JP2012006560A - Non-pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-pneumatic tire that has raised durability by relaxing stress concentration and inhibiting generation of buckling of a spoke center part.SOLUTION: In a non-pneumatic tire T with a support structure SS which supports a load from a vehicle, the support structure SS includes: an inside annular part 1; an outer annular part 3 prepared outside of the inside annular part 1 in the shape of a concentric circle; and a plurality of connection parts 45 which connect the inside annular parts 1 and the outer annular part 3. The connection parts 45 has neck parts 45d and 45e smaller than a center part 45a in cross section respectively between a center part 45a and both ends 45b and 45c in tire radial direction.

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 structure member.

  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. Patent Document 2 also describes a non-pneumatic tire in which a spoke structure in which an annular outer peripheral member and an inner peripheral member are connected by a large number of spokes is joined to the inner peripheral side of the tread ring. The non-pneumatic tires of Patent Documents 1 and 2 are free from air leakage unlike a pneumatic tire, and do not have a weight problem like a solid tire.

JP 2007-118913 A JP 2007-238019 A

  In a non-pneumatic tire as described in Patent Documents 1 and 2, when a high load is applied, normally, buckling occurs at the center portion of the spoke, stress concentration occurs at that portion, causing failure. . References 1 and 2 describe non-pneumatic tires with a narrow spoke center, but when the spoke width is narrowed, stress concentration and buckling are more likely to occur, resulting in durability. Sex will get worse.

  Accordingly, an object of the present invention is to provide a non-pneumatic tire with improved durability by relaxing stress concentration at the center of a spoke and suppressing the occurrence of buckling.

  In order to solve the above problem, a non-pneumatic tire according to the present invention is a non-pneumatic tire including a support structure that supports a load from a vehicle. The support structure includes an inner annular portion and an outer side of the inner annular portion. An outer annular portion provided concentrically, and a plurality of coupling portions that couple the inner annular portion and the outer annular portion, the coupling portion between a central portion and both end portions in a tire radial direction. Each has a constricted portion having a smaller cross-sectional area than the central portion.

  The effect of the non-pneumatic tire by this structure is demonstrated. The non-pneumatic tire of the present invention includes a support structure that supports a load from a vehicle. The support structure includes an inner annular portion, an outer annular portion provided outside the inner annular portion, and an inner annular portion. And a plurality of connecting portions that connect the outer annular portion. Normally, buckling is likely to occur at the central portion in the tire radial direction of the connecting portion, but according to the above configuration, a constricted portion having a smaller cross-sectional area than the central portion is provided at a place other than the central portion. As the part is buckled from the constricted part, the stress concentration in the central part is dispersed and buckling in the central part can be suppressed. As a result, according to the present invention, it is possible to provide a non-pneumatic tire with improved durability by alleviating stress concentration at the spoke center and suppressing the occurrence of buckling.

  In the non-pneumatic tire according to the present invention, the connecting portion is a plate-like body extending in the tire radial direction and the tire width direction, and the width dimension of the constricted portion in the tire width direction is larger than that of the central portion. It is preferable that it is small.

  By making the width dimension of the constricted portion in the tire width direction smaller than the central portion, the cross-sectional area of the constricted portion can be easily made smaller than the central portion. Also, in order to make the width dimension of the constricted part in the tire width direction smaller than the center part, it is possible to dent the end part of the connecting part in the tire width direction, so a convex part is provided on the inner surface of the mold, etc. It can be manufactured with only a simple improvement. In addition, the tire radial direction and the tire width direction in the present invention include not only a case where the tire radial direction and the tire width direction completely coincide with each other but also a direction inclined with respect to the tire radial direction and the tire width direction.

  In the non-pneumatic tire according to the present invention, the connecting portion is a plate-like body extending in the tire radial direction and the tire width direction, and the thickness of the constricted portion in the tire circumferential direction is thinner than the central portion. It is preferable that

  By making the thickness of the constricted portion in the tire circumferential direction thinner than the central portion, the cross-sectional area of the constricted portion can be easily made smaller than the central portion.

  In the non-pneumatic tire according to the present invention, the central portion is rounded outward, the constricted portion is rounded inward, and the central portion and the constricted portion are formed continuously. Preferably it is.

  According to this configuration, since the central portion and the constricted portion are rounded, the stress is less likely to be concentrated than in the case of a straight line.

  In order to solve the above problems, a non-pneumatic tire according to the present invention is a non-pneumatic tire provided with a support structure that supports a load from a vehicle. The support structure includes an inner annular portion and an inner annular portion. An intermediate annular portion provided concentrically on the outer side, an outer annular portion provided concentrically on the outer side of the intermediate annular portion, and a plurality of inner connecting portions that connect the inner annular portion and the intermediate annular portion. A plurality of outer connecting portions that connect the outer annular portion and the intermediate annular portion, and the inner connecting portion and the outer connecting portion are disposed between the center portion and both end portions in the tire radial direction, Each has a constricted portion having a smaller cross-sectional area.

  The operational effects of the non-pneumatic tire with this configuration are as described above. According to the present invention, the stress concentration at the center portion of the spoke is alleviated and the occurrence of buckling is suppressed, thereby improving the durability. Non-pneumatic tires can be provided.

Front view showing an example of the non-pneumatic tire of the present invention 1 is a cross-sectional view taken along arrows I-I in FIG. Sectional drawing which shows another embodiment of a non-pneumatic tire Partial enlarged view showing another embodiment of a non-pneumatic tire Front view showing another embodiment of a non-pneumatic tire II sectional view of FIG. Specifications for Comparative Examples 1 and 2 Shape of connecting portion of Comparative Example 3 Shape of connecting portion of embodiment 6 Evaluation results in examples

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the configuration of the non-pneumatic tire T of the present invention will be described. FIG. 1 is a front view showing an example of a non-pneumatic tire T. FIG. FIG. 2 is a cross-sectional view taken along the line II in FIG. Here, O indicates the axial center, and H1 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 of the present invention only needs to be provided with such a support structure SS. A reinforcing layer, a member for fitting with an axle or a rim, and the like may be provided.

  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 portion 3, a plurality of inner link portions 4 that connect the inner ring portion 1 and the intermediate ring portion 2, and a plurality of outer links that connect the outer ring portion 3 and the intermediate ring portion 2. Part 5. However, 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 side are provided as described later. The connecting portion 5 may be continuous to form one connecting portion 45.

  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 2 to 7%, and 3 to 6% of the tire cross-section height H1 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 that is appropriately determined in accordance with the dimensions of the rim on which the non-pneumatic tire T is mounted, the axle, and the like. It can be made much smaller. However, when an alternative to a general pneumatic tire is assumed, 250 to 500 mm is preferable, and 330 to 440 mm is more preferable.

  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 when an alternative to a general pneumatic tire is assumed, it is preferably 100 to 300 mm, more preferably 130 to 250 mm. preferable.

  The tensile modulus of the inner annular portion 1 is preferably 5 to 180000 MPa, more preferably 7 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 5 to 100 MPa, more preferably 7 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 foam material, The thing which foamed said thermoplastic elastomer, crosslinked rubber, and other resin 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 shape of the intermediate annular portion 2 is preferably a cylindrical shape with a constant thickness from the viewpoint of improving uniformity. However, the shape of the intermediate annular portion 2 is not limited to a cylindrical shape, and may be a polygonal cylindrical shape.

  The thickness of the intermediate annular portion 2 is preferably 3 to 10% of the tire cross-section height H1 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. When the length obtained by subtracting the inner diameter of the inner annular portion 1 from the inner diameter of the outer annular portion 3 is d1, and the length obtained by subtracting the inner diameter of the inner annular portion 1 from the inner diameter of the intermediate annular portion 2 is d2, d1 and d2 are It is preferable to set the inner diameter of the intermediate annular portion 2 so as to satisfy the relationship of (1/3) × d1 ≦ d2 ≦ (2/3) × d1.

  The axial width of the intermediate annular portion 2 is appropriately determined according to the application and the like, but is preferably 100 to 300 mm, more preferably 130 to 250 mm, assuming an alternative to a general pneumatic tire.

  The tensile modulus of the intermediate annular portion 2 is preferably 8000 to 18000 MPa, more preferably 10,000 to 50000 MPa from the viewpoint of sufficiently reinforcing the inner connecting portion 4 and the outer connecting portion 5 to improve durability and load capacity. preferable.

  Since the tensile modulus of the intermediate annular portion 2 is preferably higher than that of the inner annular portion 1, a fiber reinforced material in which a thermoplastic elastomer, a crosslinked rubber, or other resin is reinforced with fibers or the like is preferable.

  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 7% of the tire cross-section height H1, and preferably 2 to 5% from the viewpoint of reducing the weight and improving the durability while sufficiently transmitting the force from the outer connecting portion 5. 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 than before. However, when an alternative to a general pneumatic tire is assumed, 420 to 750 mm is preferable, and 480 to 680 mm is more preferable.

  The axial width of the outer annular portion 3 is appropriately determined according to the application and the like, but is preferably 100 to 300 mm, and more preferably 130 to 250 mm when an alternative to a general pneumatic tire is assumed.

  The tensile modulus of the outer annular portion 3 can be set to the same level as that of the inner annular portion 1 when the reinforcing layer 6 is provided on the outer periphery of the outer annular portion 3 as shown in FIG. In the case where such a reinforcing layer 6 is not provided, 5 to 180000 MPa is preferable, and 7 to 50000 MPa is more preferable 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, adhesion between the outer annular portion 3 and the belt layer 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 parts 4 are preferably provided with a certain interval 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, 10 to 80 are preferable, and 40 to 60 are more preferable. FIG. 1 shows an example in which 40 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 extending in the tire radial direction and the tire width direction 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 ± 25 ° in the tire radial direction in the front sectional view. The tire radial direction is more preferably within ± 15 °, and the tire radial direction is most preferable. In FIG. 1, the example which has arrange | positioned the inner side connection part 4 along a tire radial direction is shown.

  The thickness of the inner connecting portion 4 in the tire circumferential direction is such that the tire cross-sectional height is increased from the viewpoint of reducing weight, improving durability, and improving lateral rigidity while sufficiently transmitting the force from the inner annular portion 1 and the intermediate annular portion 2. 2 to 12% of length H1 is preferable, and 3 to 10% is more preferable. In this embodiment, although the thickness of the inner side connection part 4 is made constant, you may change along a tire radial direction so that it may mention later.

  The inner connecting portion 4 has constricted portions 4d and 4e each having a smaller cross-sectional area than the central portion 4a between the central portion 4a in the tire radial direction and both end portions 4b and 4c. In the present embodiment, the thickness in the tire circumferential direction (direction perpendicular to the paper surface in FIG. 2) is substantially constant, and the widths L2 and L3 of the constricted portions 4d and 4e in the tire width direction are larger than the width L1 of the central portion 4a. Is also narrower. The relationship among the width L1, the width L2, and the width L3 is preferably L1> L2> 0.5 × L1 and L1> L3> 0.5 × L1. In the present embodiment, L2 and L3 are substantially the same.

  Further, it is preferable that the central portion 4a, both end portions 4b and 4c, and the constricted portions 4d and 4e are formed so as to be rounded (R). The central portion 4a is rounded outwardly R1, the constricted portions 4d and 4e are rounded inwardly R2 and R3, and the end portions 4b and 4c are rounded outwardly R4 and R5. Is attached. The sizes of the roundnesses R1 to R5 are not particularly limited, but it is preferable to appropriately set the roundnesses R1 to R5 so that the roundnesses R1 to R5 are smoothly continuous with each other in consideration of the relationship between the widths L1 to L3. Further, the roundness R1 to R5 is preferably 5 to 500 mm.

  The tensile modulus of the inner connecting portion 4 is preferably 5 to 50 MPa, more preferably 7 to 20 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 portions 5 are preferably provided at regular intervals from the viewpoint of improving uniformity.

  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 a viewpoint of aiming at improvement, 30-150 are preferable and 40-120 are more preferable. Moreover, it is preferable that the number of the outer connection parts 5 is a multiple of the number of the inner connection parts 4. FIG. 1 shows an example in which 80 outer connecting portions 5 are provided that are twice the inner connecting portions 4. That is, the number of the outer connecting portions 5 is larger than the number of the inner connecting portions 4, and as a result, the interval between the adjacent outer connecting portions 5 is narrower than the interval between the adjacent inner connecting portions 4. Yes.

  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 extending in the tire radial direction and the tire width direction is shown. In the present invention, the outer connecting portion 5 is inclined with respect to the tire radial direction in a front sectional view from the viewpoint of causing the intermediate annular portion 2 to bear the deflection of the outer connecting portion 5 and uniformizing the deformation of the support structure SS. It is preferable. However, the outer connecting portion 5 is not necessarily inclined with respect to the tire radial direction, and may be disposed in the same direction as the tire radial direction.

  The angle θ of the outer connecting portion 5 that is inclined with respect to the tire radial direction is preferably 30 ° or less. If the angle θ is too large, the non-pneumatic tire T cannot obtain sufficient rigidity, and tension is hardly transmitted between the inner connecting portion 4 and the outer connecting portion 5.

  Moreover, it is more preferable that the angle θ of the outer connecting portion 5 inclined with respect to the tire radial direction is 5 ° or more. If the angle θ is too small, the deflection of the outer connecting portion 5 cannot be effectively borne by the intermediate annular portion 2, and the pressure fluctuation in the ground contact surface also increases due to the improved compression rigidity of the outer connecting portion 5. End up.

  In this embodiment, as shown in FIG. 1, the two outer connecting portions 5 are inclined by an angle θ in a direction symmetrical to the tire radial direction, and are combined with the one inner connecting portion 4 along the tire radial direction. The example arrange | positioned in a Y shape seeing from a tire axial direction is shown.

  The thickness of the outer connecting portion 5 in the tire circumferential direction is such that the tire cross-sectional height is increased from the viewpoint of reducing weight, improving durability, and improving lateral rigidity while sufficiently transmitting the force from the outer annular portion 3 and the intermediate annular portion 2. 1 to 10% of length H1 is preferable, and 2 to 8% is more preferable. Furthermore, in the non-pneumatic tire T of the present invention, it is preferable that the thickness of the outer connecting portion 5 is thinner than the thickness of the inner connecting portion 4. By making the thickness of the outer connecting portion 5 smaller than the thickness of the inner connecting portion 4, the compression rigidity can be lowered, and the fluctuation in the circumferential direction of the tire rigidity can be satisfactorily suppressed. In the present embodiment, the thickness of the outer connecting portion 5 is constant, but may be changed along the tire radial direction as will be described later.

  As shown in FIG. 2, the outer connecting portion 5 has a constricted portion having a smaller cross-sectional area than the central portion between the central portion and both end portions in the tire radial direction. Since the shape of the outer connecting portion 5 is substantially the same as the shape of the inner connecting portion 4, a detailed description thereof is omitted here.

  The tensile modulus of the outer connecting portion 5 is preferably 5 to 50 MPa, more preferably 7 to 20 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, as shown in FIG. 1, an example is shown in which a reinforcing layer 6 that reinforces bending deformation of the outer annular portion 3 is provided outside the outer annular portion 3 of the support structure SS. Moreover, in this embodiment, as shown in FIG. 1, the example in which the tread layer 7 is provided in the further outer side of the reinforcement layer 6 is shown. As the reinforcing layer 6 and the tread layer 7, it is possible to provide the same layers as those of a conventional pneumatic tire belt layer. Moreover, it is possible to provide the same pattern as a conventional pneumatic tire as a tread pattern.

[Other Embodiments]
In the above embodiment, both end portions 4b and 4c in the tire radial direction of the inner connecting portion 4 are rounded R4 and R5 toward the outer side. However, as shown in FIG. Good. The same applies to the outer connecting portion 5.

  In said embodiment, the inner side connection part 4 makes the cross-sectional area of the constriction parts 4d and 4e smaller than the center part 4a by making the width dimension of the tire width direction of the constriction parts 4d and 4e smaller than the center part 4a. is doing. However, the width of the inner connecting portion 4 in the tire width direction remains constant, and the thickness of the constricted portions 4d and 4e in the tire circumferential direction is made thinner than the central portion 4a, so that the cross-sectional areas of the constricted portions 4d and 4e are reduced to the center. You may make it smaller than the part 4a. FIG. 4 shows a partially enlarged view seen from the front of the tire. In this embodiment, the width dimension in the tire width direction (the direction perpendicular to the paper surface in FIG. 4) is substantially constant, and the thicknesses D2in and D3in of the constricted portions 4d and 4e in the tire circumferential direction are the thickness D1in of the central portion 4a. It is thinner than. The relationship among the thickness D1in, the thickness D2in, and the thickness D3in is preferably D1in> D2in> 0.5 × D1in and D1in> D3in> 0.5 × D1in. In the present embodiment, D2in and D3in are substantially the same. The same applies to D1out, D2out, and D3out of the outer connecting portion 5. D1out to D3out are dimensions in a direction perpendicular to the virtual center line of the outer connecting portion 5.

  In the above embodiment, the support structure SS includes the intermediate annular portion 2, but the intermediate annular portion 2 is not necessarily required. As shown in the front view of FIG. 5 and the cross-sectional view of FIG. 2 may be provided, and the inner connecting part 4 and the outer connecting part 5 may be continuous to form one connecting part 45. The connecting portion 45 is also configured to have constricted portions 45d and 45e having a smaller cross-sectional area than the central portion 45a between the central portion 45a and both end portions 45b and 45c in the tire radial direction.

  In said embodiment, although the inner side connection part 4 is left-right symmetrical with respect to the tire width direction, it does not necessarily need to be left-right symmetrical. In the case of a non-pneumatic tire used for a vehicle that is cornered with a camber, the left and right sides may be asymmetrical on the in and out sides. Specifically, the values of roundness R1 to R5 may be different on the left and right.

  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. The measurement results are shown in FIG.

(1) Longitudinal rigidity The tire longitudinal rigidity when a non-pneumatic tire was loaded with 2.45 kN and 4.9 kN was measured. Examples 1-4 are shown by an index when the comparative example 1 is set to 100, and the larger this value, the better. Comparative Example 3 and Examples 5 and 6 are shown as indices when Comparative Example 2 is set to 100, and the larger this value, the better.

(2) Maximum principal stress The outer spoke when the non-pneumatic tire is loaded with 2.45 kN, that is, the outer connecting portion 5 when the intermediate annular portion 2 is present, or the connecting portion 45 when the intermediate annular portion 2 is absent. The maximum principal stress was measured. The higher the maximum principal stress, the worse the durability. Examples 1-4 are shown by an index when the comparative example 1 is set to 100, and the smaller this value, the better. Comparative Example 3 and Examples 5 and 6 are indicated by an index when Comparative Example 2 is 100, and the smaller this value, the better.

(3) Stress distribution The outer spoke when a non-pneumatic tire is loaded with 2.45 kN, that is, the outer connecting portion 5 when the intermediate annular portion 2 is present, or the inside of the connecting portion 45 when the intermediate annular portion 2 is absent. The standard deviation of stress at The greater the standard deviation, the more uniformly the stress is applied. Examples 1-4 are shown by an index when the comparative example 1 is set to 100, and the larger this value, the better. Comparative Example 3 and Examples 5 and 6 are shown as indices when Comparative Example 2 is set to 100, and the larger this value, the better.

Comparative Example 1
7, the inner ring (corresponding to the inner annular portion 1), the intermediate ring (corresponding to the intermediate annular portion 2), the outer ring (corresponding to the outer annular portion 3), the inner spoke (inner connecting portion). 4), a support structure including outer spokes (corresponding to the outer connecting portion 5), a three-layer reinforcing layer provided on the outer periphery thereof, and a non-pneumatic tire including a tread rubber were manufactured, and the above performance was evaluated. . In Comparative Example 1, the inner connecting portion 4 and the outer connecting portion 5 were arranged in a Y shape as shown in FIG. The inner connecting part 4 and the outer connecting part 5 were rectangular plate-like bodies, and no constricted part was provided. For forming the support structure, a mold having a space corresponding to the support structure is used, and a raw material liquid of an elastic material (polyurethane resin) (isocyanate-terminated prepolymer: Sofranate manufactured by Toyo Tire & Rubber Co., Ltd.) Curing agent: MOCA manufactured by Ihara Chemical Co.) was filled using a urethane casting machine and solidified.

Example 1
The inner connecting part 4 and the outer connecting part 5 of Comparative Example 1 were shaped as shown in FIG. R1 = R2 = R3 = R4 = R5 = 10 mm, L1 = 140 mm, and L2 = L3 = 120 mm.

Example 2
The inner connecting part 4 and the outer connecting part 5 of Comparative Example 1 were shaped as shown in FIG. R1 = R2 = R3 = 15 mm, L1 = 140 mm, and L2 = L3 = 120 mm.

Example 3
The inner connecting part 4 and the outer connecting part 5 of Comparative Example 1 were shaped as shown in FIG. D1in = 6 mm, D2in = D3in = 5 mm, D1out = 4 mm, and D2out = D3out = 3 mm.

Example 4
The inner connecting part 4 and the outer connecting part 5 of Example 1 were asymmetrical with respect to the tire width direction. That is, in the inner connecting part 4 and the outer connecting part 5 shown in FIG. 2, the value of R1 to R5 on one side in the tire width direction is 1.5 times (15 mm) the value of R1 to R5 (10 mm) on the other side. did. L1 = 140 mm and L2 = L3 = 123 mm.

Comparative Example 2
A supporting structure including an inner ring (corresponding to the inner annular portion 1), an outer ring (corresponding to the outer annular portion 3), and outer spokes (corresponding to the connecting portion 45), and the outer periphery thereof, in the dimensions and physical properties shown in FIG. A non-pneumatic tire provided with three reinforcing layers and a tread rubber was prepared, and the performance was evaluated. In the comparative example 2, the connection part 45 was arrange | positioned as shown in FIG. The connection part 45 was a rectangular plate-shaped body and was not provided with a constricted part. For forming the support structure, a mold having a space corresponding to the support structure is used, and a raw material liquid of an elastic material (polyurethane resin) (isocyanate-terminated prepolymer: Sofranate manufactured by Toyo Tire & Rubber Co., Ltd.) Curing agent: MOCA manufactured by Ihara Chemical Co.) was filled using a urethane casting machine and solidified.

Comparative Example 3
The connection part 45 of the comparative example 2 was made into the shape as shown in FIG. R6 = 60 mm, L4 = 140 mm, and L5 = 120 mm.

Example 5
The connection part 45 of the comparative example 2 was made into the shape as shown in FIG. R1 = R2 = R3 = R4 = R5 = 20 mm, L1 = 140 mm, and L2 = L3 = 120 mm.

Example 6
The connection part 45 of the comparative example 2 was made into the shape as shown in FIG. D1 = 6 mm and D2 = D3 = 4.5 mm.

  The following can be understood from the results of FIG. Compared with Comparative Example 1, the non-pneumatic tires of Examples 1 to 4 have a slightly lower longitudinal rigidity in a low load region of 2.45 kN, for example, but have a higher longitudinal rigidity in a high load region of 4.9 kN, for example. Therefore, there is no reduction in rigidity due to buckling. Similarly, the non-pneumatic tires of Examples 5 and 6 are also higher in longitudinal rigidity in a high load region of, for example, 4.9 kN than that of Comparative Example 2.

  Compared with Comparative Example 1, the non-pneumatic tires of Examples 1 to 4 are superior in maximum principal stress and stress dispersion. Similarly, the non-pneumatic tires of Examples 5 and 6 are superior in the maximum principal stress and the stress dispersion value as compared with Comparative Example 2.

  Further, in Comparative Example 3 in which the cross-sectional area of the central portion in the tire radial direction is the smallest, the values of longitudinal rigidity, maximum principal stress, and stress dispersion are all inferior to Comparative Example 2.

DESCRIPTION OF SYMBOLS 1 Inner ring part 2 Middle ring part 3 Outer ring part 4 Inner connection part 4a Central part 4b, 4c Both ends 4d, 4e Neck part 5 Outer connection part 45 Connection part 45b, 45c Both end part 45d, 45e Neck part SS Support structure T Non-pneumatic tire

Claims (5)

In a non-pneumatic tire including a support structure that supports a load from a vehicle,
The support structure 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,
The non-pneumatic tire is characterized in that the connecting portion has a constricted portion having a smaller cross-sectional area than the central portion between a central portion and both end portions in the tire radial direction. The connecting portion is a plate-like body extending in the tire radial direction and the tire width direction,
2. The non-pneumatic tire according to claim 1, wherein a width dimension of the constricted portion in a tire width direction is smaller than that of the central portion. The connecting portion is a plate-like body extending in the tire radial direction and the tire width direction,
2. The non-pneumatic tire according to claim 1, wherein a thickness of the constricted portion in a tire circumferential direction is thinner than the central portion.   3. The center portion is rounded outward, the constricted portion is rounded inward, and the central portion and the constricted portion are formed continuously. Or the non-pneumatic tire of 3. In a non-pneumatic tire including a support structure that supports a load from a vehicle,
The support structure includes an inner annular portion, an intermediate annular portion provided concentrically outside the inner annular portion, an outer annular portion provided concentrically outside the intermediate annular portion, and the inner annular portion. A plurality of inner connecting portions that connect the portion and the intermediate annular portion, and a plurality of outer connecting portions that connect the outer annular portion and the intermediate annular portion,
The non-pneumatic tire, wherein the inner connecting portion and the outer connecting portion each have a constricted portion having a smaller cross-sectional area than the central portion between a central portion and both end portions in a tire radial direction.

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