JP2015214286A - Rebuilt tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rebuilt tire capable of improving uneven wear resistant performance of the tire.SOLUTION: A rebuilt tire 10 is configured so that a tread width TW and a tire total width SW satisfy the relationship of 0.65≤TW/SW≤0.85. In addition, a distance SDH from a rim diameter measurement point P to a tire maximum width position Q and a tire cross section height SH satisfy the relationship of 0.45≤SDH/SH≤0.65. In addition, a distance Le from a tire equator surface CL to an edge part of a land part 32 divided by an outermost peripheral main groove 22 on outside of a tire width direction, and a distance Lh from the tire equator surface CL to an end of a cross belt 142 which has a narrow width, satisfy the relationship of 0.60≤Le/Lh≤0.85.

Description

  The present invention relates to a retreaded tire, and more particularly to a retreaded tire that can improve uneven wear resistance performance of the tire.

  Conventionally, rehabilitation has been performed on heavy-duty tires mounted on trucks and buses, but in recent years, rehabilitation is also being performed on light truck tires. As such a retread tire for a small truck, a technique described in Patent Document 1 is known.

JP 2009-0410179 A

  On the other hand, even in the retreaded tire, there is a problem to improve the uneven wear resistance performance of the tire.

  Therefore, the present invention has been made in view of the above, and an object of the present invention is to provide a retread tire that can improve the uneven wear resistance performance of the tire.

  In order to achieve the above object, a retread tire according to the present invention includes a tread and a base tire, and the tread has at least three circumferential main grooves extending in the tire circumferential direction, and the circumferential main groove. A plurality of land portions divided into a tread surface, and the base tire includes a carcass layer and a belt layer disposed on the outer side in the tire radial direction of the carcass layer, and the belt layer A retread tire having a pair of cross belts and a belt cover disposed on the outer side in the tire radial direction of the pair of cross belts, wherein the outer circumferential main groove is the outermost circumferential main When referred to as a groove, the tread width TW and the tire total width SW have a relationship of 0.65 ≦ TW / SW ≦ 0.85, and the tire radial direction from the rim diameter measurement point to the tire maximum width position Distance SDH The tire cross-section height SH has a relationship of 0.45 ≦ SDH / SH ≦ 0.65, and the edge of the land portion on the outer side in the tire width direction that is partitioned from the tire equatorial plane into the outermost circumferential main groove The distance Le to the portion and the distance Lh from the tire equatorial plane to the end of the narrow cross belt have a relationship of 0.60 ≦ Le / Lh ≦ 0.85.

  In the retreaded tire according to the present invention, since the ratio TW / SW and the ratio SDH / SH that define the profile are optimized, there is an advantage that the ground contact shape of the tire is optimized and the uneven wear resistance performance of the tire is improved. . Moreover, the rigidity of the shoulder land portion is appropriately ensured by optimizing the positional relationship (distance Le, Lh) between the edge portion of the shoulder land portion and the end portion of the narrow cross belt. Thereby, there is an advantage that uneven wear of the shoulder land portion is suppressed, and the uneven wear resistance performance of the tire is further improved.

FIG. 1 is a cross-sectional view in the tire meridian direction showing a retread tire according to an embodiment of the present invention. FIG. 2 is an explanatory view showing the operation of the retread tire described in FIG. 1. FIG. 3 is a plan view showing a tread surface of the retread tire described in FIG. 1. FIG. 4 is an enlarged view showing a main part of the retread tire described in FIG. 1. FIG. 5 is an enlarged view showing a main part of the retread tire described in FIG. 1. FIG. 6 is an explanatory view showing a modified example of the retread tire described in FIG. 1. FIG. 7 is a chart showing the results of the performance test of the retreaded tire according to the embodiment of the present invention. FIG. 8 is a chart showing the results of the performance test of the retreaded tire according to the embodiment of the present invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Further, the constituent elements of this embodiment include those that can be replaced while maintaining the identity of the invention and that are obvious for replacement. In addition, a plurality of modifications described in this embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

[Rehabilitated tire]
FIG. 1 is a cross-sectional view in the tire meridian direction showing a retread tire according to an embodiment of the present invention. The same figure has shown sectional drawing of the one-side area | region of a tire radial direction. Moreover, the figure has shown the retreaded tire for light trucks as an example.

  In the figure, the cross section in the tire meridian direction means a cross section when the tire is cut along a plane including a tire rotation axis (not shown). Reference sign CL denotes a tire equator plane, which is a plane that passes through the center point of the tire in the tire rotation axis direction and is perpendicular to the tire rotation axis. Moreover, the code | symbol T is a tread end. Further, the tire width direction means a direction parallel to the tire rotation axis, and the tire radial direction means a direction perpendicular to the tire rotation axis.

  The retread tire 10 is a tire that is reused by replacing the tread rubber of a tire whose remaining groove has reached the end of its life. For example, the retread tire 10 is used for a heavy load tire, a small truck tire, or the like.

  As shown in FIG. 1, the retread tire 10 includes a tread 20 and a base tire 30. The tread 20 is a rubber member that constitutes the tread portion, and is newly added when the retread tire 10 is manufactured. The base tire 30 is formed by cutting off part of the tread rubber and part of the sidewall rubber of the tire whose remaining grooves have reached the end of life, and buffing the outer peripheral surface thereof. The retread tire 10 is manufactured by a remolding method or a precure method, as will be described later.

  Further, the retread tire 10 includes a pair of bead cores 11 and 11, a pair of bead fillers 12 and 12, a carcass layer 13, and a plurality of belt plies 141 to 143 (in FIG. 1, a pair of bead cores 11 and 11). Belt layer 14 formed by laminating cross belts 141 and 142 and belt cover 143), tread rubber 15 constituting a tread portion, side wall rubbers 16 and 16 constituting left and right sidewall portions, and left and right bead portions. Rim cushion rubbers 17 and 17 are provided. Among these components, the tread rubber 15 includes a newly added tread 20 and a residual tread 301 of the base tire 30. Further, the sidewall rubber 16 and the rim cushion rubber 17 are included in the base tire 30.

  In this embodiment, the circumferential main groove 22 located on the outermost side in the tire width direction is referred to as the outermost circumferential main groove. The land portion 32 on the outer side in the tire width direction adjacent to the outermost circumferential main groove is referred to as a shoulder land portion.

[Rehabilitated tire by remolding method]
In the retread tire 10 manufactured by the remolding method, the tread 20 is unvulcanized rubber at the material stage, and constitutes the tread portion of the retread tire 10 at the product stage. Further, the tread 20 can be made of, for example, a strip-shaped unvulcanized rubber, a plate-shaped unvulcanized rubber, or the like.

  The remolded tire 10 by this remolding method is manufactured by the following process (not shown).

  First, the tread rubber of the tire whose remaining groove has reached the end of its life is cut out, and the outer peripheral surface thereof is buffed to obtain the base tire 30. This buffing process is performed in a state where an internal pressure is applied to the tire.

  Next, the tread 20 is disposed on the outer peripheral surface of the base tire 30. At this time, the tread 20 may be formed by (a) strip-shaped unvulcanized rubber being spirally wound around the outer peripheral surface of the base tire 30, or (b) a plate-shaped rubber member serving as a basis. The tread 20 may be formed by being wound around the outer peripheral surface of the base tire 30 and spirally winding a strip-like unvulcanized rubber around the outer periphery. In the case of the latter (b), the time required for the installation process of the tread 20 can be shortened compared to the case of the former (a).

  Next, a vulcanization process is performed. In this vulcanization step, the assembly of the tread 20 and the base tire 30 is filled into a tire vulcanization mold (not shown) having a tire molding die. Next, the assembly of the tread 20 and the base tire 30 is expanded radially outward by the pressurizing device, and the tread 20 is pressed against the tire molding die. Further, the assembly of the tread 20 and the base tire 30 is heated, so that the tread 20 is vulcanized and the shape of the tire molding die is transferred to the tread 20. Thereafter, the vulcanized tire is taken out from the tire vulcanization mold.

[Rehabilitated tire by precure method]
On the other hand, in the retreaded tire 10 manufactured by the precure method, the tread 20 is a tread rubber (precure tread) that has been vulcanized in the material stage, and constitutes a tread portion of the retreaded tire 10. Further, the tread 20 has a plate-like structure or an annular structure, and has a tread pattern when the retread tire 10 is new on its outer peripheral surface in advance.

  The retreaded tire 10 by this precure method is manufactured by the following processes (not shown).

  First, the tread rubber of the tire whose remaining groove has reached the end of its life is cut out, and the outer peripheral surface thereof is buffed to obtain the base tire 30. This buffing process is performed in a state where an internal pressure is applied to the tire.

  Next, cushion rubber (not shown) is affixed over the entire circumference of the outer peripheral surface of the base tire 30. The cushion rubber is a sheet-like unvulcanized rubber at the material stage. Thereafter, the tread 20 is disposed on the outer peripheral surface of the base tire 30 and bonded to the base tire 30 via cushion rubber.

  At this time, when the tread 20 has a plate-like structure, the tread 20 is wound around the base tire 30 and is fixed by temporarily fixing both ends by a fixing member (not shown). On the other hand, in the configuration in which the tread 20 has an annular structure, the tread 20 is expanded and contracted by a dedicated expansion / contraction diameter device (not shown) and is fitted to the outer periphery of the base tire 30.

  Next, a vulcanization process is performed. In this vulcanization process, the assembly of the tread 20 and the base tire 30 is housed in a vulcanization can (not shown), the air in the vulcanization can is sucked in vacuum, and then heated and pressurized. The cushion rubber is vulcanized. Thereafter, the vulcanized tire is taken out from the vulcanization can.

[Tire profile]
Conventionally, rehabilitation has been performed on heavy-duty tires mounted on trucks and buses, but in recent years, rehabilitation is also being performed on light truck tires.

  Further, since the retread tire uses a tire whose remaining groove has reached the end of its life as a base tire, the tire profile tends to be non-uniform in the tire width direction. For this reason, there is a problem that uneven wear (center uneven wear and shoulder uneven wear) is likely to occur.

  Therefore, the retreaded tire 10 employs the following configuration in order to improve the uneven wear resistance particularly in a small truck tire.

  In this retread tire 10, in FIG. 1, the tread width TW and the total tire width SW have a relationship of 0.65 ≦ TW / SW ≦ 0.85. Further, the ratio TW / SW is preferably in the range of 0.70 ≦ TW / SW ≦ 0.80, and more preferably in the range of 0.73 ≦ TW / SW ≦ 0.78.

  The tread width TW is measured as a linear distance between both ends of a tread pattern portion of the tire when the tire is mounted on a specified rim to apply a specified internal pressure and is in a no-load state.

  The total tire width SW is measured as the linear distance between the sidewalls (including all parts such as the pattern on the tire side and characters) when the tire is mounted on the specified rim to provide the specified internal pressure and the load is not loaded. Is done.

  Further, in FIG. 1, the distance SDH in the tire radial direction from the measurement point P of the rim diameter to the tire maximum width position Q and the tire cross-section height SH have a relationship of 0.45 ≦ SDH / SH ≦ 0.65. Have. The ratio SDH / SH is preferably in the range of 0.50 ≦ SDH / SH ≦ 0.60, and more preferably in the range of 0.52 ≦ SDH / SH ≦ 0.58.

  The tire maximum width position Q refers to the maximum width position of the tire cross-sectional width specified by JATMA. Note that the tire cross-sectional width is measured as a no-load state while applying a specified internal pressure by mounting the tire on a specified rim.

  The tire cross-section height SH is a distance that is ½ of the difference between the tire outer diameter and the rim diameter. The tire cross-section height SH is measured as an unloaded condition while a tire is mounted on a prescribed rim and a prescribed internal pressure is applied.

  FIG. 2 is an explanatory view showing the operation of the retread tire described in FIG. 1. The figure shows the evaluation results of the test tires of the conventional example and Example A.

  The evaluation results in FIG. 2 were obtained as follows. First, the maximum principal strain [%] of the peripheral rubber at the end portions of the cross belts 141 and 142 is measured while a tire is mounted on a prescribed rim and a prescribed internal pressure is applied and no load is applied. In addition, the fluctuation range of the main strain is the main strain [%] of the peripheral rubber at the ends of the cross belts 141 and 142 when the tire is mounted on the specified rim and the specified internal pressure and the specified load are applied. Is measured at each position in the tire circumferential direction, and is calculated as the difference between the maximum value and the minimum value of these measured values. Then, based on the calculation result, index evaluation using the conventional example as a reference (100) is performed.

  In this retreaded tire 10, the ratio TW / SW and the ratio SDH / SH are optimized, and the profile from the tire equatorial plane CL to the shoulder portion becomes flat. Thereby, the contact pressure in the tire width direction at the time of tire contact is made uniform, and the occurrence of uneven center wear and uneven shoulder wear is suppressed.

[Tread pattern]
FIG. 3 is a plan view showing a tread surface of the retread tire described in FIG. 1. The figure shows a tread pattern of an all-season tire. In the figure, the tire circumferential direction refers to the direction around the tire rotation axis.

  The retread tire 10 includes a plurality of circumferential main grooves 21 and 22 extending in the tire circumferential direction, and a plurality of land portions 31 and 32 partitioned by the circumferential main grooves 21 and 22 in a tread portion. (See FIG. 3).

  Here, the left and right circumferential main grooves 22 and 22 on the outermost side in the tire width direction are referred to as outermost circumferential main grooves. Further, the tread portion center region and the tread portion shoulder region are defined with the left and right outermost circumferential main grooves 22 and 22 as boundaries.

  The circumferential main groove is a circumferential groove having a wear indicator indicating the end of wear, and generally has a groove width of 5.0 [mm] or more and a groove depth of 7.5 [mm] or more.

  The groove width is measured as the maximum value of the distance between the left and right groove walls at the groove opening in a no-load state in which the tire is mounted on the prescribed rim and filled with the prescribed internal pressure. In the configuration where the land part has a notch part or a chamfered part at the edge part, the groove width is based on the intersection of the tread surface and the extension line of the groove wall in a cross-sectional view in which the groove length direction is a normal direction. Measured. In the configuration in which the groove extends in a zigzag shape or a wave shape in the tire circumferential direction, the groove width is measured with reference to the center line of the amplitude of the groove wall.

  The groove depth is measured as the maximum value of the distance from the tread surface to the groove bottom in an unloaded state in which the tire is mounted on the specified rim and filled with the specified internal pressure. Moreover, in the structure which a groove | channel has a partial uneven | corrugated | grooved part and a sipe in a groove bottom, groove depth is measured except these.

  Here, the prescribed rim refers to “applied rim” prescribed in JATMA, “Design Rim” prescribed in TRA, or “Measuring Rim” prescribed in ETRTO. The specified internal pressure means “maximum air pressure” defined by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO. The specified load means the “maximum load capacity” defined by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “LOAD CAPACITY” defined by ETRTO. However, in JATMA, in the case of tires for passenger cars, the specified internal pressure is air pressure 180 [kPa], and the specified load is 88 [%] of the maximum load capacity.

  The circumferential main grooves 21 and 22 may have a straight shape, or may have a zigzag shape or a wavy shape. For example, in the configuration of FIG. 3, the circumferential main groove 21 on the tire equatorial plane CL has a zigzag shape formed by alternately connecting long portions and short portions having different inclination angles in the tire circumferential direction. Have. The left and right outermost circumferential main grooves 22, 22 have a straight shape.

  Moreover, it is preferable that the groove width W1 of the circumferential main groove 21 closest to the tire equatorial plane CL and the tread width TW have a relationship of 0.05 ≦ W1 / TW ≦ 0.09. Moreover, it is preferable that the groove width W2 of the outermost circumferential main groove 22 and the tread width TW have a relationship of 0.06 ≦ W2 / TW ≦ 0.10. As a result, the groove widths W1 and W2 of the circumferential main grooves 21 and 22 are optimized.

  The circumferential main groove 21 closest to the tire equatorial plane CL corresponds to the circumferential main groove 21 in the configuration having the circumferential main groove 21 on the tire equatorial plane CL (see FIG. 3). In the configuration having a land portion on the top (not shown), the circumferential main groove 21 closer to the tire equatorial plane CL among the left and right circumferential main grooves defining the land portion corresponds.

  In the configuration of FIG. 3, the three circumferential main grooves 21 and 22 are arranged symmetrically about the tire equatorial plane CL. Thus, in the configuration in which the plurality of circumferential main grooves 21 and 22 are arranged symmetrically with respect to the tire equatorial plane CL as a boundary, the wear forms in the left and right regions with the tire equatorial plane CL as a boundary are uniformed, This is preferable in that the wear life of the tire is improved.

  However, the present invention is not limited thereto, and the circumferential main grooves 21 and 22 may be arranged asymmetrically about the tire equatorial plane CL (not shown). Further, the circumferential main groove 21 may be disposed at a position deviated from the tire equatorial plane CL (not shown).

  In the configuration of FIG. 3, four rows of land portions 31 and 32 are partitioned by the three circumferential main grooves 21 and 22. Further, the circumferential main groove 21 is disposed on the tire equatorial plane CL.

  However, the present invention is not limited to this, and four or more circumferential main grooves may be arranged (not shown). For this reason, the land part 31 may be arrange | positioned on the tire equator surface CL.

[Circular narrow groove and lug groove in the center land]
In the configuration of FIG. 3, the land portion 31 on the inner side in the tire width direction adjacent to the outermost circumferential main groove 22 includes one circumferential narrow groove 311 and a plurality of lug grooves 312. Further, the retread tire 10 has a point-symmetric tread pattern, and the land portion 31 on the inner side in the tire width direction adjacent to the left and right outermost circumferential main grooves 22 has one circumferential narrow groove 311 and a plurality of lug grooves 312. Each has. Thereby, the rib rigidity of the land part 31 is optimized and the partial wear of the land part 31 is reduced.

  Further, the circumferential narrow groove 311 extends continuously over the entire circumference of the tire. The circumferential narrow groove 311 may have a straight shape, or may have a zigzag shape or a wavy shape. For example, in the configuration of FIG. 3, the circumferential narrow groove 311 has a zigzag shape formed by alternately connecting long portions and short portions having different inclination angles in the tire circumferential direction. Further, the circumferential narrow groove 311 has a wide structure in which the groove width is widened at the short portion. Moreover, the circumferential direction narrow groove 311 is arrange | positioned in the approximate center area | region of the land part 31, and has divided the land part 31 in the tire width direction.

  The groove width of the circumferential narrow groove 311 is in the range of 1.5 [mm] to 4.5 [mm]. The groove depth of the circumferential narrow groove 311 is preferably in the range of 10 [%] to 40 [%] with respect to the groove depth of the outermost circumferential main groove 22, and is 20 [%] or more. More preferably, it is in the range of 30 [%] or less. In other words, the circumferential narrow groove 311 is preferably a shallow groove. Thereby, the rigidity of the land part 31 is ensured and uneven wear of the tire is suppressed.

  In the configuration of FIG. 3, as described above, the retreaded tire 10 includes the three circumferential main grooves 21 and 22 and the four rows of land portions 31 and 32. For this reason, the land portion 31 on the inner side in the tire width direction adjacent to the outermost circumferential main groove 22 is also adjacent to the tire equatorial plane CL, and the circumferential narrow groove 311 and the lug groove 312 are arranged on the land portion 31. ing.

  On the other hand, in a configuration including five or more rows of land portions (not shown), at least a land portion (so-called second land portion) on the inner side in the tire width direction adjacent to the outermost circumferential main groove 22 is a circumferential narrow groove 311 and a lug. A groove 312 may be provided.

  In the configuration of FIG. 3, the land portions 31, 31 on the inner side in the tire width direction adjacent to the left and right outermost circumferential main grooves 22, 22 are each provided with a plurality of lug grooves 312. A plurality of lug grooves 312 are arranged at predetermined intervals in the tire circumferential direction. Further, the lug groove 312 extends while inclining at a predetermined angle in the tire width direction, and connects the circumferential narrow groove 311 and the outermost circumferential main groove 22. Therefore, a portion of the land portion 31 that is divided into the circumferential narrow groove 311 and the outermost circumferential main groove 22 is divided into a block row by the plurality of lug grooves 312 in the tire circumferential direction. The circumferential narrow groove 311 has a zigzag shape, and the lug groove 312 is connected to the zigzag bent portion of the circumferential narrow groove 311. In addition, the lug groove 312 widens the groove width at both the connecting portion with the circumferential narrow groove 311 and the connecting portion with the outermost circumferential main groove 22.

  Further, the lug groove 312 terminates at the connecting portion with the circumferential narrow groove 311 without penetrating the circumferential narrow groove 311 in the tire width direction. For this reason, the area | region inside the tire width direction of the circumferential direction narrow groove 311 in the land part 31 is a rib which continues in a tire circumferential direction. In such a configuration, the rigidity of the land portion 31 on the tire equatorial plane CL side is ensured, and uneven wear in the tread portion center region is suppressed.

  The groove width of the lug groove 312 is in the range of 1.0 [mm] to 4.0 [mm]. The groove depth of the lug groove 312 is preferably in the range of 10 [%] to 0.40 [%] with respect to the groove depth of the outermost circumferential main groove 22, and is 20 [%] to 30 [ %] Is more preferably in the following range. That is, the lug groove 312 is preferably a shallow groove. Thereby, the rigidity of the land part 31 is ensured and uneven wear of the tire is suppressed.

  Moreover, short and a plurality of sipes (so-called multi-sipe, not shown) are disposed at predetermined intervals in the tire circumferential direction at the left and right edge portions of the land portion 31 facing the circumferential main grooves 21 and 22. Thereby, the ground pressure of the edge part of the land part 31 is disperse | distributed, and uneven wear is suppressed.

[Notch of shoulder land]
In the configuration of FIG. 3, the shoulder land portion 32 includes a plurality of notches 321 at the edge portion on the outermost circumferential main groove 22 side.

  Further, the cutout portions 321 have a trapezoidal shape in a plan view of the tread, and are arranged at a ratio of one to one pitch of the tread pattern. In addition, a plurality of sets of cutout portions 321 and lug grooves 312 of the center land portion 31 are alternately arranged in one outermost circumferential main groove 22 while being offset in the tire circumferential direction. For this reason, the notches 321 and the lug grooves 312 are arranged in the tire circumferential direction so that the rigidity of the left and right edge portions of the outermost circumferential main groove 22 is made uniform in the tire circumferential direction. Thereby, the partial wear of a tire is suppressed.

  Further, a short and a plurality of sipes (so-called multi-sipe, not shown) are arranged at predetermined intervals in the tire circumferential direction at the edge portion of the shoulder land portion 32 on the outermost circumferential main groove 22 side. Thereby, the ground pressure of the edge part of the land part 31 is disperse | distributed, and the partial wear of the shoulder land part 32 is suppressed.

[Groove wall angle of circumferential main groove]
4 and 5 are enlarged views showing a main part of the retread tire described in FIG. In these drawings, FIG. 4 shows a cross-sectional view in the tire meridian direction of a one-side region defined as a tire equatorial plane CL. FIG. 5 shows an enlarged cross-sectional view of the circumferential main grooves 21 and 22.

  In this rehabilitated tire 10, as shown in FIG. 4, a distance Le from the tire equatorial plane CL to the edge portion of the land portion (shoulder land portion) 32 on the outer side in the tire width direction defined in the outermost circumferential main groove 22; The distance Lh from the tire equatorial plane CL to the end of the narrow cross belt 142 has a relationship of 0.60 ≦ Le / Lh ≦ 0.85. That is, the edge portion of the shoulder land portion 32 is arranged at a predetermined distance Lh-Le on the inner side in the tire width direction with respect to the narrow cross belt 142. Thereby, the rigidity of the shoulder land portion 32 is appropriately secured, and uneven wear of the shoulder land portion 32 is suppressed.

  The distance Le of the edge portion of the outermost circumferential main groove 22 is based on the edge portion on the outermost circumferential main groove 22 side on the tread surface of the land portion in a no-load state in which the tire is mounted on the prescribed rim and filled with the prescribed internal pressure. As measured. Further, in a configuration in which the land portion has a notch portion or a chamfered portion at the edge portion, the distance Le is measured based on the intersection point between the tread surface of the land portion and the extension line of the groove wall of the outermost circumferential main groove 22.

  The distance Lh between the ends of the narrow cross belt 142 is the outermost in the tire width direction of the belt cords constituting the belt layer in a no-load state in which the tire is mounted on the specified rim and filled with the specified internal pressure. Measured with reference to belt cord.

  In the configuration of FIG. 4, the narrow cross belt 142 is arranged on the outer side in the radial direction than the wide cross belt 141. On the other hand, even when the narrow cross belt 142 is disposed radially inward of the wide cross belt 141, the distance Lh is measured with the narrow cross belt 142 as a reference. Further, in a configuration in which the cross belt is composed of three or more belt plies (not shown), the distance Lh is measured with the narrowest cross belt as a reference.

  As shown in FIG. 5, the groove wall angle θc of the circumferential main groove 21 closest to the tire equatorial plane CL and the groove wall angle θs of the outermost circumferential main groove 22 have a relationship of θc ≦ θs. The difference θs−θc between the groove wall angles θc and θs is preferably in the range of 1 [deg] ≦ θs−θc, and preferably in the range of 3 [deg] ≦ θs−θc ≦ 10 [deg]. More preferred. The groove wall angle θs of the outermost circumferential main groove 22 is preferably in the range of 6 [deg] ≦ θs ≦ 16 [deg]. Thereby, the groove wall angle θs of the outermost circumferential main groove 22 is secured, and the rigidity of the shoulder land portion 32 is secured.

  The groove wall angles θc, θs are straight lines perpendicular to the tread surface of the land portion through the edge portion of the land portion in a sectional view in the tire meridian direction in a no-load state in which the tire is mounted on the specified rim and filled with the specified internal pressure. , Measured as the angle between the groove wall surface. At this time, for example, the following measuring method is used. First, a single tire is applied to a virtual line of a tire profile measured by a laser profiler and fixed with tape or the like. And it measures with a caliper etc. about the gauge which is a measuring object. The laser profiler is, for example, a tire profile measuring device (manufactured by Matsuo Corporation). In addition, in the configuration where the land portion has a chamfered portion at the edge portion, an imaginary line extending the tread surface of the land portion and an imaginary line extending the groove wall surface are taken, passing through this intersection point and perpendicular to the tread surface of the land portion. The angle formed between the straight line and the groove wall surface is the groove wall angle.

  In the configuration of FIG. 3, as described above, the three circumferential main grooves 21 and 22 and the four rows of land portions 31 and 32 are arranged symmetrically about the tire equatorial plane CL. . The groove wall angle θc of the circumferential main groove 21 in the center and the groove wall angle θs of the left and right outermost circumferential main grooves 22 and 22 have the above relationship.

  On the other hand, in a configuration including four or more circumferential main grooves (not shown), the tire equatorial plane is the groove wall angle θs of the left and right outermost circumferential main grooves 22 and 22 among the plurality of circumferential main grooves at the center. It is sufficient to have the above relationship with respect to the groove wall angle θc of the circumferential main groove 21 closest to CL. Moreover, it is preferable that the groove wall angle θs of the left and right outermost circumferential main grooves 22, 22 has the above relationship with the groove wall angles θc of all other circumferential main grooves 21.

[Groove area ratio]
In the configuration of FIG. 3, the groove area ratio A of the entire tread pattern is preferably in the range of 0.20 ≦ A ≦ 0.35. Thereby, the groove area ratio A is optimized and the contact pressure at the time of tire contact is optimized.

  The groove area ratio A of the entire tread pattern is defined by groove area / (groove area + ground area). The groove area refers to the opening area of the groove on the ground contact surface. Further, the groove refers to a circumferential groove and a lug groove in the tread portion, and does not include sipes, kerfs, and notches. The ground contact area is the contact area between the tire and the road surface. In addition, the groove area and the contact area are determined when the tire is mounted on the specified rim and applied with the specified internal pressure, and is placed perpendicular to the flat plate in a stationary state and applied with a load corresponding to the specified load. Measured at the contact surface between the plate and the flat plate.

  3, the groove area ratio Ac of the land portion 31 on the inner side in the tire width direction adjacent to the outermost circumferential main groove 22 and the groove area ratio As of the land portion 32 on the outer side in the tire width direction are 1.5 ≦. It is preferable to be in the range of Ac / As. The ratio Ac / As is more preferably in the range of 2.5 ≦ Ac / As ≦ 4.5. Thereby, the relationship between the groove area ratios Ac and As of the left and right land portions 31 and 32 adjacent to the outermost circumferential main groove 22 is optimized, and in particular, uneven wear of the shoulder land portion 32 is suppressed.

  The groove area ratios Ac and As of the land portions 31 and 32 are defined in the same manner as the groove area ratio A of the entire tread pattern described above. However, the groove area of the land portion is measured as the sum of the areas of grooves formed in the land portion itself (for example, lug grooves, narrow grooves, etc.). Areas such as formed sipes, kerfs, and notches are excluded from the land area.

[Carcass layer and belt layer]
Moreover, the retread tire 10 is provided with the carcass layer 13 and the belt layer 14 arrange | positioned on the tire radial direction outer side of the carcass layer 13 as mentioned above (refer FIG. 1).

  For example, in the retread tire 10 for a light truck shown in FIG. 1, the carcass layer 13 and the belt layer 14 are included in the base tire 30. Further, the carcass layer 13 is bridged in a toroidal shape between the pair of left and right bead cores 11 and 11 to constitute a tire skeleton. Further, both end portions of the carcass layer 13 are wound and locked outward in the tire width direction so as to wrap the bead core 11 and the bead filler 12. The carcass layer 13 is formed by rolling a plurality of carcass cords made of steel or an organic fiber material (for example, aramid, nylon, polyester, rayon, etc.) with a coat rubber, and has an absolute value of 80 [deg]. A carcass angle of 95 [deg] or less (inclination angle in the fiber direction of the carcass cord with respect to the tire circumferential direction) is obtained.

  The belt layer 14 is formed by laminating a pair of cross belts 141 and 142 and a belt cover 143, and is arranged so as to be wound around the outer periphery of the carcass layer 13.

  The pair of cross belts 141 and 142 is formed by rolling a plurality of belt cords made of steel or organic fiber material with a coating rubber, and is an absolute value of 10 [deg] or more and 55 [deg] or less. Have an angle. Further, the pair of cross belts 141 and 142 have belt angles of different signs (inclination angles in the fiber direction of the belt cord with respect to the tire circumferential direction) and are laminated so that the fiber directions of the belt cords cross each other. Yes (cross-ply structure). Note that three or more cross belts may be laminated (not shown).

  The belt cover 143 is formed by rolling a plurality of cords made of steel or organic fiber material covered with a coat rubber. The belt cover 143 preferably has an absolute value of a belt angle of 0 [deg] or more and 10 [deg] or less, and more preferably a belt angle of 0 [deg] or more and 5 [deg] or less. A belt cover 143 is disposed so as to be laminated on the outer side in the tire radial direction of the cross belts 141 and 142.

  1, the belt width Wb1 of the wide cross belt 141 and the carcass cross-sectional width Wa of the carcass layer 13 preferably have a relationship of 0.65 ≦ Wb1 / Wa ≦ 0.90. .68 ≦ Wb1 / Wa ≦ 0.80 is more preferable. Thereby, ratio Wb1 / Wa is optimized and the riding comfort of a tire improves.

  The carcass cross-sectional width Wa is a distance in the tire width direction at the left and right maximum width positions of the carcass layer 13, and is measured as a no-load state while attaching a tire to a specified rim and applying a specified internal pressure.

  Moreover, it is preferable that the belt width Wb1 of the wide cross belt 141 and the tread width TW have a range of 0.70 ≦ Wb1 / TW ≦ 1.00.

  Further, the belt width Wb2 of the narrow cross belt 142 and the tread width TW preferably have a range of 0.70 ≦ Wb2 / TW ≦ 0.95, and 0.80 ≦ Wb2 / TW ≦ 0.90. It is more preferable to have this range.

  The belt widths Wb1 and Wb2 are distances in the tire width direction of the belt cords on the outermost side in the tire width direction in a cross sectional view in the tire meridian direction. As measured.

[Belt cover]
Moreover, in this retreaded tire 10, in FIG. 1, the distance Wc between the left and right end portions on the outer side in the tire width direction of the belt cover 143 and the tread width TW satisfy 0.75 ≦ Wc / TW ≦ 1.00. It is preferable to have a relationship, and it is more preferable to have a relationship of 0.80 ≦ Wc / TW ≦ 0.90. Thereby, the ground contact shape of the tire is optimized, and the uneven wear resistance performance of the tire is ensured.

  The distance Wc is the distance in the tire width direction of the outermost belt cord in the tire width direction in a cross-sectional view in the tire meridian direction, and is measured as an unloaded condition while attaching the tire to a specified rim and applying a specified internal pressure. The Further, in a configuration (not shown) in which the belt cover 143 is divided in the tire width direction, the distance Wc is measured with reference to the left and right end portions of the belt cover that is the outermost in the tire width direction.

  The number of ends of the belt cover 143 is preferably in the range of 40 [lines / 50 mm] to 60 [lines / 50 mm]. Moreover, it is preferable that the thickness of the thread | yarn which comprises the belt cover 143 exists in the range of 1100 [dtex / 2] or more and 1500 [dtex / 2] or less. As a result, the structure of the belt cover 143 is optimized.

  For example, in the configuration of FIG. 1, the single-layer belt cover 143 has a so-called full cover structure, and extends continuously in the tire width direction so as to cover the entire area of the belt layer 14. Further, the belt cover 143 extends to the end of the wide cross belt 141, thereby covering the ends of the pair of cross belts 141 and 142 at the same time. Further, as shown in FIG. 4, an additional belt cover 144 is laminated on the outer side in the tire radial direction of the belt cover 143. The additional belt cover 144 is partially disposed at a position covering the left and right ends of the pair of cross belts 141 and 142 and functions as a so-called edge cover. For this reason, a plurality of belt covers 143 and 144 are disposed at the left and right ends of the cross belts 141 and 142, respectively, and the number of stacked belt covers is greater than the position where the belt equatorial plane CL intersects. . Thereby, the restraining force with respect to the edge part of the cross belts 141 and 142 is heightened.

  However, the present invention is not limited to this, and a plurality of belt covers 143 having a full cover structure may be laminated so as to cover the entire belt layer 14 (not shown). Therefore, the belt cover 143 may have a multilayer structure. Further, a belt ply may be further arranged outside the belt cover 143 in the tire radial direction (not shown). Therefore, the belt cover 143 may not be disposed on the outermost layer of the belt layer 14.

[Tread rubber gauge]
In FIG. 4, the relationship between the tread gauge Dcc on the tire equatorial plane CL and the tread gauge De at the outer end in the tire width direction of the narrow cross belt 142 is 1.03 ≦ Dcc / De ≦ 1.20. It is preferable to have 1.05 ≦ Dcc / De ≦ 1.10. Thereby, the ratio Dcc / De is optimized.

  The tread gauge Dcc is a belt of a belt ply (belt cover 143 in FIG. 4) at the intersection of the tire equatorial plane CL and the tread profile and the outermost radial direction of the belt layer 14 in a sectional view in the tire meridian direction. Measured as the distance to the code surface. The belt cord surface is defined as a surface including ends of the plurality of belt cords constituting the belt ply on the outer side in the tire radial direction.

  The tread gauge De is measured as the thickness of the tread rubber on the perpendicular drawn from the end of the narrow cross belt 142 to the tread surface in a cross-sectional view in the tire meridian direction. The end portion of the cross belt 142 refers to the end surface of the belt cord that is the outermost in the tire width direction among the belt cords constituting the cross belt 142.

  In FIG. 4, the tread gauge Dcc on the tire equatorial plane CL and the tread gauge Dsh from the outer end in the tire width direction of the belt cover 143 to the tread end T are 1.00 ≦ Dsh / Dcc ≦ 1.70. It is preferable to have a relationship of 1.20 ≦ Dsh / Dcc ≦ 1.40, and more preferable. Thereby, Dsh / Dcc is optimized.

  The tread gauge Dsh is measured on the basis of the end surface of the belt cord that is the outermost in the tire width direction among the belt cords constituting the belt cover 143 in a sectional view in the tire meridian direction.

  Further, in FIG. 5, the new rubber sub-groove gauge Ga1 of the circumferential main groove 21 closest to the tire equatorial plane CL is preferably in the range of 1.0 [mm] ≦ Ga1 ≦ 5.0 [mm] More preferably, the range is 2.0 [mm] ≦ Ga1 ≦ 3.0 [mm]. Thereby, the new under-groove groove gauge Ga1 of the circumferential main groove 21 in the center region of the tread portion is optimized.

  In FIG. 5, the new rubber sub-groove gauge Ga2 of the outermost circumferential main groove 22 has a relationship of Ga2 <Ga1 with respect to the new rubber sub-groove gauge Ga1 of the circumferential main groove 21 closest to the tire equatorial plane CL. It is preferable to have. Therefore, the new under-groove groove gauge Ga2 of the circumferential main groove 22 in the tread portion shoulder region is smaller than the new under-groove gauge Ga1 of the circumferential main groove 21 in the tread portion center region.

  Further, the new sub-groove gauge Ga2 is preferably in the range of 1.0 [mm] ≦ Ga2 ≦ 4.0 [mm], and in the range of 1.3 [mm] ≦ Ga2 ≦ 3.0 [mm]. More preferably. Thereby, the new under-groove groove gauge Ga2 of the circumferential main groove 22 in the tread shoulder region is optimized.

  The new rubber sub-groove gauges Ga1 and Ga2 are sub-groove gauges in the tread 20 newly added by rehabilitation, and are treads from the maximum groove depth position of the circumferential main grooves 21 and 22 in the sectional view in the tire meridian direction. It is measured as the distance to the inner circumferential surface of 20 tire radial directions.

  In FIG. 5, the groove depth D1 of the circumferential main groove 21 closest to the tire equatorial plane CL and the tread gauge Dcc in the tire equatorial plane CL have a relationship of 1.30 ≦ Dcc / D1 ≦ 1.55. Preferably, it has a relationship of 1.40 ≦ Dcc / D1 ≦ 1.50. Thereby, the ratio Dcc / D1 is optimized.

[Modification]
FIG. 6 is an explanatory view showing a modified example of the retread tire described in FIG. 1. This figure shows the profile of the shoulder portion.

  In the configuration of FIG. 1, as shown in FIG. 4, the retread tire 10 includes a shoulder portion having a square shape in a sectional view in the tire meridian direction. In such a configuration, the measurement point of the tread width TW is the edge portion on the outer side in the tire width direction of the shoulder land portion 32.

  However, the present invention is not limited thereto, and the retreaded tire 10 may include a shoulder portion having a round shape (see FIG. 6) or a chamfered shape (not shown) in a sectional view in the tire meridian direction.

  In such a configuration, the measurement point of the tread width TW is the intersection T between the extension line of the ground contact surface of the shoulder land portion 32 and the extension line of the profile of the buttress portion (non-ground region of the shoulder portion) in a sectional view in the tire meridian direction. Defined by '.

  Further, the tread gauge Dsh is a straight line drawn from the intersection T ′ to the end surface of the belt cord that is the outermost in the tire width direction among the belt cords that constitute the belt cover 143 in a sectional view in the tire meridian direction. Measured as the thickness of the tread rubber.

[effect]
As described above, the retread tire 10 includes the tread 20 and the base tire 30 (see FIG. 1). Further, the tread 20 includes at least three circumferential main grooves 21 and 22 extending in the tire circumferential direction and a plurality of land portions 31 and 32 that are partitioned by the circumferential main grooves 21 and 22. Prepare for the surface (see FIG. 3). Further, the base tire 30 includes a carcass layer 13 and a belt layer 14 disposed on the outer side in the tire radial direction of the carcass layer 13. Further, the belt layer 14 includes a pair of cross belts 141 and 142 and a belt cover 143 disposed on the outer side in the tire radial direction of the pair of cross belts 141 and 142. Further, the tread width TW and the tire total width SW have a relationship of 0.65 ≦ TW / SW ≦ 0.85 (see FIG. 1). Further, the distance SDH in the tire radial direction from the rim diameter measurement point P to the tire maximum width position Q and the tire cross-section height SH have a relationship of 0.45 ≦ SDH / SH ≦ 0.65. Further, the distance Le from the tire equatorial plane CL to the edge portion of the land portion 32 on the outer side in the tire width direction defined in the outermost circumferential main groove 22 and the end of the narrow cross belt 142 from the tire equatorial plane CL. The distance Lh has a relationship of 0.60 ≦ Le / Lh ≦ 0.85 (see FIG. 4).

  In such a configuration, since the ratio TW / SW and the ratio SDH / SH that define the profile are optimized, there is an advantage that the ground contact shape of the tire is optimized and the uneven wear resistance performance of the tire is improved. Moreover, the rigidity of the shoulder land portion 32 is appropriately ensured by optimizing the positional relationship (distance Le, Lh) between the edge portion of the shoulder land portion 32 and the end portion of the narrow cross belt 142. Thereby, the uneven wear of the shoulder land portion 32 is particularly suppressed, and there is an advantage that the uneven wear resistance performance of the tire is further improved.

  In this retread tire 10, the groove wall angle θc of the circumferential main groove 21 closest to the tire equatorial plane CL and the groove wall angle θs of the outermost circumferential main groove 22 have a relationship of θc ≦ θs (see FIG. 5). In such a configuration, the groove wall angle θs of the outermost circumferential main groove 22 is optimized, and the rigidity of the shoulder land portion 32 is appropriately ensured. Thereby, the uneven wear of the shoulder land portion 32 is particularly suppressed, and there is an advantage that the uneven wear resistance performance of the tire is improved.

  In this retread tire 10, the groove wall angle θs of the outermost circumferential main groove 22 is in the range of 6 [deg] ≦ θs ≦ 16 [deg] (see FIG. 5). Accordingly, there is an advantage that the groove wall angle θs of the outermost circumferential main groove 22 is optimized. That is, by satisfying 6 [deg] ≦ θs, the rigidity of the shoulder land portion 32 is appropriately secured, and in particular, uneven wear of the shoulder land portion 32 is suppressed. In addition, since θs ≦ 16 [deg], it is possible to suppress the rigidity of the shoulder land portion 32 from being excessive, and in particular, uneven wear of the center land portion 31 is suppressed.

  In this retread tire 10, the groove wall angle θc of the circumferential main groove 21 closest to the tire equatorial plane CL and the groove wall angle θs of the outermost circumferential main groove 22 satisfy 1 [deg] ≦ θs−θc. There is a relationship (see FIG. 5). In such a configuration, the difference θs−θc between the groove wall angles θc and θs of the circumferential main grooves 21 and 22 is optimized, and the rigidity of the shoulder land portion 32 is ensured appropriately. Thereby, there exists an advantage by which the partial wear of the shoulder land part 32 is suppressed especially.

  Moreover, in this retreaded tire 10, the groove area ratio A of the entire tread pattern is in the range of 0.20 ≦ A ≦ 0.35 (see FIG. 3). As a result, there is an advantage that the contact pressure of the entire contact surface at the time of tire contact is optimized, and the uneven wear resistance performance of the tire is ensured.

  Further, in this retreaded tire 10, the groove area ratio Ac of the land portion 31 on the inner side in the tire width direction adjacent to the outermost circumferential main groove 22 and the groove area ratio As of the land portion 32 on the outer side in the tire width direction are 1.5 ≦. It is in the range of Ac / As. Thereby, the relationship between the groove area ratios Ac and As of the left and right land portions 31 and 32 adjacent to the outermost circumferential main groove 22 is optimized, and particularly there is an advantage that uneven wear of the shoulder land portion 32 is suppressed.

  Further, the retread tire 10 has a plurality of circumferential main grooves 21 and 22 extending in the tire circumferential direction and a plurality of land portions 31 and 32 defined by the circumferential main grooves 21 and 22 on the tread surface. Prepare. In addition, the new sub-groove gauge Ga1 of the circumferential main groove 21 closest to the tire equatorial plane CL is in the range of 1.0 [mm] ≦ Ga1 ≦ 5.0 [mm] (see FIG. 5). In such a configuration, there is an advantage that the new under-groove gauge Ga1 of the circumferential main groove 21 in the center region of the tread portion is optimized. That is, by satisfying 1.0 [mm] ≦ Ga1, the new rubber sub-groove gauge Ga1 of the circumferential main groove 21 is secured. Then, since the new rubber of the tread 20 is softer than the old rubber (residual tread 301) of the base tire 30 (the residual tread 301 is deteriorated and hardened), the force acting on the interface between the new rubber and the old rubber is increased. Dispersed to optimize the ground pressure distribution. Thereby, the partial wear-proof performance of a tire is ensured. Further, since Ga1 ≦ 5.0 [mm], the new rubber groove gauge Ga1 of the circumferential main groove 21 is prevented from being excessive, and the contact pressure distribution is optimized. Thereby, the partial wear-proof performance of a tire is ensured.

  Further, in this retreaded tire 10, the new rubber sub-groove gauge Ga2 of the circumferential main groove 22 at the outermost side in the tire width direction satisfies Ga2 <Ga1 and 1.0 [mm] ≦ Ga2 ≦ 4.0 [mm]. It is in range (see FIG. 5). In such a configuration, there is an advantage that the new under-groove gauge Ga2 of the circumferential main groove 22 in the tread shoulder region is optimized. That is, by Ga2 <Ga1, the distortion of the peripheral rubber at the end of the belt layer 14 is reduced, and the ground pressure distribution is optimized. Thereby, the partial wear-proof performance of a tire is ensured. Further, by satisfying 1.0 [mm] ≦ Ga2, the new rubber groove gauge Ga2 of the circumferential main groove 22 is secured. Then, since the new rubber of the tread 20 is softer than the old rubber (residual tread 301) of the base tire 30 (the residual tread 301 is deteriorated and hardened), the force acting on the interface between the new rubber and the old rubber is increased. Dispersed to optimize the ground pressure distribution. Thereby, the partial wear-proof performance of a tire is ensured. Further, since Ga2 ≦ 4.0 [mm], the new rubber groove gauge Ga2 of the circumferential main groove 22 is prevented from becoming excessive, and the ground pressure distribution is optimized. Thereby, the partial wear-proof performance of a tire is ensured.

  Moreover, in this retreaded tire 10, the carcass layer 13 is configured by arranging a plurality of carcass cords made of an organic fiber material. In the retreaded tire 10, the tire life is generally extended by the retreading and the traveling distance is increased. For this reason, in the configuration in which the carcass layer is made of an organic fiber material, the strength of the carcass layer is lowered, the distortion of the peripheral rubber at the end of the cross belt is increased, and the contact pressure distribution in the tire width direction is uneven. Uneven wear tends to occur. Therefore, there is an advantage that the effect of suppressing the uneven wear resistance can be remarkably obtained by using the configuration including the carcass layer 13 made of such an organic fiber material as an application target.

  In this retreaded tire 10, the belt cover 143 is made of an organic fiber material and includes a plurality of cords arranged at an angle of ± 5 [deg] or less with respect to the tire circumferential direction. In the retreaded tire 10, the tire life is generally extended by the retreading and the traveling distance is increased. For this reason, when the belt cover is made of an organic fiber material, the strength of the belt cover decreases, the distortion of the rubber around the end of the cross belt increases, and the contact pressure distribution in the tire width direction becomes uneven. Uneven wear tends to occur. Therefore, there is an advantage that the effect of suppressing the uneven wear resistance can be remarkably obtained by using the configuration including the belt cover 143 made of such an organic fiber material as an application target.

  Further, in this retread tire 10, the single or plural belt covers 143 and 144 cover at least the position intersecting the tire equatorial plane CL and the ends of the pair of intersecting belts 141 and 142 on the outer side in the tire width direction. (See FIGS. 1 and 4). In such a configuration, the belt cover 143 covers the position intersecting the tire equator plane CL, thereby suppressing the diameter growth of the tread portion center region. Thereby, the profile from the tire equatorial plane CL to the shoulder portion becomes flat, and the ground contact shape is made uniform. Further, the belt cover 143 covers the ends of the pair of cross belts 141 and 142 on the outer side in the tire width direction, so that the amount of displacement of the ends of the cross belts 141 and 142 is reduced and the contact shape is made uniform. . Thus, there is an advantage that uneven wear is effectively suppressed.

  Further, in this retreaded tire 10, the tread gauge Dcc on the tire equatorial plane CL and the tread gauge De at the outer end in the tire width direction of the narrow cross belt 142 are 1.03 ≦ Dcc / De ≦ 1.20. (See FIG. 4). Thereby, there exists an advantage by which ratio Dcc / De is optimized. That is, by satisfying 1.03 ≦ Dcc / De, the tread gauge Dcc in the tread portion center region is set larger than the tread gauge De in the shoulder region. Then, since the belt ply is arranged horizontally with respect to the tire ground contact surface, the tension acting on the belt ply is uniformized when the tire is grounded, and the ground pressure distribution is optimized. In addition, since Dcc / De ≦ 1.20 prevents the tread gauge Dcc in the center region from becoming excessive, the amount of displacement of the end portions of the cross belts 141 and 142 when the tire contacts the ground is reduced. The ground pressure distribution is optimized. Thereby, there exists an advantage by which uneven wear is suppressed effectively.

  Further, in this retreaded tire 10, the belt width Wb1 of the wide cross belt 141 and the carcass cross-sectional width Wa of the carcass layer 13 have a relationship of 0.65 ≦ Wb1 / Wa ≦ 0.90 (see FIG. 1). . Thereby, there exists an advantage by which ratio Wb1 / Wa is optimized. That is, by satisfying 0.65 ≦ Wb1 / Wa, the belt width Wb1 is secured, and the distortion of the peripheral rubber at the outer end in the tire width direction of the belt layer 14 is reduced. Thereby, there is an advantage that the ground pressure distribution is optimized and uneven wear is suppressed. Further, since Wb1 / Wa ≦ 0.90 ensures the distance between the end portion of the belt ply and the sidewall portion, movement of the end portion of the belt ply during tire rolling is suppressed. Thereby, there is an advantage that the ground pressure distribution is optimized and uneven wear is suppressed.

  In this retread tire 10, the number of ends of the belt cover 143 is in the range of 40 [lines / 50 mm] to 60 [lines / 50 mm]. Thereby, there exists an advantage by which the number of ends of the belt cover 143 is optimized.

  Moreover, in this retreaded tire 10, the thickness of the thread | yarn which comprises the belt cover 143 exists in the range of 1100 [dtex / 2] or more and 1500 [dtex / 2] or less. Thereby, there exists an advantage by which the thickness of the thread | yarn of the belt cover 143 is optimized.

[Applicable to]
Further, the retread tire 10 is applied to a low flat tire having a flat rate of 70% or less, and particularly to a light truck tire defined by JATMA. In such a low-profile tire for a small truck, the ground contact state of the tread portion is likely to change between when the load is loaded and when the load is not loaded. That is, the center area and the shoulder area of the tread portion are uniformly grounded when loading a load, but the diameter growth of the center area of the tread portion becomes obvious and the contact area of the tread portion shoulder area tends to decrease when no load is loaded. It is in. Then, the repeated strain at the end of the belt layer becomes large, the contact pressure distribution becomes uneven, and uneven wear tends to occur. Therefore, there is an advantage that the effect of suppressing uneven wear can be remarkably obtained by using such a low flat tire for a small truck.

  7 and 8 are charts showing the results of performance tests of the retread tire according to the embodiment of the present invention.

  In this performance test, evaluation on uneven wear resistance performance was performed for a plurality of types of test tires. Further, a test tire having a tire size of 205 / 70R16 111/109 LT is assembled to an applicable rim defined by JATMA, and the highest air pressure and maximum load specified by JATMA are applied to the test tire. In addition, the test tire is mounted on a 3 [t] truck as a test vehicle, and the test vehicle travels on a general pavement road at 50,000 [km] at an average speed of 60 [km / h]. Thereafter, uneven wear occurring in the land is observed, and index evaluation is performed with the conventional example as a reference (100). This evaluation is preferable as the numerical value increases.

  The test tires of Examples 1 to 25 have the structures described in FIGS. 1 and 3 to 5. The tire total width SW is SW = 204 [mm], and the tire cross-section height SH is SH = 143.7 [mm]. Further, the groove width W2 (FIG. 3) of the outermost circumferential main groove 22 is 13.0 [mm], and the groove depth D2 (FIG. 5) is 10.0 [mm]. Further, the tread gauge Dcc on the tire equatorial plane CL is Dcc = 13.7 [mm]. Further, the belt width Wb1 of the wide cross belt 141 is Wb1 = 150 [mm].

  The test tire of the conventional example does not include the belt cover 143 in the configuration of FIG. The test tire of the comparative example has the structure described in FIGS. 1 and 3 to 5.

  As the test results show, the test tires of Examples 1 to 25 show that the uneven wear resistance performance of the tire is improved.

  10: retread tire, 11: bead core, 12: bead filler, 13: carcass layer, 14: belt layer, 141, 142: cross belt, 143, 144: belt cover, 15: tread rubber, 16: sidewall rubber, 17 : Rim cushion rubber, 20: tread, 30: tire, 301: residual tread, 21, 22: circumferential main groove, 31, 32: land portion, 311: circumferential narrow groove, 312: lug groove, 321: notch Part

Claims (16)

It has a tread and a base tire,
The tread includes, on the tread surface, at least three circumferential main grooves extending in the tire circumferential direction and a plurality of land portions defined by the circumferential main grooves, and
The base tire includes a carcass layer and a belt layer disposed on the outer side in the tire radial direction of the carcass layer, and the belt layer is disposed on the outer side in the tire radial direction of the pair of cross belts and the pair of cross belts. A retread tire having a belt cover disposed thereon,
When the circumferential main groove on the outermost side in the tire width direction is called the outermost circumferential main groove,
The tread width TW and the tire total width SW have a relationship of 0.65 ≦ TW / SW ≦ 0.85,
The distance SDH in the tire radial direction from the measurement point of the rim diameter to the tire maximum width position and the tire cross-section height SH have a relationship of 0.45 ≦ SDH / SH ≦ 0.65,
A distance Le from the tire equator plane to the edge portion of the land portion on the outer side in the tire width direction defined in the outermost circumferential main groove, and a distance Lh from the tire equator plane to the end of the narrow cross belt A retread tire having a relationship of 0.60 ≦ Le / Lh ≦ 0.85.   2. The retread tire according to claim 1, wherein the groove wall angle θc of the circumferential main groove closest to the tire equatorial plane and the groove wall angle θs of the outermost circumferential main groove have a relationship of θc ≦ θs.   The retreaded tire according to claim 1 or 2, wherein a groove wall angle θs of the outermost circumferential main groove is in a range of 6 [deg] ≦ θs ≦ 16 [deg].   The groove wall angle θc of the circumferential main groove closest to the tire equatorial plane and the groove wall angle θs of the outermost circumferential main groove have a relationship of 1 [deg] ≦ θs−θc. Rehabilitation tire given in any 1 paragraph.   The retreaded tire according to any one of claims 1 to 4, wherein a groove area ratio A of the entire tread pattern is in a range of 0.20≤A≤0.35.   The groove area ratio Ac of the land portion inside the tire width direction adjacent to the outermost circumferential main groove and the groove area ratio As of the land portion outside the tire width direction are in a range of 1.5 ≦ Ac / As. Item 6. The retread tire according to any one of Items 1 to 5.   The new rubber sub-groove gauge Ga1 of the circumferential main groove closest to the tire equatorial plane is in the range of 1.0 [mm] ≦ Ga1 ≦ 5.0 [mm]. The rehabilitated tire described.   The retreaded tire according to claim 7, wherein the new rubber sub-groove gauge Ga2 of the outermost circumferential main groove is in a range of Ga2 <Ga1 and 1.0 [mm] ≦ Ga2 ≦ 4.0 [mm].   The retread tire according to any one of claims 1 to 8, wherein the carcass layer is configured by arranging a plurality of carcass cords made of an organic fiber material.   The rehabilitation according to any one of claims 1 to 9, wherein the belt cover is made of an organic fiber material and includes a plurality of cords arranged at an angle of ± 5 [deg] or less with respect to a tire circumferential direction. tire.   The single or plural belt covers are disposed so as to cover at least a position intersecting the tire equatorial plane and an end portion on the outer side in the tire width direction of the pair of intersecting belts. Rehabilitation tire as described in.   The tread gauge Dcc on the tire equator plane and the tread gauge De at the outer end in the tire width direction of the narrow cross belt have a relationship of 1.03 ≦ Dcc / De ≦ 1.20. The retreaded tire as described in any one of these.   The belt width Wb1 of the wide intersecting belt and the carcass cross-sectional width Wa of the carcass layer have a relationship of 0.65 ≦ Wb1 / Wa ≦ 0.90. Rehabilitation tire.   The retreaded tire according to any one of claims 1 to 13, wherein the number of ends of the belt cover is in a range of 40 [lines / 50mm] to 60 [lines / 50mm].   The rehabilitated tire according to any one of claims 1 to 14, wherein a thickness of a thread constituting the belt cover is in a range of 1100 [dtex / 2] to 1500 [dtex / 2].   The retreaded tire according to any one of claims 1 to 15, which has a flatness ratio of 70% or less.

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