JP5543846B2 - Non-pneumatic tire - Google Patents

Description

  The present invention relates to a non-pneumatic tire provided with a support structure that supports 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 relates to tires.

  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 web spokes that transmit load forces by tension with a wheel or hub. However, since this non-pneumatic tire has a gap between web spokes adjacent to each other in the circumferential direction, the rigidity of the annular band is reduced in the region between the web spokes. The tread part may cause buckling between web spokes.

  As a countermeasure against such buckling, the following Patent Document 2 discloses a non-pneumatic tire in which air is contained in at least a part of a plurality of spaces formed between spokes adjacent in the tire circumferential direction. Have been described.

Special Table 2005-500932 Publication JP 2009-196603 A

  By the way, in a high load region such as when stepping over a step, spoke buckling may occur. When the spokes buckle, bending fatigue due to high strain, abnormal wear due to contact between the spokes, and the like occur, so that the spokes are destroyed at an early stage and the durability of the non-pneumatic tire is lowered. Moreover, there is a problem that the spoke rigidity is drastically lowered due to the buckling of the spoke, and the steering stability is lowered. However, the non-pneumatic tire of Patent Document 2 is configured to disperse the load by the repulsion of the contained air and suppress the buckling of the tread portion, so that the rigidity is insufficient, and the buckling of the spoke in the high load region is insufficient. The suppression effect was not sufficient.

  Accordingly, an object of the present invention is to provide a non-pneumatic tire that can sufficiently suppress the buckling of a spoke even in a high load range and has improved durability and steering stability.

The above object can be achieved by the present invention as described below.
That is, the non-pneumatic tire of the present invention is a non-pneumatic tire provided with a support structure that supports a load from a vehicle, and the support structure is provided concentrically on the inner annular portion and on the outer side of the inner annular portion. A plurality of connecting portions that connect the inner annular portion and the outer annular portion and are independent in the tire circumferential direction, and are separated by the annular portion and the connecting portion. The foamed polyurethane member is respectively disposed on the foamed polyurethane member, and at least a part of the foamed polyurethane member is close to the outer annular portion.

  The non-pneumatic tire of the present invention includes a support structure that supports a load from a vehicle. The support structure includes an annular portion of an inner annular portion and an outer annular portion, and a plurality of connecting portions that connect the inner annular portion and the outer annular portion and are independent in the tire circumferential direction. In the non-pneumatic tire of the present invention, a foamed polyurethane member is disposed in each of the gaps divided by the annular part and the connecting part, and a part of the foamed polyurethane member is at least close to the outer annular part. . Note that the proximity in the present invention means a state in which a part of the foamed polyurethane member is in contact with the outer annular portion or there is a slight gap between the outer annular portion. According to this configuration, the polyurethane foam member has high rigidity and can support a longitudinal load in the tire radial direction even when grounding at the outer annular portion between the adjacent connecting portions. Deformation can be suppressed and buckling of the connecting portion (spoke) can be suppressed. Furthermore, since the foamed polyurethane member is disposed between the adjacent connecting portions, the foamed polyurethane member directly suppresses deformation of the connecting portion (spoke) in the tire circumferential direction and suppresses buckling of the connecting portion (spoke). be able to. As a result, it is possible to provide a non-pneumatic tire that can sufficiently suppress the buckling of spokes even in a high load range and has improved durability and steering stability.

  In the non-pneumatic tire according to the present invention, the polyurethane foam member is in contact with the entire outer peripheral surface of the inner annular portion and is adjacent to a central portion between the adjacent connecting portions on the inner peripheral surface of the outer annular portion. It is preferable.

  When grounding at the position of the central portion between adjacent connecting portions, the outer annular portion is most easily bent. Therefore, according to the said structure, a polyurethane foam member can suppress a deformation | transformation of an outer side annular part effectively, and can fully suppress the buckling of a connection part.

  In the non-pneumatic tire according to the present invention, the cross-sectional shape of the polyurethane foam member viewed from the tire axial direction is a semicircular shape, a semi-elliptical shape, a trapezoidal shape, or a triangular shape that becomes narrower outward in the tire radial direction. Is preferred.

  According to this configuration, since there is a gap between the foamed polyurethane member and the connecting portion, heat generated in the non-pneumatic tire can be easily released to the outside, and heat dissipation is good.

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 Right side view of the non-pneumatic tire of Fig. 1 as seen from the right A view of a non-pneumatic tire T leaning at a camber angle α as seen from the front of the vehicle The front view which shows the non-pneumatic tire of an Example and a comparative example Schematic diagram for explaining the evaluation test method Evaluation results of durability and rolling resistance in Examples and Comparative Examples The graph which shows the result of the rigidity fluctuation test in an Example and a comparative example

  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. FIG. 2 is a tire meridian cross-sectional view showing an example of the non-pneumatic tire of the present invention. FIG. 3 shows a part of a right side view of the non-pneumatic tire of FIG. 1 as viewed from the right. Here, O indicates the shaft core, and H indicates the tire cross-sectional height.

  The non-pneumatic tire T shown in the present embodiment is preferably used in a vehicle that is cornered with a camber. That is, when the vehicle corners, when the vehicle is viewed from the front, the upper part of the non-pneumatic tire T is inclined to the left or right at a camber angle α as shown in FIG. The camber angle α of a normal automobile tire is about 2 degrees at the maximum, but the non-pneumatic tire T shown in the present embodiment can be used for a vehicle that is cornered with a camber of about 8 degrees at the maximum.

  The non-pneumatic tire T includes a support structure SS that supports a load from the vehicle. Furthermore, the non-pneumatic tire T of the present invention includes a tread portion 6 on the outer periphery of the support structure SS. Further, the non-pneumatic tire T of the present invention is characterized in that the polyurethane foam member 8 is provided in the support structure SS.

  As shown in the front view of FIG. 1, the non-pneumatic tire T according to the present embodiment includes an inner annular portion 1, an intermediate annular portion 2 provided concentrically on the outer side thereof, and an outer side thereof. A concentric outer ring part 3, an inner ring part 1, an intermediate ring part 2, a plurality of inner connection parts 4 that are independent in the circumferential direction, an outer ring part 3, and an intermediate ring part 2 And a plurality of outer connecting portions 5 that are independent of each other in the circumferential direction. In this embodiment, the support structure SS includes the intermediate annular portion 2, but the intermediate annular portion 2 is not always necessary, and the intermediate annular portion 2 is not provided, and the inner connecting portion 4 and the outer connecting portion 5 are continuous. However, you may comprise one connection 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.

  The inner annular portion 1 has an inner diameter appropriately determined in accordance with the dimensions of the rim on which the non-pneumatic tire T is mounted and the axle. However, in the present invention, since the intermediate annular portion 2 is provided, the inner annular portion 1 has a larger inner diameter. It can be made smaller. The inner annular portion 1 has an inner diameter of preferably 50 to 560 mm, and more preferably 80 to 200 mm.

  The axial width of the inner annular portion 1 is appropriately determined according to the application, the length of the axle, and the like, but is preferably 30 to 100 mm, and more preferably 40 to 80 mm.

  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. The tensile modulus in the present invention is a value calculated from a tensile stress at 10% elongation by conducting a tensile test according to JIS K7312.

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

  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, a polyurethane resin is preferably used from the viewpoint of moldability / workability and cost. In addition, as an elastic material, you may use a foaming material, and what used said thermoplastic elastomer, crosslinked rubber, and other resin foamed can be used.

  In the support structure SS integrally formed of an elastic material, 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 reinforced with 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 using long fibers, fibers arranged in the tire axial direction 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 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 axial width of the intermediate annular portion 2 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 shape of the outer annular portion 3 is preferably a cylindrical shape with a constant thickness from the viewpoint of improving uniformity. The thickness of the outer annular portion 3 is preferably 2 to 10% of the tire cross-section height H from the viewpoint of reducing the weight and improving the durability while sufficiently transmitting the force from the outer connecting portion 5, and is 2 to 9%. Is more preferable.

  The inner diameter of the outer annular portion 3 is appropriately determined according to its use and the like, but since the intermediate annular portion 2 is provided in the present invention, the inner diameter of the outer annular portion 3 can be made larger. 100-600 mm is preferable and the outer diameter of the outer side annular part 3 has more preferable 120-300 mm.

  The axial width of the outer annular portion 3 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 outer annular portion 3 is preferably 1 to 180000 MPa, more preferably 1 to 50000 MPa, from the viewpoint of reducing the weight and improving the durability while sufficiently transmitting the force from the outer connecting portion 5.

  When the tensile modulus of the outer annular portion 3 is increased, a fiber reinforced material obtained by reinforcing an elastic material with fibers or the like is preferable. By reinforcing the outer annular portion 3 with the reinforcing fiber, the adhesion between the outer annular portion 3 and the tread portion 6 becomes sufficient.

  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 that each is independent in the circumferential direction, for example, by providing an appropriate interval therebetween. The inner connecting portion 4 is preferably provided regularly in the circumferential direction from the viewpoint of improving uniformity.

  As for the number of inner connection parts 4 provided over the entire circumference (when a plurality of inner connection parts 4 are provided in the axial direction, it is counted as one), while supporting the load from the vehicle sufficiently, weight reduction, improvement of power transmission, durability From the viewpoint of improving the quality, 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.

  When the tensile modulus of the inner connecting portion 4 is increased, a fiber reinforced material obtained by reinforcing an elastic material with fibers or the like is preferable.

  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 of them is independent in the circumferential direction, for example, by providing an appropriate interval therebetween. The outer connecting portion 5 is preferably provided regularly in the 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 for the number of outer connecting parts 5 provided over the entire circumference (when a plurality of outer connecting parts 5 are provided in the axial direction, they are counted as one), while supporting the load from the vehicle sufficiently, weight reduction, improvement of power transmission, durability From the viewpoint of improving the quality, 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.

  In order to increase the tensile modulus of the outer connecting portion 5, a fiber reinforced material obtained by reinforcing an elastic material with fibers or the like is preferable.

  In the present embodiment, each outer connecting portion 5 is a plate-like body, and a portion that intersects with the outer annular portion 3 constitutes an intersection line portion 51. The intersection 51 is inclined at an angle θ with respect to the tire width direction as indicated by a broken line in FIG. Further, the adjacent intersecting line portions 51 are independent of each other, and are inclined at an angle θ in opposite directions to the tire width direction. That is, when viewed from the tire radial direction, the outer connecting portion 5 is provided so that two adjacent intersecting line portions 51 have a square shape. When the intersecting line portion 51 is parallel to the tire width direction, there is a difference in the vertical displacement of the tire (vibration width in the vertical direction) between when the ground is directly below the outer connecting portion 5 and when the ground is between the outer connecting portions 5. It becomes larger and leads to a worse ride. On the other hand, when the intersection line portion 51 is inclined with respect to the tire width direction, the tire width direction both end portions 51a of the intersection line portion 51 are close to the tire width direction both end portions 51a of the adjacent intersection line portion 51, Since the interval between the adjacent outer connecting portions 5 is narrowed, the displacement difference is reduced. However, in the present invention, the intersecting line portion 51 does not necessarily have to be inclined with respect to the tire width direction.

  The inclination angle θ of the intersection 51 with respect to the tire width direction is preferably 45 degrees or less. During cornering with a camber, torque in the tire width direction is generated, and if the intersection 51 is inclined in the tire width direction, the durability against the torque in the tire width direction tends to decrease. If θ is greater than 45 degrees, the effect of improving the displacement difference in the vertical direction is high, but the durability in the tire width direction is significantly reduced, which is not preferable.

  The thicknesses of the inner connecting portion 4 and the outer connecting portion 5 are constant in the tire radial direction, but increase in the tire width direction from both end portions 51a toward the central portion 51b as shown in FIG. Yes. In this embodiment, both end portions 51a have a thickness, but the center portion 51b may swell with the thickness of both end portions 51a being zero. However, in this invention, you may make the thickness of the inner side connection part 4 and the outer side connection part 5 constant in a tire width direction.

  The tread portion 6 is provided on the outer periphery of the support structure SS. As shown in FIG. 2, the tread portion 6 has a curvature in the tire width direction. Since the tread portion 6 has a curvature, the ground contact area does not become too small even when cornering with a camber, and the variation of the ground contact area between straight traveling and cornering is reduced. 40-100 mm is preferable and, as for the curvature radius R of the tread part 6, 40-65 mm is more preferable. 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. In the present invention, the tread portion 6 may be parallel to the tire width direction without providing a curvature.

  The tread portion 6 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 include the above-described thermoplastic elastomer, crosslinked rubber, thermoplastic resin, thermosetting resin, and the like. Of the above elastic materials, a polyurethane resin is preferably used from the viewpoint of moldability / workability and cost.

  A pattern similar to that of a conventional pneumatic tire can be provided on the outer surface of the tread portion 6 as a tread pattern.

  A foamed polyurethane member 8 is provided in each gap portion 7 divided by the annular portions of the inner annular portion 1, the intermediate annular portion 2, and the outer annular portion 3, and the coupling portions of the inner coupling portion 4 and the outer coupling portion 5. Each is arranged. The foamed polyurethane member 8 may be provided so as to completely fill the gap 7, but may be provided so as not to be completely filled. However, if the gap 7 is completely filled with the foamed polyurethane member 8, the rigidity becomes too high even in a low load region, so there is a possibility that the shock absorption (such as overstepping performance) during normal running may be reduced. is there.

  The cross-sectional shape of the foamed polyurethane member 8 viewed from the tire axial direction is a semicircular or semielliptical shape that becomes narrower toward the outer side in the tire radial direction. However, the cross-sectional shape of the foamed polyurethane member 8 is not limited to a semicircular shape and a semi-elliptical shape, and may be a trapezoidal shape or a triangular shape. Moreover, since the intersection part 51 inclines with respect to the tire width direction as mentioned above, the width | variety of the polyurethane foam member 8 is changing gradually along a tire axial direction according to this.

  The foamed polyurethane member 8 is fixed to the outer circumferential surface of the inner annular portion 1 or the outer circumferential surface of the intermediate annular portion 2 on the inner side in the tire radial direction, and the inner side of the inner annular portion 2 or the outer annular portion 3 on the outer side in the tire radial direction. Close to the circumference. The position where the front end of the foamed polyurethane member 8 on the outer side in the tire radial direction and the inner peripheral surface of the intermediate annular portion 2 or the inner peripheral surface of the outer annular portion 3 are closest to each other is a central portion between the adjacent connecting portions 4 and 5. It has become.

The foamed polyurethane member 8 is preferably composed of foamed polyurethane having a specific gravity of 0.4 to 0.6 g / cm ³ . When the specific gravity is smaller than 0.4 g / cm ^3, the rigidity of the polyurethane foam member 8 is insufficient, so that the connecting portions 4 and 5 are likely to buckle. On the other hand, when the specific gravity is larger than 0.6 g / cm ^3, the weight of the polyurethane foam member 8 increases, and thus the rolling resistance of the non-pneumatic tire T is likely to deteriorate.

  Moreover, it is preferable that the compression elastic modulus of the polyurethane foam which comprises the foaming polyurethane member 8 shall be 10 to 50% of the compression elastic modulus of the elastic material which comprises the support structure SS. If it is less than 10%, the rigidity of the polyurethane foam member 8 is insufficient, so that the connecting portions 4 and 5 are likely to buckle. On the other hand, if it is larger than 50%, the rigidity of the foamed polyurethane member 8 becomes too high, and the riding comfort of the non-pneumatic tire T tends to deteriorate.

  As an example of the non-pneumatic tire T, the outer diameter of the tire is 156 mm, the tire width is 57 mm, the tire cross-section height H is 33 mm, the thickness of the tread portion 6 is 10 mm, the radius of curvature R is 55 mm, and the thickness of the connecting portions 4 and 5 is An example is 2 mm and the inclination angle θ is 5 degrees.

  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.

(1) Durability Under the condition of 6 km / h, the evaluation was made based on the travel time (distance) until the tire breakage was confirmed. As shown in the schematic diagram of FIG. 6A, a load was applied to the evaluation target tire and the drum was rotated.
(2) Rolling resistance Using a rolling resistance measuring tool, the rolling resistance was evaluated based on the distance traveled by natural fall from a slope with a height of 10 cm and an inclination angle of 5 degrees. As shown in the schematic diagram of FIG. 6B, a load was applied to the tire to be evaluated, and the slope was naturally dropped.
(3) Rigidity variation test While gradually increasing the longitudinal load to be applied, the amount of displacement at that time was measured, and the state of change in stiffness was tested. The rigidity variation test was performed between the spokes (in a state of being grounded on the line A in FIG. 3) and directly under the spoke (in a state of being grounded on the line B in FIG. 3).

Example 1
A non-pneumatic tire as shown in FIG. 1 was produced and the performance was evaluated. The dimensions of the non-pneumatic tire were a tire outer diameter of 156 mm, a tire width of 57 mm, a tire cross-section height of 33 mm, a tread portion 6 thickness of 10 mm, and a tread portion 6 with a radius of curvature of 55 mm. The specific gravity of the polyurethane foam constituting the polyurethane foam member 8 was 0.5 g / cm ³ . Further, the compression elastic modulus of the polyurethane foam constituting the polyurethane foam member 8 was 20% of the compression elastic modulus of the elastic material constituting the support structure SS.

Example 2
Non-pneumatic tires as shown in FIG. 5 (a) were produced and the performance was evaluated. The non-pneumatic tire of Example 1 is the same as the non-pneumatic tire of Example 1 except that the cross-sectional shape of the polyurethane foam member 8 is a trapezoid.

Example 3
A non-pneumatic tire as shown in FIG. 5 (b) was produced and the performance was evaluated. The non-pneumatic tire of Example 1 is the same as that of Example 1 except that the cross-sectional shape of the polyurethane foam member 8 is triangular.

Example 4
A non-pneumatic tire as shown in FIG. 5 (c) was produced and the performance was evaluated. The non-pneumatic tire of Example 1 is the same as the non-pneumatic tire of Example 1 except that each gap 7 is completely filled with the foamed polyurethane member 8.

Comparative Example 1
Non-pneumatic tires as shown in FIG. 5 (d) were produced and the performance was evaluated. In this comparative example 1d, the foamed polyurethane member 8 is not provided in any of the gaps 7. The non-pneumatic tire of Example 1 is the same as the non-pneumatic tire except that the foamed polyurethane member 8 is not provided.

  FIG. 7 shows the evaluation results of durability and rolling resistance. FIG. 8 shows the result of the rigidity variation test. FIG. 8A shows the result between the spokes, and FIG. 8B shows the result immediately below the spoke. As shown in FIG. 7, Examples 1 to 4 have a longer running time until the tire breakage is confirmed and have better durability than Comparative Example 1. In the first to third embodiments, the travel distance is longer and the rolling resistance is smaller than that in the fourth embodiment. Further, as shown in FIG. 8, in any of the conditions between the spokes and immediately below the spokes, all of Examples 1 to 4 and Comparative Example 1 are almost linear in a low load region of 800 N or less. However, in the high load region of 1000 N or more between the spokes and 800 N or more immediately below the spokes, Examples 1 to 4 are almost linear as they are, but Comparative Example 1 is non-linear. This is because, in the high load region, Comparative Example 1 is buckled, while Examples 1-4 are buckled by the foamed polyurethane member.

DESCRIPTION OF SYMBOLS 1 Inner ring part 2 Middle ring part 3 Outer ring part 4 Inner connection part 5 Outer connection part 6 Tread part 7 Cavity part 8 Foam polyurethane member SS Support structure T Non-pneumatic tire

Claims (2)

In a non-pneumatic tire including a support structure that supports a load from a vehicle,
The support structure connects the inner annular portion, the outer annular portion concentrically provided outside the inner annular portion, the inner annular portion and the outer annular portion, and each is independent in the tire circumferential direction. A plurality of connecting portions,
A foamed polyurethane member is disposed in each gap portion divided by the annular portion and the connecting portion,
The foamed polyurethane member is in contact with the entire outer peripheral surface of the inner annular portion, and is close to the inner peripheral surface of the outer annular portion and a central portion between the adjacent connecting portions, and the connecting portion. Non-pneumatic tire characterized by a gap between the two . Cross-sectional shape of the foamed polyurethane member as viewed from the axial direction of the tire is according to claim 1, characterized in that the semicircular, semi-oval, trapezoidal, or triangular made narrower toward the tire radial direction outwardly Non-pneumatic tire.