Pneumatic tire for heavy load

Abstract

To provide a pneumatic tire 2 for a heavy load which can improve uneven wear resistance.SOLUTION: A tire 2 has a call with a flat ratio of 65% or less. The tire 2 includes a tread 4, and a reinforcement layer 20. The reinforcement layer 20 includes a belt 38 and a band 40. The belt 38 includes a plurality of belt plies 42 which is aligned in a radial direction. The band 40 includes a full band 48 having both ends 48e opposite to each other while sandwiching an equatorial plane, and a pair of edge bands 50 which is positioned in outside of an end 48e of the full band 48 in a radial direction. The full band 48 is composed of two end regions 48B, and a central region 48B sandwiched between the two end regions 48B. Density of a band cord in the central region 48B is lower than density of a band cord of an end region 48B. In an axial direction, an end 48e of the full band 48 and an inner end 50ue of an edge band 50 are positioned in outside of a shoulder circumferential groove 28s configured in the tread 4.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a heavy duty pneumatic tire. [Background technology]

[0002] At least two circumferential grooves are formed in the tread of a heavy-duty pneumatic tire (hereinafter referred to as tire) from the viewpoint of drainage performance. Of the circumferential grooves formed in the tread, the one located on the outer side in the axial direction is the shoulder circumferential groove. In this tire, the dimensional change is large in the shoulder portion of the tread including the shoulder circumferential groove during running. In particular, in the case of a low aspect ratio tire having an aspect ratio of 65% or less, the dimensional change is likely to occur in the shoulder portion during running. Tires in which the shoulder portions of the tread are prone to dimensional change are prone to uneven wear.

[0003] Patent Document 1 discloses a tire having, as a reinforcing layer, a belt including a large number of parallel belt cords and a band including a spirally wound band cord, and further, the band has a full band and an edge band. It is believed that a tire having a reinforcing layer of this configuration can suppress dimensional changes in the shoulder portion during running. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-47999 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been an increasing demand for LRR (low rolling resistance) tires, and there are an increasing number of cases where tire tread patterns with increased rigidity, especially in the center area of ​​the tread, are required. On the other hand, in the tire of Patent Document 1 in which the shape change in the vicinity of the shoulder circumferential groove is suppressed, if a pattern with a high rigidity in the center part of the tread is further adopted, the degree of dimensional change (change in outer diameter) can be reduced, but the dimensional change in the center part of the tread is excessively suppressed. In this case, too, the shoulder part of the tread is more susceptible to dimensional change than the center part of the tread. Therefore, the tire of Patent Document 1 in which a pattern with a high rigidity in the center part of the tread is further adopted may have poor uniformity of ground contact pressure on the tread surface and poor resistance to uneven wear.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a heavy-duty pneumatic tire in which the degree of dimensional change in the tread is small and the difference between the dimensional change in the center portion of the tread and the dimensional change in the shoulder portion of the tread is small. [Means for solving the problem]

[0007] (1) A heavy-duty pneumatic tire according to one aspect of the present invention comprises: The tire has a nominal aspect ratio of 65% or less and is provided with a tread that comes into contact with a road surface, and a reinforcing layer that is located radially inside the tread, At least two circumferential grooves are cut into the tread to form at least three land portions arranged in parallel in the axial direction, a circumferential groove located on an outer side in the axial direction of the at least two circumferential grooves is a shoulder circumferential groove, a land portion located on an outer side of the shoulder circumferential groove in the axial direction is a shoulder land portion, and one of the at least three land portions is a land portion including the equator of the tire, The reinforcing layer includes a belt including a number of parallel belt cords and a band including a spirally wound band cord, The belt includes a plurality of belt plies arranged in a radial direction, The band includes a full band having both ends facing each other across an equator plane, and a pair of edge bands located radially outward of the ends of the full band, The full band includes two end regions located axially outward and a central region sandwiched between the two end regions, and the density of the band cord in the central region is lower than the density of the band cord in the end regions, an end of the full band is located outside the shoulder circumferential groove in the axial direction, In the axial direction, an inner end of the edge band is located outside the shoulder circumferential groove.

[0008] This tire is a low-profile pneumatic tire for heavy loads, with the center portion of the tread having high rigidity. This tire has a reinforcing layer that has a full band having opposite ends on either side of the equatorial plane, and a pair of edge bands that are positioned radially outboard of the ends of the full band, thereby suppressing dimensional changes in the tread. Furthermore, since the density of the full band band cord is lower in the central region than in the end regions, the difference in dimensional change between the center portion of the tread, which is relatively less susceptible to dimensional change, and the shoulder portions of the tread, which are relatively more susceptible to dimensional change, is small. Therefore, this tire has good resistance to uneven wear, even though it has a low profile and the rigidity of the central portion of the tread is high.

[0009] (2) In the heavy-duty pneumatic tire of (1) above, the width of the central region is preferably 20% or more of the width of the tread surface, In the axial direction, an end of the central region is located inside the shoulder circumferential groove.

[0010] (3) In the heavy-duty pneumatic tire of (1) or (2) above, the density of the band cord in the end region is preferably 1.2 to 2.0 times the density of the band cord in the central region.

[0011] (4) In the heavy-duty pneumatic tire described in any one of (1) to (3) above, the distance from the tire equator to the shoulder circumferential groove is preferably 45% or more and 70% or less of the distance from the tire equator to an edge of the tread surface.

[0012] (5) In the heavy duty pneumatic tire according to any one of (1) to (4) above, the width of the land portion including the equator of the tire is preferably 5% to 65% of the width of the tread surface.

[0013] (6) In the heavy duty pneumatic tire described above in (5), the width of the land portion including the equator of the tire is preferably 12% or more of the width of the tread surface.

[0014] (7) In the heavy duty pneumatic tire described in any one of (1) to (6) above, preferably, the density of the band cord of the edge band is higher than or equal to the density of the band cord in the end region of the full band.

[0015] (8) In the heavy duty pneumatic tire described in any one of (1) to (7) above, the width of the edge band is preferably 15% to 40% of the distance from the equator of the tire to the end of the full band.

[0016] (9) In the heavy-duty pneumatic tire described in any one of (1) to (8) above, preferably, at least three circumferential grooves are formed in the tread, and at least one of the circumferential grooves formed inside the shoulder circumferential groove in the axial direction has a width narrower than that of the shoulder circumferential groove.

[0017] (10) In the heavy-duty pneumatic tire described in any one of (1) to (9) above, preferably, at least three circumferential grooves are formed in the tread, and the depth of at least one of the circumferential grooves formed inside the shoulder circumferential groove in the axial direction is shallower than the depth of the shoulder circumferential groove.

[0018] (11) In the heavy load pneumatic tire described in any one of (1) to (10) above, the axial distance from the shoulder circumferential groove to an end of the full band is preferably 10% or more and 50% or less of the width of the shoulder land portion.

[0019] (12) In the heavy duty pneumatic tire described in any one of (1) to (11) above, the axial distance from an end of the full band to an inner end of the edge band is preferably 10 mm or more.

[0020] (13) In the heavy duty pneumatic tire according to any one of (1) to (12) above, an end of the full band is preferably located inside an end of the belt in the axial direction.

[0021] (14) In the heavy duty pneumatic tire according to any one of (1) to (13) above, at least one belt ply among the plurality of belt plies is preferably located radially inside the full band. Effect of the Invention

[0022] According to the present invention, it is possible to provide a low aspect ratio heavy duty pneumatic tire in which the degree of dimensional change in the tread is small and the difference between the dimensional change in the center portion of the tread and the dimensional change in the shoulder portion of the tread is small. Such a heavy duty pneumatic tire has good resistance to uneven wear. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a cross-sectional view showing a portion of a heavy duty pneumatic tire according to one embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of a portion of the tire of FIG. [Diagram 3] FIG. 3 is a schematic diagram illustrating the configuration of the reinforcing layer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings as appropriate.

[0025] In the present invention, a state in which a tire is mounted on a standard rim, the internal pressure of the tire is adjusted to a standard internal pressure, and no load is applied to the tire is referred to as a standard state.

[0026] In the present invention, unless otherwise specified, the dimensions and angles of each part of the tire are measured in a normal state. The dimensions and angles of each part in the meridian section of the tire, which cannot be measured when the tire is mounted on a regular rim, are measured on the cut surface of the tire obtained by cutting the tire along a plane including the axis of rotation. In this measurement, the tire is set so that the distance between the left and right beads is the same as the distance between the beads of the tire mounted on a regular rim. The tire configuration that cannot be confirmed when the tire is mounted on a regular rim is confirmed on the aforementioned cut surface.

[0027] A genuine rim is a rim that is specified in the standard on which the tire is based. The "standard rim" in the JATMA standard, the "Design Rim" in the TRA standard, and the "Measuring Rim" in the ETRTO standard are genuine rims.

[0028] Normal tire pressure means the internal pressure specified in the standard on which the tire is based. The "maximum air pressure" in the JATMA standard, the "maximum value" listed in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, and the "INFLATION PRESSURE" in the ETRTO standard are normal tire pressures.

[0029] Normal load refers to the load specified in the standard on which the tire is based. The "maximum load capacity" in the JATMA standard, the "maximum value" listed in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, and the "LOAD CAPACITY" in the ETRTO standard are normal loads.

[0030] In the present invention, the "nominal aspect ratio" is the "nominal aspect ratio" included in the "tire designation" defined in JIS D4202 "Automobile tires - designations and specifications".

[0031] In the present invention, the tread of a tire is the part of the tire that comes into contact with the road surface. In this tire, the part of the tread that is axially outward from the shoulder circumferential groove (including the shoulder circumferential groove) is the shoulder part. Also, the part of the tread sandwiched between the shoulder parts is the center part.

[0032] In the present invention, the number of sections of the cords (number of cords) contained in a tire element containing parallel cords per 5 cm width is expressed as the density of the cords contained in this element (unit: ends / 5 cm). Unless otherwise specified, the cord density is obtained in the cross section of the element obtained by cutting the element in a plane perpendicular to the length direction of the cord.

[0033] FIG. 1 shows a portion of a heavy-duty pneumatic tire 2 (hereinafter also simply referred to as "tire 2") according to one embodiment of the present invention. This tire 2 is mounted on vehicles such as trucks and buses. The nominal aspect ratio of this tire 2 is 65% or less. In other words, this tire 2 has a nominal aspect ratio of 65% or less. This tire 2 is a low aspect tire.

[0034] 1 shows a part of a cross section (hereinafter, meridian cross section) of the tire 2 taken along a plane including the rotation axis of the tire 2. In FIG. 1, the left-right direction is the axial direction of the tire 2, and the up-down direction is the radial direction of the tire 2. The direction perpendicular to the plane of FIG. 1 is the circumferential direction of the tire 2. The dashed-dotted line CL represents the equatorial plane of the tire 2.

[0035] Fig. 2 shows a part of the cross section of the tire 2 shown in Fig. 1. Fig. 2 shows the tread of the tire 2. In Fig. 2, the left-right direction is the axial direction of the tire 2, and the up-down direction is the radial direction of the tire 2. The direction perpendicular to the paper surface of Fig. 2 is the circumferential direction of the tire 2.

[0036] The tire 2 is mounted on a rim (not shown). The rim is a regular rim. Air is filled inside the tire 2, and the internal pressure of the tire 2 is adjusted. The tire 2 mounted on the rim is also called a tire-rim assembly. The tire-rim assembly includes a rim and the tire 2 mounted on the rim.

[0037] The tire 2 includes a tread 4 , a pair of sidewalls 6 , a pair of beads 8 , a pair of chafers 10 , a carcass 12 , a pair of cushion layers 14 , an inner liner 16 , a pair of steel fillers 18 , and a reinforcing layer 20 .

[0038] The tread 4 comes into contact with the road surface at its outer surface. This outer surface is a tread surface 22. In Fig. 1, the reference symbol PC denotes an intersection point between the tread surface 22 and the equatorial plane. This intersection point PC is the equator of the tire 2.

[0039] 1, the symbol PE indicates an end of the tread surface 22. The double-headed arrow WT indicates the width of the tread surface 22. The width WT of the tread surface 22 is represented by the axial distance from one end PE of the tread surface 22 to the other end PE of the tread surface 22.

[0040] Although not shown, the tread 4 can include a base portion and a cap portion located radially outward of the base portion. In this case, both the base and cap are made of crosslinked rubber. The base is made of crosslinked rubber with low heat generation. The cap is made of crosslinked rubber that takes into consideration wear resistance, low temperature characteristics, and grip performance.

[0041] In this tire 2, at least two circumferential grooves 28 are formed in the tread 4. Four circumferential grooves 28 are formed in the tread 4 of the tire 2 shown in Fig. 1. These circumferential grooves 28 are arranged in parallel in the axial direction and extend continuously in the circumferential direction.

[0042] Of the four circumferential grooves 28 engraved in the tread 4, the circumferential groove 28 located on the outer side in the axial direction is the shoulder circumferential groove 28s. The circumferential groove 28 located on the inner side of the shoulder circumferential groove 28s in the axial direction is the middle circumferential groove 28m. In the tire 2, the four circumferential grooves 28 are composed of a pair of middle circumferential grooves 28m and a pair of shoulder circumferential grooves 28s.

[0043] In the tire 2, from the viewpoint of ensuring the rigidity of the center portion of the tread, it is preferable that the width of the middle circumferential groove 28m is narrower than the width of the shoulder circumferential groove 28s. In the tire 2, the width of the middle circumferential groove 28m is preferably equal to or greater than 5% and equal to or less than 35% of the width of the shoulder circumferential groove 28s. In the tire 2, the width of the middle circumferential groove 28m is preferably equal to or less than 2% of the width WT of the tread surface 22. The lower limit of the width of the middle circumferential groove 28m is, for example, 1 mm. The width of the circumferential groove 28 is represented by the shortest distance between one edge and the other edge of the circumferential groove 28 .

[0044] 2, the double arrow DGm indicates the depth of the middle circumferential groove 28m, and the double arrow DGs indicates the depth of the shoulder circumferential groove 28s. In the tire 2, from the viewpoint of ensuring the rigidity of the center portion of the tread, the depth DGm of the middle circumferential groove 28m is preferably equal to or shallower than the depth DGs of the shoulder circumferential groove 28s. The depth DGm of the middle circumferential groove 28m is more preferably shallower than the depth DGs of the shoulder circumferential groove 28s. In the tire 2, the depth DGm of the middle circumferential groove 28m is preferably equal to or greater than 60% and equal to or less than 100% of the depth DGs of the shoulder circumferential groove 28s. The depth DGs of the shoulder circumferential groove 28s is, for example, not less than 10 mm and not more than 25 mm. The depth of the circumferential groove 28 is represented by the distance from the tread surface 22 to the bottom of the circumferential groove 28 .

[0045] 2, a double-headed arrow WA indicates the distance from the equator PC to the shoulder circumferential groove 28s of the tire 2. This distance WA is the axial distance between the equator PC and the bottom of the shoulder circumferential groove 28s. In the tire 2, the distance WA from the equator PC to the shoulder circumferential groove 28s is preferably 45% or more and 70% or less of the axial distance HWT from the equator PC to the end PE of the tread surface 22. In this case, it is suitable for improving the uneven wear resistance of the tread.

[0046] The opening of the shoulder circumferential groove 28s during inflation increases as the shoulder circumferential groove 28s moves away from the equator PC of the tire 2. Therefore, when the distance WA exceeds 70% of the distance HWT, the shoulder circumferential groove 28s is too far from the equator PC, so the opening of the shoulder circumferential groove 28s increases, and the dimensional change in the vicinity of the shoulder circumferential groove 28s increases. As a result, uneven wear is likely to occur. When the distance WA exceeds 70% of the distance HWT, the width of the shoulder land portion 30s becomes relatively narrow, and the ground pressure in this portion increases locally, which also makes uneven wear more likely to occur. On the other hand, if the distance WA is less than 45% of the distance HWT, the width of a central land portion 30c (described later) is likely to become narrow, making it difficult to ensure sufficient rigidity in the central portion of the tread 4. An axial distance HWT from the equator PC of the tire 2 to an end PE of the tread surface 22 is half the width WT of the tread surface 22 .

[0047] As described above, at least two circumferential grooves 28 are formed in the tread 4 of the tire 2. As a result, at least three land portions 30 are formed in the tread 4. Four circumferential grooves 28 are formed in the tread 4 of the tire 2 shown in Fig. 1, thereby forming five land portions 30. These land portions 30 are arranged in parallel in the axial direction and extend continuously in the circumferential direction.

[0048] In this tire 2, from the viewpoint of increasing the rigidity of the center portion of the tread, at least one of the at least three land portions 30 is a land portion that includes the equator PC of the tire.

[0049] Of the five land portions 30 formed in the tread 4, the land portion 30 including the equator PC of the tire is the center land portion 30c. The land portion 30 located on the outer side in the axial direction is the shoulder land portion 30s. The shoulder land portion 30s is located on the outer side of the shoulder circumferential groove 28s in the axial direction and includes the edge PE of the tread surface 22. The land portion 30 located between the center land portion 30c and the shoulder land portion 30s in the axial direction is the middle land portion 30m. Between the middle land portion 30m and the shoulder land portion 30s is the shoulder circumferential groove 28s. Between the middle land portion 30m and the center land portion 30c is the middle circumferential groove 28m. In the tire 2 shown in FIGS. 1 and 2, the five land portions 30 are composed of the center land portion 30c, a pair of middle land portions 30m, and a pair of shoulder land portions 30s.

[0050] When the tire 2 is composed of three land portions 30, the land portions 30 are composed of a center land portion 30c and a pair of shoulder land portions 30s. When the tire 2 is composed of six or more land portions 30, the tire 2 is composed of a center land portion 30c, a pair of shoulder land portions 30s, and three or more middle land portions 30m.

[0051] The central land portion 30c is a land portion that includes the equator PC of the tire. The tire 2 having this central land portion 30c has high rigidity in the central portion of the tread 4. The tire 2 is suitable for use as an LRR tire because the central portion of the tread 4 is less susceptible to dimensional change compared to a tire in which the circumferential grooves are located on the equatorial plane.

[0052] 1 and 2, the double-headed arrow WC indicates the width of the center land portion 30c, the double-headed arrow WM indicates the width of the middle land portion 30m, and the double-headed arrow WS indicates the width of the shoulder land portion 30s. In the tire 2, the width WC of the central land portion 30c is preferably equal to or greater than 5% of the width WT of the tread surface 22 and is preferably equal to or less than 65%. If the width WC is less than 5% of the width WT, the rigidity of the center portion of the tread 4 cannot be sufficiently ensured. If the width WC exceeds 65% of the width WT, the position of the shoulder circumferential groove 28s will be far away from the equator PC of the tire 2. Therefore, the shoulder circumferential groove 28s will be easily opened, and the dimensional change in the vicinity of the shoulder circumferential groove 28s will be large. As a result, uneven wear will be easily generated. In addition, the width of the shoulder land portion 30s will be relatively narrow, and the ground pressure in this portion will increase locally, which also makes uneven wear more likely to occur.

[0053] The width WM of the middle land portion 30m is 5% to 18% of the width WT of the tread surface 22. The width WS of the shoulder land portion 30s is 7.5% to 25% of the width WT of the tread surface 22. The width of the land portion 30 is represented by the axial width of the top surface of the land portion 30 which is a part of the tread surface 22. Therefore, the width WC of the center land portion 30c is represented by the axial distance from one end to the other end of the top surface of the center land portion 30c (the axial distance between the inner edges of the middle circumferential grooves 28m). The width WM of the middle land portion 30m is represented by the axial distance from the inner end of the top surface of the middle land portion 30m (the outer edge of the middle circumferential groove 28m) to the outer end of this top surface (the inner edge of the shoulder circumferential groove 28s). The axial width WS of the shoulder land portion 30s is represented by the axial distance from the inner end of the top surface of the shoulder land portion 30s (the outer edge of the shoulder circumferential groove 28s) to the outer end of this top surface (the edge PE of the tread surface 22 in the tire 2).

[0054] It is more preferable that the width WC of the central land portion 30c is 12% or more of the width WT of the tread surface 22. In this case, since the width WC of the central land portion 30c is wide, the rigidity of the central portion of the tread of the tire 2 is high. Therefore, it is suitable for a tire having a reinforcing layer 20 having a configuration described later. It is more preferable that the width WC of the central land portion 30c be 50% of the width WT of the tread surface 22 or less.

[0055] Each sidewall 6 is continuous with an end of the tread 4. The sidewalls 6 extend radially inward from the end of the tread 4. The sidewalls 6 are made of crosslinked rubber.

[0056] Each bead 8 is located radially inward from the sidewall 6. Each bead 8 includes a core 32 and an apex .

[0057] The core 32 extends in the circumferential direction. The core 32 includes wound steel wire. The core 32 has a generally hexagonal cross-sectional shape.

[0058] The apex 34 is located radially outward of the core 32. The apex 34 includes an inner apex 34u and an outer apex 34s. The inner apex 34u extends radially outward from the core 32. The outer apex 34s is located radially outward of the inner apex 34u. The inner apex 34u is made of a hard crosslinked rubber. The outer apex 34s is made of a crosslinked rubber that is softer than the inner apex 34u. The outer apex 34s is softer than the inner apex 34u.

[0059] Each chafer 10 is located axially outward of the bead 8. The chafers 10 are located radially inward of the sidewall 6. The chafers 10 contact a rim (not shown). The chafers 10 are made of crosslinked rubber in consideration of wear resistance.

[0060] The carcass 12 is located inside the tread 4, the sidewall 6, and the chafer 10. The carcass 12 includes at least one carcass ply 36. The carcass 12 of the tire 2 is made up of one carcass ply 36. The carcass ply 36 is folded up around each core 32 from the inside to the outside in the axial direction.

[0061] Although not shown, the carcass ply 36 includes a number of carcass cords arranged in parallel. These carcass cords are covered with a topping rubber. Each carcass cord intersects with the equatorial plane. In the tire 2, the angle that the carcass cords make with the equatorial plane is equal to or greater than 70° and equal to or less than 90°. The carcass 12 has a radial structure. In the tire 2, steel cords are used as the carcass cords.

[0062] Each cushion layer 14 is located at an end of the reinforcing layer 20 between the reinforcing layer 20 and the carcass 12. The cushion layer 14 is made of a soft crosslinked rubber.

[0063] The inner liner 16 is positioned inside the carcass 12. The inner liner 16 constitutes the inner surface of the tire 2. The inner liner 16 is made of crosslinked rubber with excellent air barrier properties. The inner liner 16 maintains the internal pressure of the tire 2.

[0064] Each steel filler 18 is located in a portion of a bead 8. The steel filler 18 is folded back around the core 32 from the inside toward the outside in the axial direction along the carcass ply 36.

[0065] Although not shown, the steel filler 18 includes a number of filler cords arranged in parallel. The filler cords are covered with a topping rubber in the steel filler 18. In the tire 2, a steel cord is used as the filler cord.

[0066] 1 and 2, the reinforcing layer 20 is located radially inside the tread 4. The reinforcing layer 20 is located between the carcass 12 and the tread 4. The reinforcing layer 20 includes a belt 38 and a band 40.

[0067] The belt 38 includes a plurality of belt plies 42 arranged in the radial direction. Each belt ply 42 is arranged such that both ends face each other with the equatorial plane in between. The belt 38 of the tire 2 includes four belt plies 42. The four belt plies 42 include a first belt ply 42A located on the inside in the radial direction, a second belt ply 42B located on the outside of the first belt ply 42A, a third belt ply 42C located on the outside of the second belt ply 42B, and a fourth belt ply 42D located on the outside of the third belt ply 42C.

[0068] In the tire 2, the second belt ply 42B has the widest axial width, and the fourth belt ply 42D has the narrowest axial width. The first belt ply 42A and the third belt ply 42C have the same axial width, or the axial width of the first belt ply 42A is wider than the axial width of the third belt ply 42C.

[0069] The end 38e of the belt 38 of the tire 2 is represented by the end of the belt ply 42 having the widest axial width among the multiple belt plies 42 constituting the belt 38. As described above, in the tire 2, the second belt ply 42B has the widest axial width among the four belt plies 42 constituting the belt 38. The end 38e of the belt 38 of the tire 2 is represented by the end 42Be of the second belt ply 42B having the widest axial width. The end 38e of the belt 38 is also the end 20e of the reinforcing layer 20.

[0070] As shown in FIGS. 1 and 2, in the tire 2, the ends 42e of each of the first belt ply 42A to the fourth belt ply 42D are positioned outside the shoulder circumferential groove 28s in the axial direction.

[0071] In the tire 2, from the viewpoint of ensuring the rigidity of the tread 4 portion, it is preferable that the ratio of the axial width of the belt ply 42 to the width WT of the tread surface 22 is within the following range. A ratio of the axial width of the first belt ply 42A to the width WT of the tread surface 22 is preferably equal to or greater than 0.80 and is preferably equal to or less than 0.90. A ratio of the axial width of the second belt ply 42B to the width WT of the tread surface 22 is preferably equal to or greater than 0.85 and is preferably equal to or less than 0.95. A ratio of the axial width W3 of the third belt ply 42C to the width WT of the tread surface 22 is preferably equal to or greater than 0.80 and is preferably equal to or less than 0.90. A ratio of the axial width W4 of the fourth belt ply 42D to the width WT of the tread surface 22 is preferably equal to or greater than 0.55 and is preferably equal to or less than 0.65. The width of each belt ply 42 is represented by the axial distance from one end 42e of the belt ply 42 to the other end 42e.

[0072] FIG. 3 shows the configuration of the reinforcing layer 20. 3, the left-right direction is the axial direction of the tire 2, and the up-down direction is the circumferential direction of the tire 2. The direction perpendicular to the paper surface is the radial direction of the tire 2. The front side of the paper surface is the radial outer side, and the back side is the radial inner side.

[0073] As shown in Fig. 3, in the tire 2, each belt ply 42 constituting the belt 38 includes a large number of parallel belt cords 44. In Fig. 3, for convenience of explanation, the belt cords 44 are represented by solid lines, but the belt cords 44 are covered with a topping rubber 46. The belt cords 44 of the tire 2 are steel cords.

[0074] In the tire 2, the density of the belt cords 44 in each belt ply 42 (the number of cross sections of the cords per unit width) is preferably 15 ends / 5 cm or greater and 30 ends / 5 cm or less.

[0075] In each belt ply 42, the belt cords 44 are inclined with respect to the circumferential direction. The direction of inclination of the belt cords 44 included in the first belt ply 42A with respect to the circumferential direction (hereinafter referred to as the inclination direction of the first belt ply 42A) is the same as the direction of inclination of the belt cords 44 included in the second belt ply 42B with respect to the circumferential direction (hereinafter referred to as the inclination direction of the second belt ply 42B). The inclination direction of the second belt ply 42B is opposite to the inclination direction of the belt cords 44 included in the third belt ply 42C with respect to the circumferential direction (hereinafter, referred to as the inclination direction of the third belt ply 42C). The inclination direction of the third belt ply 42C is the same as the inclination direction of the belt cords 44 included in the fourth belt ply 42D with respect to the circumferential direction (hereinafter, referred to as the inclination direction of the fourth belt ply 42D). The inclination direction of the first belt ply 42A may be opposite to the inclination direction of the second belt ply 42B, and the inclination direction of the fourth belt ply 42D may be opposite to the inclination direction of the third belt ply 42C. From the viewpoint of ensuring a stable ground contact shape, it is preferable that the inclination direction of the second belt ply 42B is opposite to the inclination direction of the third belt ply 42C.

[0076] In Fig. 3, angle θ1 is an inclination angle of the belt cord 44 included in the first belt ply 42A with respect to the equatorial plane (hereinafter, first inclination angle θ1). Angle θ2 is an inclination angle of the belt cord 44 included in the second belt ply 42B with respect to the equatorial plane (hereinafter, second inclination angle θ2). Angle θ3 is an inclination angle of the belt cord 44 included in the third belt ply 42C with respect to the equatorial plane (hereinafter, third inclination angle θ3). Angle θ4 is an inclination angle of the belt cord 44 included in the fourth belt ply 42D with respect to the equatorial plane (hereinafter, fourth inclination angle θ4).

[0077] In this tire 2, the first inclination angle θ1, the second inclination angle θ2, the third inclination angle θ3, and the fourth inclination angle θ4 are preferably 10° or more and 60° or less. From the viewpoint of effectively restraining the movement of the tire 2 and ensuring a stable ground contact shape, the first inclination angle θ1 is preferably 40° or more and 60° or less. The second inclination angle θ2 is preferably 10° or more and 20° or less. The third inclination angle θ3 is preferably 10° or more and 20° or less. The fourth inclination angle θ4 is preferably 10° or more and 60° or less.

[0078] The band 40 includes a full band 48 and a pair of edge bands 50 . 1 to 3, the full band 48 has two ends 48e that face each other across the equatorial plane. The pair of edge bands 50 are disposed axially spaced apart from each other across the equatorial plane. In the tire 2, a fourth belt ply 42D that forms part of the belt 38 is located between the left and right edge bands 50.

[0079] Each edge band 50 is located between the tread 4 and the full band 48. The edge band 50 is located radially outward of the end 48e of the full band 48. In the axial direction, the inner end 50ue of the edge band 50 is located inside the end 48e of the full band 48. The outer end 50se of the edge band 50 is located axially outward of the end 48e of the full band 48. The position of the outer end 50se of the edge band 50 may coincide with the position of the end 48e of the full band 48 in the axial direction. The edge band 50 overlaps the end 48e of the full band 48 in the radial direction.

[0080] 2 and 3, the full band 48 is composed of two end regions 48B located axially outward and a central region 48A sandwiched between the two end regions 48B. The central region 48A is located axially inward of the end regions 48B. In the tire 2, both end portions 48Ae of the central region 48A are located axially inside the shoulder circumferential groove 28s. The both end portions 48Ae of the central region 48A do not overlap with the shoulder circumferential groove 28s in the radial direction. If the end 48Ae overlaps with the shoulder circumferential groove 28s in the radial direction, the rigidity difference on the lower side (radially inner side) of the circumferential groove becomes large, which promotes bending of the groove bottom and makes it easier for strain to accumulate at the groove bottom. This raises concerns about the occurrence of TGC (tread groove cracks) and a decrease in durability of the tire 2. In addition, the promotion of bending of the groove bottom of the shoulder circumferential groove makes the shoulder land portion 30s easier to move, making it easier for track wear to occur on the axial inner side of the shoulder land portion 30s. Furthermore, if the end 48Ae is located on the axial outer side of the shoulder circumferential groove 28s, the dimensional change of the shoulder portion of the tread cannot be sufficiently suppressed.

[0081] Furthermore, it is preferable that the two end portions 48Ae of the central region 48A do not overlap with the middle circumferential groove 28m in the radial direction. If the end portions 48Ae overlap with the middle circumferential groove 28m in the radial direction, strain is likely to accumulate in the groove bottom of the middle circumferential groove 28m. In this case, too, there is a concern about the occurrence of TGC and a decrease in durability of the tire 2. Both end portions 48Ae of the central region 48A are preferably located between the middle circumferential groove 28m and the shoulder circumferential groove 28s in the axial direction.

[0082] In the tire 2, an axially outer end 48Be of the end region 48B is located axially outward of the shoulder circumferential groove 28s. The axially outer end 48Be of the end region 48B does not overlap with the shoulder circumferential groove 28s in the radial direction. The axially outer end 48Be of the end region 48B is also the end 48e of the full band 48.

[0083] 2, the double-headed arrow WF indicates the width of the full band 48. The width of the full band 48 is represented by the axial distance from one end 48e to the other end 48e of the full band 48. The double-headed arrow WFC indicates the width of the central region 48A. The width of the central region 48A is represented by the axial distance from one end 48Ae to the other end 48Ae of the central region 48A. The width WFC of the central region 48A is preferably equal to or greater than 20% of the width WT of the tread 4. If the width WFC is less than 20% of the width WT, the dimensional change of the center portion of the tread 4 tends to be excessively suppressed.

[0084] As shown in Fig. 3, the full band 48 and the pair of edge bands 50 constituting the band 40 include a spirally wound band cord 52. In Fig. 3, the band cord 52 is represented by a solid line for convenience of explanation, but the band cord 52 is covered with a topping rubber 54.

[0085] In the tire 2, the band cord 52 is a steel cord or a cord made of an organic fiber (hereinafter, referred to as an organic fiber cord). When an organic fiber cord is used as the band cord 52, examples of the organic fiber include nylon fiber, polyester fiber, rayon fiber, and aramid fiber. From the viewpoint of rigidity, the band cord 52 is preferably a steel cord. In the tire 2, the same cord may be used for the band cord 52 of the full band 48 and the band cord 52 of the edge band 50, or different cords may be used. The band cords 52 used for the full band 48 and the edge band 50 are determined according to the specifications of the tire 2.

[0086] As described above, the full band 48 includes the spirally wound band cord 52. The full band 48 has a jointless structure. In the full band 48, the angle that the band cord 52 makes with the circumferential direction is preferably 5° or less, and more preferably 2° or less. The band cord 52 of the full band 48 extends substantially in the circumferential direction. In the full band 48, the central region 48A and the end regions 48B may be wound continuously with the same band cord, or different band cords may be wound in the central region 48A and the end regions 48B.

[0087] As described above, the edge band 50 includes the spirally wound band cord 52. The edge band 50 has a jointless structure. In the edge band 50, the angle that the band cord 52 makes with the circumferential direction is preferably 5° or less, more preferably 2° or less. The band cord 52 of the edge band 50 extends substantially in the circumferential direction.

[0088] In the tire 2, the density of the band cords 52 in the central region 48A (hereinafter also referred to as band central density) is lower than the density of the band cords 52 in the end regions 48B (hereinafter also referred to as band end density). Specifically, in the full band 48 of the tire 2, the central region 48A has a lower number of cross sections of the band cords 52 per 5 cm width than the end regions 48B.

[0089] In this tire 2, the band end density is preferably 1.2 times or more and 2.0 times or less than the band center density. In this case, it is suitable for reducing the difference in dimensional change between the shoulder portion of the tread 4 and the center portion of the tread 4. When the band end density is less than 1.2 times the band center density, in a tire with high center rigidity such as tire 2, the full band 48 exerts a strong binding force on the center. Therefore, even though the edge band 50 is provided, the shoulder portion is more susceptible to dimensional change than the center portion, making it difficult to equalize the tire's ground contact pressure.

[0090] On the other hand, when the band end density is more than 2.0 times the band center density, the difference in rigidity between the tread center and shoulder is large, and the shoulder circumferential groove 28s tends to bend even in a tire with a high rigidity in the center like tire 2. When the shoulder circumferential groove 28s tends to bend, distortion tends to accumulate in the shoulder circumferential groove, and the accumulated distortion causes TGC and reduces durability. Furthermore, when the shoulder circumferential groove 28s becomes more easily bent, the shoulder land portion 30s also becomes more easily moved, and as a result, the axially inner portion of the shoulder land portion becomes more easily worn.

[0091] In the full band 48, the preferred band center density is 10 ends / 5 cm or more and 30 ends / 5 cm or less.

[0092] In the edge band 50, the density of the band cords 52 is preferably the same as or higher than the band end density of the full band 48. In this case, the edge band 50 is suitable for suppressing dimensional changes in the shoulder portion of the tread by the effect of suppressing breakage of the band cord 52 of the full band 48 and the restraining force that the edge band 50 itself imparts to the tread.

[0093] In the edge band 50, a preferred density of the band cord 52 is 20 ends / 5 cm or more and 35 ends / 5 cm or less. The density of the band cord 52 of the edge band 50 is represented by the number of cross sections of the band cord 52 contained per 5 cm width of the edge band 50 in a cross section of the edge band 50 along a plane perpendicular to the extension direction of the band cord 52.

[0094] In the tire 2, the end 42Be of the second belt ply 42B and the end 42Ce of the third belt ply 42C are each covered with a rubber layer 56. Two more rubber layers 56 are disposed between the end 42Be of the second belt ply 42B and the end 42Ce of the third belt ply 42C, which are covered with the rubber layer 56. In the tire 2, an edge member 58 made of a total of four rubber layers 56 is configured between the end 42Be of the second belt ply 42B and the end 42Ce of the third belt ply 42C.

[0095] The edge member 58 is made of crosslinked rubber. The edge member 58 contributes to maintaining a gap between the end 42Be of the second belt ply 42B and the end 42Ce of the third belt ply 42C. In the tire 2, a change in the positional relationship between the end 42Be of the second belt ply 42B and the end 42Ce of the third belt ply 42C caused by running is suppressed. The edge member 58 is a part of the reinforcing layer 20. The reinforcing layer 20 of the tire 2 includes a pair of edge members 58 in addition to the belt 38 and the band 40.

[0096] As described above, the full band 48 has both ends 48e that face each other across the equatorial plane. The full band 48 extends in the axial direction from the equatorial plane toward each end 48e. The ends 48e of the full band 48 are located outside the shoulder circumferential groove 28s in the axial direction. The full band 48 is located inside the shoulder circumferential groove 28s in the radial direction. Even though the tire 2 has a low aspect ratio, the full band 48 effectively suppresses deformation near the shoulder circumferential groove 28s. Since changes in the shape of the tire 2, for example, the outline (also called the case line) of the carcass 12, are suppressed, changes in the ground contact shape are suppressed.

[0097] As described above, the full band 48 of the tire 2 is composed of the central region 48A in which the density of the band cord 52 is relatively low, and the end region 48B in which the density of the band cord 52 is relatively high. In addition, the tire 2 is also provided with a pair of edge bands spaced apart in the axial direction across the equatorial plane. Therefore, the difference between the dimensional change in the center portion and the dimensional change in the shoulder portion of the tread can be reduced, and uneven wear can be suppressed.

[0098] Furthermore, in this tire 2, the edge band 50 is located radially outboard of the end 48e of the full band 48. The edge band 50 restrains the end 48e of the full band 48. Since the tension fluctuation of the band cord 52 included in the full band 48 is suppressed, the occurrence of breakage of the band cord 52 due to this tension fluctuation is suppressed. The full band 48 of this tire 2 can stably exert the function of suppressing dimensional change. Furthermore, the edge band 50 is narrower than the full band 48. Therefore, the band cord 52 of the edge band 50 is less likely to experience tension fluctuations like those of the full band 48. Breakage is less likely to occur in the band cord 52 of the edge band 50.

[0099] 2, the double-headed arrow WE indicates the width of the edge band 50. The width of the edge band 50 is represented by the axial distance from the inner end 50ue to the other end 50se of the edge band 50. In the tire 2, the width WE of the edge band 50 is preferably 15% to 40% of half (also called 1 / 2 width) HWF of the width WF of the full band 48. In this case, the edge band 50 can exert the effect of providing an edge band without suppressing the dimensional change of the center portion of the tread 4.

[0100] If the width WE of the edge band 50 is less than 15% of the 1 / 2 width HWF of the full band 48, the edge band 50 will be weak in suppressing dimensional changes in the shoulder portion. Therefore, the edge band 50 may not be able to fully exert its effect. On the other hand, if the width WE of the edge band 50 exceeds 40% of the 1 / 2 width HWF of the full band 48, the effect of suppressing dimensional changes is likely to extend not only to the shoulder portion of the tread but also to the center portion. Therefore, the difference in dimensional changes between the shoulder portion and the center portion does not decrease, and uneven wear resistance is difficult to improve.

[0101] In this tire 2, the dimensional change of the tire 2 itself during running is suppressed by the full band 48 and the edge band 50. Furthermore, the difference in dimensional change between the center portion and the shoulder portion of the tread 4 is suppressed. In this tire 2, the occurrence of uneven wear, which was a concern in conventional tires, is suppressed.

[0102] In FIG. 2, the double-headed arrow SF indicates the shoulder circumferential groove 28s, more specifically, the axial distance from the outer edge of the shoulder circumferential groove 28s to the end 48e of the full band 48. In the tire 2, the axial distance SF from the shoulder circumferential groove 28s to the end 48e of the full band 48 is preferably equal to or greater than 10% of the axial width WS of the shoulder land portion 30s. In this case, the end 48e of the full band 48 is disposed at an appropriate interval from the bottom of the shoulder circumferential groove 28s. In the tire 2, the occurrence of damage originating from the bottom of the shoulder circumferential groove 28s is suppressed. In addition, since the width of the full band 48 is ensured, the full band 48 contributes to suppressing dimensional changes in the tread 4. From this viewpoint, the distance SF is more preferably 15% or more of the width WS.

[0103] In the tire 2, the axial distance SF from the shoulder circumferential groove 28s to the end 48e of the full band 48 is preferably equal to or less than 50% of the axial width WS of the shoulder land portion 30s. In this case, the end 48e of the full band 48 is disposed away from the end portion of the tread 4 that actively moves during running, so that fluctuations in tension of the band cord 52 included in the full band 48 are suppressed. In the tire 2, the occurrence of breakage of the band cord 52 included in the full band 48 is suppressed. The full band 48 of the tire 2 contributes to suppressing dimensional changes. From this viewpoint, the distance SF is more preferably equal to or less than 35% of the width WS, and further preferably equal to or less than 25% of the width WS.

[0104] In FIG. 2, the double arrow WD indicates the axial distance from the end 48e of the full band 48 to the inner end 50ue of the edge band 50. The axial distance WD is preferably 10 mm or more. This allows the edge band 50 to effectively restrain the end 48e of the full band 48. Since the tension fluctuation of the band cord 52 included in the full band 48 is suppressed, the occurrence of breakage of the band cord 52 due to the tension fluctuation is suppressed. The full band 48 of the tire 2 can more stably exert the function of suppressing dimensional change. From this viewpoint, the axial distance WD is more preferably 20 mm or more.

[0105] In this tire 2, the position of the inner end 50ue of the edge band 50 is appropriately determined in consideration of the contribution to the occurrence of damage starting from the bottom of the shoulder circumferential groove 28s. Therefore, a preferable upper limit of this axial distance WD is not set.

[0106] In the tire 2, the end 48e of the full band 48 is located inside the end 38e of the belt 38 in the axial direction, and the belt 38 is wider than the full band 48. In this case, the belt 38 restrains the end 48e of the full band 48. The belt 38 contributes to suppressing the tension fluctuation of the band cord 52 included in the full band 48. When the tension fluctuation of the band cord 52 is suppressed, the occurrence of breakage of the band cord 52 is suppressed, so that the full band 48 can stably exert the function of suppressing dimensional change. From this viewpoint, it is preferable that the end 48e of the full band 48 is located inside the end 38e of the belt 38 in the axial direction.

[0107] A force acts on the full band 48 of the tire 2 so as to spread from the inside to the outside in the radial direction. This force generates tension in the band cord 52 included in the full band 48. In this tire 2, the second belt ply 42B is located on the inside of the full band 48 in the radial direction.

[0108] In the tire 2, the second belt ply 42B suppresses the force acting on the full band 48, so that the tension of the band cord 52 included in the full band 48 is appropriately maintained. The second belt ply 42B contributes to suppressing the tension fluctuation of the band cord 52. Since the second belt ply 42B is wider than the full band 48, the tension fluctuation of the band cord 52 is effectively suppressed. In the tire 2, the band cord 52 of the full band 48 is unlikely to break. The full band 48 can stably exert the function of suppressing the shape change. From this viewpoint, it is preferable that at least one belt ply 42 of the multiple belt plies 42 constituting the belt 38 is located inside the full band 48 in the radial direction. It is more preferable that at least one belt ply 42 located inside the full band 48 has a width wider than the width WF of the full band 48.

[0109] In addition, in the tire 2, from the viewpoint of suppressing tension fluctuations in the band cord 52 of the full band 48 and making it difficult for the band cord to break due to tension fluctuations, it is more preferable that in the tire 2, the second belt ply 42B wider than the full band 48 is located inside the full band 48 in the radial direction, and the third belt ply 42C wider than the full band 48 is located outside the full band 48.

[0110] Furthermore, from a similar viewpoint, in the tire 2, it is further preferable that the first belt ply 42A, the second belt ply 42B and the third belt ply 42C have a width wider than the width WF of the full band 48, that the first belt ply 42A and the second belt ply 42B are located inside the full band 48 in the radial direction, that the third belt ply 42C is located outside the full band 48, and that the pair of edge bands 50 are each located outside the third belt ply 42C in the radial direction.

[0111] In particular, from a similar viewpoint, in the tire 2, the multiple belt plies 42 constituting the belt 38 include a first belt ply 42A located on the inside in the radial direction, a second belt ply 42B located on the outside of the first belt ply 42A, and a third belt ply 42C located on the outside of the second belt ply 42B, and the first belt ply 42A, the second belt ply 42B, and the third belt ply 42C have a width wider than the width WF of the full band 48, and in the radial direction, the first belt ply 42A and the second belt ply 42B are located on the inside of the full band 48, and the third belt ply 42C is located on the outside of the full band 48, and in the radial direction, it is particularly preferable that the edge band 50 located on the outside of the full band 48 overlaps with the end 48e of the full band 48 via the third belt ply 42C.

[0112] As is clear from the above description, the present invention provides a heavy-duty pneumatic tire 2 having good resistance to uneven wear. The present invention exerts a remarkable effect on a heavy-duty pneumatic tire 2 having a nominal aspect ratio of 65% or less and high rigidity in the center portion of the tread. [Industrial Applicability]

[0113] The techniques described above for reducing the difference between the dimensional change in the center portion and the dimensional change in the shoulder portions and improving resistance to uneven wear can be applied to various types of tires. [Explanation of symbols]

[0114] 2. Tires 4. Tread 20... Reinforcement layer 20e: End of reinforcing layer 20 22 Tread surface 28, 28s, 28m...Circumferential groove 30, 30s, 30m, 30c...Land 38. Belt 40...Band 40e: End of band 40 42 Belt ply 44 Belt cord 48...Full Band 48A...Central area 48B...End area 48e...End of full band 48 50···Edge band 50se: Outer end of edge band 50 50ue: Inner end of edge band 50 52 Band cord

Claims

1. A nominal aspect ratio of 65% or less; The tire has a tread that comes into contact with a road surface, and a reinforcing layer that is located radially inside the tread, At least two circumferential grooves are cut into the tread to form at least three land portions arranged in parallel in the axial direction, a circumferential groove located on an outer side in the axial direction among the at least two circumferential grooves is a shoulder circumferential groove, a land portion located on an outer side of the shoulder circumferential groove in the axial direction is a shoulder land portion, and one of the at least three land portions is a land portion including an equator of the tire, The reinforcing layer includes a belt including a number of parallel belt cords and a band including a spirally wound band cord, The belt includes a plurality of belt plies arranged in a radial direction, The band includes a full band having both ends facing each other across an equator plane, and a pair of edge bands located radially outward of the ends of the full band, The full band includes two end regions located axially outward and a central region sandwiched between the two end regions, and a density of the band cord in the central region is lower than a density of the band cord in the end regions, an end of the full band is located outside the shoulder circumferential groove in the axial direction; In the axial direction, an inner end of the edge band is located outside the shoulder circumferential groove. Heavy duty pneumatic tires.

2. The width of the central region is 20% or more of the width of the tread surface, The heavy load pneumatic tire according to claim 1 , wherein an end of the central region is located axially inside the shoulder circumferential groove.

3. 3. The heavy-duty pneumatic tire according to claim 1, wherein a density of the band cord in the end regions is 1.2 to 2.0 times a density of the band cord in the central region.

4. 3. The heavy-duty pneumatic tire according to claim 1, wherein a distance from the tire equator to the shoulder circumferential groove is 45% or more and 70% or less of a distance from the tire equator to an edge of the tread surface.

5. 3. The heavy-duty pneumatic tire according to claim 1, wherein a width of a land portion including an equator of the tire is 5% to 65% of a width of the tread surface.

6. 6. The heavy-duty pneumatic tire according to claim 5, wherein a width of the land portion including the equator of the tire is 12% or more of a width of the tread surface.

7. 3. The heavy-duty pneumatic tire according to claim 1, wherein a density of the band cord of the edge band is higher than or equal to a density of the band cord in an end region of the full band.

8. 3. The heavy-duty pneumatic tire according to claim 1, wherein a width of the edge band is 15% or more and 40% or less of a distance from an equator of the tire to an end of the full band.

9. At least three circumferential grooves are formed in the tread, 3. The heavy-duty pneumatic tire according to claim 1, wherein at least one of the circumferential grooves cut inside the shoulder circumferential groove in the axial direction has a width narrower than a width of the shoulder circumferential groove.

10. At least three circumferential grooves are formed in the tread, 3. The heavy-duty pneumatic tire according to claim 1, wherein a depth of at least one of the circumferential grooves cut inside the shoulder circumferential groove in the axial direction is shallower than a depth of the shoulder circumferential groove.

11. The heavy-duty pneumatic tire according to claim 1 or 2, wherein an axial distance from the shoulder circumferential groove to an end of the full band is 10% or more and 50% or less of a width of the shoulder land portion.

12. 3. The heavy-duty pneumatic tire according to claim 1, wherein an axial distance from an end of the full band to an inner end of the edge band is 10 mm or more.

13. The heavy duty pneumatic tire according to claim 1 or 2, wherein an end of the full band is located inside an end of the belt in the axial direction.

14. 3. The heavy-duty pneumatic tire according to claim 1, wherein at least one of the plurality of belt plies is located inside the full band in the radial direction.

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