Cushion tire

Abstract

To provide a cushion tire which inhibits increase of a tire temperature.SOLUTION: The invention relates to a cushion tire 2 whose surface includes a first side surface 14a, a second side surface 14b, and an inner peripheral surface 16 and which is attached to a rim R. The cushion tire 2 has one or more heat exhaust grooves 22 on the surface. Each of the heat exhaust grooves 22 has: (1) a side part 26 which is recessed from the first side surface 14a or the second side surface 14b and in which its outer end is located at the outer side relative to an outer end of a flange F of the rim R in a radial direction; and (2) an inner periphery part 24 which is recessed from the inner peripheral surface 16 and continuous with the side part 26.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cushion tire. More specifically, the present invention relates to a cushion tire for industrial vehicles such as forklifts.

Background Art

[0002] Cushion tires (also referred to as solid tires or non-pneumatic tires) are used in industrial vehicles such as forklifts. Such tires are often used under high loads. When the vehicle is in use, the tire may be greatly deformed, and the heat generation of the tire may increase. The increase in the tire temperature due to this heat generation affects the durability of the tire. Furthermore, the increase in this tire temperature can be a factor in radial run-out (RRO). Consideration of a cushion tire with suppressed tire temperature rise is disclosed in Japanese Patent Application Laid-Open No. 2007-15493.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a demand for a cushion tire with further suppressed tire temperature rise.

[0005] An object of the present invention is to provide a cushion tire with suppressed tire temperature rise.

Means for Solving the Problems

[0006] The present invention relates to a cushion tire whose surface has a first side surface, a second side surface, and an inner peripheral surface and is mounted on a rim. The cushion tire has one or two or more exhaust grooves on the surface. Each exhaust groove (1) A side portion that is recessed from the first side surface or the second side surface, and whose outer end in the radial direction is located outside the outer end of the flange of the rim. and (2) An inner peripheral portion that is recessed from the inner peripheral surface and is continuous with the side portion. It has.

[0007] Preferably, the exhaust heat groove has a first side portion recessed from the first side surface and a second side portion recessed from the second side surface, and the inner peripheral portion is continuous with the first side portion and continuous with the second side portion.

[0008] Preferably, a plurality of the exhaust heat grooves are arranged at intervals in the circumferential direction.

[0009] A cushion tire according to another preferred embodiment (1) A first exhaust heat groove having a first side portion recessed from the first side surface, the inner peripheral portion being continuous with the first side portion, and the inner peripheral portion not reaching the equatorial plane. and (2) A second exhaust heat groove having a second side portion recessed from the second side surface, the inner peripheral portion being continuous with the second side portion, and the inner peripheral portion not reaching the equatorial plane. It has.

[0010] Preferably, in the axial direction, the ratio (L1 / W) of the distance L1 from the equatorial plane to the inner end of the first exhaust heat groove to the half-width W of the inner peripheral surface is 25% or more, and the ratio (L2 / W) of the distance L2 from the equatorial plane to the inner end of the second exhaust heat groove to the half-width W is 25% or more.

[0011] This cushion tire includes a base that contacts the rim and a tread located radially outside the base. Preferably, the base includes a first outer portion that extends in the circumferential direction and whose inner side surface position in the axial direction is substantially the same as the position of the inner end of the first exhaust groove, a second outer portion that extends in the circumferential direction and whose inner side surface position in the axial direction is substantially the same as the position of the inner end of the second exhaust groove, and a central portion that extends in the circumferential direction and is located between the first outer portion and the second outer portion. The radial thickness of the first outer portion and the radial thickness of the second outer portion are both larger than the radial thickness of the central portion.

[0012] Preferably, the thickness of the first outer portion is 1.2 times or more and 1.4 times or less the thickness of the central portion, and the thickness of the second outer portion is 1.2 times or more and 1.4 times or less the thickness of the central portion.

[0013] Preferably, a plurality of the first exhaust grooves are arranged at intervals in the circumferential direction, and a plurality of the second exhaust grooves are arranged at intervals in the circumferential direction.

[0014] Preferably, longitudinal grooves extending in the circumferential direction are provided on the inner peripheral surface, and the longitudinal grooves are connected to at least one exhaust groove.

[0015] Preferably, the longitudinal grooves are not located on the equatorial plane, and in the axial direction, the ratio (Lv / W) of the distance Lv from the equatorial plane to the inner end of the longitudinal grooves to the half-width W of the inner peripheral surface is 25% or more.

[0016] Preferably, this cushion tire further includes a base that contacts the rim, a tread located radially outside the base, and a bead embedded in the base and extending in the circumferential direction. The bead and the longitudinal grooves overlap in the radial direction.

[0017] The assembly according to the present invention includes a rim having a flange, and a cushion tire mounted on the rim and having a surface with a first side surface, a second side surface, and an inner circumferential surface. The cushion tire has one or more exhaust heat grooves on the surface. Each exhaust heat groove has (1) a side portion that is recessed from the first side surface or the second side surface and whose outer end in the radial direction is located outside the outer end of the flange of the rim and (2) an inner circumferential portion that is recessed from the inner circumferential surface and is continuous with the side portion and has.

Effect of the Invention

[0018] The cushion tire according to the present invention includes an exhaust heat groove having an inner circumferential portion recessed from the inner circumferential surface and a side portion recessed from the side surface. In the radial direction, the outer end of the side portion is located outside the outer end of the flange of the rim. The outer end of this exhaust heat groove is not blocked by the rim. This exhaust heat groove effectively discharges the heat generated at the contact portion between the cushion tire and the rim to the outside. In this tire, the temperature rise due to heat generation is suppressed.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

[0020] Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings as appropriate.

[0021] [First Embodiment] FIG. 1 is a cross-sectional view showing a cushion tire 2 according to an embodiment of the present invention. In FIG. 1, the vertical direction is the radial direction of the tire 2, the horizontal direction is the axial direction of the tire 2, and the direction perpendicular to the paper surface is the circumferential direction of the tire 2. In FIG. 1, the dashed-dotted line CL represents the equatorial plane of the tire 2.

[0022] In FIG. 1, what is indicated by the reference numeral R is a rim. This rim R is a standard rim. A standard rim means a rim defined in the standard on which the tire 2 depends. The "Standard Rim" in the JATMA standard, the "Design Rim" in the TRA standard, and the "Measuring Rim" in the ETRTO standard are standard rims. What is indicated by the reference numeral F is the flange of this rim R.

[0023] In FIG. 1, this tire 2 is mounted on the rim R. The set of the rim R and the cushion tire 2 mounted on this rim R constitutes an assembly 4. In FIG. 1, the double arrow RW indicates the rim width. A set of solid lines S is a virtual straight line that defines the rim width RW. The rim width RW is represented by the axial distance between these solid lines S. In FIG. 1, the double arrow W represents the half-width of the inner peripheral surface of the cushion tire 2. In this specification, the half-width W is defined as half of the rim width RW.

[0024] As shown in FIG. 1, this tire 2 includes a tread 6 and a base 8. Among the surfaces of this tire 2, the radially outer surface is referred to as a tread surface 10. The radially inner surface is referred to as an inner peripheral surface 16. The axially outer surface is referred to as a side surface 14. On the side surface 14, there are a first side surface 14a and a second side surface 14b. In other words, the surface of this tire 2 includes a tread surface 10, an inner peripheral surface 16, a first side surface 14a, and a second side surface 14b.

[0025] The tread 6 has a shape that is convex radially outward. The tread 6 forms a tread surface 10 that contacts the road surface. Grooves 12 are engraved on the tread surface 10. A tread pattern is formed by these grooves 12. The side surface of the tread 6 forms a part of the side surface 14 of this tire 2. The tread 6 is made of crosslinked rubber that is excellent in wear resistance and grip. In this embodiment, the tread 6 is formed of a single rubber. This tread 6 may be formed of two or more rubbers.

[0026] The base 8 is located radially inside the tread 6. The base 8 is made of cross-linked rubber. The inner peripheral surface of the base 8 is in contact with the bottom surface 20 of the rim R. The inner peripheral surface of the base 8 forms the inner peripheral surface 16 of this tire 2. The radially inner part of the side surface of the base 8 is in contact with the flange F of the rim R. The side surface of the base 8 forms a part of the side surface 14 of this tire 2.

[0027] The base 8 may contain short fibers. The short fibers are obtained by cutting short a cord made of organic fibers. Preferred organic fibers include polyester fibers, nylon fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers. A mixture of multiple types of short fibers may be used.

[0028] This tire 2 may be provided with a skin layer that covers the side surfaces of the tread 6 and the base 8. At this time, the skin layer forms the side surface 14 of this tire 2. The skin layer is made of cross-linked rubber. The skin layer protects the tread 6 and the base 8.

[0029] FIG. 2(a) is a perspective view of the tire 2 of FIG. 1 as viewed from the inner peripheral surface 16 side, and FIG. 2(b) is a developed view of the inner peripheral surface 16 of the tire 2 of FIG. 1. In these figures, the double-headed arrow A indicates the circumferential direction of this tire 2, and the double-headed arrow X indicates the axial direction of the tire 2. FIG. 3(a) is a side view of the tire 2 of FIG. 1, and FIG. 3(b) is a cross-sectional view taken along line IIIb-IIIb of FIG. 1. In these figures, the double-headed arrow A indicates the circumferential direction of this tire 2, and the direction perpendicular to the paper surface is the axial direction of the tire 2. In FIG. 3(b), the rim R is omitted.

[0030] As shown in FIGS. 1 to 3, this tire 2 is provided with exhaust heat grooves 22 on the surface. The exhaust heat grooves 22 extend continuously across the inner peripheral surface 16 and the side surface 14. In other words, the exhaust heat grooves 22 include an inner peripheral portion 24 recessed from the inner peripheral surface 16 and a side portion 26 continuous with the inner peripheral portion 24 and recessed from the side surface 14. As shown in FIG. 1, in the radial direction, the outer end of the side portion 26 is located outside the outer end of the flange F of the rim R.

[0031] In the embodiments shown in FIGS. 1 to 3, there are a first exhaust heat groove 22a and a second exhaust heat groove 22b. The first exhaust heat groove 22a includes a first side portion 26a located on the first side surface 14a and a first inner peripheral portion 24a that is continuous with the first side portion 26a and is located on the inner peripheral surface 16. The second exhaust heat groove 22b includes a second side portion 26b located on the second side surface 14b and a second inner peripheral portion 24b that is continuous with the second side portion 26b and is located on the inner peripheral surface 16. As shown in FIG. 1, neither the first exhaust heat groove 22a nor the second exhaust heat groove 22b reaches the equatorial plane CL. In this embodiment, the circumferential position of the first inner peripheral portion 24a and the circumferential position of the second side portion 26b are the same. The circumferential position of the first inner peripheral portion 24a and the circumferential position of the second side portion 26b may be different.

[0032] As shown in FIGS. 2 and 3, a plurality of first exhaust heat grooves 22a and a plurality of second exhaust heat grooves 22b are all arranged at intervals in the circumferential direction. In this embodiment, the first exhaust heat grooves 22a and the second exhaust heat grooves 22b are arranged at equal intervals over the entire circumference of the tire 2. In this embodiment, a pair of the first exhaust heat groove 22a and the second exhaust heat groove 22b is arranged in the circumferential direction. The first exhaust heat groove 22a and the second exhaust heat groove 22b may be arranged alternately in the circumferential direction. The number of the first exhaust heat grooves 22a and the number of the second exhaust heat grooves 22b may be different.

[0033] The operation and effect of the present invention will be described below.

[0034] The cushion tire 2 according to the present invention includes an exhaust heat groove 22 having an inner peripheral portion 24 recessed from the inner peripheral surface 16 and a side portion 26 recessed from the side surface 14. In the radial direction, the outer end of the side portion 26 is located outside the outer end of the flange F of the rim R. The outer end of this exhaust heat groove 22 is not blocked by the rim R. The contact portion between the cushion tire 2 and the rim R is likely to generate heat. This exhaust heat groove 22 effectively discharges the heat generated at these contact portions to the outside. In this tire 2, an increase in temperature due to heat generation is suppressed.

[0035] Preferably, there are a first exhaust groove 22a having a first side portion 26a located on the first side surface 14a and a second exhaust groove 22b having a second side portion 26b located on the second side surface 14b. By doing so, heat can be discharged from both side surfaces 14 of the tire 2. In this tire 2, an increase in temperature due to heat generation is suppressed.

[0036] In a cushion tire, since it is used under a state where a large load is applied, "rim slip" may occur in which the tire 2 slides relative to the rim R when the vehicle starts, stops, accelerates, decelerates, etc.

[0037] Preferably, the first exhaust groove 22a and the second exhaust groove 22b do not reach the equatorial plane CL. The pressure from the tire 2 to the rim R at the position of the equatorial plane CL is important for realizing good rim slip resistance performance. Since the first exhaust groove 22a and the second exhaust groove 22b do not extend to the equatorial plane CL, this tire 2 maintains good rim slip resistance performance.

[0038] In FIG. 1, the double-headed arrow L1 represents the distance in the axial direction from the equatorial plane CL to the inner end of the first exhaust groove 22a. The ratio (L1 / W) of the distance L1 to the half-width W of the inner peripheral surface 16 of the tire 2 is preferably 25% or more. By setting the ratio (L1 / W) to 25% or more, good rim slip resistance performance is maintained. From this viewpoint, the ratio (L1 / W) is more preferably 30% or more. The ratio (L1 / W) is preferably 70% or less. By setting the ratio (L1 / W) to 70% or less, this first exhaust groove 22a effectively contributes to heat discharge. From this viewpoint, the ratio (L1 / W) is more preferably 66% or less.

[0039] In FIG. 1, the double-headed arrow L2 represents the distance in the axial direction from the equatorial plane CL to the inner end of the second exhaust groove 22b. The ratio (L2 / W) of the distance L2 to the half-width W of the inner peripheral surface 16 of the tire 2 is preferably 25% or more. By setting the ratio (L2 / W) to 25% or more, good rim slip resistance performance is maintained. From this viewpoint, the ratio (L2 / W) is more preferably 30% or more. The ratio (L2 / W) is preferably 70% or less. By setting the ratio (L2 / W) to 70% or less, the second exhaust groove 22b effectively contributes to heat dissipation. From this viewpoint, the ratio (L2 / W) is more preferably 66% or less.

[0040] In FIG. 1, the double-headed arrow K1 represents the distance in the radial direction from the outer end of the flange F to the outer end of the first exhaust groove 22a. From the viewpoint that the first exhaust groove 22a effectively contributes to heat dissipation, the distance K1 is preferably 5 mm or more. From the viewpoint of suppressing the influence on the appearance of the first exhaust groove 22a, the distance K1 is preferably 20 mm or less.

[0041] In FIG. 1, the double-headed arrow K2 represents the distance in the radial direction from the outer end of the flange F to the outer end of the second exhaust groove 22b. From the viewpoint that the second exhaust groove 22b effectively contributes to heat dissipation, the distance K2 is preferably 5 mm or more. From the viewpoint of suppressing the influence on the appearance of the second exhaust groove 22b, the distance K2 is preferably 20 mm or less.

[0042] FIG. 4 is a cross-sectional view in which the first exhaust groove 22a in FIG. 3(b) is enlarged. In FIG. 4, the double-headed arrow d1 represents the depth of the first exhaust groove 22a. From the viewpoint that the first exhaust groove 22a effectively contributes to heat dissipation, the depth d1 is preferably 2 mm or more, and more preferably 3 mm or more. From the viewpoint of maintaining good durability of the tire 2, the depth d1 is preferably 10 mm or less, and more preferably 8 mm or less.

[0043] From the viewpoint that the second exhaust groove 22b effectively contributes to heat dissipation, the depth d2 of the second exhaust groove 22b is preferably 2 mm or more, and more preferably 3 mm or more. From the viewpoint of maintaining good durability of the tire 2, the depth d2 is preferably 10 mm or less, and more preferably 8 mm or less.

[0044] In FIG. 4, the double-headed arrow wg1 represents the width of the first heat discharge groove 22a. The width wg1 is measured in a direction perpendicular to the direction in which the groove 12 extends on the inner peripheral surface 16. From the viewpoint that the first heat discharge groove 22a effectively contributes to heat discharge, the width wg1 is preferably 2 mm or more, and more preferably 3 mm or more. From the viewpoint of maintaining good anti-slip performance of the tire 2, the width wg1 is preferably 10 mm or less, and more preferably 8 mm or less.

[0045] From the viewpoint that the second heat discharge groove 22b effectively contributes to heat discharge, the width wg2 of the second heat discharge groove 22b is preferably 2 mm or more, and more preferably 3 mm or more. From the viewpoint of maintaining good anti-slip performance of the tire 2, the width wg2 is preferably 10 mm or less, and more preferably 8 mm or less.

[0046] The number N1 of the first heat discharge grooves 22a existing per 100 mm in the circumferential direction length measured along the inner peripheral surface 16 is preferably 2.0 or more. By setting the number N1 to 2.0 or more, these first heat discharge grooves 22a effectively contribute to heat discharge. From this viewpoint, the number N1 is more preferably 2.5 or more. The number N1 is preferably 5.0 or less. By setting the number N1 to 5.0 or less, good anti-rim slip performance is maintained. From this viewpoint, the number N1 is more preferably 4.5 or less.

[0047] The number N2 of the second heat discharge grooves 22b existing per 100 mm in the circumferential direction length measured along the inner peripheral surface 16 is preferably 2.0 or more. By setting the number N2 to 2.0 or more, these second heat discharge grooves 22b effectively contribute to heat discharge. From this viewpoint, the number N2 is more preferably 2.5 or more. The number N2 is preferably 5.0 or less. By setting the number N2 to 5.0 or less, good anti-rim slip performance is maintained. From this viewpoint, the number N2 is more preferably 4.5 or less.

[0048] [Second Embodiment] FIG. 5 is a cross-sectional view showing a cushion tire 30 according to another embodiment of the present invention together with a rim R. A set of the rim R and the cushion tire 30 mounted on the rim R constitutes an assembly 31. This tire 30 includes a tread 32 and a base 34. The structure of this tire 30 is the same as that of the tire 2 in FIG. 1 except for the shape of the exhaust heat groove 36.

[0049] As shown in FIG. 5, the exhaust heat groove 36 of this tire 30 includes a first side portion 40a recessed from the first side surface 44a, an inner peripheral portion 38 recessed from the inner peripheral surface 42, and a second side portion 40b recessed from the second side surface 44b. The inner peripheral portion 38 is continuous with the first side portion 40a and the second side portion 40b. In the radial direction, each side portion 40 is located outside the outer end of the flange F of the rim R.

[0050] FIG. 6 is a developed view of the inner peripheral surface 42 of the tire 30 in FIG. 5. As shown in FIGS. 5 and 6, the inner peripheral portion 38 extends in the axial direction from one end to the other end of the inner peripheral surface 42. As shown in FIG. 6, a plurality of exhaust heat grooves 36 are arranged side by side at intervals in the circumferential direction.

[0051] In this cushion tire 30, as described above, the inner peripheral portion 38 extends from one end to the other end of the inner peripheral surface 42. This inner peripheral portion 38 is connected to a first side portion 40a recessed from the first side surface 44a and a second side portion 40b recessed from the second side surface 44b. Since both side portions 40 are connected to the inner peripheral portion 38, this exhaust heat groove 36 can effectively discharge heat. In this tire 30, an increase in temperature due to heat generation is suppressed.

[0052] [Third Embodiment] FIG. 7 is a cross-sectional view showing a cushion tire 50 according to still another embodiment of the present invention together with a rim R. A set of the rim R and the cushion tire 50 mounted on the rim R constitutes an assembly 51. This tire 50 includes a tread 52 and a base 54. The structure of this tire 50 is the same as that of the tire 2 in FIG. 1 except for the shape of the base 54.

[0053] As shown in FIG. 7, the base 54 has increased thickness at both outer axial portions. These portions with increased thickness extend in the circumferential direction. In other words, the base 54 includes a first outer portion 54a extending in the circumferential direction, a second outer portion 54b extending in the circumferential direction, and a central portion 54c located between the first outer portion 54a and the second outer portion 54b and extending in the circumferential direction. In the radial direction, the thickness of the first outer portion 54a is greater than the thickness of the central portion 54c, and the thickness of the second outer portion 54b is greater than the thickness of the central portion 54c.

[0054] In the axial direction, the position of the inner side surface 56 of the first outer portion 54a is substantially the same as the position of the inner end of the first exhaust groove 60a. Specifically, the distance M1 between the position of the inner side surface 56 of the first outer portion 54a and the position of the inner end of the first exhaust groove 60a in the axial direction is 5% or less of the half-width W of the inner circumferential surface 62. The first exhaust groove 60a is substantially provided on the inner circumferential surface 62 of the first outer portion 54a. In the embodiment of FIG. 7, the distance M1 is zero.

[0055] In the axial direction, the position of the inner side surface 58 of the second outer portion 54b is substantially the same as the position of the inner end of the second exhaust groove 60b. Specifically, the distance M2 between the position of the inner side surface 58 of the second outer portion 54b and the position of the inner end of the second exhaust groove 60b in the axial direction is 5% or less of the half-width W of the inner circumferential surface 62. The second exhaust groove 60b is substantially provided on the inner circumferential surface 62 of the second outer portion 54b. In the embodiment of FIG. 7, the distance M2 is zero.

[0056] In the cushion tire 50 of this embodiment, as described above, the first exhaust groove 60a is provided substantially on the inner peripheral surface 62 of the first outer portion 54a. The radial thickness of the first outer portion 54a is larger than the radial thickness of the central portion 54c. The base 54 is more difficult to deform than the tread 52. The first outer portion 54a, which is the thickened portion of the base 54, contributes to the high contact pressure of the tire 50 on the rim R. Despite the reduction in the contact area between the inner peripheral surface 62 of the tire 50 and the bottom surface 64 of the rim R due to the first exhaust groove 60a, by increasing the thickness of the first outer portion 54a, good rim slip resistance performance is achieved. In this tire 50, good rim slip resistance performance is achieved.

[0057] In this cushion tire 50, as described above, the second exhaust groove 60b is provided substantially on the inner peripheral surface 62 of the second outer portion 54b. The radial thickness of the second outer portion 54b is larger than the radial thickness of the central portion 54c. The thick second outer portion 54b contributes to the high contact pressure of the tire 50 on the rim R. Despite the reduction in the contact area between the inner peripheral surface 62 of the tire 50 and the bottom surface 64 of the rim R due to the second exhaust groove 60b, by increasing the thickness of the second outer portion 54b, good rim slip resistance performance is achieved. In this tire 50, good rim slip resistance performance is achieved.

[0058] In FIG. 7, the double-headed arrow H1 represents the radial thickness of the first outer portion 54a. The thickness H1 is measured at the axial center of the first outer portion 54a. The double-headed arrow Hc represents the radial thickness of the central portion 54c. The thickness Hc is measured at the equatorial plane CL. The ratio (H1 / Hc) of the thickness H1 to the thickness Hc is preferably 1.2 or more. By setting the ratio (H1 / Hc) to 1.2 or more, good rim slip resistance performance is achieved. The ratio (H1 / Hc) is preferably 1.4 or less. By setting the ratio (H1 / Hc) to 1.4 or less, the tread 52 has a sufficient thickness. This tread 52 contributes to good ride comfort and wear resistance.

[0059] In FIG. 7, the double-headed arrow H2 represents the radial thickness of the second outer portion 54b. The thickness H2 is measured at the axial center of the second outer portion 54b. The ratio (H2 / Hc) of the thickness H2 to the thickness Hc is preferably 1.2 or more. By setting the ratio (H2 / Hc) to 1.2 or more, good anti-rim slip performance is achieved. The ratio (H2 / Hc) is preferably 1.4 or less. By setting the ratio (H2 / Hc) to 1.4 or less, the tread 52 has a sufficient thickness. This tread 52 contributes to good ride comfort and wear resistance.

[0060] [Fourth Embodiment] FIG. 8 is a cross-sectional view showing a cushion tire 70 according to still another embodiment of the present invention together with a rim R. A set of the rim R and the cushion tire 70 mounted on this rim R constitutes an assembly 71. FIG. 9 is a developed view of the inner peripheral surface 78 of the tire 70 in FIG. 8. FIG. 10(a) is a side view of the tire 70 in FIG. 8, and FIG. 10(b) is a cross-sectional view taken along line Xb-Xb in FIG. 8. In FIG. 10(b), the rim R is omitted. This tire 70 includes a tread 72 and a base 74. The structure of this tire 70 is the same as that of the tire 2 in FIG. 1 except that longitudinal grooves described below are provided on the inner peripheral surface 78.

[0061] As shown in FIGS. 8 - 11, in addition to the first exhaust groove 80a and the second exhaust groove 80b, longitudinal grooves 82 extending in the circumferential direction are provided on the inner peripheral surface 78 of this tire 70. In this embodiment, two longitudinal grooves 82 are provided. These longitudinal grooves 82 are provided at positions symmetric with respect to the equatorial plane CL. Each longitudinal groove 82 is connected to at least one exhaust groove 80. In this embodiment, one longitudinal groove 82 is connected to the first exhaust groove 80a, and the other longitudinal groove 82 is connected to the second exhaust groove 80b. Each longitudinal groove 82 is connected to the corresponding exhaust groove 80 at the axially inner end of the exhaust groove 80. The longitudinal groove 82 may be connected to the exhaust groove 80 outside the axially inner end of the exhaust groove 80.

[0062] As shown in FIG. 9, in this embodiment, one of the longitudinal grooves 82 is connected to a plurality of first exhaust grooves 80a arranged in the circumferential direction. The other longitudinal groove 82 is connected to a plurality of second exhaust grooves 80b arranged in the circumferential direction. In this embodiment, each longitudinal groove 82 is ring-shaped.

[0063] The number of the longitudinal grooves 82 may be 1. Three or more longitudinal grooves 82 may be provided.

[0064] The cushion tire 70 of this embodiment includes longitudinal grooves 82 extending in the circumferential direction on the inner peripheral surface 78. The longitudinal grooves 82 are connected to at least one exhaust groove 80. Through the longitudinal grooves 82 and the exhaust grooves 80, the heat generated at the contact portion between the tire 70 and the rim R is effectively discharged. In this tire 70, the temperature rise due to heat generation is suppressed.

[0065] Preferably, a longitudinal groove 82 connected to the first exhaust groove 80a and a longitudinal groove 82 connected to the second exhaust groove 80b are provided. Each longitudinal groove 82 is preferably connected to a plurality of exhaust grooves 80. By doing so, the heat generated at the contact portion between the tire 70 and the rim R is effectively discharged. In this tire 70, the temperature rise due to heat generation is suppressed.

[0066] Preferably, the longitudinal groove 82 is not located on the equatorial plane CL. The pressure of the base 74 on the rim R at the position of the equatorial plane CL is important for maintaining good anti-rim slip performance. By the longitudinal groove 82 not being located on the equatorial plane CL, this tire 70 maintains good anti-rim slip performance.

[0067] In FIG. 8, the double-headed arrow Lv represents the distance from the equatorial plane CL in the axial direction to the inner end of the longitudinal groove 82. The ratio (Lv / W) of the distance Lv to the half-width W of the inner peripheral surface 78 of the tire 70 is preferably 25% or more. By setting the ratio (Lv / W) to 25% or more, good rim slip resistance performance is maintained. From this perspective, the ratio (Lv / W) is more preferably 30% or more. The ratio (Lv / W) is preferably 70% or less. By setting the ratio (Lv / W) to 70% or less, this longitudinal groove 82 effectively contributes to heat dissipation. From this perspective, the ratio (Lv / W) is more preferably 66% or less.

[0068] The longitudinal groove 82 preferably has a ring shape. At this time, from the perspective that the longitudinal groove 82 effectively contributes to heat dissipation, the number of longitudinal grooves 82 is preferably 2 or more. From the perspective of maintaining good slip resistance performance of the tire 70, the number of longitudinal grooves 82 is preferably 4 or less.

[0069] From the perspective that the longitudinal groove 82 effectively contributes to heat dissipation, the depth of the longitudinal groove 82 is preferably 2 mm or more, and more preferably 3 mm or more. From the perspective of maintaining good durability of the tire 70, the depth of the longitudinal groove 82 is preferably 10 mm or less, and more preferably 8 mm or less.

[0070] From the perspective that the longitudinal groove 82 effectively contributes to heat dissipation, the width of the longitudinal groove 82 is preferably 2 mm or more, and more preferably 3 mm or more. From the perspective of maintaining good slip resistance performance of the tire 70, the width of the longitudinal groove 82 is preferably 10 mm or less, and more preferably 8 mm or less.

[0071] [Fifth Embodiment] Figure 11 is a cross-sectional view showing a cushion tire 90 according to still another embodiment of the present invention together with a rim R. A set of the rim R and the cushion tire 90 mounted on the rim R constitutes an assembly 91. FIG. 12(a) is a side view of the tire 90 of FIG. 11, and FIG. 12(b) is a cross-sectional view taken along line XIIb-XIIb of FIG. 11. In FIG. 12(b), the rim R is omitted. This tire 90 includes a tread 92, a base 94, and a bead 96. On the inner peripheral surface 98 of this tire 90, a first exhaust groove 100a, a second exhaust groove 100b, and a longitudinal groove 102 are provided. The structure of this tire 90 is the same as that of the tire 50 of FIG. 7 except that it includes a bead 96 and a longitudinal groove 102.

[0072] As shown in FIG. 11, the bead 96 is embedded inside the base 94. In this embodiment, two beads 96 are provided. These beads 96 are provided at positions symmetric with respect to the equatorial plane CL. As shown in FIG. 12(b), each bead 96 extends in the circumferential direction. The bead 96 is ring-shaped. The bead 96 includes a wound non-elastic wire. A typical material of the wire is steel. The bead 96 improves the force with which the tire 90 tightens the rim R. The bead 96 contributes to preventing rim slip.

[0073] As shown in FIG. 11, in this embodiment, each bead 96 has a radial overlap with the corresponding longitudinal groove 102. That is, in the axial direction, a part or all of the corresponding bead 96 is included in a region that extends radially within the region between the outer end and the inner end of the longitudinal groove 102.

[0074] The number of beads 96 may be one. Three or more beads 96 may be provided.

[0075] The cushion tire 90 of this embodiment includes a bead 96 that is embedded inside the base 94 and extends in the circumferential direction. The bead 96 contributes to the tightening force of this tire 90 on the rim R. In this tire 90, good rim slip resistance performance is realized.

[0076] The bead 96 and the longitudinal groove 102 preferably overlap in the radial direction. The bead 96 contributes to the clamping force of this tire 90 to the rim R. By positioning the bead 96 so as to overlap the longitudinal groove 102 in the radial direction, good rim slip resistance performance is achieved despite the reduction in the contact area between the inner peripheral surface 98 of the tire 90 and the bottom surface 104 of the rim R due to the longitudinal groove 102. In this tire 90, good rim slip resistance performance is achieved.

[0077] In FIG. 11, the double-headed arrow Lb represents the distance in the axial direction from the equatorial plane CL to the inner end of the bead 96. From the viewpoint of effectively contributing to the clamping force of the rim R, the ratio (Lb / W) of the distance Lb to the half-width W of the inner peripheral surface 98 of the tire 90 is preferably 80% or less.

[0078] From the viewpoint of achieving good slip resistance performance of the tire 90, the number of beads 96 is preferably 2 or more. From the viewpoint of suppressing the influence of the bead 96 on the mass of the tire 90, the number of beads 96 is preferably 4 or less.

[0079] [Other Embodiments] FIG. 13 shows the inner peripheral portion of the exhaust heat groove of a cushion tire according to still another embodiment. These are development views of the inner peripheral surface of the cushion tire.

[0080] In the tire 120 of FIG. 13(a), the inner peripheral portion 122 extends from the end of the inner peripheral surface 124 toward the inner side in the axial direction while inclining forward in the rotational direction of the tire 120 when the vehicle moves forward. The axially inner end of the inner peripheral portion 122 is located forward in the rotational direction with respect to the axially outer end of the inner peripheral portion 122. When the vehicle moves forward, in this inner peripheral portion 122, it contacts the ground first from the axially inner end side. Thereby, the air in the inner peripheral portion 122 is effectively discharged. This exhaust heat groove effectively discharges heat to the outside. The inner peripheral portion 122 may extend from the end of the inner peripheral surface 124 toward the inner side in the axial direction while inclining forward in the rotational direction of the tire 120 when the vehicle moves backward. When the vehicle moves backward, in this inner peripheral portion 122, it contacts the ground first from the axially inner end side. Thereby, the air in the inner peripheral portion 122 is effectively discharged.

[0081] In the tire 128 of FIG. 13(b), the inner peripheral portion 130 extends while bending forward in the rotational direction of the tire 128 when the vehicle moves forward, from the end of the inner peripheral surface 132 toward the inner side in the axial direction. When the vehicle moves forward, in this inner peripheral portion 130, it contacts the ground first from the axially inner end side. Thereby, the air in the inner peripheral portion 130 is effectively discharged. The inner peripheral portion 130 may extend while bending forward in the rotational direction of the tire 128 when the vehicle moves backward, from the end of the inner peripheral surface 132 toward the inner side in the axial direction. When the vehicle moves backward, in this inner peripheral portion 130, it contacts the ground first from the axially inner end side. Thereby, the air in the inner peripheral portion 130 is effectively discharged. In FIG. 13(b), the inner peripheral portion 130 is bent in an arc shape, but the inner peripheral portion 130 may be bent in a polygonal line shape.

[0082] In the tire 133 of FIG. 13(c), the inner peripheral portion 134 has a U-shape having both end points at the end of the inner peripheral surface 136. In this inner peripheral portion, the air in the inner peripheral portion 134 is effectively discharged in both the case where the vehicle moves forward and the case where the vehicle moves backward. This exhaust heat groove effectively discharges heat to the outside.

[0083] In the foregoing embodiment, the side portions of the exhaust heat grooves extend linearly and radially outward. The side portions do not necessarily have to extend linearly and radially outward. Although not shown, the side portions may extend while being inclined forward or backward in the rotational direction of the tire toward the outside in the radial direction. The side portions may bend midway. The side portions may have other shapes.

Example

[0084] Hereinafter, the effects of the present invention will be clarified by examples, but the present invention should not be construed in a limited manner based on the description of these examples.

[0085] [Example 1] A cushion tire of Example 1 having the specifications shown in Table 1 below was obtained. This tire has the configuration shown in FIG. 1. This is shown as "FIG. 1" in the column of "Configuration Diagram" in Table 1. The size of the tire was "21X8-9". In this tire, the base does not contain short fibers. The depths of both the first exhaust heat groove and the second exhaust heat groove were 5 mm, and the widths of both the first exhaust heat groove and the second exhaust heat groove were 5 mm. The number N1 of the first exhaust heat grooves and the number N2 of the second exhaust heat grooves were made the same. In Table 1, these values are collectively described as "number N". The ratios (L1 / W) and (L2 / W) of the first exhaust heat groove and the second exhaust heat groove, respectively, were made the same value. In Table 1, these values are collectively described as ratio (L / W). The ratios (H1 / Hc) and (H2 / Hc) were made the same value. In Table 1, these values are collectively described as ratio (H / Hc).

[0086] [Comparative Example 1] A tire of Comparative Example 1 was obtained in the same manner as in Example 1 except that no exhaust heat groove was provided.

[0087] [Example 2] In the tire of Example 2, both the first exhaust heat groove and the second exhaust heat groove extend to the equatorial plane and are connected at the equatorial plane. In Table 1, this is represented by a ratio (L / W) of 0. This is the tire shown in FIG. 5. The tire of Example 2 is the same as Example 1 in other respects.

[0088] [Example 3] A tire of Example 3 was obtained in the same manner as in Example 1, except that the ratio (L / W) was as shown in Table 1.

[0089] [Examples 4 - 5] Tires of Examples 4 - 5 were obtained in the same manner as in Example 3, except that the ratio (H / Hc) was as shown in Table 1. These are the tires shown in FIG. 7.

[0090] [Example 6] In the tire of Example 6, two longitudinal grooves were provided. The depth of the longitudinal grooves was 5 mm and the width was 5 mm. One of these was connected to the first exhaust groove and the other was connected to the second exhaust groove. These longitudinal grooves were provided at positions symmetric with respect to the equatorial plane. The value of the ratio (Lv / W) of these longitudinal grooves is shown in Table 2 as the longitudinal groove position. The tire of Example 6 is the same as that of Example 1 in other respects. This is the tire shown in FIG. 8.

[0091] [Example 7] In the tire of Example 7, two beads were provided. These beads were provided at positions symmetric with respect to the equatorial plane. The value of the ratio (Lb / W) is shown in Table 2 as the bead position. The tire of Example 7 is the same as that of Example 6 in other respects.

[0092] [Example 8] A tire of Example 8 was obtained in the same manner as in Example 7, except that the bead position was as shown in Table 2. In this tire, each bead has an overlap in the radial direction with the corresponding longitudinal groove.

[0093] [Example 9] In the tire of Example 9, four longitudinal grooves were provided. Two of these longitudinal grooves are located on one side surface side with respect to the equatorial plane and are connected to the first exhaust groove, and the other two are located on the other side surface side and are connected to the second exhaust groove. These are provided at positions symmetric with respect to the equatorial plane. The positions of the longitudinal grooves closer to the equatorial plane and the positions of the longitudinal grooves farther from the equatorial plane are shown in Table 2 by the value of the ratio (Lv / W).

[0094] In the tire of Example 9, four beads were further provided. Two of these longitudinal grooves are located on one side surface side with respect to the equatorial plane, and the other two are located on the other side surface side. These are provided at symmetric positions with respect to the equatorial plane. The positions of the bead closer to the equatorial plane and the bead farther from it are shown in Table 2 by the value of the ratio (Lb / W). The tire of Example 9 is the same as that of Example 8 except for this.

[0095] [Example 10] A tire of Example 10 was obtained in the same manner as in Example 8 except that the ratio (H / Hc) was as shown in Table 2. This is the tire shown in FIG. 11.

[0096] [Example 11] A tire of Example 11 was obtained in the same manner as in Example 10 except that the ratios (L / W) and (Lv / W) were as shown in Table 2.

[0097] [Evaluation of Rim Slip] The tire was mounted on a rim (size: 9×6.00E TB), and this tire was mounted on the driving wheels of a vehicle (a counterweight type forklift with a load capacity of 2.5 t). No load was loaded on the vehicle. With this vehicle, slalom driving was repeated on a flat asphalt road surface. The speed of the vehicle at this time was 8 km / h, and the driving time was 2 hours. Then, the length by which the tire slipped with respect to the rim was measured. The results are shown in Table 1-2. The smaller the numerical value, the more preferable. In other words, the smaller this numerical value, the better the performance of preventing rim slip.

[0098] [Tire Temperature] For the tire immediately after driving in the evaluation of the rim slip, the temperature inside the tire was measured. A hole was drilled from the center of the tread surface toward the inner side in the radial direction, and the temperature was measured at a position 10 mm inward in the radial direction from the boundary position between the base and the tread. The results are shown in Table 1-2. The smaller the numerical value, the more preferable.

[0099]

Table 1

[0100]

Table 2

[0101] As shown in Table 1-2, in the tire of the example, the temperature rise due to heat generation is suppressed. From this evaluation result, the superiority of the present invention is clear.

Industrial Applicability

[0102] The tire according to the present invention can be mounted on an industrial vehicle.

Explanation of Signs

[0103] 2, 30, 50, 70, 90... Cushion tire 4, 31, 51, 91... Assembly 6, 32, 52, 72, 92... Tread 8, 34, 54, 74, 94... Base 12... Groove 14, 44... Side 14a, 44a... First side 14b, 44b... Second side 16, 42, 62, 78, 98... Inner peripheral surface 20, 64, 104... Bottom surface 22, 36, 60, 80... Exhaust groove 22a, 60a, 80a, 100a... First exhaust groove 22b, 60b, 80b, 100b... Second exhaust groove 24, 38... Inner peripheral part 24a... First inner peripheral part 24b... Second inner peripheral part 26, 40... Side part 26a, 40a... First side part 26b, 40b... Second side part 28... Tread surface 54a... First outer side part 54b ··· Second outer part 54c ··· Central part 56 ··· Side surface of the first outer part 58 ··· Side surface of the second outer part 96 ··· Bead 82, 102 ··· Longitudinal groove

Claims

1. A cushion tire having a surface including a first side surface, a second side surface, and an inner circumferential surface, and being mounted on a rim, wherein the cushion tire has one or more exhaust grooves on the surface, each exhaust groove (1) is recessed from the first side surface or the second side surface, and a side portion whose outer end in the radial direction is located outside the outer end of the flange of the rim and (2) is recessed from the inner circumferential surface and is an inner circumferential portion continuous with the side portion and the inner circumferential portion does not reach either the first side surface or the second side surface.

2. The tire has (1) a first side portion recessed from the first side surface, the inner circumferential portion being continuous with the first side portion and not reaching the equatorial plane, a first exhaust groove and (2) a second side portion recessed from the second side surface, the inner circumferential portion being continuous with the second side portion and not reaching the equatorial plane, a second exhaust groove The cushion tire according to claim 1.

3. In the axial direction, the ratio (L1 / W) of the distance L1 from the equatorial plane to the inner end of the first exhaust groove to the half-width W of the inner circumferential surface is 25% or more, The cushion tire according to claim 2, wherein the ratio (L2 / W) of the distance L2 from the equatorial plane to the inner end of the second exhaust groove to the half-width W is 25% or more.

4. Comprising a base in contact with the rim and a tread located radially outside the base, the base has a first outer portion extending in the circumferential direction and having a position of its inner side surface substantially the same as the position of the inner end of the first exhaust groove in the axial direction, a second outer portion extending in the circumferential direction and having a position of its inner side surface substantially the same as the position of the inner end of the second exhaust groove in the axial direction, and a central portion extending in the circumferential direction and located between the first outer portion and the second outer portion, The cushion tire according to claim 2 or 3, wherein the radial thickness of the first outer portion and the radial thickness of the second outer portion are both greater than the radial thickness of the central portion.

5. The cushion tire according to claim 4, wherein the thickness of the first outer portion is 1.2 times or more and 1.4 times or less the thickness of the central portion, and the thickness of the second outer portion is 1.2 times or more and 1.4 times or less the thickness of the central portion.

6. The cushion tire according to any one of claims 2 to 5, wherein a plurality of the first row of heat discharge grooves are arranged at intervals in the circumferential direction, and a plurality of the second row of heat discharge grooves are arranged at intervals in the circumferential direction.

7. A cushion tire having a surface including a first side surface, a second side surface, and an inner circumferential surface, and being mounted on a rim, wherein the cushion tire has one or more rows of heat discharge grooves on the surface, each heat discharge groove (1) a side portion recessed from the first side surface or the second side surface and having an outer end thereof located radially outside the outer end of the flange of the rim, and (2) an inner circumferential portion recessed from the inner circumferential surface and continuous with the side portion and having, wherein a longitudinal groove extending in the circumferential direction is provided on the inner circumferential surface, wherein the longitudinal groove is connected to at least one heat discharge groove, wherein the longitudinal groove is not located on the equatorial plane, a cushion tire, wherein in the axial direction, a ratio (Lv / W) of a distance Lv from the equatorial plane to an inner end of the longitudinal groove to a half width W of the inner circumferential surface is 25% or more.

8. A base in contact with the rim, a tread located radially outside the base, and a bead embedded in the base and extending in the circumferential direction, the cushion tire according to claim 7, wherein the bead and the longitudinal groove overlap in the radial direction.

9. wherein the heat discharge groove has a first side portion recessed from the first side surface and a second side portion recessed from the second side surface, the cushion tire according to claim 7 or 8, wherein the inner circumferential portion is continuous with the first side portion and continuous with the second side portion.

10. The cushion tire according to any one of claims 7 to 9, wherein a plurality of the heat discharge grooves are arranged at intervals in the circumferential direction.

11. A rim having a flange and a cushion tire mounted on the rim and having a surface including a first side surface, a second side surface, and an inner circumferential surface, wherein the cushion tire has one or more rows of heat discharge grooves on the surface, each heat discharge groove (1) a side portion recessed from the first side surface or the second side surface and having an outer end thereof located radially outside the outer end of the flange of the rim, and (2) an inner circumferential portion recessed from the inner circumferential surface and continuous with the side portion and having, an assembly, wherein the inner circumferential portion does not reach either the first side surface or the second side surface.

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