WO2018024551A1

WO2018024551A1 - Cycle equipped with an electrical assistance module, and electrical assistance module for such a cycle

Info

Publication number: WO2018024551A1
Application number: PCT/EP2017/068806
Authority: WO
Inventors: Christophe DJOLOLIAN; Hervé Lenon; Solène MARTINEZ; Cyprien TEILLOU
Original assignee: Ntn-Snr Roulements
Priority date: 2016-07-30
Filing date: 2017-07-25
Publication date: 2018-02-08
Also published as: FR3054521A1; FR3054521B1

Abstract

A cycle has at least one chain (28) of given pitch, a crankset (18) having at least two crankset plates (20, 22, 24) that are provided with teeth (26) at the pitch of the chain (28) and are able to mesh with the chain (28), turning about a crankset axis (100). The cycle is equipped with an electrical assistance module (30) having an electric motor (32), the drive shaft (34) of which, which is parallel to the crankset axis (100), drives an output member (40) turning about a second axis of rotation (120) parallel to the first axis of rotation (110) by way of a speed reduction mechanism (36). The output member (40) meshes with the teeth (26) of a first of the crankset plates (20, 22, 24) and the chain (28) meshes with the teeth (26) of a second of the crankset plates (20, 22, 24).

Description

CYCLE EQUIPPED WITH AN ELECTRICAL ASSISTANCE MODULE, AND SERVICE MODULE

ELECTRICAL FOR SUCH A CYCLE

TECHNICAL FIELD OF THE INVENTION

The invention relates to a cycle equipped with a motorized electric assistance module, preferably removable, and a power assisted motorized module for such a cycle.

STATE OF THE PRIOR ART

It has been proposed in document FR3013311 to equip a motorization kit with a pre-existing bicycle comprising a double-deck crankset. The motorization kit comprises a disengageable motor and an alternator rotating about a common axis perpendicular to the pedal, a bevel gear between the alternator shaft and a small pinion which drives the small plate of the pedal via an auxiliary chain. In an engaged position, the motor drives the alternator shaft and, through the bevel gear, the small pinion and the auxiliary chain, the small plate of the pedal, whose large plate drives the main chain of the cycle transmitting the assist torque to the rear wheel of the cycle. The transmission formed by the bevel gear and the auxiliary chain is poor in terms of transmission ratio and friction. In particular, the transmission ratio between the engine and the crankset is relatively low, which imposes a high torque and low speed engine.

In WO15044695 has been proposed a bicycle motorization module, which can if necessary be mounted either on a specific bicycle designed from the beginning for electrical assistance, or as a kit on a standard bicycle with a pre-existing pedals double tray. The motorization module comprises an electric motor whose motor shaft rotates about a first axis of revolution parallel to the bottom bracket axis, an output member rotating about a second axis of revolution parallel to the first axis of revolution and remote from the first axis of revolution and the crank axle, and a speed reduction mechanism between the motor shaft and the output member. The output member is a pinion which drives an auxiliary chain meshing with the small plate of the pedal, whose big plateau drives the main chain. Because of the auxiliary chain, the assembly kit is quite complex. In the case of an original factory assembly, it is also envisaged to replace the last reduction stage, previously consisting of the pinion, the auxiliary chain and the small plate of the pedal, by a specific gear or helical straight, or synchronous driven pulleys connected by a synchronous chain. But these alternatives are unthinkable for a kit to ride on a standard bicycle.

In the document CH707430 is described a cycle comprising at least one given chain of pitch, a crankset rotating about a crank axis, the crankset having at least two bottom plates with teeth at the foot of the chain and suitable to mesh with the chain, an electric assistance module comprising an electric motor comprising a motor shaft rotating about a first axis of revolution perpendicular to the bottom bracket axis, an output member rotating about a second axis of revolution parallel to the first axis of revolution and remote from the first axis of revolution and the bottom bracket axis, and a gear mechanism between the motor shaft and the output member. The output member meshes with the teeth of a first of the bottom plates and the chain meshes with the teeth of a second bottom plates. This architecture requires a high torque motor, because the gearbox mechanism allows a low gear ratio, and has a low efficiency.

STATEMENT OF THE INVENTION

The invention aims to overcome the disadvantages of the state of the art and to provide an electrical assistance cycle architecture that allows a simple mounting of the support module, and is optionally compatible with a kit use on a standard bicycle.

To do this is proposed, according to a first aspect of the invention, a cycle comprising at least a given chain of steps, a crankset rotating about a crank axis, the crankset having at least two bottom plates provided of teeth at the pitch of the chain and adapted to mesh with the chain, an electric assistance module comprising an electric motor comprising a motor shaft rotating about a first axis of revolution parallel to the bottom bracket axis, a body of output rotating about a second axis of revolution parallel to the first axis of revolution and remote from the first axis of revolution and the bottom bracket axis, and a speed reduction mechanism between the motor shaft and the output member. The output member meshes with the teeth of a first of the bottom plates and the chain meshes with the teeth of a second bottom plates. Direct meshing between the output member of the power assistance module facilitates mounting and increases the reliability of the kinematic link. The gear reduction mechanism has a ratio between the speed of revolution of the drive shaft and the revolution speed of the output member which, in absolute value, is greater than 20. In practice, the pedal has several trays of diameters growing from a small plateau to a large plateau. The output member may mesh, in particular with the large plate or with the small plate, or even one of the intermediate plates. The chain can mesh with any of the other trays. The meshing of the output member with the small or large plate offers the additional advantage, in the case of a pedal with more than two trays, to allow the cyclist to use the derailleur to change the plateau between the trays not occupied by the output member.

Preferably, the first axis of revolution is further from the axis of the pedalboard than the second axis of revolution. According to one embodiment, the cycle further comprises a frame, comprising a seat tube, a diagonal tube, and a bottom bracket tube disposed at a lower end of the seat tube and the down tube. The crankset has a bottom bracket bearing received in the bottom bracket tube. The power assist module is preferably attached to the down tube. Preferably, the electric assistance module is fixed under the down tube in a use position of the cycle.

According to one embodiment, the output member comprises meshing portions, equidistributed at a distance from each other at the pitch of the chain around the second axis of revolution, each of the meshing portions having a face of convex meshing protruding radially outwards with, in a plane perpendicular to the second axis of revolution, a radius of curvature whose length varies by less than 20% over an angular sector of at least 120 °, and a center of curvature located at a distance from the second axis of revolution greater than radius of curvature. The radius of curvature of the meshing faces can be constant. Preferably, the radius of curvature is constant over an angular sector of at least 120 °. The convex meshing face of each of the drive portions preferably coincides with a cylindrical sector or a cylinder, of axis parallel to the second axis of revolution.

According to one embodiment, the output member comprises a flange disposed perpendicular to the second axis of revolution, carrying bars extending parallel to the second axis of revolution, equidistant around the second axis of revolution at a circular periphery of the flange, each of the bars forming or carrying one of the meshing portions. The output member then constitutes a squirrel cage, open if the plate is single, or closed if it comprises a second plate parallel to the first plate, the bars extending from one plate to the other.

According to one embodiment, the pitch of the chain is 12.6, 12.7 or 12.8 mm.

According to one embodiment, the electrical assistance module comprises a housing housing of the motor and the gearbox, provided with fixing means to a frame of the cycle. Preferably, the fixing means comprise at least one support member fixed on the frame of the cycle and at least one removable locking member integral with the housing, adapted to lock the housing in at least one position with respect to the support member. , and preferably to lock the housing in a plurality of positions relative to the support member. The support member preferably defines a plurality of locking positions of the locking member, located on the same rectilinear or circular path parallel to a plane perpendicular to the first axis of revolution. Where appropriate, the locking member comprises a device for adjusting the position of the housing relative to the support member parallel to the first axis of revolution. According to one embodiment, the speed reduction mechanism has a ratio between the speed of revolution of the motor shaft and the revolution speed of the output member which, in absolute value, is greater than 30.

The speed reduction mechanism can include in particular one or more of the following elements: a deformation wave gear; an oscillating eccentric gear.

According to another aspect of the invention, it relates to an electrical assistance module for a cycle as described above. BRIEF DESCRIPTION OF THE FIGURES

Other features and advantages of the invention will emerge on reading the description which follows, with reference to the appended figures, which illustrate: FIG. 1 is an isometric view of an electric assistance bicycle, showing in particular the implantation of an electrical assistance module from a right side of the bicycle; Figure 2 is an isometric view of the left side of the power assisted bicycle of Figure 1; FIG. 3, an isometric view of the bicycle of FIG. 1, the electric assistance module being presented without a cover; FIG. 4, an isometric view of the bicycle of FIG. 1 at another angle making it possible to visualize the connection between the electric assistance module and a crankset of the bicycle; Figure 5 is a schematic view of the electric assist module of the bicycle of Figure 1; - Figure 6, a detail of an alternative embodiment of an output member of the electric assistance module of the bicycle of Figure 1; Figure 7 is an isometric view of another embodiment of an output member of the electric assist module of the bicycle of Figure 1; Figure 8 is an isometric view of another embodiment of an output member of the power assist module of the bicycle of Figure 1; FIG. 9 is an exploded view of an electric assistance module according to FIG. 5 equipped with an eccentric speed reducer; FIG. 10 is a sectional view of the electrical assistance module of FIG. 9.

For clarity, identical or similar elements are identified by identical reference signs throughout the figures.

DETAILED DESCRIPTION OF EMBODIMENTS

As illustrated in Figures 1 to 4, the frame 10 of a bicycle 11 trade includes a seat tube 12, a diagonal tube 14, and a bottom bracket tube 16 disposed at a lower end of the tube. saddle 12 and the down tube 14. In the bottom bracket tube 16 is housed a crank bearing (not shown) which provides the rotational guidance of a crankset 18 about an axis of revolution, said bottom bracket 100 The pedal 18 has three trays, namely a large plate 20, an intermediate plate 22 and a small plate 24, which are provided with teeth 26 which enable them to mesh with a chain 28 of standard pitch, for example the pitch 12.7 mm, illustrated in Figures 2 and 4. In Figure 2, the chain 28 meshes with the intermediate plate 22.

The bicycle of Figure 1 has been equipped with an electric assistance module 30, fixed to the diagonal tube 14 so as to be under the diagonal tube 14 in a position of use of the bicycle. The electric assistance module 30, illustrated in FIG. 5, comprises an electric motor 32 whose driving shaft 34 rotates about a first axis of revolution 110 parallel to the bottom bracket axis 100, located at a distance from the pedal shaft 100. The motor 32 drives a mechanism speed reducer 36, which itself drives, via a freewheel 38, an output member 40 of the electric assistance module 30. The output member 40 rotates about a second axis of revolution 120 parallel to the first axis of revolution 110 and remote from the first axis of revolution 110 and the bottom bracket 100, the first axis of revolution 110 being further from the axis of the pedal 100 than the second axis of revolution 120. motor 32 and the gearbox 36 are housed in a housing 42 partially closed by a cover 43 and fixed to the frame 10 by removable fixing means 44 comprising a support member consisting of a slide 44A fixed to the down tube 14 and a locking member constituted by a self-locking slide 44B secured to the housing 42.

The speed reduction mechanism 36, which has not been shown in detail here, may be of any suitable type, and may include in particular a deformation wave gear, an oscillating eccentric gear and / or one or more gear trains, so as to have a ratio between the speed of revolution of the drive shaft 34 and the revolution speed of the output member 40 which, in absolute value, is greater than 20, preferably greater than 30 .

The output member 40 comprises a flange 46 disposed perpendicularly to the second axis of revolution 120, carrying cylindrical bars 48 extending parallel to the second axis of revolution 120, equidistributed around the second axis of revolution 120 at a circular periphery flange 46, and the pitch of the chain, so as to mesh with the teeth 26 of the small plate 24 of the pedal.

Thus, when the electric motor 32 is energized, it drives the output member 40 which itself applies to the pedal 18 a torque of assistance which is added to the torque applied by the cyclist on the pedals 50 and can drive the chain 28 and the bicycle.

The bars 48 may be directly in contact with the teeth 26 of the small plate 24 of the pedal 18. Alternatively, and as shown in Figure 6, it can be provided that each bar 48 is provided with a ring 52 attached by example brass, mounted with a slight clearance ensuring a freedom of rotation around the axis 130 of the bar.

One can also provide a second flange 54 parallel to the first flange 46 to stiffen the output member 40, as shown in Figure 7. Finally, there may be an output member 40 constituting a gear wheel 56 having teeth 58 shaped so as to mesh with one of the plates 20, 22, 24 of the crank 18, as illustrated in FIG. 8.

In all the configurations illustrated in the figures, the output member comprises meshing portions, constituted either by the teeth 58, or by the bars 48, or by the rings 52, these meshing portions being equal parts spaced from each other at the pitch of the chain 28 around the second axis of revolution 120, each of the meshing portions 48, 52, 58 having a convex meshing face 60 projecting radially outwards relative to the second axis of revolution 120 with, in a plane perpendicular to the second axis of revolution, a constant radius of curvature and a center of curvature located at a distance from the second axis of revolution greater than the radius of curvature. More specifically, the meshing faces of the teeth 58 coincide with cylinder portions over an angular sector of at least 120 ° measured at the center of curvature, whereas the meshing faces of the bars 48 and rings 52 are entirely cylindrical. .

The mounting of the electric assistance module 30 can be performed very simply on the bicycle not yet equipped: after fixing the slide 44A on the diagonal tube 14, is slid the slide 44B to get a positioning the output member 40 which meshes with the small plate 24 of the pedal 18, then the slide 44B is allowed to lock in the slide 44A. This method of attachment makes it possible to assemble and dismount at will the electric assistance module 30 and to consider, for example, a systematic dismantling each time the user leaves his bicycle in a public place. It also allows decoupling the electric assistance module by fixing the latter in the upper part of the slide 44A. These fixing means 44 also make it possible to continuously varying the positioning of the housing relative to the slide along a rectilinear path parallel to the diagonal tube 14 and perpendicular to the first axis of revolution 110, so as to adjust the positioning to obtain optimum meshing. Naturally, the invention is not limited to the described embodiments. The positioning and attachment mode of the power assist module 30 may vary. The control of the electric motor 32 can be of any suitable type, controlled for example by torque and / or speed or chain tension measurements. The fastening means 44 may be equipped with means for adjusting the position of the housing 42 parallel to the first axis of revolution 110, which may in particular be integrated with the locking member 44B. It is also possible that the sliding between the slide 44A and the slide 44B, is used for a coarse positioning of the housing 42, parallel to the axis of the slide 44A, a finer adjustment in the axis of the slide or more generally in a plane perpendicular to the first axis of revolution 110 being formed by integral adjustment means to the slider 44B.

Instead of the slide 44A and the slider 44B, there can be provided a pivoting device for positioning the housing on a circular path in a plane perpendicular to the first axis of revolution 110.

The assistance module is usable on any type of cycle, having at least 2 trays.

FIGS. 9 to 10 illustrate in greater detail one embodiment of an oscillating eccentric gear reduction mechanism 36 integrated in the electrical assistance module 30 of FIG. 5. The eccentric speed reduction mechanism oscillating elements 36 comprises a crankshaft 62 with three eccentric 62.1, 62.2, 62.3, integral in rotation with the drive shaft 34, a secondary crankshaft 64 with three eccentric 64.1, 64.2, 64.3 rotating about an axis of revolution intermediate 140, a output gearwheel 66 of the freewheel 38, and which rotates about the second axis of revolution 120 and three toothed sectors 68.1, 68.2, 68.3 parallel. The secondary crankshaft 64 is journalled in rolling bearings mounted in flanges 70.1, 70.2 of the housing 42. The free end of the drive shaft 34 is also guided by a bearing of the flange 70.2. Each of the three gear sectors 68.1, 68.2, 68.3 is associated with one of the three eccentrics 62.1, 62.2, 62.3 of the engine crankshaft 62 and one of the three eccentrics 64.1, 64.2, 64.3 of the secondary crankshaft 64. More specifically, each of three toothed sectors 68.1, 68.2, 68.3 comprise an arm 72.1, 72.2, 72.3 having a drive opening 74.1, 74.2, 74.3 in which a bearing 76.1, 76.2, 76.3 is housed with one of the three eccentrics 62.1, 62.2, 62.3 the engine crankshaft 62, and a secondary opening 78.1, 78.2, 78.3 in which is housed a link bearing 80.1, 80.2, 80.3 with one of the three eccentrics 64.1, 64.2, 64.3 of the secondary crankshaft 64.

The three eccentric 62.1, 62.2, 62.3 of the engine crankshaft 62 have the same eccentricity and are offset at 120 ° from each other. The three eccentrics

64.1, 64.2, 64.3 of the secondary crankshaft 64 have the same eccentricity and are offset at 120 ° from each other in the same manner as the three eccentrics 62.1,

62.2, 62.3 of the engine crankshaft 62. The connection made by each toothed sector 68.1, 68.2, 68.3 between the associated eccentric 62.1, 62.2, 62.3 of the engine crankshaft 62 and the associated eccentric 64.1, 64.2, 64.3 of the secondary crankshaft 64 is kinematically an articulated parallelogram: the movement of each toothed sector is thus a circular translational movement, of radius equal to the eccentricity of the crankshafts. The circular translation movements of the three toothed sectors are shifted to 120 ° from each other. The toothed sectors 68.1, 68.2, 68.3 meshing successively with the toothed wheel 66, preferably each for at least one third of the motor shaft turn 34, in this case slightly more than one third of a turn, for example one third of turn plus two teeth of the toothed wheel 66, so as to achieve a recovery between the toothed sectors and ensure almost continuous transmission of movement. Cinematically, the oscillating eccentric speed reduction mechanism 36 is similar to a gear with external teeth that has the drive pinion in the small circle described by the sectors. teeth 68.1, 68.2, 68.3. It is thus possible to achieve very high reduction ratios, greater than 20 and preferably 30.

Naturally, what has been described with three toothed sectors 68.1, 68.2, 68.3 is transposable to four or more toothed sectors.

Claims

Cycle comprising at least one chain (28) of a given pitch, a pedal (18) rotating about a bottom bracket (100), the pedal (18) having at least two bottom plates (20, 22, 24) provided of teeth (26) at the pitch of the chain (28) and adapted to mesh with the chain (28), an electric assistance module (30) comprising an electric motor (32) comprising a motor shaft (34) rotating around a first axis of revolution (110) parallel to the bottom bracket axis (100), an output member (40) rotating about a second axis of revolution (120) parallel to the first axis of revolution (110) and remote of the first axis of revolution (110) and the crank axle (100), and a speed reduction mechanism (36) between the drive shaft (34) and the output member (40), characterized in that the output member (40) meshes with the teeth (26) of a first pedal plate (20, 22, 24) and the chain (28) meshes with the teeth (26) of a second plate to the bottom bracket (20, 22, 24) and in that the speed reduction mechanism (36) has a ratio between the revolution speed of the drive shaft (34) and the revolution speed of the output member ( 40) which, in absolute value, is greater than 20.

Cycle according to claim 1, characterized in that the first axis of revolution (110) is further from the axis of the pedal (100) than the second axis of revolution (120).

A cycle according to any one of the preceding claims, further comprising a frame (10), comprising a seat tube (12), a diagonal tube (14), and a bottom bracket tube (16) disposed at a lower end of the seat tube (12) and the diagonal tube (14), the pedal (18) having a bottom bracket bearing received in the bottom bracket tube (16), characterized in that the electric assist module (30) is attached to the diagonal tube (14).

4. Cycle according to claim 3, characterized in that the electric assistance module (30) is fixed under the diagonal tube (14) in a use position of the cycle.

5. Cycle according to any one of the preceding claims, characterized in that the output member (40) comprises meshing portions (48, 52, 58) equidistributed at a distance from each other at the pitch of the chain ( 28) about the second axis of revolution (120), each of the meshing portions (48, 52, 58) having a convex meshing face (60) projecting radially outwardly with, in a plane perpendicular to the second axis of revolution (120), a radius of curvature whose length varies less than 20% over an angular sector of at least 120 °, and a center of curvature located at a distance from the second axis of revolution greater than the radius of curvature .

6. Cycle according to claim 5, characterized in that the radius of curvature is constant over an angular sector of at least 120 °.

7. Cycle according to any one of claims 5 to 6, characterized in that the convex meshing face (60) of each of the drive portions (48, 52, 58) coincides with a cylindrical sector or a cylinder, axis (130) parallel to the second axis of revolution (120).

8. Cycle according to any one of claims 5 to 7, characterized in that the output member (40) comprises a flange (46) disposed perpendicularly to the second axis of revolution (120), carrying bars (48) s extending parallel to the second axis of revolution (120), equidistributed around the second axis of revolution (120) to a circular periphery of the flange (46), each of the bars (48) forming or carrying one of the meshing portions (48, 52).

9. Cycle according to any one of the preceding claims, characterized in that the pitch of the chain (28) is 12.6, 12.7 or 12.8 mm.

10. Cycle according to any one of the preceding claims, characterized in that the electrical assistance module (30) comprises a casing (42) for housing the motor and the gearbox, provided with means (44) for fixing a frame. (10) of the cycle.

1 1. Cycle according to claim 10, characterized in that the fixing means (44) comprise at least one support member (44A) fixed on the frame (10) of the cycle (11) and at least one removable locking member (44B). integral with the housing, adapted to lock the housing in at least one position relative to the support member (44A), and preferably to lock the housing (42) in a plurality of positions with respect to the support member ( 44A).

The cycle according to claim 11, characterized in that the support member (44A) defines a plurality of locking positions of the locking member (44B) located on the same rectilinear or circular path parallel to a perpendicular plane. at the first axis of revolution (110).

13. Cycle according to claim 11 or claim 12, characterized in that the locking member (44B) comprises a device for adjusting the position of the housing relative to the support member parallel to the first axis of revolution ( 110).

14. Cycle according to any one of the preceding claims, characterized in that the ratio between the revolution speed of the motor shaft (34) and the revolution speed of the output member (40) is, in absolute value. , greater than 30.

15. Cycle according to any one of the preceding claims, characterized in that the speed reduction mechanism (36) comprises a deformation wave gear.

16. Cycle according to any one of the preceding claims, characterized in that the speed reduction mechanism (36) comprises an oscillating eccentric gear.

17. Electrical assistance module (30) for a cycle according to any one of the preceding claims.