JP6597738B2 - Non-pneumatic tire - Google Patents

Description

  The present invention relates to a non-pneumatic tire having excellent durability performance.

  A ring tread portion that contacts the road surface, an annular inner peripheral portion located inside the tread portion in the radial direction of the tire, and a plurality of connecting portions that radially extend from the tread portion and the inner peripheral portion. Pneumatic tires are known. The connecting portion is generally formed of rubber or resin. In such a non-pneumatic tire, when the connecting portion repeats compression and tensile deformation during running, a large hysteresis loss occurs at the connecting portion. The hysteresis loss becomes heat energy and causes the connecting portion to generate heat. This heat generation deteriorates the connecting portion and deteriorates the durability performance of the non-pneumatic tire.

JP 2008-13951 A International Publication No. 2003/018332

  The present invention has been devised in view of the above circumstances, and its main object is to provide a non-pneumatic tire having excellent durability performance.

  The present invention includes an annular tread portion that contacts a road surface, an annular inner circumferential portion that is located on the inner side in the tire radial direction of the tread portion, and a plurality of connecting portions that connect the tread portion and the inner circumferential portion. A non-pneumatic tire including at least one connecting portion made of a first material made of resin or rubber, and a resin or rubber having a higher thermal conductivity than the first material. And a covering portion made of a second material and covering at least a part of the main body and exposed to the outside.

  In the non-pneumatic tire according to the present invention, it is preferable that the thermal conductivity of the second material is twice or more the thermal conductivity of the first material.

  In the non-pneumatic tire according to the present invention, the second material preferably has a thermal conductivity of 1.9 W / (m · k) or more.

  In the non-pneumatic tire according to the present invention, it is preferable that a thickness of the covering portion is 0.001 to 2 mm.

  In the non-pneumatic tire according to the present invention, the first material is preferably a urethane resin, and the second material is preferably made of a silicone-based, urethane-based, or acrylic-based resin or rubber.

  In the non-pneumatic tire according to the present invention, it is preferable that a rough surface portion having a surface roughness of 1 to 30 μm is formed on at least a part of the connecting portion.

  In the non-pneumatic tire according to the present invention, the rough surface portion is preferably formed on the covering portion.

  The present invention includes an annular tread portion that contacts a road surface, an annular inner circumferential portion that is located on the inner side in the tire radial direction of the tread portion, and a plurality of connecting portions that connect the tread portion and the inner circumferential portion. This is a non-pneumatic tire including At least one of the connecting parts is made of a first material made of resin or rubber, and a second material made of resin or rubber having a higher thermal conductivity than the first material, and at least a part of the main body part. And a covering portion exposed to the outside. Thereby, the heat of the main body generated by the hysteresis loss is smoothly released to the outside through the covering portion. Therefore, the non-pneumatic tire of the present invention has excellent durability performance because the deterioration of the connecting portion due to heat generation is suppressed.

1 is a perspective view of a non-pneumatic tire showing an embodiment of the present invention. It is a perspective view which shows the state which mounted | wore the wheel with the non-pneumatic tire of FIG. It is the elements on larger scale which cut | disconnected the non-pneumatic tire of FIG. 1 in the circumferential direction.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the non-pneumatic tire (hereinafter sometimes simply referred to as “tire”) 1 of the present embodiment is used for, for example, a passenger car or a heavy-duty vehicle. The non-pneumatic tire 1 can support a load by the physical rigidity of the tire. Therefore, it is different from a pneumatic tire in which pressurized air is filled inside the tire.

  As shown in FIG. 1, the tire 1 includes a tread portion 2, an inner peripheral portion 3, and a plurality of connecting portions 4 that connect between them.

  The tread portion 2 is an annular body that is continuous in the tire circumferential direction. The tread portion 2 has a constant width W, for example. The tread portion 2 includes, for example, a hard rubber portion 2A and a resin portion 2B disposed on the inner side of the rubber portion 2A in the tire radial direction. The rubber portion 2A of the tread portion 2 includes a tread surface 2a that contacts the road surface on the outer surface in the tire radial direction. The rubber portion 2A is provided with a reinforcing cord layer (not shown) in which, for example, metal or organic fiber cords are arranged.

  The inner peripheral portion 3 is located inside the tread portion 2 in the tire radial direction. The inner peripheral portion 3 is an annular body that is continuous in the tire circumferential direction. The inner peripheral part 3 has a certain width in the tire width direction, for example. The inner peripheral portion 3 is made of, for example, a resin material. The inner peripheral portion 3 and the tread portion 2 are both arranged concentrically.

  For example, a wheel H as shown in FIG. 2 is fixed to the inner peripheral portion 3 of the tire 1 of the present embodiment, not a rim used for a pneumatic tire. This wheel H is attached to an axle (not shown).

  As FIG. 1 shows, the connection part 4 of this embodiment comprises the plate shape extended in a tire axial direction, and is distribute | arranged to the tire circumferential direction. The outer end 4 a of the connecting portion 4 in the tire radial direction is fixed to the tread portion 2, and the inner end 4 b of the connecting portion 4 in the tire radial direction is fixed to the inner peripheral portion 3. The connection part 4 of this embodiment is inclined with respect to the tire radial direction, for example. The connecting portions 4 and 4 that are adjacent to each other in the tire circumferential direction are inclined in opposite directions with respect to the tire radial direction. When a vertical load is applied to the axle, the load depends on the tensile rigidity of the connecting portion 4 disposed above the axle and the compressive rigidity of the connecting portion 4 disposed below the axle. Supported.

  For example, the outer end 4a and the inner end 4b of the connecting portion 4 extend along the tire axial direction. For example, the connecting portion 4 has a width Wa equal to that of the inner peripheral portion 3. The shape of the connecting portion 4 is not limited to such an embodiment. For example, there are various types such as a zigzag extending in the tire radial direction or the circumferential direction, and a net-like extending in the circumferential section of the tire. Aspect is employed.

  FIG. 3 shows a partially enlarged cross-sectional view of the tire 1 cut in the tire circumferential direction. As shown in FIG. 3, the connecting portion 4 includes a main body portion 8 and a covering portion 9.

  The main body portion 8 constitutes a main portion of the connecting portion 4, and extends from the tread portion 2 to the inner peripheral portion 3, for example.

  The main body 8 is formed of a first material made of resin or rubber. When the first material is rubber, it is desirable to have a durometer A hardness of, for example, 70 to 95 degrees in an environment of a temperature of 23 ° C. in accordance with JISK6253. In the case where the first material is a resin, for example, a urethane resin having a hardness capable of sufficiently exerting a load supporting ability is desirable. Such a main body 8 absorbs vibration during traveling and improves riding comfort performance.

  The covering portion 9 is exposed to the outside so as to cover at least a part of the main body portion 8, in this embodiment, both surfaces 8 a and 8 a of the main body portion 8 facing the tire circumferential direction. That is, the main body portion 8 is not exposed to the outside in the tire circumferential direction, and the covering portion 9 is in contact with the atmosphere. In addition, the coating | coated part 9 may cover all the surfaces of the main-body part 8, and may be exposed outside.

  The covering portion 9 is formed of a second material that is a resin or rubber having a higher thermal conductivity than the first material. Thereby, when the tire 1 travels, the heat of the main body portion 8 generated by the hysteresis loss due to the compression and tensile deformation of the connecting portion 4 is smoothly released to the atmosphere via the covering portion 9. Therefore, the non-pneumatic tire 1 of the present embodiment has excellent durability performance because the deterioration of the connecting portion 4 due to heat generation is suppressed.

  The thermal conductivity of the second material is preferably at least twice that of the first material, more preferably at least four times, and even more preferably at least seven times. That is, when the thermal conductivity of the second material is more than twice the thermal conductivity of the first material, the heat of the main body portion 8 is smoothly conducted to the covering portion 9 and the heat generation of the connecting portion 4 is more effectively released. can do. In order to exhibit the above-described action more effectively, the thermal conductivity of the second material is preferably 1.0 W / (m · k) or more, more preferably 1.9 W / (m · k). That's it. As such a second material, for example, a silicone-based, urethane-based, or acrylic-based resin or rubber is desirably the base.

  The thickness t of the covering portion 9 is preferably 0.001 to 2 mm. That is, when the thickness t of the covering portion 9 is less than 0.001 mm, the heat of the main body portion 8 may not be smoothly conducted to the covering portion 9. When the thickness t of the covering portion 9 exceeds 2 mm, the thickness T of the main body portion 8 becomes small, the strength of the connecting portion 4 is lowered, and the durability of the tire 1 may be deteriorated. From such a viewpoint, the thickness t of the covering portion 9 is more preferably 0.01 mm or more, and more preferably 1.0 mm or less.

  As shown in FIG. 1, the connecting portion 4 of the present embodiment is provided with a rough surface portion 10 whose surface is roughened. Since the rough surface portion 10 increases the surface area of the connecting portion 4, the heat of the main body portion 8 is released more smoothly into the atmosphere. For rough surface processing, for example, embossing, embossing or pear processing is desirable.

  The surface roughness Ra of the rough surface portion 10 is preferably 1 to 30 μm. When the surface roughness Ra of the rough surface portion 10 is less than 1 μm, the effect of sufficiently increasing the surface area of the connecting portion 4 is small. When the surface roughness Ra of the rough surface portion 10 exceeds 30 μm, stress due to compression and tensile deformation during traveling concentrates on the connecting portion 4 and the like, and the durability performance of the tire 1 may be deteriorated. For this reason, the surface roughness Ra of the rough surface portion 10 is more preferably 2 μm or more, and more preferably 20 μm or less. In the present specification, “surface roughness” is defined in Japanese Industrial Standard JIS B0601: 2001 “Product Geometric Specification (GPS) —Surface Properties: Contour Curve Method—Terminology, Definitions, and Surface Property Parameters” It is represented by the arithmetic mean height of the contour curve (arithmetic mean roughness of the roughness curve).

  In the present embodiment, the rough surface portion 10 is formed in the covering portion 9 (shown in FIG. 3). Thereby, the above-mentioned operation is more effectively exhibited.

  Although the non-pneumatic tire of the present invention has been described in detail above, the present invention is not limited to the specific embodiment described above, and can be implemented with various modifications.

A non-pneumatic tire having the basic structure shown in FIG. 1 was prototyped based on the specifications shown in Table 1, and the heat generation properties of each sample tire were tested. The common specifications are as follows.
Tread width W: 195mm
Tire outer diameter Ha: 635 mm
Tire radial height Hb of connecting part: 90mm
Link width Wa: 185mm
Body thickness T (shown in FIG. 3): 3 mm
Material of main body: Thermosetting polyurethane (Thermal conductivity: 0.25 W / (m · k))
Covering part (second material) material: silicone rubber base (thermal conductivity: 1.9 W / (m · k))
Covering part (second material) material: urethane resin base (thermal conductivity: 0.8 W / (m · k))
Covering part (second material) material: epoxy resin base (thermal conductivity: 1.0 W / (m · k))
Tread rubber material: Natural rubber + Styrene / butadiene rubber Tread resin material: Thermoset polyurethane Inner circumference material: Thermoset polyurethane

As a heat generation test, each test tire was run under the following conditions using a drum testing machine. Thereafter, the maximum temperature of the connecting portion was measured by a thermal imager (surface thermometer). The results are displayed as an index with the value of Comparative Example 1 being 100. The smaller the value, the better.
Mileage: 10km
Load: 4.55kN
Speed: 60km / h
The test results are shown in Table 1.

  As a result of the test, it was confirmed that the temperature of the connecting portion of the tire of the example was lower than that of the tire of the comparative example. For this reason, the durability performance of the example tire is improved as compared with the tire of the comparative example. In addition, the same test was performed by changing the tire size or the shape of the connecting portion, but the same result was obtained.

2 Tread part 3 Inner part 4 Connecting part 8 Body part 9 Covering part

Claims (7)

Non-air including an annular tread portion that comes in contact with the road surface, an annular inner peripheral portion that is located on the inner side in the tire radial direction of the tread portion, and a plurality of connecting portions that connect the tread portion and the inner peripheral portion. Tire,
At least one of the connecting parts is
A main body formed of a first material made of resin or rubber;
A coating portion made of a second material that is a resin or rubber having a higher thermal conductivity than the first material and covering at least a part of the main body portion and exposed to the outside,
The connecting portion is arranged in the tire circumferential direction,
The connecting portions adjacent to each other in the tire circumferential direction are inclined in opposite directions with respect to the tire radial direction ,
A non-pneumatic tire characterized in that a rough surface portion having a surface roughness of 1 to 30 μm is formed on at least a part of the connecting portion .   The non-pneumatic tire according to claim 1, wherein the thermal conductivity of the second material is at least twice that of the first material.   The non-pneumatic tire according to claim 1 or 2, wherein the second material has a thermal conductivity of 1.9 W / (m · k) or more.   The non-pneumatic tire according to any one of claims 1 to 3, wherein the covering portion has a thickness of 0.001 to 2 mm.   The non-pneumatic tire according to any one of claims 1 to 4, wherein the first material is a urethane resin, and the second material is made of a silicone-based, urethane-based, or acrylic-based resin or rubber.   The non-pneumatic tire according to any one of claims 1 to 5, wherein the covering portion is in contact with the atmosphere. The non-pneumatic tire according to any one of claims 1 to 6, wherein the rough surface portion is formed in the covering portion .

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