FR3142788A1 - Variable transmission with conical or frustoconical rollers and a crown - Google Patents

Abstract

The present invention relates to a variable transmission (1) using at least one conical or frustoconical input roller (6), a conical or frustoconical output roller (10) and a crown (8) cooperating with the conical or frustoconical rollers. and moving axially to vary the transmission ratio. For the invention, the generator (18, 19) of each roller (6, 10) in contact with the crown (8) is parallel to the input (2) and output (14) shafts of the variable transmission (1 ). Figure 1 to be published

Description

Variable transmission with conical or truncated rollers and a crown

The present invention relates to the field of variable transmissions, in particular for vehicles. In particular, the present invention relates to a variable transmission for an electrically assisted land vehicle.

In recent years, electrically assisted vehicles have been increasingly used, both for motor vehicles and for vehicles associated with so-called soft mobility such as two-wheelers, bicycles, tandems, three-wheelers, tricycles, cargo bikes, scooters, etc., as well as for the transport of goods (for example, motorized carts or electrically assisted trailers). This electrical assistance plays an important role in reducing pollutant and noise emissions, in the ease of use of these vehicles, while ensuring a reduction in the environmental impact of users.

For example, two-wheeled vehicles, such as bicycles, scooters, etc., may be equipped with at least one electric machine that provides additional assistance torque for driving the vehicle. In the case of bicycles, the electric machine may be associated with the pedal assembly, or directly associated with the driven wheel so as to assist the cyclist in these movements.

For these electrically assisted vehicles, choosing a suitable transmission is an important point. Indeed, an unsuitable transmission can cause difficulties in using the vehicle. Particularly for bicycles, in the vast majority of cases, the transmission gear change system is classic with the use of a derailleur system. Mastering this system is not simple and is not intuitive. The arrival of electrically assisted bicycles (EABs) has allowed a large number of people to access this mode of transport. Unfortunately, the transmission is still very poorly used most of the time, and the electric machine compensates for this, resulting in the use of the transmission in abnormal conditions (long gear permanently), which causes premature wear and breakage of these transmissions. In addition, cyclists prefer their pedaling frequency to remain constant, whatever the conditions, which is not possible with discrete gear transmissions.

Additionally, variable transmissions can have applications in other fields such as power generation, industry, etc.

• Les boîtes de vitesses, formées généralement d’un ensemble d’engrenages et utilisées habituellement pour les véhicules automobiles, elles présentent l’inconvénient principal de ne pas permettre une variation continue des rapports de réduction (rapports de réduction fixes et discrets),
• Les transmissions à variation continue CVT (de l’anglais « continuously variable transmission ») sont des boîtes de vitesses automatiques qui ne comportent pas un nombre prédéfini de rapports, au contraire, le rapport de transmission de telles transmissions reste positif et varie continument sur toute une plage de fonctionnement à l’intérieur d’une plage définie, les transmissions à variation continue CVT ont une ouverture limitée (valeur limitée entre le rapport de transmission le plus long et le rapport de transmission le plus court),
• Les transmissions infiniment variables IVT (de l’anglais « infinitly variable transmission ») sont des transmissions assurant une plage de variation infinie, qui permettent de passer des rapports de transmission négatifs (pour une marche arrière par exemple) à des rapports de transmission positifs (pour une marche avant par exemple) de façon continue, en passant par le rapport de transmission nul (qui correspond au point mort, rapport qui ne permet plus à l’élément moteur de transmettre de couple au véhicule).

There are different types of transmission for vehicles, including:

• Gearboxes, generally formed by a set of gears and usually used for motor vehicles, have the main disadvantage of not allowing continuous variation of the reduction ratios (fixed and discrete reduction ratios),
• Continuously variable transmissions (CVT) are automatic transmissions that do not have a predefined number of gears, on the contrary, the transmission ratio of such transmissions remains positive and varies continuously over an entire operating range within a defined range, CVT continuously variable transmissions have a limited opening (limited value between the longest and shortest transmission ratio),
• Infinitely variable transmissions (IVT) are transmissions that provide an infinite variation range, which allow you to move from negative transmission ratios (for example, for reverse) to positive transmission ratios (for example, for forward) continuously, passing through the zero transmission ratio (which corresponds to neutral, a ratio that no longer allows the engine element to transmit torque to the vehicle).

These last two types of transmission are called variable transmissions in the rest of the application, they are particularly suitable for a continuous variation of the transmission ratio, which favors their use within vehicles or for all types of applications.

These CVT and IVT variable transmissions can notably be obtained mechanically (for example by implementing an epicyclic gear train), pneumatically, hydraulically, or electrically.

One possibility of designing a mechanical IVT transmission is to combine the use of a CVT type toroidal variator for example with an epicyclic gear train, as implemented in the IVT transmission marketed in particular by the company Torotrack (Great Britain), and as described in particular in patent applications EP1042624, EP1155248, EP1846672, EP2882982.

CVT and IVT variable transmissions using an epicyclic gear train are respectively denoted CVP for continuously variable planetary gear train, and IVP for infinitely variable planetary gear train. Among mechanical variable transmissions, epicyclic gear trains using conical or truncated rollers as satellites have been developed. For this technology, the variation of the diameter of the conical or truncated rollers is used to continuously vary the transmission ratio.

The patent application with filing number FR21/11.388 concerns a variable transmission comprising an epicyclic gear train with planet gears in the form of conical or truncated rollers, as well as two internal planet gears and a planet carrier. However, the use of an epicyclic gear train makes the design more complex.

Furthermore, patent applications CN103711854 and CN103807394 describe variable transmissions with truncated rollers and a crown. The implementation of these conical rollers and the crown requires a complex movement of the crown that is not parallel to the axes of the input and output shafts, which implies complexity of assembly and implementation. In addition, such a crown does not have a naturally stable position; it must be held in place by external elements.

The aim of the invention is to design a compact and simple continuously variable transmission (in particular for varying the transmission ratio and for assembly), in order to facilitate its use within a vehicle. For this purpose, the present invention relates to a variable transmission implementing at least one conical or truncated input roller, one conical or truncated output roller and a crown cooperating with the conical or truncated rollers and moving axially to vary the transmission ratio. For the invention, the generator of each roller in contact with the crown is parallel to the input and output shafts of the variable transmission. Thus, the movement of the crown is parallel to the input and output shafts, which allows a simple and compact design of the transmission ratio variation system.

The invention further relates to a land vehicle implementing such a variable transmission.

The invention relates to a variable transmission, in particular for a vehicle, comprising an input shaft, at least one conical or frustoconical input roller driven by an input roller shaft cooperating with said input shaft by means of a first gear, an output shaft, at least one conical or frustoconical output roller driving an output roller shaft cooperating with said output shaft by means of a second gear and a crown cooperating by friction with each input roller and each output roller. Said crown cooperates with each input roller and each output roller at a generator parallel to said input shaft and said output shaft, and in that said variable transmission comprises a means for moving said crown parallel to said input shaft and said output shaft.

According to one embodiment, each input roller and each output roller are arranged in the axial direction of said crown, such that the smallest diameter of each input roller substantially faces the largest diameter of the output roller and the largest diameter of each input roller substantially faces the smallest diameter of the output roller.

According to one implementation, said crown moving means comprises at least one adjustment actuator or at least one fork for axially moving said crown.

According to one aspect, each input roller and/or each output roller comprises a ramp mechanism for adjusting the contact pressure with said crown.

According to one embodiment, said input shaft is coaxial with said output shaft.

According to one configuration, said input shaft and/or said output shaft is coaxial with said crown.

According to one embodiment, said input shaft and/or said output shaft is outside said crown.

Furthermore, the invention relates to a land vehicle, preferably electrically assisted, comprising at least one wheel, a first drive source, optionally an electric machine connected to an electric battery, and a variable transmission according to one of the preceding characteristics for transmitting rotation between said first drive source and/or optionally the electric machine and said at least one wheel.

According to one implementation, said first drive source is a crankset, and the variable transmission is arranged in said crankset.

Advantageously, said land vehicle is a two-wheeler or a tricycle, in particular a bicycle.

According to one aspect, said land vehicle is electrically assisted, comprising a powertrain formed by said electric machine and said variable transmission.

Other characteristics and advantages of the system according to the invention will appear on reading the following description of non-limiting examples of embodiments, with reference to the figures appended and described below.

List of figures

There illustrates a sectional view of a variable transmission according to a first embodiment of the invention.

Figures 2A to 2D illustrate different variant embodiments of a variable transmission according to the invention.

Figures 3A to 3C illustrate different variant embodiments of a variable transmission according to the invention.

Figures 4A to 4D illustrate different variant embodiments of a variable transmission according to the invention.

Figures 5A and 5B illustrate different variant embodiments of a variable transmission according to the invention.

The present invention relates to a variable transmission. In other words, the present invention relates to a transmission of the type of continuously variable transmission CVT or infinitely variable transmission IVT.

• Un arbre d’entrée, apte à être connecté à un entraînement par exemple une machine électrique ou un pédalier,
• Au moins un galet d’entrée conique ou tronconique, chaque galet d’entrée est entraîné par un axe de galet d’entrée (chaque galet d’entrée est monté sur un axe de galet d’entrée), et chaque axe de galet d’entrée coopère avec l’arbre d’entrée au moyen d’un engrenage (appelé engrenage d’entrée),
• Un arbre de sortie, apte à entraîner directement ou indirectement une charge, par exemple une roue d’un véhicule,
• Au moins un galet de sortie conique ou tronconique, chaque galet de sortie entraîne un axe de galet de sortie (chaque galet de sortie est monté sur un axe de galet de sortie), et chaque axe de galet de sortie coopère avec l’arbre de sortie au moyen d’un engrenage (appelé engrenage de sortie), et
• Une couronne qui coopère par friction avec chaque galet d’entrée et chaque galet de sortie, la couronne entourant les galets d’entrée et de sortie (on parle de couronne, car c’est la partie intérieure de la couronne qui coopère avec chaque galet d’entrée et chaque galet de sortie).

According to the invention, the transmission comprises:

• An input shaft, suitable for connection to a drive such as an electric machine or a pedal drive,
• At least one conical or truncated input roller, each input roller is driven by an input roller shaft (each input roller is mounted on an input roller shaft), and each input roller shaft cooperates with the input shaft by means of a gear (called an input gear),
• An output shaft, capable of directly or indirectly driving a load, for example a wheel of a vehicle,
• At least one conical or truncated conical output roller, each output roller drives an output roller shaft (each output roller is mounted on an output roller shaft), and each output roller shaft cooperates with the output shaft by means of a gear (called an output gear), and
• A crown that cooperates by friction with each input roller and each output roller, the crown surrounding the input and output rollers (we speak of crown, because it is the interior part of the crown that cooperates with each input roller and each output roller).

With this configuration, a transmission is achieved between the input shaft and the output shaft. The movement is transmitted successively from the input shaft, to the input roller axis and therefore to the input roller, then to the crown, then to the output roller and therefore to the output roller axis, and finally to the output shaft. This transmission therefore implements two gears and two friction cooperations. This transmission is made variable by moving the crown along the generatrices of the input and output rollers. Indeed, the conical or truncated cone shape of the input and output rollers makes it possible to vary the distance between the axis of the input rollers and the point of contact of the input roller with the crown, as well as between the axis of the output rollers and the point of contact of the output roller with the crown and consequently to vary the transmission ratio between each input roller and the crown, and between the crown and each output roller.

According to the invention, the crown cooperates with each input roller and each output roller at a generatrix of each input roller and each output roller, this generatrix being parallel to the input and output shafts of the variable transmission. In other words, the contact force between the crown and each roller is perpendicular to the input shaft and the output shaft. For this, the axis of each input roller and the axis of each output roller is inclined relative to a parallel to the input and output shafts of the variable transmission. Thus, the input and output rollers are arranged such that their external generatrices, in contact with the crown, are parallel to each other and are parallel to the axis of rotation of the crown. This allows for natural automatic maintenance of the crown in its axial position.

In addition, the crown moves axially parallel to said input and output shafts. For this movement, the variable transmission comprises a means for moving the crown. This axial displacement movement is a translation, which allows the variation of the transmission ratio. Thus, the design of the variable transmission is simplified: the movement of the crown is not in a different direction to that of the input shaft and the output shaft. In addition, due to this parallelism, the variable transmission is compact.

Advantageously, the number of input rollers may be different or equal to the number of output rollers. Additionally or alternatively, the sum of the number of input rollers and the number of output rollers may be between 2 and 8, or even more if the dimensions of the transmission allow it. A plurality of input and/or output rollers allows a better distribution of forces within the transmission.

Advantageously, when the variable transmission comprises several input rollers, these input rollers may be distributed regularly or not around the axis of the crown (i.e. the axis of rotation and axial movement of the crown). Additionally or alternatively, when the variable transmission comprises several output rollers, these output rollers may be distributed regularly or not around the axis of the crown. Additionally or alternatively, when the variable transmission comprises several input rollers and several output rollers, these input and output rollers may be distributed alternately (in other words an input roller is located between two output rollers and vice versa) or not around the axis of the crown.

According to one embodiment of the invention, the input and output rollers may be arranged in an axial direction of the crown such that the smaller diameter of each input roller faces the larger diameter of each output roller, and such that the larger diameter of each input roller faces the smaller diameter of each output roller. In other words, the input and output rollers are arranged head to tail, or otherwise expressed in the opposite direction. Thus, when the crown is in contact with the larger diameter of the input roller, the crown is in contact with the smaller diameter of the output roller and vice versa. This construction allows a variation of the transmission ratio, while maintaining a compactness of the variable transmission.

According to one implementation of the invention, the means for moving the crown wheel may comprise at least one adjustment actuator or at least one fork for axial movement of the crown wheel. The adjustment actuator may also be called an adjustment roller, which may be a roller driving the crown wheel in axial movement, the roller being slidably mounted on an axis parallel to the input shaft and the output shaft. A fork may be such as that used in a gearbox. These crown wheel movement systems are simple and compact. Advantageously, the variable transmission may comprise a plurality of adjustment actuators arranged around the crown wheel to facilitate movement of the crown wheel.

Advantageously, the variable transmission may comprise control means, capable of controlling the position of the adjustment actuator or the fork. These control means may in particular be electrical, pneumatic, hydraulic or mechanical.

According to one aspect of the invention, each input roller and/or each output roller may comprise a ramp mechanism for adjusting the contact pressure between the roller and the crown. The contact pressure may advantageously be adjusted as a function of the torque to be transmitted. This device makes it possible, under the effect of the transmitted torque, to induce a slight displacement of the input roller or the output roller along its axis, thus causing a wedging effect in the crown. This wedging effect results in increasing the contact pressure between the crown and the input roller or the output roller. This results in a modulation of the contact pressure as a function of the transmitted torque.

According to one embodiment option, the input shaft may be coaxial with the output shaft. This coaxiality allows in particular a simplification of the variable transmission, and allows, if necessary, installation within a crankset. For this embodiment option, the output shaft may be in pivot connection with respect to the input shaft. Alternatively, the input and output shafts may not be coaxial (but are parallel). This implementation makes it possible to avoid having to manage concentric guides, and may allow, if necessary, to implement the output plate differently.

In one aspect, the input shaft may be coaxial with the crown, allowing for installation within a crankset if desired. Alternatively, the input shaft may not be coaxial with the crown (but they are parallel). This alternative allows for limiting the ground clearance of the transmission. In addition, when the input shaft is not coaxial with the crown, it may be inside the crown (in other words, the input shaft passes through the crown), thereby minimizing the radial size of the variable transmission, and allowing for installation within a crankset if desired. Alternatively, when the input shaft is not coaxial with the crown, it may be outside the crown. In other words, the input shaft does not pass through the crown. This implementation makes it possible to avoid having to manage concentric guides, to limit the ground clearance of the transmission, and can allow, if necessary, to implement the output plate differently.

Alternatively or cumulatively, the output shaft can be coaxial with the crown, allowing installation within a crankset if necessary. Alternatively, the output shaft may not be coaxial with the crown (but they are parallel). This variant makes it possible to limit the ground clearance of the transmission. In addition, when the output shaft is not coaxial with the crown, it can be inside the crown (in other words, the output shaft passes through the crown), thus minimizing the radial size of the variable transmission and allowing installation within a crankset if necessary. Alternatively, when the output shaft is not coaxial with the crown, it can be outside the crown. In other words, the output shaft does not pass through the crown. This implementation makes it possible to avoid having to manage concentric guides, to limit the ground clearance of the transmission, and can make it possible, if necessary, to implement the output chainring differently.

Thus, according to a configuration of the invention, the input shafts, output shafts and the crown can be coaxial. Thus, the input and output shafts are arranged in the center of the crown. This configuration of the invention allows a compact diameter of the variable transmission.

According to one feature, the two gears, respectively input gear and output gear, may be bevel gears, in order to facilitate their drive given the inclination of the axis of the input and output rollers relative to the input and output shafts. Furthermore, the gears may be external gears or internal gears (i.e. with external or internal teeth), preferably external gears to limit the radial size.

In one embodiment, each gear may be located on the side of each input or output roller having the largest diameter. This configuration may be preferred if a low gear ratio is used between the input shaft and the input roller. Alternatively, each gear may be located on the side of each input or output roller having the smallest diameter. This configuration may be preferred if a high gear ratio is used between the input shaft and the input roller.

According to one implementation, a high multiplication ratio may be provided between the input shaft and the input roller (at the gearing between these two elements) in order to increase the speed of the input roller. This makes it possible to reduce the torque to be transmitted between the input roller and the crown.

According to an exemplary embodiment, the variable transmission may be mounted in a housing (for example, in the frame of a bicycle: at the crankset, or in a housing of a powertrain comprising an electric machine and the variable transmission). In this case, the input and output shafts as well as the axes of the input and output rollers may be in pivot connection relative to the housing, and the crown may be in pivot-sliding movement relative to the housing.

According to one embodiment, each input roller can be identical (shape and dimensions) to each output roller, which facilitates assembly as well as manufacturing (only one type of conical or truncated roller is then manufactured).

The various connections (pivot, pivot-sliding, translation) within the variable transmission can be achieved by any means, in particular by ball bearings, ball slides, roller bearings, bearings, etc.

There illustrates, schematically and in a non-limiting manner, a variable transmission 1 according to an embodiment of the invention. The is a view in the axial direction (of the section type whose cutting plane passes through the input and output axes) of the variable transmission. The variable transmission is arranged within a housing 16. The variable transmission 1 comprises an input shaft 2. For the illustrated embodiment, the input shaft 2 is a shaft of a pedal assembly 17. However, the input shaft 2 can be driven by other mechanisms such as an electric machine (not shown). The input shaft 2 is pivotally connected to the housing 16. The input shaft 2 drives a toothed wheel 3. The toothed wheel 3 drives a toothed wheel 4 which is fixed on an input roller shaft 5. The input roller shaft 5 is pivotally connected to the housing 16. The input roller shaft 5 drives an input roller 6 which is frustoconical. For the illustrated embodiment, the toothed wheel 4 is on the side of the larger diameter of the input roller 6. The input roller 6 has a generator 18 which is parallel to the input shaft 2. In addition, a ramp mechanism 7 is provided on the input roller 6. The generator 18 of the input roller 6 cooperates by friction with the inner surface of a crown 8. The crown 8 is moved axially (double arrow) by an adjustment actuator 9 which is slidable on an axis 20, to vary the transmission ratio of the variable transmission. The axis 20 is parallel to the input shaft 2 and is fixed in the housing 16. The crown 8 also cooperates with a generator 19 of a truncated cone-shaped output roller 10. The output roller 10 may be identical in terms of dimensions and shape to the input roller 6. In addition, the output roller 10 is arranged head to tail with respect to the input roller 6 (in the figure, the largest diameter of the input roller 6 is on the same side of the housing 16 as the smallest diameter of the output roller 10, while on the opposite side are arranged the largest diameter of the output roller 10 and the smallest diameter of the input roller 6). The output roller 10 drives an output roller shaft 11. The output roller shaft 11 is pivotally connected within the housing 16. The output roller shaft 11 comprises a gear wheel 12 which cooperates with a gear wheel 13. For the illustrated embodiment, the gear wheel 12 is on the larger side of the output roller 10. The gear wheel 13 is fixed to the output shaft 14 of the transmission. The output shaft 14 is pivotally connected relative to the housing 16 and pivotally connected relative to the input shaft 2. The generatrix 19 of the output roller 10 is parallel to the input shaft 2 and to the output shaft 14 of the transmission. For the illustrated embodiment, the output shaft 14 of the transmission comprises a toothed wheel 15 for indirectly driving (e.g. by means of a belt or chain) a wheel of a vehicle. For the illustrated embodiment, the input shaft 2, the output shaft 14 and the crown wheel 8 are coaxial. However, the output shaft 14 may be driven by other mechanisms such as an electric machine (not shown)

Figures 2 to 5 illustrate, schematically and in a non-limiting manner, different variant embodiments of the invention. These figures are partial sections (not all the components are shown) along section AA of the . In these figures, the input and output rollers are not circular, because they are in the section plane AA which is not perpendicular to their respective axes.

Figures 2A to 2D illustrate four configurations of the input and output rollers according to alternative embodiments of the invention. In these figures, only the crown 8, the input 6 and output 10 rollers and their axes 5 and 11 are shown.

For the variant of Figure 2A, the variable transmission comprises an input roller 6 and an output roller 10. For this variant, the input roller 6 is diametrically opposite the output roller 10 within the crown 8.

For the variant of Figure 2B, the variable transmission comprises an input roller 6 and an output roller 10. For this variant, the output roller 10 is offset relative to the diameter which passes through the input roller 6.

For the variant of Figure 2C, the variable transmission comprises two input rollers 6 and two output rollers 10. For this variant, each input roller 6 is diametrically opposite an output roller 10.

For the variant of Figure 2D, the variable transmission comprises two input rollers 6 and two output rollers 10. For this variant, the input rollers 6 are diametrically opposed to each other and the output rollers 10 are diametrically opposed to each other.

Figures 3A to 3C illustrate three configurations of the adjustment actuator. In these figures, only the crown 8, the input 6 and output 10 rollers, their axes 5 and 11 and the adjustment rollers 9 are shown. The variants of Figures 3A to 3C are illustrated with an input roller 6 and an output roller 10, in accordance with the variant of Figure 2A. However, the variants of Figures 3A to 3C can be combined with the embodiment variants of Figures 2A to 2D.

For the variant of Figure 3A, the transmission comprises an adjustment actuator 9 which is arranged on the outer part of the crown 8 opposite the input roller 6.

For the variant of Figure 3B, the transmission comprises an adjustment actuator 9 which is arranged on the outer part of the crown 8 in a position offset relative to the input roller 6 and the output roller 10.

For the variant of Figure 3C, the transmission comprises three adjustment actuators 9 which are arranged on the outer part of the crown. One of the adjustment actuators 9 is arranged opposite the input roller 6. The other two actuators are in positions offset from the input roller 6 and the output roller 10. The position and number of rollers is not limited to the variants shown. .

Figures 4A to 4D, 5A and 5B illustrate six configurations of the input and output shafts of the variable transmission relative to the crown. In these figures, only the crown 8, the input 6 and output 10 rollers, their axes 5 and 11, the input shaft 2, and the toothed wheels 3, 4, 12 and 13 are shown. The variants of Figures 4A to 4D, 5A and 5B are illustrated with an input roller 6 and an output roller 10, in accordance with the variant of Figure 2A. However, the variant embodiments of Figures 2A to 2D and 3A to 3C can be combined with the variant embodiments of Figures 4A to 4D, 5A and 5B.

For the variant of Figure 4A, the input shaft 2, the output shaft (not shown but linked to the toothed wheel 13) and the crown 8 are coaxial. Thus, the input and output shafts 2 and their toothed wheels 3 and 13 are at the center of the crown 8.

For the variant of figure 4B, the input shaft 2 and the output shaft (not shown but linked to the toothed wheel 13) are coaxial, inside the crown but without being coaxial with the crown 8.

For the variant of Figure 4C, there is no coaxiality between the input shaft 2, the output shaft (not shown but linked to the toothed wheel 13) and the crown 8. In addition, the input 2 and output shafts are inside the crown 8.

For the variant of Figure 4D, there is no coaxiality between the input shaft 2, the output shaft (not shown but linked to the toothed wheel 13) and the crown 8. In addition, the input shaft 2 is outside the crown 8, while the output shaft is inside the crown 8.

For the variant of Figure 5A, there is no coaxiality between the input shaft 2, the output shaft (not shown but linked to the toothed wheel 13) and the crown 8. In addition, the input shaft 2 is outside the crown 8, and the output shaft is outside the crown 8.

For the variant of Figure 5B, there is no coaxiality between the input shaft 2, the output shaft (not shown but linked to the toothed wheel 13) and the crown 8. In addition, the input shaft 2 is inside the crown 8, and the output shaft is outside the crown 8.

The present invention also relates to a land vehicle, preferably electrically assisted. The land vehicle comprises at least one wheel, and may be of any type, in particular a motor vehicle, a two-wheeler, a bicycle, a tandem, a three-wheeler, a tricycle, a cargo bike, a scooter, a trailer, a transport cart, etc. Where appropriate, the vehicle is said to be electrically assisted, because the vehicle comprises a first drive source providing traction of the vehicle, in particular by driving at least one wheel of the vehicle, as well as an electric machine providing assistance with the drive (the electric machine is considered to be a second drive source).

The primary drive source can be of any type, an internal combustion engine, a pedal, a crank, a handle, a hydraulic system, a pneumatic system, etc.

Preferably, the invention relates to a two-wheeler, a bicycle, a cargo bike, a tricycle, a trailer, such as a bicycle trailer. Indeed, the invention is particularly suitable for this type of vehicle. Very preferably, the invention relates to an electrically assisted bicycle, a cargo bike, or a bicycle towing a trailer. Indeed, the invention integrates well on this type of vehicle and allows optimized assistance at the level of the pedal assembly of the vehicle. For this preferred implementation, the first drive source can be a pedal assembly actuated by a user (cyclist). In addition, the electric machine can be placed in the hub of the pedal assembly, which facilitates its integration. Alternatively, the electric machine can be placed on the driven wheel or on a non-driven wheel, which makes it possible to limit the space requirement at the level of the pedal assembly. Furthermore, for this implementation, the transmission can be located at the pedal level or at the wheel level or within a powertrain.

• Au moins une roue,
• Une première source d’entraînement, et
• Une transmission variable selon l’une quelconque des variantes ou des combinaisons de variantes décrites ci-dessus, pour transmettre un couple entre la première source d’entraînement et l’au moins une roue.

Thus, the land vehicle includes:

• At least one wheel,
• A first source of training, and
• A variable transmission according to any of the variants or combinations of variants described above, for transmitting torque between the first drive source and the at least one wheel.

• Au moins une roue,
• Une première source d’entraînement,
• Une machine électrique connectée par une batterie électrique (pour l’alimentation électrique voire pour la récupération d’énergie), et
• Une transmission variable selon l’une quelconque des variantes ou des combinaisons de variantes décrites ci-dessus, pour transmettre un couple entre la première source d’entraînement et/ou la machine électrique et l’au moins une roue.

In addition, the electrically assisted land vehicle includes:

• At least one wheel,
• A first source of training,
• An electric machine connected by an electric battery (for the power supply or even for energy recovery), and
• A variable transmission according to any of the variants or combinations of variants described above, for transmitting torque between the first drive source and/or the electric machine and the at least one wheel.

Thus, a transmission/multiplication ratio of a transmission that varies continuously is possible between the electric machine and/or the first drive source and the at least one wheel. In addition, the transmission according to the invention makes it possible to have a variable transmission/multiplication ratio for one drive source and a fixed transmission/multiplication ratio for the other drive source. For an application to bicycles, the variable transmission provides the possibility of controlling and maintaining a constant pedaling frequency of the cyclist regardless of the profile of the road or path taken by the bicycle. Thus, for the cyclist, the use of the transmission system is simplified.

Advantageously, the land vehicle may further comprise a controller which controls the variable transmission and/or the electric machine.

According to one embodiment of the invention, the variable transmission may be mounted in the hub of the driven wheel. For example, the housing of the variable transmission may constitute the hub of the wheel (and in the case of a bicycle, this hub may carry the spokes of the wheel).

Alternatively, the variable transmission may be mounted in the first drive source. If desired, the variable transmission may be mounted in the pedal assembly of the land vehicle. In this case, the input shaft of the variable transmission may be the pedal assembly axle, for example in accordance with the implementation of the . Alternatively, the variable transmission and the electric machine may for example be mounted in the same casing, thus forming a powertrain. For this embodiment, the input shaft of the variable transmission may be the shaft of the electric machine. Alternatively, for this embodiment, the variable transmission and the electric machine may be mounted in different casings. Alternatively, an electric machine may be associated with the output shaft. This configuration makes it possible to limit the dimensioning of the variable transmission by reserving this variable transmission for the muscular power of the cyclist.

It goes without saying that the invention is not limited to the embodiments of the variable transmission and the vehicle described above as examples; on the contrary, it encompasses all variant embodiments.

Claims (11)

Variable transmission, in particular for a vehicle, comprising an input shaft (2), at least one conical or frustoconical input roller (6) driven by an input roller shaft (5) cooperating with said input shaft (2) by means of a first gear (3, 4), an output shaft (14), at least one conical or frustoconical output roller (10) driving an output roller shaft (11) cooperating with said output shaft by means of a second gear (12, 13) and a crown (8) cooperating by friction with each input roller (6) and each output roller (10), characterized in that said crown (8) cooperates with each input roller (6) and each output roller (10) at a generator (18, 19) parallel to said input shaft (2) and said output shaft (14), and in that said variable transmission (1) comprises means of displacement (9) of said crown (8) parallel to said input shaft (2) and to said output shaft (14). Variable transmission according to claim 1, wherein each input roller (6) and each output roller (10) are arranged in the axial direction of said ring gear (8), such that the smaller diameter of each input roller (6) substantially faces the larger diameter of the output roller (10) and the larger diameter of each input roller (6) substantially faces the smaller diameter of the output roller (10). Variable transmission according to one of the preceding claims, wherein said means for moving the crown comprises at least one adjustment actuator (9) or at least one fork for axially moving said crown. Variable transmission according to one of the preceding claims, in which each input roller (6) and/or each output roller (10) comprises a ramp mechanism (7) for adjusting the contact pressure with said crown (8). Variable transmission according to one of the preceding claims, in which said input shaft (2) is coaxial with said output shaft (14). Variable transmission according to one of the preceding claims, in which said input shaft (2) and/or said output shaft (14) is coaxial with said crown (8). Variable transmission according to one of the preceding claims, wherein said input shaft (2) and/or said output shaft (14) is outside said crown (8). Land vehicle, preferably electrically assisted, comprising at least one wheel, a first drive source, optionally an electric machine connected to an electric battery, and a variable transmission (1) according to one of the preceding claims for transmitting rotation between said first drive source and/or optionally the electric machine and said at least one wheel. Land vehicle according to claim 8, wherein said first drive source is a pedal assembly (17), and wherein the variable transmission (1) is arranged in said pedal assembly. Land vehicle according to one of claims 8 or 9, in which said land vehicle is a two-wheeler or a tricycle, in particular a bicycle. Land vehicle according to one of claims 8 to 10 with electrical assistance, comprising a powertrain formed by said electric machine and said variable transmission.