JP5921364B2 - Non-pneumatic tire - Google Patents

Description

  The present invention relates to a non-pneumatic tire including an inner annular portion, an outer annular portion provided concentrically on the outer side of the inner annular portion, and a plurality of connecting portions that connect the inner annular portion and the outer annular portion ( non-pnematic tire).

  The pneumatic tire has a load supporting function, a shock absorbing ability from the ground contact surface, and a transmission ability (acceleration, stop, change of direction) such as power. For this reason, many vehicles, particularly bicycles, motorcycles, automobiles, It is used in trucks.

  In particular, these capabilities greatly contributed to the development of automobiles and other motor vehicles. Furthermore, the impact absorbing ability of pneumatic tires is useful for medical equipment and electronic equipment transport carts and other applications.

  Conventional non-pneumatic tires include, for example, solid tires, spring tires, cushion tires, and the like, but do not have the superior performance of pneumatic tires. For example, solid tires and cushion tires support the load by compressing the contact portion, but this type of tire is heavy and stiff, and does not have the ability to absorb shock like a pneumatic tire. Further, in the non-pneumatic tire, it is possible to improve the cushioning property by increasing the elasticity, but there is a problem that the load supporting ability or the durability as the pneumatic tire has is deteriorated.

  Therefore, in Patent Document 1 below, for the purpose of developing a non-pneumatic tire having the same operating characteristics as a pneumatic tire, a reinforced annular band that supports a load applied to the tire, and the reinforced annular band, Non-pneumatic tires have been proposed that have a plurality of spokes that transmit load forces by tension with a wheel or hub. This non-pneumatic tire is free from air leakage unlike a pneumatic tire, and has no weight problem as a solid tire.

  Patent Document 2 below has an outer peripheral ring and an inner peripheral ring made of an elastic material arranged concentrically, and a spoke material made of an elastic material is connected to both the wheels, and The spoke member is formed as a pair of spoke members that are bent in opposite directions in the tire circumferential direction when a compressive force in the tire radial direction is applied to the gap between the outer ring and the inner ring, A non-pneumatic tire is described in which a connecting member made of an elastic material that suppresses bending in the opposite direction is provided between the pair of spoke members. In this non-pneumatic tire, the pair of spoke materials bend in opposite directions in the tire circumferential direction, thereby improving the riding comfort.

  However, these non-pneumatic tires have a greater impact when stepping down than a pneumatic tire having the same diameter and rigidity. This is because pneumatic tires have good shock absorption performance due to compression / extension in all directions of the air enclosed in the tire, while non-pneumatic tires have such good shock absorption performance. It is because it does not have.

  By the way, since the transmission ability (acceleration, stop, direction change) of power and the like is affected by the ground contact area of the tire, it is preferable that the non-pneumatic tire has a configuration capable of securing a sufficient ground contact area. Specifically, a reduction in the contact area may lead to a deterioration in the stopping performance of the vehicle and may cause an accident.

Special Table 2005-500932 Publication JP 2007-112243 A

  Accordingly, an object of the present invention is to provide a non-pneumatic tire that can improve shock absorption and can secure a sufficient contact area.

The above object can be achieved by the present invention as described below.
That is, the non-pneumatic tire of the present invention includes an inner annular portion, an outer annular portion provided concentrically on the outer side of the inner annular portion, and a plurality of connecting portions that connect the inner annular portion and the outer annular portion. A non-pneumatic tire comprising:
The outer annular portion has a tread layer disposed on the outermost side, and a reinforcing layer disposed on the inner side of the tread layer and having higher rigidity than the tread layer,
The tread surface of the tread layer is provided with a curvature that is convex outward in the tire radial direction in the tire meridian cross section,
The reinforcing layer is divided into a high-rigidity region at both ends in the tire width direction and a low-rigidity region having a lower rigidity than the high-rigidity region at the center in the tire width direction.

  The non-pneumatic tire includes an inner annular portion, an outer annular portion provided concentrically outside the inner annular portion, and a plurality of connecting portions that connect the inner annular portion and the outer annular portion. The book connecting parts are compressed to support the load, and impacts such as when descending a step tend to be attenuated by these several connecting parts. In the non-pneumatic tire of the present invention, since the rigidity of the outer annular portion is increased by having the reinforcing layer, the connecting portion on the opposite side of the ground contact surface is also pulled to support the load with respect to the tire axis. That is, the load is supported not only by the compression of the connecting portion on the ground plane side but also by the extension of the connecting portion on the reverse side of the ground plane. As a result, not only the connecting portion on the ground plane side but also the connecting portion on the reverse side of the ground plane can be subjected to shock attenuation, and the impact absorbability of the entire non-pneumatic tire can be improved. At this time, if the rigidity of the outer annular portion is increased by increasing the rigidity of the tread layer without providing the reinforcing layer, it leads to a decrease in grip performance due to a decrease in the contact area.

  On the other hand, since the deformation of the connecting portion on the grounding surface side is suppressed by providing the reinforcing layer, the grounding area of the tread surface with respect to the road surface tends to decrease. The reinforcing layer of the present invention is divided in the tire width direction, and a central portion in the tire width direction is a low rigidity region. As a result, the load is transmitted and the central portion of the connecting portion in the tire width direction is elastically deformed, so that the ground contact area is increased and a sufficient ground contact area can be secured.

  In the non-pneumatic tire according to the present invention, the width of the low-rigidity region is preferably 10% or more of the tire width. If the width of the low-rigidity region with respect to the tire width is equal to or greater than this value, it is possible to improve shock absorption and secure a sufficient contact area.

  In the non-pneumatic tire according to the present invention, the width of the low-rigidity region is preferably 70% or less of the tire width. If the width of the low-rigidity area with respect to the tire width is less than this value, the center part in the tire width direction of the connecting part can be elastically deformed while suppressing buckling, so that shock absorption can be improved and sufficient grounding is achieved. An area can be secured.

  In the non-pneumatic tire according to the present invention, the tread layer preferably has a tensile elastic modulus of 3 to 50 MPa, and the reinforcing layer preferably has a bending elastic modulus of 1000 MPa or more. According to this configuration, the rigidity of the reinforcing layer can be made higher than that of the tread layer, and the rigidity of the outer annular portion can be increased.

  In the non-pneumatic tire according to the present invention, the high-rigidity region is preferably formed of fiber-reinforced plastic or polyurethane resin. According to this configuration, the bending elastic modulus of the reinforcing layer can be increased, and the rigidity of the entire outer annular portion can be effectively increased.

Front view showing an example of the non-pneumatic tire of the present invention Tire meridian cross-sectional view showing an example of the non-pneumatic tire of the present invention Tire meridian cross-sectional view showing non-pneumatic tires of Comparative Examples 1 and 2

  Hereinafter, embodiments of 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 of the present invention. 2 is a tire meridian cross-sectional view showing an example of the non-pneumatic tire of the present invention, and is a cross-sectional view taken along the line II of FIG. Here, O indicates the axis, WD indicates the tire width direction, W indicates the tire width, and H indicates the tire cross-sectional height.

  The non-pneumatic tire T of the present invention is preferably used in a vehicle that is cornered with a camber, for example. The non-pneumatic tire T of this embodiment includes an inner annular portion 1, an intermediate annular portion 2 provided concentrically on the outer side, an outer annular portion 3 provided concentrically on the outer side, an inner annular portion 1 and an intermediate portion. A plurality of inner connecting portions 4 that connect the annular portion 2 and a plurality of outer connecting portions 5 that connect the outer annular portion 3 and the intermediate annular portion 2 are provided. Although the non-pneumatic tire T of the present embodiment includes the intermediate annular portion 2, the intermediate annular portion 2 is not always necessary, the intermediate annular portion 2 is not provided, and the inner connecting portion 4 and the outer connecting portion 5 are continuous. One connecting portion may be configured. In this case, the non-pneumatic tire T includes an inner annular portion 1, an outer annular portion 3 provided concentrically outside the inner annular portion 1, and a plurality of connections that connect the inner annular portion 1 and the outer annular portion 3. It becomes the composition provided with a part.

  The inner annular portion 1 is preferably a cylindrical shape having a constant thickness from the viewpoint of improving uniformity. Moreover, it is preferable to provide the inner peripheral surface of the inner annular portion 1 with irregularities or the like for maintaining fitting properties for mounting with an axle or a rim.

  The thickness of the inner annular portion 1 is preferably 6 to 30%, and 10 to 20% of the tire cross-section height H from the viewpoint of reducing weight and improving durability while sufficiently transmitting force to the inner connecting portion 4. More preferred.

  An inner diameter of the inner annular portion 1 is appropriately determined in accordance with a rim on which the non-pneumatic tire T is mounted, a size of an axle, and the like. However, in the present embodiment, the inner annular portion 1 is provided with an inner diameter of the inner annular portion 1. It is possible to make it smaller. The inner annular portion 1 has an inner diameter of preferably 50 to 560 mm, and more preferably 80 to 200 mm.

  Although the width | variety of the tire width direction WD of the inner side annular part 1 is suitably determined according to a use, the length of an axle shaft, etc., 30-100 mm is preferable and 40-80 mm is more preferable.

  The tensile modulus of the inner annular portion 1 is preferably from 1 to 180000 MPa, more preferably from 1 to 50000 MPa, from the viewpoint of reducing weight, improving durability, and wearing properties while sufficiently transmitting force to the inner connecting portion 4. In addition, the tensile modulus in this embodiment is a value of a tensile stress when the tensile test is performed according to JIS K7312 and the elongation is 10%.

  The intermediate annular portion 2 is preferably a cylindrical shape with a constant thickness from the viewpoint of improving uniformity, but may be a polygonal cylindrical shape or the like.

  The thickness of the intermediate annular portion 2 is preferably 3 to 10% of the tire cross-section height H from the viewpoint of reducing the weight and improving the durability while sufficiently reinforcing the inner connecting portion 4 and the outer connecting portion 5. -9% is more preferable.

  The inner annular portion 2 has an inner diameter that exceeds the inner diameter of the inner annular portion 1 and less than the inner diameter of the outer annular portion 3. However, the inner ring portion 2 has an inner diameter of 20 to a value obtained by subtracting the inner ring portion 1 from the inner ring portion 3 from the viewpoint of improving the reinforcing effect of the inner connecting portion 4 and the outer connecting portion 5. The value of 80% is preferably the inner diameter added to the inner diameter of the inner annular portion 1, and the value of 30 to 60% is more preferably the inner diameter added to the inner diameter of the inner annular portion 1.

  The width of the intermediate annular portion 2 in the tire width direction WD is appropriately determined according to the application and the like, but is preferably 30 to 100 mm, and more preferably 40 to 80 mm.

  The tensile modulus of the intermediate annular portion 2 is preferably 1 to 180000 MPa, and more preferably 1 to 50000 MPa.

  The outer annular portion 3 has a cylindrical shape whose thickness changes in the tire width direction WD. The outer annular portion 3 includes a tread layer 31 disposed on the outermost side and a reinforcing layer 32 disposed on the inner side of the tread layer 31 and having higher rigidity than the tread layer 31. Further, the outer annular portion 3 preferably has a bonding layer 33 formed of the same material as that of the outer connecting portion 5 inside the reinforcing layer 32. Thereby, the intensity | strength in the junction part of the outer side annular part 3 and the outer side connection part 5 increases, and durability improves.

  As shown in FIG. 2, the tread surface of the tread layer 31 has a curvature that is convex outward in the tire radial direction in the tire meridian cross section, and extends from the center in the tire width direction WD toward both ends. It has a circular arc shape with a gradually decreasing outer diameter. Since the curvature of the tread surface of the tread layer 31 is provided, the ground contact area is not too small even when cornering with a camber, and the variation of the ground contact area between straight traveling and cornering is reduced. . The radius of curvature R of the tread surface of the tread layer 31 is preferably 40 to 100 mm, and more preferably 40 to 65 mm. When the curvature radius R is smaller than 40 mm, the ground contact area at the time of camber becomes excessive, and the grip performance increases rapidly, resulting in a situation close to a sudden stop. Moreover, when the curvature radius R is larger than 100 mm, the ground contact area at the time of camber becomes too small, and the grip performance is drastically lowered, so that slip occurs. The tread surface of the tread layer 31 can be provided with the same pattern as a conventional pneumatic tire as a tread pattern.

  The reinforcing layer 32 has a rectangular shape in the tire meridian cross section. The reinforcing layer 32 is divided into a high rigidity region 321 at both ends in the tire width direction and a low rigidity region 322 at the center in the tire width direction.

  The width WL of the low rigidity region 322 is preferably 10% or more of the tire width W. If the width WL of the low-rigidity region 322 is smaller than 10% of the tire width W, the impact absorbability cannot be improved so much and the contact area is insufficient. On the other hand, the width WL of the low rigidity region 322 is preferably 70% or less of the tire width W. When the width WL of the low-rigidity region 322 is greater than 70% of the tire width W, buckling is likely to occur in which the connecting portion (outer connecting portion 5) is abnormally deformed.

  The rigidity of the low rigidity region 322 is lower than that of the high rigidity region 321. Further, the high rigidity region 321 has higher rigidity than the tread layer 31. Thereby, the reinforcement layer 32 is higher in rigidity than the tread layer 31 as a whole.

  The thickness of the reinforcing layer 32 in the tire radial direction is preferably 1 mm or more from the viewpoint of increasing the rigidity of the outer annular portion 3. The thickness of the reinforcing layer 32 is preferably equal to or less than the thickness at both ends in the tire width direction of the outer annular portion 3 so that the outer peripheral surface of the outer annular portion 3 becomes the tread layer 31. Specifically, the thickness is 4 mm or less. Is preferred. When the bonding layer 33 is provided, the thickness of the bonding layer 33 in the tire radial direction is preferably 1 mm or more from the viewpoint of increasing the adhesive strength with the reinforcing layer 32.

  The tensile elastic modulus of the tread layer 31 is 3 to 50 MPa, preferably 5 to 25 MPa. In addition, the tensile elasticity modulus in this invention is a proportionality constant between the stress and elongation at the time of 5-10% elongation when a tensile test is performed according to JIS K7312.

  The bending elastic modulus of the reinforcing layer 32 is higher than that of the tread layer 31, preferably 1000 MPa or more, and more preferably 2000 MPa or more. When the bending elastic modulus of the reinforcing layer 32 is 1000 MPa or more, the rigidity of the outer annular portion 3 can be effectively increased. The flexural modulus of the reinforcing layer 32 is preferably 120,000 MPa or less, and more preferably 100000 MPa or less. In addition, the bending elastic modulus in this invention is a proportionality constant between the stress at the time of a 0.05-0.25% distortion, when a bending test is done according to JISK7171.

  The high-rigidity region 321 is preferably molded from fiber reinforced plastic (FRP) or polyurethane resin. Examples of the fiber reinforced plastic include glass fiber reinforced plastic and carbon fiber reinforced plastic. The high-rigidity region 321 made of carbon fiber reinforced plastic can be easily formed by using a sheet-like intermediate member obtained by impregnating a cloth (woven fabric) of carbon fiber (carbon fiber) with a thermosetting resin. The orientation direction of the carbon fibers is preferably the tire width direction and the tire circumferential direction. Note that the low-rigidity region 322 only needs to be lower in rigidity than the high-rigidity region 321, and may be formed of the same material as the tread layer 31. The tensile modulus of elasticity of the low-rigidity region 322 is only required to be higher than that of the tread layer 31 and is preferably 3 to 50 MPa.

  Although the internal diameter of the outer side annular part 3 is suitably determined according to the use etc., for example, 100-600 mm is preferable and 120-300 mm is more preferable.

  Although the width | variety of the tire width direction WD of the outer side annular part 3 is suitably determined according to a use etc., 30-100 mm is preferable and 40-80 mm is more preferable.

  The tensile modulus of the outer annular portion 3 is preferably 1 to 180000 MPa, and more preferably 1 to 50000 MPa.

  The inner connecting portion 4 connects the inner annular portion 1 and the intermediate annular portion 2, and a plurality of inner connecting portions 4 are provided so as to be independent from each other in the tire circumferential direction, for example, by providing an appropriate interval therebetween. The inner connecting portion 4 is preferably provided regularly in the tire circumferential direction from the viewpoint of improving uniformity.

  As the number of the inner connecting portions 4 provided over the entire circumference (when a plurality of inner connecting portions 4 are provided in the tire width direction WD, it is counted as one), while sufficiently supporting the load from the vehicle, weight reduction, improvement of power transmission, From the viewpoint of improving durability, 20 to 60 are preferable, and 20 to 50 are more preferable. FIG. 1 shows an example in which 30 inner connecting portions 4 are provided.

  Examples of the shape of each inner connecting portion 4 include a plate-like body and a columnar body. In this embodiment, an example of a plate-like body is shown. These inner connection parts 4 are extended in the tire radial direction or the direction inclined from the tire radial direction in the front sectional view. In the present invention, from the viewpoint of improving the durability by increasing the break point and making it difficult to change the rigidity, the extending direction of the inner connecting portion 4 is preferably within ± 30 ° in the tire radial direction in the front sectional view. The tire radial direction is more preferably within ± 15 °. FIG. 1 shows an example in which the inner connecting portion 4 is extended in the tire radial direction.

  The thickness of the inner connecting portion 4 is preferably 3 to 12% of the tire cross-sectional height H 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. 4 to 10% is more preferable.

  The tensile modulus of the inner connecting portion 4 is preferably 1 to 50 MPa, more preferably 1 to 30 MPa from the viewpoint of reducing weight, improving durability, and improving lateral rigidity while sufficiently transmitting the force from the inner annular portion 1. preferable.

  The tensile elastic modulus of the inner connecting portion 4 is preferably 15 MPa or less, more preferably 10 MPa or less, from the viewpoint of improving impact absorption.

  The outer connecting portion 5 connects the outer annular portion 3 and the intermediate annular portion 2, and a plurality of outer connecting portions 5 are provided so that each is independent in the tire circumferential direction, for example, by providing an appropriate interval therebetween. The outer connecting portion 5 is preferably provided regularly in the tire circumferential direction from the viewpoint of improving uniformity.

  In addition, the outer side connection part 5 and the inner side connection part 4 may be provided in the same position of a perimeter, and may be provided in a different position. That is, the outer connecting portion 5 and the inner connecting portion 4 do not necessarily extend so as to be continuous in the same direction as shown in FIG.

  As the number of outer connecting portions 5 provided over the entire circumference (when one is provided in the tire width direction WD, it is counted as one), while sufficiently supporting the load from the vehicle, weight reduction, improvement of power transmission, From the viewpoint of improving durability, 20 to 60 are preferable, and 20 to 50 are more preferable. FIG. 1 shows an example in which 30 outer connecting parts 5 are provided in the same manner as the inner connecting part 4. In addition, the number of the outer side connection parts 5 and the number of the inner side connection parts 4 do not necessarily need to be the same, and you may provide more outer side connection parts 5 than the inner side connection parts 4. FIG.

  Examples of the shape of each outer connecting portion 5 include a plate-like body and a columnar body. In this embodiment, an example of a plate-like body is shown. These outer connecting portions 5 extend in a tire radial direction or a direction inclined from the tire radial direction in a front sectional view. In the present invention, from the viewpoint of improving the durability by increasing the break point and making it difficult to change the rigidity, the extending direction of the outer connecting portion 5 is preferably within ± 30 ° in the tire radial direction in the front sectional view. The tire radial direction is more preferably within ± 15 °. FIG. 1 shows an example in which the outer connecting portion 5 is extended in the tire radial direction.

  The thickness of the outer connecting portion 5 is preferably 3 to 12% of the tire cross-section height H from the viewpoint of reducing weight, improving durability, and improving lateral rigidity while sufficiently transmitting the force from the inner annular portion 1. 4 to 10% is more preferable.

  The tensile modulus of the outer connecting portion 5 is preferably 1 to 50 MPa, more preferably 1 to 30 MPa from the viewpoint of reducing weight, improving durability, and improving lateral rigidity while sufficiently transmitting the force from the inner annular portion 1. preferable.

  The tensile modulus of the outer connecting portion 5 is preferably 15 MPa or less, and more preferably 10 MPa or less, from the viewpoint of improving impact absorption.

  The non-pneumatic tire T is formed of an elastic material. The elastic material in the present invention refers to a material having a tensile modulus calculated from a tensile stress at 10% elongation by a tensile test according to JIS K7312 and 100 MPa or less. The elastic material of the present invention preferably has a tensile modulus of 0.1 to 100 MPa, more preferably 0.1 to 50 MPa, from the viewpoint of imparting adequate rigidity while obtaining sufficient durability. Examples of the elastic material used as the base material include thermoplastic elastomers, crosslinked rubbers, and other resins.

  Examples of the thermoplastic elastomer include polyester elastomer, polyolefin elastomer, polyamide elastomer, polystyrene elastomer, polyvinyl chloride elastomer, polyurethane elastomer and the like. Rubber materials constituting the crosslinked rubber material include natural rubber, styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IIR), nitrile rubber (NBR), hydrogenated nitrile rubber (hydrogenated NBR). And synthetic rubbers such as chloroprene rubber (CR), ethylene propylene rubber (EPDM), fluorine rubber, silicon rubber, acrylic rubber, and urethane rubber. These rubber materials may be used in combination of two or more as required.

  Examples of other resins include thermoplastic resins and thermosetting resins. Examples of the thermoplastic resin include polyethylene resin, polystyrene resin, and polyvinyl chloride resin, and examples of the thermosetting resin include epoxy resin, phenol resin, polyurethane resin, silicon resin, polyimide resin, and melamine resin.

  Of the above elastic materials, at least the tread layer 31 and the connecting portions 4 and 5 are preferably formed of polyurethane resin from the viewpoint of molding / workability and cost, and the high rigidity region 321 of the reinforcing layer 32 is fiber reinforced. It is preferable to mold with plastic (FRP) or polyurethane resin. In addition, as an elastic material, you may use a foaming material, The thing which foamed said thermoplastic elastomer, crosslinked rubber, and other resin can also be used.

  The inner annular portion 1, the intermediate annular portion 2, the outer annular portion 3, the inner connecting portion 4, and the outer connecting portion 5 formed of an elastic material are preferably reinforced by reinforcing fibers.

  Reinforcing fibers include reinforcing fibers such as long fibers, short fibers, woven fabrics, and non-woven fabrics. As a form using long fibers, fibers arranged in the tire width direction WD and fibers arranged in the tire circumferential direction. It is preferable to use a net-like fiber assembly composed of:

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

  In the present invention, in addition to reinforcement using reinforcing fibers, it is possible to perform reinforcement with a granular filler or reinforcement with a metal ring or the like. Examples of the particulate filler include ceramics such as carbon black, silica, and alumina, and other inorganic fillers.

  The non-pneumatic tire T in the present invention is formed of an elastic material. From the viewpoint of enabling integral molding when manufacturing the non-pneumatic tire T, the inner annular portion 1, the intermediate annular portion 2, the outer annular portion 3, The inner connecting portion 4 and the outer connecting portion 5 are preferably made of basically the same material except for the reinforcing structure.

[Other Embodiments]
The cross-sectional shape of the high-rigidity region 321 of the reinforcing layer 32 is not limited to the above-described rectangular shape, for example, a triangle shape that tapers toward the center in the tire width direction, or a fan shape that becomes thinner toward the center in the tire width direction. But you can.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. In addition, the evaluation item in an Example etc. measured as follows.

Impact Absorbability A 50 kg weight was placed on the test tire and allowed to fall freely from a height of 50 mm, and the impact acceleration in the vertical direction applied to the center of the wheel when the tire landed was measured. Measure five times for each sample and use the average as the result. Table 1 shows the measurement results of impact acceleration. It shows that it is excellent in impact absorbability, so that impact acceleration is small.

Ground contact area A load was applied to the test tire in the vertical direction, and the ground contact area of the outer peripheral surface (tread surface) of the outer annular portion at 500 N load was measured. Table 1 shows the measurement results of the contact area.

Presence / absence of buckling When a load was applied to the test tire in the vertical direction and the displacement amount of the tire exceeded 6 mm at a load of 1000 N, it was determined that buckling occurred that abnormally deformed the connecting portion. Table 1 shows the presence or absence of buckling.

Comparative Example 1
A non-pneumatic tire without a reinforcing layer as shown in FIG. The tensile elastic modulus of the connecting portion was 25 MPa. The tensile elastic modulus of the tread layer was 6 MPa, and the other comparative examples and examples were the same.

Comparative Example 2
A non-pneumatic tire provided with a reinforcing layer that is not divided into a high-rigidity region and a low-rigidity region in the tire width direction as shown in FIG. The tensile elastic modulus of the connecting portion was 15 MPa.

Examples 1-7
Examples 1 to 7 are non-pneumatic tires provided with a reinforcing layer in which the width of the low-rigidity region shown in FIG. 2 is 5, 10, 25, 40, 55, 70, and 75% of the tire width, respectively.

  As shown in Table 1, Comparative Example 2 has a smaller impact acceleration than Comparative Example 1, but has a smaller ground contact area. On the other hand, in Examples 1-7, the impact acceleration is smaller than that in Comparative Example 1, and the ground contact area is not as small as in Comparative Example 2. However, in Example 1, since the width of the low-rigidity region is small, the impact acceleration is not so small as compared to Comparative Example 1, and the ground contact area is also small. In Example 7, since the width of the low rigidity region is large, buckling occurs.

DESCRIPTION OF SYMBOLS 1 Inner ring part 2 Middle ring part 3 Outer ring part 4 Inner connection part 5 Outer connection part 31 Tread layer 32 Reinforcement layer 321 High rigidity area 322 Low rigidity area T Non-pneumatic tire W Tire width WL Low rigidity area width WD Tire width direction

Claims (5)

A non-pneumatic tire comprising an inner annular portion, an outer annular portion provided concentrically outside the inner annular portion, and a plurality of connecting portions that connect the inner annular portion and the outer annular portion,
The outer annular portion has a tread layer disposed on the outermost side, and a reinforcing layer disposed on the inner side of the tread layer and having higher rigidity than the tread layer,
The tread surface of the tread layer is provided with a curvature that is convex outward in the tire radial direction in the tire meridian cross section,
The non-pneumatic tire is characterized in that the reinforcing layer is divided into a high-rigidity region at both ends in the tire width direction and a low-rigidity region that is lower in rigidity than the high-rigidity region at the center in the tire width direction.   The non-pneumatic tire according to claim 1, wherein the width of the low rigidity region is 10% or more of the tire width.   The non-pneumatic tire according to claim 1 or 2, wherein the width of the low rigidity region is 70% or less of the tire width.   The non-pneumatic tire according to any one of claims 1 to 3, wherein the tread layer has a tensile elastic modulus of 3 to 50 MPa, and the reinforcing layer has a bending elastic modulus of 1000 MPa or more. The non-pneumatic tire according to any one of claims 1 to 4, wherein the high-rigidity region is formed of fiber reinforced plastic or polyurethane resin.

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