JP6369184B2 - Rehabilitation tire - Google Patents

Description

  The present invention relates to a retreaded tire, and more particularly to a retreaded tire that can improve the durability 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

  Therefore, the present invention has been made in view of the above, and an object thereof is to provide a retread tire that can improve the durability 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 base tire is disposed on the outer side in the tire radial direction of the carcass layer and the carcass layer. A retread tire having a belt, and a tread width TW and a tire total width SW in a cross-sectional view in the tire meridian direction when the tire is mounted on a specified rim and applied with a specified internal pressure and in a no-load state. Has a relationship of 0.65 ≦ TW / SW ≦ 0.90, and 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 are 0.45. ≦ SDH / SH ≦ 0.65, the leg of the perpendicular line L1 drawn from the point E of the cross belt on the outer side in the tire radial direction to the tread profile is defined as a point R1, and the perpendicular line L1 passes through the point E. Perpendicular to When the intersection of the straight line L2 and the profile of the buttress portion is a point S1, the distance A1 from the point E to the point R1 and the distance B1 from the point E to the point S1 are 0.90 ≦ B1 / A1 ≦ 1. .50 relationship.

  In the retreaded tire according to the present invention, the profile from the tire equatorial plane to the shoulder becomes flat when the ratio TW / SW and the ratio SDH / SH are optimized. Then, the deformation amount of the tread portion at the time of tire rolling is reduced, the separation of the peripheral rubber at the edge portion of the cross belt is suppressed, and the heat generation of the tread rubber in the tread portion shoulder region is suppressed. In addition, by adjusting the ratio B1 / A1, the volume of the tread rubber around the edge portion of the cross belt is optimized. By these, there exists an advantage which the durable performance of a tire improves.

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 an explanatory view showing a main part of the retread tire shown in FIG. FIG. 4 is an explanatory view showing a main part of the retread tire shown in FIG. FIG. 5 is an explanatory view showing a main part of the retread tire shown in FIG. FIG. 6 is an explanatory view showing a modified example of the retread tire described in FIG. 1. FIG. 7 is an explanatory view showing a modified example of the retread tire described in FIG. 1. 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. In addition, the land portion 31 on the inner side in the tire width direction defined by the outermost circumferential main groove is called a center land portion, and the land portion 32 on the outer side in the tire width direction is called 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.

  Since the retreaded tire uses a tire whose remaining groove has reached the end of its life as a base tire, an old rubber (residual tread) that has deteriorated and becomes hard exists in the lower layer of the new rubber. For this reason, compared with a new tire, the request | requirement which should improve the durable performance of a tire is strong.

  Accordingly, the retread tire 10 employs the following configuration in order to improve the durability performance particularly in a light 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 ≦ 0.90. 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.

  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.

  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. Then, the amount of deformation of the tread portion at the time of tire rolling is reduced, the separation of the peripheral rubber at the edge portions of the cross belts 141 and 142 is suppressed, and the heat generation of the tread rubber in the tread portion shoulder region is suppressed. Thereby, the durability performance of a tire improves.

[Rubber gauge in the shoulder area of the tread]
3 and 4 are explanatory views showing a main part of the retread tire described in FIG. In these drawings, FIG. 3 shows a cross-sectional view in the tire meridian direction of one side region with the tire equatorial plane CL as a boundary, and FIG. 4 shows an enlarged cross-sectional view of a tread portion shoulder region.

  As shown in FIG. 4, the edge of the cross belt 142 on the outer side in the tire radial direction in a cross-sectional view in the tire meridian direction when the tire is mounted on the specified rim to apply the specified internal pressure and is in a no-load state. A leg of a perpendicular line L1 drawn from the point E to the tread profile is defined as a point R1. Further, an intersection of the straight line L2 passing through the point E and perpendicular to the perpendicular line L1 and the profile of the buttress portion is defined as a point S1.

  At this time, in this retreaded tire 10, the distance A1 from the point E to the point R1 and the distance B1 from the point E to the point S1 have a relationship of 0.90 ≦ B1 / A1 ≦ 1.50. The ratio B1 / A1 preferably has a relationship of 1.15 ≦ B1 / A1 ≦ 1.35.

  The point E at the edge of the cross belt 142 is defined by the outermost belt cord in the tire width direction constituting the cross belt 142.

  The buttress portion is a non-grounding region formed at a connection portion between the profile of the tread portion and the profile of the sidewall portion, and constitutes the side wall surface of the shoulder land portion 32 on the outer side in the tire width direction.

  In the above configuration, the ratio B1 / A1 is optimized, so that the volume of the tread rubber around the edge portion of the cross belt 142 is optimized. Thereby, the heat generation of the tread rubber in the tread portion shoulder region is suppressed, and the durability performance of the tire is improved.

  Further, as shown in FIG. 4, the measurement point of the tread width TW and the tire of the tread 20 in a cross-sectional view in the tire meridian direction when the tire is attached to the specified rim to apply the specified internal pressure and the unloaded state is applied. An imaginary line L3 connecting the point U at the end on the outer side in the width direction and the inner side in the tire radial direction is drawn.

  In FIG. 4, since the tread 20 has a square shape, the tire ground contact edge T and the tread edge coincide with each other, and the tire ground contact edge T is a measurement point of the tread width TW. Further, in FIG. 4, the point U is an edge portion on the outer side in the tire width direction and on the inner side in the tire radial direction of the tread 20 that is a new rubber.

  At this time, it is preferable that the profile in the region from the measurement point of the tread width TW to the point U is closer to the tire lumen than the virtual line L3. Thereby, the volume of the tread rubber is reduced, and the heat generation of the tread rubber in the tread portion shoulder region is effectively suppressed.

  For example, in the configuration of FIG. 4, the tread 20 has a square shape in a cross-sectional view in the tire meridian direction, and the buttress portion (non-grounding region) has a substantially arc shape that is recessed toward the tire lumen portion. ing. For this reason, the buttress portion has a so-called reverse profile and does not protrude outside the tire. Thereby, the volume of the tread 20 which is a new rubber is reduced.

  Further, as shown in FIG. 4, the inner peripheral surface of the tread 20, the perpendicular L <b> 1, and the straight line in a cross-sectional view in the tire meridian direction when the tire is attached to the specified rim to apply the specified internal pressure and is in a no-load state. Let the intersections with L2 be R2 and S2.

  At this time, the distance A2 from the point R1 to the point R2 and the distance B2 from the point S1 to the point S2 preferably have a relationship of 0.30 ≦ B2 / A2 ≦ 0.60, and 0.40 ≦ B2 More preferably, it is in the range of /A2≦0.50. Thereby, the volume of the peripheral rubber in the edge part of the cross belt 142 is optimized.

  The inner peripheral surface of the tread 20 is an adhesive surface for the base tire 30 (residual tread 301).

  In FIG. 4, the distance B2 is preferably in the range of 5.0 [mm] ≦ B2. Thereby, the new rubber gauge in the periphery of the edge part of the cross belt 142 is ensured appropriately. The upper limit of the distance B2 is not particularly limited, but is limited by the relationship with the tread profile and the virtual line L3.

[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, the ratio Wb1 / Wa is optimized.

  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 a tire is optimized.

  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. 3, 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. 3, the relationship between the tread gauge Dcc at 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. 3) that is the outermost point in the tire radial direction of the belt layer 14 and the intersection of the tire equatorial plane CL and the tread profile 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. 3, 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.

  FIG. 5 is an explanatory view showing a main part of the retread tire shown in FIG. The same figure, the expanded sectional view of the circumferential direction main grooves 21 and 22 is shown.

  In FIG. 5, the new lower rubber 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, it is in the range of 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]
6 and 7 are explanatory views showing a modified example of the retreaded tire shown in FIG. These drawings show enlarged cross-sectional views of the tread shoulder region.

  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. In FIG. 4, the tire ground contact edge T and the tread edge coincide with each other, and the tire ground contact edge T is a measurement point of the tread width TW.

  However, the present invention is not limited thereto, and the retread tire 10 may include a shoulder portion having a chamfered shape (see FIG. 6) or a round shape (see FIG. 7) in a sectional view in the tire meridian direction.

  In these configurations, the measurement point of the tread width TW is defined by 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 sidewall portion in a sectional view in the tire meridian direction.

  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.

  For example, in the configuration of FIG. 6, the tread 20 has a square shoulder portion having a chamfered portion 201 in a region including the measurement point T ′ of the tread width. Further, the chamfered portion 201 is in a range from the measurement point T ′ of the tread width TW to a distance of 5 [mm]. Further, the profile in the region from the measurement point T ′ to the point U of the tread width TW of the tread 20 is closer to the tire lumen than the virtual line L3. Accordingly, the rubber volume of the tread 20 in the shoulder region is reduced, and heat generation of the tread rubber in the tread portion shoulder region is suppressed.

  In the configuration of FIG. 6, a single chamfered portion 201 is disposed in a region including the tread width measurement point T ′ and chamfers the edge of the square shoulder portion. However, the present invention is not limited to this, and a plurality of chamfered portions may be disposed adjacent to a region including the tread width measurement point T ′ (not shown).

[effect]
As described above, the retread tire 10 includes the tread 20 and the base tire 30 (see FIG. 1). Further, the base tire 30 includes a carcass layer 13 and a pair of cross belts 141 and 142 disposed on the outer side in the tire radial direction of the carcass layer 13. In addition, when the tire is mounted on the specified rim to apply the specified internal pressure and the load is not loaded, the tread width TW and the total tire width SW are 0.65 ≦ TW / SW ≦ 0.90. 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 foot of the perpendicular line L1 drawn to the tread profile from the point E of the cross belts 141, 142 on the outer side in the tire radial direction is the point R1, and the straight line L2 passing through the point E and perpendicular to the perpendicular line L1 and the profile of the buttress part. The point A1 is the distance A1 from the point E to the point R1 and the distance B1 from the point E to the point S1 has a relationship of 0.90 ≦ B1 / A1 ≦ 1.50 ( (See FIG. 4).

  In this configuration, the ratio TW / SW and the ratio SDH / SH are optimized, so that the profile from the tire equatorial plane CL to the shoulder becomes flat. Then, the amount of deformation of the tread portion at the time of tire rolling is reduced, the separation of the peripheral rubber at the edge portions of the cross belts 141 and 142 is suppressed, and the heat generation of the tread rubber in the tread portion shoulder region is suppressed. Thereby, there exists an advantage which the durable performance of a tire improves.

  In addition, by optimizing the ratio B1 / A1, there is an advantage that the volume of the tread rubber around the edge portion of the cross belt 142 is optimized. That is, by satisfying 0.90 ≦ B1 / A1, a rubber volume in the tread portion shoulder region is appropriately secured, and a failure in the tire manufacturing process is suppressed. Further, when B1 / A1 ≦ 1.50, heat generation of the tread rubber due to an excessive rubber volume in the tread shoulder region is suppressed.

  In this retreaded tire 10, a measurement point of the tread width TW (in FIG. 4, the tire ground contact end) in a cross-sectional view in the tire meridian direction when the tire is mounted on a specified rim to apply a specified internal pressure and is in a no-load state. T) and a profile in the region from the measurement point of the tread width TW to the point U when the virtual line L3 connecting the outer end in the tire width direction of the tread 20 and the point U at the inner end in the tire radial direction is drawn. It is on the tire lumen side from L3 (see FIG. 4). Thereby, there is an advantage that the volume of the tread rubber is reduced and heat generation of the tread rubber in the tread shoulder region is effectively suppressed.

  Further, in this retread tire 10, the tread 20 has a square shoulder portion having a chamfered portion 201 in a region including a measurement point of the tread width TW (see FIG. 6). Thereby, the rubber volume of the tread 20 in the shoulder region is reduced, and there is an advantage that heat generation of the tread rubber in the tread portion shoulder region is suppressed.

  Moreover, in this retread tire 10, the tread 20 has a round-shaped shoulder part (refer FIG. 7). Thereby, compared with the structure which has a square-shaped shoulder part, the rubber volume of the tread 20 in a shoulder area | region is reduced, and there exists an advantage by which the heat_generation | fever of the tread rubber in a tread part shoulder area | region is suppressed.

  Further, in this retreaded tire 10, the inner peripheral surface of the tread 20, the perpendicular L1 and the straight line L2 in a cross-sectional view in the tire meridian direction when the tire is mounted on a prescribed rim to apply a prescribed internal pressure and is in a no-load state. The distance A2 from the point R1 to the point R2 and the distance B2 from the point S1 to the point S2 have a relationship of 0.30 ≦ B2 / A2 ≦ 0.60, where R2 and S2 are intersection points (See FIG. 4). Thereby, the volume (new rubber gauge) of the peripheral rubber at the edge portion of the cross belt 142 is optimized. That is, by satisfying 0.30 ≦ B2 / A2, a new rubber gauge (distance B2) of the buttress portion is ensured, and failure in the tire manufacturing process is suppressed. In addition, since B2 / A2 ≦ 0.60, there is an advantage that a situation where the new rubber gauge of the buttress portion becomes excessive is prevented and heat generation of the tread rubber in the tread portion shoulder region is suppressed.

  Moreover, in this retreaded tire 10, distance B2 exists in the range of 5.0 [mm] <= B2 (refer FIG. 4). Thereby, the new rubber gauge (distance B2) of the buttress part is secured, and the situation where the new rubber gauge of the buttress part becomes excessive is prevented, and there is an advantage that heat generation of the tread rubber in the tread shoulder region 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. Distributed. Thereby, distortion of the tread during tire rolling is reduced, and separation of peripheral rubber at the edge portion of the cross belt is suppressed. Further, since Ga1 ≦ 5.0 [mm], it is possible to prevent the new rubber groove gauge Ga1 of the circumferential main groove 21 from being excessive, and to suppress the heat generation of the tread rubber in the tread region. is there.

  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, distortion of the peripheral rubber at the end portion of the belt layer 14 is reduced, and separation of the peripheral rubber at the edge portion of the cross belt is suppressed. 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. Distributed. Thereby, distortion of the tread during tire rolling is reduced, and separation of peripheral rubber at the edge portion of the cross belt is suppressed. In addition, since Ga2 ≦ 4.0 [mm], the new rubber groove gauge Ga2 of the circumferential main groove 22 is prevented from being excessively large, and the heat generation of the tread rubber in the tread region is suppressed. is there.

  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 reduced, the distortion of the peripheral rubber at the end of the cross belt is increased, and the separation of the peripheral rubber tends to occur. Therefore, there is an advantage that the effect of suppressing the separation of the peripheral rubber at the edge portion of the cross belt can be remarkably obtained by applying the configuration including the carcass layer 13 made of such an organic fiber material.

  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, in the configuration in which the belt cover is made of an organic fiber material, the strength of the belt cover is lowered, the distortion of the peripheral rubber at the end of the cross belt is increased, and the separation of the peripheral rubber tends to occur. Therefore, by adopting a configuration including the belt cover 143 made of such an organic fiber material, there is an advantage that the effect of suppressing the separation of the peripheral rubber at the edge portion of the cross belt can be remarkably obtained.

  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. Thereby, distortion of the tread at the time of tire rolling is reduced, and there is an advantage that separation of peripheral rubber at the edge portion of the cross belt is suppressed. In addition, 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 separation of the peripheral rubber is suppressed. There are advantages.

  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 disposed horizontally with respect to the tire contact surface, the tension acting on the belt ply at the time of tire contact is made uniform. Thereby, distortion of the tread during tire rolling is reduced, and separation of peripheral rubber at the edge portion of the cross belt is suppressed. 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 separation of the surrounding rubber is suppressed.

  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, the belt width Wb1 is ensured by 0.65 ≦ Wb1 / Wa. Thereby, the distortion | strain of the surrounding rubber in the edge part of the tire width direction outer side of the belt layer 14 is reduced, and the separation of surrounding rubber is suppressed. Further, when Wb1 / Wa ≦ 0.90, the distance between the end portion of the belt ply and the sidewall portion is secured. Thereby, distortion of the tread during tire rolling is reduced, and separation of peripheral rubber at the edge portion of the cross belt 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 the load is loaded, but the diameter growth of the tread center area becomes obvious and the contact area of the tread shoulder area tends to decrease when no load is loaded. It is in. Then, the repeated strain at the end of the belt layer increases, and the separation of the peripheral rubber tends to occur. Therefore, there is an advantage that the effect of suppressing the separation of the peripheral rubber at the edge portion of the cross belt can be remarkably obtained by using such a low flat tire for a small truck.

  FIG. 8 is a chart showing the results of the performance test of the retreaded tire according to the embodiment of the present invention.

  In this performance test, the belt edge separation resistance was evaluated for a plurality of types of test tires. A test tire having a tire size of 205 / 70R16 111/109 LT is assembled to a rim having a rim size of 16 × 6.0, and an air pressure of 600 [kPa] and a load of 9.0 [kN] are applied to the test tire. . Then, an endurance test is performed according to the test conditions defined in R54 of the ECE (Economic Commission for Europe). Further, after completion of the test conditions defined in ECE R54, the endurance test is continued by increasing the load by 20 [%] every 10 hours. Then, the travel distance from the end of the belt layer until the breakage occurs is measured, and index evaluation is performed using the conventional example as a reference (100). This evaluation is preferable as the numerical value increases.

  The test tires of Examples 1 to 13 have the structure described in FIGS. The tire total width SW is SW = 204 [mm], and the tire cross-section height SH is SH = 143.7 [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]. In Example 1, the distance A1 is A1 = 14.5 [mm], and the distance A2 is A2 = 21.0 [mm].

  The test tire of the conventional example has a ratio B1 / A1 of B1 / A1 = 0.85 in the configurations of FIGS. Further, the profile of the buttress portion in FIG. 4 has a flat shape along the virtual line L3.

  As shown in the test results, it can be seen that in the test tires of Examples 1 to 13, the belt edge separation resistance of the tire is improved.

  10: Rehabilitated tire, 20: Tread, 201: Chamfer, 30: Stand tire, 301: Residual tread, 11: Bead core, 12: Bead filler, 13: Carcass layer, 14: Belt layer, 141, 142: Cross belt 143, 144: belt cover, 15: tread rubber, 16: side wall rubber, 17: rim cushion rubber, 21, 22: circumferential main groove, 31, 32: land portion

Claims (16)

A tread and a base tire, and
The base tire is a retread tire having a carcass layer and a pair of intersecting belts arranged on the outer side in the tire radial direction of the carcass layer,
In a cross-sectional view in the tire meridian direction when a tire is mounted on a specified rim and applied with a specified internal pressure and in a no-load state,
The tread width TW and the tire total width SW have a relationship of 0.65 ≦ TW / SW ≦ 0.90,
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,
The leg of the perpendicular line L1 drawn to the tread profile from the point E of the cross belt at the outer side in the tire radial direction is defined as a point R1, and the intersection point between the straight line L2 passing through the point E and perpendicular to the perpendicular line L1 and the profile of the buttress part. As point S1,
A retread tire characterized in that the distance A1 from the point E to the point R1 and the distance B1 from the point E to the point S1 have a relationship of 0.90 ≦ B1 / A1 ≦ 1.50. When a tire is mounted on a specified rim to provide a specified internal pressure and in a no-load state, the tread width TW measurement point, the tread width in the tire width direction outside, and the tire radial direction inside in the tire meridian direction When drawing a virtual line L3 connecting the point U at the end,
The retread tire according to claim 1, wherein the profile in the region from the measurement point to the point U of the tread width TW is closer to the tire lumen than the virtual line L3.   The retread tire according to claim 1 or 2, wherein the tread has a square shoulder portion having a chamfered portion in a region including a measurement point of the tread width.   The retread tire according to claim 1 or 2 in which said tread has a round-shaped shoulder part. A cross-sectional view in the tire meridian direction when a tire is mounted on a specified rim to apply a specified internal pressure and is in a no-load state, the intersections of the inner peripheral surface of the tread with the perpendicular L1 and the straight line L2 are R2, S2, and When
The distance A2 from the point R1 to the point R2 and the distance B2 from the point S1 to the point S2 have a relationship of 0.30 ≦ B2 / A2 ≦ 0.60, according to any one of claims 1 to 4. Rehabilitation tire.   The retreaded tire according to claim 5, wherein the distance B2 is in a range of 5.0 [mm]? B2.   A new rubber sub-groove gauge Ga1 of the circumferential main groove that has a plurality of circumferential main grooves and is closest to the tire equatorial plane is in the range of 1.0 [mm] ≦ Ga1 ≦ 5.0 [mm]. The retreaded tire according to any one of claims 1 to 6.   The new rubber sub-groove gauge Ga2 of the circumferential main groove at the outermost side in the tire width direction is in a range of Ga2 <Ga1 and 1.0 [mm] ≦ Ga2 ≦ 4.0 [mm]. Rehabilitation tire.   The retread tire according to any one of claims 1 to 8, further comprising a carcass layer, wherein the carcass layer is configured by arranging a plurality of carcass cords made of an organic fiber material.   10. A belt cover according to claim 1, 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 the tire circumferential direction. Rehabilitation tire according to any one of the above. 2. A belt cover is provided, and the single or plural belt covers are arranged so as to cover at least a position intersecting the tire equatorial plane and an end portion of the pair of intersecting belts on the outer side in the tire width direction. The retreaded tire as described in any one of -10.   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. Rehabilitated tire. The rehabilitated tire according to any one of claims 1 to 13 , further comprising a belt cover , wherein an end number of the belt cover is in a range of 40 [lines / 50mm] to 60 [lines / 50mm]. The belt cover is provided, and the thickness of the thread constituting the belt cover is in the range of 1100 [dtex / 2] to 1500 [dtex / 2]. Rehabilitated tire.   The retreaded tire according to any one of claims 1 to 15, which has a flatness ratio of 70% or less.

Images