JP2015113017A - Non-pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-pneumatic tire that can decrease a peak level of noise while suppressing change of rigidity in a tire circumference direction.SOLUTION: A non-pneumatic tire T comprises: an inner annular part 1; an outer annular part 2 provided concentrically outside the inner annular part 1; and a plurality of connection parts 3 that connect the inner annular part 1 to the outer annular part 2 and are provided in a tire circumference direction CD independently from each other. A plurality of coupling parts 30 between the connection parts 3 and the outer annular part 2 have at least two types of coupling-part lengths in the tire circumference direction CD; intervals between adjacent coupling parts 3 are made constant; and bending rigidity in a tire radial direction of each connection part 3 is set within 110% of the smallest bending rigidity of the plurality of connection parts 3.

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 having a solid rubber structure support a load by compressing the contact portion, but this type of tire is heavy and stiff, and does not have a shock absorbing ability like a pneumatic tire. Therefore, solid tires and cushion tires have not been adopted for passenger cars where ride comfort performance is important.

  In Patent Document 1 below, a spoke structure in which a large number of spokes are intermittently arranged in the tire circumferential direction is divided into a plurality of divided structures in the tire width direction, and the spoke structure between the adjacent divided structures is also described. Non-pneumatic tires are described in which the positions are shifted from each other in the tire circumferential direction. According to this configuration, since the distance between the spokes in the tire circumferential direction can be reduced and the difference in compression rigidity at each position in the tire circumferential direction can be reduced, vibration during running can be suppressed and riding comfort can be improved. .

  However, in the non-pneumatic tire of Patent Document 1, the distance between spokes is constant in each divided structure. In this way, when spokes of the same shape are provided at equal intervals along the tire circumferential direction, a striking sound of a constant magnitude is generated at a constant cycle during tire rolling, and noise of the order component is generated. However, noise is not generated much at frequencies other than the order component, and as a result, there is a problem that the noise becomes conspicuous.

  Therefore, Patent Document 2 below discloses a non-pneumatic tire in which the spoke circumferential arrangement is random for the purpose of reducing noise caused by the spoke circumferential arrangement. However, if the spokes having the same shape are randomly arranged while changing the distance between the spokes, the tire rigidity varies in the tire circumferential direction, and thus the steering stability performance may be lowered.

JP 2008-2222038 A JP 2012-126379 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a non-pneumatic tire that can reduce the peak level of noise while suppressing variation in rigidity in the tire circumferential direction.

The above object can be achieved by the present invention as described below.
That is, the non-pneumatic tire of the present invention 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 the tire circumferential direction. In a non-pneumatic tire comprising a plurality of connecting portions provided independently in
The connecting portions and the plurality of connecting portions of the outer annular portion have at least two types of connecting portions in the tire circumferential direction, and the interval between the adjacent connecting portions is constant,
The bending stiffness in the tire radial direction of each connecting portion is within 110% of the minimum bending stiffness among the plurality of connecting portions.

  The non-pneumatic tire of the present invention connects an inner annular portion, an outer annular portion concentrically provided outside the inner annular portion, an inner annular portion and an outer annular portion, and is independent of each other in the tire circumferential direction. And a plurality of connecting portions provided. The connecting portion between the connecting portion and the outer annular portion has at least two types of connecting portion lengths in the tire circumferential direction, and the interval between adjacent connecting portions is constant, so that a constant cycle is applied during tire rolling. No impact sound is generated by the coupling portion of the magnitude, the frequency of noise during tire rolling can be dispersed, and the peak level of noise can be reduced. On the other hand, if there are two or more types of connecting portion lengths, the rigidity in the tire circumferential direction tends to be non-uniform, and the steering stability performance tends to decrease. By setting the bending rigidity within 110% of the minimum bending rigidity, it is possible to suppress the rigidity variation in the tire circumferential direction and maintain the steering stability performance.

  In the non-pneumatic tire according to the present invention, it is preferable that the plurality of connecting portions include two or more types of connecting portions having different connecting portion widths in the tire width direction. According to this configuration, since the bending rigidity in the tire radial direction of the connecting portion can be easily adjusted and uniformed while making the length of the connecting portion in the tire circumferential direction at least two types, the rigidity variation in the tire circumferential direction is suppressed. Meanwhile, the peak level of noise can be reduced.

  In the non-pneumatic tire according to the present invention, it is preferable that a groove extending along the tire radial direction is formed on the surface of the plurality of connecting portions.

  In the non-pneumatic tire according to the present invention, it is preferable that a small hole is formed on the surface of the plurality of connecting portions.

  In the non-pneumatic tire according to the present invention, it is preferable that the plurality of connecting portions are formed of connecting portions made of different materials.

  According to these configurations, since it is possible to easily adjust and equalize the bending rigidity in the tire radial direction of the connecting portion without changing the length of the connecting portion in the tire width direction, the rigidity variation in the tire circumferential direction is suppressed. Meanwhile, the peak level of noise can be reduced.

Front view showing an example of the non-pneumatic tire of the present invention Development view of the tread surface of the non-pneumatic tire of the present invention viewed from the side The perspective view of the connection part which concerns on other embodiment. The perspective view of the connection part which concerns on other embodiment.

  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. Here, O indicates a tire shaft, and H indicates a tire cross-sectional height.

  The non-pneumatic tire T of the present invention has a support structure SS that supports a load from a 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 of the present embodiment includes an inner annular portion 1, an outer annular portion 2 provided concentrically on the outer side, and an inner annular portion. 1 and the outer annular portion 2 are connected, and a plurality of connecting portions 3 provided independently in the tire circumferential direction CD are provided.

  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 1 to 20% of the tire cross-section height H and more preferably 2 to 10% from the viewpoint of reducing weight and improving durability while sufficiently transmitting force to the connecting portion 3. preferable.

  The inner diameter of the inner annular portion 1 is appropriately determined in accordance with the rim on which the non-pneumatic tire T is mounted and the dimensions of the axle. 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 connecting portion 3. 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. However, the inner ring portion 1, the outer ring portion 2, and the connection portion 3 are used from the viewpoint of enabling integral molding when the support structure SS is manufactured. Are preferably basically 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 outer annular portion 2, and the connecting portion 3 are preferably reinforced by 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 outer annular portion 2 is preferably a cylindrical shape with a constant thickness from the viewpoint of improving uniformity. The thickness of the outer annular portion 2 is preferably 1 to 20% of the tire cross-section height H, and preferably 2 to 10% from the viewpoint of reducing weight and improving durability while sufficiently transmitting the force from the connecting portion 3. More preferred.

  The inner diameter of the outer annular portion 2 is appropriately determined according to its use. 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 2 in the tire width direction is appropriately determined depending on 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 2 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 2 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 weight and improving durability while sufficiently transmitting the force from the connecting portion 3.

  When the tensile modulus of the outer annular portion 2 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 2 with the reinforcing fiber, adhesion between the outer annular portion 2 and the belt layer becomes sufficient.

  The connecting portion 3 connects the inner annular portion 1 and the outer annular portion 2, and a plurality of connecting portions 3 are provided so as to be independent from each other in the tire circumferential direction CD with an appropriate interval therebetween.

  FIG. 2 is a development view of the tread surface when the non-pneumatic tire T of FIG. 1 is viewed from the outside in the tire radial direction. When the non-pneumatic tire T is viewed from the outer side in the tire radial direction, the connecting portion 3 is not actually seen by the outer annular portion 2 or the like, but in FIG. 2, the connecting portion 3 is indicated by a solid line. If the part which the connection part 3 and the outer side annular part 2 couple | bond is the coupling | bond part 30, the some coupling | bond part 30 has the coupling | bond part length of at least 2 types of tire circumferential direction CD. In the present embodiment, the plurality of coupling portions 30 have three types of coupling portion lengths a, b, and c. A coupling portion having a coupling portion length of a is defined as a coupling portion 3S, and the coupling portion length is b. A certain connecting portion is referred to as a connecting portion 3M, and a connecting portion having a coupling portion length c is referred to as a connecting portion 3L. In the present embodiment, the coupling portion length b is longer than the coupling portion length a, and the coupling portion length c is longer than the coupling portion length b. At this time, the coupling portion length b and the coupling portion length c are preferably within 300% of the coupling portion length a.

  The plurality of connecting portions 3 are configured by arranging three types of connecting portions 3S, 3M, and 3L along the tire circumferential direction CD. For example, the connecting portions 3S, 3M, 3L are arranged as 3S, 3M, 3L, 3S, 3S, 3L,. Moreover, in the example shown in FIG. 1, it is arranged like 3S, 3M, 3L, 3S, 3M, 3L,. However, the arrangement of the connecting portions 3S, 3M, 3L is not limited to these, and can be set as appropriate.

  The interval between adjacent coupling portions 30 is constant. In the present embodiment, the interval L1 between the connecting portion 3S and the connecting portion 3M, the interval L2 between the connecting portion 3M and the connecting portion 3L, and the interval L3 between the connecting portion 3L and the connecting portion 3S are equal. Similarly, the intervals between all adjacent coupling portions 30 are equal.

  The number of connecting portions 3 of the entire tire is preferably 10 to 120, and preferably 40 to 100 from the viewpoint of reducing weight, improving power transmission, and improving durability while sufficiently supporting the load from the vehicle. More preferred.

  Examples of the shape of each connecting portion 3 include a plate-like body and a columnar body, and the cross-sectional shape of the connecting portion 3 is rectangular. These connecting portions 3 extend in the radial direction or in a direction inclined from the radial direction in the front sectional view. In the present invention, in the front sectional view, the extending direction of the connecting portion 3 is preferably within ± 25 ° in the radial direction, more preferably within ± 15 ° in the radial direction, and most preferably in the radial direction.

  The thickness of the connecting portion 3 in the tire circumferential direction is 1 to 30% 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 inner annular portion 1 and the outer annular portion 2. Is preferable, and 1 to 20% is more preferable.

  The bending stiffness in the tire radial direction of each connecting portion 3 is within 110% of the minimum bending stiffness among the plurality of connecting portions 3. Preferably, the bending rigidity of each connecting portion 3 is the same.

In the present embodiment, it is assumed that the connecting portion 3S has the minimum bending rigidity A among the three types of connecting portions. At this time, for example, if the cross-sectional secondary moment of the connecting portion 3S is I _S and the cross-sectional secondary moment of the connecting portion 3M is I _M , the bending rigidity B of the connecting portion 3M is A × (I _M / I _S ). . The shapes and materials of the connecting part 3S and the connecting part 3M are set so that the bending rigidity B of the connecting part 3M is within 110% of the bending rigidity A of the connecting part 3S. Similarly, the shapes and materials of the connecting part 3S and the connecting part 3L are set so that the bending rigidity C of the connecting part 3L is within 110% of the bending rigidity A of the connecting part 3S. In the present embodiment, as shown in FIG. 2, the bending rigidity of the connecting portions 3S, 3M, and 3L is adjusted by changing the connecting portion width in the tire width direction WD.

  The width of the connecting portion 3 in the tire width direction is appropriately determined depending on 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 connecting portion 3 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. .

  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 2 is provided outside the outer annular portion 2 of the support structure SS. Moreover, in this embodiment, as shown in FIG. 1, the example in which the tread rubber 7 is provided in the further outer side of the reinforcement layer 6 is shown. As the reinforcing layer 6 and the tread rubber 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]
(1) In the above-described embodiment, in order to adjust the bending rigidity of the connecting portion 3 in the tire radial direction, the connecting portion width in the tire width direction of the connecting portion 3 is varied, but as shown in FIG. A groove 4 extending along the tire radial direction may be appropriately formed on the surface of the portion 3.

  Moreover, in order to adjust the bending rigidity in the tire radial direction of the connection part 3, you may form the small hole 5 in the surface of the connection part 3, as shown in FIG.

  Moreover, in order to adjust the bending rigidity in the tire radial direction of the connection part 3, you may vary the material which comprises the connection part 3. FIG.

  (2) In the above-described embodiment, the plurality of connecting portions 3 are configured by three types of connecting portions, but may be configured by four or more types of connecting portions. However, from the viewpoint of simplifying the structure and facilitating the production while exhibiting the effects of the present invention, it is preferable to use 3 to 5 types of connecting portions.

  (3) As another embodiment of the present invention, the inner annular portion 1, the intermediate annular portion provided concentrically outside the inner annular portion 1, and the outer annular portion provided concentrically. The outer annular part 2, the inner annular part 1 and the intermediate annular part are connected, and a plurality of inner connecting parts provided independently in the tire circumferential direction CD, and the outer annular part 2 and the intermediate annular part are connected. In the non-pneumatic tire including a plurality of outer coupling portions provided independently in the tire circumferential direction CD, the plurality of coupling portions of the outer coupling portion and the outer annular portion 2 are at least two kinds of tire circumferential directions. The coupling portion has a length and the interval between adjacent coupling portions is constant, and the bending stiffness in the tire radial direction of each outer coupling portion is 110% of the minimum bending stiffness among the plurality of outer coupling portions. It may be within. In other words, in the present invention, for the plurality of outer connecting portions connected to the outer annular portion 2, the connecting portion length and the bending rigidity may be set as in the present invention. Etc. are not particularly limited.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below.

Noise measurement The sound pressure was measured when two passengers traveled on a noise measurement course at a speed of 60 km / h. The peak level of Comparative Example 1 was used as a reference.

Steering stability performance Four panelists evaluated the starting, turning and braking on the test course in a comprehensive manner. The result was evaluated by an index when Comparative Example 1 was set to 100. The larger the value, the better the steering stability performance.

Comparative Example 1
A support structure including an inner ring (corresponding to the inner annular portion), an outer ring (corresponding to the outer annular portion), and a spoke (corresponding to the connecting portion), provided on the outer periphery, with the dimensions and physical properties shown in Table 1. A non-pneumatic tire including three reinforcing layers and tread rubber was produced, and the above performance was evaluated. There was only one type of spoke. The evaluation results are also shown in Table 1.

Example 1
A support structure including an inner ring (corresponding to the inner annular portion), an outer ring (corresponding to the outer annular portion), and a spoke (corresponding to the connecting portion), provided on the outer periphery, with the dimensions and physical properties shown in Table 1. A non-pneumatic tire including three reinforcing layers and tread rubber was produced, and the above performance was evaluated. The spokes were made into three types of plate shapes in which the thickness in the tire circumferential direction and the width in the tire width direction were different from each other. The evaluation results are also shown in Table 1.

Example 2
A support structure including an inner ring (corresponding to the inner annular portion), an outer ring (corresponding to the outer annular portion), and a spoke (corresponding to the connecting portion), provided on the outer periphery, with the dimensions and physical properties shown in Table 1. A non-pneumatic tire including three reinforcing layers and tread rubber was produced, and the above performance was evaluated. The spokes were made into three types of plate shapes with different thicknesses in the tire circumferential direction. The plate width in the tire width direction was the same, but the flexural rigidity was adjusted by forming a groove extending along the tire radial direction as shown in FIG. 3 on the surface of the spoke. The evaluation results are also shown in Table 1.

Example 3
A support structure including an inner ring (corresponding to the inner annular portion), an outer ring (corresponding to the outer annular portion), and a spoke (corresponding to the connecting portion), provided on the outer periphery, with the dimensions and physical properties shown in Table 1. A non-pneumatic tire including three reinforcing layers and tread rubber was produced, and the above performance was evaluated. The spokes were made into three types of plate shapes with different thicknesses in the tire circumferential direction. The plate width in the tire width direction was the same, but the bending rigidity was adjusted by forming a small hole as shown in FIG. 4 on the surface of the spoke. The evaluation results are also shown in Table 1.

  From the results in Table 1, the following can be understood. Compared with Comparative Example 1, the non-pneumatic tires of Examples 1 to 3 were able to reduce the peak level of noise, and were able to maintain the steering stability performance by suppressing the rigidity variation in the tire circumferential direction.

DESCRIPTION OF SYMBOLS 1 Inner ring part 2 Outer ring part 3 Connection part 4 Groove 5 Small hole 30 Connection part SS Support structure T Non-pneumatic tire

Claims (5)

An inner annular portion, an outer annular portion concentrically provided on the outer side of the inner annular portion, the inner annular portion and the outer annular portion are connected, and a plurality of independently provided in the tire circumferential direction. In a non-pneumatic tire comprising a connecting portion,
The connecting portions and the plurality of connecting portions of the outer annular portion have at least two types of connecting portions in the tire circumferential direction, and the interval between the adjacent connecting portions is constant,
The non-pneumatic tire characterized by the bending rigidity in the tire radial direction of each connecting part being within 110% of the minimum bending rigidity among the plurality of connecting parts.   2. The non-pneumatic tire according to claim 1, wherein the plurality of connecting portions are composed of two or more types of connecting portions having different connecting portion widths in the tire width direction.   The non-pneumatic tire according to claim 1 or 2, wherein a groove extending along a tire radial direction is formed on a surface of the plurality of connecting portions.   The non-pneumatic tire according to any one of claims 1 to 3, wherein a small hole is formed on a surface of the plurality of connecting portions.   The non-pneumatic tire according to any one of claims 1 to 4, wherein the plurality of connecting portions are configured by connecting portions made of different materials.

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