JP2013079037A - Non-pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-pneumatic tire the ride comfort of which is upgraded while improving durability.SOLUTION: In the non-pneumatic tire T provided with a support structure body SS supporting a load from a vehicle, the support structure body SS has an inner annular part 1, a middle annular part 2 provided to be concentrically circular in the outside of the inner annular part 1, an outer annular part 3 provided to be concentrically circular in the outside of the middle annular part 2, a plurality of inner connection parts 4 that connect the inner annular part 1 and the middle annular part 2, and a plurality of outer connection parts 5 that connect the outer annular part 3 and the middle annular part 2. At least either of the inner connection parts 4 and the outer connection parts 5 includes a connection part body 51 extending radially along a tire, and two branch parts 52 branching from one end of the connection part body 51 and extending to the middle annular part 2.

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 improving the durability, the outer peripheral ring and the inner peripheral ring arranged concentrically are connected by a web, and further connected to the side surface of the web. In addition, a plurality of ribs extending laterally connected to the outer peripheral ring and the inner peripheral ring are provided at intervals in the circumferential direction, and the ribs are inclined with respect to the radial surface. There has been proposed a non-pneumatic tire in which an intermediate wheel that crosses the web and the rib is concentrically interposed between the inner ring and the inner ring. In this non-pneumatic tire, the plurality of ribs arranged on the inner side of the intermediate wheel and the plurality of ribs arranged on the outer side of the intermediate wheel are coupled to the intermediate wheel while being shifted from each other. The rigidity of the part is improved and the durability is improved. However, although the durability can be improved by improving the rigidity of the buffer portion, the riding comfort is deteriorated.

  Patent Document 2 below discloses an inner layer ring, an intermediate layer ring, an outer layer ring, an inner layer arch-shaped rib between the inner layer ring and the intermediate layer ring, and an outer layer between the intermediate layer ring and the outer layer ring. There is described a non-pneumatic tire which is a continuous arch-shaped annular corrugated elastic body by repeating a ridge and a valley. In this non-pneumatic tire, riding comfort is improved by a buffering effect by bending and restoring the arch-shaped rib. However, at the joint portion between the inner layer and outer layer arched ribs and the intermediate layer, the stress tends to increase and the durability tends to deteriorate.

JP-A-1-311902 International Publication No. 2007/057975

  Thus, it has been difficult for conventional non-pneumatic tires to achieve both durability and riding comfort. Accordingly, an object of the present invention is to provide a non-pneumatic tire with improved riding comfort while improving durability.

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. An intermediate annular portion, an outer annular portion concentrically provided on the outer side of the intermediate annular portion, a plurality of inner connecting portions that connect the inner annular portion and the intermediate annular portion, the outer annular portion, and the A plurality of outer connecting portions that connect the intermediate annular portion, and at least one of the inner connecting portion and the outer connecting portion includes a connecting portion main body extending along a tire radial direction, and one end of the connecting portion main body. And two branch portions extending from the portion to the intermediate annular portion.

  In the non-pneumatic tire of the present invention, at least one of the inner connecting portion and the outer connecting portion includes a connecting portion main body and two branch portions branched from one end of the connecting portion main body. Branch portions extend to the intermediate annular portion. According to this configuration, since the number of coupling portions between the inner coupling portion and / or the outer coupling portion and the intermediate annular portion is increased, stress generated in each coupling portion can be reduced, and durability can be improved. In addition, the inner connecting part and / or the outer connecting part are joined to the intermediate annular part by two branched branches, so that the inner connecting part and / or the outer connecting part are not connected to each other. Since the deformation concentrated on the portion and / or the outer connecting portion can be borne by the intermediate annular portion in a wider range, the deformation of the support structure can be made uniform and the riding comfort can be improved.

  In the non-pneumatic tire according to the present invention, an inner coupling point where the inner coupling portion is coupled to the intermediate annular portion and an outer coupling point where the outer coupling portion is coupled to the intermediate annular portion are spaced apart in the tire circumferential direction. Is preferably provided. According to this configuration, since the intermediate annular portion bears the deformation of the inner connecting portion and the outer connecting portion at different positions, the riding comfort can be further improved.

  In the non-pneumatic tire according to the present invention, it is preferable that an angle between the two branch portions is 60 to 140 degrees. If the angle between the two branches is within this range, the ride comfort can be effectively improved while sufficiently improving the durability. If this angle is 140 degrees or less, when the connecting portion main body is pushed toward the intermediate annular portion by grounding, the two branch portions are deformed to prevent the connecting portion main body from colliding with the intermediate annular portion. be able to.

  In the non-pneumatic tire according to the present invention, it is preferable that a reinforcing portion formed so as to fill the corner portion is provided at a corner portion formed by the two branch portions. According to this structure, since the rigidity of the branch point of an inner side connection part and an outer side connection part can be improved, rotation deformation of the inner side connection part and outer side connection part centering on a branch point can be suppressed. Thereby, it is possible to prevent the inner connecting portion and the outer connecting portion from buckling and greatly deforming during driving and braking, and the durability and riding comfort are not deteriorated.

Front view showing an example of the non-pneumatic tire of the present invention The figure which expanded a part of non-pneumatic tire of Drawing 1 The figure which expanded a part of non-pneumatic tire concerning another embodiment The figure which expanded a part of non-pneumatic tire concerning another embodiment The figure which expanded a part of non-pneumatic tire concerning another embodiment The figure which expanded a part of non-pneumatic tire concerning another embodiment The figure which expanded a part of non-pneumatic tire of comparative example 1 The figure which expanded a part of non-pneumatic tire of comparative example 2 The figure which expanded a part of non-pneumatic tire of comparative example 3

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the configuration of the non-pneumatic tire of the present invention will be described. FIG. 1 shows an example of a non-pneumatic tire, and FIG. 2 is an enlarged view of a part of the non-pneumatic tire of 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, and a member corresponding to a tread on the outer side (outer peripheral side) or inner side (inner peripheral side) of the 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.

  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 width in the tire width direction of the inner annular portion 1 is appropriately determined according to the use, the length of the axle, and the like. However, when an alternative to a general pneumatic tire is assumed, 100 to 300 mm is preferable, and 130 to 250 mm is preferable. More preferred.

  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 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. .

  Reinforcing fibers include reinforcing fibers such as long fibers, short fibers, woven fabrics, and non-woven fabrics, but as a form using long fibers, fibers arranged in the tire width 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 width in the tire width direction of the intermediate annular portion 2 is appropriately determined according to the use 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 width of the outer annular portion 3 in the tire width direction is appropriately determined according to the use 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 connecting portions 4 provided over the entire circumference (when a plurality of inner connecting portions 4 are provided in the tire width 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 property, 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 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 4 with a tire cross-section height H1 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. -12% is preferable and 6-10% is more preferable.

  The tensile modulus of the inner connecting portion 4 is preferably 5 to 50 MPa from the viewpoint of reducing the weight, improving the durability, and improving the lateral rigidity while sufficiently transmitting the force from the inner annular portion 1 and the intermediate annular portion 2. 7-20 MPa is more 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.

  The outer connecting portion 5 includes a connecting portion main body 51 that extends along the tire radial direction, and two branch portions 52 that branch from one end of the connecting portion main body 51 and extend to the intermediate annular portion 2. .

  The connecting portion main body 51 extends linearly from the outer annular portion 3 toward the intermediate annular portion 2. The connecting portion main body 51 is coupled to the outer annular portion 3 at an end portion 51a on the outer side in the tire radial direction, and is branched into two branch portions 52 at an end portion 51b on the inner side in the tire radial direction.

  The two branch parts 52 are symmetrical with respect to the extending direction of the connecting part main body 51, that is, the tire radial direction. Thereby, the outer side connection part 5 is carrying out the substantially Y shape by the front view as a whole. The branch portion 52 extends linearly from the end portion 51b of the connecting portion main body 51 toward the intermediate annular portion 2, and is coupled to the intermediate annular portion 2 at the outer coupling point 5a. Here, the outer coupling point 5a passes through the center of the branch portion 52 (however, when the outer coupling portion 5 described later is coupled to the intermediate annular portion 2 without branching, it passes through the center of the outer coupling portion 5). Line) and a line passing through the center of the intermediate annular portion 2 intersect.

  An inner coupling point 4a at which the inner coupling portion 4 is coupled to the intermediate annular portion 2 and an outer coupling point 5a at which the outer coupling portion 5 is coupled to the intermediate annular portion 2 are provided at a distance D1 in the tire circumferential direction. . Here, the inner coupling point 4a is a line passing through the center of the inner coupling portion 4 (however, when the inner coupling portion 4 described later is coupled to the intermediate annular portion 2 by two branch portions, the center of the branch portion is defined. And a line passing through the center of the intermediate annular portion 2 intersects. The distance D1 is a distance along the intermediate annular portion 2. The distance D1 is preferably 10 mm or more. Moreover, it is preferable that the distance D1 between the two outer coupling points 5a where the two branch portions 52 of the outer coupling portion 5 are coupled to the intermediate annular portion 2 and the inner coupling point 4a are the same.

  The angle θ sandwiched between the two branch parts 52 is preferably 60 to 140 degrees, and more preferably 80 to 120 degrees. When the angle θ is smaller than 60 degrees, the rigidity of the outer connecting portion 5 is increased, leading to deterioration in riding comfort. When the angle θ is larger than 140 degrees, when the connecting portion main body 51 is pushed toward the intermediate annular portion 2 by grounding, the two branch portions 52 are deformed and the connecting portion main body 51 collides with the intermediate annular portion 2. There is a fear. Further, when the angle θ is larger than 140 degrees, the two branch portions 52 greatly expand in the tire circumferential direction, so that it is necessary to reduce the number of outer connecting portions 5 provided in the tire circumferential direction, which leads to deterioration in riding comfort. .

  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 connection part main body 51 and the inner connection part 4 of the outer connection part 5 do not necessarily have to be provided in the same direction as 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 tire width 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 property, 10 to 80 are preferable, and 40 to 60 are more preferable. FIG. 1 shows an example in which 40 outer connecting portions 5 are provided in the same manner as the inner connecting portions 4.

  The shapes of the connection part main body 51 and the branch part 52 are plate-shaped bodies, respectively. The thickness of the connecting portion main body 51 and the branch portion 52 is such that the tire cross-section height is increased from the viewpoint of reducing weight, improving durability, and improving lateral rigidity while sufficiently transmitting the force from the intermediate annular portion 2 and the outer annular portion 3. 4 to 12% of length H1 is preferable, and 6 to 10% is more preferable. Moreover, the thickness of the branch part 52 is smaller than the thickness of the connection part main body 51, and 30 to 90% of the thickness of the connection part main body 51 is preferable. If the thickness of the branch portion 52 is smaller than 30% of the thickness of the connecting portion main body 51, the branch portion 52 may be buckled. Further, if the thickness of the branch portion 52 is larger than 90% of the thickness of the connecting portion main body 51, the rigidity of the two branch portions 52 becomes too large, and the ride comfort may be deteriorated.

  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.

  It is preferable that a corner portion 54 formed by the two branch portions 52 is provided with a reinforcing portion 55 formed so as to fill the corner portion 54. By providing the reinforcement part 55, the volume of the branch point of the outer connection part 5 can be increased, and the rigidity of the branch point can be increased. The surface of the reinforcing portion 55 is a straight line along the tire circumferential direction when viewed from the front. The distance D2 in the tire radial direction from the intersection 5b of the two branch parts 52 to the surface of the reinforcing part 55 is preferably 5 to 12 mm, and more preferably 6 to 10 mm. When the distance D2 is shorter than 5 mm, the volume at the branch point cannot be increased sufficiently, and the reinforcing effect of the reinforcing portion 55 is not exhibited. Further, as shown in FIG. 3, the surface of the reinforcing portion 55 may be a circular arc that is concave when viewed from the front. Thereby, since the reinforcement part 55 and the branch part 52 continue smoothly, stress is hard to concentrate compared with the case of a straight line. In this case, the distance D2 in the tire radial direction from the intersection 5b of the two branch parts 52 to the surface of the reinforcing part 55 is preferably 5 to 12 mm, and more preferably 6 to 10 mm. When the distance D2 is shorter than 5 mm, the volume at the branch point cannot be increased sufficiently, and the reinforcing effect of the reinforcing portion 55 is not exhibited.

  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.

<Another embodiment>
(1) In the above-described embodiment, the outer connecting portion 5 includes the connecting portion main body 51 and the two branch portions 52. However, as illustrated in FIG. 4A, the inner connecting portion 4 has the tire radial direction. A connecting portion main body 41 extending along the two ends, and two branch portions 42 branched from one end of the connecting portion main body 41 and extending to the intermediate annular portion 2 may be provided.

  (2) Further, as shown in FIG. 4B, the inner connecting portion 4 and the outer connecting portion 5 may each include a connecting portion main body and two branch portions.

  (3) Further, as shown in FIG. 4C, the outer connecting portion 5 includes a connecting portion main body 51 extending along the tire radial direction and one end 51 b of the connecting portion main body 51 to the intermediate annular portion 2. You may make it provide the two branch parts 52 extended, and the two branch parts 53 branched from the other edge part 51a of the connection part main body 51, and extended to the outer side annular part 3. FIG. However, the Y-shaped outer connecting portion 5 as shown in FIG. 2 is particularly preferable for improving weight reduction and durability as compared with the case where two sets of branch portions 52 and 53 as shown in FIG. 4C are provided.

  (4) In addition to reinforcing the branch point of the outer connecting portion 5 with the reinforcing portion 55, the inner connecting point 4a where the inner connecting portion 4 is connected to the intermediate annular portion 2, and the outer side where the outer connecting portion 5 is connected to the intermediate annular portion 2. It is preferable to reinforce the connection point 5a with a reinforcing portion. Moreover, when the inner side connection part 4 has branched, it is preferable to reinforce the branch point of the inner side connection part 4 with a reinforcement part. In any case, rotational deformation of the inner connecting part 4 or the outer connecting part 5 around the branch point or the coupling point can be suppressed, and durability can be improved.

  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) Riding comfort performance The amount of deflection of the tire shaft was measured while rotating the non-pneumatic tire in a state where a longitudinal load of 250 kgf was applied to the tire shaft (axial core O in FIG. 1). When the amplitude of the deflection amount, that is, the difference between the maximum value and the minimum value is small, the change in the longitudinal rigidity accompanying the rotation of the tire is small, and the riding comfort is good.

(2) Durability Performance When a longitudinal load of 250 kgf was applied, the maximum stress at the inner coupling point or the outer coupling point was determined. It shows with an index when Example 1 is set to 100. The smaller this value, the less the stress concentration at the bonding point and the better the durability.

Example 1
A non-pneumatic tire having a support structure having the shape shown in FIG. However, the branch point of the outer connecting part and the outer connecting point where the outer connecting part is connected to the intermediate annular part are not reinforced by the reinforcing part. Table 1 shows the results of ride performance and durability performance.

Example 2
In the non-pneumatic tire of Example 1, Example 2 was obtained by reinforcing the branch point of the outer connecting part and the outer connecting point where the outer connecting part is connected to the intermediate annular part. Table 1 shows the results of ride performance and durability performance.

Example 3
A non-pneumatic tire having a support structure having the shape shown in FIG. Table 1 shows the results of ride performance and durability performance.

Comparative Example 1
A non-pneumatic tire having a support structure having the shape shown in FIG. Table 1 shows the results of ride performance and durability performance.

Comparative Example 2
A non-pneumatic tire having a support structure having the shape shown in FIG. Table 1 shows the results of ride performance and durability performance.

Comparative Example 3
A non-pneumatic tire having a support structure having the shape shown in FIG. Table 1 shows the results of ride performance and durability performance.

  From the results in Table 1, the following can be understood. Compared with the non-pneumatic tire of Comparative Example 3, the non-pneumatic tire of Example 1 has a longitudinal rigidity that accompanies the rotation of the tire by branching the outer connecting portion and joining the intermediate annular portion with two branches. The change is small and the stress at the coupling point is also small. In Comparative Example 1, the inner connecting portion and the outer connecting portion are shifted in the tire circumferential direction, and the deformation concentrated on the inner connecting portion and the outer connecting portion is caused to be borne on the intermediate annular portion. The change in longitudinal rigidity is smaller than However, as in the first embodiment, the outer connecting portion is branched and joined to the intermediate annular portion by two branches, so that the intermediate annular portion can be loaded in a wider range than the comparative example 1, and the longitudinal rigidity change Can be reduced. Further, since the number of coupling points in Example 1 is larger than that in Comparative Example 1, the stress at each coupling point is also small.

  In Example 2, the stress at the connection point is smaller than that in Example 1 due to the reinforcement of the connection point and the reinforcement of the branch point. However, since the rigidity of the outer connecting portion is increased, the longitudinal rigidity change is slightly increased.

  In Comparative Example 2, the number of the outer coupling portions is larger than that of the inner coupling portions, and the inner coupling point and the outer coupling point are provided at intervals in the tire circumferential direction, but the longitudinal rigidity change is large. . This is because the outer coupling point and the inner coupling point are close to each other and the impact absorbing performance of the intermediate annular portion cannot be fully utilized. In Comparative Example 3, since the inner coupling point and the outer coupling point are at the same position, the longitudinal rigidity change is large, and the stress at the coupling point is also very large.

DESCRIPTION OF SYMBOLS 1 Inner ring part 2 Middle ring part 3 Outer ring part 4 Inner connection part 4a Inner connection point 5 Outer connection part 5a Outer connection point 41 Connection part main body 42 Branch part 51 Connection part main body 51a End part 51b End part 52 Branch part 53 Branch Part 54 Corner 55 Reinforcing part

Claims (4)

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,
At least one of the inner connecting portion and the outer connecting portion includes a connecting portion main body extending along the tire radial direction, and two branch portions extending from one end of the connecting portion main body and extending to the intermediate annular portion. And a non-pneumatic tire.   The inner coupling point at which the inner coupling portion is coupled to the intermediate annular portion and the outer coupling point at which the outer coupling portion is coupled to the intermediate annular portion are provided at intervals in the tire circumferential direction. The non-pneumatic tire according to claim 1.   The non-pneumatic tire according to claim 1 or 2, wherein an angle between the two branches is 60 to 140 degrees. 4. The non-restriction according to claim 1, wherein a reinforcing portion formed so as to fill the corner portion is provided at a corner portion formed by the two branch portions. 5. Pneumatic tire.