Star-shaped wheeled motor vehicle for stairs

Abstract

The invention relates to a motor vehicle with a structure comprising at least one ground connection (16), each ground connection comprising a hub with a central rotation axis (20); a plurality of wheels (22) distributed around said axis; a plurality of arms (24) distributed angularly around said axis, each arm connecting one of the wheels to the hub; an electric motor; the vehicle is remarkable in that each arm comprises a pressure sensor (34) on said arm, each pressure sensor being configured to detect pressure from one of the wheels (22) via the arm (24) associated with said pressure sensor (34); the electric motor being configured to drive the wheels (22) when at least two pressure sensors (34) detect pressure, and configured to brake the wheels (22) when a single pressure sensor (34) detects pressure. Figure to be published with the abstract: Fig. 2

Description

Title of the invention: Star-shaped wheeled motor vehicle for stairs

[0001] The invention relates to the crossing of stairs by a vehicle, in particular by a wheelchair and / or by a robot. The invention relates more specifically to a motor vehicle with wheels arranged in a star shape for crossing stairs.

[0002] When a motor vehicle having wheels arranged in a star shape encounters a staircase, the advancement of the front wheel is blocked by the riser, thus allowing the front wheel to pivot around the step, which allows the vehicle to climb the staircase.

[0003] On the other hand, when descending the stairs, the front wheel cannot be blocked by the step, because only the void is presented at the level of the vehicle when it descends. It is therefore necessary to manually use brakes arranged on the vehicle to be able to control its descent. The use of these brakes is restrictive to operate, which makes it difficult to steer the vehicle. The same problem can be encountered in an urban environment, for example when the presence of a sidewalk must be managed by the vehicle.

[0004] Document CN106892014 discloses an obstacle-clearing robot, and in particular a spiral staircase. The obstacle-clearing robot comprises a central platform, a front chassis and a rear chassis each pivotally connected to the central platform. Each chassis has an axle, each side of which is equipped with a hub receiving three wheels arranged in a star shape. The front chassis is connected to the central chassis using a vertical axis pivot connection, while the rear chassis is connected to the central chassis using a vertical axis pivot connection and a longitudinal axis pivot connection. These last two connections are mounted on an L-shaped hinge support. The rear hinge shaft structure is a double-joint structure, so that when the left and right wheel sets are located at different heights, the left and right axles can touch the ground at the same time.It is therefore difficult to guarantee the stability of the vehicle when it has to descend one or more steps, especially when the vehicle is required to descend a quarter-turn staircase.

[0005] The invention aims to address at least one of the problems or drawbacks encountered in the prior art. In particular, the invention aims to propose a motor vehicle with wheels arranged in a star pattern, the descent of which down a staircase can be controlled.

[0006] For this purpose, the invention relates to a motor vehicle with a structure comprising at least one ground connection, each ground connection comprising a hub with a central axis of rotation; a plurality of wheels distributed around the central axis of rotation; a plurality of arms distributed angularly around the central axis of rotation, each arm connecting one of the wheels to the hub; an electric motor for driving the wheels in motion; the vehicle is remarkable in that each arm comprises a pressure sensor on said arm, each pressure sensor being configured to detect pressure from one of the wheels via the arm associated with said pressure sensor; the electric motor being configured to drive the wheels when at least two pressure sensors detect pressure, and configured to brake the wheels when a single pressure sensor detects pressure.

[0007] As will be understood from reading the definition which has just been given, the invention relates to an electrically powered motor vehicle where the arms connecting the wheels of one or more ground connections of the vehicle have been modified to include a support sensor.

[0008] When a wheel of a ground connection rests on a surface, for example on the ground or on a riser of a staircase, the support sensor of the arm associated with the wheel is activated. However, when a wheel of a ground connection is not resting on any surface, which can happen when the wheel faces a void when descending a staircase, the support sensor associated with the wheel is not activated.

[0009] The arrangement of the support sensors of the vehicle according to the invention, that is to say on each arm each connecting a wheel of a ground connection, means that it is necessary to have at least two activated support sensors so that the electric motor can start the wheels of said ground connection. In this case, there are therefore at least two wheels resting on a surface. Similarly, the activation of only one support sensor will cause the electric motor of the vehicle according to the invention to brake the wheels, or even block them. When only one support sensor is activated, this means that there is only one wheel of the ground connection resting on a surface. Therefore, the other wheels of the ground connection are not resting, and can for example be suspended in the void, in the case where a staircase must be descended.

[0010] This arrangement is therefore advantageous because it allows the electric motor to brake the ground connection wheel which remains in contact with a surface, for example the ground or a riser of a staircase, which makes it possible to guarantee the stability of the motor vehicle when descending a staircase and also to control its descent.

[0011] Furthermore, a motor vehicle equipped with this particular structure as defined in the present invention does not require the presence of a brake for descending stairs or a sidewalk, which therefore makes it easier for the user to drive it.

[0012] Advantageously, the electric motor is a servomotor adapted to be in a driving configuration or a braking configuration, and when at least two support sensors detect a support, the servomotor is in the driving configuration and when a single support sensor detects a support, the servomotor is in the braking configuration.

[0013] Advantageously, the electric motor is a servomotor with a main transmission shaft and a pinion arranged around said main transmission shaft, the electric motor further comprising a first braking system arranged around said main transmission shaft and intended to brake the pinion and when a single support sensor detects a support, said servomotor is configured to actuate the first braking system.

[0014] For example, the servomotor is configured to also operate as an electric current generator when a single pressure sensor detects pressure.

[0015] Advantageously, each wheel is connected at a first end of an arm around a secondary axis of rotation and the electric motor is a servomotor coupled to a set of gears configured to rotate the wheels around said secondary axis of rotation; the servomotor comprises a main transmission shaft and a pinion arranged around said main transmission shaft; the hub comprises an outer face and an inner face, and the set of gears comprises a first crown arranged on said inner face and has external teeth in contact with the pinion of the servomotor and internal teeth with a sun gear and a set of satellites, said set of satellites being in contact with both the internal teeth of the first crown and the sun gear, the sun gear being connected by means of a secondary transmission shaft to a second crown arranged on said outer face,the second crown having external teeth in contact with at least one gear assembled around a secondary rotation axis, the set of gears further comprising a second braking system arranged on the side of the outer face around the secondary transmission shaft and intended to brake the second crown, and when a single support sensor detects support, said servomotor is configured to actuate the second braking system.

[0016] Advantageously, each wheel is connected at a first end of an arm around a secondary rotation axis, and at least one of the wheels comprises a third braking system mounted at said wheel and intended to brake said secondary rotation axis and when a single support sensor detects support, the electric motor is configured to actuate the third braking system.

[0017] Preferably, the third braking system is a disc brake.

[0018] Advantageously, at least one of the wheels comprises a fourth system of braking mounted at said wheel and intended to brake said wheel, and when a single support sensor detects support, the electric motor is configured to actuate the fourth braking system.

[0019] Preferably, the fourth braking system is a drum brake.

[0020] Advantageously, the structure comprises a front part with a front end and the front part comprises a first ground connection and a second ground connection arranged at the same level as the first ground connection relative to the front end, the hub of the first ground connection being connected to the hub of the second ground connection at the central axis of rotation.

[0021] Advantageously, each support sensor shows a movement of at most 5° relative to the main axis of the corresponding arm, more preferably at most 4°.

[0022] For example, at least one or each support sensor is a spring-loaded electrical contact.

[0023] For example, said motor vehicle is a wheelchair or an autonomous robot.

[0024] The invention will be well understood and other aspects and advantages will appear clearly on reading the following description given with reference to the appended figures in which:

[0025] [Fig-1] [Fig.l] shows a motor vehicle according to the invention on a staircase turning.

[0026] [Fig.2] [Fig.2] shows a ground connection of a motor vehicle according to the invention where two wheels are resting on the ground.

[0027] [Fig.3] [Fig.3] is a close-up view of [Fig.2] at the central axis of rotation.

[0028] [Fig.4] [Fig.4] shows a ground connection of a motor vehicle according to the invention where only one wheel is resting on the ground.

[0029] [Fig.5] [Fig.5] shows a mechanical transmission device including a first system used in the motor vehicle according to the invention.

[0030] [Fig.6] [Fig.6] is a close-up view of a mechanical transmission device used in the motor vehicle according to the invention.

[0031] In the following description, the term "comprise" is synonymous with "include" and is not limiting in that it allows for the presence of other steps in the method or other elements in the sealing frame or vehicle to which it relates. It is understood that the term "comprise" includes the terms "consist of".

[0032] Similarly, the terms "lower", "upper", "high" and "low" will be understood according to their usual definition, in which the terms "lower" and "low" indicate a greater proximity to the ground in the vertical direction than the terms "upper" and "high" respectively.

[0033] In the present description, the term "longitudinal" and the term "transverse" are used according to the vehicle reference, in the mounting configuration. The term "longitudinal" corresponds to the main direction of movement of the vehicle. The term "transverse" corresponds to a direction perpendicular to the main direction of movement of the vehicle. The term "front" refers to the main direction of movement of the vehicle. The term "rear" refers to the opposite of the front of the vehicle.

[0034] Throughout the description, the different figures use the same reference signs to designate identical or similar entities.

[0035] [Fig. 1] represents a motor vehicle 10 according to the invention. The motor vehicle 10 climbs a turning staircase 12; in this case a spiral staircase 12, also called a spiral staircase insofar as its steps describe a helicoid.

[0036] The motor vehicle 10 comprises a structure 14, with at least one ground connection 16. Each ground connection 16 comprises a hub 18 with a central axis of rotation 20 (visible in [Fig. 2]). Around the central axis of rotation 20, there are a plurality of wheels 22, for example at least two wheels 22, more preferably at least three wheels 22. A motor vehicle with wheels arranged in a star shape, and therefore in which the structure comprises at least one, preferably at least two ground connections with three wheels each, generally facilitates the transport of loads and is a considerable asset when it comes to crossing one or more steps. The wheels 22 are connected to the hub 18 by means of arms 24 (visible in [Fig. 2]). Each ground connection 16 also comprises an electric motor 26 (visible in FIGS. 5 and 6) to drive the wheels 22 in motion.

[0037] As shown in [Fig.l], the motor vehicle may be a wheelchair 28. The wheelchair 28 comprises a seat 30 mounted on the structure 14. The seat 30 can accommodate a passenger 32. It has a seat, a backrest, and optionally means for holding (not shown) the passenger 32.

[0038] The motor vehicle may alternatively be an autonomous robot (not shown), intended to transport goods.

[0039] According to the invention, the motor vehicle 10 is remarkable in that each arm 24 comprises a support sensor 34 on said arm 24. Each support sensor 34 is configured to detect a support of one of the wheels 22 via the arm 24 associated with said support sensor 34. The support of one of the wheels 22 which is detected is the support of said wheel 22 on a surface, for example the ground or the surface of a riser of a staircase.

[0040] Still according to the invention, the electric motor 26 is configured to drive the wheels 22 when at least two support sensors 34 detect support and also configured to brake the wheels 22 when only one support sensor 34 detects a press.

[0041] As a plurality of wheels 22 is present, for example at least two wheels 22, more preferably at least three wheels 22, there is therefore a number of arms 24 corresponding to the number of wheels 22 and a number of support sensors 34 corresponding to the number of arms 24. In the preferred example of the invention, where a ground connection 16 comprises three wheels 22, there are therefore on each ground connection, three arms 24 connecting each of the wheels 22 to the hub 18 and each ground connection therefore comprises a first support sensor 302, a second support sensor 304 and a third support sensor 306.

[0042] Thus, when a wheel 22 of a ground connection bears on a surface, for example on the ground or on a riser of a staircase, the support sensor 34 of the arm 24 associated with said wheel 22 detects a support and is therefore activated. This configuration is visible in [Fig. 2] and in the close-up view in [Fig. 3], where in the example of a motor vehicle with wheels arranged in a star pattern, a first support sensor 302 and a third support sensor 306 both detect a support on the ground as shown diagrammatically by the “star” symbol in [Fig. 3], while the second support sensor 304 does not detect a support, which is shown diagrammatically in [Fig. 3] by the “cross” symbol. The overall mass of the ground connection, and more generally of the motor vehicle, creates a rotation around the central axis of rotation 20, and makes, as shown diagrammatically by the arrows in [Fig.2], lower the entire ground connection 16 while the arms associated with the first support sensor 302 and the third support sensor 306 rise and bear on the corresponding support sensors, as shown diagrammatically by the “star” symbol in [Fig. 3]. As two support sensors detect a support, the electric motor of the ground connection of the motor vehicle according to the invention is configured to drive the wheels.

[0043] On the other hand, when a wheel 22 faces the void when descending a staircase, the support sensor associated with the arm connecting this wheel 22 does not detect any support and is therefore not activated. This is shown diagrammatically in [Fig. 4], where in the example of a motor vehicle with wheels arranged in a star, only the first support sensor 302 detects a support, indicated with the “star” symbol, because the corresponding wheel is on the surface of the step, while the second support sensor 304 associated with the arm connecting an upwardly directed wheel and the third support sensor 306 associated with the arm connecting a wheel facing the void do not detect any support, indicated in [Fig. 4] with the “cross” symbol. As in this case there is only one support sensor which detects a support, the electric motor of the ground connection of the motor vehicle according to the invention is configured to brake the wheels.

[0044] As shown in [Fig. 3], the support sensors 34 can have a movement of at most 5° relative to the main axis of the corresponding arm 24, preference of at most 4°.

[0045] An example of a support sensor 34 is a spring electrical contact. In the event of support, the spring of said spring electrical contact will compress due to the gravitational force which will act on the rest of the structure of the motor vehicle and therefore on each arm. When the spring compresses, the electrical contact can be made and therefore the spring electrical contact is thus activated. When the wheel connected by the arm associated with said spring electrical contact is not resting on a surface, the spring remains or returns to the rest state, and thus prevents the electrical contact from being made. This makes the spring electrical contact inactive.

[0046] The structure 14 advantageously comprises a front part with a front end and the front part comprises a left ground connection, and a right ground connection, respectively a first ground connection and a second ground connection.

[0047] The first ground connection and the second ground connection are arranged at the same level relative to the front end and the hubs of each ground connection are connected to each other at the central axis of rotation. Therefore, in the case of the descent of a turning staircase 12, when the first ground connection is braked because one of the wheels 22 is facing the void and there is therefore only one support sensor which detects a support, the second ground connection is always in motion due to the greater availability of surface which ensures that at least two wheels are in support and that therefore at least two support sensors detect a support, which makes it possible to descend by turning the motor vehicle. Indeed, there is rotation of the arms connecting the wheels around the central axis of rotation of the ground connection which is not in motion, thus allowing the pivoting of the wheels.

[0048] The electric motor 26 may be a servomotor adapted to be in a driving configuration or a braking configuration, and when at least two support sensors 34 detect a support, for example a first support sensor 302 and a second support sensor 304, the servomotor is in the driving configuration and when a single support sensor 34 detects a support, for example in the case where only the first support sensor 302 detects a support while the second support sensor 304 and the third support sensor 306 do not detect a support, the servomotor is in the braking configuration.

[0049] In this configuration where the electric motor 26 is a servomotor, the activation of only one support sensor 34 will cause the electric motor 26 of the motor vehicle according to the invention to brake the wheels 22 because the electrical power supply to the servomotor is stopped. Stopping the servomotor thus makes it possible to obtain the desired effect and thus guarantee the stability of the motor vehicle and the control of the descent of a staircase and / or a sidewalk.

[0050] The electric motor 26 may be a servomotor with a transmission shaft main 36. A pinion 38, i.e. a toothed wheel which meshes with the teeth of another toothed wheel, for example a first crown 46, is arranged around the main transmission shaft 36.

[0051] As shown in [Fig. 5], the electric motor 26 may further comprise a first braking system 40 arranged around the main transmission shaft 36. The first braking system 40 is intended to brake the pinion 38 and is activated by the servomotor when a single support sensor 34 detects a support. For example, the first braking system 40 is a disc brake.

[0052] The servomotor can be configured to also operate as an electric current generator when a single pressure sensor 34 detects pressure, which makes it possible to recover energy and thus recharge the electric motor.

[0053] The electric motor may be a servomotor coupled to a gear set configured to rotate the wheels 22 about a secondary rotation axis 42. The gear set is for example an epicyclic train which is a mechanical transmission device.

[0054] Thus, the gear assembly may comprise a first crown 46 arranged on the inner face 44 of the hub of the ground connection. The first crown 46 has an external toothing 48 and an internal toothing 50. The external toothing 48 is in contact with the pinion 38 of the servomotor and the internal toothing 50 is in contact with a set of satellites 52, themselves in contact with a sun gear 54. The number of satellites 52 corresponds to the number of wheels 22 of the ground connection. Indeed, a satellite is a gear wheel whose axis is mobile and rotates with the wheel which drives it.

[0055] Thus, as shown in [Fig. 6], in the example of a motor vehicle with wheels arranged in a star pattern, three satellites 52 are present. The satellites 52 are therefore in contact with the sun gear 54, arranged centrally with respect to the first crown 46 and connected by means of a secondary transmission shaft 56 to a second crown 58 arranged on the outer face (not visible) of the hub of the ground connection. The second crown 58 has an external toothing 60 in contact with at least one gear 62 assembled around a secondary rotation axis 42.

[0056] The motor vehicle is configured so that when descending a staircase, when a single support sensor detects support, thanks to the braking system and the set of gears, the wheel associated with said support sensor is held against the riser opposite said wheel. Said riser is vertically at the level of the wheel. To do this, said wheel remains stationary relative to the riser or moves back substantially; while the associated arm tilts forward. This aspect improves the stability of the motor vehicle; and therefore the safety of descending the staircase.

[0057] The gear assembly may thus further comprise a second braking system (not shown) arranged on the outer face side around the secondary transmission shaft 56. The second braking system is intended to brake the second ring gear 58 and is activated by the servomotor when a single support sensor 34 detects support. For example, the second braking system is a disc brake. The second braking system makes it possible to block the movement of the second ring gear 58 when only a single support sensor of an arm is activated. In this way, the wheels 22 of the ground connection lock, making it possible to stabilize the motor vehicle.

[0058] Since each wheel 22 rotates about a secondary axis of rotation 42, a third braking system (not shown) may be mounted at the wheel so as to brake the corresponding secondary axis of rotation 42. For example, the third braking system is a disc brake.

[0059] The use of a fourth braking system mounted at the wheels may also be envisaged. For example, the fourth braking system is a drum brake.

Claims

Claims

1. Motor vehicle (10) with a structure (14) comprising at least one ground connection (16), each ground connection (16) comprising a hub (18) with a central axis of rotation (20); a plurality of wheels (22) distributed around the central axis of rotation (20); a plurality of arms (24) angularly distributed around the central axis of rotation (20), each arm (24) connecting one of the wheels (22) to the hub (18); an electric motor (26) for driving the wheels (22) in motion; the vehicle is characterized in that each arm (24) comprises a support sensor (34) on said arm, each support sensor (34) being configured to detect a support of one of the wheels (22) via the arm (24) associated with said support sensor (34); the electric motor (26) being configured to drive the wheels (22) when at least two support sensors (34) detect support, and configured to brake the wheels (22) when a single support sensor (34) detects support.

2. Motor vehicle (10) according to claim 1, characterized in that the electric motor (26) is a servomotor adapted to be in a driving configuration or a braking configuration, and when at least two support sensors (34) detect a support, the servomotor is in the driving configuration and when a single support sensor (34) detects a support, the servomotor is in the braking configuration.

3. Motor vehicle (10) according to claim 1 or 2, characterized in that the electric motor (26) is a servomotor with a main transmission shaft (36) and a pinion (38) arranged around said main transmission shaft (36), the electric motor (26) further comprising a first braking system (40) arranged around said main transmission shaft (36) and intended to brake the pinion (38) and when a single support sensor (34) detects a support, said servomotor is configured to actuate the first braking system (40).

4. Motor vehicle (10) according to claim 2 or 3, characterized in that the servomotor is configured to also operate as an electric current generator when a single support sensor (34) detects support.

5. Motor vehicle (10) according to one of claims 1 to 4, characterized in that each wheel (22) is connected at a first end of an arm (24) around a secondary axis of rotation (42) and the electric motor (26) is a servomotor coupled to a gear assembly configured to rotate the wheels (22) about said secondary rotation axis (42); the servomotor comprises a main transmission shaft (36) and a pinion (38) arranged around said main transmission shaft (36); the hub (18) comprises an outer face and an inner face (44), and the gear assembly comprises a first crown (46) arranged on said inner face (44) and has external teeth (48) in contact with the pinion (38) of the servomotor and internal teeth (50) with a sun gear (54) and a set of satellites (52), said set of satellites (52) being in contact with both the internal teeth (50) of the first crown and the sun gear (54), the sun gear (54) being connected by means of a secondary transmission shaft (56) to a second crown (58) arranged on said outer face,the second crown (58) having external teeth (60) in contact with at least one gear (62) assembled around a secondary rotation axis (42), the set of gears further comprising a second braking system arranged on the side of the outer face around the secondary transmission shaft (56) and intended to brake the second crown (58), and when a single support sensor (34) detects support, said servomotor is configured to actuate the second braking system.,

6. Motor vehicle (10) according to one of claims 1 to 5, characterized in that each wheel (22) is connected at a first end of an arm (24) around a secondary axis of rotation (42), and in that at least one of the wheels (22) comprises a third braking system mounted at said wheel (22) and intended to brake said secondary axis of rotation (42) and when a single support sensor (34) detects support, the electric motor (26) is configured to actuate the third braking system; preferably, the third braking system is a disc brake.

7. Motor vehicle (10) according to one of claims 1 to 6, characterized in that at least one of the wheels (22) comprises a fourth braking system mounted at said wheel (22) and intended to brake said wheel (22), and when a single support sensor (34) detects support, the electric motor (26) is configured to actuate the fourth braking system; preferably, the fourth braking system is a drum brake.

8. Motor vehicle (10) according to one of claims 1 to 7, ca- characterized in that the structure (14) comprises a front portion with a front end and in that the front portion comprises a first ground connection and a second ground connection arranged at the same level as the first ground connection relative to the front end, the hubs of the first ground connection being connected to the hub of the second ground connection at the central axis of rotation.

9. Motor vehicle (10) according to one of claims 1 to 8, characterized in that each support sensor (34) shows a deflection of at most 5° relative to the main axis of the corresponding arm (24) and / or in that at least one support sensor (34) is a spring-loaded electrical contact.

10. Motor vehicle (10) according to one of claims 1 to 9, characterized in that said motor vehicle (10) is a wheelchair (28) or an autonomous robot.

Images