pneumatic tires
The pneumatic tire design optimizes airflow and drainage through specific angles and grooves, addressing air resistance and wet performance challenges to achieve low fuel consumption and improved wet handling.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- SUMITOMO RUBBER INDUSTRIES LTD
- Filing Date
- 2024-12-26
- Publication Date
- 2026-07-08
Smart Images
Figure 2026114783000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to pneumatic tires.
Background Art
[0002] Conventionally, various pneumatic tires having specific profiles have been proposed. For example, Patent Document 1 below proposes a pneumatic tire that can achieve both noise performance and low fuel consumption performance by including a profile with a single radius of curvature from the maximum width position of the tire to the outer end position.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] However, the resistance related to low fuel consumption performance includes, in addition to the rolling resistance improved by the pneumatic tire of Patent Document 1, the air resistance during running. Further improvement has been expected for the air resistance during running even in the pneumatic tire of Patent Document 1. In addition, the profile for improving rolling resistance tends to reduce wet performance, and there has also been a demand for improvement in wet performance.
[0005] The present invention has been devised in view of the above actual situation, and the main object thereof is to provide a pneumatic tire that can achieve both low fuel consumption performance and wet performance.
Means for Solving the Problems
[0006] The present invention relates to a pneumatic tire with a specified direction of rotation, having a profile defined on the outer surface of the tire meridian cross section in a normal state, which is an unloaded state in which the tire is mounted on a normal rim and adjusted to a normal internal pressure, wherein the profile includes a contact surface of a tread portion extending from a first contact end to a second contact end, and a first side outer surface of a sidewall portion extending inward in the tire radial direction from the first contact end, wherein the first side outer surface has a first position defined at a distance of 15% of the tire cross section height inward in the tire radial direction from the tire equator of the contact surface, the tread portion has a first shoulder circumferential groove extending furthest towards the first contact end in the tire circumferential direction between the tire equator and the first contact end, and a first shoulder land portion separated by the first shoulder circumferential groove and the first contact end, wherein the contact surface has a first virtual line, which is a tangent at an intermediate position in the tire axial direction of the first shoulder land portion, which is inclined inward in the tire radial direction toward the outward direction in the tire axial direction, and the first virtual line is 74-80 with respect to the tire radial direction The first side outer surface has a first angle of 36°, the second imaginary line which is the tangent at the first position is inclined in the same direction as the first imaginary line with respect to the tire radial direction, the second imaginary line has a second angle of 36-40° with respect to the tire radial direction, the contact surface has a contact width TW (mm) which is the distance in the tire axial direction between the first contact end and the second contact end, the first contact end is located at a distance t inward in the tire radial direction from the tire equator, and the first shoulder land portion is circumferential to the first shoulder The tire has a first shoulder lateral groove extending in a direction inclined with respect to the tire axis from the forward groove to the first contact end, the first shoulder lateral groove has a third angle θ3 which is the angle on the first side in the rotational direction with respect to the first shoulder circumferential groove, and a fourth angle θ4 which is the angle on the first side in the rotational direction with respect to the first contact end, and the third angle θ3 (°), the fourth angle θ4 (°), the distance t (mm) between the first contact end and the tire equator, and the contact width TW (mm) satisfy the following formula 1, the tire is pneumatic.
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[0007] The pneumatic tire of the present invention, by having the above-described configuration, can achieve both low fuel consumption and wet performance. [Brief explanation of the drawing]
[0008] [Figure 1] This is a cross-sectional view showing one embodiment of the profile of the pneumatic tire of the present invention. [Figure 2] This is an enlarged view of section A in Figure 1. [Figure 3] This is a diagram showing the tread section. [Figure 4] This is a schematic diagram of a mold for forming pneumatic tires. [Modes for carrying out the invention]
[0009] One embodiment of the present invention will be described in detail below with reference to the drawings. Figure 1 is a meridian cross-sectional view of the pneumatic tire 1 of this embodiment, showing the profile 2 in its normal state. Here, "normal state" refers to the unloaded state in which the pneumatic tire 1 is mounted on a normal rim R and adjusted to the normal internal pressure. Unless otherwise specified, the dimensions of each part of the pneumatic tire 1 are values measured in this normal state.
[0010] "Regular Rim R" refers to the rim specified for each tire by a standard system that includes the standard on which the pneumatic tire 1 is based. For example, it is a "Standard Rim" for JATMA, a "Design Rim" for TRA, and a "Measuring Rim" for ETRTO. If there is no standard system that includes the standard on which the pneumatic tire 1 is based, "Regular Rim R" refers to the rim with the smallest rim diameter and the smallest rim width among rims that can be mounted on and do not cause air leaks.
[0011] "Regular internal pressure" refers to the air pressure specified for each tire by each standard, if there is a standard system on which the pneumatic tire 1 is based. For example, it is the "maximum air pressure" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and the "INFLATION PRESSURE" for ETRTO. If there is no standard system on which the pneumatic tire 1 is based, "regular internal pressure" refers to the air pressure specified for each tire by the manufacturer, etc.
[0012] As shown in Figure 1, the pneumatic tire 1 is suitably used, for example, as a passenger car tire. The pneumatic tire 1 of this embodiment has a profile 2 defined by the outer surface in the tire meridian cross-section in a normal state. The profile 2 of this embodiment includes the contact surface 3a of the tread portion 3 extending from the first contact end Te1 to the second contact end Te2.
[0013] The contact surface 3a has, for example, a tire equator C which is the midpoint in the tire axial direction between the first contact end Te1 and the second contact end Te2, and a contact width TW which is the distance in the tire axial direction between the first contact end Te1 and the second contact end Te2. Preferably, the first contact end Te1 is located at a distance t inward in the tire radial direction from the tire equator C.
[0014] Here, "first contact point Te1" and "second contact point Te2" are the outermost contact points in the tire axial direction when a pneumatic tire 1 in a normal state is loaded with 70% of its normal load and makes contact with a plane at a camber angle of 0°.
[0015] When there is a standard system including the standards on which the pneumatic tire 1 is based, the "normal load" is the load defined for each tire by each standard. In the case of JATMA, it is the "maximum load capacity"; in the case of TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and in the case of ETRTO, it is the "LOAD CAPACITY". When there is no standard system including the standards on which the pneumatic tire 1 is based, the "normal load" is the load determined for each tire by the manufacturer or the like as the maximum applicable load when using the pneumatic tire 1.
[0016] The tread portion 3 of the present embodiment has a plurality of circumferential grooves 4 extending in the tire circumferential direction and a plurality of land portions 5 divided by the plurality of circumferential grooves 4. The plurality of circumferential grooves 4 may, for example, extend linearly in the tire circumferential direction, may extend in a zigzag shape, or may be mixed with those extending linearly and those extending in a zigzag shape. Such a tread portion 3 helps to achieve both the rigidity and the drainage performance of the land portion 5.
[0017] The plurality of circumferential grooves 4 of the present embodiment includes a first shoulder circumferential groove 4A that extends in the tire circumferential direction on the side closest to the first grounding end Te1 between the tire equator C and the first grounding end Te1. The plurality of land portions 5 of the present embodiment includes a first shoulder land portion 5A divided by the first shoulder circumferential groove 4A and the first grounding end Te1.
[0018] It is desirable that a first virtual line L1, which is a tangent line at the intermediate position Pm in the tire axial direction of the first shoulder land portion 5A, inclines inward in the tire radial direction toward the outside in the tire axial direction. Such a ground contact surface 3a helps to smooth the flow of air during running from the tread portion 3 to the sidewall portion 6 described later and suppress the separation of air.
[0019] Here, the intermediate position Pm of the first shoulder land portion 5A is a position that is separated by a distance W1 / 2, which is half of the maximum width W1 in the tire axial direction of the first shoulder land portion 5A, inward in the tire axial direction from the first grounding end Te1.
[0020] Figure 2 is an enlarged view of part A in Figure 1. As shown in Figure 2, the first virtual line L1 of this embodiment is inclined at a first angle θ1 with respect to the tire radial direction. The first angle θ1 is preferably 74° or more. By having the first angle θ1 of 74° or more, excessive deformation during grounding can be suppressed and the rolling resistance can be reduced. From such a viewpoint, the first angle θ1 is more preferably 76° or more, and even more preferably 77° or more.
[0021] The first angle θ1 is preferably 80° or less. By having the first angle θ1 of 80° or less, the flow of air during running from the tread portion 3 to the sidewall portion 6 described later becomes smooth, the separation of air is suppressed, and the air resistance during running can be reduced. From such a viewpoint, the first angle θ1 is more preferably 78° or less, and even more preferably 77° or less.
[0022] From these, the first angle θ1 is preferably 74 to 80°, more preferably 76 to 78°, and even more preferably 77°. Note that the combination of the upper limit value and the lower limit value of these numerical ranges can be arbitrarily selected.
[0023] As shown in Figure 1, the profile 2 of this embodiment includes the first side outer surface 6a of the sidewall portion 6 extending from the first grounding end Te1 to the inside in the tire radial direction, and the first bead outer surface 7a of the bead portion 7 located inside the first side outer surface 6a in the tire radial direction.
[0024] On the first side outer surface 6a of this embodiment, a first position P1 is defined at a distance D1 of 15% of the tire section height SH from the tire equator C of the ground contact surface 3a to the inside in the tire radial direction. It is desirable that the second virtual line L2, which is a tangent line at the first position P1, of the first side outer surface 6a is inclined in the same direction as the first virtual line L1 with respect to the tire radial direction. Such a first side outer surface 6a helps to smooth the flow of air during running from the tread portion 3 to the sidewall portion 6 and suppress the separation of air.
[0025] As shown in Figure 2, the second dashed line L2 in this embodiment is inclined at a second angle θ2 with respect to the tire radial direction. The second angle θ2 is preferably 36° or more. When the second angle θ2 is 36° or more, the airflow from the tread portion 3 to the sidewall portion 6 during driving becomes smoother, suppressing air separation and reducing air resistance during driving. From this viewpoint, the second angle θ2 is more preferably 37° or more, and even more preferably 38° or more.
[0026] The second angle θ2 is preferably 40° or less. By having the second angle θ2 be 40° or less, air separation on the outer side of the sidewall portion 6 in the tire radial direction can be suppressed, thereby reducing air resistance during driving. From this viewpoint, the second angle θ2 is more preferably 39° or less, and even more preferably 38° or less.
[0027] Based on these considerations, the second angle θ2 is preferably 36 to 40°, more preferably 37 to 39°, and even more preferably 38°. The combination of the upper and lower limits within these numerical ranges can be arbitrarily selected.
[0028] Figure 3 is an unfolded view of the tread portion 3. As shown in Figure 3, the pneumatic tire 1 of this embodiment has a tread portion 3 with a specified rotation direction Rd. The first shoulder land portion 5A of this embodiment has a first shoulder lateral groove 8 that extends from the first shoulder circumferential groove 4A to the first contact end Te1 in a direction inclined with respect to the tire axis. Such a first shoulder lateral groove 8 can smoothly discharge air and water from the first shoulder circumferential groove 4A from the first contact end Te1, thereby reducing air resistance during driving and improving drainage.
[0029] The first shoulder lateral groove 8 of this embodiment has a third angle θ3, which is the angle on the first side of the rotational direction Rd relative to the first shoulder circumferential groove 4A, and a fourth angle θ4, which is the angle on the first side of the rotational direction Rd relative to the first grounding end Te1. The first shoulder lateral groove 8 has a curved shape, for example, having the third angle θ3 and the fourth angle θ4. The first shoulder lateral groove 8 is not limited to this embodiment, and may, for example, extend in a straight line or be bent.
[0030] As shown in Figures 1 and 3, it is desirable that the third angle θ3 (°), the fourth angle θ4 (°), the distance t (mm) between the first contact end Te1 and the tire equator C, and the contact width TW (mm) satisfy the following equation 1.
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[0031] Such a pneumatic tire 1 can reduce air resistance during driving while maintaining good rolling resistance, and also has excellent drainage capabilities. Therefore, the pneumatic tire 1 of this embodiment can achieve both low fuel consumption and good wet performance.
[0032] In a more preferred embodiment, the third angle θ3 is an obtuse angle of 91° or more. A third angle θ3 of 91° or more allows air and water in the first shoulder circumferential groove 4A to be smoothly discharged from the first ground-contact end Te1. From this viewpoint, the third angle θ3 is more preferably 120° or more, and even more preferably 130° or more.
[0033] The third angle θ3 is preferably 170° or less. By having the third angle θ3 be 170° or less, the rigidity of the first shoulder land portion 5A can be maintained and the steering stability performance of the pneumatic tire 1 can be improved. From this viewpoint, the third angle θ3 is more preferably 165° or less, and even more preferably 160° or less.
[0034] Based on these considerations, the third angle θ3 is preferably 91 to 170°, more preferably 120 to 165°, and even more preferably 130 to 160°. The combination of the upper and lower limits within these numerical ranges can be arbitrarily selected.
[0035] The fourth angle θ4 is preferably 10° or more. Having the fourth angle θ4 at 10° or more maintains the rigidity of the first shoulder land portion 5A and improves the steering stability of the pneumatic tire 1. From this viewpoint, the fourth angle θ4 is more preferably 15° or more, and even more preferably 20° or more.
[0036] The fourth angle θ4 is preferably an acute angle of 89° or less. Having a fourth angle θ4 of 89° or less allows air and water in the first shoulder circumferential groove 4A to be smoothly discharged from the first ground-contact end Te1. From this viewpoint, the fourth angle θ4 is more preferably 60° or less, and even more preferably 50° or less.
[0037] Based on these considerations, the fourth angle θ4 is preferably 10 to 89°, more preferably 15 to 60°, and even more preferably 20 to 50°. The combination of the upper and lower limits within these numerical ranges can be arbitrarily selected.
[0038] The first shoulder land portion 5A preferably has a first shoulder sipe 9 that extends from the first shoulder circumferential groove 4A toward the first contact end Te1 and terminates within the first shoulder land portion 5A. The first shoulder sipe 9 extends, for example, parallel to the first shoulder transverse groove 8. The first shoulder sipe 9 has chamfered edges formed on at least one, for example, both, outer edges in the radial direction of the tire.
[0039] Such a first shoulder sipe 9, in cooperation with the first shoulder lateral groove 8, can achieve both drainage and rigidity of the first shoulder land portion 5A. Hereinafter, in this specification, a "sipe" is a cut with a width of less than 2 mm perpendicular to the longitudinal direction of the portion excluding the chamfered portion, and is distinguished from a lateral groove with a groove width of 2 mm or more.
[0040] The multiple circumferential grooves 4 preferably include a second shoulder circumferential groove 4B that extends furthest towards the second contact end Te2 between the tire equator C and the second contact end Te2. The multiple circumferential grooves 4 are not limited to two, but may be three or more, for example.
[0041] The multiple land sections 5 include, for example, a second shoulder land section 5B separated by a second shoulder circumferential groove 4B and a second contact end Te2, and a crown land section 5C separated by a first shoulder circumferential groove 4A and a second shoulder circumferential groove 4B. Such land sections 5 have excellent rigidity and help improve the handling stability of the pneumatic tire 1.
[0042] The second shoulder land portion 5B of this embodiment has a second shoulder lateral groove 10 that extends from the second contact end Te2 toward the second shoulder circumferential groove 4B and terminates within the second shoulder land portion 5B. The second shoulder lateral groove 10 is inclined, for example, in the same direction as the first shoulder lateral groove 8 with respect to the tire axis. Such a second shoulder lateral groove 10 can achieve both drainage and rigidity of the second shoulder land portion 5B.
[0043] The second shoulder land portion 5B has, for example, a second shoulder sipe 11 that extends from the second shoulder circumferential groove 4B to the second contact end Te2. The second shoulder sipe 11 extends, for example, parallel to the second shoulder lateral groove 10. The second shoulder sipe 11 has chamfered edges formed on at least one, for example, both edges, on the outer side in the radial direction of the tire. Such a second shoulder sipe 11 can work in cooperation with the second shoulder lateral groove 10 to achieve both drainage and rigidity of the second shoulder land portion 5B.
[0044] The crown sipe 5C includes, for example, a first crown sipe 12 extending from the first shoulder circumferential groove 4A to the second shoulder circumferential groove 4B, and a second crown sipe 13 and a third crown sipe 14 terminating within the crown sipe 5C. The first crown sipe 12 has a chamfer formed on at least one, for example, both edges on the outer side in the radial direction of the tire. The second crown sipe 13 and the third crown sipe 14 in this embodiment do not have a chamfer formed. In such a crown sipe 5C, each sipe works in cooperation to achieve both drainage and rigidity.
[0045] The second crown sipe 13 extends, for example, from the first shoulder circumferential groove 4A toward the second shoulder circumferential groove 4B. The third crown sipe 14 extends, for example, from the second shoulder circumferential groove 4B toward the first shoulder circumferential groove 4A. It is desirable that the second crown sipe 13 and the third crown sipe 14 each terminate beyond the tire equator C. Such second crown sipes 13 and third crown sipes 14 help to balance drainage and the rigidity of the crown land portion 5C.
[0046] As shown in Figure 1, the radial distance t between the first contact point Te1 and the tire equator C is preferably 2% or more of the contact width TW. When the distance t is 2% or more of the contact width TW, the airflow from the tread portion 3 to the sidewall portion 6 during driving becomes smoother, suppressing air separation and reducing air resistance during driving. From this viewpoint, the distance t between the first contact point Te1 and the tire equator C is more preferably 3% or more of the contact width TW.
[0047] The distance t between the first contact point Te1 and the tire equator C is preferably 6% or less of the contact width TW. Having a distance D2 of 6% or less of the contact width TW suppresses excessive deformation during contact and reduces rolling resistance. From this viewpoint, the distance t between the first contact point Te1 and the tire equator C is more preferably 5% or less of the contact width TW.
[0048] Based on these considerations, the distance t between the first contact end Te1 and the tire equator C is preferably 2% to 6% of the contact width TW, and more preferably 3% to 5%. The combination of the upper and lower limits within these numerical ranges can be arbitrarily selected.
[0049] The maximum width W1 of the first shoulder land portion 5A in the axial direction of the tire is preferably 20% or more of the contact width TW. By having a maximum width W1 of the first shoulder land portion 5A of 20% or more of the contact width TW, air that has been swept around by the vehicle's influence during driving can be smoothly directed into the first shoulder circumferential groove 4A, thereby reducing air resistance during driving. Furthermore, by positioning the first shoulder circumferential groove 4A at a location with high ground pressure, it also helps to increase the driving speed at which hydroplaning occurs. From this viewpoint, the maximum width W1 of the first shoulder land portion 5A is more preferably 22% or more of the contact width TW.
[0050] The maximum width W1 of the first shoulder land portion 5A in the tire axial direction is preferably 30% or less of the contact width TW. By having the maximum width W1 of the first shoulder land portion 5A be 30% or less of the contact width TW, it is possible to suppress the rigidity of the first shoulder land portion 5A from becoming excessively high, thereby improving the handling stability performance of the pneumatic tire 1 and also helping to improve the drainage performance on the outer side in the tire axial direction. From this viewpoint, the maximum width W1 of the first shoulder land portion 5A is more preferably 28% or less of the contact width TW.
[0051] Based on these considerations, the maximum width W1 in the tire axial direction of the first shoulder land portion 5A is preferably 20% to 30% of the contact width TW, and more preferably 22% to 28%. The combination of the upper and lower limits within these numerical ranges can be arbitrarily selected.
[0052] The pneumatic tire 1 of this embodiment does not have a rim guard on the sidewall portion 6. Since such a pneumatic tire 1 does not have a rim guard, which has a significant impact on air resistance, it can reduce air resistance during driving.
[0053] A standard rim R has, for example, a first rim end R1 which is the end on the first grounding end Te1 side, a second rim end R2 which is the end on the second grounding end Te2 side, and a maximum width RW which is the distance in the rim width direction between the first rim end R1 and the second rim end R2.
[0054] The pneumatic tire 1 should preferably have a tire section width SW that is 6 mm or more larger than the maximum width RW in the rim width direction of the regular rim R. Such a pneumatic tire 1 can prevent the regular rim R from contacting curbs, etc., even without a rim guard, and can achieve both durability and fuel efficiency. Here, the tire section width SW is the maximum width in profile 2 and does not include localized protrusions or rim guards.
[0055] The radial distance d between the first rim edge R1 and the first bead outer surface 7a is preferably 3 mm or less. Such a first bead outer surface 7a suppresses the generation of turbulence between the first rim edge R1 and the first bead outer surface 7a, and by maintaining the kinetic energy of the air, it is possible to reduce air resistance during driving.
[0056] It is desirable that the first side outer surface 6a has a second position P2 located at a distance D2 of 25% of the tire cross-sectional height SH, inward from the tire equator C in the tire radial direction, and a third position P3 located at a distance D3 of 19 mm inward from the tire equator C in the tire radial direction. In this embodiment, the first side outer surface 6a has a fourth position P4 located inward in the tire radial direction from the virtual intersection Pv of the first virtual line L1 and the second virtual line L2.
[0057] As shown in Figure 2, it is desirable that the tire radial distance D4 between the first position P1 and the second position P2 is equal to the tire radial distance D4 between the first position P1 and the fourth position P4. In this case, the first position P1 is an intermediate position in the tire radial direction between the second position P2 and the fourth position P4. Such a first position P1 is suitable as a representative point of the outer region of the first side outer surface 6a in the tire radial direction.
[0058] Figure 4 is a schematic diagram of a mold M for forming a pneumatic tire 1. As shown in Figures 1 to 4, the mold M of this embodiment includes a tread mold M1 for forming the tread portion 3 and a side mold M2 for forming the sidewall portion 6. The pneumatic tire 1 has, for example, a mold divider line ML between the tread mold M1 and the side mold M2.
[0059] As shown in Figure 2, the mold splitting line ML preferably includes a stepped portion 15 having a height h of 0.4 mm or less. Such a stepped portion 15 can suppress the occurrence of cracks originating from the mold splitting line ML and improve the durability of the pneumatic tire 1.
[0060] Furthermore, by keeping the height h of the stepped portion 15 to 0.4 mm or less, the increase in air resistance during driving can be suppressed, improving the fuel efficiency of the pneumatic tire 1. Here, the height h of the stepped portion 15 is the maximum height of the stepped portion 15 protruding from the first side outer surfaces 6a on both sides in the tire radial direction in a direction perpendicular to the first side outer surfaces 6a.
[0061] The stepped portion 15 of the mold division line ML is preferably located between the second position P2 and the third position P3. By positioning the stepped portion 15 further outward in the tire radial direction than the second position P2, the decrease in airflow velocity near the maximum width position of the first side outer surface 6a can be suppressed, thereby reducing air resistance during driving.
[0062] Since the stepped portion 15 is located inward in the tire radial direction from the third position P3, the reduction in airflow velocity near the buttress on the outer side of the first side outer surface 6a in the tire radial direction can be suppressed, thereby reducing air resistance during driving.
[0063] As shown in Figure 1, the pneumatic tire 1 of this embodiment has a specified orientation for mounting on the vehicle in the tire axial direction. The first contact end Te1 of this embodiment is located on the outside of the vehicle when mounted on the vehicle. The second contact end Te2 is preferably located on the inside of the vehicle when mounted on the vehicle. Such a pneumatic tire 1 can define the profile 2 on the outside of the vehicle, which has a large impact on air resistance, as a shape that reduces air resistance, thereby improving fuel efficiency.
[0064] Profile 2 of this embodiment includes a second side outer surface 6b of the sidewall portion 6 extending inward in the tire radial direction from the second contact end Te2, and a second bead outer surface 7b of the bead portion 7 located inward in the tire radial direction of the second side outer surface 6b.
[0065] Profile 2 may be formed symmetrically in the tire axial direction, for example, with respect to the tire equator C. In this case, the contact surface 3a of the second shoulder land portion 5B, the second side outer surface 6b, and the second bead outer surface 7b are symmetrical to the contact surface 3a of the first shoulder land portion 5A, the first side outer surface 6a, and the first bead outer surface 7a, respectively. Such a pneumatic tire 1 can reduce air resistance when driving inside the vehicle, thereby further improving fuel efficiency.
[0066] Although particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above and can be implemented in various modified forms.
[0067] [Note] The present invention is as follows:
[0068] [Invention 1] A pneumatic tire with a specified direction of rotation, The tire has a profile defined by the outer surface in the meridional cross-section of a tire in a normal state, which is a tire mounted on a normal rim and adjusted to the normal internal pressure in an unloaded state. The profile includes a contact surface of the tread portion extending from a first contact end to a second contact end, and a first side outer surface of the sidewall portion extending inward in the tire radial direction from the first contact end. On the outer surface of the first side, a first position is defined at a distance of 15% of the tire cross-sectional height, located radially inward from the tire equator of the contact surface. The tread portion has a first shoulder circumferential groove that extends furthest towards the first contact end in the tire circumferential direction between the tire equator and the first contact end, and a first shoulder land portion that is separated by the first shoulder circumferential groove and the first contact end. The aforementioned contact surface has a first imaginary line, which is a tangent at the midpoint of the tire axial direction of the first shoulder land portion, that is inclined outward in the tire axial direction and inward in the tire radial direction. The first dashed line has a first angle of 74-80° with respect to the tire radial direction, The first outer side surface is such that the second imaginary line, which is tangent at the first position, is inclined in the same direction as the first imaginary line with respect to the tire radial direction. The second dashed line has a second angle of 36-40° with respect to the tire radial direction. The aforementioned contact surface has a contact width TW (mm), which is the distance in the tire axial direction between the first contact end and the second contact end. The first contact end is located at a distance t inward in the tire radial direction from the tire equator. The first shoulder land portion has a first shoulder transverse groove that extends in a direction inclined with respect to the tire axis from the first shoulder circumferential groove to the first contact end, The first shoulder lateral groove has a third angle θ3 which is the angle on the first side in the rotational direction relative to the first shoulder circumferential groove, and a fourth angle θ4 which is the angle on the first side in the rotational direction relative to the first ground contact end. The third angle θ3(°), the fourth angle θ4(°), the distance t(mm) between the first contact end and the tire equator, and the contact width TW(mm) satisfy the following equation 1: Pneumatic tires.
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[0069] [Invention 2] The pneumatic tire according to the present invention 1, wherein the third angle θ3 is 91 to 170°.
[0070] [Invention 3] The pneumatic tire according to invention 1 or 2, wherein the fourth angle θ4 is 10 to 89°.
[0071] [4th Invention] The pneumatic tire according to any one of inventions 1 to 3, wherein the distance t (mm) between the first contact end and the tire equator is 2% to 6% of the contact width TW (mm).
[0072] [5th Invention] A pneumatic tire according to any one of invention 1 to 4, having a tire cross-sectional width that is 6 mm or more greater than the maximum width in the rim width direction of the standard rim.
[0073] [Invention 6] The profile includes the first bead outer surface of the bead portion located radially inward of the first side outer surface of the tire, The pneumatic tire according to any one of inventions 1 to 5, wherein the distance in the tire radial direction between the first rim end, which is the end of the regular rim on the first contact end side, and the outer surface of the first bead is 3 mm or less.
[0074] [7th Invention] The mold has a split line between the tread mold for forming the tread portion and the side mold for forming the sidewall portion. The mold cut line includes a stepped portion having a height of 0.4 mm or less, as described in any one of invention 1 to 6.
[0075] [8th Invention] On the outer surface of the first side, a second position is defined at a distance of 25% of the tire cross-sectional height, located radially inward from the tire equator, and a third position is defined at a distance of 19 mm, located radially inward from the tire equator. The stepped portion is located between the second position and the third position, in the pneumatic tire according to the present invention, as described in 7.
[0076] [Invention 9] On the outer surface of the first side, a fourth position is defined which is located inside the tire radial direction of the virtual intersection of the first virtual line and the second virtual line. The pneumatic tire according to the present invention, wherein the first position is an intermediate position in the tire radial direction between the second position and the fourth position.
[0077] [Invention 10] The orientation in which it is installed on the vehicle is specified. The first contact end is located on the outside of the vehicle when mounted on the vehicle, as described in any one of invention 1 to 9. [Explanation of symbols]
[0078] 1. Pneumatic tire 2 Profiles 3. Tread section 3a Ground plane 4A First shoulder circumferential groove 5A 1st Shoulder Track and Field Club 6a First side outer surface 8. First shoulder lateral groove
Claims
1. A pneumatic tire with a specified direction of rotation, The tire has a profile defined by the outer surface in the meridional cross-section of a tire in a normal state, which is a tire mounted on a normal rim and adjusted to the normal internal pressure in an unloaded state. The profile includes a contact surface of the tread portion extending from a first contact end to a second contact end, and a first side outer surface of the sidewall portion extending inward in the tire radial direction from the first contact end. On the outer surface of the first side, a first position is defined at a distance of 15% of the tire cross-sectional height, located radially inward from the tire equator of the contact surface. The tread portion has a first shoulder circumferential groove that extends furthest towards the first contact end in the tire circumferential direction between the tire equator and the first contact end, and a first shoulder land portion that is separated by the first shoulder circumferential groove and the first contact end. The aforementioned contact surface has a first imaginary line, which is a tangent at the midpoint of the tire axial direction of the first shoulder land portion, that is inclined outward in the tire axial direction and inward in the tire radial direction. The first dashed line has a first angle of 74 to 80° with respect to the tire radial direction, The first side outer surface is such that the second imaginary line, which is tangent at the first position, is inclined in the same direction as the first imaginary line with respect to the tire radial direction. The second dashed line has a second angle of 36 to 40° with respect to the tire radius direction. The aforementioned contact surface has a contact width TW (mm), which is the distance in the tire axial direction between the first contact end and the second contact end. The first contact end is located at a distance t inward in the tire radial direction from the tire equator. The first shoulder land portion has a first shoulder transverse groove that extends in a direction inclined with respect to the tire axis from the first shoulder circumferential groove to the first contact end, The first shoulder lateral groove has a third angle θ3 which is the angle on the first side in the rotational direction relative to the first shoulder circumferential groove, and a fourth angle θ4 which is the angle on the first side in the rotational direction relative to the first ground contact end. The third angle θ3 (°), the fourth angle θ4 (°), the distance t (mm) between the first contact end and the tire equator, and the contact width TW (mm) satisfy the following formula 1: Pneumatic tires. [Math 1]
2. The pneumatic tire according to claim 1, wherein the third angle θ3 is 91 to 170°.
3. The pneumatic tire according to claim 2, wherein the fourth angle θ4 is 10 to 89°.
4. The pneumatic tire according to any one of claims 1 to 3, wherein the distance t (mm) between the first contact end and the tire equator is 2% to 6% of the contact width TW (mm).
5. A pneumatic tire according to any one of claims 1 to 3, having a tire cross-sectional width that is 6 mm or more greater than the maximum width in the rim width direction of the standard rim.
6. The profile includes the first bead outer surface of the bead portion located on the inner side of the first side outer surface in the radial direction of the tire, The pneumatic tire according to any one of claims 1 to 3, wherein the distance in the radial direction between the first rim end, which is the end of the regular rim on the first contact end side, and the outer surface of the first bead is 3 mm or less.
7. The mold has a split line between the tread mold for forming the tread portion and the side mold for forming the sidewall portion. The pneumatic tire according to any one of claims 1 to 3, wherein the mold cut line includes a stepped portion having a height of 0.4 mm or less.
8. On the outer surface of the first side, a second position is defined at a distance of 25% of the tire cross-sectional height, located radially inward from the tire equator, and a third position is defined at a distance of 19 mm radially inward from the tire equator. The pneumatic tire according to claim 7, wherein the stepped portion is located between the second position and the third position.
9. On the outer surface of the first side, a fourth position is defined which is located inside the tire radial direction of the virtual intersection of the first virtual line and the second virtual line. The pneumatic tire according to claim 8, wherein the first position is an intermediate position in the tire radial direction between the second position and the fourth position.
10. The orientation in which it is installed on the vehicle is specified. The first ground contact end is located on the outside of the vehicle when mounted on the vehicle, as described in any one of claims 1 to 3.