Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C7/00—Non-inflatable or solid tyres
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D30/00—Producing pneumatic or solid tyres or parts thereof
  • B29D30/02—Solid tyres ; Moulds therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C7/00—Non-inflatable or solid tyres
  • B60C7/08—Non-inflatable or solid tyres built-up from a plurality of arcuate parts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C7/00—Non-inflatable or solid tyres
  • B60C7/10—Non-inflatable or solid tyres characterised by means for increasing resiliency
  • B60C7/102—Tyres built-up with separate rubber parts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C7/00—Non-inflatable or solid tyres
  • B60C7/10—Non-inflatable or solid tyres characterised by means for increasing resiliency
  • B60C7/14—Non-inflatable or solid tyres characterised by means for increasing resiliency using springs
  • B60C7/143—Non-inflatable or solid tyres characterised by means for increasing resiliency using springs having a lateral extension disposed in a plane parallel to the wheel axis
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C7/00—Non-inflatable or solid tyres
  • B60C7/22—Non-inflatable or solid tyres having inlays other than for increasing resiliency, e.g. for armouring

Definitions

• the present invention generally relates to non-pneumatic tyres. BACKGROUND ART This section illustrates useful background information without admission of any technique described herein representative of the state of the art.
• Conventional tyres for vehicles comprise pneumatic and non-pneumatic tyres.
• a pneumatic tyre is an air-filled covering for a wheel, typically of rubber or similar elastic material, whilst a non-pneumatic tyre is a solid tyre or another tyre missing the air fill feature of the pneumatic tyre.
• Both pneumatic and non-pneumatic tyres have their typical areas of application. Both tyre is fitted around the wheel's rim to absorb shocks and to provide traction, and steering, i.e., acting at its outer perimeter as the interface between the wheel and ground.
• Non-pneumatic tyres typically have much lower permissible speeds compared to pneumatic tyres.
• a non-pneumatic tyre of a vehicle comprising:
• a layered structure between an inner perimeter of the tyre and the tread comprising:
• the layered structure is a compound/composite structure that may be mounted on a wheel's rim. It may be mounted on the wheel's rim at its inner radial circumference (inner perimeter).
• the heat evacuation layers extend from the interior of the tyre to both lateral side walls of the tyre.
• the heat evacuation layer may contain axially oriented heat conductors. In certain example embodiments, the heat conductors extend from one lateral side surface to the other lateral side surface of the tyre.
• the tread at the outer circumferential perimeter of the tyre may provide an outermost surface of the tyre having a tread pattern and acting as an interface between the tyre and ground (soil).
• the heat evacuation layers are turned against a lateral side of the layered structure so as to form an area transferring heat from the tyre to surrounding air (flow) by forced heat convection.
• the formed area basically covers the whole side wall, i.e., is basically of the size of the side wall. This in order to maximize the area of forced convection.
• the formed area is yet covered by a thin layer, which may be an elastomeric layer.
• the tyre in axial direction may be divided into a centre part (i.e., a portion of the tyre close to the centre of the tyre) and edge parts (i.e., portions of the tyre close to the respective side wall).
• the heat evacuation layers extend from the centre part to the side wall(s).
• the heat evacuation layers form tube-like layers extending from one side wall through the interior to an opposite side wall of the tyre.
• the tube-like layers may form circular surfaces.
• the ends of the heat evacuation layers turn into a direction parallel to the side wall.
• a cylinder-like structure may be formed.
• the heat evacuation layers when exiting from the interior of the layered structure bend at the side wall tightly against the lateral surface in an essentially inward-oriented (towards the wheel/tyre centre) radial fashion.
• the heat evacuation layers are flexible.
• the heat evacuation layers comprise heat conducting elements which are continuous and without joints and other discontinuities in their longitudinal direction.
• the tyre is provided with a bead.
• the bead may be arranged in a corner of the inner perimeter.
• Another bead may be arranged in an opposite corner of the inner perimeter. Accordingly, the beads may be arranged at the corners of the inner perimeter circular surface.
• an outermost heat evacuation layer is attached to a bead or bead wire of the tyre.
• the bead forms a bead-rim interface configured to cause pre-stressing of the tyre through the bead.
• the bead in itself may form the bead-rim interface.
• the bead-rim interface may be a part of a tyre-rim interface.
• the heat evacuation layers comprise metal material.
• the heat evacuation layers are formed of metal elements set adjacent to each other.
• the metal elements may extend axially (in accordance with the main axis of the wheel/tyre).
• the heat evacuation layers within the tyre may form belt-like structures.
• the metal elements may be elongated elements, such as cords, wires or strands. They may be arranged adjacent or parallel to each other and covered by an elastomeric coating, defined as elastomer skim, to obtain adhesion and to obtain flexible elastic properties.
• the metal elements arranged adjacent or parallel to each other may form with the elastomer skim a belt-like or ply-like structure.
• the metal elements may be oriented in a basically axial direction with respect to the central axis of the tyre/wheel.
• the metal elements may be held together by the elastomer skim, in a ply-like fashion.
• the metal elements are in tight adhesion with the elastomer skim.
• the tight adhesion may be achieved by a vulcanization or curing process.
• the heat evacuation layers in the area of the lateral sides of the tyre (turned ends area) have no elastomeric skim (or only a minimal amount of skim material) to maximize heat conduction from a heat evacuation layer to another.
• the tyre comprises a stabilizer layer underneath the tread.
• the stabilizer layer may be immediately adjacent to the tread.
• the stabilizer layer may be in the form of a circular surface.
• the stabilizer layer may be in the form of one or more belts and/or one or more plies.
• the belts/plies may be formed of metal and/or textile material, such as metal or textile cords or wires.
• the belts/plies may be used in pairs where two belts/plies are arranged at opposite angles to one another with respect to the tread centerline.
• the stabilizer layer may contain strip plies.
• the tyre may also contain belt wedges etc. located inside of the tread.
• the main orientation of the stabilizer belt (or of the elements forming the stabilizer belt) is circumferential. This is, in certain example embodiments, in contrast to the main orientation of the heat evacuation layers (or of the elements forming the heat evacuation layers) within the tyre which is axial (except the turned ends of the heat evacuation layers the orientation of which is radial).
• the layered structure is between the inner perimeter and the stabilizer layer. In certain example embodiments, the layered structure basically extends from the inner perimeter to the stabilizer layer. In certain example embodiments, the tyre structure comprises at least two heat evacuation layers inside of the tyre separated by an elastomeric layer. If the stabilizer layer is provided, the outermost heat evacuation layer may be adjacent to the stabilizer layer.
• the stabilizer layer comprises elongated elements, such as wires or cords oriented in parallel to the tread centerline.
• steel cord is used in the stabilizer layer.
• the tyre may comprise a stabilizer layer of metal and/or non-metal material in the immediate proximity of the tread (this layer being separate from the afore-mentioned heat evacuation layers). The function of the stabilizer layer is to restrict expansion, stabilize the area defined by the tread and provide impact resistance.
• the elongated elements, such as cords, forming the stabilizer layer may be with zero angle in respect to the tread centerline or, for example, laid pair-wise diagonally at opposite angles the orientation the orientation of the stabilizer layer thereby being basically circumferential.
• the elongated elements, such as cords etc., forming the heat evacuation layers, to the contrary, may run from the interior of the tyre towards the side-wall surfaces thereby having basically an axial orientation.
• the layered structure forming a major part of the tyre is considered the main structure of the tyre.
• the main structure extends from stabilizer belt(s) or ply/plies (stabilizer layer) inwards to the inner perimeter of the tyre, the main structure being a layered structure of alternating heat evacuation layers and elastomeric layers.
• the side walls of the main structure (and thus of the tyre as a whole) may be formed by ends of the heat evacuation layers turned (radially inwards) towards the centre of the tyre/wheel and pressed against the main (interior) structure.
• An outermost heat evacuation layer is the heat evacuation layer inside the tyre structure that resides closest to the tread (or stabilizer layer, if applied).
• the ends of the outermost heat evacuation layer (which are considerably longer than the ends of the other heat evacuating belts/layers) are turned tightly over and against the other ones.
• the ends of the outermost heat evacuation layer extend to corners of the inner perimeter so that they can be attached to a bead arranged in the tyre, for example, turned/wrapped around the bead or bead wire of the tyre or similar.
• the outermost heat evacuation layer has between itself and the tread only the stabilization layer.
• the inner perimeter in between the beads is formed of an elastomeric layer of the layered structure.
• the inner perimeter between the beads lacks enforcements wires (enforcement means). Accordingly, in certain example embodiments, the tyre lacks an inner edge belt.
• the inner perimeter provides a sloped circular surface.
• the circular surface is sloped from a centre part, for example its circumferential centerline, towards both side surfaces of the tyre.
• the rim is formed of correspondingly sloped two rim halves which meet at the point of said centre part.
• the inner perimeter provides an inner circular surface between the arranged tyre beads.
• This inner circular surface in certain example embodiments, has a sloped triangular orientation in its radial cross- section (the triangular tip pointed to the center axis of the tyre/wheel and protruding further radially inwards with respect to the radius of the beads).
• the outermost heat evacuation layer when coming out from the interior of the tyre, is on each lateral side turned tightly against the lateral side concerned, the lateral sides being formed by turned ends of the intermediate heat evacuation layers, so that this outermost heat evacuation layer forms in essence the outer lateral surface (side wall) of the tyre.
• the outermost heat evacuation layer thus covers the entire side wall. Being turned, the outer heat evacuation layer is wrapped around the bead (at the corners of the inner perimeter circular surface), thus forming pre- requisites to apply pre-stressing at the bead-rim interface.
• the elastomeric layer may be of rubber or other elastic material (elastomer).
• the elastomeric layers are quasi-homogenous in their structure.
• a quasi-homogenous structure herein means, for example, that the elastomer in elastomeric layers has regularly repeating void areas. They may be of a predetermined shape. The void areas may be of macroscopic or microscopic size depending on the embodiment.
• the tyre comprises a tyre-rim interface in between the beads configured to pre-stress the layered structure through the tyre- rim interface. The pre-stressing is compressive pre-stressing in the radial direction.
• the pre-stressing of the layered structure improves the fatigue life of the elastomer within the layered structure as well as reduces hysteresis losses within the layered structure thereby reducing heat generation within the structure.
• the pre-stressing effect in the layered structure is yet improved if the tyre comprises the stabilizer layer.
• pre- stressing of the type (ii) above contributes in obtaining tangential and radial pre- stress in the area defined by the stabilizer layer and tread as well as in obtaining pre-stress in the layered structure.
• the tyre comprises a tyre-rim interface allowing compressive pre-stressing of the tyre interior from the inner perimeter all the way to the stabilizer layer.
• the pre-stressing of the type (i) is local pre- stressing at the bead-rim interface, while the pre-stressing of the type (ii) is nonlocal pre-stressing extending throughout the tyre.
• the tyre comprises a tyre-rim interface to obtain both local and non- local pre-stressing of the tyre.
• the disclosed non-pneumatic tyre may be for example a tyre for a heavy duty multipurpose/off-road dual-purpose vehicle.
• the structural elements of the tyre may be integrated.
• the structural elements and the tyre form together an integral elastic whole. This can be achieved e.g. during a manufacturing process by vulcanisation. Alternatively, glueing or any other suitable production method may be used.
• a wheel assembly comprising a rim and the non-pneumatic tyre of the first aspect or of any of its embodiments mounted on the rim.
• Fig. 1 shows a cross section of a non-pneumatic tyre in accordance with an example embodiment
• Fig. 2 shows an example cross section taken at a center line in Fig. 1 ;
• Figs. 3-4 show the heat evacuation flow directions in the tyre of the type of
• FIG. 1 in accordance with an example embodiment
• Fig. 5 shows a magnified view of a side wall area in Fig. 3;
• Figs. 6A-6G show examples of elastomeric layers in accordance with an example embodiment
• Fig. 7 shows pre-stressing of the tyre in accordance with an example embodiment
• Fig. 8 shows a further illustration of the pre-stressing in accordance with an example embodiment.
• Fig. 1 shows a cross section of a non-pneumatic tyre in accordance with an example embodiment.
• the tyre is mounted on a rim 1 and comprises a substantially cylindrical tread 7, and a layered structure that on its inner perimeter is mounted on the rim 1 .
• the layered structure comprises heat evacuation layers 4 alternating with elastomeric layers 8.
• the tyre further comprises a stabilizer layer 6 underneath the tread 7.
• the stabilizer layer 6 may be in the form of one or more belts and/or stabilizer plies formed of metal and/or non-metal material, such as cords or strands, covered with a coating, such as an elastomer skim.
• the tyre comprises lateral side walls.
• the heat evacuation layers 4 are in the axial direction longer than the width of the tyre main structure, and when exiting out of the main body of the tyre structure they bend and lay tightly against the side walls, with the ends in a direction towards the centre of the wheel.
• Each side wall has as its outermost surface a thin elastomeric layer 2 forming a smooth wear resistant outer surface and thus covering the outermost heat evacuation layer(s) that lays tightly against the turned (shorter) ends of the other evacuation layers 4.
• the elastomeric layers 8 separating the heat evacuation layers 4 are tube-like layers. In certain example embodiments, they are covered by the turned/bent ends of the heat evacuation layers 4 on the lateral sides (side walls) of the tyre.
• the tyre comprises a bead in a corner of the inner perimeter. Another bead is arranged in an opposite corner of the inner perimeter.
• the layered structure is attached to the bead. In certain example embodiments, the layered structure is attached to the bead by an outermost heat evacuation layer 4. In Fig. 1 the layered structure is shown as attached, or tied, to a bead wire 5 comprised by the bead.
• the rim 1 may be formed by rim halves which may be attached together by a bolt joint 9 as shown in Fig. 1 .
• the tyre shown in Fig. 1 also comprises an optional deflector 10 at a bottom corner (shoulder) of the tyre.
• the heat evacuation layers 4 extend from the interior of the tyre to a side wall of the tyre. Their ends are turned against the lateral surfaces of the interior structure. In certain example embodiments, the heat evacuation layers extend from side wall to side wall.
• the format of the heat evacuation layers 4 depends on the implementation.
• Fig. 1 shows two example alternatives. The right-hand side of Fig. 1 shows heat evacuation layers 4 arranged perpendicularly to the tyre center line 3 (thus extending horizontally cylindrically and axially towards the side wall), and the left-hand side of Fig. 1 shows heat evacuation layers 4 extending towards the side wall at an inclined angle. To optimize performance, the arrangement of the heat evacuation layers 4 may vary in the radial cross section of the tyre according to the temperature gradients and/or the stress distributions.
• the heat evacuation layers 4 are metal layers. They may be formed of metal wires set adjacent to each other forming a belt-like structure and being covered by skim, or they may be formed of a plurality of thin strands set adjacent to each other and covered by skim. Or, they may be metal cord layers.
• the parts which form the heat evacuation layers 4 function as heat conductors travelling sideways (contrary to circumferential direction) towards the tyre outer surfaces where the internal heat conduction changes/transforms into heat transfer by essentially forced convection and partially into radiation.
• the heat evacuation layers 4 are flexible in the radial and tangential direction of the tyre due to the elasticity of the elastomeric skim providing elasticity between the cords/strands.
• Fig. 2 shows an example cross section of the tyre of Fig. 1 taken at the center line 3 in Fig. 1 .
• the heat evacuation layers 4 form belt-like structures in which the direction of the heat conductors forming partly or entirely the layers is from the interior towards the side walls (contrary to the circumferential general orientation of the stabilizer layer 6 (or the elements forming the stabilizer layer 6).
• Figs. 3 and 4 show the directions of conductive heat evacuation flow in the tyre structure of the described type
• Fig. 5 shows a magnified view of side wall area marked in Fig. 3 where the conductive heat flow changes into heat transfer by forced convection.
• Fig. 3 shows the outermost heat evacuation layer 4i positioned in the interior of the tyre next to the stabilizer layer 6.
• An outermost elastomeric layer 81 resides next so that the outermost elastomeric layer 81 separates the outermost heat evacuation layer 4i and a second heat evacuation layer 42.
• a second elastomeric layer 82 residing on the rim-side of the second heat evacuation layer 42 separates the second heat evacuation layer 42 and a third heat evacuation layer 43.
• a third elastomeric layer 83 residing on the rim-side of the third heat evacuation layer 43 separates the third heat evacuation layer 43 and a fourth heat evacuation layer (not shown), and so on. The composite structure thus formed continues further until the rim is reached.
• the ends of the outermost heat evacuation layer 4i are turned tightly against the turned ends of the other heat evacuation layers 42, 43.
• the ends of the outermost heat evacuation layer 4i being turned into the direction towards the centre of the tyre, travels all the way from an area close to the tread 7 to the bead wire 5 and is tied around it (as shown in Fig. 1 ).
• the elastomeric layers 8 are tube-like structures in between the heat evacuation layers 4.
• the ring/tube-shaped ends of the elastomeric layers 8 at the lateral sides of the tyre are covered by the tightly lying turned ends of the heat evacuation layers 4.
• the ends of the inner elastomeric layers 82 and 83 are covered by the ends of the inner heat evacuation layers 42 and 43, respectively.
• the outermost elastomeric layer 81 is covered by the outermost heat evacuation layer 4i which continues radially inwards covering also the turned ends of the inner heat evacuation layers.
• the outermost heat evacuation layer 4i extends over the entire lateral side(s) of the tyre. It lies tightly against the turned ends of the inner heat evacuation layers.
• a large heat conduction surface is formed to maximize heat conduction flow to an outer surface of the tyre and thus to obtain a maximized surface for heat transfer by forced convection from the outer surface into the surrounding air flow.
• the different heat evacuation layer ends at the lateral sides have a minimal amount of possible elastomeric material separating the heat conductors (cords, wires and/or strands, etc.) from each other. This tight and close overlapping of the heat conductors maximizes the conductive heat flow to the outermost heat evacuation layer and then further to the very surface of the tyre, with an optimal distribution of heat transfer over the tyre lateral surfaces.
• the heat conductive elements are continuous and without joints and other discontinuities in their longitudinal direction to maximize heat transfer by heat conduction.
• the contacts between adjacent heat evacuation layers are intimate contacts to maximize the heat conduction in the transverse direction from one conductive element layer (heat evacuation layer) to the next one.
• the conductive elements in their longitudinal direction may have intimate contact with adjacent conductive elements of the same conductive element layer.
• Heat generated in the tyre is evacuated via the heat evacuation layers 4 formed of heat conductors (e.g., metal wires/cords/strands) to the side walls, where the heat flow is distributed over the entire side walls and then transferred essentially by forced convection (air-speed generated by the combination of the vehicle translatory movement and the rotative movement of the wheel) as indicated by the dotted arrows in Fig. 3 and also to a lesser degree by radiation into the surrounding air.
• the heat first travels by conduction from the elastomeric layers 8 into the heat evacuation layers 4 and then along the heat conductors of the heat evacuation layers 4 (also by conduction) to the side wall. This is indicated by the small arrows shown in Fig. 3.
• Fig. 4 further shows the heat flow, or heat flux, within the tyre at section A-A.
• Heat generated in the inner parts (interior) of the tyre is removed from the tyre structure at its outer surfaces (tyre-surrounding environment interface) by forced convection and also by radiation.
• the temperature levels, as indicated in Fig. 4, in the elastomer layer 82 between heat evacuation layers 42 and 43 dictate the direction of conductive heat flow within the structure.
• the magnified view of the marked area of Fig. 3 in Fig. 5 shows the outermost heat evacuation layer 4i arranged as described in the foregoing.
• the outermost heat evacuation layer 4i is covered only by a thin outer elastomeric layer (or covering layer) 2 that should be of minimal thickness.
• FIG. 5 also shows the turned end of the second heat evacuation layer 42 travelling on the inner side of the outermost heat evacuation layer 4i, and ending at the point where the third heat evacuation layer 43 contacts the side wall. At that point the third heat evacuation layer 43 turns into the direction parallel to the side wall. Therefrom the third heat evacuation layer 43 travels on the inner side of the outermost heat evacuation layer 4i as a continuation of the second heat evacuation layer 42, and so on.
• Figs. 6A-6G show examples of elastomeric layers in accordance with certain example embodiments.
• Fig. 6A shows a cellular elastomer layer 8 in between the heat evacuation layers 4.
• Figs. 6B-6G show elastomeric layers 8 having regularly repeating void areas 1 1 of a predetermined shape in between the heat evacuation layers 4, the elastomeric layers 8 thus forming a quasi-homogenous structure.
• the alternating elastomeric layers and the heat evacuation layers can be added one by one during the manufacturing process, there is a considerable freedom to choose for each elastomer layer an elastomer with suitable properties, and by choosing suitable voids (in conjunction with the chosen elastomer type) desired behavior of the individual elastomer layers can be obtained.
• suitable voids in conjunction with the chosen elastomer type
• the possibility to form the voids in the elastomeric layers in many ways gives the possibility to influence in a wide range the compressive behavior of these layers.
• the voids in the elastomeric layers contribute significantly to the reduction of the elastomer mass of the tyre. This contributes considerably to the reduction of the rolling resistance, since the value of the rolling resistance coefficient is proportional to the mass of the elastomeric material in the tyre.
• Fig. 7 shows pre-stressing of the tyre at the inner perimeter in accordance with an example embodiment.
• the pre-stressing of the tyre through the inner perimeter circular surface is achieved by axial pressing of two outwardly sloped rim halves towards each other, thus exerting compressing forces in radial direction.
• the differences in the corresponding diameters of the rim halves and the unstressed tyre are such that diameters of the unstressed tyre are smaller than the corresponding diameters of the rim. Pre-stressing firstly through bead-rim interface and secondly through an interface between the rim and sloped tyre surfaces is obtained in a controller manner when a sloped form of the rim and tyre surfaces are pressed together.
• Fig. 8 shows changes in radial dimensions at the area marked in Fig. 7 when mounting the tyre on the rim 1 .
• the radial displacement ⁇ generates radial pressures that by friction contribute to secure a safe mounting, transfer of the torque moment and keeping the tyre on the rim (basically due to the pre-stressing at the bead wire 5).
• the radial displacement ⁇ 2 further contributes to give the tyre a pre-stressed condition inside the main compound layered structure, improving the fatigue life and hysteresis loss properties, as well as to avoid rubbing or loosening between the tyre and the rim.
• Pre-stressing in accordance with the shown compound structure of superposed tubes (or the like) of the tyre is advantageous in reducing the amplitude of pulsating cyclical stresses applied to the tyre when driving as well as to shift the mean value of the cyclically variable stresses.
• the radial pre-stressing acts as a permanent background pressure field.
• the other tensile, compressive and shear stresses are superposed on the generated background pressure field, with reciprocal interferences.
• reduction in hysteresis losses signifies reduction in heat generation and thus in the coefficient of rolling resistance and consequently signifies an improvement of the performance of the tyre.
• the described elastic tyre When transmitting vertical and horizontal forces as well as the torque (driving and braking forces), acting on the wheel into the soil/ground, the described elastic tyre is subjected to alternating, pulsating cyclical stresses and deformations that due to the hysteresis (dissipated, non-recuperated part of the energy stored in the material during its loading cycle) produce continuously heat.
• This heat flow is directed from the hotter parts towards the parts with lower temperature along temperature gradients, resulting in a conduction of heat energy (i.e., heat flow) to the outer surfaces of the tyre (boundary between tyre and surrounding environment) in such a manner that there is an equilibrium between an internal heat flow to the tyre surface and the transfer of heat from the tyre surface to the surrounding environment. If at any moment the heat generation in the tyre is bigger than either the internal conductive capabilities or the transfer capabilities at the boundary between tyre and the surrounding environment, then there is an increase in the temperature fields and their gradients, so that a temporary equilibrium again is achieved, until a steady state of the heat flow equilibrium is achieved.
• elastomers have a comparative modest thermal operational level at which they lose their functional properties.
• the presented embodiments show efficient heat transfer with optimal temperature gradients from the interior of the tyre to the outer surfaces of the tyre via the layered structure.
• the presented embodiments also show less heat generation in the tyre via pre-stressing the layered structure.
• the presented embodiments also show effective heat transfer into the surrounding environment by forced convection.
• the distribution of heat over the entire lateral side surface(s) of the tyre is practically an even distribution in certain example embodiments. An abrupt temperature drop at the boundary between the tyre and the surrounding environment may be achieved.
• the presented embodiments also show reduction in the mass of elastomers in the tyre via the voids within the elastomer layers (since the dissipation of energy (hysteresis losses) is proportional to the elastomer mass of the tyre, the tyre properties may be improved by the reduction of the mass of elastomers in the tyre).
• the presented embodiments improve operational characteristics of non-pneumatic tyres, especially combinations of permissible speed and permissible load (maximal permissible load with corresponding maximal permissible corresponding speed).
• the layered structure or part of it is formed from a belt-like compound structure consisting of an elastomer layer and a heat evacuation placed (joined) on top of each other.
• the belt-like structure is rolled in a spiral fashion to form the interior of the tyre, or part of it.
• the lateral sides of the tyre are formed similarly as described in the foregoing.

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• Tires In General (AREA)

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Citations (9)

• 2015
  • 2015-06-15 FI FI20155459A patent/FI126666B/fi active IP Right Grant
• 2016
  • 2016-05-06 WO PCT/FI2016/050293 patent/WO2016203098A1/en active Application Filing

Patent Citations (9)

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