DESCRIPTION

The present invention refers to a device for operating a regenerative braking in electrical propelled scooter.

In the last years, the electrical propelled scooter have been subjected to an always increasing diffusion due to the zero emissions produced, to the minimal maintenance required and to the low operative costs.

Moreover, it can be easily understood how technical solution allowing to improve the performances thereof, in particular in terms of endurance and reliability, are desirable.

To this end, electrical scooters uses a system allowing to switch the electric motor so that it operates it as an electric generator when the scooter is not accelerating. In this way, not only the batteries supplying the motor can be recharged, but it is also possible to exploit the braking action connected to the use of the motor as a generator.

Then, such function, called regenerative braking, allows to improve the scooter performances, regenerating the more energy is possible which would be otherwise dissipated. One of the main problem associated to the use of regenerative braking systems in the electrical scooters, is connected to the activation of the system thereof when the motor is not in a propulsive phase.

Normally, in electrical scooters regenerative braking is activating when the accelerator is released, such as is shown in the Japanese patent JP 11257478 A. In particular, this could take place by means of a speed or negative torque control loop.

Nevertheless, it is not always desirable that the regenerative braking is automatically operated upon releasing the accelerator, since such action also provides a strong deceleration of the scooter and, accordingly it can be preferable to provide an activation control for the regenerative braking.

To this purpose, the patent application WO 2003 078199 discloses the implementation of a operation control of the regenerative brake according to various embodiments. In a first one, it is possible to rotate the accelerator according to two rotation senses, in a first case providing positive torque, in the second case operating the regenerative braking. In this way, the regenerative brake will be operated only when desired by the driver. Nevertheless, the use of the accelerator according to such method is little practical and, above all hardly intuitive for a driver used to drive traditional motorcycles. In addition, the braking action of the regenerative braking is not coordinated to the mechanical brake in any way and, therefore, the driver should decide which brake to use. It can be easily understood that, in particular for a person used to drive traditional scooters, it is not spontaneous to use the accelerator hand grip for braking, moreover requiring a complex movement of the hand and of the wrist. Therefore, actually the regenerative braking is never used in association with the mechanical braking.

Accordingly, the lack of coordination between regenerative braking and mechanical braking involves an higher wear of the braking system, in particular of the pads, and an objective limit to the capacity of energy regeneration during the braking phase of the vehicle. Then, a second embodiment of such control system uses the brake lever, operating the regenerative braking every time this is pushed. Nevertheless, in this case, the regenerative braking effect is not adjusted in any way by the user, thus providing quite a rough braking. Then, it is also suggested to use a pressure transducer, allowing to provide a signal proportional to the pressure detected by the transducer. Nevertheless, the patent application does not indicate how such transducer should be placed. Moreover, this solution does not allow to precisely coordinate it with the mechanical braking action of the scooter. Hence, the technical problem underlying the present invention is to provide an adjusting system of the regenerative braking of an electric scooter allowing to overcome the drawbacks mentioned above with reference to the known art. Such problem is solved by the device for operating the regenerative braking in electrical propelled scooter according to claim 1 and by the method according to claim 5.

Secondary features of the present invention are defined in the corresponding dependent claims.

The present invention provides several relevant advantages. The main advantage lies in that the device according to the present invention allows to coordinate the regenerative braking action with the mechanical one, using a practical activation system, intuitive and easily operable by the driver. In this way, the regenerative braking can be exploited at best, maximally decreasing the wear of the mechanical braking system of the scooter. Moreover, the device according to the present invention allows to obtain a perfect coordination between the mechanical braking and regenerative braking, thus making the effect of the latter particularly smooth. Other advantages, features and the operation modes of the present invention will be made apparent from the following detailed description of some embodiments thereof, given by way of a non-limiting example. Reference will be made to the figures of the encloses drawings, wherein:

Figure 1 is a block diagram showing the operation of a device for operating the regenerative braking in electrical propelled scooter according to the present invention;

Figure 2 is a block diagram showing the operation of the device for operating the regenerative braking according to a second embodiment;

Figure 3 is an exploded perspective view showing the components of the device of Figure 1;

Figure 4 is a top view schematically showing the operation of the device of

Figure 3; Figures 5A and 5B are a rear perspective view and a partial exploded view of the motor and of the rear wheel assembly of a scooter comprising the device according to the present invention; and

Figure 6 is a perspective exploded view of the device of Figure 2. With reference to Figure 1, a block diagram summarizing the operation of a device for operating the regenerative braking in electrical propelled scooter according to the present invention is shown.

Incidentally, the term scooter will mean that motorcycle category having the characteristic "step-through" shape, i.e. that can be crossed in the lowered portion between saddle and the front shield. Such vehicles are normally two- wheeled but, in some cases, three-wheeled and, the same inventive concepts that will be disclosed in the following could be applied also to this kind of vehicles.

In general, an electric scooter comprises an electric motor M, a control unit CU of the motor, i.e. the motor drive. The control unit CU is therefore connected to the accelerator control 3, to a battery pack BP and, obviously, to the motor itself.

According to a preferred embodiment, the control unit CU and the electric motor M are housed within a single motor assembly 1, shown in deeper detail in figures 5A and 5B, within which also houses the components of a mechanical brake 5, as will be seen in detail in the following.

In addition, connected to the motor assembly 1, a wheel, rim and tyre assembly 4 is provided, onto which operates both the electric motor, and the mechanical brake. Opposite to scooters according to the known art, the control unit CU is also connected to a mechanical brake control 20, e.g. realized by an operation lever, shown in Figures 3 and 4.

In detail, according to a first embodiment, the device according to the present invention comprises means for detecting a mechanical braking, formed in the present embodiment by a micro-switch 21, generating a braking signal S ₆ following the operation of the mechanical brake, in particular of the lever 20. The detecting means 21 are then associated to the control unit CU which therefore, as previously indicated and contrarily to the scooters according to the known art, is also connected to the mechanical brake control, by means of the micro-switch 21. As previously mentioned, in addition of being directed to operate and control the motor for propelling the vehicle, the control unit CU also provides the possibility of switching the operation of the motor so as it operates as an electric generator, i.e. activating the regenerative braking system. Such activation can be also performed analogously to known scooters, i.e. by means 5 of a torque control or by means of a suitable control.

Then, in addition or as an alternative, the device according to the present invention provides that, following the reception of a braking signal S ₆ , generated by the micro-switch when the brake control is operated, the control unit CU switches the operation of the electric motor M to electric generator. In io this way, an electric tension will be obtained for recharging the battery pack BP and, at the same time, an electromagnetic braking torque will be generated that, obviously, will be transmitted to the wheel, rim, tyre assembly 4, thus slowing down the vehicle. In this way, the operation of the mechanical brake control will generate the

/5 simultaneous mechanical and electromechanical braking action, thus allowing to obtain a lower wear of the mechanical braking system, the braking capacity being the same.

In other words, by means of the use of the regenerative braking, the action provided on the operation lever of the mechanical brake being the same, a

20 stronger brake than the scooters according to the known art will be obtained. In practice, it will be sufficient to push less the brake lever for obtaining the same braking action of the traditional scooters.

Moreover, advantageously the driver should not vary in any way the driving method of the vehicle but he/she will simply notice a stronger brake than the

2s traditional scooters. The advantages connected to the use of the device according to the present invention are therefore well evident, allowing a lower use of the mechanical braking system, and therefore a lower wear thereof, in particular of the pads. In addition, such advantages do not entail any additional driving difficulty for the driver, contrarily to the activation systems of known regenerative brakes. Then, with reference to Figures 3 and 4, it is shown in detail the use of the device according to the present invention in a electric scooter. In particular, the micro-switch 21 is placed at a supporting portion 22 of an operation lever 20 of an arm 26 of the scooter handlebar. In this way, the micro-switch 21 can generate the braking signal S ₆ following the rotation of the operation lever 20, as shown in Figure 4. Therefore, the rotation of the lever 20 will simultaneously operate the braking system, e.g. by means of the cable 23 housed in a suitable sheath 24, and operates a braking pump 51, shown in figure 5B, and the control unit CU, by means of the transmission of the signal S ₆ through the cable 25.

Therefore, it can be noticed how such embodiment is particularly simple and economic.

Alternatively, in Figure 2 a second embodiment of the device according to the present invention is shown. Such embodiment will be described only with reference to the aspect differing from the previously described embodiment. Moreover, for the common element to both embodiments the same referral numbers will be used.

As it can be noticed by the block diagram of Figure 2, in the present embodiment the motor assembly 1 further comprises a pressure sensor 55 connected to the hydraulic circuit of the scooter braking system. In this case, as shown in Figures 5B and 6, the pressure sensor 55 is connected to a high pressure duct 54 per operating the mechanical brake 5, that in the present example is formed by the disk 52 and by the respective calliper 53. The pressure sensor 55 is connected so as to detect the pressure increase in the liquid within the high pressure duct 54 occurring upon a breaking action. More precisely, the pressure of the liquid within the high pressure duct 54 is increased upon the operation of the braking pump 51 activated on rotation of the lever 20, connected by means of the cable 23, as previously shown. As a consequence, in the present embodiment, the detecting means are realized by means of the pressure sensor which, once the pressure increases, generates the braking signal S ₆ , that is then transmitted to the control unit CU. In this case, differently from the previously embodiment, it will be possible to define a variable braking control signal S ₆ , in particular proportional to the pressure increase of the liquid within said high pressure duct 54 occurring upon braking. In this way, it can be provided that the control unit switches the electric motor so as to produce an electromagnetic braking torque proportional itself to the pressure increase in the duct 54. Therefore, this solution is particularly advantageous since it allows, in addition to the previously shown advantages, to have a regenerative braking optimally coordinated to the mechanical braking and at same time maximizing the recovered energy during the vehicle braking.

Instead, if the scooter is accelerating, i.e. the vehicle has a real speed lower than the target speed set by the accelerator, the operation of the micro-switch or of the pressure sensor will decrease the accelerating torque of settable parameter. This parameter could be set such that at most the motor torque could be nullified or eventually could be variably defined, according to the pressure detected within the braking system. Therefore, if the driver simultaneously accelerates and brakes, the scooter will accelerate with a lower torque. Apart improving the efficiency, this makes the scooter more easily drivable at low speeds.

In addition, the relationship between pressure increase within the duct 54 and the amount of the regenerative braking, can be varied according to the use requirements, e.g. in the case the scooter is used for transport services, and according to the different driving behaviour.

The present invention has hereto been described with reference to preferred embodiments thereof. It is understood that there could be other embodiments referable to the same inventive kernel, all falling within the protective scope of the claims set forth hereinafter.