WO2010118899A1

WO2010118899A1 - Unicycle, particularly of the stationary type, with improved device for transmission between the pedals and the wheel

Info

Publication number: WO2010118899A1
Application number: PCT/EP2010/051276
Authority: WO
Inventors: Luca Schieppati
Original assignee: Lamiflex S.P.A.
Priority date: 2009-04-17
Filing date: 2010-02-03
Publication date: 2010-10-21
Also published as: IT1394695B1; ITMI20090636A1

Abstract

A unicycle (1), particularly of the stationary type, with improved device for transmission between the pedals and the wheel, comprising a flywheel (2) which is supported rotatably by a main frame (3), which is functionally connected to a saddle (4), to a handlebar (5) and to a pair of pedals (6) which are accommodated inside said flywheel (2) and are associated kinematically therewith by transmission means (7), the transmission means (7) comprising a train of epicyclic gears, which is functionally associated with the pair of pedals (6) and is accommodated and supported inside a gear carrier (32), which is supported rotatably by the main frame (3), the gear carrier (32) having an outer circular profile which is in contact engagement with the internal circular profile of the flywheel (2) for transmission by rolling friction of the driving torque generated by the user as a consequence of the rotation of the pair of pedals (6).

Description

UNICYCLE, PARTICULARLY OF THE STATIONARY TYPE, WITH IMPROVED DEVICE FOR TRANSMISSION BETWEEN THE PEDALS AND THE WHEEL Technical Field The present invention relates to a unicycle, particularly of the stationary type, with an improved device for transmission between the pedals and the wheel. Background Art

Currently the market of sports equipment, particularly equipment dedicated to cycling, offers a wide variety of stationary bicycles, commonly known in the jargon by the trademark Cyclette®, which are suitable to allow the practice of cycling while stationary, without therefore requiring the broad spaces typically needed for the use of road bicycles.

The evolution of stationary bicycles has led to a continuous improvement of this equipment, making it ever more high-performing and sophisticated over time.

Such stationary bicycles are typically composed of a frame provided with an adapted stand, a saddle and a handlebar, and support a flywheel mass, which typically consists of a disk provided with a large moment of inertia, which is functionally connected, by means of an adapted mechanical transmission, to a pair of pedals supported rotatably by said frame.

More precisely, the flywheel mass is arranged below the handlebar, so as to correspond to the front wheel of a road bicycle, and is connected kinematically to the pedals by means of a belt or chain transmission. Such stationary bicycles can be provided with a plurality of accessories, always related to physical activity, such as for example an onboard computer adapted to monitor physical activity by measuring and monitoring values such as the degree of difficulty of the stroke, the rhythm of the stroke, an estimate of the calories burned, the heart rate of the user and other values that are useful to the user for monitoring the execution of the exercise.

In order to act on the intensity of the stroke by simulating for example a change in the grade of the road, stationary bicycles are provided with adapted braking means, which typically act on the flywheel mass for generating a contrast torque in opposition to the driving torque generated by the user.

Such braking means, which can be actuated by way of actuators of the mechanical and magnetic type by acting on an adapted adjustment knob, consist of a shoe which can engage in an adapted track for mechanical and/or magnetic sliding, which is formed directly on the flywheel mass.

Since the mechanical transmission between the pedals and the flywheel mass is typically in constant engagement for simulating continuously the resistance caused by the rolling friction between the wheels of a road bicycle and the road, in case of an emergency, such as for example in case of a physical injury to the user during pedaling, such braking means can be used to stop instantly or almost instantly the flywheel mass and therefore the legs of the user by acting on an appropriately provided emergency button.

In recent years, the continuing quest for ever better functionality and simplicity of stationary bicycles has led to the provision of stationary bicycles whose shape abandons the concept of road bicycles, i.e., a frame that resembles the classic frames of road bicycles in which the front wheel was replaced by the flywheel mass, following instead the concept of a unicycle formed by a large flywheel that is supported rotatably by a main frame where the pedal assembly is accommodated inside the flywheel.

The typical components of a stationary bicycle, such as for example the saddle, the handlebar and the stand, are installed directly on the main frame.

With this configuration, the user directly straddles the flywheel, differently from traditional stationary bicycles, where the flywheel lies outside the pedaling space occupied by the user.

These stationary unicycles, if compared with stationary bicycles of the traditional type, enjoy the great advantage of having a flywheel mass with a much larger diameter than that of stationary bicycles of the traditional type.

This difference, for an equal transmission ratio between the flywheel mass and the pedals, leads to a larger geometric moment of inertia, since the moment of inertia is directly proportional to the square of the distance between the generic infinitesimal mass that constitutes the flywheel mass and the rotation axis of said flywheel mass.

As regards the transmission used for stationary unicycles, currently it is known to use a chain transmission formed by a chain that is wound around a sprocket, which is jointly connected for rotation to the pair of pedals, and around a pinion, which is connected kinematically to the flywheel.

These conventional stationary unicycles are not devoid of drawbacks, which include the fact that the chain transmission used to provide the kinematic connection between the pedals and the flywheel has a particularly low degree of quietness, which is common to all chain transmissions. This drawback is particularly conspicuous if the stationary unicycle is used away from noisy environments such as for example gymnasiums and the like. During use of the unicycle in particularly quiet spaces, such as for example at home, the noise caused by the meshing of the driving ring gear and of the driven pinion with the chain can in fact be particularly unpleasant to the user and to people in the vicinity.

Another drawback of conventional stationary unicycles provided with a chain transmission is that they need periodic maintenance operations for lubrication of said transmission, entailing an inconvenience for the user, particularly if the unicycle is used in private spaces. This inconvenience is due not only to the need to perform these operations in order to ensure correct operation of the transmission but also to the fact that during the lubrication steps part of the lubricant might accidentally drop out of the region of interest, dirtying and/or greasing, for example, the floor and nearby objects as well as the user. Disclosure of the Invention

The aim of the present invention is to provide a unicycle, particularly of the stationary type, with an improved device for transmission between the pedals and the wheel, which makes it possible to practice cycling even indoors, solving the problems of the background art, ensuring a particularly high degree of quietness and minimizing maintenance operations.

Within this aim, an object of the present invention is to provide a unicycle, particularly of the stationary type, with an improved device for transmission between the pedals and the wheel that makes it possible to obtain a transmission ratio between the pedals and the wheel that is particularly adapted for the practice of indoor cycling.

This aim and these and other objects which will become better apparent hereinafter are achieved by a unicycle, particularly of the stationary type, with improved device for transmission between the pedals and the wheel, comprising a flywheel which is supported rotatably by a main frame, which is functionally connected to a saddle, to a handlebar and to a pair of pedals which are accommodated inside said flywheel and are associated kinematically with said flywheel by transmission means, characterized in that said transmission means comprise an epicyclic gear train, which is functionally associated with said pair of pedals and is accommodated and supported inside a gear carrier, which is supported rotatably by said main frame, said gear carrier having an outer circular profile which is in contact engagement with the internal circular profile of said flywheel for transmission by rolling friction of the driving torque generated by the user as a consequence of the rotation of said pair of pedals. Brief description of the drawings Further characteristics and advantages of the present invention will become apparent from the description of a preferred but not exclusive embodiment of a unicycle, particularly of the stationary type, with improved device for transmission between the pedals and the wheel, according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a perspective view of an embodiment of a unicycle, particularly of the stationary type, with improved device for transmission between the pedals and the wheel, according to the invention; Figure 2 is a side elevation view of the unicycle shown in Figure 1;

Figure 3 is a front elevation view of the unicycle shown in Figure 1;

Figure 4 is a sectional view of the unicycle shown in Figure 3, taken along the line IV-IV;

Figure 5 is a sectional view of the unicycle shown in Figure 3, taken along the line V-V;

Figure 6 is a side elevation detail view of the unicycle shown in Figure 1;

Figure 7 is a perspective view of the transmission means of the unicycle shown in Figure 1 ; Figure 8 is a front elevation view of the transmission means shown in

Figure 7;

Figure 9 is a side elevation view of the transmission means shown in Figure 7;

Figure 10 is a sectional view of the transmission means shown in Figure 7, taken along the line X-X. Ways of carrying out the Invention

With reference to the figures, the unicycle, particularly of the stationary type, with improved device for transmission between the pedals and the wheel, generally designated by the reference numeral 1, comprises a flywheel 2, which, as described in greater detail hereinafter, acts as a flywheel mass of the unicycle 1 and is supported rotatably by a main frame 3, which is functionally connected to a saddle 4, to a handlebar 5 and to a pair of pedals 6, substantially of the traditional type, which are accommodated inside the flywheel 2 and are kinematically associated with it by transmission means 7.

The flywheel 2 can consist of a rim 8 on which an external rubber trim 9 is fitted.

The rim 8, which can be made for example of an aluminum alloy such as the Al 6082-T6 alloy, is ring-shaped with an exemplary diameter of approximately half a meter and can have a transverse cross-section equal to a half-circle, in which the chord that delimits said cross-section faces outward and is oriented substantially parallel to the rotation axis 10 of said flywheel 2.

This shape provides, on the outer profile of the rim 8, a cylindrical surface that is particularly adapted to adhere to the external rubber trim 9.

The external rubber trim 9 is also ring-shaped, with a transverse cross-section that is equal to a half-circle in which the chord that delimits the cross-section faces inward and is oriented substantially parallel to the rotation axis 10, with an inside diameter that coincides with the outside diameter of the rim 8.

The external rubber trim 9 can be provided by means of a deposition of rubber which is vulcanized directly on the outer surface of the rim 8 and subsequently profiled.

In order to achieve better adhesion between the external rubber trim 9 and the rim 8, it is possible to provide on the outer surface of said rim a plurality of radial or circumferential grooves, so as to allow the external rubber trim 9 to grip the rim 8 directly upon deposition.

The flywheel 2 is supported rotatably by the main frame 3 by means of a plurality of idle rollers 11, for example four in number, arranged at 90° to each other, contoured on their external profile 12 for engagement with the internal circular profile of the flywheel 2, i.e., with the internal profile of the rim 8.

The idle rollers 11 , which can be made of plastics with a glass fiber reinforcement such as PA66 GF30, are associated rotatably with the main frame 3 and their axes are substantially parallel to the rotation axis 10.

For example, each idle roller 11 is supported rotatably, by means of two single-ball bearings 13, by a supporting shaft 14, which is pivoted to the main frame 3 with an eccentricity for example of approximately half a millimeter with respect to the axis of the supporting shaft 14 in order to recover and adjust the plays between the idle rollers 11 and the flywheel 2, so as to allow smooth and precise rotation of the flywheel 2 with respect to the main frame 3.

As regards the main frame 3, which can be made alternatively of different materials, such as for example carbon fiber, steel and other metals according to the design, styling and commercial requirements of the unicycle 1 , said frame is composed substantially of two lateral shoulders 15 and 16, which can be arranged so as to face each other, with interposition of the flywheel 2 and the transmission means 7 between them.

The lateral shoulders 15 and 16 are substantially shaped like a flat ring with a maximum diameter that is. substantially equal to the inside diameter of the flywheel 2.

The lateral shoulders 15 and 16, which as will be described in greater detail hereinafter have portions 17, 18 and 19 for fixing respectively the saddle 4, the handlebar 5 and the transmission means 7, are jointly connected to each other by means of the idle rollers 11, whose supporting shafts 14 are pivoted at their ends respectively to the lateral shoulder 15 and to the lateral shoulder 16 in the manner described earlier.

Advantageously, the main frame 3 can be integrated with a crescent- shaped covering element 20, which is adapted to cover at least partially the outer surface of the corresponding flywheel 2 at least between the saddle 4 and the handlebar 5, in order to avoid accidental contacts between the user and the flywheel 2 during use of the unicycle 1.

As regards the saddle 4, it can be formed by any cycling saddle provided with a conventional coupling. In order to be able to adjust the position of the saddle 4 with respect to the main frame 2, so that it is ergonomically correct in accordance with the height of the user, means 21 are comprised for adjusting the spatial position of the saddle 4 with respect to the main frame 2.

The adjustment means 21 are composed of a system with guides of the telescopic type, which comprises two guides 22, which are hinged to the saddle 4 by means of a fixing system which is per se known and therefore not described and can be inserted slidingly between two portions 17 that protrude from the lateral shoulders 15 and 16.

The mutual fixing between the guides 22 and the portions 17 can be carried out for example by means of a plurality of nuts and bolts or the like, which can be inserted in appropriately provided slots 23 and 24 provided respectively on the guides 22 and on the portions 17.

As regards the handlebar 5, it can be defined by two horn-shaped elements 25, made for example of carbon fiber or any other material, or by any other conventional handlebar.

The horn-shaped elements 25 can be fixed laterally to the lateral shoulders 15 and 16, and for being able to also adjust the position of the handlebar 5 with respect to the main frame 2, so that it is ergonomically correct according to the height of the user, means 26 are provided for adjusting the spatial position of the handlebar 5 with respect to the main frame 2.

Each horn-shaped element 25 is rigidly connected to a disk 28, for example made of steel, by means of two screws, not shown, and a ring 27, for example, which is also made of steel and is rigidly connected, by means of the screw 30, to a support and adjustment pivot 12, on which a spring is fitted which is preloaded and interposed between the ring 27 and the disk 28.

The support and adjustment pivot 12, which is rigidly connected to the respective shoulder 15 or 16 by means of two screws with a flared head, is partly inserted in the disk 28 for a depth of approximately half a centimeter, and is locked radially by two pins 29 which determine the position of the disk 28 and the pivot 12 to each other.

In order to allow the assembly of the adjustment means 26, covers 31 are provided which can be fixed to the horn-shaped elements 25 and can be removed from them.

According to the invention, the transmission means 7 comprise an epicyclic gear train which is functionally connected to the pair of pedals 6 and is accommodated and supported within a gear carrier 32, which is supported rotatably by the main frame 2 at the two radially recessed portions 19 of the main frame 2 with respect to the rotation axis 10.

Advantageously, the epicyclic gear train can be provided by a first gear 33, which is connected rotatably and coaxially to the gear carrier 32 and is jointly connected for rotation to the central pivot 34 that supports the pair of pedals 6, and by at least one first planet pinion 35, two planet pinions in the specific case in order to avoid having eccentric masses, meshing with the first gear 33 and supported rotatably by the gear carrier 32 for the rotation of the first planet pinion 35 with respect to its own axis and jointly connected for rotation and coaxial with at least one second planet pinion 36, two planet pinions in the specific case in order to avoid having eccentric masses, meshing with a second gear 37, which is coaxial with the first gear 33 and is fixed with respect to the main frame 2 for the rotation of the gear carrier 32 with respect to the axis of the central pivot 34.

More particularly, the gear carrier 32 comprises an external ring 38, which has, on the external circular profile 39, a deposit of vulcanized rubber, which engages by contact the inner circular profile of the flywheel 2 for transmission, by rolling friction, of the driving torque generated by the user as a consequence of the rotation of the pair of pedals 6.

In this manner, once everything has been assembled, there is a preloaded contact between the gear carrier 32 and the flywheel 2 in order to avoid mutual slippage, so as to ensure motion transmission.

The external ring 38 is monolithic with a central hub 47, in which the central pivot 34 is inserted, by means of four supporting spokes 40, two of which also support rotatably the first planet pinions 35 and the second planet pinions 36. In order to make the kinematic system as silent, self-lubricating and lightweight as possible, the gears 33 and 37 can be made of an aluminum alloy, such as for example ERGAL 7075-T6, and the planet pinions can be made of plastics, such as for example PA 66-GF30.

In order to avoid unwanted intrusions of foreign objects between the components of the transmission means 7, such means can be concealed by means of lateral covering elements 45 and 46, which can be integrated in the main frame 2.

In order to be able to generate an adjustable contrast torque to be applied in opposition to the driving torque generated by the user and to be able to stop the rotation of the flywheel 2 and of the pair of pedals 6 if needed, means 41 for braking the gear carrier 32 can be provided.

Advantageously, the braking means 41 can comprise a braking shoe 42, which is supported rotatably by the main frame 2 and can be engaged functionally on a braking surface 43 formed directly on the gear carrier 32 to adjust the resisting torque as a consequence of the action of actuation means 44, which can consist of a step linear actuator, which by being controlled by an appropriately provided control unit adjusts the distance between the braking shoe 42 and the braking surface 43.

The braking shoe 42, which can be made of an aluminum alloy such as AL 6082-T6, is of the magnetic type and the braking surface 43 is provided by a ring of ferromagnetic material that is jointly connected for rotation to the gear carrier 32.

Magnetic braking is therefore achieved by the action of a plurality of permanent magnets with a high magnetization charge, which are accommodated inside the braking shoe 42 and are adapted to generate a contrast torque in opposition to the driving torque generated by the user.

In a possible variation of the braking means 41, the braking of the gear carrier 32 can be carried out not by magnetic effect but by friction caused by the mechanical sliding of the braking shoe 42 on the braking surface 43.

The unicycle 1 described so far might in principle be used on the road as a means of locomotion.

In a possible improvement of the unicycle 1 , if one wishes to use it as a means of locomotion, it can be provided with an auxiliary wheel which is arranged in front of or behind the flywheel 2 and can steer the unicycle by means of adapted lever systems which are functionally connected to the handlebar 5.

If instead the unicycle 1 is to be used as a stationary bicycle, it is provided with a stand 48 that can rest on the ground, is jointly connected to the main frame 2 and is formed on the side opposite the saddle 4 and the handlebar 5 in order to raise the flywheel 2 from the ground and keep it so that its axis of rotation 10 is substantially parallel to the resting plane of the unicycle 1.

Of course, since they have to bear the weight of the user and transfer to the ground all the stresses generated by use of the unicycle 1, the joints between the stand 48 and the lateral shoulders 15 and 16 are suitably reinforced.

The unicycle 1 can be provided with several accessories which are typical of cycling equipment, such as for example an onboard computer which is integrated in the covering element 20 and is capable of performing the typical functions of this sector or water bottle holders which can be fixed for example to the main frame 2.

Operation of the unicycle 1 , particularly of the stationary type, with improved device for transmission between the pedals and the wheel is described hereinafter.

Adjustment of the saddle 4 occurs by loosening the locking nuts of the telescopic system so as to be able to slide the guides 22 out of the portions 17 until the desired position of the saddle 4 is reached.

Subsequently, such locking nuts are tightened onto the corresponding bolts for locking the position of the saddle 4.

The handlebar 5 is adjusted by gripping of the horn-shaped element 25, and, by pulling it outward, the spring is loaded until the pins 29 exit from the respective holes in the support and adjustment pivot 12.

More precisely, the ring 27, being screwed rigidly to the support and adjustment pivot 12, remains motionless and the disk 28, being rigidly screwed to the horn-shaped element 25, loads the spring.

Once the pins have been moved so that they exit, the horn-shaped element 25 is turned until the new desired position is found which corresponds to the successive holes in the support and adjustment pivot 12, and is released until the disk 28 returns to rest completely against the shoulder 15 or 16.

Once the positions of the saddle 4 and of the horn-shaped elements 25 of the handlebar 5 have been adjusted, the user, sitting on the saddle 4, by pushing on the pair of pedals 6, as with a traditional bicycle, generates a driving torque which can be transmitted, by means of the first gear 33, which is jointly connected for rotation to the main pivot 34 of the pair of pedals 6, to the first planet pinions 35, which are turned.

Such pinions, being coupled to the supporting spokes 40 of the gear carrier 32, transmit the driving torque to the second planet pinions 36, which, by meshing with the second gear 37 which is jointly connected to the main frame 2, turn the gear carrier 32 with respect to the axis of the central pivot 34.

By rolling friction, the external ring 38 transmits the driving torque to the flywheel 2, which is turned with respect to its own rotation axis 10. As already noted, the flywheel 2 is supported rotatably by the main frame 3 by means of the idle rollers 11 , which due to the eccentricity of the supporting shaft 14 recover and adjust the plays between the flywheel 2 and the idle rollers 11 , making the stroke smoother and quieter.

During use of the unicycle 1 it is possible to monitor the execution of physical activity by means of the onboard computer and to act on the braking means 41 to adjust the contrast torque applied to the gear carrier 32 and therefore adjust the intensity of the stroke as a function of the needs of the user.

The braking means 41 can be used to block, in case of emergency or need of the user, the gear carrier 32, such as for example in case of injury to the user.

Moreover, the same braking means 41 can be used to block the pair of pedals 6 and thus facilitate the mounting and dismounting of the unicycle 1 by the user. In practice it has been found that the unicycle, particularly of the stationary type, with an improved device for transmission between the pedals and the wheel according to the present invention fully achieves the intended aim and objects, since it makes it possible to practice stationary cycling while limiting to a minimum generating of noise that is unpleasant to the user of the unicycle and to people in the vicinity.

Another advantage of the unicycle according to the present invention is that it does not require complicated maintenance operations, such as for example lubrication of the transmission.

The unicycle, particularly of the stationary type, with improved device for transmission between the pedals and the wheel thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

All the details may further be replaced with other technically equivalent elements. In practice, the materials used, as long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. MI2009A000636 from which this application claims priority are incorporated herein by reference. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A unicycle, particularly of the stationary type, with improved device for transmission between the pedals and the wheel, comprising a flywheel (2) which is supported rotatably by a main frame (3), which is functionally connected to a saddle (4), to a handlebar (5) and to a pair of pedals (6) which are accommodated inside said flywheel (2) and are associated kinematically with said flywheel (2) by transmission means (7), characterized in that said transmission means (7) comprise a train of epicyclic gears, which are functionally connected to said pair of pedals (6) and are accommodated and supported inside a gear carrier (32), which is supported rotatably by said main frame (3), said gear carrier (32) having an outer circular profile which is in contact engagement with the internal circular profile of said flywheel (2) for transmission, by rolling friction, of the driving torque generated by the user as a consequence of the rotation of said pair of pedals (6).

2. The unicycle according to claim 1, characterized in that said epicyclic gear train comprises a first gear (33), which is connected rotatably and coaxially to said gear carrier (32) and is jointly connected for rotation to the central pivot (34) that supports said pair of pedals (6), at least one first planet pinion (35) that meshes with said first gear (33) and is supported rotatably by said gear carrier (32) for the rotation of said first planet pinion (35) with respect to its own axis and is jointly connected for rotation and coaxial to at least one second planet pinion (36), which meshes with a second gear (37) which is coaxial to said first gear (33) and is fixed with respect to said main frame (2) for the rotation of said gear carrier (32) with respect to the axis of said central pivot (34).

3. The unicycle according to claim 1, characterized in that it comprises means (41) for braking said gear carrier (32) to adjust a contrast torque to be applied in opposition to said driving torque generated by said user.

4. The unicycle according to one or more of the preceding claims, characterized in that said braking means (41) comprise a braking shoe (42), which is supported rotatably by said main frame (3) and can functionally engage a braking surface (43) defined by said gear carrier (32) to adjust said contrast torque as a consequence of the action of actuation means (43).

5. The unicycle according to one or more of the preceding claims, characterized in that said flywheel (2) is supported rotatably by said main frame (3) by means of a plurality of idle rollers (11), which are contoured on their external profile (12) for engagement with said inner circular profile of said flywheel (2), said idle rollers (11) being associated rotatably with said main frame (3) and their axes being substantially parallel to the rotation axis (10) of said flywheel (2).

6. The unicycle according to one or more of the preceding claims, characterized in that each one of said idle rollers (11) is supported rotatably by a supporting shaft (14), which is pivoted to said main frame (3) with an eccentricity with respect to the axis of said supporting shaft (14) for recovery and adjustment of plays between said free rollers (11) and said flywheel (2).

7. The unicycle according to one or more of the preceding claims, characterized in that it comprises means (21, 26) for adjusting the spatial position of said saddle (4) and of said handlebar (5) with respect to said main frame (3) in order to adjust the positions of said saddle (4) and of said handlebar (5) with respect to said main frame (3) which are ergonomically correct according to the height of said user.

8. The unicycle according to one or more of the preceding claims, characterized in that it comprises an element (20) for the at least partial covering of the outer surface of said flywheel (2), which can be associated with said main frame (3) correspondingly at least between said saddle (4) and said handlebar (5).

9. The unicycle according to one or more of the preceding claims, characterized in that it comprises a stand (48), which can rest on the ground, is jointly connected to said main frame (3) and is defined on the side opposite said saddle (4) and said handlebar (5) in order to raise said flywheel (2) from the ground and keep said flywheel (2) with said rotation axis (10) substantially parallel to the resting plane of the unicycle (1).