Variable geometry traction device

Abstract

The invention is a traction device for a vehicle, such as a wheel or a track, comprising one or more traction accessories that can change position to transition from a position enabling traction on the ground to a position ensuring traction in or on the surface of a fluid, or even to traction on a slippery surface. The main applications are land vehicles capable of traveling on roads as well as on uneven or muddy terrain and of navigating on or in water, such as a motor vehicle, a boat capable of operating on shallow waters, a submarine, or an aircraft capable of landing on a beach or on the water.

Description

Title of the invention: Variable geometry traction device technical field

[0001] The invention is a vehicle traction device that can adapt to the environment on which or in which it moves, by the use of auxiliary traction accessories such as wings, blades, vanes, anti-slip treads, removable studs and cleats, etc. Previous technique

[0002] CN107962922A of April 27, 2018, by CUI JIE et al., is known, describing a track equipped with a plurality of paddles arranged on the outer end faces of the tracks and which provide traction for an amphibious vehicle in water. These paddles are permanently perpendicular to the outer faces of the tracks, so that they are not well suited to the movement of the vehicle on hard ground and slow the vehicle in their upper part when they encounter water.

[0003] We know of CN108422821 (A) of August 21, 2018 by SUN SHILIANG which describes a similar device and presents the same drawback.

[0004] We know of CN110733305 (A) of January 31, 2020 by WANG XINGBO et al. which describes a blade comprising a plurality of flexible blades ensuring the traction of a vehicle in water, but which is also poorly adapted to the circulation of a vehicle on a hard ground.

[0005] We know of US 10259280 (B 1) of April 16, 2019 by ROE RICHARD DARIN [US] which describes a vehicle equipped with wheels allowing it to roll on a ground, which have on their lateral part paddles to ensure the traction of the vehicle on water, but the efficiency of the drive on water of this device is low.

[0006] CN114619813A of June 14, 2022, from GAO ​​SHENGYUN [CN] is known, describing a four-wheeled amphibious vehicle with paddles that can be periodically deployed and retracted, the switch between a land driving mode and an aquatic driving mode being achieved by rotating the angle of a cam. This vehicle cannot automatically switch to land driving mode upon encountering a solid obstacle, and the paddles cannot all be simultaneously retracted, which poses space constraints.

[0007] We know of WO2007079045A2 of July 12, 2007, from MUNSHAUR TODD [US] and VAN OSDELL STEVEN [US], which describes an amphibious vehicle equipped with floating amphibious traction wheels, the wheels having a number of foldable pockets arranged around the surface of the wheel and oriented in the direction of rotation of the wheel. This vehicle cannot operate in a fluid in reverse, whereas reverse propulsion is the most effective braking method for boats.

[0008] Numerous documents describing variants of the Voith Schneider cycloidal traction system, also known as a cyclorotor, are also known, including BRI 12023023953 (A2) of January 30, 2024, from HOFREITHER KLEMENS [AT] et al., US 1730758 (A) of October 8, 1929, from EDWARD CALDWELL JONATHAN, RU2060203 (Cl) of May 20, 1996, from FEDCHISHIN VIT ALU G [RU], and EP3715249 (A2) of September 30, 2020, from CYCLOTECH GMBH [AT]. None of the devices described in these documents allows operation on hard surfaces.

[0009] Numerous documents describing tire studs and spikes are known. All these elements are inherently rigid to penetrate ice, and when retracted, they either protrude from the tread and are not part of its outer surface, which is therefore discontinuous, or they constitute a hard spot on the tread that impairs road holding and quiet operation. Some deploy or retract under the effect of temperature, but other methods are proposed to achieve this deployment and retraction, such as that proposed by US9278584B2 of March 8, 2016, by BUSHNELL RAYMOND B [US] and LARSON BRADLEY KS [US], which describes a plurality of stud actuation chambers contained within a toroidal shell enclosing an air-filled chamber and having an external radial surface. Technical problem

[0010] The devices described above do not allow a vehicle to switch from a configuration allowing energy-saving quality driving as is permitted with smooth wheels or tracks rolling on a smooth and non-slip surface such as a road or dry path, to another configuration suitable for driving on mud, snow or ice, or even for aquatic traction or aerial traction.

[0011] The problem is complex because the tread must have several possible aspects and therefore include traction accessories which can deploy from their retracted position to their deployed position when necessary to ensure the traction of the vehicle by their pressure on a fluid or on a granular medium such as sand, snow, mud or loose soil, but also retract when they encounter an obstacle such as ground hard enough to damage them.

[0012] They must not disrupt the operation of the tread by an irregularity in its elasticity or additional noise as is the case with studded tires.

[0013] They must also allow, on command of a person or a computer, to move from one position to another in a gradual or abrupt manner, to brake and to operate in reverse in all circumstances, and to extract themselves from the mud and to raise the vehicle above the surface of the water to limit its drag, while being compatible with flexible tires ensuring good road holding.

[0014] Numerous inventors have been searching for a solution for years without success. The two closest documents are the following: - US9278584B2 cited above, which describes stud actuation chambers, but since these are contained within the unequipped strip of the tire, the studs are limited in size and allow only a small part of the applications of the present invention, - and the aforementioned WO2007079045A2 which describes foldable pockets arranged around the surface of the wheel, but these pockets would tear upon encountering certain obstacles instead of closing, and they only work when moving forward. Brief description of the drawings

[0015] The invention will be well understood, and other objects, advantages and features thereof will become more apparent from the reading of the description which follows, which is illustrated by figures 1 to 15.

[0016] [Fig-1] is a perspective view of components of a wheel according to the invention and of an assembled wheel. On the left, we see the traction accessories 21, 22, and 23 and following, which are chevron-shaped blades, and whose position is determined by the secondary shaft 40, which is a ring offset relative to the primary shaft 10, thus driving all the blades downwards. On the right, we see that only blades 24, 25, and 26 are visible, the others remaining enclosed in their housings 210, 220, and 230.

[0017] [Fig. 2] is a perspective and cross-sectional view of the wheel of [Fig. 1], in which The blades are less far from the axis of rotation 10 of the wheel, which has the effect that they are all set back from the unequipped band, and do not limit the elasticity of the wheel allowing it to absorb the shocks of small obstacles.

[0018] [Fig. 3] is also a perspective and cross-sectional view of the wheel of [Fig. 1] and of the [Fig.2], in which the secondary shaft 40 is offset downwards and forwards, which has the effect that the blades located at the front of the wheel give rise, during the rotation of the propulsion wheel, to a force directed more downwards than on the device shown in [Fig.1] where this force is directed backwards.

[0019] [Fig.4] is a perspective view of two IA wheels whose blades 21 22 and following are flat and sliding. These traction accessories are vanes on the left and winter tire stud assemblies on the right. Elastic reminders 31 32 and The following push them in the direction from their retracted to their deployed position. The wheel rolls on hard ground, and the lower traction accessories are in the retracted position, while the upper traction accessories are in the deployed position. If this wheel were rolling on mud or fresh snow, the lower traction accessories would be in the deployed position. This device is particularly well-suited to airless tires.

[0020] [Fig. 5] is a perspective view of two wheels according to the invention, of which the Housings 210 and following traction accessories are fixed only to the band not equipped with wheel IA.

[0021] [Fig.6] is a perspective view of dawns 21 22 and following similar to those represented in [Fig.1], each equipped with a bearing, respectively 211, 221 and following, allowing their position to be determined by cooperation with a concave cam visible in [Fig.7].

[0022] [Fig.7] is a perspective view of the mechanism which determines the position of the blades depending on their position in the rotation cycle of the wheel. Elastic returns not shown push the blades towards their deployed positions, but this movement is limited by the concave cams 401 and / or 402. On the left, the concave cam 402 places them all at an equal distance from the primary shaft 10, while on the right, the concave cam has pivoted by 180 degrees and released the blades in such a way that it is the oblong-shaped cam 401 that allows the blades of the lower part of the wheel to be deployed while those of the upper part are not.

[0023] [Fig.8] is a perspective view of a vehicle equipped with paddle wheels according to figures 1, 2, 3 or 6. It is equipped with 4 wheels according to the invention and in addition at the front of an obstacle crossing aid device according to patent application FR3048404A3 of Franck Guigan [FR] of September 8, 2017.

[0024] [Fig.9] is a perspective view of two mechanical subassemblies of this vehicle. The one on the left is in hard ground driving mode and all the blades are in the retracted position, while the one on the right is in water or in water driving mode and the lower blades are in the deployed position.

[0025] [Fig. 10] is a perspective view of two devices functioning as a wheel but constructed according to the cyclorotor method. The blades are wings which are here in a retracted position (both left and right) to form a complete wheel. A wing 21 pivots relative to the wheel along axis 51, and its inclination is determined by the position of the arm of an element 4 called the synchronizer, which rotates around the shaft 40 called the secondary shaft, to determine sets of possible positions of the blades 21, 22, 23, and subsequent blades. This axis of the main shaft 10, driving the rotation of the wheel, coincides here with that of the shaft 40, driving the rotation of the synchronizer, and all the blades are in a retracted position.

[0026] [Fig. 11] is a perspective view of two identical wheels that differ by the The distance between the hub forming the secondary shaft 40 and the assembly formed by the left side of the wheel and the fenders. On the left, it is moved away from this assembly and the fenders are in the retracted position, while on the right it is moved closer, which increases the circumference of the synchronizer and brings all the fenders into the deployed position. An identical mechanism can be used to deploy and retract any type of traction accessory.

[0027] [Fig. 12] is a perspective view of another implementation of the invention, in Three different configurations are used, with the blades 21, 22, and following blades oriented differently depending on the direction of rotation. Those on the left and right wheels are in a traction position within a fluid, in one or the opposite direction of rotation, while those on the center wheel are in a retracted position. The flexible blades create a homogeneous tread, giving this wheel excellent road handling capabilities.

[0028] [Fig. 13] is a perspective view of a vehicle equipped with wheels 1A1, 1A2 and 1A3 according to [Fig. 12], driving forward on road, then on soft ground and finally in water.

[0029] [Fig. 14] is a perspective view of three AI wheels whose blades 21 22 and The following are tire tread patterns. These traction accessories are: - in the retracted position on the left - a position suitable for low-speed driving - which reduces the surface area of ​​the tread actually in contact with the ground when the traction device is traveling on a flat, hard surface, resulting in significant energy savings and reduced road noise; - in the middle position in the center - a position suitable for high-speed driving - which offers the advantages of good grip, good stability in corners, a short braking distance, and greater driving comfort, but results in higher fuel consumption; - and in the deployed position on the right, which allows driving on snow or mud.

[0030] [Fig. 15] is a perspective view of a caterpillar according to the invention. The blades 21 22 and following are in the deployed position at the bottom, providing traction on soft ground or on or in water, while those at the top are in the retracted position. The elastic return springs are not shown, but two belts 61 and 62 can be seen forcing the vanes located in the upper part of the track IB to move into the retracted position. Description of the invention

[0031] The invention is a traction device for a vehicle such as a wheel IA or a track IB comprising - a plurality of so-called traction accessory elements (21, 22 and following, - and a so-called deployment / retraction mechanism allowing a traction accessory to deploy from a so-called retracted position, in which it is closer vertically to the axis of rotation of said wheel or of that of the roller supporting said track as the case may be, to a so-called deployed position, in which it is further away, and conversely to retract, characterized in that one of said traction accessories: - includes, at least in one of its possible positions, a flexible portion of the outer surface of said tread, - and does not retract under the effect of a force applied to it giving rise to a rotational moment applied to said device, in the two directions of rotation called forward and reverse, if this rotational moment is less in the direction of rotation called forward than a first predetermined threshold, and in the direction of rotation called reverse than a second predetermined threshold, and that all of said traction accessories can be simultaneously in the retracted position, it being specified that the above and below are understood - by tread the outer part of said traction device, including said traction accessories, that is to say the part which comes into contact with the ground when the latter is flat and hard, - by unequipped strip, the part of said tread without said traction accessories, which includes, where applicable, the carcass of said tread, i.e. the framework which ensures its strength and resistance to load, - by deploying and retracting movements of a traction accessory going respectively in the direction from the retracted position to the deployed position and in the opposite direction, - and by cycle the complete sequence during which one of said traction accessories makes a complete revolution of said wheel or said track as the case may be.

[0032] It is also a traction device for a vehicle such as a wheel IA or a track IB comprising - a plurality of so-called traction accessory elements 21, 22 and following, - and a so-called deployment / retraction mechanism allowing a traction accessory to deploy from a so-called retracted position, in which it is closer vertically to the axis of rotation of said wheel or of that of the roller supporting said track as the case may be, to a so-called deployed position, in which it is further away, and conversely to retract, characterized in that said traction accessory is a blade contributing to the traction of the vehicle by its pressure on a fluid or a granular medium, and that all of said traction accessories can be simultaneously in a retracted position.

[0033] It is also a traction device for a vehicle such as an airless tire wheel, consisting of a central hub and an unequipped band connected by multiple elastomer links ensuring the elastic deformability of the tire IA comprising - a plurality of elements called traction accessories 21, 22 and following, - and a mechanism called deployment / retraction allowing a traction accessory to deploy to move from a position called retracted in which it is closer vertically to the axis of rotation of said wheel or to that of the roller supporting said track as the case may be, to a position called deployed in which it is further away, and conversely to retract, characterized in that said traction accessories are placed between said links when they are in the retracted position. Detailed description of the invention

[0034] The principle of the present invention is to equip a track not fitted with a wheel or track with a plurality of traction accessories that can be deployed at the command of a control means to automatically adapt to the medium on which or in which the vehicle is moving. For example, a traction accessory is thus placed in a retracted position when the vehicle is on solid ground such as a road, and in a deployed position when the vehicle is moving either on soft ground such as mud or snow, or on slippery ground such as ice or black ice, or in or on the surface of a fluid. This also makes it possible to travel on irregular surfaces such as uneven ground or shallows and to navigate on rivers or streams considered unnavigable, or even in poorly understood maritime areas.

[0035] In one embodiment, the traction accessory is a traction vane of the vehicle by its pressure on a fluid such as mud, water or air, but it can also be an outgrowth of a tire or a track allowing to drive on a muddy or snowy ground, or in some embodiments a stud or a series of studs allowing not to slip on black ice or ice.

[0036] It is particularly advantageous for the traction device to include an elastic return means 31 allowing the retraction of a traction accessory when an obstacle prevents its deployment during the cycle. This elastic return prevents damage to the traction accessory when it encounters an obstacle or excessively hard ground.

[0037] An important improvement consists of equipping the traction device with a means for adjusting the elastic resistance of this elastic return, so that an operator or a computer can adjust it by means of a control. This makes it possible, for example, to have a smooth tire wheel to save energy when traveling on a dry paved road, but to deploy traction accessories when necessary.

[0038] The traction device can be equipped with traction accessories of several different kinds, such as traction vanes and crampons.

[0039] A traction accessory can also change its nature depending on the extent of its deployment. For example, a protrusion may deploy with a small extension, while a larger extension causes cleats to protrude. To take another example, a blade may deploy perpendicularly to the unequipped strip with a small extension, but tilt forward or backward with a larger extension.

[0040] The present invention is particularly suited to wheels with airless tires. These tires most often consist of a central hub and an unequipped band connected by multiple elastomer links that ensure the tire's elastic deformability. In this case, the traction accessories are advantageously positioned between these links when in the retracted position. It is also suitable for airless tracks made according to the same principle of elastomer links ensuring good track deformability, allowing for high-speed operation.

[0041] The movement of the traction accessory can be arranged so that, when moving forward, it moves backward when transitioning from the deployed to the retracted position, and forward when moving backward. This facilitates its retraction if it encounters an obstacle while moving forward. If the traction accessory is moved by sliding, it is sufficient that the direction of the sliding be inclined relative to the vertical line passing through the same point on the unequipped strip (not shown).

[0042] The geometry of the traction device is advantageously designed such that the effect of a rotational moment applied to said device by a traction accessory, if it is less than a determined threshold, is not sufficient to make it move from its deployed position to its retracted position.

[0043] Those skilled in the art have many means at their disposal to prevent a traction accessory in the deployed position from moving into the retracted position under the effect of a tangential force applied to the unequipped belt, in both directions of rotation, known as forward and reverse. - in the case of sliding, the trajectory is perpendicular to the force - in case of rotation, the tangential force does not give rise to a rotational moment applied to the traction accessory because the force exerted on the deployed part of the traction accessory is aligned with its center of rotation.

[0044] The rotation of the traction accessory caused by a force with a tangential component can also cause it to bump against an obstacle which prevents its retraction.

[0045] The designer can also determine the characteristics of an elastic return to be applied to the traction accessories so that a force applied to one of them is less in the direction of rotation said forward than a predetermined threshold, and in said direction of rotation said reverse than a predetermined threshold which may be different.

[0046] A traction accessory may pass through the unequipped belt as shown in the figures. To maintain the material continuity and sealing of the unequipped belt, or for other reasons, it may also be located inside this belt and deform its outer surface without passing through it, for example by bearing against its inner surface when it passes into the deployed position, or be embedded in this belt in the retracted position without passing through it and move away from it towards the outside of the traction device in the deployed position. These versions are not shown.

[0047] A traction accessory can have all sorts of possible shapes (not shown), such as a flat surface, a portion of a sphere, or a rod or a set of rods, depending on the intended use.

[0048] The travel of a traction accessory can be greater than that which takes it from the retracted position to the deployed position, both towards the inside of the unequipped band to reach a so-called extreme retraction position, and towards the outside to reach a so-called extreme deployment position.

[0049] The assembly consisting of a traction accessory and its deployment / retraction mechanism can, in one of its possible positions, extend beyond the thickness of the unequipped band to be located partly in a volume whose periphery is the inner face of the unequipped band.

[0050] The extreme retraction position may, for example, correspond to all said traction accessories being placed in a position in which they are not rotationally fixed with the traction device.

[0051] The extreme deployment position can for example cause the studs of the traction accessory and / or the unequipped band to come out, in addition to the coming out of conventional protrusions allowing driving on muddy ground.

[0052] The deployment and retraction of the traction accessories can be carried out in many different ways without departing from the scope of the present invention.

[0053] The connection of the traction accessories to the traction device can be achieved by a synchronizer but also by independent mechanical or pneumatic means. or hydraulic, or even by magnets or electromechanical means which can be independent.

[0054] The designer can thus use many known means to easily maintain the sealing of an inflated tire, or prevent foreign bodies from crossing the unequipped band.

[0055] Each traction accessory can be equipped with its own deployment / retraction mechanism, these means being coordinated by a single means, but it is simpler to equip the device with a mechanical means allowing the selection of a set of predetermined positions. In both cases, the means for determining a configuration of the traction accessories is hereinafter referred to as a synchronizer.

[0056] This synchronizer is advantageously a purely mechanical mechanism, excluding any use of hydraulic or pneumatic technologies, to benefit from the simplicity and reliability of such mechanisms, reduced maintenance and low cost, but this is not mandatory.

[0057] This synchronizer can mechanically connect, directly or indirectly, the vehicle with a plurality of traction accessories. Such synchronizers are shown in Figures 1, 2, 3, 6, 7, 10 and 11.

[0058] Different types of synchronizers are proposed which can produce cyclic movements of said traction accessories: - a synchronizer may for example include a secondary shaft 40 parallel to the axis of rotation of the traction device, this shaft being able to be offset from this axis of rotation and rotate with the traction device as shown in figures 1, 2, 3, 10 and 11; - it can also include a cam cooperating with a follower or a pusher, for example one or more fixed cams 401 and 402 as shown in figures 6 and 7.

[0059] A particular cam synchronizer is illustrated by [Fig.5] which shows the combination between two concave cams 401 and 402 which each determine the set of possible positions of the traction accessories, according to two different configurations made available to the user who can thus put into service the cam 402 to drive on a road or the cam 401 to navigate on water or in mud.

[0060] A person skilled in the art can use both concave and convex cores, or assemblies of both types, to modify the position of the traction accessories during the cycle.

[0061] The synchronizer may advantageously deform elastically and / or have flexible parts. This elasticity may also constitute the so-called elastic return mechanism 31 allowing the retraction of said traction accessories when an obstacle opposes their deployment during the cycle.

[0062] In the case where the synchronizer consists of a mechanical assembly comprising a secondary shaft 40 connected directly or indirectly to traction accessories by rigid or flexible links, it may be necessary to provide a specific device to synchronize the rotation of the secondary shaft 40 with that of the primary shaft 10. Those skilled in the art have many known means to achieve this synchronization.

[0063] The synchronizer is advantageously mechanically linked to the vehicle, so that the latter can be used as a reference point to determine the position of a traction accessory within the cycle. The vehicle therefore comprises, in this case, the fixed part of the synchronizer, and optionally a means for modifying the configuration of said synchronizer and a control means for this modification, which can be operated by a person or by a computer. The person or computer in question can be located on the vehicle or outside of it, using, for example, remote control means, without departing from the scope of the present invention.

[0064] An elastic means may be provided so that, when a traction accessory has been placed in its fully retracted, retracted, deployed, or fully deployed position, it remains in equilibrium. In either of these two cases, the synchronizer or another mechanical means may be used to place a traction accessory in one or the other of these equilibrium positions. An advantage of this solution is that it can maintain all traction accessories in a stable position throughout the rotation of the wheel or the entire cycle of a track, without friction between the traction accessory and the unequipped track. In this case, it is recommended to equip the device with several means for changing the equilibrium position of a traction accessory.

[0065] Fixed magnets or electromagnets can, for example, be used to move or hold traction accessories in the retracted position in the upper part of the tread, and other magnets or electromagnets to move the traction accessories into the deployed position on command. These magnets or electromagnets can be located at unique positions along the cycle. Magnets can be moved to be active or inactive or reversed to have opposite effects. A single electromagnet may be sufficient to move the traction accessories from the retracted position to the deployed position or vice versa.

[0066] Depending on the synchronizer configuration, the traction accessories may be, for example: - either all in the retracted position, - or all in the deployed position, - or, which is an advantage of the present invention, those which are in one part of the cycle in the deployed position, and those which are in another part of the cycle in the retracted position.

[0067] Regardless of the type of synchronizer chosen, it is possible to move the traction accessories located at the bottom of the traction device to their deployed position and, conversely, to move those located at the top to their retracted or fully retracted position. This has the advantage of reducing the device's size and, above all, of not offering resistance to the forward movement of a vehicle equipped with a wheel or track according to the invention when it moves on or in water. This distinguishes the device according to the invention from older paddle wheels, the upper part of which could strike waves, thus hindering the boat's progress, and it allows the use of a fully submerged wheel. The device according to the invention thus makes it possible to propel a submarine, a land vehicle, or a boat that becomes a submarine.This also allows the use of wheels according to the invention with existing vehicles undergoing only slight modification, by preventing the traction accessories from striking the wheel arch in the bodywork. This can be achieved by numerous means available to those skilled in the art, such as a stop fixed to the vehicle chassis preventing the deployment of the traction accessories in the upper part of the tread. Such a stop is formed by belts 61 and 62 on the track of the [Fig. 14].

[0068] The operation of the synchronizer makes it possible to determine which part of the cycle the traction accessories are in the deployed position and which part they are in the retracted position, which traction accessories are moved, and what the extent of the deployments considered is.

[0069] In a synchronizer configuration, the traction accessories are in the deployed position in one part of the cycle, and in the retracted position in another part of the cycle.

[0070] In another configuration of the synchronizer, the traction accessories are in the deployed position in an upper part of the tread, and in the retracted position in a lower part of the tread.

[0071] When the device according to the invention is a track, the synchronizer can elastically push the lower traction accessories towards their deployed position. Advantageously, it simultaneously and continuously pushes those at the top towards their retracted position. This can be a simple stop, a rail, a cable, or belts 61 and 62 as shown in [Fig. 14].

[0072] The synchronizer can also, as shown in [Fig. 3], generate a downward force during wheel rotation, which can also allow It's just as easy to pull a vehicle out of mud as it is to push a vehicle moving on water upwards to reduce drag, or even to make it take off and fly. The human operator or the computer controlling the vehicle can vary the direction of the force in real time, for example, from a vertical upward direction to extract a vehicle stuck in the mud, to a more horizontal direction to optimize its resistance to movement in the given environment. When the vehicle is used for underwater navigation, this can be how it determines its position relative to the surface.

[0073] The traction device according to the invention therefore advantageously includes a means of determining which part of the cycle the traction accessories should be in the deployed position and which part they should be in the retracted position.

[0074] A traction accessory may include a portion of the tread. The traction accessories as a whole may also constitute all or almost all of the tread of the device when all the traction accessories are in the retracted position.

[0075] Traction accessories advantageously have an internal structure made of rigid but flexible materials and are easily removable for quick replacement. In the example shown in Figures 12 and 13, in their retracted position they form the tread of the tires and thus their main wear areas, which means that the bulk of the tire can last longer.

[0076] To allow a large number of traction accessories to deploy simultaneously, the deployment of one of them can cause the deployment of another traction accessory, and its retraction can cause the retraction of yet another traction accessory. Those skilled in the art know many ways to achieve this result, whether the objective is to drive a nearby or distant traction accessory.

[0077] It is advantageous to be able to modify the nature of a traction accessory depending on the extent of its deployment. For example, the deployment of a tire tread pattern can, if more pronounced, cause the lugs of that tread pattern to protrude. More generally, the deployment of a traction accessory can thus cause, during part of this deployment movement, the deployment of another traction accessory of the same traction accessory.

[0078] Wide tires or tracks offer the advantages of good grip, good cornering stability, short braking distances, and ride comfort, but result in higher fuel consumption. It is therefore advantageous that the deployment of a traction accessory can increase or decrease the tread area, i.e., the surface effectively in contact with the ground when the traction device rolls on a flat, hard surface.

[0079] In one of its configurations, known as energy saving, the tread area may be less than half its value in another configuration, known as maximum efficiency.

[0080] Figure 14 illustrates three different configurations, obtained by a simple change in the distance of the traction accessories to the wheel's axis of rotation, and shows that the same tire can be used in many different use cases.

[0081] This method of implementation can be combined with others, some of the traction accessories also being able to deploy further to become paddles, or include crampons that deploy from a certain deployment of the traction accessory that includes them.

[0082] The optimal configuration can be controlled by a user, but also in real time by a computer that takes into account the vehicle's speed and trajectory, its load, and the state of the medium on or in which it is moving. The traction device should then advantageously include sensors to evaluate these parameters.

[0083] In the so-called energy saving configuration, the tread surface may not have a positive or negative tread pattern (also called a groove) exceeding 0.5% of the total height of the traction device.

[0084] In this so-called energy-saving configuration, the unequipped strip advantageously comprises one or more continuous or discontinuous rings, each with a width less than 20% of the unequipped strip.

[0085] The possibility of deployment and / or retraction of a traction accessory can be limited by friction, for example by modifying the structure of the contact surfaces during sliding or rotating movement, when subjected to a significant torque resulting from resistance to the vehicle's forward motion. Ball or needle bearings, or equivalent devices, can also be used.

[0086] A wheel can be made up of traction accessories which are cyclorotor wings forming, in their retracted position, a circular tread allowing it to roll on the ground. The synchronizer can be designed so that the wings propel the vehicle only when they move back and forth in the lower part of the tread; a preferred solution is for this traction to occur, as with conventional cyclorotors, when they move from top to bottom and bottom to top. The advantage of these two solutions, which can be combined, is that the wheel, when fully immersed in water, is efficient for most of its cycle. These solutions are shown in Figures 10 and 11.

[0087] The traction accessories are then wings, and they can be deployed in the lower part of the tread and retracted in the rest of the tread, but it is advantageous to use the method applied to cyclorotors. This also makes it possible to change the direction of the thrust provided by the wings without changing the direction of rotation of the device, simply by changing the configuration of the synchronizer. A vehicle equipped with such cyclorotor wheels can thus drive on the ground, propel itself on or through a fluid, or even fly. It also offers the advantage of virtually automatic cleaning of the wings when driving in mud or snow.It is also possible, without departing from the scope of the invention, to vary the geometry of the cyclorotor by increasing the radius of rotation of the wings as well as their surface area, which has a significant effect on the transmissible power and therefore the speed of the vehicle in water or even in air.

[0088] What has just been explained for cyclorotor type wheels also applies to tracks, which can be equipped with wings of the same nature and operate according to the same principles.

[0089] A synchronizer configuration can be provided in which the traction accessories are stored near the axis of rotation of the wheel hub 10 in the hyper-retracted position. In this case, they can remain stationary relative to the rest of the wheel throughout the wheel's rotation. This is one way of eliminating any friction caused by the passage of traction accessories during wheel rotation.

[0090] Figure 11 shows how all the traction accessories can be maintained in their retracted or extended position. The position of all the traction accessories is determined by moving a part of the synchronizer, such as its hub, along the axis of rotation of the wheel.

[0091] This may be suitable, for example, when the traction accessories are studs or sets of studs protruding from the unequipped tread when the ground is icy. This particular configuration can be achieved by causing a suitable deformation of the synchronizer, the hub here also being located on the axis of rotation of the wheel

[0092] When the wheel is driven by means of a shaft connecting a motor to the wheel, it is difficult to position the synchronizer hub on the wheel's axis of rotation if the hub does not have a central recess for the shaft connecting the motor to the wheel (or if the wheel hub does not have a central recess for the secondary shaft). In this embodiment, the synchronizer hub is bulkier and can also be more expensive to manufacture, particularly if it incorporates ball bearings. One solution is to position it on the side of the wheel opposite the vehicle chassis, as shown in Figures 10 and 11.

[0093] In a particularly advantageous embodiment, not shown, the motor of a wheel according to the invention is located in the wheel itself. In this case, the wheel no longer has a shaft to connect to the external drive hub, and the synchronizer hub can be located on the wheel's axis of rotation to determine the position of all traction accessories, while being located on the side of the wheel connecting it to the vehicle chassis.

[0094] It is also possible to use a hubless wheel driven by its rim, to obtain the same advantage.

[0095] The synchronizer can advantageously be constructed of a material or have an architecture that allows it to undergo elastic deformation. This means that, if the friction due to the movement of a traction accessory from one position to another exceeds a certain threshold, it can deform to cease producing the expected effect, and thus avoid causing damage to the traction accessory in question or to the synchronizer.

[0096] Without departing from the scope of the invention, a wheel may be fitted with one or more circular flanges allowing it to roll on the ground. The same applies to a track that may be fitted with an auxiliary track supporting part or most of the vehicle's weight.

[0097] In a particular embodiment, the wheels or tracks constituting the traction device according to the invention may be less dense than water in order to contribute to the buoyancy of the vehicle when it travels on water. They may even provide its buoyancy on their own.

[0098] Wheels or wheel parts located between traction accessories, inflated at low pressure or made of very flexible materials, can ensure comfortable rolling and effective traction on uneven ground. This also applies to tracks or track links.

[0099] Figure 5 illustrates an implementation particularly suited to this case. The left wheel has controls for deploying / retracting the blades (51 for blade 21) while the right one does not, the blades being either each positioned according to the resistance of the ground or according to an autonomous deployment / retraction device.

[0100] The advantage provided by the fact that the housings 210 and following of the traction accessories are fixed only to the band not equipped with the wheel IA is important, because in this case these housings can be rigid and allow deployment with low friction of the traction accessories.

[0101] A mechanical means (not shown) may be provided for certain traction accessories to automatically move into the deployed position when the force exerted by the traction device on the vehicle chassis is less than a certain value predetermined. This allows, for example, the accessories to automatically move into the deployed position when the vehicle floats on water, since the force exerted by the traction device on the vehicle's chassis is then reduced.

[0102] In a particular, unshown, embodiment, the traction accessories are not permanently linked to the wheel or track. A so-called selector device has the effect of - either in a first configuration of moving the traction accessories into a retracted position, and then they stack on top of each other, without being driven by the wheel or the track, - or, in a second configuration, to move them into the deployed position, in which they are driven with the wheel or track, moving away from the tangent plane at the periphery of the wheel or track, as the case may be. A complementary device allows the traction accessories that will move towards the top of the wheel or track to move into the retracted position.

[0103] Those skilled in the art know how to equip the traction device with means to prevent foreign bodies from slipping between the traction accessories and the fixed parts of the traction device. They can provide clearance between the faces of the traction accessories and the fixed parts that guide their extension / retraction, and use elastic parts to prevent these foreign bodies from damaging the device or the traction accessories, or from blocking extension / retraction, while also driving these foreign bodies in a preferred direction to allow their expulsion either towards the periphery of the traction device or in the opposite direction. These means are numerous, known to those skilled in the art, and are not shown here.

[0104] The invention also includes a vehicle equipped with a traction device like those described above. Advantageously, such a vehicle comprises the part of the synchronizer that does not rotate with the traction device, and / or a means for adjusting the elastic resistance of the elastic return 31, and / or a means for modifying the configuration of the synchronizer, and / or a means for controlling these two adjustment or modification means.

[0105] In a particularly advantageous embodiment illustrated by [Fig. 8], the vehicle is equipped with an obstacle-crossing aid device 70 connected directly or indirectly to the vehicle chassis by a mechanical linkage such that it lifts the vehicle when encountering an obstacle by moving from a retracted position, in which it is not in contact with the solid or liquid support on which the vehicle rests, to a deployed position in which it supports the vehicle with the obstacle in question. This obstacle can be solid, a wave, or an overpressure of the fluid on which the vehicle is traveling. All obstacle-crossing aid devices described in patent application FR3048404A3 of 8 September 2017 of the applicant may be used without departing from the scope of the present invention.

[0106] The invention is also the method of maneuvering a vehicle equipped with a traction device according to the invention, by a human operator or a computer, the maneuvering of the vehicle comprising a step of modifying the configuration of the synchronizer by a control means of the configuration modification means and / or a step of adjusting the elastic resistance of the elastic return 31 by the control means of the adjustment means of this resistance. Applications

[0107] The present invention applies to all land vehicles, from bicycles to trucks and including passenger vehicles, to save energy and allow automatic adaptation to traffic conditions.

[0108] The most astonishing applications of the present invention are land vehicles that can travel on roads as well as on uneven or muddy ground and sail on water or in certain versions take off and land vertically and fly in all directions, as well as a large or small boat, a submarine navigating in the water or rolling on the bottom, or an aircraft, all these vehicles being able to land on a beach and cross shallows without damage.

[0109] These vehicles can be used for leisure or work, rescue, public works but also for military combat.

[0110] They can be piloted by humans, whether passengers or not, using remote control means, or by computers.

[0111] Another important benefit is to make many rivers navigable which are not currently so.

[0112] The main vehicles likely to benefit from the invention are the following: - small fishing boats on rivers or ponds, or in marshes, - tenders for pleasure boats, - barges and recreational canal boats, - military ground drones, certain tanks, artillery equipment or missile launchers, and more generally military equipment that must be able to be transported autonomously from one point to another, - Public works or agricultural vehicles that must cross wet, muddy or snowy areas, - and remote-controlled vehicles for recreational use such as toys, but all land, water or air vehicles are concerned, including fast vehicles provided that the position of the traction accessories is not varied during the cycle when this risks harming the balance of the wheels.

Claims

1. Demands Vehicle traction device such as a wheel (IA) or a track (IB) comprising - a plurality of so-called traction accessory elements (21, 22 and following), - and a so-called deployment / retraction mechanism allowing a traction accessory to deploy from a so-called retracted position, in which it is closer vertically to the axis of rotation of said wheel or of that of the roller supporting said track as the case may be, to a so-called deployed position, in which it is further away, and conversely to retract, characterized in that one of said traction accessories: - includes, at least in one of its possible positions, a flexible portion of the outer surface of said tread, - and does not retract under the effect of a force applied to it giving rise to a rotational moment applied to said device, in the two directions of rotation called forward and reverse, if this rotational moment is less in the direction of rotation called forward than a first predetermined threshold, and in the direction of rotation called reverse than a second predetermined threshold, and that all of said traction accessories can be simultaneously in the retracted position, it being specified that the above and below are understood - by tread the outer part of said traction device, including said traction accessories, that is to say the part which comes into contact with the ground when the latter is flat and hard, - by unequipped strip, the part of said tread without said traction accessories, which includes, where applicable, the carcass of said tread, i.e. the framework which ensures its strength and resistance to load, - by deploying and retracting the movements of a traction accessory going respectively in the direction from the retracted position to the deployed position and in the opposite direction, - and by cycle the complete sequence during which one of said traction accessories makes a complete turn of said wheel or said track as the case may be.

2. A vehicle traction device such as a wheel (IA) or a track (IB) comprising - a plurality of elements called traction accessories (21, 22 and following), - and a mechanism called deployment / retraction allowing a traction accessory to deploy from a retracted position in which it is closer vertically to the axis of rotation of said wheel or to that of the roller supporting said track as the case may be, to a deployed position in which it is further away, and conversely to retract, characterized in that said traction accessory is a blade contributing to the traction of the vehicle by its pressure on a fluid or a granular medium, and that all of said traction accessories can be simultaneously in a retracted position

3. A traction device for a vehicle such as an airless tire, consisting of a central hub and an unequipped band connected by multiple elastomer links ensuring the elastic deformability of the tire (IA) comprising - a plurality of elements called traction accessories (21, 22 and following), - and a mechanism called deployment / retraction allowing a traction accessory to deploy to move from a position called retracted in which it is closer vertically to the axis of rotation of said wheel or to that of the roller supporting said track as the case may be, to a position called deployed in which it is further away, and conversely to retract, characterized in that said traction accessories are placed between said links when they are in the retracted position.

4. Traction device according to any one of the preceding claims characterized in that one of said traction accessories: - comprises an elastic return means (31) allowing the retraction of said traction accessories when an obstacle opposes their deployment during the cycle.

5. A traction device according to any one of the preceding claims, characterized in that the assembly consisting of one of said traction accessories and its deployment / retraction mechanism can, in one of its possible positions, extend beyond the thickness of said unequipped strip to be located partly in a volume whose periphery is the inner face of the unequipped strip.

6. Traction device according to any one of the preceding claims characterized in that the maximum travel of one of said traction accessories is greater than the thickness of said unequipped band.

7. Traction device according to claim 4 characterized in that it comprises a means for adjusting the elastic resistance of said elastic return.

8. Traction device according to any one of the preceding claims characterized in that it is equipped with traction accessories of several different kinds.

9. Vehicle equipped with a traction device according to any one of the preceding claims characterized in that it comprises the fixed part of said synchronizer which does not rotate with said traction device.

10. A method of maneuvering a vehicle according to claim 9, by a human operator or a computer, characterized in that the maneuvering of said vehicle includes a step of modifying the configuration of said synchronizer by a control means of said means of modifying said configuration and / or a step of adjusting said elastic resistance of said elastic return (31) by the control means of said means of adjusting this resistance.