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) and a means (21) 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 to engage a selected gear; the shuttle (41) comprising at least two means (411, 412) for selecting a gear. 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 the function of engaging the selected gear

[0006] the shuttle comprising at least two means for selecting a ratio.

[0007] According to one embodiment of the invention, the shuttle comprises at least two housings for inserting the selection means.

[0008] According to one embodiment of the invention, the shuttle comprises three housings for three selection means arranged at 120 degrees from each other around the shuttle.

[0009] According to one embodiment of the invention, the selection means is formed by a piston device.

[0010] According to one embodiment of the invention, the piston device is a ball piston.

[0011] According to one embodiment of the invention, the selection means is formed by a body inside which a spring and a ball are housed.

[0012] According to one embodiment of the invention, the body is adjusted to the size of the ball to allow it to be held in place.

[0013] According to one embodiment of the invention, the body is made of plastic.

[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 the [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 a schematic representation seen in section of the means of selection according to the invention, - [Fig.7] is an elevation view of part of the device with element of locking of the ratchet according to the invention.

[0017] [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.

[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 includes a control unit 4 as well as several sensors 5, 5', 5”, located for example at the bottom bracket, on the bicycle frame or at the level of a 3, 3' wheel.

[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 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 illustrated [Fig.5] 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 comprises means 412 for selecting a ratio illustrated [Fig.6] formed by a piston device. According to one embodiment of the invention, the piston device 412 is a ball piston.

[0033] According to one embodiment of the invention, the shuttle 41 comprises at least one housing 411 for the insertion of a selection means 412. According to one embodiment of the invention, the shuttle 41 comprises three housings 411 for three selection means 412 arranged at 120 degrees from each other around the shuttle. The selection means 412 are arranged so as to cooperate with pawls 42 to engage a selected gear.

[0034] According to one embodiment of the invention, the selection means 412 are formed by a body 413 inside which are housed a spring 414 and a ball 415. The spring 414 is arranged at the bottom of the housing, and the ball 415 is arranged above the spring so as to protrude from the body 413 along the axis Xb. The ball 415 forms a surface which makes it possible to push a pawl 42 which will in turn engage the selected gear. Thanks to the spring 414, the ball 415 can retract or protrude from the body 413.

[0035] According to one embodiment of the invention, the body 413 is adjusted to the size of the ball 415 to allow it to be held in place. Such a selection means limits the number of parts used for the gear changing device.

[0036] According to one embodiment of the invention, the body 413 is made of plastic.

[0037] The selection means 412 is inserted into the housing 411 formed in the shuttle 4L. More precisely, it is the body 413 of the selection means 412 which is inserted into the housing 411.

[0038] According to one embodiment of the invention, the selection means 412 is inserted by force and / or glued or fixed by any appropriate means.

[0039] 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 the ball is positioned under a ratchet which 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 the shuttle 41.

[0040] According to an embodiment of the invention, illustrated [Fig.7], the gear change device 20 comprises at the level of the selection shaft 40 at least two pawls 42 and for example for a 3-speed engine, comprises three pawls 42, or 7 for a 7-speed engine.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[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 one embodiment of the invention, each pawl 42 is configured to cooperate with the ball of the selection means.

[0047] According to one embodiment of the invention, the pawl is held in place by a radial locking system 44 illustrated [Fig.7]. 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

[0048] 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.

[0049] According to one embodiment of the invention, the locking system 44 comprises a longitudinal flat part 440.

[0050] 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.

[0051] The locking system 44 is arranged on the selection shaft 40 so that each tab 441 is positioned on a ratchet 42.

[0052] According to one embodiment of the invention, each pawl 42 comprises a recess 421 whose shape is complementary to that of the tab 441 so that the tab 441 is housed in the recess 421 of the ratchet, and does not move when the ratchet is locked.

[0053] The rotational locking system 44 bears 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 41. 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.

[0054] 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.

[0055] 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 41 passes.

[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 the lifting of one of the pawls 42, and meshes with the corresponding output pinion Fi.

[0057] If the machine 1 is running in a ratio i, without changing it, the worm screw 21 does not turn.

[0058] 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.

[0059] 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.

[0060] 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 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.

2. Gear changing device (20) according to claim 1, wherein the shuttle (41) comprises at least two housings (411) for the insertion of the selection means (412).

3. A gear changing device (20) according to claim 1 or 2, wherein the shuttle (41) comprises three housings (411) for three selection means (412) arranged at 120 degrees from each other around the shuttle (41).

4. Gear changing device (20) according to one of claims 1 to 3, wherein the selection means (412) are each formed by a piston device.

5. A gear shift device (20) according to claim 4, wherein the piston device is a ball piston (415).

6. Gear change device (20) according to one of claims 1 to 5, in which the selection means (412) are each formed by a body (413) inside which are housed a spring (414) and a ball (415).

7. A gear changing device (20) according to claim 6, wherein the body (413) is adjusted to the size of the ball (415) to allow it to be held in place.

8. A gear changing device (20) according to one of claims 6 to 7, wherein the body (413) is made of plastic.

9. Mobility device (1), in particular assisted mobility device electric, 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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