Technical field

The invention relates to an assembly of vehicle travel wheels for road and/or off-road use, consisting of two travel wheels mounted in parallel.

Background art

With conventional motor vehicles intended for road use, overcoming even light off-road terrain is problematic and always poses a risk of their getting stuck in the terrain and possible damage to the vehicle. All road vehicles eliminate this drawback, but their off-road use is only possible up to a certain degree of terrain difficulty. This is determined not only by the unevenness of the terrain, but also by the terrain surface, which requires means to increase the traction of the wheels, for example in mud, snow, sand and the like.

CZ 303947, published also as EP 2616252 and WO 2012034545, discloses a travelling wheel of a vehicle for on-road and/or off-road driving, whose principle consists in that circumferential segments are arranged in the body of the travelling wheel displaceably between the position for on road driving and the position for offroad driving in which the individual circumferential segments are deviated from the circumferential direction of the travelling wheel, wherein gaps formed between the circumferential segments in the circumferential direction of the travelling wheel interrupt the rolling surface of the travelling wheel. When the circumferential segments are set to the circumferential direction, the travelling wheel behaves like a conventional travelling wheel, which is advantageously usable on the surface of normal roads. After turning the circumferential segments to oblique positions relative to the wheel circumference, circumferential gaps are formed between the segments, improving the vehicle's ability to drive through uneven and/or incoherent terrain. The angle of rotation of the segments can be set according to specific driving conditions. In an embodiment in which the axis of the swivel pin is non-parallel with respect to the axis of rotation of the travelling wheel, it is also possible to increase the wheel track by turning the circumferential segments, which increases the stability of the vehicle on uneven and/or sloping terrain. However, this solution is relatively complex, requires a number of additional functional elements and can be difficult in terms of maintenance and service.

US 3 418 960 A discloses an amphibious vehicle in which, before it is put on the water surface, conventional vehicle wheels on the drive axle are replaced with wide cylindrical hubs fitted with helix-shaped radial blades. These are either fixed or adjustable by rotating around radial pins, or deformable to create the desired shape in a different manner. The shape of the blades is intended to enable propulsion when the vehicle is floating on the water surface and to facilitate the transition of the vehicle over very difficult terrain adjacent to water surface. The solution is only applicable for the above purpose and is not intended for land wheeled vehicles, which is reflected in the design of the supporting hub, the shape of the blades and the manner they are rotated.

The solution according to DE 10046421 uses a flat disc arranged on the face of a travel wheel provided with a conventional tyre. The outer diameter of the disc is smaller than the rolling diameter of the tyre. In the radial holes on the circumference of this disc are fitted with extending spikes, which, after the intervention of the vehicle driver, project above the rolling diameter of the tyre and allow, for example, driving on snow-covered or frozen ground. However, this solution basically only serves to free the vehicle from a certain impassable section of the terrain.

The solutions according to DE 19912553, or similarly according to DE 19950946, describe a device in which, if necessary, engagement means forming ribs on the tread parallel with the axis of rotation of the travel wheel are moved to the surface of the tyre tread. These relatively complex devices are mounted on the faces of the travel wheels. They are effective, for example, on snow-covered road surfaces, their function corresponds to that of snow chains, whereby they are brought into working position on the wheel by the driver's control means while the vehicle is in motion.

EP 1683653 discloses a device designed to be mounted on vehicle wheels to increase their roadholding in the presence of snow or ice, which includes a support on which a plurality of spikes are fitted, which, when the support is mounted on the wheel, are located in a radial position projecting from the external circumference of the tyre, so that when the tyre touches the snow- or ice-covered ground, the spikes penetrate into said snow- or ice-covered ground. The device comprises a hub designed to be attached to the vehicle wheel with bolts screwed into the same threaded holes as the support of the wheel. The disadvantage of this solution is the need to manually mount the support if needed.

The travel wheel according to EP 0 930980 is configured as a dual wheel, when in a gap between two discs with conventional tyres, a further narrower disc is arranged, on which a special traction tyre is mounted, the tread of which is provided with engagement protrusions, e.g., studs. At low air pressure in the traction tyre the engagement protrusions are below the level of the treads of adjacent conventional tyres. If necessary, the traction tyre is inflated in the usual manner to a pressure at which the engagement protrusions rise above the level of the treads of the adjacent conventional tyres, thereby increasing adhesion, for example, on snow-covered surfaces.

US 6 273 517 proposes to attach a ring into an inner circumference of a disc of a travel wheel with a classic tyre in direction from its outer face. In the ring are arranged radial paddles extending outward from the face of the wheel, wherein in a radial direction they do not exceed the surface of the tyre tread. They are made of a resilient tough material, which upon contact with a large solid obstacle deforms for a short term without damage. The device increases the vehicle's ability to drive on snow, mud and sand.

Some solutions according to the background art allow in some cases shortterm vehicle movement on unpaved terrain, but are essentially unsuitable for longterm off-road driving and/or on paved roads. Other solutions improve the traction conditions when driving on low adhesion roads, but are not suitable for off-road driving on sandy, muddy and/or snowy terrain which is, moreover, extremely uneven.

Most solutions according to the background art are complex and complicated and require high costs for both production and service.

The objective of the present invention is therefore to provide a combination (assembly) of wheels which would be suitable for driving a vehicle on a normal road, whereby a simple solution would facilitate movement on slippery roads covered with slush or mud and allow movement over difficult uneven, loose or rocky terrain, whereby the solution will have low costs for production, as well as service and maintenance.

Principle of the invention

The objective of the invention is achieved by an assembly of travel wheels of a vehicle for use on the road and/or off-road, the principle of which is that at least one of the wheels is provided with a full torus tyre and at least one of the travel wheels is provided with circumferential torus segments, whereby between these circumferential segments of the torus, gaps are arranged in the circumferential direction of the travel wheel to interrupt the rolling surface of the travel wheel.

The invention is based on the formation of at least a pair of travel wheels of a vehicle, wherein at least one wheel includes a set of segments in the shape of a portion of a torus, these segments being separated from each other by sufficiently large gaps in the shape of the remaining portion of the torus to interrupt the travel path of the wheel. On the contrary, at least one other wheel of the assembly is of the classic type, i.e., with a full torus tyre. In addition, when driving on a normal road, it is possible, by controlling the pressure of the full torus tyre, to controllably raise the wheel with the set of segments in the shape of the torus portion above the running surface or, conversely, to lower the wheel with the set of segments in the form of the torus portion onto the running surface. For example, by increasing the pressure in a full torus tyre to a value at which its radius is greater than the radius of the wheel with the set of segments in the shape of a portion of a torus, so that only the tyre in the form of a full torus, i.e., a normal wheel, is in contact with the road. On the other hand, when riding on difficult terrain, the tyre pressure of the tyre in the form of a full torus is reduced, so that the wheel with the set of segments in the shape of a portion of a torus abut the riding road surface and increases the traction of the assembly.

In the case of driving on difficult terrain, on the other hand, the tyre pressure of the wheel with the full torus tyre is reduced, so that the wheel with the set of segments in the shape of a portion of a torus sits on the driving surface and increases the traction of the assembly. Alternatively, the tyre pressure of the full torus tyre is reduced to such an extent that it is exclusively or almost exclusively the wheel with the set of segments that comes into contact with the ground, thus achieving a further significant change in the engagement conditions, i.e., traction, of the whole assembly. Gaps between the segments of the wheel with the set of segments, for example, make it easier to deal with stones in the terrain, prevent wheel slip in mud or sand, etc. The footprint of the wheel with the set of segments is thus discontinuous and resembles the gait of a human being. If the wheel with the set of segments is mounted in the assembly as an outer wheel relative to the longitudinal axis of the vehicle, i.e., the conventional wheel is the inner wheel in this assembly, stability is further increased by increasing the track width of the wheels, thus enabling the vehicle to pass more easily even under very adverse conditions (snow, ice, mud, sand, etc.). If the segments of the wheel with the set of segments are designed to be inflatable, then the internal pressure of these segments can also be controlled with similar effects, either individually or all segments simultaneously. Increasing or decreasing the pressure in one or both wheels can be done, e.g., from the driver's cab of the vehicle, as is usual with special transport equipment, or automatically, e.g., by the traction control system, etc.

Depending on the position of the wheel with the set of segments relative to the other wheel, i.e., the wheel with the full torus tyre, and relative to the longitudinal axis of the vehicle, i.e., the position from the outside or from inside towards the longitudinal axis of the vehicle, the application of the invention can also be used for example to extend the footprint of the vehicle when driving off-road and thus increase its stability against overturning, etc. The advantage of arranging the wheel with the set of segments on the inside of the assembly is, for example, the invisibility of the wheel with the set of segments when driving on a paved road, etc.

The consequence of this solution is a significant increase in the vehicle's ability to drive through difficult terrain while fully maintaining the ability to drive on paved roadways, as is the case with conventional wheeled vehicles. The solution is especially suitable for conventional off-road vehicles or cargo vehicles, transport and military vehicles of the army, mobile robots, for the landing of robotic vehicles on other planets - such as Mars rovers, etc.

By changing the pressure in the full torus tyre and/or segmented tyre, the wheel radii are changed so that only the full torus tyre can touch the road when driving on a normal road. When riding off-road, on the other hand, it is advantageous for the wheel with the set of segments to have a larger radius so that it is in contact with its own terrain, while the wheel in the form of a full torus does not touch the terrain or touches it only to a limited extent, e.g., in soft sand, mud, snow, etc. The resulting effect of changing the traction of each wheel can be achieved both by changing the pressure in both tyres and by changing the pressure in only one tyre. For example, the wheel with the set of segments is inflated at a constant pressure or is formed by solid material segments without a possibility of inflation and the pressure is changed only in the case of the wheel with the full torus tyre by inflating it or, conversely, by deflating it. Thus, by changing the tyre pressure, the wheel assembly adapts flexibly to the type of terrain (surface) on which the vehicle is moving. Pressure control can be achieved either by direct intervention of the vehicle driver or by an automatic control system, which is not part of this patent.

Description of the drawings

The invention is schematically represented in the drawings, wherein Fig. 1 shows a side view of an exemplary embodiment of the invention and Fig. 2 shows a front view of an exemplary embodiment of the invention.

Examples of embodiment

The invention will be described by way of examples of embodiment of an adaptive travel wheel of a vehicle in an assembly of a pair of travel wheels. However, the invention is also applicable in other particular travel wheel arrangements, based only on ordinary skill in the art. The invention consists in that the wheel assembly comprises a rolling surface with a parallel mounting of a tyre pressure regulating wheel and a wheel with fixed circumferential segments.

The travel wheel assembly according to the invention in the exemplary embodiment shown in Figs. 1 and 2 comprises a first wheel 1 , which is provided with a tyre 8 in the form of a full torus, thus forming a wheel with a tyre of a conventional type. The first wheel 1 is mounted on a common shaft 3 with a second wheel 2, which is provided with circumferential segments 4 of a torus, which in the illustrated embodiment are located substantially evenly around the circumference of the rim 7 of the second wheel 2. Gaps 5 are arranged between the segments 4. The ratio of the sum of the angular size of the individual segments 4 and the sum of the angular size of the individual gaps 5 is preferably in the range from 1/3 to 2/3.

The distribution of the segments 4 and the gaps 5_around the circumference of this wheel 2 is substantially uniform.

The individual segments 4 are configured either as a tyre with a common inflation or they are formed by separate parts which are individually inflated and are separately mounted on a common rim 7. In another embodiment, the segments 4 are made of a solid material without a possibility of inflation, for example porous rubber or other suitable material. To increase the strength, if necessary, the segments of porous rubber or other suitable material are provided with reinforcement, for example steel reinforcement or Kevlar or polyamide reinforcement, etc.

To facilitate the regulation of the tyre pressure, in the illustrated exemplary embodiment, each inflatable solid tyre 8 and/or inflatable segment 4 is connected to an unillustrated system for changing their internal pressure, which includes supplying a pressure medium to the tyre 8 and/or the segments 4, e.g., through a cavity in a supply 6 of the pressure air formed in the shaft 3, wherein the system further comprises an inflation control element, etc.

The invention is not limited to the embodiments explicitly described and illustrated herein, but, with knowledge of this description, it can also be implemented in other particular combinations and embodiments.

List of references

1 first wheel

2 second wheel

3 shaft

4 segment of the second wheel

5 gap between the segments of the second wheel

6 pressure air supply

7 rim of the second wheel

8 tyre of the first wheel