GEAR SHIFT DEVICE AND ASSOCIATED MOBILITY MACHINE

Abstract

A gear shift device for a mobility machine has a plurality of gears between a first gear referred to as gear No. 1 and a top gear. The gear shift device includes a series of input pinions arranged so as to turn freely around a selection shaft with an axis X.sub.2, said selection shaft accommodating a worm screw and a shuttle. The gear shift device also includes a series of output pinions with an axis X.sub.3 that rotate conjointly with a hollow shaft a gear shift actuator arranged so as to displace the shuttle along the worm screw between a plurality of positions and to engage a selected gear. A mobility machine can include the gear shift device.

Claims

1. Gear shift device for a mobility machine, said device having a plurality of k gears between a first gear referred to as gear No. 1 and a top gear referred to as gear k, said gear shift device having a series of k input pinions arranged so as to turn freely around a selection shaft with an axis X.sub.2, said selection shaft accommodating a worm screw and a shuttle a series of k output pinions with an axis X.sub.3 that rotate conjointly with a hollow shaft a gear shift actuator arranged so as to displace the shuttle along the worm screw between a plurality of k positions and to engage a selected gear.

2. Gear shift device according to claim 1, the shuttle being arranged so as, in each position corresponding to a gear, to engage an input pinion such that it meshes with the output pinion, the input pinion and output pinion being associated with said gear.

3. Gear shift device according to claim 1, the shuttle being arranged so as to accommodate at least one return member.

4. Gear shift device according to claim 1, such that the shuttle surrounds the worm screw.

5. Gear shift device according to claim 1, having a pivot connection.

6. Gear shift device according to claim 1, such that the gear shift actuator has a motor, and a reduction gear or an epicyclic gear train.

7. Gear shift device according to claim 1, such that the gear shift actuator is arranged so as to displace the shuttle between the predefined positions following a gear selection request from a rider of the mobility machine and/or from a control unit of the mobility machine.

8. Gear shift device according to claim 1, such that the shuttle can adopt a position referred to as the neutral position in which no gear ratio is engaged.

9. Gear shift device according to claim 1, having a rail along which the shuttle is displaced, said rail being located in particular in the selection shaft.

10. Gear shift device according to claim 1, having an epicyclic gear train with an inner ring and an outer ring.

11. Mobility machine, in particular an electrically assisted mobility machine, having a gear shift device according to claim 1.

12. Gear shift device according to claim 2, the shuttle being arranged so as to accommodate at least one return member.

13. Gear shift device according to claim 2, such that the shuttle surrounds the worm screw.

14. Gear shift device according to claim 2, having a pivot connection.

15. Gear shift device according to claim 2, such that the gear shift actuator has a motor, and a reduction gear or an epicyclic gear train.

16. Gear shift device according to claim 2, such that the gear shift actuator is arranged so as to displace the shuttle between the predefined positions following a gear selection request from a rider of the mobility machine and/or from a control unit of the mobility machine.

17. Gear shift device according to claim 2, such that the shuttle can adopt a position referred to as the neutral position in which no gear ratio is engaged.

18. Gear shift device according to claim 2, having a rail along which the shuttle is displaced, said rail being located in particular in the selection shaft.

19. Gear shift device according to claim 2, having an epicyclic gear train with an inner ring and an outer ring.

20. Mobility machine, in particular an electrically assisted mobility machine, having a gear shift device according to claim 2.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0045] Other features, details and advantages of the invention will become more clearly apparent upon reading the description given below by way of indication, with reference to the drawings, in which:

[0046] FIG. 1 is a view of a mobility machine according to one of the aspects of the invention,

[0047] FIG. 2 illustrates the transmission assembly of the mobility machine of FIG. 1,

[0048] FIG. 3a, FIG. 3b and FIG. 3c show various sectional views of a gear shift device according to a first embodiment of the invention,

[0049] FIG. 4 illustrates a casing that accommodates a gear shift device according to the invention, FIG. 5 and FIG. 6 illustrate a gear shift device according to a second embodiment of the invention in section,

[0050] FIG. 7a to FIG. 7g schematically show different variants of a gear shift actuator according to the first embodiment of the invention, and

[0051] FIG. 8a to FIG. 8g schematically show different variants of a gear shift actuator according to the second embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0052] FIG. 1 illustrates a mobility machine 900 according to one of the aspects of the invention. Here, the machine 900 is an electrically assisted bicycle having an electric motor 300 with an axis of rotation X.sub.m. Said electric motor is arranged so as to provide some of the propulsion of said machine.

[0053] When travelling without electrical assistance, the motive force is supplied by the cyclist and is transmitted to the wheels 950 via two pedals turning about an axis Xp of a crankset that drives the rear wheel via a chain.

[0054] As shown in FIG. 1, the machine 900 has a control unit 800 and multiple sensors 80, located in particular at the crankset, on the bicycle frame or at a wheel.

[0055] Here, the machine 900 also has an energy storage device in the form of a battery 910, a lighting system 920, a crankset 940 with an axis Xp, a locating and/or navigation system 980, and a human/machine interface system 990 having in particular a touch screen that can display information for and/or take into account the requests of said user. The human/machine interface system 990 is in particular connected to the locating system 980 and acts as a navigation interface. The invention is not limited to a particular human/machine interface system, and may have any system that is known to a person skilled in the art.

[0056] The wheels 950 are provided with a braking system 960, having in particular disk brakes 965.

[0057] The machine 900 has a transmission assembly 700, illustrated in FIG. 2. The transmission assembly 700 has a gear shift device 100 according to the invention and an electric motor 300 with an axis of rotation Xm for supplying some of the power for propelling the machine 900.

[0058] The transmission assembly 700 is at least partially accommodated in a casing 600 (illustrated in FIG. 4), positioned here at the crankset 940, the axis of which coincides with the output axis X.sub.3 of the gear shift device 100.

[0059] The gear shift is automatic and electric.

[0060] The gear shift device 100 illustrated in FIGS. 3a et seq. has a plurality of 7 gears between a first gear referred to as gear No. 1 and a top gear referred to as gear 7.

[0061] It has a series of 7 output pinions 30 with an axis X.sub.3, of reference F.sub.1 to F.sub.7, that rotate conjointly with a hollow shaft, and a series of 7 input pinions 20, of reference Fr.sub.1 to Fr.sub.7, that are arranged so as to turn freely around a selection shaft 200. The latter accommodates a shuttle 155 surrounding a worm screw 132 of the gear shift device 100. A gear shift actuator 150 is arranged so as to displace the shuttle 155 along the worm screw 132 between 7 positions from P.sub.1 to P.sub.7 and to engage a selected gear.

[0062] The device is compact, the selection shaft 200 is hollow.

[0063] The gear shift device 150 includes electric means for moving the shuttle, in the form of a reduction gearset. This reduction gearset has a motor 140 and a reduction gear 130. The gear shift actuator 150 also has mechanical means for bringing about a translational movement of the shuttle 155, in particular means for transforming a rotational movement into a translational movement.

[0064] Here, the reduction gearset assembly has a pinion 135 on the axis of the worm screw 132, an intermediate pinion 135 and a pinion 135 on the axis Xm of the motor 140. The teeth of the pinion 135 may be straight, as illustrated, or helical, in a variant which is not illustrated.

[0065] As shown in FIG. 3a, the gears are shifted by a sliding shuttle 155 underneath the free pinions 30 of the gearbox.

[0066] The gear shift actuator 150 axially displaces the shuttle along a worm screw 132 via a helical kinematic connection.

[0067] The shuttle 155 therefore stops underneath the input pinion Fr, that corresponds to the selected gear i. A spring/ball system as described in the French patent application FR2975367 A1 (illustrated here in more detail in FIG. 5) prevents the rotation of said input pinion Fri. Once it is triggered, the input pinion Fri meshes with and transmits forces to the output pinion Fi, and thus to the chain sprocket linked to the bicycle wheel.

[0068] The rotational guidance of the worm screw 132 is ensured using bearings at each of its ends, for example. FIG. 3a illustrates in particular a needle bushing on the side of the pinions 135 of the reduction gear 130 and a ball bearing at the other end of the worm screw 132.

[0069] FIGS. 3b and 3c show detail views of the gear shift device of FIG. 3a.

[0070] Whereas the shuttle 155 is illustrated in FIG. 3a in the position P.sub.7 corresponding to a gear No. 7, here the top gear, and engages the input pinion Fr.sub.7 such that it meshes with the output pinion F.sub.7, in FIG. 3b the shuttle 155 is in the position P.sub.1 corresponding to a gear No. 1 and engages the input pinion Fr.sub.1 by virtue of a ball/spring device. The shuttle houses a return member 152 that cooperates with a ball 151 of the selection shaft 200.

[0071] The shuttle 155 is moreover connected to a rail 134 by a nut 138.

[0072] If the machine 900 rolls in a gear i, without it being shifted, the worm screw 132 does not turn. As shown in FIG. 3c, the shuttle 155 surrounding the nut 138 can turn by virtue of the bearing 136, retained by a clip 137 here.

[0073] In the event of a gear-ratio shift, the worm screw 132 is rotated by the gear shift actuator 150. The worm screw 132 is rotated by the gear shift actuator 150, this causing the axial movement of the nut 138 which drives the shuttle 155 and thus changes the gear. The pivot connection thus implemented transforms the rotational movement of the worm screw 132 into the translational movement of the shuttle 155. A stop 133 limits the displacement of the shuttle 155 at each end. The stops 133 are for example hollow, as illustrated, and accommodate bearings 136 that serve to support and guide the worm screw 132.

[0074] In a variant which is not shown, the shuttle 155 may adopt a position referred to as the neutral position P0 in which no gear ratio is engaged.

[0075] In the example of the gear shift device described above, the gear shift actuator 150 has straight pinions. In the context of the invention, the reduction gearset may have helical pinions.

[0076] FIG. 4 illustrates the casing 600 for the mobility machine 900 of FIG. 1 in more detail.

[0077] The casing 600 has a crankcase 660 that delimits a first housing 610 arranged so as to accommodate the gearings of the gear shift device 100. The crankcase 660 also delimits multiple second housings that are separate from one another. The housings 640, 630, 615 and 680 are arranged so as to accommodate the electric motor 400, the reduction gear 300, the gear shift actuator 150 and the control unit 800 of the mobility machine, respectively. The second housings are preferably sealed, in particular that one which is arranged so as to contain the control unit 800.

[0078] The crankcase 660 accommodating the gear shift device 100 is closed by two lateral flanges 667. The casing 600 is illustrated empty and with just one flange 667 in FIG. 4 in order to make the various first and second housings more visible. The first housing 610 has two facing holes in the lateral flanges 667 for receiving the axle of crankset spindle of the mobility machine 900.

[0079] FIGS. 5 and 6 relate to the second embodiment. The gear shift device 100 has an epicyclic gear train 130 having an inner ring 30 int that is integral with the selection shaft 200 and an outer ring 30 ext that is integral with the worm screw 132. The inner ring 30 int and the outer ring 30 ext are linked by three satellite pinions 135.

[0080] In the steady state of rolling, the worm screw 132, the selection shaft 200 and the shuttle 155 turn at the same speed. In order to shift gears, the reduction gearset 140 temporarily turns the outer ring through a determined angle that depends on the necessary displacement of the shuttle 155 between the positions that respectively correspond to the initial gear and to the desired gear. Following the angular deflection thus created between the inner ring 30 int and the outer ring 30 ext, the ratio between the rotation of each ring is temporarily no longer equal to one. The shuttle 155 is thus driven in a translational movement until it reaches a new position corresponding to the new gear that is selected.

[0081] The first embodiment with a rail and nut is not limited to one type of reduction gearset having pinions with parallel axes, as illustrated in FIG. 3a. The axes of the pinions of the reduction gearset may be perpendicular.

[0082] Whereas in the illustrated variants of the first embodiment, in particular the example illustrated in FIG. 3a, the reduction gearset has multiple pinions 135, FIG. 7a corresponds to an example in which the reduction gearset 130 is limited to a single pinion.

[0083] FIG. 7b illustrates a variant in which the gear shift actuator 150 has a conical gearing 130.sub.b.

[0084] FIG. 7c illustrates a variant in which the gear shift actuator 150 has a straight-cut or helical gearing 130.sub.c with one or more stages.

[0085] FIG. 7d illustrates a variant in which the gear shift actuator 150 has a continuously variable straight-cut or helical gearing 130.sub.d.

[0086] FIG. 7e illustrates a worm screw 130.sub.e of a variant of the gear shift actuator 150.

[0087] FIGS. 7f and 7g show variants having a gear shift actuator 150 with a belt 130.sub.f and a chain 130.sub.g, respectively.

[0088] Similarly, FIGS. 8a to 8g schematically show different variants of a gear shift actuator according to the second embodiment of the invention.

[0089] FIG. 8a corresponds to the example illustrated in FIG. 5a with the epicyclic gear train 130.

[0090] FIG. 8b illustrates a variant in which the gear shift actuator 150.sub.b has an epicyclic gear train 130 and a conical gearing.

[0091] FIG. 8c illustrates a variant in which the gear shift actuator 150.sub.c has an epicyclic gear train 130 and a straight-cut or helical gearing with one or more stages. FIG. 8d illustrates a variant in which the gear shift actuator 150.sub.d has an epicyclic gear train 130 and a continuously variable straight-cut or helical gearing. FIG. 8e illustrates a variant in which the gear shift actuator 150.sub.e has an epicyclic gear train 130 and a worm. FIGS. 8f and 8g show variants having a gear shift actuator 150.sub.f with an epicyclic gear train 130 and a belt, and a gear shift actuator 150.sub.g with an epicyclic gear train 130 and a chain, respectively.