Patent Description:
Conventionally, a pneumatic tire has been known which includes a puncture prevention function whereby a hole in the tire formed during puncture is automatically plugged by a sealant layer provided to the inner surface of the tire. For example, Patent Document <NUM> discloses a pneumatic tire in which a sealant layer is formed on the tire inner surface, and a sound absorbing layer is provided to the inner side of this sealant layer. <CIT> describes a self-sealing tire including a sealant layer located radially inside an innerliner. The sealant layer is formed by applying a sealant to the inner periphery of a tire from which mold release agents have been removed. Such a pneumatic tire has sufficient sealing performance. <CIT> describes a pneumatic tire and a method for producing a pneumatic tire.

In a tire having a sound absorbing layer, the unwanted noise generated from the tire during travel such as road noise decreases due to being absorbed by the sound absorbing layer. On the other hand, the sealant layer is normally arranged so as to cover the entirety of the tire inner surface of an area corresponding to the tread of the tire; therefore, the tire inner surface covered by the sealant layer stores heat, and there is concern over the tire deteriorating from the influence of this heat, and the durability declining. Therefore, in the point of achieving both noise suppression and suppression of a tire durability decline caused by the sealant layer, there has been room for improvement in conventional tires.

The present invention has been made taking account of the above situation, and has an object of providing a pneumatic tire and a method for producing the same which can achieve both noise suppression and suppression of a tire durability decline caused by a sealant layer. Preferred examples are defined in the dependent claims.

A pneumatic tire according to the present invention includes: a pair of beads; a pair of sidewalls extending from each of the pair of beads to an outer side in a tire-radial direction; a tread disposed between the pair of sidewalls and having a tread surface; a carcass ply bridged between the pair of beads; an inner liner disposed at a tire inner cavity side of the carcass ply; a sealant layer disposed on an inner surface at the tire inner cavity side of the inner liner; and a sound absorbing layer disposed at a tire inner cavity side of the sealant layer, in which a plurality of grooves extending in a tire-circumferential direction is disposed in the tread surface of the tread, the sealant layer has a plurality of circling parts provided in a belt shape in an annular portion of the inner surface of the inner liner corresponding to each of the plurality of grooves, and the sound absorbing layer is disposed in a shape spanning in the tire-width direction the plurality of circling parts.

A method for manufacturing the pneumatic tire according to the present invention includes: a sealant layer formation step of discharging a sealant material to coat a tire inner surface from a nozzle disposed on a tire inner cavity side, while rotating a tire in which a plurality of grooves extending in a tire-circumferential direction are formed in a tread surface of a tread around an axis thereof; and a sound absorbing layer arrangement step of arranging a sound absorbing layer on the sealant layer, in which the sealant layer formation step grasps groove position information indicating a position of each of the plurality of grooves, and forms a plurality of belt-shaped circling parts from a sealant material in an annular portion corresponding to each of the plurality of grooves, by coating the sealant material in the annular portion corresponding to each of the plurality of grooves on a tire inner surface, by moving a nozzle relatively in the tire-width direction in relation to the tire, based on the groove position information thus grasped, and the sound absorbing layer arrangement step arranges the sound absorbing layer in a state spanning in the tire-width direction the plurality of circling parts thus formed.

The present invention has been made taking account of the above situation, and has an object of providing a pneumatic tire and a method for producing the same which can achieve both noise suppression and suppression of a tire durability decline caused by a sealant layer.

Hereinafter, an embodiment will be explained while referencing the drawings. <FIG> is a view showing a tire-width direction cross section of a tire <NUM>, which is a pneumatic tire according to the present embodiment. The tire <NUM> is a tire for a passenger vehicle, for example. The specific structure of the tire <NUM> is left/right symmetrical in a cross section in the tire-width direction. In the drawings, reference symbol S1 is a tire equatorial plane. The tire equatorial plane S1 is a plane intersecting a tire rotational axis (tire meridian axis), and is positioned at the center in the tire-width direction.

It should be noted that the cross-sectional view of <FIG> is a tire-width direction cross-sectional view (tire meridian axis cross-sectional view) of an unloaded state in which the tire <NUM> is mounted to a standard rim and filled with standard internal pressure. It should be noted that standard rim indicates a rim serving as a standard decided by JATMA corresponding to the tire size. In addition, standard internal pressure is <NUM> kPa in the case of the tire being for a passenger vehicle, for example.

Herein, tire-width direction is a direction parallel to the tire rotational axis, and is the left/right direction in the paper plane in the cross-sectional view of <FIG>. In <FIG>, it is illustrated as the tire-width direction X. Then, the tire-width direction inner side is a direction near the tire equatorial plane S1, and is the central side in the paper plane of <FIG>. Tire-width direction outer side is a direction distanced from the tire equatorial plane S1, and is the left side and right side in the paper plane of <FIG>. In addition, tire-radial direction is a direction perpendicular to the tire rotational axis, and is the vertical direction in <FIG>. In <FIG>, it is illustrated as the tire-radial direction Y. Then, a tire-radial direction outer side is a direction distanced from the tire rotational axis, and is a lower side in the paper plane of <FIG>. Tire-radial direction inner side is a direction approaching the tire rotational axis, and is an upper side in the paper plane of <FIG>.

As shown in <FIG>, the tire <NUM> includes: a pair of beads <NUM> provided at both sides in the tire-width direction; a pair of sidewalls <NUM> extending from each of the pair of beads <NUM> to the outer side in the tire-radial direction; tread <NUM> arranged between the pair of sidewalls <NUM>; a carcass ply <NUM> arranged between the pair of beads <NUM>; and an inner liner <NUM> arranged on the tire inner cavity side of the carcass ply <NUM>.

The bead <NUM> includes a bead core <NUM>, bead filler <NUM> extending in the tire-radial direction outer side of the bead core <NUM>, a chafer <NUM>, and rim strip rubber <NUM>.

The bead core <NUM> is an annular member formed by winding a bead wire made of metal covered with rubber around several times, and is a member playing the role of fixing the tire <NUM> filled with air to the rim. The bead filler <NUM> is a rubber member which takes on a tapered shape as extending to the outer side in the tire radial direction. The bead filler <NUM> is a member provided to raise the rigidity of a circumferential portion of the bead <NUM>, and ensure high maneuverability and stability. The bead filler <NUM>, for example, is configured from rubber having higher hardness than the surrounding rubber members.

The chafer <NUM> is provided to the inner side in the tire-radial direction of the carcass ply <NUM> provided around the bead core <NUM>. The rim strip rubber <NUM> is arranged on the outer side in the tire-width direction of the chafer <NUM> and carcass ply <NUM>. The rim strip rubber <NUM> is a member which contacts the rim to which the tire <NUM> is mounted.

The sidewall <NUM> includes sidewall rubber <NUM> arranged on the outer side in the tire-width direction of the carcass ply <NUM>. The sidewall rubber <NUM> configures an outer wall surface of the tire <NUM>. The sidewall rubber <NUM> is a portion which bends the most upon the tire <NUM> exhibiting a cushioning action, and usually flexible rubber having fatigue resistance is adopted therein.

The tread <NUM> includes an endless belt <NUM> and cap ply <NUM>, and tread rubber <NUM>.

The belt <NUM> is arranged at an outer side in the tire-radial direction of the carcass ply <NUM>. The cap ply <NUM> is arranged at an outer side in the tire-radial direction of the belt <NUM>. The belt <NUM> is a member reinforcing the tread <NUM>. The belt <NUM> in the present embodiment is a two-layer structure including a belt <NUM> on the inner side and a belt <NUM> on the outer side. The belt <NUM> on the inner side and the belt <NUM> on the outer side both have a structure in which a plurality of cords such as steel cords is covered with rubber. It should be noted that the belt <NUM> is not limited to a two-layer structure, and may have a structure of one layer or three or more layers.

The cap ply <NUM> is a member reinforcing the tread <NUM> together with the belt <NUM>. The cap ply <NUM>, for example, has a structure in which a plurality of organic fiber cords having an insulation property such as polyimide fibers is covered with rubber. By providing the cap ply <NUM>, it is possible to achieve an improvement in durability and a reduction in road noise during travel.

The tread rubber <NUM> is arranged on the outer side in the tire-radial direction of the cap ply <NUM>. The tread rubber <NUM> is a member constituting the tire tread <NUM> which contacts the road surface during travel. A tread pattern <NUM> configured by a plurality of grooves, for example, is provided in the tread surface <NUM> of the tread rubber <NUM>. The tread pattern <NUM> has a plurality of main grooves <NUM> aligned in the tire-width direction. Each of the plurality of main grooves <NUM> extends along the tire circumferential direction. The main groove <NUM> is an example of a groove.

In the present embodiment, four of the main grooves <NUM> are formed in the tread surface <NUM>. The four main grooves <NUM> are arranged in left/right symmetry with the tire-width direction center of the tread surface <NUM> as the center of symmetry. It should be noted that the number and arrangement of the main grooves <NUM> are not limited thereto. For example, the plurality of main grooves <NUM> may be arranged non-symmetrically rather than being at symmetrical positions with the center in the tire-width direction as the center of symmetry.

In the tread surface <NUM> of the tread <NUM>, a plurality of center land parts <NUM> are arranged between the plurality of main grooves <NUM>. Each of the plurality of center land parts <NUM> extends in the tire-circumferential direction. In addition, the tread surface <NUM> of the tread <NUM> may respectively have a lateral land part <NUM> having a tire thickness on the same order as the center land part <NUM>, in a portion more to the outer side in the tire-width direction than the two main grooves <NUM> arranged the most outwards in the tire-width direction.

The carcass ply <NUM> configures a ply serving as the backbone of the tire <NUM>. The carcass ply <NUM> is embedded within the tire <NUM>, in a form passing through the pair of sidewalls <NUM> and the tread <NUM> between the pair of beads <NUM>. The carcass ply <NUM> includes a plurality of carcass cords serving as the backbone of the tire <NUM>. The plurality of carcass cords extends in the tire-width direction, for example, and are arranged side by side in the tire-circumferential direction. This carcass cord is configured from an insulative organic fiber cord such as polyester or polyamide, or the like. The plurality of carcass cords is coated by rubber, whereby the carcass ply <NUM> is configured.

The carcass ply <NUM> includes a ply main body part <NUM> which extends from one bead core <NUM> to the other bead core <NUM>, and extends between the tread <NUM> and bead <NUM>; a pair of elbow-shaped bends <NUM> which fold back from the ply main body part <NUM> at the bead core <NUM>; and a pair of folding parts <NUM> which extend from each of the elbow-shaped bends <NUM> to an outer side in the tire-radial direction. The ply main body part <NUM>, the elbow-shaped bend <NUM> and folding part <NUM> are continuous.

The ply main body part <NUM> is arranged at the inner side in the tire-width direction of the bead core <NUM> and bead filler <NUM> on the inner side in the tire-radial direction The folding part <NUM> is arranged at the outer side in the tire-width direction of the bead core <NUM> and bead filler <NUM> at the inner side in the tire-radial direction. In a portion other than the bead core <NUM> and bead filler <NUM>, the folding part <NUM> is overlapped with the ply main body part <NUM>. The elbow-shaped bend <NUM> configures a portion most to the inner side in the tire-radial direction of the carcass ply <NUM>.

The carcass ply <NUM> of the present embodiment is a one-layer structure; however, the carcass ply <NUM> is not limited to a one-layer structure, and may have a two-layer or three or more layer-structure.

The aforementioned chafer <NUM> of the bead <NUM> is provided so as to surround the end on the inner side in the tire-radial direction of the carcass ply <NUM> including the elbow-shaped bend <NUM>. In addition, the rim strip rubber <NUM> is arranged at the outer side in the tire-width direction of the chafer <NUM> and the folding part <NUM> of the carcass ply <NUM>. The end on the outer side in the tire-radial direction of the rim strip rubber <NUM> is covered by the aforementioned sidewall rubber <NUM>.

The inner liner <NUM> covers the tire inner surface between the pair of beads. The inner liner <NUM> covers the inner surface of the ply main body part <NUM> of the carcass ply <NUM> and the inner surface of the chafer <NUM> of the pair of beads <NUM>. The inner liner <NUM> is configured by air permeation resistant rubber, whereby the air inside the tire inner cavity is prevented from leaking to outside.

As shown in <FIG>, the tire <NUM> according to the present embodiment further includes the sealant layer <NUM>. The sealant layer <NUM> and sound absorbing layer <NUM> are further included.

As shown in <FIG>, the sealant layer <NUM> is provided to the inner surface <NUM> of the inner liner <NUM>, which is the tire inner surface. In the present embodiment, the sealant layer <NUM> includes circling parts <NUM> provided in a belt shape to an annular portion corresponding to the plurality of main grooves <NUM> provided to the tread surface <NUM> of the tread <NUM>. The sealant layer <NUM> is pasted to the inner surface <NUM> of the inner liner <NUM> by way of the stickiness of itself.

<FIG> is a development view showing the inner surface of the tire <NUM>, and schematically shows the sealant layer <NUM> provided to the inner surface of the tire <NUM>. <FIG> shows the tire-width direction by the arrow X, and shows the tire-circumferential direction by the arrow Z.

As shown in <FIG>, the sealant layer <NUM> is formed from one belt-like sealant material <NUM> pasted while circling along the tire-circumferential direction to the inner surface <NUM> of the inner liner <NUM>. The sealant layer <NUM> has a plurality of annular circling parts <NUM> and a plurality of transition parts <NUM> formed by the sealant material <NUM>.

In <FIG>, the reference symbol 61A indicates the pasting starting end of the sealant material <NUM>, and reference symbol 61B indicates the pasting finishing end of the sealant material <NUM>. As shown in <FIG>, the sealant material <NUM> is continuously pasted from one end side in the tire-width direction to the other end side (left side to right side in <FIG>), while circling to configure as shown by the arrow in the middle drawing, from the pasting starting end 61A until the pasting finishing end 61B.

The circling part <NUM> is formed by the sealant material <NUM> being pasted on the inner surface <NUM> of the inner liner <NUM> in parallel to the tire-circumferential direction. By the sealant material <NUM> circling around once or a plurality of times and pasting to the inner surface <NUM> of the inner liner <NUM>, one belt-shaped circling part <NUM> is formed.

The plurality of circling parts <NUM> are arranged in parallel at intervals in the tire-width direction. Each of the plurality of circling parts <NUM> is provided in a belt shape to an annular portion of the inner surface <NUM> of the inner liner <NUM> corresponding to each of the plurality of main grooves <NUM>. In other words, each of the plurality of circling parts <NUM> is respectively arranged on the inner side in the tire-radial direction of the plurality of the main grooves <NUM>. In the present embodiment, since there are four of the main grooves <NUM>, four of the circling parts <NUM> are formed. The width of each of the plurality of circling parts <NUM> has a dimension of at least the width of each corresponding main groove <NUM>. Each of the plurality of circling parts <NUM> preferably covers the corresponding respective main groove <NUM> in the tire-width direction.

The transition part <NUM> is a portion at which the sealant material <NUM> transitions to one side in the tire-width direction (right side in <FIG>), after the sealant material <NUM> circles approximately once or several times and is pasted to the inner surface <NUM> of the inner liner <NUM>, whereby one circling part <NUM> is formed. In other words, the transition part <NUM> is a portion provided to part of the circling part <NUM>, and connecting circling parts <NUM> adjacent in the tire-width direction form an angle relative to the tire-circumferential direction. In other words, the transition part <NUM> is provided between a pair of circling parts <NUM> adjacent in the tire-width direction. The next circling part <NUM> is pasted at an interval at one side in the tire-width direction of the pasted circling part <NUM> via the transition part <NUM>. The interval portion of an adjacent pair of circling parts <NUM> corresponds to the center land part <NUM>. The next circling part <NUM> adjacent on one side in the tire-width direction via the transition part <NUM> is repeatedly formed, whereby the sealant layer <NUM> is provided.

Each of the plurality of transition parts <NUM> extends linearly in a state sloping with a predetermined angle relative to the tire-circumferential direction. In the present embodiment, since there are four main grooves <NUM>, the transition parts <NUM> are provided one between circling parts <NUM>, for a total of three. As shown in <FIG>, in the present embodiment, three of the transition parts <NUM> are arranged substantially linearly as a whole, while being shifted in the tire-circumferential direction. It should be noted that the plurality of transition parts <NUM> are arranged in parallel in the tire-width direction, and the mode of arrangement is not limited.

In this way, upon pasting the sealant material <NUM> to the tire inner surface, the pasting method of sequentially pasting in the tire-width direction the circling parts <NUM> parallel in the tire-circumferential direction while passing through the transition parts <NUM> may be referred to as step pasting below.

As the sealant material <NUM>, for example, it is possible to use a sealing member having stickiness made by blending a plasticizer such as polyisobutylene and polybutene, a tackifier such as a thermoplastic olefin/diolefin copolymer, and a filler such as carbon black and silica, into unvulcanized or semi-vulcanized butyl rubber, for example. It should be noted that, not limiting thereto, the sealant material <NUM> may be another known sealing member that is being used conventionally.

To step paste the sealant material <NUM>, it is possible to perform by discharging and coating the sealant material <NUM> onto the inner surface <NUM> of the inner liner <NUM>, which is the inner surface of the tire <NUM>, from the nozzle <NUM>, while rotating the tire <NUM> around its axis, and moving the nozzle <NUM> in the tire-width direction, as shown in <FIG>. In <FIG>, the width-direction cross section of the tire <NUM> is shown, and the tire-width direction X, tire-radial direction Y and tire-circumferential direction Z are each shown. In <FIG>, the reference symbol G is the axis of rotation of the tire <NUM>.

By configuring as shown in <FIG>, upon step pasting the sealant material <NUM> to the inner surface of the tire <NUM>, it is possible to use a sealant material coater <NUM> shown in <FIG>.

<FIG> shows an outline configuration of the sealant material coater <NUM>, and this sealant material coater <NUM> includes a tire rotation mechanism <NUM>, nozzle slide mechanism <NUM>, sealant material discharge mechanism <NUM> and controller <NUM>.

The tire rotation mechanism <NUM> is a mechanism causing the tire <NUM> after vulcanization in a state in which the sealant layer <NUM> has not been formed to rotate around its axis as shown in <FIG>. The nozzle slide mechanism <NUM> is a mechanism which causes the nozzle <NUM> to move in the tire-width direction relative to the tire <NUM> set in the tire rotation mechanism <NUM>.

The sealant material discharge mechanism <NUM> includes the above-mentioned nozzle <NUM>, and an extruder (not shown) to which the nozzle <NUM> is mounted at the leading end. The nozzle <NUM> is inserted to the inner side of the tire <NUM> set in the tire rotation mechanism <NUM>. The sealant material discharge mechanism <NUM> discharges to coat the sealant material <NUM> extruded from the above-mentioned extruder to the inner surface of the tire <NUM> from the leading end of the nozzle <NUM>.

The controller <NUM> inputs groove position information. The controller <NUM> controls operations of each of the tire rotation mechanism <NUM>, nozzle slide mechanism <NUM> and sealant material discharge mechanism <NUM>, based on the inputted groove position information.

In the present embodiment, the above-mentioned groove position information includes: coordinates indicating each of the position and width in the tire-width direction of the plurality of main grooves <NUM> formed in the tread <NUM> of tire <NUM>, and width of center land part <NUM> between main grooves <NUM>, and the circumferential-direction length of the inner surface <NUM> of the inner liner <NUM> on which the sealant material <NUM> is coated. Such groove position information can be obtained based on CAD data during tire design, for example. It should be noted that each coordinate related to the tire-width direction of the main groove <NUM> can be obtained by a method such as scanning the tread surface <NUM> of the tread <NUM> of the vulcanized tire <NUM> with a laser beam. It should be noted that the acquisition method of the groove position information is not limited thereto, and may adopt another appropriate method.

The controller <NUM> to which the groove position information is inputted grasps this groove position information and controls operations of the tire rotation mechanism <NUM>, nozzle slide mechanism <NUM> and sealant material discharge mechanism <NUM>.

The sealant material coater <NUM> operates in the following way, the sealant material <NUM> is step pasted to the inner surface of the tire <NUM> and the sealant layer <NUM> is formed, followed by the sound absorbing layer <NUM> being arranged on the sealant layer <NUM>. The formation of the sealant layer <NUM> and arrangement of the sound absorbing layer <NUM> explained below are examples of a method of producing the tire according to the present embodiment. The method for producing the tire according to the present embodiment includes a sealant layer formation step and a sound absorbing layer arrangement step.

By rotating the tire <NUM> in a state stopping movement in the tire-width direction of the nozzle <NUM>, while discharging the sealant material <NUM> continuously from the nozzle <NUM>, and while rotating the tire <NUM> around its axis, an initial circling part <NUM> on one end side in the tire-width direction is coated. Next, the nozzle <NUM> is moved to one side in the tire-width direction, and the nozzle <NUM> is arranged at the formation position of the next circling part <NUM>. During this movement, the transition part <NUM> is coated. Next, movement to the tire-width direction of the nozzle <NUM> is stopped, and the circling part <NUM> is coated. By repeating the above operations, the sealant material <NUM> is step pasted. When a predetermined number (four in present embodiment) of the circling parts <NUM> are formed from the sealant material <NUM>, discharge of the sealant material <NUM> from the nozzle <NUM> is stopped.

The controller <NUM> controls the slide operation to the tire-width direction of the nozzle <NUM> by the nozzle slide mechanism <NUM>, so that the sealant material <NUM> is coated to correspond to a plurality of the main groove <NUM>, based on the coordinates related to the tire-width direction of the plurality of main grooves <NUM>. In addition, the controller <NUM> controls so that the circling part <NUM> extending in the tire-circumferential direction is coated over the entire circumference of the inner surface <NUM>, based on the circumferential-direction length of the inner surface <NUM> of the inner liner <NUM>. One circling part <NUM> is formed by the sealant material <NUM> being coated around once. Alternatively, one circling part <NUM> is formed by the tire <NUM> moving little by little over several times in the tire-width direction, and the sealant material <NUM> being coated over a plurality of rotations.

The sound absorbing layer <NUM> is arranged in a state spanning in the tire-width direction over a plurality of circling parts <NUM> of the aforementioned sealant layer <NUM>. The circling part <NUM> having a predetermined thickness serves as a spacer between the sound absorbing layer <NUM> and the inner surface <NUM> of the inner liner <NUM>, whereby an interval is formed. In other words, the sound absorbing layer <NUM> is arranged in a state floating on the inner surface <NUM> of the inner liner <NUM>. Then, in the area in which the sound absorbing layer <NUM> is arranged, a plurality of cavity parts <NUM> surrounded by the sound absorbing layer <NUM>, inner surface <NUM> of the inner liner <NUM>, and pair of circling parts <NUM> adjacent to the tire-width direction are formed. The plurality of cavity parts <NUM> are formed in an annular shape along the tire-circumferential direction.

The sound absorbing layer <NUM> is formed with a sound absorbing material <NUM> consisting of sponge or the like formed with foaming material. The sound absorbing material <NUM> is an interconnecting foam body including several pores, and having permeability with outside air. As such a material, for example, flexible urethane foam can be exemplified.

In the sound absorbing layer <NUM>, at least one sheet of sound absorbing material <NUM> is pasted to wind in a ring shape on the inner surface <NUM> of a plurality of circling parts <NUM> on the sealant layer <NUM>. As shown in <FIG>, the sound absorbing material <NUM> is arranged so as to span in the tire-width direction a plurality of circling parts <NUM>, and is wound and pasted in a ring shape on the inner surface <NUM> of the plurality of circling parts <NUM>. Each of both ends in the tire-width direction of the sound absorbing layer <NUM> extends more to an outer side in the tire-width direction than each main groove <NUM> arranged most outwards in the tire-width direction Each of both tire-width direction ends of the sound absorbing layer <NUM> extends more to the outer side in the tire-width direction than the circling part <NUM> arranged most outwards in the tire-width direction. It should be noted that the sound absorbing layer <NUM> may be configured by at least two sound absorbing materials <NUM> being arranged in a state linked in a ring shape.

As characteristics of the sound absorbing material <NUM>, from the viewpoint of weight balance of the pneumatic tire, it preferably has density no greater than <NUM>/m<NUM>, and more preferably has density no greater than <NUM>/m<NUM>. In addition, the sound absorbing material <NUM>, from the viewpoint of durability, preferably has a tensile strength of at least <NUM> kPA, and a tear strength of at least <NUM> N/cm (JIS K6400-<NUM>).

According to the tire <NUM> of the aforementioned embodiment, the case of a puncture elicitor such as a nail or rivet passing through the main groove <NUM> and sticking has less resistance upon sticking due to the tire thickness being smaller, than a case of sticking in the center land part <NUM> between main grooves <NUM>, or lateral land part <NUM>, and thus a puncture elicitor tends to puncture to reach the tire inner cavity. Conversely, since the tire thickness is large at the center land part <NUM> and lateral land part <NUM>, the resistance is great upon a puncture elicitor sticking, and thus even if the puncture elicitor sticks in the center land part <NUM> or lateral land part <NUM>, it will hardly puncture.

In the tire <NUM> according to the present embodiment, the circling part <NUM> of the sealant layer <NUM> is formed in a belt shape, on the inner surface <NUM> of the inner liner <NUM> on the tire inner cavity side of the main groove <NUM>, corresponding to the main groove <NUM>, which is a portion that tends to puncture in the above way. For this reason, in the case of a hole reaching the circling part <NUM> occurring due to a puncture elicitor passing through the main groove <NUM>, this hole is automatically plugged by the circling part <NUM>, whereby the puncture is prevented before it happens. Therefore, puncture is prevented with high probability by the sealant layer <NUM>, and the puncture prevention function is maintained. The thickness of the circling part <NUM> preventing puncture is preferably on the order of at least <NUM> and no more than <NUM>, for example.

In the present embodiment, the sealant layer <NUM> is provided in a belt-shape to the inner surface <NUM> of the inner liner <NUM> on the tire inner cavity side of each main groove <NUM> to correspond to the plurality of main grooves <NUM>, and does not cover the entire surface of the tire inner surface of an area corresponding to the tread <NUM>. In other words, in the present embodiment, the puncture prevention function is imparted by the plurality of circling parts <NUM> arranged to correspond to the respective main grooves <NUM>. In this way, in addition to the structure in which the sealant layer <NUM> has a plurality of circling parts <NUM> distributed in the tire-width direction, since the sound absorbing layer <NUM> covering the sealant layer <NUM> is arranged in a state floating from the inner surface <NUM> of the inner liner <NUM>, heat storage of the tire <NUM> is suppressed by the sealant layer <NUM>, a result of which a decline in tire durability caused by this heat storage is suppressed.

In addition, according to the method for producing the tire according to the present embodiment using the aforementioned sealant material coater <NUM>, it is possible to suitably form the tire <NUM> of the present embodiment having the sealant layer <NUM>.

In addition, according to the tire <NUM> of the aforementioned embodiment, unwanted sound such as road noise during travel is absorbed by the sound absorbing layer <NUM> and decreases. The sound absorbing layer <NUM> is arranged by being pasted to the inner surface <NUM> of a plurality of circling parts <NUM> of the sealant layer <NUM>, and thus floats from the inner surface <NUM> of the inner liner <NUM>, and a plurality of cavity parts <NUM> are formed between this inner surface <NUM> and sealant layer <NUM>. When the unwanted noise such as road noise generated at the side of the tread <NUM> passes through the plurality of cavity parts <NUM> and passes through the sound absorbing layer <NUM>, the sound energy decreases upon passing through the cavity part <NUM>, and thus unwanted noise effectively decreases.

According to the present embodiment explained above, the following effects are exerted.

Although a specific embodiment of the present invention has been explained above, the present invention is not limited to the above embodiment, and even if carrying out modifications, improvements and the like in a scope that can achieve the object of the present invention, are included in the scope of the present invention. For example, in the above-mentioned embodiment, the plurality of main grooves <NUM> are arranged left/right symmetrical with the tire-width direction center of the tread surface <NUM> as the center of symmetry; however, the plurality of main grooves <NUM> may be arranged non-symmetrically, rather than being symmetrical positions with the tire-width direction center as the center of symmetry. The circling parts <NUM> of the sealant layer <NUM> are arranged on the inner surface <NUM> of the inner liner <NUM> to correspond to these non-symmetrical main grooves <NUM>. In the case of step pasting the sealant material <NUM> to form the plurality of circling parts <NUM>, the tire <NUM> may be moved in the tire-width direction, or both the tire <NUM> and nozzle <NUM> may both be moved in the tire-width direction, instead of moving the nozzle <NUM> in the tire-width direction. In the above-mentioned embodiment, the plurality of circling parts <NUM> of the sealant layer <NUM> provide the sealant material <NUM> by the aforementioned step pasting; however, the plurality of circling parts <NUM> may be provided by winding the sealant material <NUM> in a spiral shape.

Claim 1:
A pneumatic tire (<NUM>) comprising:
a pair of beads (<NUM>);
a pair of sidewalls (<NUM>) extending from each of the pair of beads (<NUM>) to an outer side in a tire-radial direction;
a tread (<NUM>) disposed between the pair of sidewalls (<NUM>) and having a tread surface (<NUM>);
a carcass ply (<NUM>) bridged between the pair of beads (<NUM>);
an inner liner (<NUM>) disposed at a tire inner cavity side of the carcass ply (<NUM>);
a sealant layer (<NUM>) disposed on an inner surface (<NUM>) at the tire inner cavity side of the inner liner (<NUM>); and
a sound absorbing layer (<NUM>) disposed at a tire inner cavity side of the sealant layer (<NUM>),
characterized in that
a plurality of grooves (<NUM>) extending in a tire-circumferential direction is disposed in the tread surface (<NUM>) of the tread (<NUM>),
wherein the sealant layer (<NUM>) has a plurality of circling parts (<NUM>) provided in a belt shape in an annular portion of the inner surface (<NUM>) of the inner liner (<NUM>) corresponding to each of the plurality of grooves (<NUM>), and
wherein the sound absorbing layer (<NUM>) is disposed in a shape spanning in the tire-width direction the plurality of circling parts (<NUM>).