JP6929764B2 - Non-pneumatic tire - Google Patents

Description

The present invention relates to a non-pneumatic tire having a support structure for supporting a load from a vehicle as a tire structural member, and preferably a non-pneumatic tire that can be used as a substitute for a pneumatic tire. It's about tires.

Conventional non-pneumatic tires include, for example, solid tires, spring tires, cushion tires, etc., but do not have the excellent performance of pneumatic tires. For example, non-pneumatic tires are difficult to maintain stability in dimensions and rigidity under repeated load during running, or are inferior in durability to pneumatic tires, so the tire mileage is shortened. There was a challenge.

In Patent Document 1 below, a thermoplastic elastomer (A) having a side chain containing an imino group and / or a nitrogen-containing heterocycle and a carbonyl-containing group, and having a melting point of 280 ° C. or lower and two or more hydroxyl groups. A non-pneumatic tire obtained by using a thermoplastic elastomer composition containing a polyol compound (B) having a hydroxyl value of 500 or more as a raw material is described.

Further, in Patent Document 2 below, a resin composition containing 50% by mass or more of a polyamide resin obtained by polymerizing an aromatic diamine and an aliphatic dicarboxylic acid and less than 30% by mass of a flexible component having a glass transition point of 0 ° C. or lower. A tire in which a skeleton member is formed of a resin material made of a resin material is described.

Japanese Unexamined Patent Publication No. 2016-3265 Japanese Unexamined Patent Publication No. 2017-13681

However, as a result of diligent studies by the present inventor, in the tires described in the above patent documents, since all the tire constituent materials contain a thermoplastic elastomer, the compression set ratio of the finally obtained tire becomes large. As a result, it was found that the creep resistance of the tire tends to deteriorate and the durability of the tire tends to decrease.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a non-pneumatic tire having improved tire durability while improving creep resistance by reducing the compression set. be.

The above object can be achieved by the present invention as described below. That is, the non-pneumatic tire according to the present invention is a non-pneumatic tire provided with a support structure for supporting a load from a vehicle, and the support structure is provided concentrically on the inner annular portion and the outer side of the inner annular portion. The outer annular portion is connected to the inner annular portion and the outer annular portion, and a plurality of connecting portions are provided in the tire circumferential direction, and at least a part of the connecting portion is made of a resin material. The resin material is characterized by having a swelling degree of 15 to 70% by weight after being immersed in N, N-dimethylformamide at 80 ° C. for 1 week.

The non-pneumatic tire of the present invention includes an inner annular portion, an outer annular portion concentrically provided on the outer side of the inner annular portion, and a plurality of connecting portions for connecting the inner annular portion and the outer annular portion. There is. Since such a connecting portion is repeatedly subjected to a load when the tire is running, both deterioration of creep resistance and deterioration of tire durability are the most concerned points.

However, in the non-pneumatic tire of the present invention, at least a part of the connecting portion is made of a resin material having a swelling degree of 15 to 70% by weight after being immersed in N, N-dimethylformamide at 80 ° C. for 1 week. .. Since such a resin material has a small compression set, the non-pneumatic tire according to the present invention is excellent in both creep resistance and tire durability by providing the resin material at least in a part of the connecting portion.

In the non-pneumatic tire, it is preferable that the polymer constituting the resin material contains a chemically crosslinked structure. When the polymer contains a chemically crosslinked structure, it requires more force to give permanent deformation due to the restricted movement of the polymer molecular chains. As a result, a non-pneumatic tire having a connecting portion made of at least a part of such a resin material is excellent in both creep resistance and tire durability.

In order to further improve creep resistance and tire durability, it is preferable that the polymer constituting the resin material is thermosetting polyurethane in the non-pneumatic tire.

In the non-pneumatic tire, the intercrosslinking molecular weight of the polymer constituting the resin material is preferably 1000 to 32000 g / mol. When a chemically crosslinked structure is introduced into the polymer constituting the resin material and the molecular weight between the crosslinks is set to 1000 to 32000 g / mol, the crosslink density becomes high and a larger force is required to give permanent deformation. As a result, non-pneumatic tires with joints made up of at least a portion of such resin material are particularly excellent in both creep resistance and tire durability.

In the non-pneumatic tire, it is preferable that the chemically crosslinked structure of the polymer constituting the resin material is derived from a polyfunctional polyol. Further, in the non-pneumatic tire, the polymer constituting the resin material contains at least an isocyanate-terminated prepolymer and a polyfunctional polyol as raw materials, and the polyfunctional polyol is 0 with respect to 100 parts by weight of the isocyanate-terminated prepolymer. It is preferably contained in an amount of 1 to 5 parts by weight. Further, in the non-pneumatic tire, the polymer constituting the resin material contains a bifunctional chain extender as a raw material, and the ratio of the polyfunctional polyol to the bifunctional chain extender ((polyfunctional polyol) / ( The chain extender)) is preferably 0.02 to 5 by weight. When the non-pneumatic tire according to the present invention has these configurations, it is preferable because both creep resistance and tire durability are further improved.

Front view showing an example of the non-pneumatic tire of the present invention AA cross-sectional view of the non-pneumatic tire of FIG. Perspective view showing a part of the non-pneumatic tire of FIG. Partially enlarged view of the non-pneumatic tire of FIG. A cross-sectional view showing the first connecting portion of FIG. 2A. Tire meridian cross section of a non-pneumatic tire according to another embodiment Tire meridian cross section of a non-pneumatic tire according to another embodiment

The non-pneumatic tire according to the present invention connects the inner annular portion, the outer annular portion concentrically provided on the outer side of the inner annular portion, and the inner annular portion and the outer annular portion, and is independent in the tire circumferential direction. It is provided with a support structure including a plurality of connecting portions provided in the above manner. At least a part of the connecting portion is composed of a resin material, and the resin material is designed so that the degree of swelling after being immersed in N, N-dimethylformamide at 80 ° C. for 1 week is 15 to 70% by weight. .. In order to design the resin material so that the swelling degree after being immersed in N, N-dimethylformamide at 80 ° C. for 1 week is 15 to 70% by weight, for example, the resin material is composed of a polymer having a chemically crosslinked structure. Is preferable.

In the present invention, when a thermosetting polymer is used as the polymer constituting the resin material, it is preferable because the creep resistance and the tire durability of the finally obtained tire are improved as compared with the thermoplastic polymer. Examples of the thermosetting polymer include epoxy, phenol, polyurethane, silicone, polyimide and melamine, but in the present invention, it is particularly preferable to use thermosetting polyurethane. In the following, thermosetting polyurethane will be described as an example of the polymer constituting the resin material.

The thermosetting polyurethane contains at least an isocyanate component and an active hydrogen group-containing compound. However, in order to design the resin material so that the swelling degree after being immersed in N, N-dimethylformamide at 80 ° C. for 1 week is 15 to 70% by weight, and further to introduce a chemically crosslinked structure into the polymer. It is preferable to further use a polyfunctional polyol as a material for the thermosetting polyurethane. Further, in addition to the polyfunctional polyol, it is preferable to further contain a chain extender as a material for the thermosetting polyurethane.

When a thermosetting polyurethane is used as a polymer, a one-shot method and a prepolymer method can be mentioned as a method for producing the same. In the one-shot method, an isocyanate component, an active hydrogen group-containing compound, a polyfunctional polyol and a chain extender, if necessary, can be blended, and these can be polymerized at the same time. However, considering the creep resistance and tire durability of the finally obtained non-pneumatic tire, it is preferable to produce the thermosetting polyurethane by the prepolymer method. In the prepolymer method, for example, an isocyanate-terminated prepolymer can be produced from an isocyanate component and an active hydrogen group-containing compound as raw materials, and a polyfunctional polyol and / or a chain extender can be added thereto and polymerized. ..

As the isocyanate component, a compound known in the field of polyurethane can be used without particular limitation. For example, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, polypeptide MDI, carbodiimide-modified MDI, 1,5. Aromatic diisocyanates such as −naphthalenedylene diisocyanate, p-phenylenediocyanide (PPDI), m-phenylenediocyanide, p-xylylene diisocyanate, m-xylylene diisocyanate, ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1, Examples thereof include aliphatic diisocyanis such as 6-hexamethylene diisocyanate, 1,4-cyclohexanediisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and alicyclic diisocyanate such as norbornan diisocyanate. These may be used alone or in combination of two or more. However, among the above isocyanate components, it is preferable to use PPDI because the obtained resin material becomes rigid and the compression set rate can be reduced.

Examples of the active hydrogen group-containing compound include polycarbonate-based polyols, polyether-based polyols, polylactone-based polyols, and polyester-based polyols. Examples of the polycarbonate-based polyol include a polyol obtained by dealcoholization of a polyhydric alcohol such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, octanediol, and nonanediol with diethylene carbonate, dipropylene carbonate, and the like. Can be mentioned. Examples of the polyether polyol include polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol and the like. Examples of the polylactone-based polyol include polycaprolactone glycol, polypropiolactone glycol, and polyvalerolactone glycol. Polyester-based polyols include polycarboxylic acids such as terephthalic acid, phthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, and 1,6-. Examples thereof include esters of polyhydric alcohols such as hexanediol and neopentyl glycol. Among the above, it is preferable to use a polycarbonate-based polyol, and particularly preferably a bifunctional polycarbonate-based diol, because the obtained resin material becomes rigid and the compression set can be reduced.

Polyfunctional polyols are polyols having at least three or more reactive functional groups, such as trimethylolpropane, glycerin, 1,2,6-hexanetriol, meso-erythritol, pentaerythritol, tetramethylolcyclohexane, methylglucoside, and sorbitol. Mannitol, dulsitol, sucrose, 2,2,6,6-tetrax (hydroxymethyl) cyclohexanol, triethanolamine, and trifunctional or higher functional polycarbonate-based polyols, polyether-based polyols, and polylactones obtained using these as initiators. Examples thereof include based polyols and polyester based polyols. Among these, trimethylolpropane and glycerin are preferably used, and trimethylolpropane is particularly preferable, because the obtained resin material becomes rigid and the compression set can be reduced. In order to optimize the chemically crosslinked structure of the heat-curable polyurethane, especially in order to make the intercrosslinking molecular weight of the polymer 1000 to 32000 g / mol, the polymer constituting the resin material is an isocyanate-terminated prepolymer and a polyfunctional polyol as raw materials. , And preferably 0.1 to 5 parts by weight, more preferably 0.1 to 2.5 parts by weight, based on 100 parts by weight of the isocyanate-terminated prepolymer.

As the chain extender, it is preferable to use a bifunctional chain extender having active hydrogen at both ends. Specifically, ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, 3-methyl1,5-pentanediol, neopentyl glycol, methyloctanediol, Alicyclic diols such as 1,9-nonanediol; alicyclic diols such as 1,4-cyclohexanediol; 1,4-bis (β-hydroxyethoxy) benzene, hydroquinone, resorcin, chlorohydroquinone, bromohydroquinone, Methylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxydiphenylsulfone, 4,4' -Dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, bisphenol A, 1,1-di (4-hydroxyphenyl) cyclohexane, 1,2-bis (4-hydroxyphenoxy) ethane, 1,4-dihydroxynaphthalin, 2, Examples include aromatic diols such as 6-dihydroxynaphthalin. Among these, it is preferable to use 1,4-butanediol. When a chain extender is used, it is preferably contained in an amount of 1 to 5 parts by weight based on 100 parts by weight of the isocyanate-terminated prepolymer.

When the prepolymer method is used, it is preferable to produce a thermosetting polyurethane by mixing a polyfunctional polyol and a chain extender with the isocyanate-terminated prepolymer, in order to optimize the chemically crosslinked structure of the thermosetting polyurethane. In particular, in order to make the intercrosslinking molecular weight of the polymer 1000 to 32000 g / mol, the ratio of the polyfunctional polyol to the chain extender is preferably 0.02 to 5 by weight, preferably 0.02 to 1. It is more preferable to do so.

In order to improve the creep resistance and tire durability of a non-pneumatic tire, in the present invention, it is preferable that the polymer constituting the resin material contains a chemically crosslinked structure, and further, the polymer constituting the resin material. More preferably, the intercrosslinking molecular weight is 1000 to 32000 g / mol. For example, when the polymer is a thermosetting polyurethane, the intercrosslinking molecular weight (Mc) of the polymer can be calculated by the following (Equation 1).
(Mc) = (total amount of thermosetting polyurethane) / (Wt / Mt) (Equation 1)
In (Formula 1), Wt is the molecular weight of the polyfunctional polyol, and Wt is the weight% of the polyfunctional polyol when the total amount of the thermosetting polyurethane is 100% by weight.

In the present invention, the resin material can be reinforced with a granular filler, a metal ring, or the like. Examples of the granular filler include ceramics such as carbon black, silica and alumina, and other inorganic fillers.

Hereinafter, an example of the configuration of the non-pneumatic tire T according to the present invention will be described with reference to the drawings.

FIG. 1 is a front view showing an example of a non-pneumatic tire T. 2A is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 2B is a perspective view showing a part of a non-pneumatic tire. FIG. 3 is an enlarged view of a part of FIG. Here, O indicates the shaft core, and H indicates the tire cross-sectional height.

The non-pneumatic tire T includes a support structure SS that supports a load from the vehicle. The non-pneumatic tire T may be provided with such a support structure SS, and a member corresponding to a tread, a reinforcing layer, and a tread-corresponding member, a reinforcing layer, etc. It may be provided with a member for fitting with an axle or a rim.

In the non-pneumatic tire T illustrated in the present embodiment, as shown in the front view of FIG. 1, the support structure SS has an inner annular portion 1, an outer annular portion 2 concentrically provided on the outer side thereof, and an inner side. The annular portion 1 and the outer annular portion 2 are connected to each other, and a plurality of connecting portions 3 independently provided on the tire circumferential direction CD are provided.

The inner annular portion 1 preferably has a cylindrical shape having a constant thickness from the viewpoint of improving uniformity. Further, it is preferable that the inner peripheral surface of the inner annular portion 1 is provided with irregularities or the like for maintaining the fitability for mounting on the axle or the rim.

The thickness of the inner annular portion 1 is preferably 2 to 10% of the tire cross-sectional height H, preferably 3 to 9%, from the viewpoint of reducing weight and improving durability while sufficiently transmitting force to the connecting portion 3. preferable.

The inner diameter of the inner annular portion 1 is appropriately determined according to the dimensions of the rim and the axle on which the non-pneumatic tire T is mounted. However, assuming a substitute for a general pneumatic tire, 250 to 500 mm is preferable, and 320 to 440 mm is more preferable.

The width of the inner annular portion 1 in the tire width direction is appropriately determined according to the application, the length of the axle, and the like, but when a substitute for a general pneumatic tire is assumed, 100 to 300 mm is preferable, and 120 to 250 mm is preferable. More preferred.

The tensile modulus of the inner annular portion 1 is preferably 5 to 180,000 MPa, more preferably 7 to 50,000 MPa, from the viewpoint of weight reduction, improvement of durability, and wearability while sufficiently transmitting force to the connecting portion 3. The tensile modulus in the present invention is a value calculated from the tensile stress at the time of 10% elongation by performing a tensile test according to JIS K7312.

In the support structure SS in the present invention, at least a part of the connecting portion 3 is made of a resin material, but the inner annular portion 1 and the outer side can be integrally molded when the support structure SS is manufactured. It is preferable that the annular portion 2 and the connecting portion 3 are basically made of the same material except for the reinforcing structure.

In the support structure SS formed of the resin material, at least a part of the inner annular portion 1, the outer annular portion 2, and the connecting portion 3 may be reinforced by reinforcing fibers.

Examples of the reinforcing fibers include reinforcing fibers such as long fibers, short fibers, woven fabrics, and non-woven fabrics. As a form in which the long fibers are used, fibers arranged in the tire width direction and fibers arranged in the tire circumferential direction are used. It is preferable to use a net-like fiber aggregate composed of.

Examples of the types of reinforcing fibers include rayon cords, polyamide cords such as nylon-6 and 6, polyester cords such as polyethylene terephthalate, aramid cords, glass fiber cords, carbon fibers, and steel cords.

The shape of the outer annular portion 2 is preferably a cylindrical shape having a constant thickness from the viewpoint of improving uniformity. The thickness of the outer annular portion 2 is preferably 2 to 20% of the tire cross-sectional height H, preferably 10 to 15%, from the viewpoint of reducing weight and improving durability while sufficiently transmitting the force from the connecting portion 3. More preferred.

The inner diameter of the outer annular portion 2 is appropriately determined according to the intended use and the like. However, assuming a substitute for a general pneumatic tire, 420 to 750 mm is preferable, and 470 to 680 mm is more preferable.

The width of the outer annular portion 2 in the tire width direction is appropriately determined depending on the application and the like, but is preferably 100 to 300 mm, more preferably 120 to 250 mm, assuming a substitute for a general pneumatic tire.

The tensile modulus of the outer annular portion 2 can be set to the same extent as that of the inner annular portion 1 when the reinforcing layer 7 is provided on the outer periphery of the outer annular portion 2 as shown in FIG. When such a reinforcing layer 7 is not provided, 5 to 180,000 MPa is preferable, and 7 to 50,000 MPa is more preferable, from the viewpoint of sufficiently transmitting the force from the connecting portion 3 while reducing the weight and improving the durability.

When increasing the tensile modulus of the outer annular portion 2, a fiber reinforcing material in which an elastic material is reinforced with fibers or the like is preferable. By reinforcing the outer annular portion 2 with reinforcing fibers, the adhesion between the outer annular portion 2 and the belt layer or the like becomes sufficient.

The connecting portion 3 connects the inner annular portion 1 and the outer annular portion 2, and a plurality of connecting portions 3 are provided on the tire circumferential direction CD so as to be independent of each other by providing an appropriate distance between the connecting portions 3. Is preferable.

In the present embodiment, the plurality of connecting portions 3 are configured such that the first connecting portion 31 and the second connecting portion 32 are arranged along the tire circumferential direction CD. At this time, it is preferable that the first connecting portion 31 and the second connecting portion 32 are alternately arranged along the tire circumferential direction CD. As a result, the distribution of contact pressure when the tire rolls can be made smaller.

Further, the pitch p of the tire circumferential direction CD between the first connecting portion 31 and the second connecting portion 32 is preferably constant from the viewpoint of improving uniformity. The pitch p is preferably 0 to 10 mm, more preferably 0 to 5 mm. If the pitch p is larger than 10 mm, the ground pressure becomes non-uniform, which may cause noise to increase.

In the present embodiment, the first connecting portion 31 extends from one side WD1 in the tire width direction of the inner annular portion 1 toward the other side WD2 in the tire width direction of the outer annular portion 2. On the other hand, the second connecting portion 32 extends from the other side WD2 in the tire width direction of the inner annular portion 1 toward the one side WD1 in the tire width direction of the outer annular portion 2. That is, the adjacent first connecting portion 31 and the second connecting portion 32 are arranged in a substantially X shape when viewed from the tire circumferential direction CD.

As shown in FIG. 2A, the first connecting portion 31 and the second connecting portion 32 viewed from the tire circumferential direction CD preferably have a shape symmetrical with respect to the tire equatorial plane C. Therefore, the first connecting portion 31 will be mainly described below.

In the present embodiment, the first connecting portion 31 has a long plate shape extending from the inner annular portion 1 to the outer annular portion 2. In the first connecting portion 31, the plate thickness t is smaller than the plate width w, and the plate thickness direction PT faces the tire circumferential direction CD. That is, the first connecting portion 31 has a plate shape extending in the tire radial direction RD and the tire width direction WD. By forming the first connecting portion 31 and the second connecting portion 32 into such a long plate shape, even if the plate thickness t is reduced, the plate width w can be set wide to form the first connecting portion 31 and the second connecting portion 32. Since the second connecting portion 32 can obtain desired rigidity, durability can be improved. Further, by increasing the number of the first connecting portion 31 and the second connecting portion 32 while reducing the plate thickness t, the rigidity of the entire tire is maintained and the gap between the connecting portions adjacent to the CD in the tire circumferential direction is reduced. Therefore, it is possible to reduce the distribution of contact pressure when the tire rolls.

The plate thickness t of the first connecting portion 31 may be constant along the longitudinal direction PL, but as shown in FIG. 3, the plate thickness t of the first connecting portion 31 is from the inner annular portion 1 to the outer annular portion 2. It is preferable that the number gradually increases toward. In this case, the plate thickness t at the outer end of the first connecting portion 31 in the tire radial direction is set to be smaller than the plate width w.

The plate thickness t is preferably 8 to 30 mm, more preferably 10 to 25 mm, from the viewpoint of reducing the weight and improving the durability while sufficiently transmitting the force from the inner annular portion 1 and the outer annular portion 2.

FIG. 4 shows only the first connecting portion 31 of FIG. 2A. The first connecting portion 31 is composed of an inner end portion 3a in the tire radial direction, a central portion 3b in the tire radial direction, and an outer end portion 3c in the tire radial direction. Assuming that the tire radial height of the first connecting portion 31 is h, the tire radial center portion 3b is ± 15 to h of h from the tire radial height center 31c of the first connecting portion 31 toward the tire radial RD. It is in the range of 35%.

At the central portion 3b in the tire radial direction, the plate width wb in the tire width direction WD is constant. On the other hand, the inner end portion 3a in the tire radial direction is provided with an inner peripheral side reinforcing portion 33 that is larger than the plate width wb of the central portion 3b in the tire radial direction. As a result, at the inner end portion 3a in the tire radial direction, the plate width wa gradually increases toward the inside of the tire radial direction RD. The first connecting portion 31 viewed from the tire circumferential direction has an inner peripheral side reinforcing portion 33 at the inner end portion 3a in the tire radial direction, which is wider than the plate width wb of the central portion 3b in the tire radial direction. It is possible to reduce the stress concentration at the inner end portion 3a in the tire radial direction in which the 1 connecting portion 31 is coupled to the inner annular portion 1, and the durability can be further improved.

The inner peripheral side reinforcing portions 33 are provided on both sides of the first connecting portion 31 in the tire width direction WD, respectively. The inner peripheral side reinforcing portion 33 inside the tire width direction WD reaches the tire equatorial plane C. Further, the inner peripheral side reinforcing portion 33 on the outer side of the tire width direction WD reaches the end portion of the non-pneumatic tire T on one side WD1 in the tire width direction.

The surface area A of the tire radial inner end portion 3a including the inner peripheral side reinforcing portion 33 is 0.5 times or more the surface area B of the tire radial central portion 3b. If the surface area A is smaller than 0.5 times the surface area B, stress concentration at the inner end portion 3a in the radial direction of the tire may become a problem.

In the present embodiment, the tire radial outer end portion 3c is provided with an outer peripheral side reinforcing portion 34 that is larger than the plate width wb of the tire radial central portion 3b. As a result, at the outer end portion 3c in the tire radial direction, the plate width wc gradually increases toward the outside of the tire radial direction RD. The first connecting portion 31 viewed from the tire circumferential direction has a reinforcing portion 34 on the outer peripheral side which is wider than the plate width wb of the central portion 3b in the tire radial direction at the outer end portion 3c in the tire radial direction. The stress concentration at the tire radial outer end 3c where the connecting portion 31 is coupled to the outer annular portion 2 can be reduced, and the durability can be further improved.

In the present embodiment, the outer peripheral side reinforcing portions 34 are provided on both sides of the first connecting portion 31 in the tire width direction WD, respectively. The outer peripheral side reinforcing portion 34 inside the tire width direction WD reaches the tire equatorial plane C. Further, the outer peripheral side reinforcing portion 34 of the tire width direction WD reaches the end portion of the non-pneumatic tire T on the other side WD2 in the tire width direction.

In the present embodiment, the surface area A'of the tire radial outer end portion 3c including the outer peripheral side reinforcing portion 34 is 0.5 times or more the surface area B of the tire radial central portion 3b. If the surface area A'is smaller than 0.5 times the surface area B, stress concentration at the tire radial outer end portion 3c may become a problem. Further, in the present embodiment, the surface area A'of the tire radial outer end portion 3c is equal to the surface area A of the tire radial inner end portion 3a.

In the present embodiment, the total surface area A of the tire radial inner end portion 3a and the surface area A'of the tire radial outer end portion 3c is equal to or greater than the surface area B of the tire radial central portion 3b. As a result, stress concentration at the tire radial inner end 3a and the tire radial outer end 3c can be effectively reduced. Considering the balance between durability and ride quality, the sum of the surface area A of the tire radial inner end 3a and the surface area A'of the tire radial outer end 3c is 2 of the surface area of the tire radial center 3b. It is preferably twice or less.

In the present embodiment, the inner peripheral side reinforcing portion 33 and the outer peripheral side reinforcing portion 34 both have an arc shape. The arcs of the inner peripheral side reinforcing portion 33 and the outer peripheral side reinforcing portion 34 are convex toward the first connecting portion 31 side. The radius of curvature of the arc is preferably 5 to 200 mm.

The plate width w is preferably 5 to 25 mm, more preferably 10 to 20 mm, from the viewpoint of reducing the weight and improving the durability while sufficiently transmitting the force from the inner annular portion 1 and the outer annular portion 2. Further, the plate width w is preferably 110% or more, more preferably 115% or more of the plate thickness t from the viewpoint of improving the durability and reducing the dispersion of the ground pressure.

The plate width wa of the inner end portion 3a in the tire radial direction is preferably 30 to 140 mm, more preferably 70 to 140 mm. The plate width wb of the central portion 3b in the tire radial direction is preferably 5 to 70 mm, more preferably 15 to 35 mm. The plate width wc of the central portion 3c in the tire radial direction is preferably 30 to 140 mm, more preferably 70 to 140 mm.

The number of connecting portions 3 is preferably 80 to 300, more preferably 100 to 200, from the viewpoint of reducing weight, improving power transmission, and improving durability while sufficiently supporting the load from the vehicle. FIG. 1 shows an example in which 50 first connecting portions 31 and 50 second connecting portions 32 are provided.

The tensile modulus of the connecting portion 3 is preferably 5 to 180,000 MPa from the viewpoint of reducing the weight, improving the durability, and improving the lateral rigidity while sufficiently transmitting the force from the inner annular portion 1 and the outer annular portion 2. ~ 50,000 MPa is more preferable. When increasing the tensile modulus of the connecting portion 3, a fiber reinforcing material in which an elastic material is reinforced with fibers or the like is preferable.

In the present embodiment, as shown in FIG. 1, an example is shown in which a reinforcing layer 7 for reinforcing bending deformation of the outer annular portion 2 is provided on the outside of the outer annular portion 2 of the support structure SS. Further, in the present embodiment, as shown in FIG. 1, an example in which the tread 8 is provided on the outer side of the reinforcing layer 7 is shown. As the reinforcing layer 7 and the tread 8, it is possible to provide the same one as the belt layer of the conventional pneumatic tire. The tread 8 may be made of resin. Further, as the tread pattern, it is possible to provide a pattern similar to that of a conventional pneumatic tire.

In the present invention, it is preferable to further arrange a widthwise reinforcing layer for increasing the rigidity in the tire width direction between the tire radial outer end of the connecting portion 3 and the tread 8. As a result, buckling of the outer annular portion 2 at the central portion in the tire width direction can be suppressed, and the durability of the connecting portion 3 can be further improved. The widthwise reinforcing layer is embedded in the outer annular portion 2 or arranged outside the outer annular portion 2. Examples of the width direction reinforcing layer include those in which fiber reinforced plastic cords such as steel cords, CFRP, and GFRP are arranged substantially parallel to the tire width direction, cylindrical metal rings, and high modulus resin rings. Will be done.

[Other Embodiments]
(1) In the above-described embodiment, the surface area A'of the tire radial outer end 3c is equal to the surface area A of the tire radial inner end 3a, but preferably the tire radial outer end 3c. The surface area A'is equal to or greater than the surface area A of the inner end portion 3a in the radial direction of the tire. As a result, the ground contact pressure when the outer end portion 3c in the tire radial direction comes into contact with the ground can be reduced, and the ground pressure distribution becomes small, so that the riding comfort and durability can be improved.

In the example shown in FIG. 5, the outer peripheral side reinforcing portion 34 inside the tire width direction WD reaches the end portion of the outer annular portion 2 on one side WD1 in the tire width direction beyond the tire equatorial plane C. As a result, the tire radial outer end portion 3c of the first connecting portion 31 is coupled to the outer annular portion 2 over the entire tire width direction WD. The outer peripheral side reinforcing portion 34 inside the tire width direction WD does not necessarily have to reach the end portion of the outer annular portion 2 on one side WD1 in the tire width direction.

(2) Further, as shown in FIG. 6, the inner peripheral side reinforcing portion 33 inside the tire width direction WD reaches the end portion of the inner annular portion 1 on the other side WD2 in the tire width direction beyond the tire equatorial plane C. You may do so. The inner peripheral side reinforcing portion 33 inside the tire width direction WD does not necessarily have to reach the end portion of the inner annular portion 1 on the other side WD2 in the tire width direction.

(3) In the above-described embodiment, the support structure SS includes an inner annular portion 1, an outer annular portion 2, and a plurality of connecting portions 3, but the inner annular portion 1 and the outer annular portion 2 are used. An intermediate annular portion provided concentrically with these may be provided between the two.

(4) In the above-described embodiment, an example is shown in which the first connecting portion 31 and the second connecting portion 32 adjacent to each other in the support structure SS are arranged in a substantially X shape when viewed from the tire circumferential direction CD. However, the two adjacent connecting portions may have the same shape when viewed from the tire circumferential direction CD.

Hereinafter, examples and the like that specifically show the configuration and effects of the present invention will be described. The evaluation items in the examples and the like were measured as follows.

(1) Degree of swelling of resin material The resin material is immersed in N, N-dimethylformamide (DMF) at 80 ° C. for 1 week, and the rate of increase in weight after immersion (after swelling) with respect to the weight of the resin material before immersion is measured by weight. Calculated in%.

(2) Tire creep resistance A 70 mm wide, φ280 lab tire equipped with 40 2 mm thick spokes is manufactured, a constant load is applied to the lab tire, and the tire is left for a whole day and night, and then the residual deformation amount is measured. The permanent deformation rate was measured. The lower the permanent deformation rate of a tire, the better the creep resistance of the tire. The results are shown in Table 1.

(3) Tire Durability A 70 mm wide, φ280 lab tire equipped with 40 2 mm thick spokes was manufactured, and measured by a drum tester in accordance with FMVSS109 as follows. The test speed was kept constant at 80 km / h, and the mileage until the failure occurred was measured while applying a load divided into four steps gradually increasing. It is shown as an index when the mileage in Comparative Example 1 is 100, and the larger this value is, the better the durability is.

Example 1
100% by weight of polytetramethyrane glycol (manufactured by Mitsubishi Chemical Corporation, PTMG1000 (number average molecular weight 1000, number of functional groups 2)) was placed in the reaction vessel, dehydrated under reduced pressure for 1 hour, and the inside of the reaction vessel was replaced with nitrogen. -29% by weight of phenylenedi isocyanate (PPDI) was added and reacted for 6 hours while maintaining the temperature in the reaction vessel at 90 ° C. to produce an isocyanate-terminated prepolymer.

Next, 11.8 parts by weight of polycarbonate diol (PCD (number average molecular weight 1000, number of functional groups 2) manufactured by Asahi Kasei Co., Ltd.) was added to 100 parts by weight of the isocyanate-terminated prepolymer, and trimethylolpropane (TMP) was used as a polyfunctional polyol. 0.49 parts by weight and 3.89 parts by weight of 1,4-butanediol (1,4-BD) as a chain extender were added, and the mixture was mixed and defoamed to prepare a mixed solution. Such a mixed solution was added to the isocyanate-terminated prepolymer produced above, mixed and defoamed with a hybrid mixer (manufactured by Kurabou Co., Ltd.), and cast into a mold for molding the support structure SS shown in FIG. 1 and the like. Then, it was cured at 130 degreeC for 16 hours, and the support structure SS was obtained. A reinforcing layer 7 and a tread 8 were provided on the indicated structure, and a non-pneumatic tire T having the shape shown in FIG. 1 was manufactured.

Examples 2-3 and Comparative Example 2
The support structure SS and the non-pneumatic tire T were manufactured in the same manner as in Example 1 except that the blending amounts of TMP and 1,4-BD in the mixed solution were changed to the amounts shown in Table 1.

Comparative Example 1
The support structure SS and the non-pneumatic tire T were produced in the same manner as in Example 1 except that TMP was not blended in the mixed solution and only PCD and 1,4-BD were blended.

1 Inner annular part 2 Outer annular part 3 Connecting part 3a Tire radial inner end 3b Tire radial center 3c Tire radial outer end 31 First connecting 32 Second connecting SS Support structure T Non-pneumatic tire CD Tire circumference direction WD Tire width direction RD Tire radial direction WD1 Tire width direction One side WD2 Tire width direction The other side t Plate thickness w Plate width A Tire radial inner end surface area A'Tire radial outer end surface area B Tire Radial central surface area

Claims (4)

In non-pneumatic tires with a support structure that supports the load from the vehicle
The support structure is provided in the tire circumferential direction by connecting the inner annular portion, the outer annular portion concentrically provided on the outer side of the inner annular portion, the inner annular portion and the outer annular portion. With multiple connecting parts
At least a part of the connecting portion is made of a resin material.
The polymer constituting the resin material contains a chemically crosslinked structure.
The chemically crosslinked structure of the polymer constituting the resin material is derived from the polyfunctional polyol.
The resin material is, 80 ° C. of N, the degree of swelling after 1 week immersion N- dimethylformamide is Ri 15-70 wt% der,
A non-pneumatic tire having a molecular weight between crosslinks of a polymer constituting the resin material of 1000 to 19000 g / mol. The non-pneumatic tire according to claim 1, wherein the polymer constituting the resin material is a thermosetting polyurethane. The polymer constituting the resin material contains at least an isocyanate-terminated prepolymer and a polyfunctional polyol as raw materials, and contains 0.1 to 5 parts by weight of the polyfunctional polyol with respect to 100 parts by weight of the isocyanate-terminated prepolymer. The non-pneumatic tire according to claim 1 or 2. The polymer constituting the resin material contains a chain extender as a raw material, and the ratio of the polyfunctional polyol to the chain extender ((polyfunctional polyol) / (chain extender)) is 0.02 by weight. The non-pneumatic tire according to any one of claims 1 to 3, wherein the tire is a non-pneumatic tire.

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