A bicycle with two rear wheels, in particular a pedal -assisted, multi-functional cargo bicycle, also configurable as an autonomous vehicle

Abstract

A bicycle has two rear wheels (RW) with independent suspension pivoting arms (11 ) and a transmission system (18) which includes an intermediate transmission shaft (19), which takes motion from the pedal crank-motor unit via a front transmission chain (20) and transmits it to the two rear wheels (RW) via two rear transmission chains (23). The intermediate shaft (19) serves both as a transmission shaft and as a shaft for the rotating support of the two pivoting arms (11 ). The sprockets (25) which receive the movement from the rear transmission chains (23) are mounted on the hubs (H) of the two rear wheels (RW), inside the two rear wheels (RW), with the interposition of respective free wheels (R2), which, seen from the side inside the two rear wheels (RW) have opposite free rotation directions. The bicycle has a rear luggage compartment (LK) carried by the frame (2) which is configurable for the transport of goods, either to receive one or more child seats or for the transport of a pet, or even for the transport of any type of operator instrument or tool (W) that can be moved between an inoperative position inside the luggage compartment (L) and an operational raised position. The vehicle is also configurable as an autonomous vehicle.

Description

[0001] A bicycle with two rear wheels, in particular a pedal -assisted, multifunctional cargo bicycle, also configurable as an autonomous vehicle

[0002] Field of the invention

[0003] The present invention regards a bicycle with two rear wheels, in particular a pedal-assisted, multi-functional cargo bicycle, also configurable as an autonomous vehicle.

[0004] The invention more specifically regards a bicycle with two rear wheels, of the type comprising:

[0005] - a frame including a saddle tube, a front steering tube and a lower support for a pedal crank-motor unit,

[0006] - a pedal crank-motor unit including a shaft rotatably mounted within said unit,

[0007] - an electric motor forming part of said pedal crank-motor unit, configured to assist the rotation of the shaft of the pedal crank,

[0008] - a steering shaft rotatably mounted in the steering tube and operatively connected to a front fork carrying a front wheel,

[0009] - a pair of pivoting arms, pivotally mounted, so that they can swing independently of each other, on a portion of the frame extending rearwardly from the lower support of the pedal crank-motor unit about an axis directed transversely with respect to a longitudinal direction of the bicycle,

[0010] - two rear wheels having the respective wheel hubs rotatably supported by rear portions of said pivoting arms,

[0011] - two suspension devices respectively associated with the two pivoting arms and operationally interposed between the two pivoting arms and the frame,

[0012] - a transmission system for transmitting, to the two rear wheels, a rotation of the shaft of the pedal cranks in the direction corresponding to the bicycle forward motion, wherein the transmission system includes:

[0013] - an intermediate transmission shaft, rotatably mounted on the frame around said transverse pivoting axis of the two longitudinal arms, - a front transmission chain, connecting a first sprocket of said pedal crank unit with a second sprocket mounted on said intermediate transmission shaft, and

[0014] - two rear transmission chains connecting two third sprockets mounted on said intermediate transmission shaft with respective fourth sprockets associated with the hubs of the two rear wheels,

[0015] - wherein each of said arms is in the form of a frame with a fork portion including two arms which rotatably support, with their rear ends, a respective rear wheel arranged between the two arms of the fork.

[0016] Prior art

[0017] A vehicle having the characteristics indicated above is described and illustrated in the international patent application WO 2023 / 007331 by the same Applicant (corresponding to the Italian application IT 2021 0002 0297).

[0018] The Applicant has long been conducting studies and experiments aimed at developing and perfecting vehicles of the type indicated above intended for the most varied uses. In addition to the international patent application indicated above, the different solutions proposed over time by the Applicant have also formed the subject of international patent applications WO 2018 / 138594, WO 2020 / 026082 and the international patent application PCT / IB2023 / 051367 still secret at the date of this application. Further solutions in this field are known from US 8 672 075 B1 , JP 3 61 4901 B2 and JP 20000 335468 A.

[0019] The objectives that the Applicant generally intends to achieve in the field of vehicles of the type indicated above are multiple. The growing success of pedal-assisted bicycles has paved the way for a massive diffusion of this means of transport.

[0020] The Applicant's choice to propose a bicycle configuration with two rear wheels is first and foremost due to the desire to drastically increase the level of safety of the vehicle during use and - at the same time - to the desire to make the bicycle much easier to use for the user.

[0021] On the other hand, the bicycle solutions with two rear wheels that have been proposed by others in the past suffer from considerable drawbacks due to the complexity and weight of the structure, the poor stability on bends and the consequent limits to the speed that the vehicle can reach while maintaining safe conditions. Consequently, all previous solutions proposed in this field are complex, heavy, inefficient and also excessively expensive.

[0022] The challenge that the Applicant has, therefore, proposed to face is that of being able to create a vehicle of the type indicated above that is characterized by extreme construction simplicity, low weight, and a very low production cost, all without compromising the possibility of obtaining high characteristics from the point of view of vehicle performance and safety.

[0023] A specific problem within these objectives is to provide two driving rear wheels with completely independent suspensions controlled in such a way as to allow the obtaining of a "differential effect", i.e. a different rotation speed of the two rear wheels on bends, with a solution that is nevertheless simple, light and inexpensive.

[0024] When you then want to apply all the aforesaid concepts to a cargotype bicycle, further problems arise regarding the possibility of providing a large luggage compartment and a low center of gravity without involving a significant increase in the dimensions of the bicycle and without compromising the safety characteristics stability of the bicycle when riding.

[0025] Finally, the Applicant has also addressed the problem of creating a cargo-type bicycle that is multi-functional during use, as it can be reconfigured easily and quickly for different applications.

[0026] In conclusion, the need is felt for further improvements with reference to all the technical problems that have been exposed above.

[0027] Object of the invention

[0028] The aim of the present invention is to create a bicycle with two rear wheels of the type indicated above which solves all the problems described above in a simple and efficient way.

[0029] Summary of the invention

[0030] In view of achieving the aforesaid objects, the present invention relates to a bicycle having the characteristics disclosed at the beginning of this description and further characterized in that: - the aforesaid intermediate transmission shaft is rotatably supported near its ends by the frame of the bicycle,

[0031] - the aforesaid second sprocket driven by the front transmission chain is mounted on said intermediate transmission shaft with the interposition of a front freewheel, which transmits the movement of the front transmission chain to the intermediate transmission shaft only in the direction corresponding to the bicycle forward motion,

[0032] - the aforesaid third sprockets for driving the two rear transmission chains are rigidly connected to the aforesaid intermediate transmission shaft,

[0033] - the frames constituting the two pivoting arms each have two front longitudinal portions parallel to, and spaced apart from, each other, which are freely rotatably mounted on a corresponding side portion of the intermediate transmission shaft, so that the aforesaid intermediate transmission shaft also serves as a shaft for the pivotal support of the two pivoting arms, and in that the aforesaid fourth sprockets, which are driven by the two rear transmission chains, are mounted on the hubs of the respective rear wheels with the interposition of two respective rear freewheels, each of which is configured to transmit the movement of the respective rear transmission chain to the respective wheel hub only in the direction corresponding to the bicycle forward motion.

[0034] Thanks to the configuration described above, the bicycle according to the invention achieves a series of important advantages.

[0035] Firstly, the two rear wheels of the bicycle are both driving wheels supported by totally independent suspensions. At the same time, thanks to the provision of the two free wheels associated with the two hubs of the rear wheels, the obtaining of a "differential" effect, i.e. the possibility for the two rear wheels to rotate at different speeds when traveling around a curve, is obtained with an extremely simple and light structure, but at the same time functional and reliable. This translates into a high level of driving stability of the vehicle, even at the maximum speed allowed for a bicycle with pedal assistance (25 km / h), to the advantage of both the comfort and safety of the user. Obviously the differential effect is also applicable to speed EPAC-type bicycles with pedal assistance up to 45 km / h and to ride-on vehicles or more generally to autonomous robots with three or four wheels without speed limits.

[0036] Another important advantage deriving from the bicycle configuration - subject of the present invention - consists in the fact that it allows the provision of a rear luggage compartment of relatively high capacity and with a very low bottom compared to the ground, thanks to the possibility of exploiting the space between the two rear wheels. To this end, the bicycle frame includes a rear cage portion configured to define a luggage compartment, which can be set up according to different configurations, to adapt the bicycle according to the invention to a multiplicity of different applications.

[0037] A first typical application is that of a cargo bicycle, wherein the rear body is used for the transport of goods. A second application involves the arrangement, inside the compartment, of two child seats, which can also be placed facing each other. A further possible application involves using the compartment to transport a pet or to accommodate any type of instrument or tool, for example, movable between a lowered position stored inside the compartment and a raised position for use of the tool or instrument.

[0038] According to another aspect, the bicycle according to the invention may also be used as an autonomous vehicle, for example, to transport goods or tools or robotic arms in dangerous areas, via remote control. In this case it is envisaged to associate the steering tube with an actuator system (typically an electric motor), which can be moved between an inoperative condition and an operative condition, wherein the actuator is able to control the rotation of the steering shaft. The aforesaid actuation system is controlled by an electronic controller on board the vehicle which also controls the electric traction motor with which the vehicle is equipped. In one example, the on-board electronic controller is associated with a communication module configured to communicate with a communication module of a remote control station. Alternatively, the on-board electronic controller may be programmed according to a predetermined program to drive the vehicle along a predetermined path. Furthermore, in accordance with the technology known in the field of autonomous vehicles, in the case of this application as an autonomous vehicle, the bicycle according to the TRANSLATION (RULE 12.3) 16 JUL 2024 invention is associated with one or more sensors configured to detect the environment external to the vehicle and to communicate the relevant information to the electronic controller of the vehicle. These sensors may, for example, be made up of drones, one or more video cameras, or even a

[0039] 5 single video camera that can be orientated along two mutually orthogonal axes by means of a so-called "gimbal" type system, with multiple joints controlled by respective electric motors.

[0040] An additional electric traction motor may also be provided associated with the front wheel of the bicycle, which can be activated for

[0041] 10 movement of the vehicle in reverse.

[0042] In order to drastically reduce the manufacturing costs of the bicycle, the use of a frame made of square-section tubes, preferably made of high- strength steel or light alloy, rigidly connected to each other, for example, by welding, is envisaged.

[0043] 15 Again with the aim of further reducing manufacturing costs, the wheels of the vehicle, and in particular the two rear wheels, are preferably made in compliance with the disclosures of the co-pending Italian patent application IT 10 2023 000013947 of 04.07.2023, still secret as of the date of this application.

[0044] 20

[0045] Detailed description of the invention

[0046] Further characteristics and advantages of the invention will become apparent from the description that follows with reference to the attached drawings, provided purely by way of non-limiting example, wherein:

[0047] 25 - Figure 1 is a perspective view of a first embodiment of the bicycle according to the invention, with the body panels removed, to clearly show the frame and mechanical parts of the vehicle,

[0048] - Figures 2-4 are a side view, a plan view and a rear view of the bicycle in Figure 1 ,

[0049] 30 - Figure 5 is a cross-sectional view along the line V-V of Figure 2,

[0050] - Figure 6 illustrates a detail of Figure 5 on an enlarged scale,

[0051] - Figure 7 is a perspective view illustrating the bicycle frame of Figure 1 ,

[0052] - Figure 8 is a perspective view illustrating the frame of Figure 7

[0053] 35 completed with the bicycle transmission system, - Figures 9, 10 are side views corresponding to Figures 7, 8,

[0054] - Figure 11 is a perspective view of the bicycle of Figure 1 completed with the body panels that define the luggage compartment for use as a cargo bike,

[0055] - Figure 12 is a side view of the bicycle in the configuration of Figure 11 ,

[0056] - Figure 13 is a view corresponding to that of Figure 5 with reference to a second embodiment, wherein the two rear wheels of the vehicle are further apart from each other,

[0057] - Figure 14 illustrates a detail of Figure 13 on an enlarged scale,

[0058] - Figure 15 is a partial perspective view of the bicycle, in the case of a variant which envisages an electric motor associated with the front wheel to implement a movement of the vehicle in reverse,

[0059] - Figure 16 illustrates a variant wherein the bicycle according to the invention is set up with two child seats, arranged facing each other,

[0060] - Figure 17 is a further perspective view of a variant wherein the bicycle is used to transport a pet,

[0061] - Figure 18 is a side view of a steering assembly of the bicycle according to the invention in a variant configured for use as an autonomous vehicle,

[0062] - Figure 19 is a cross-sectional view of the steering assembly of Figure 18,

[0063] - Figures 20, 21 illustrate a detail of the actuation assembly of the steering, respectively, in an inoperative condition and in an operating condition,

[0064] - Figure 22 illustrates a block diagram of the bicycle control system according to the invention in the case of application as an autonomous vehicle,

[0065] - Figure 23 is a side view illustrating a variant of Figure 18,

[0066] - Figure 24 is a perspective view of the bicycle according to the invention in an embodiment that can be used as an autonomous vehicle and set up for the transport of any instrument or tool,

[0067] - Figures 25, 26 illustrate a perspective view of the bicycle of Figure 24, respectively, in a condition wherein the instrument or tool is lowered into a storage position inside the luggage compartment and in a condition wherein the instrument or tool is raised above the luggage compartment, for its use,

[0068] - Figure 27 is a perspective view of a further variant of cargo bicycle according to the invention, with a different configuration of the frame of the luggage compartment,

[0069] - Figure 28 illustrates the bicycle of Figure 27 used to transport a pet,

[0070] - Figure 29 illustrates a variant wherein the bicycle according to the invention is equipped with two child seats, both arranged in the direction of travel,

[0071] - Figure 30 shows a further variant, wherein the rear frame is configured for the transport of a standing passenger, and

[0072] - Figure 31 illustrates a further variant.

[0073] In the drawings of the different variants of the invention, corresponding parts are indicated with the same reference numbers. In the drawings, numeral 1 indicates - in its entirety - a bicycle having two parallel and spaced apart rear wheels RW and a single front wheel FW. However, the possibility of providing a front wheel assembly with two twin wheels is not excluded.

[0074] The bicycle 1 comprises a frame, indicated - in its entirety - by 2, which in the preferred example is made up of quadrangular section tubes, for example, of high-strength steel or light alloy, rigidly connected to each other (for example welded).

[0075] In the illustrated example, the frame 2 includes a saddle tube 3, a steering tube 4 and a lower support 5 carrying the crankset of the bicycle.

[0076] In the illustrated example, the lower support 5 is connected to the lower end of the saddle tube 3 and to the lower end of a diagonal tube 6 whose upper end is connected to the saddle tube 4.

[0077] A steering shaft (not visible in Figure 1 ) is rotatably mounted within the steering tube 4, in a per se known manner, which, also in a per se known manner, has an upper end rigidly connected to a handlebar 7 and a lower end rigidly connected to a front fork 8 that rotatably supports the front wheel FW.

[0078] Also in a conventional manner, a saddle support tube 9 bearing a saddle 10 is mounted at an adjustable height in the upper end of the saddle tube 3. As can be seen in Figures 1 , 2, in the illustrated example, the bicycle frame 2 does not include an upper horizontal tube to directly connect the saddle tube 3 to the steering tube 4. This is made possible in that the square section tubes constituting the saddle tube 3, the lower support 5 and the diagonal tube 6, are sized to achieve adequate rigidity of the frame 2, without the need to provide an upper horizontal tube.

[0079] The two rear wheels RW are carried by two pivoting arms 11 (see Figure 2 and Figures 7, 8), mounted articulated, so that they can pivot independently of each other, on a rear portion of the frame 2, extending behind the lower support 5 of the frame, around the same axis 12, directed transversely with respect to the longitudinal direction of the bicycle.

[0080] With reference to Figures 7, 8, in the illustrated example, the rear part of the frame 2, which supports the two arms 11 in a pivoting manner, is made up of three longitudinal arms 13A, placed side-by-side, which extend longitudinally behind the support 5. At their rear ends, the two side arms 13A extend into two side arms 13B which diverge from each other and which terminate with two rear end portions 13C, visible in detail in Figure 6. A central arm 13A extends into a central arm 13B terminating in a rear end portion 13D (Figure 6)

[0081] Returning to Figure 1 , the two rear wheels RW have respective hubs which are rotatably supported (in the way that will be illustrated in detail below) by the rear ends of the two pivoting arms 11 .

[0082] The bicycle 1 also comprises two suspension devices 14 (typically two spring-shock absorber assemblies of any known type) operationally interposed between the frame 2 of the bicycle and the two pivoting arms 11.

[0083] Thanks to this arrangement, the two rear wheels RW are supported by the vehicle frame by means of two suspensions totally independent of each other, each of which is made up of a respective pivoting arm 11 and a respective suspension device 14.

[0084] In the preferred embodiment, respective brake calipers, of any known type, are also associated with the rear ends of the two pivoting arms 11 , suitable for cooperating with brake discs 15 associated with the two rear wheels. Figure 8 of the attached drawings clearly shows the pedal crankmotor unit 16 with which the bicycle according to the invention is equipped.

[0085] The pedal crank-motor unit 16 includes a shaft of the pedal cranks (not visible) rotatably mounted within the unit and having ends protruding from the unit 16 to which two pedal cranks 17 are connected.

[0086] The motor 16 is an electric motor of any type suitable for assisting the rotation of the pedal crank shaft.

[0087] In a per se known manner, the electric motor 16 is associated with an electronic controller, configured to regulate the degree of intervention of the electric motor on the basis of the indications provided by the user via a man-machine interface of any known type, arranged on the handlebar 7 (not illustrated in the drawings).

[0088] With particular reference to Figures 5, 8 and 10, the bicycle according to the invention is equipped with a transmission system, indicated - in its entirety - with 18, to transmit the rotation of the pedal crank shaft to the hubs of the two rear wheels RW.

[0089] The transmission system 18 comprises an intermediate transmission shaft 19, supported in a rotatable manner near its ends by the bicycle frame 2 around the same transverse axis 12 on which the arms 11 carrying the rear wheels are pivotally mounted.

[0090] The transmission system 18 comprises a front transmission chain 20 that connects a first sprocket 21 (Figure 5) of the pedal crank assembly with a second sprocket 22, mounted on the intermediate transmission shaft 19.

[0091] The transmission system 18 further comprises two rear transmission chains 23 which connect two third sprockets 24 with corresponding fourth sprockets 25, associated with the hubs H of the two rear wheels RW.

[0092] In the preferred embodiment, the transmission shaft 19 acts both as an intermediate transmission shaft, to transmit the rotation of the pedal crank assembly to the two rear driving wheels and as a shaft to support the pivoting movement of the two arms 11 carrying the rear wheels RW.

[0093] With reference again to the preferred embodiment, the two pivoting arms 11 are each made in the form of a frame with a fork portion including two arms 110 that support in rotation with their rear ends a respective rear wheel RW arranged between them.

[0094] The frame constituting each pivoting arm 11 has two front longitudinal portions 111 , parallel and spaced apart from each other, which are mounted freely rotatable on a corresponding side portion of the intermediate transmission shaft 19 (see Figures 5, 6).

[0095] With reference again in particular to Figure 6, in the illustrated example, the two front longitudinal portions 111 of each pivoting arm 11 protrude at the front from a crosspiece portion 112, from which the two arms 110 of the fork portion extend at the back, which supports a respective rear wheel RW.

[0096] As indicated above, in the preferred embodiment, the intermediate transmission shaft 19 acts both as a transmission shaft to transmit the rotation of the pedal crank assembly to the two rear wheels RW, and as a shaft for the pivoting support of the two pivoting arms 11 .

[0097] A further important detail of the bicycle according to the invention relates to the arrangement of the free wheels designed to allow the rotation of the pedal crank assembly to be transmitted to the rear driving wheels RW only in the direction corresponding to the forward movement of the bicycle.

[0098] In the embodiment illustrated here, a first free wheel R1 (Figure 6) is interposed between the aforesaid sprocket 22, controlled by the front transmission chain 20, and a bushing rigidly mounted on the intermediate transmission shaft 19. The free wheel R1 is configured to transmit the rotation of the pedal crank assembly to the intermediate transmission shaft 19 only in the direction corresponding to the advancement of the bicycle.

[0099] According to the invention, two further sprockets R2 are operationally interposed between the fourth sprockets 25 and the hubs H of the two rear wheels RW, inside the sprockets 25.

[0100] The structure and configuration of the free wheels R1 , R2 may be of any known type. However, it is important to note that, according to the invention, the two rear transmission chains 23 each extend between the two arms 110 of the fork defined by the respective pivoting arm 11 , and are furthermore both arranged in the internal space between the two rear wheels RW. Accordingly, the two sprockets 25 which are driven by the two rear transmission chains 23 are both arranged inside the two rear wheels RW of the bicycle. Consequently, the free wheels arranged inside the sprockets 25, each operationally interposed between the respective sprockets 25 and the respective wheel hub H, must be configured in such a way as to transmit the motion of the respective chain 23 to the hub H only in the direction corresponding to the forward movement of the bicycle and not in the opposite direction. Therefore, the two rear free wheels R2 are configured, when viewed from the side inside the rear wheels, with opposite free rotation directions (one left-handed and the other right- handed).

[0101] Thanks to this characteristic, the two rear wheels RW of the bicycle are free to rotate at different speeds when the bicycle goes around a bend, which allows a sort of "differential" effect to be obtained in an extremely simple and efficient way.

[0102] With reference to the example of the embodiment illustrated in Figure 6, in this embodiment, the intermediate transmission shaft 19 has its ends rotatably mounted (via rolling bearings 130) on the rear portions 13C of the frame. The transmission shaft 19 is also rotatably supported, by means of a sliding bushing, by a central rear portion 13C of the frame.

[0103] The front longitudinal portions 111 of the two pivoting arms 11 are rotatably mounted, by means of bushings made of material with a low friction coefficient, on the intermediate transmission shaft 19, which thus performs the function of supporting the pivoting movement of the two arms 11 . At the same time, the two aforesaid third sprockets 24, which must transmit the rotation of the intermediate transmission shaft 19 to the rear transmission chains 23, are rigidly mounted on the transmission shaft 19 by means of respective bushings (see Figure 6).

[0104] Referring again to Figure 7, in the illustrated example, the frame 2 of the vehicle comprises a rear cage portion 200 which defines the luggage compartment. In the specific example illustrated, the rear portion 200 of the frame has two upper horizontal longitudinal beams 201 that extend rearwards starting from the upper end of the saddle tube 3, to which they are connected via converging arms 202. The rear cage portion 200 also comprises two vertical uprights 203 which connect the front ends of the upper longitudinal beams 201 with the rear side ends 13C, which support the swinging arms 11 in rotation.

[0105] Also visible in Figures 7-10 are the attachments 140, 141 arranged, respectively, on the vertical uprights 203 and on the pivoting arms 11 , for mounting the suspension devices 14.

[0106] With reference again to Figures 1 , 2, reference B indicates a battery pack which is placed in a container mounted behind the saddle tube 3 and which may be extracted laterally after opening a door that may be provided in the bodywork panels of the bicycle. Alternatively, the battery pack B may be removed by sliding it upwards along a guide provided on the saddle tube 3.

[0107] Figure 11 shows an embodiment example of the bicycle of Figure 1 , completed with body panels that define the rear luggage compartment L. Figure 11 refers to an example wherein the sprockets 24 driving the rear transmission chains 23 are mounted on the ends of the intermediate transmission shaft 19, as will be illustrated in detail below, with reference to Figure 14.

[0108] The embodiment example in Figure 11 refers to a variant with a widened track (see in particular Figures 13 and 14). In this case, as indicated above, the two sprockets 24 which transmit motion to the rear transmission chains 23 are rigidly mounted on the intermediate transmission shaft 19 at the two ends of this shaft. Consequently, the rear side portions 13C of the bicycle frame 2 support the intermediate transmission shaft 19 in rotation at more internal portions of the shaft 19. The frame constituting each pivoting arm 11 has the crosspiece 112 from which the two front portions 111 protrude at the front, and are rotatably supported, via bushings, on the intermediate transmission shaft 19. One of the two front portions 111 of each pivoting arm 11 is interposed between the transmission chain 24 and a rear side portion 13C of the frame 2. The other front portion 111 of each pivoting arm 11 is arranged adjacent to the central rear portion 13C of the frame 2.

[0109] Again with reference to the example of Figures 11 -14, in this case 22 indicates a pinion pack associated with a gear change device 220, of a known type, capable of selecting the pinion that meshes with the front transmission chain 20. As is evident, the embodiment of Figures 11 -14, thanks to the larger track, allows the volume of the luggage compartment L to be increased and the lower floor of the luggage compartment to be arranged very close to the ground, which allows the center of gravity of the load to be significantly lowered, resulting in easier driving and greater vehicle stability.

[0110] Figure 15 shows a solution that involves associating an electric motor 30 with the hub of the front wheel, configured to be activated when it is necessary to impart a reverse movement to the vehicle. The in-wheel type motor located in the front wheel hub is usually decoupled from the central motor and comes into operation only for reverse. For applications wherein the EPAC regulation and EPAC speed pedal-assisted bicycles with the imposition of a power and speed limit is not required, the front motor can contribute to the thrust for forward travel.

[0111] Figure 16 shows a setup of the bicycle according to the invention wherein two child seats 31 are provided in the rear luggage compartment L. In the example, the two seats 31 are arranged facing each other.

[0112] Figure 17 shows a setup wherein the compartment L is used for transporting a pet whose access is permitted by a hinged door.

[0113] As indicated above, according to a further aspect, the bicycle according to the invention may also be configured as an autonomous vehicle. In this case, the electronic controller E (Figure 22) of the motorvehicle is configured to receive signals from one or more sensors S (Figure 22) for controlling, with a control in a closed loop position, both the electric traction motor of the vehicle, and an electric motor that controls the rotation of the steering shaft of the bicycle. One or more sensors S are designed to detect the environment outside the vehicle. In the example of Figure 18, a camera 32 mounted on the steering tube 4 is provided.

[0114] With reference to Figures 19-21 , the reference M2 indicates an electric motor for controlling the rotation of the steering shaft, which controls the rotation of a bevel pinion 33 which can be moved axially between an inoperative position (Figure 20) and an operational position (Figure 21 ) wherein this pinion 33 meshes with a conical crown gear 34, rigidly connected with the steering shaft 35, which is rotatably mounted inside the steering tube 4 (Figure 19). Figure 23 illustrates a variant wherein one or two video cameras operating in the visible or infrared are supported in an orientable manner around two mutually orthogonal axes 37, 38, by means of a system of the so-called "GIMBAL" type, with multiple controlled joints by respective electric motors.

[0115] The electronic controller E, on the basis of the signals coming from the sensor (or sensors) S, governs the electric traction motor M1 and the electric steering motor M2, based on a signal of the position of the member controlled by each of these motors, detected by a position sensor P. Both electric motors M1 , M2 are powered by the battery pack B, via an AC / DC converter C.

[0116] Again with reference to Figure 22, the electronic controller M may be associated with a transmission module T, configured to communicate wirelessly with the communication module of a remote control station for remote control of the self-driving vehicle.

[0117] Figures 24-26 refer to a setup wherein any type of tool or instrument is placed inside the luggage compartment L. In the specific example, a setup is illustrated intended to be used by emergency or police forces, for example, in anti-terrorism operations, wherein it is necessary to operate without jeopardizing the lives of those controlling the vehicle. In this case, whatever the instrument or tool is placed in the luggage compartment, it can be expected to be movable between a lowered position, stored inside the compartment L (Figure 25) and a raised position, wherein the tool or instrument may be oriented around a vertical axis 40.

[0118] In a variant, the tool-instrument may be a robotic arm installed in the luggage compartment to carry out dangerous operations, for example, for demining operations. The robotic arm is - in turn - equipped with sensors and cameras suitable for this purpose.

[0119] The operations relating to the configurations described in Figures 24-26 may be managed by a remote operator assisted, for example, by one or more drones. In this sense the vehicle may be ridden at high speed most of the time and remotely managed the last mile for dangerous missions. Figures 27-30 illustrate a variant wherein the rear part of the bicycle frame carrying the luggage compartment L, indicated - in its entirety - with 300, has a lower configuration, with two longitudinal upper beams 301 that extend inclined downwards, starting from the upper end of the saddle tube.

[0120] In this example, the rear wall L1 of the luggage compartment may rotate downwards around its lower side, to form an access ramp, for example, for use by a pet (Figure 28)

[0121] Figure 29 illustrates a configuration with two child seats both oriented in the direction of travel.

[0122] Figure 30 shows a version configured to allow the transportation of a standing passenger, including an additional frame 400 with an upper cross-member 401 graspable by the passenger.

[0123] Figure 31 illustrates a modified version of the bicycle frame, with a front crossbar 500 and a rear crossbar 600 which are used to carry a plurality of J-nozzles (in the example four J-nozzles on each of the two bars 500, 600) for the emission of high pressure fluid jets, to support the vehicle in the air. The nozzles may be connected to a power system of the type that was the subject of the Italian patent application IT 102023000010134 dated 19.05.2023, still secret at the priority date of the present application.

[0124] Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary widely with respect to those described and illustrated purely by way of example, without departing from the scope of the present invention, as defined by the attached claims.

Claims

CLAIMS1. A bicycle with two rear wheels (RW), comprising:- a frame (2) including a saddle tube (3), a front steering tube (4) and a lower support (5) for a pedal crank-motor unit (16),- a pedal crank-motor unit (16) including a shaft (160) rotatably mounted within said unit,- an electric motor (M1 ) forming part of said pedal crank-motor unit (16), configured to assist the rotation of the shaft (160) of the pedal crank,- a steering shaft (35) rotatably mounted in the steering tube (4) and operatively connected to a front fork (8) carrying a front wheel (FW),- a pair of pivoting arms (11 ), pivotally mounted, so that they can swing independently of each other, on a portion (13C) of the frame (2) extending rearwardly to the lower support (5) of the pedal crank-motor unit about a same axis (12) directed transversely with respect to a longitudinal direction of the bicycle,- two rear wheels (RW) having respective wheel hubs (H) rotatably supported by rear portions (110) of said pivoting arms (11 ),- two suspension devices (14) respectively associated with the two pivoting arms (11 ) and operationally interposed between the two pivoting arms (11 ) and the frame (2),- a transmission system (18) for transmitting, to the two rear wheels (RW), a rotation of the shaft of the pedal cranks (160) in the direction corresponding to the bicycle forward motion, wherein the transmission system (18) includes:- an intermediate transmission shaft (19), rotatably mounted on the frame (2) around said transverse axis (12) around which the aforesaid pivoting arms (11 ) are pivotally mounted,- a front transmission chain (20), connecting a first sprocket (21 ) of said pedal crank-motor unit (16) with a second sprocket (22) mounted on said intermediate transmission shaft (19),- two rear transmission chains (23) connecting two third sprockets (24) mounted on said intermediate transmission shaft (19) with corresponding fourth sprockets (25) associated with the hubs (H) of the two rear wheels (RW),- wherein each of said pivoting arms (11 ) is in the form of a frame with a fork portion including two arms (110) which rotatably support, with their rear ends, a respective rear wheel (RW) arranged between the two arms (110) of the fork, the bicycle being characterized in that:- said intermediate transmission shaft (19) is rotatably supported near its ends by the frame (2) of the bicycle,- said second sprocket (22) driven by the front transmission chain (20) is mounted on said intermediate transmission shaft (19) with the interposition of a front freewheel (R1), which transmits the movement of the front transmission chain (20) to the intermediate transmission shaft (19) only in the direction corresponding to the bicycle forward motion,- said third sprockets (24) for driving the two rear transmission chains (23) are rigidly connected to said intermediate transmission shaft (19),- the frames constituting the two pivoting arms (11 ) each have two front longitudinal portions (111 ) parallel to, and spaced apart from each other, which are freely rotatably mounted on a corresponding side portion of the intermediate transmission shaft (19), so that said intermediate transmission shaft (19) also serves as a shaft for the pivotal support of the two pivoting arms (11 ), and in that said fourth sprockets (25), which are driven by the two rear transmission chains (23), are mounted on the hubs (H) of the respective rear wheels (RW) with the interposition of two respective rear freewheels (R2), each of which is configured to transmit the movement of the respective rear transmission chain (23) to the respective wheel hub (H) only in the direction corresponding to the bicycle forward motion.

2. A bicycle according to claim 1 , characterized in that the two rear transmission chains (23) are both arranged within the forks (110) of the two pivoting arms (11 ) and both within the two rear wheels (RW), and the two rear freewheels (R2) are configured, when viewed from the space inside the two rear wheels (RW), with directions of free rotation which are opposite to each other.

3. A bicycle according to claim 1 , characterized in that each of said pivoting arms has a crosspiece portion (112) directed transversely with respect to the longitudinal direction of the bicycle, and in that the two arms (110) constituting the supporting fork of the respective rear wheel (RW) extend rearwardly from said crosspiece portion (112), while the aforesaid two front longitudinal portions, (111 ) which are pivotally mounted on the intermediate transmission shaft (19) extend forwardly from said crosspiece portion (112).

4. A bicycle according to claim 3, characterized in that the frame (2) of the bicycle has two side rear portions (13C) that rotatably support the ends of said intermediate transmission shaft (19) by means of rolling bearings (130), in that the frame (2) of the bicycle comprises a central rear portion (13D) that rotationally supports the central portion of the aforesaid intermediate transmission shaft (19), and in that the aforesaid front portions (111 ) of the frame constituting each pivoting arm (11 ) are spaced apart from each other, and are respectively adjacent to said central rear portion (13D) of the frame (2) and to the respective side rear portion (13C) of the frame, said third sprocket (24) associated with each rear wheel (RW) being rigidly mounted on a portion of the intermediate transmission shaft (19), between the two front portions (111 ) of the respective pivoting arm.

5. A bicycle according to claim 3, characterized in that the aforesaid third sprockets (24), which drive the two rear transmission chains (23), are rigidly connected to the two opposite ends of said intermediate transmission shaft (19), in that the frame (2) of the bicycle has:- two rear side portions (13C) that support in rotation, via rolling bearings (130), the intermediate transmission shaft (19), and- one central rear portion (13D) that rotatably supports a central portion of the intermediate transmission shaft (19), and in that the front portions (111 ) of each pivoting arm (11), which are rotatably mounted on the intermediate transmission shaft (19), are arranged one between a respective third sprocket (24) and a respectiverear side support (13C) of the bicycle frame, and the other adjacent to said rear central portion (13D) of the bicycle frame.

6. A bicycle according to claim 1 , characterized in that an electric motor (30) operable to impart a rearward motion to the bicycle is associated with the front wheel hub.

7. A bicycle according to claim 1 , characterized in that the frame (2) of the bicycle has a rear cage-like portion (200), extending rearwardly from the saddle tube (3), configured to define a rear luggage compartment (L) arranged between the two rear wheels (RW), having a bottom wall arranged below the axis of the rear wheels (RW).

8. A bicycle according to claim 1 , characterized in that it is also equipped with an additional electric motor (M2) for controlling the rotation of the steering shaft (35).

9. A bicycle according to claim 8, characterized in that said electric motor (M2) for controlling the rotation of the steering shaft (35) controls a pinion (33) axially displaceable between an inoperative position and an operative position wherein the pinion (33) engages with a crown gear (34) rigidly connected to the steering shaft (35).

10. A bicycle according to claim 1 , characterized in that it is provided with an electronic controller (E) that controls an electric traction motor (M1 ) and an electric steering control motor (M2) based on signals from one or more sensors (S), operating in the visible and infrared, capable of detecting the environment outside the vehicle.

11. A bicycle according to claim 1 , characterized in that it has a rear luggage compartment (L) configured to receive one or more child seats (31 ) or configured to transport a pet.

12. A bicycle according to claim 1 , characterized in that it has a rear luggage compartment (L) configured to transport an instrument or anoperator tool (W) movable between a lowered position recovered within the luggage compartment (L) and a raised position for use, wherein said instrument or tool (W) can be preferably oriented about a vertical axis (40).

13. A bicycle according to claim 12 characterized in that the rear luggage compartment (L) carries a robotic arm for performing hazardous operations with the aid of cameras, the robotic arm being remotely controllable.

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