FR3135957A1 - Training device for electrically assisted bicycle - Google Patents

Abstract

Drive device (1) for an electrically assisted bicycle comprising at least one rear wheel (5), said drive device comprising a housing (3) housing a bottom bracket axle (2) coupled to a motor via a transmission, a chain (4) or belt connecting the bottom bracket axle (2) to the rear wheel (5) of the bicycle, the drive device also comprising a chain (4) or belt tensioner (6) comprising a fixing support (7) to the housing (3), a clamping roller (8) pivotally mounted on the support (7) so as to exert a clamping force on the chain (4) or belt. FIGURE 1

Description

Training device for electrically assisted bicycle

The present invention relates to a drive device for an electrically assisted bicycle comprising at least one rear wheel, said drive device comprising a housing housing a bottom bracket axle coupled to a motor via a transmission, a chain or belt connecting the bottom bracket axle to the rear wheel of the bicycle.

Electric-assisted bicycles are becoming more and more widespread. The power delivered by the motor is coupled to that supplied by the cyclist via the crankset, thereby reducing the cyclist's effort. Such bicycles make it possible, for example, to make long journeys while reducing the cyclist's effort, or to make journeys with a significant difference in altitude.

Electric-assisted bicycles generally include an electric motor, a battery, and assistance control or management means allowing the cyclist to activate or deactivate the assistance and in certain cases to manage the intensity level of the assistance. assistance. The controls are often located at the level of the bicycle handlebars, for manual operation with the fingers.

The driving force is often transmitted to the rear wheel by a chain or belt. To allow use in the most varied conditions, even the most difficult, the chain is often kept in tension by a classic chain tensioner or derailleur, most often placed in relation to the rear wheel. The latter is then equipped with a mechanical component likely to make the assembly and disassembly operations of the rear wheel complex.

We also know a tensioner arrangement along the frame, for example as described in document EP3951212 which describes a belt tensioner for a bicycle. The tensioner is fixed to a base of the frame, between the rear wheel and the crankset. A screw serves as a tension regulator, making it easier to adjust the belt tension level.

For several years, the demand for this type of bicycle has been constantly growing and most manufacturers are unable to produce sufficient quantities in a reasonable time.

The success of these bikes also has consequences in terms of after-sales service and maintenance. Here again, the workshops do not meet demand and users are offered particularly long deadlines to carry out repairs, even the simplest.

There is therefore a need for an electrically assisted bicycle which is simpler, easy and quick to assemble, and easy to maintain by non-specialists.

To overcome these various drawbacks, the invention provides different technical means.

First of all, a first objective of the invention consists of providing an electrically assisted bicycle of simple design, allowing rapid assembly.

Yet another objective of the invention consists of providing an electrically assisted bicycle that is easy to maintain by a non-specialist, in particular for the most frequent repairs such as punctures or tire changes.

To do this, the invention provides a drive device for an electrically assisted bicycle comprising at least one rear wheel, said drive device comprising a housing housing a bottom bracket axle coupled to a motor via a transmission, a chain or belt connecting the bottom bracket axle to the rear wheel of the bicycle, the drive device also comprising a chain or belt tensioner comprising a support for fixing to the housing, a tightening roller pivotally mounted on the support so as to exert a force tightening on the chain or belt.

This architecture makes it possible to integrate all the key elements of the engine chain at the front or in the middle position of the bike, to free the rear wheel. It is not necessary to have a rear derailleur to tension the chain. This simplifies maintenance operations relating to the rear wheel, which can be carried out by non-specialists in bicycle mechanics. The tensioner, thanks to its clearance and its position, allows the wear of the chain to be recovered over time (elongation) and allows easy disassembly of the rear wheel without requiring adjustment at each disassembly-reassembly. It adapts easily with motors with integrated gearboxes or with fixed gear bikes (without gears on the rear cassette), since the latter do not have a rear derailleur.

This arrangement also makes it possible to simplify the manufacture and assembly of the bicycle, with a modular assisted pedal assembly comprising all the elements ready for assembly on the frame of the bicycle to be manufactured. The chain or belt can then be coupled to the rear wheel of the bicycle to complete the motor assembly.

Advantageously, the fixing support comprises two spaced fixing lugs for fixing to the housing.

This arrangement is simple and inexpensive. Due to the volume of the housing which envelops the crank axle, the fixing lugs fixed for example behind the crank axle allow optimal positioning of the tensioner to act at the level of the chain or belt in the immediate vicinity of the chainring, avoiding a too long overhang which would weaken the tensioner. This arrangement makes it easier to assemble the drive device at the factory before assembling the bike. Later, during the life of the bike, the tensioner can easily be replaced or simply adjusted.

Also advantageously, the tensioner comprises a pivot pin carrying a pivoting arm on which the clamping roller is mounted via a roller pin, a clamping spring being integrated into the pivot pin, so that the clamping force exerted by the clamping roller comes from the spiral spring.

The spring is calibrated to provide a level of tension suitable for the type of bike. The tension level allows easy operation of the chain or belt, while minimizing the risk of it derailing from the drive plate due to an insufficient tension level.

The pivoting arm allows a range of tensioner travel taking into account the length of the chain or belt as well as its wear, aiming for a constant tightening tension over time. This also simplifies the assembly of the chain or belt and allows a wider range of lengths of new chains or belts to be accepted. As a result, a larger range of references for new chains or belts (of different lengths) can be assembled, avoiding having to cut them to measure.

According to an advantageous embodiment, the fixing lugs comprise oblong fixing holes oriented at different angles.

This arrangement makes it possible to adjust the initial position of the tensioner during the first assembly and to adapt this position to a given chain length subsequently.

“V” TENSIONER

According to an advantageous embodiment, the pivot axis is in the middle position of the tensioner, between the fixing lugs and the clamping roller.

This embodiment is simple, reliable and inexpensive to produce.

TENSIONER WITH RETAINING SLOT

According to another advantageous embodiment, the fixing lugs and the pivot axis are arranged on either side of the fixing support, the roller axis cooperating with a roller guide slot arranged between the fixing lugs and the pivot pin.

Advantageously, the roller guide slot forms an arc of a circle whose radius corresponds to the distance between the pivot axis and the slot.

Such an arrangement allows the pivot axis to be at the opposite end of the support facing the fixing lugs. The free end of the swivel arm is held by the guide slot. This architecture makes it possible to solidify the pivoting arm which is secured at its two ends. In the event of lateral stress on the chain, the force is absorbed by the support.

The invention also provides a tensioner for a drive device for an electrically assisted bicycle as previously described.

The invention finally provides an electrically assisted bicycle comprising a training device as previously described.

All the implementation details are given in the description which follows, supplemented by Figures 1 to 8 presented solely for the purposes of non-limiting examples, and in which:

Fig.1

there is a side view of a first example of a drive device for an electrically assisted bicycle;

Fig.2

there shows the example of installed on an electrically assisted bicycle, with the chain mounted on the rear wheel of the bicycle;

Fig.3

there is a side view of the tensioner used with the example of the ;

Fig.4

there is a perspective view of the tensioner used with the example of the ;

Fig.5

there is a side view of a second example of a drive device for an electrically assisted bicycle;

Fig.6

there shows the example of installed on an electrically assisted bicycle, with the chain mounted on the rear wheel of the bicycle;

Fig.7

there is a front view of the tensioner used with the example of the ;

Fig.8

there is a rear view of the tensioner used with the example of the .

Figures 1 and 2 illustrate a first embodiment of a training device 1 for an electrically assisted bicycle. Conventionally, the bicycle has at least one rear wheel 5 and one front wheel. As illustrated, a housing 3 accommodates a motor coupled to a transmission. These elements make it possible to provide motor assistance to the bottom bracket axle 2 cooperating with the transmission. Depending on the model, the assistance level is adjusted either with a manual control, for example connected to the handlebars, or automatically, for example according to the effort received by the pedal axle 2.

The bottom bracket axle carries a plate 14 on which is mounted a chain 4 or a belt connecting the bottom bracket axle 2 to the rear wheel 5 of the bicycle.

The drive device 1 also includes a chain 4 or belt tensioner 6. As illustrated in the enlarged views of Figures 3 and 4, the tensioner 6 comprises a fixing support 7 to the housing 3, allowing the tensioner to be fixed on one side of the housing 3, in the low position, behind the bottom bracket axle. In the example illustrated, the fixing support 7 is screwed behind the bottom bracket axle 2 via oblong fixing holes 15. These holes 15 are preferably oriented at different angles, to allow the tensioner to be positioned and adjusted according to different positions and orientations. The fixing holes 15 are provided on two fixing lugs 9 spaced apart from each other, formed at the level of the fixing support.

A pivoting arm 11 is fixed to the fixing support 7 by a pivot pin 10. This pivoting arm 11 carries a clamping roller 8 mounted on the roller pin 12. As illustrated in Figures 1 and 2, the pivoting arm 11 and the tightening roller 8 are oriented towards the rear of the housing 3 and the plate 14, so that the tightening roller is under the lower sector of the chain.

To tension the chain 4 or the belt, a calibrated tightening or tension spring is arranged between the pivoting arm 11 and the fixing support 7. A torsion spring (not shown) with a rectangular or spherical section integrated into the level of the pivot axis 10. The arrangement of the spring facing the pivoting arm and the support is provided so that the clamping roller 8 exerts a supporting force on the chain or belt, as shown in Figures 1 and 2, preferably to push the latter upwards, to increase the winding length on the plate 14 and contribute to better retention in place on the plate.

This architecture makes it possible to design a modular training device, easy and quick to integrate into a bicycle frame. The tensioner allows you to adjust the level of tightening of the chain or belt in order to reduce or eliminate the risk of derailment. This arrangement also makes it possible to compensate for wear and elongation of the chain or belt, by ensuring constant tension. This is static when the bike is stationary but also dynamic, when the chain undergoes accelerations on the vertical axis due to any factor coming from the external environment and/or driving the bike such as for example roughness in the road. /path, a jumping movement of the cyclist, etc. Without the tensioner device, this movement previously described could result in damage to the frame due to contact with the chain, or an alteration of the engagement of the chain or belt on the front chainring which could cause derailment of the chain or belt.

“V” TENSIONER

In the exemplary embodiment of Figures 1 to 4, the pivot axis 10 is arranged between the fixing lugs 9 of the support 7 and the clamping roller 8. The clamping roller 8 is mounted cantilevered at the free end of the pivoting arm 11. This embodiment is simple in design, has few parts and makes it possible to produce an effective and reliable tensioner at low cost.

TENSIONER WITH RETAINING SLOT

Figures 5 to 8 illustrate a second embodiment in which the arrangement of the tensioner 6 is more compact, and the clamping roller 8 is secured against the fixing support 7. For this purpose, the support 7 has a guide slot 13 arranged in the middle zone of the support, between the fixing lugs 9 and the pivot axis 10. The guide slot forms an arc of a circle whose radius corresponds to the distance between the pivot axis 10 and the slot. The roller axis 12 extends out of the roller and cooperates with the slot 13. The length of the slot is designed to offer sufficient clearance to provide a level of tension of the chain or belt limiting or eliminating the risk of derailment, while providing smooth and efficient operation.

This embodiment provides support at both ends of the pivoting arm 11, improving the rigidity and solidity of the tensioner.

Claims (9)

Drive device (1) for an electrically assisted bicycle comprising at least one rear wheel (5), said drive device comprising a housing (3) housing a bottom bracket axle (2) coupled to a motor via a transmission, a chain (4) or belt connecting the bottom bracket axle (2) to the rear wheel (5) of the bicycle, characterized in that the drive device (1) also comprises a chain tensioner (6) (4) or belt comprising a fixing support (7) to the housing (3), a clamping roller (8) pivotally mounted on the support (7) so as to exert a clamping force on the chain (4) or belt. Drive device according to claim 1, wherein the fixing bracket (7) has two spaced apart fixing lugs (9) for fixing to the housing (3). Drive device according to claim 2, in which the tensioner (6) comprises a pivot pin (10) carrying a pivoting arm (11) on which the clamping roller (8) is mounted via a roller pin (12) , a clamping spring being integrated into the pivot pin (10), so that the clamping force exerted by the clamping roller (8) comes from the spiral spring. Drive device according to claim 2, in which the fixing lugs (9) comprise oblong fixing holes (15) oriented at different angles. Drive device according to claim 3, in which the pivot axis (10) is in the central position of the tensioner (6), between the fixing lugs (9) and the clamping roller (8). Drive device according to claim 3, in which the fixing lugs (9) and the pivot pin (10) are arranged on either side of the fixing support (7), the roller pin (12 ) cooperating with a guide slot (13) of the roller arranged between the fixing lugs (8) and the pivot axis (10). Drive device according to claim 6, in which the guide slot (13) of the roller forms an arc of a circle whose radius corresponds to the distance between the pivot axis (10) and the slot. Tensioner for a drive device (1) for an electrically assisted bicycle according to any one of claims 1 to 7. Electrically assisted bicycle comprising a drive device (1) according to any one of claims 1 to 7.