention, - [Fig.7] is a sectional view of the shuttle according to the invention, - [Fig.8] is a sectional view of part of the gear changing device speed according to the invention, - [Fig.9] is an elevation view of a part of the device with ratchet locking element according to the invention.

[0017] [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.

[0018] 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 [Fig.2] which drives the rear wheel for example by a chain, or any other means of transmission during its use.

[0019] 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'.

[0020] 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 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.

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

[0022] 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.

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

[0024] According to one embodiment of the invention, the gear change device 20 illustrated [Fig.3a] and [Fig.3b]] comprises at least 2 ratios, and for example 3 or 7 ratios between a first ratio called ratio no. 1 and a higher ratio called ratio no. 3 or no. 7.

[0025] 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 F3 or F7, integral in rotation with a hollow shaft 80 and a series of seven input pinions 50, of reference Fri to Fr3 or Fr7 arranged to rotate freely around the selection shaft 40.

[0026] 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.

[0027] 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 3 or 7 positions from Pi to P3 or P7 and engage a selected gear.

[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] In the context of the invention, the shuttle 41 illustrated [Fig.5] comprises means 412 for selecting a ratio formed by at least two elastic blades 415 and a ring 416 supporting the blades 415 illustrated [Fig.6].

[0033] According to one embodiment of the invention, the ring 416 is configured to be inserted on one end of the shuttle 4L. The ring is extended, along the longitudinal axis Xn of the shuttle 41, by at least two elastic blades 415, and for example three elastic blades 415 illustrated [Fig.5] and [Fig.6]. The axis Xn of the shuttle 41 being parallel to the axis X2 of the selection shaft 40.

[0034] According to one embodiment of the invention, the ring 416 comprises three elastic blades 415 arranged at 120 degrees from each other around the shuttle 4L

[0035] According to an embodiment of the invention illustrated [Fig.7], each elastic blade 415 has a free end 417 allowing the elastic function of the blade to occur. Indeed, the fact that one end is free allows the blade to flatten and lift. According to an embodiment of the invention, this free end 417 is curved to promote the bending of the blade 415.

[0036] According to one embodiment of the invention, the blade comprises three flat zones 414, 418, 419 arranged one after the other. A central zone 414 and a second and third zones 418, 419 arranged on either side of the central zone 414 each forming with the central zone an angle of less than 120 degrees. All of these three zones allow the elasticity of the blade 415. The second 418 and third 419 zones are oriented towards the surface of shuttle 41.

[0037] According to one embodiment of the invention, the end of the blade 415 opposite the free end 417 is connected to the ring 416. The connection is made either because the blade 415 forms a single piece with the ring 416, or because it is fixed by any means compatible with its use.

[0038] According to one embodiment of the invention, the central zone 414 cooperates with the ball enabling the pawl to be engaged. This central zone 414 is a pressure zone enabling the pawl 42 to be pushed back and the selected gear to be engaged.

[0039] According to one embodiment of the invention, the ring is held in place by an additional ring 413.

[0040] According to one embodiment of the invention, the additional ring 413 is not radially flat, but has a V-shape, allowing in-depth support on certain areas of the ring 416, thus allowing the ring 416 to be correctly positioned. This makes it possible to eliminate a step in the chain of dimensions.

[0041] This additional ring 413 makes it possible to prevent the selection means 412 from having play, and allows them to be held in place on the shuttle 41.

[0042] Such a selection means limits the number of parts used for the gear changing device.

[0043] According to one embodiment of the invention, the blade 412 is made of metal, metal alloy and for example steel.

[0044] According to one embodiment of the invention, the shuttle 41 is made of polymer.

[0045] In the context of the invention, the shuttle 41 comprises anti-rotation means 431. These anti-rotation means are formed by at least one ball 431 inserted into the surface of the shuttle 41. According to one embodiment of the invention, the shuttle 41 comprises three balls 431 interposed with the three blades 415 of the selection means 412.

[0046] The balls 431 are overmolded, glued or fixed by any other means compatible with their use.

[0047] These anti-rotation means prevent the shuttle from rotating around the worm screw.

[0048] According to one embodiment of the invention, the rotation means have any shape compatible with their function.

[0049] Thus, during a gear change, the worm screw 21 is rotated by the gear change actuator 70 causing the axial movement of the nut 210 of the screw 21 which drives the shuttle 41, the selection means via a ball is positioned under a pawl which allows the gear change. Thanks to the pivot connection thus produced, the rotational movement of the worm screw 21 is transformed into a translational movement of the shuttle 4L

[0050] According to one embodiment of the invention, illustrated [Fig.8], the gear change device 20 comprises at the level of the selection shaft 40 at least two 42 pawls and for example for a 1 to 3 speed engine, has three 42 pawls, or 7 for a 7 speed engine.

[0051] According to one embodiment of the invention, the gear change device 20 comprises a series of three or seven pawls arranged one after the other along the longitudinal axis X2 of the selection shaft 40.

[0052] According to one embodiment of the invention, the gear changing device 20 comprises at least one series of at least three pawls arranged one after the other along the longitudinal axis X2 of the selection shaft 40.

[0053] According to one embodiment of the invention, the gear changing device 20 comprises two series of at least three 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.

[0054] According to one embodiment of the invention, the gear changing device 20 comprises three series of at least three 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.

[0055] The pawls 42 have a shape configured to cooperate with the input gears Fri. The pawls 42 are inserted into recesses 420 formed on the selection shaft 40 by one end 422. This end is fully inserted into the housing so as to be pressed against the upper face 423 of the housing 420. Each pawl 42 is associated with a lifting device, and for example a ball 43, visible [Fig.8] arranged in a bore of the selection shaft 40, protruding inside the shaft 40, placed under each pawl 42 so as to be able to lift it via the shuttle 4L

[0056] When the speed is selected, the shuttle 41 is positioned under the input pinion Fr, 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.

[0057] According to one embodiment of the invention, the pawl is held in place by a radial locking system 44 illustrated [Fig.9]. 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

[0058] 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.

[0059] According to one embodiment of the invention, the locking system 44 comprises a longitudinal flat part 440.

[0060] 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.

[0061] The locking system 44 is arranged on the selection shaft 40 so that each tab 441 is positioned on a ratchet 42.

[0062] According to one embodiment of the invention, each pawl 42 comprises a recess 421 whose shape is complementary to that of the tongue 441 so that the tongue 441 is housed in the recess 421 of the pawl, and does not move when the pawl is locked.

[0063] The rotational locking system 44 rests 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 of the locking system 44 is exerted towards the inside of the selection shaft 40. According to one embodiment of the invention, the locking system is arranged longitudinally along the axis X2 in one direction or the other.

[0064] 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.

[0065] 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 when the shuttle 4L passes.

[0066] 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.

[0067] If the machine 1 is running in a ratio i, without changing it, the worm screw 21 does not turn.

[0068] 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.

[0069] 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.

[0070] 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 means (21) for moving the shuttle (41) are arranged, - a gear change actuator (70) arranged to move the shuttle (41) along the means of movement (21) between at least two positions, and engage a selected gear, characterized in that the shuttle comprises at least two means (412) for selecting a gear, the selection means being formed by at least two elastic blades (415) and a ring (416) supporting the blades (415).

2. Gear changing device (20) according to claim 1, wherein the ring (416) is configured to be inserted on one end of the shuttle (41) and extends, along the longitudinal axis Xn of the shuttle (41), by at least two elastic blades (415).

3. A gear changing device (20) according to claim 1 or 2, wherein the ring (416) comprises three elastic blades (415) arranged at 120 degrees to each other around the shuttle (41).

4. A gear changing device (20) according to one of claims 1 to 3, wherein each elastic blade (415) has a free end (417) allowing the elastic function of the blade to occur.

5. Gear changing device (20) according to one of claims 1 to 4, in which the blade comprises three flat zones (414, 418, 419) arranged one after the other, a central zone (414) and a second and third zones (418, 419) arranged on either side of the central zone (414) each forming with the central zone an angle of less than 120 degrees.

6. A gear changing device (20) according to claim 5, wherein the end of the blade (415) opposite the free end (417) is connected to the ring (416).

7. Gear changing device (20) according to one of claims 1 to 6, wherein the ring is held in place by an additional ring (413).

8. Gear changing device (20) according to one of claims 1 to 7, wherein the shuttle (41) comprises anti-rotation means (431).

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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