KR101654942B1 - Pneumatic tire - Google Patents

Abstract

The present invention provides a pneumatic tire (16) that is of high quality and can prevent damage to the rim flange (38).
The pneumatic tire 16 of the present invention includes a tread 18, a bead 22, a carcass 24, a support layer 26, a belt 28, a band 30 and a side portion 36. The side portion 36 has a sidewall 56, a clinch portion 58, and an insert 60. The insert 60 is surrounded by the carcass 24, the sidewall 56, and the clinch portion 58. The insert 60 is not exposed on the surface of the side portion 36. The minimum value of the distance between the surface of the side portion 36 and the insert 60 is 1.0 mm or more. The insert 60 is made of soft rubber. The JIS-A hardness H2 of the insert 60 is 70 or less. The difference (H1-H2) between the hardness H1 of the clinch portion 58 and the hardness H2 of the insert 60 is 2 or more.

Description

Pneumatic tire {PNEUMATIC TIRE}

The present invention relates to a pneumatic tire. In particular, the present invention relates to a tire comprising a rim protector.

Tires are mounted on the rim. Rims include flanges. On the road with the sidewalk, a curb is laid between the sidewalk and the sidewalk. When the vehicle approaches the shoulder, the rim flange may contact the curb. The rim may be damaged by contact. There is a road with Cat's Eye on the road. When a tire rides over this cat, the tire is over-deformed and the rim flange collides with the cat's eye. This collision can damage the rim. In a tire with a small flatness, the distance between the road surface and the rim flange is short. In a rim equipped with a tire with a low flatness, the flange and the curb are likely to come into contact. In the rim equipped with tires with a low flatness, the flange and cat eye are likely to collide.

In Fig. 3, a conventional tire 2 is shown. The side portion 4 of the tire 2 includes a sidewall 6 and a clinch portion 8. The side portion (4) protrudes in a tapered shape toward the outside in the axial direction. The rim protector 10 is formed by projecting in this manner. When the vehicle approaches the shoulder, the rim protector 10 comes into contact with the curb in preference to the rim flange 12. The rim protector 10 is interposed between the cat's eye and the rim flange 12 when the tires 2 ride over the cat's eye. The rim protector (10) prevents damage to the rim flange (12). A tire including a rim protector is disclosed in Japanese Patent Application Laid-Open No. 2003-326921.

Patent Document 1: JP-A-2003-326921

In the tire 2 shown in Fig. 3, the rim protector 10 is constituted by a part of the side wall 6 and a part of the clinch portion 8. Most of the rim protector 10 is the clinch portion 8. Generally, the clinch portion 8 is made of rubber having a high hardness. Therefore, the rigidity of the rim protector 10 is large. The rolling resistance of the tire 2 including the rim protector 10 is large. Therefore, the tire 2 hinders the fuel-efficient performance of the vehicle. The rim protector (10) makes the longitudinal stiffness of the tire (2) excessively large. Therefore, the ride feeling of the tire 2 falls. The rim protector 10 causes uneven deformation of the side portion 4 of the tire 2. Therefore, the steering stability of the tire 2 is poor.

An object of the present invention is to provide a pneumatic tire which is of high quality and can prevent damage to the rim flange.

A pneumatic tire according to the present invention comprises a tread having an outer surface forming a tread surface, a pair of beads each located radially substantially inward of an end of the tread, and a pair of beads extending between one bead and the other bead, And a side portion located on the outer side of the carcass in the axial direction, respectively. Each of the side portions has a rim protector protruding in a tapered manner toward the axially outward side. The side portion includes an insert made of a soft rubber in the vicinity of the rim protector.

The side portion may be provided with a side wall and a clinch portion. Preferably, the insert is covered by this side wall or the clinch portion.

Preferably, the JIS-A hardness H2 of the insert is smaller than the JIS-A hardness H1 of the clinch portion. Preferably, the difference (H1-H2) between the hardness H1 and the hardness H2 is 2 or more. Preferably, the minimum value of the distance between the surface of the side portion and the insert is 1.0 mm or more.

In the pneumatic tire according to the present invention, the rim protector prevents the rim flange from being damaged. Since the tire includes an insert made of a soft rubber, the rolling resistance is small, and ride comfort and steering stability are excellent.

1 is a sectional view showing a part of a pneumatic tire according to an embodiment of the present invention.
Fig. 2 is an enlarged sectional view showing a part of the tire of Fig. 1; Fig.
3 is a sectional view showing a part of a conventional tire.

Best Mode for Carrying Out the Invention Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the appropriate drawings.

The tire 16 shown in Figures 1 and 2 includes a tread 18, a wing 20, a bead 22, a carcass 24, a support layer 26, a belt 28, a band 30, An inner liner 32, a chaff 34, and a side portion 36. The tire 16 is a tubeless type. The center line CL shown in Fig. 1 represents the equator of the tire 16. The tire 16 has a substantially symmetrical shape with respect to the equator CL. 2 also shows the flange 38 of the rim on which the tire 16 is mounted.

The tread 18 is made of a crosslinked rubber having excellent abrasion resistance. The tread 18 has a convex shape radially outwardly. The tread 18 includes a tread surface. This tread surface is grounded with the road surface.

The bead 22 is located radially more inward than the end of the tread 18. The bead 22 includes a core 40 and an apex 42 extending radially outwardly from the core 40. The core 40 is ring-shaped. The core 40 is wound with a non-stretchable wire. Typically, a steel wire is used for the core 40. The tip of the Apex 42 is tapered toward the outer side in the radial direction. The apte 42 is made of a crosslinked rubber having a high hardness.

The carcass 24 is located inside the tread 18 in the radial direction. The carcass 24 is made up of a carcass ply 44. The carcass ply 44 extends between the beads 22 on both sides. The carcass ply 44 is folded around the core 40 from the axially inward side to the outward side. Although not shown, the carcass ply 44 consists of a plurality of cords in parallel and topping rubber. The absolute value of the angle formed by each code with respect to the equatorial plane is usually 70 ° to 90 °. In other words, the carcass 24 has a radial structure.

The support layer 26 is located inside the carcass 24 in the axial direction. The support layer 26 is between the carcass 24 and the inner liner 32. As shown in Fig. 2, the support layer 26 is tapered toward the inner side in the radial direction and tapered toward the outer side. This support layer 26 has a shape similar to the crescent moon. The support layer 26 is made of a crosslinked rubber having a high hardness. When the tire 16 is punctured, the support layer 26 supports the load. The support layer 26 is not essential.

The belt 28 is located radially outward of the carcass 24. The belt 28 is laminated with the carcass 24. The belt 28 reinforces the carcass 24. The belt 28 consists of an inner layer 46 and an outer layer 48. Although not shown, each of the inner layer 46 and the outer layer 48 is comprised of a plurality of cords in parallel and topping rubber. Each code is tilted with respect to the equatorial plane. The absolute value of the tilt angle is 10 degrees or more and 35 degrees or less. The tilting direction of the cord of the inner layer (46) is opposite to the tilting direction of the cord of the outer layer (48).

The band (30) covers the belt (28). Although not shown, the band 30 is made of cord and topping rubber. The cord extends substantially circumferentially and is wound in a spiral. The band 30 has a so-called jointless structure. Since the belt 28 is restrained by this cord, lifting of the belt 28 is suppressed.

The side portion 36 is located outside the carcass 24 in the axial direction. The side portion 36 protrudes in a tapered shape toward the outer side in the axial direction. By protruding in this manner, a rim protector 50 is formed on the side portion 36. [ The end face 52 of the rim protector 50 is located outside the end portion 54 of the flange 38 in the axial direction.

When the driver turns the steering wheel of the vehicle and the vehicle approaches the shoulder, the rim protector 50 comes into contact with the curb. This contact causes a reaction force to the handle. By this reaction force, the driver detects contact between the curb and the tire 16. By turning the handle in the opposite direction by the driver, contact between the rim flange 38 and the curb is avoided. The rim protector (50) prevents damage to the flange (38).

The rim protector 50 is interposed between the cat's eye and the flange 38 when the tire 16 is greatly deformed over the cat's eye. Collision between the flange 38 and the cat's eye is prevented by the rim protector 50. The rim protector (50) prevents damage to the flange (38).

The side portion 36 includes a sidewall 56, a clinch portion 58, and an insert 60. Sidewall 56 extends radially substantially inwardly from the end of tread 18. [ The sidewall 56 is made of a crosslinked rubber. The sidewalls 56 absorb the impact from the road surface by bending. The sidewalls 56 also prevent trauma to the carcass 24. The clinch portion 58 is made of a crosslinked rubber having a high hardness. 2, the clinch portion 58 contacts the flange 38. As shown in Fig.

The insert 60 is generally triangular. The insert 60 is tapered outwardly in the axial direction. The insert 60 is surrounded by the carcass 24, the sidewall 56, and the clinch portion 58. The insert 60 may be spaced apart from the carcass 24.

The insert 60 is made of soft rubber. Since the side portion 36 has the insert 60, the rigidity of the side portion 36 is not excessive, although the rim protector 50 is present. Although the side portion 36 has the rim protector 50, the rolling resistance of the tire 16 is small. Therefore, the tire 16 can contribute to the fuel consumption of the vehicle. Although the side portion 36 has the rim protector 50, the longitudinal stiffness of the tire 16 is small. Therefore, the tire 16 is excellent in ride comfort. Although the side portion 36 has the rim protector 50, the deformation of the side portion 36 is uniform. Therefore, the tire 16 is excellent in steering stability.

The insert 60 is obtained by crosslinking the rubber composition. (EN), polybutadiene (BR), styrene-butadiene copolymer (SBR), polyisoprene (IR), isobutylene-isoprene copolymer (IIR), acrylonitrile-butadiene copolymer (NBR), polychloroprene (CR), styrene-isoprene-butadiene copolymer (SIBR), styrene-isoprene copolymer and isoprene-butadiene copolymer. Two or more kinds of rubber may be used in combination. From the viewpoint of crack resistance and processability, a diene rubber is preferable. The ratio of the amount of the diene rubber to the total amount (total amount) of the base rubber is preferably not less than 40% by mass, particularly preferably not less than 60% by mass.

The rubber composition comprises sulfur. The rubber molecules are cross-linked by sulfur. Other crosslinking agents may be used with or in place of sulfur. Crosslinking may be performed by an electron beam.

Preferably, the rubber composition comprises a vulcanization accelerator together with sulfur. A sulfenamide vulcanization accelerator, a thiazole vulcanization accelerator, a thiuram vulcanization accelerator, a dithiocarbamate vulcanization accelerator and the like can be used. A preferred vulcanization accelerator is a sulfenamide vulcanization accelerator. Specific examples of the sulfenamide-based vulcanization accelerator include N-cyclohexyl-2-benzothiazolylsulfenamide, N-tert-butyl-2-benzothiazolylsulfenamide and N, N'-dicyclohexyl- And thiazolyl sulfenamide.

The rubber composition comprises a reinforcing material. A typical stiffener is carbon black. FEF, GPF, HAF, ISAF, SAF, and the like may be used. From the viewpoint of the strength of the insert 60, the amount of carbon black is preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more, based on 100 parts by mass of the base rubber. From the viewpoint of softness of the insert 60, the amount of carbon black is preferably 50 parts by mass or less, particularly preferably 40 parts by mass or less. Silica may be used together with carbon black or instead of carbon black. Dry silica and wet silica may be used.

The rubber composition includes a softening agent. As preferred softening agents, paraffinic process oils, naphthenic process oils and aromatic process oils are exemplified. From the viewpoint of the softness of the insert 60, the amount of softening agent is preferably 10 parts by mass or more, particularly preferably 20 parts by mass or more, based on 100 parts by mass of the base rubber. From the viewpoint of the strength of the insert 60, the amount of softening agent is preferably 40 parts by mass or less, particularly preferably 30 parts by mass or less.

Stearic acid, zinc oxide, an antioxidant, a wax, a crosslinking aid and the like are added to the rubber composition as needed.

As described above, the insert 60 is soft. By setting the amount of carbon black to be small, the softness of the insert 60 can be achieved. By setting the amount of the softener to a large amount, the softness of the insert 60 can be achieved.

The hardness H2 of the insert 60 measured by a JIS-A type hardness meter is preferably 70 or less. Low stiffness of the side portion 36 can be achieved by the insert 60 having a hardness H2 of 70 or less. From this viewpoint, the hardness H2 is particularly preferably 65 or less. The hardness H2 is preferably 50 or more. The hardness H2 is measured by pressing a JIS-A hardness meter against the cross section shown in Fig. The temperature at the time of measurement is 23 占 폚.

The difference (H1-H2) between the hardness H1 of the clinch portion 58 and the hardness H2 of the insert 60 is 2 or more from the viewpoint of both the softness of the insert 60 and the high rigidity of the clinch portion 58 And particularly preferably 5 or more. The difference (H1-H2) is preferably 25 or less. The hardness H1 is measured by pressing a JIS-A type hardness meter against the cross section shown in Fig. The temperature at the time of measurement is 23 占 폚.

From the viewpoint of low fuel consumption, the loss tangent (tan?) Of the insert 60 is preferably 0.10 or more, and particularly preferably 0.13 or more. The loss tangent is preferably 0.20 or less. The loss tangent is measured in accordance with the provisions of " JIS K 6394 ". The measurement conditions are as follows.

Viscoelastic spectrometer: "VESF-3" by Iwamoto Seisakusho

Initial strain: 10%

Dynamic strain: ± 1%

Frequency: 5 Hz

Deformation Mode: Seal

Measuring temperature: 100 ° C

2, the radially inner side surface 62 of the insert 60 is covered by the clinch portion 58. As shown in Fig. The radially outer side 64 of the insert 60 is covered by the sidewall 56. The insert 60 is not exposed on the surface of the side portion 36. The insert 60 is protected by the clinch portion 58 and the sidewall 56. The inner side surface 62 and the outer side surface 64 may be covered by the clinch portion 58. The inner side surface 62 and the outer side surface 64 may be covered by the side wall 56.

The minimum value of the distance between the surface of the side portion 36 and the insert 60 (indicated by the symbol t in Fig. 1) is preferably 1.0 mm or more. In the tire 16 whose distance is 1.0 mm or more, the insert 60 is not damaged well. From this viewpoint, the distance is more preferably 1.5 mm or more, and particularly preferably 2.0 mm or more. From the viewpoint that the insert 60 can have a sufficient volume, the distance is preferably 5.0 mm or less.

In the tire 16 in which the insert 60 has a sufficient volume, the low rigidity of the side portion 36 is achieved. In this respect, the cross-sectional area of the insert 60 is preferably at least 50 ㎣, particularly preferably at least 70.. The cross sectional area is preferably 200 ㎣ or less. The cross-sectional area is measured in the cross-section shown in Fig.

In Fig. 1, the reference mark BL is indicated. The reference line BL passes through the radially inner end of the core 40 and extends in the axial direction. What is indicated by the symbol Ha is the height of the tire 16 from the reference line and what is indicated by Hb is the height of the insert 60 from the reference line. The ratio of the height Hb to the height Ha is preferably 50% or less, and particularly preferably 45% or less from the viewpoints of fuel economy, steering stability, and ride comfort. The ratio is preferably 20% or more.

The insert 60 having the above-described size exerts its effect on the tire 16 of various sizes. Particularly, in the passenger car tire 16 having a small flatness, the insert 60 exerts its effect. The flatness ratio is preferably 50%, and particularly preferably 40% or less.

In the production of the tire 16, the rubber composition for the sidewall 56, the rubber composition for the clinch portion 58, and the rubber composition for the insert 60 are simultaneously extruded. These rubber compositions are integrated to obtain a rubber sheet. This rubber sheet is assembled with another rubber member to obtain a low cover (unvulcanized tire). This low cover is put into the mold. The outer surface of the row cover contacts the cavity surface of the mold. The inner surface of the row cover contacts the bladder or core. The low cover is pressurized and heated in the mold. The rubber composition of the row cover flows by pressurization and heating. The rubber causes crosslinking reaction by heating to obtain the tire 16. The side portion 36 is formed by the rubber sheet. Instead of extrusion, the side portion 36 may be formed by a strip winding method.

In the present invention, unless otherwise specified, the dimensions and the angles of the respective members of the tire 16 are measured in a state in which air is filled in the tire 16 so that the tire 16 is mounted on the normal rim and has a normal internal pressure do. No load is applied to the tire 16 at the time of measurement. In this specification, the normal rim means the rim defined in the standard based on the tire 16. "Standard Rim" in the JATMA standard, "Design Rim" in the TRA standard, and "Measuring Rim" in the ETRTO standard are regular rims. In the present specification, the normal internal pressure refers to the internal pressure determined in the standard based on the tire 16. "Maximum pressure" in the JATMA standard, "Maximum value" in the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, and "INFLATION PRESSURE" in the ETRTO standard are the normal internal pressure. In the case of a tire for passenger cars, the dimensions and angles are measured in a state where the internal pressure is 180 kPa.

Example

Hereinafter, the effects of the present invention will be apparent from the examples, but the present invention should not be construed as limited on the basis of these examples.

[Example 1]

A tire for a passenger car having the structure shown in Figs. 1 and 2 was produced. The size of this tire is " 245 / 40R18 ". The JIS-A hardness of the side wall of this tire is 58, the hardness H1 of the clinch portion is 75, and the hardness H2 of the insert is 60. The minimum value of the distance t is 2.0 mm. Details of the rubber composition of the clinch portion and the insert are shown in Table 1 below.

caoutchouc

RSS # 3

Polybutadiene

"Nipol 1220" (trade name, manufactured by Nippon Zeon Co., Ltd.), (sheath content: 96.5%)

Carbon black

Product name "Showa Black N220" of Cabot Japan

oil

"Dyna Process Oil AH24" manufactured by Idemitsu Kosan Co., Ltd.

Wax

The product name " Sanok Wax ", trade name "

Antioxidant

N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine

"No crack 6C" product name of Ouchishin Kokagaku Kogyo Co.,

Stearic acid

Niche-like stearic acid

Zinc oxide

Mitsui Kinzuko Boots Co., Ltd. "Akena No. 1"

sulfur

The powder sulfur of Tsurumikagakusa

Vulcanization accelerator

N-tert-butyl-2-benzothiazolylsulfenamide

&Quot; NOUKERA-NS ", trade name of Ouchi-shin Kokagaku Kogyo Co.,

[Examples 4 to 6]

The tires of Examples 4 to 6 were obtained in the same manner as in Example 1 except that the minimum value of the distance t was set as shown in Table 2 below.

[Example 3]

The tires of Example 3 were obtained in the same manner as in Example 1, except that the loss tangent of the insert was changed as shown in Table 2 below by changing the amount of carbon black and the amount of oil.

[Examples 2, 7 and 8 and Comparative Example]

Tires of Examples 2, 6 and 7 and Comparative Examples were obtained in the same manner as in Example 1 except that the hardness H2 of the insert was changed as shown in Table 2 below by changing the amounts of carbon black and oil.

[Driving test]

The tire was mounted on a regular rim, and the tire was filled with air so that the internal pressure was 230 kPa. The tires were mounted on passenger cars with a displacement of 4300 cc. The driver was allowed to drive the passenger car in the racing circuit, and the stability and ride comfort were evaluated. The results are shown in Table 2 below as indices. The larger the value, the better.

[Rolling resistance]

The rolling resistance was measured using a rolling resistance tester under the following measurement conditions.

Used rim: 18 × 8.5-J

Withstand pressure: 200 kPa

Load: 4.6 kN

Speed: 80 km / h

The results are shown in Table 2 below as indices. The smaller the number, the better.

[Durability of beads]

Using a drum tester, the tires were rolled under the following measurement conditions.

Used rim: 18 × 8.5-J

Withstand pressure: 200 kPa

Load: 6.9 kN

Speed: 60 km / h

The time until the beads were damaged was measured. The results are shown in Table 2 below as indices.

As shown in Table 2, the tires of the examples have excellent performance. In this evaluation result, the superiority of the present invention is clear.

The tire according to the present invention can be mounted on various vehicles.

16: pneumatic tire
18: Tread
22: Bead
24: Carcass
26: Support layer
28: Belt
30: Band
36: Side portion
50: Rim Protector
56: sidewall
58:
60: insert

Claims (5)

A pair of beads located radially inwardly of the ends of the tread, a pair of beads extending between one bead and the other bead, and a carcass located radially inward of the tread in the radial direction, And a pair of side portions located on the outside of the carcass in the axial direction,
A pair of wings positioned between the tread and the side portion,
Each of the side portions has a rim protector protruding in a tapered manner toward the axially outward side,
Wherein the side portion includes an insert made of rubber in the vicinity of the rim protector,
Wherein the cross-sectional shape of the insert is a triangular shape tapering toward the axially outer side,
The side portion having a sidewall extending radially inwardly from an end of the tread and a clinch portion extending radially inwardly at a radially inner end of the sidewall,
The insert is surrounded by a carcass, a sidewall and a clinch portion,
Wherein the radially inner side of the insert is covered by a clinch portion, the radially outer side of the insert is covered by a sidewall,
Wherein the JIS-A hardness H2 of the insert is smaller than the JIS-A hardness H1 of the clinch portion. delete delete The pneumatic tire according to claim 1, wherein the difference (H1-H2) between the hardness H1 of the clinch portion and the hardness H2 of the insert is 2 or more. The pneumatic tire according to claim 1 or 4, wherein the minimum value of the distance between the surface of the side portion and the insert is 1.0 mm or more.

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