JP2019209530A - Method for manufacturing pneumatic tire - Google Patents

Abstract

To provide a method for manufacturing a pneumatic tire capable of imparting a predetermined diametrical difference to a belt with a simple method.SOLUTION: A method for manufacturing a pneumatic tire includes: a step of preparing a cylindrical resin member 100; a step of deforming the resin member 100 to a predetermined shape; and a step of winding the cord coated with a coating material around the axis of the resin member 100 on the resin member 100 deformed to the predetermined shape to form a belt having a cord.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a pneumatic tire.

  Conventionally, in a pneumatic tire, a belt is usually disposed outside the carcass in the tire radial direction in order to improve tire performance (for example, Patent Document 1).

  The belt shall have a state in which a resin-coated cord or a rubber-coated cord coated with a coating material such as resin or rubber is spirally wound in the tire circumferential direction (hereinafter referred to as a spiral belt). Has also been proposed.

Japanese Patent Laid-Open No. 10-035220

  Here, the belt may be required to be configured to have a predetermined diameter difference in the tire width direction depending on the required tire performance.

  The belt may be given a predetermined shape by expansion during tire vulcanization, but in the case of a so-called spiral belt, the rigidity in the tire circumferential direction is high. It is difficult to give a difference.

  Then, this invention aims at providing the manufacturing method of a pneumatic tire which can give a predetermined diameter difference to a belt with a simple method.

The gist configuration of the present invention is as follows.
The method for producing a pneumatic tire of the present invention includes:
A step of preparing a cylindrical resin member;
Transforming the resin member into a predetermined shape;
Forming a belt having the cord by winding a cord coated with a coating material around the axis of the resin member on the resin member deformed into the predetermined shape. And
According to the method for manufacturing a pneumatic tire of the present invention, a predetermined diameter difference can be imparted to the belt by a simple method.

In the manufacturing method of the pneumatic tire of the present invention,
The step of deforming the resin member into the predetermined shape is preferably performed by applying heat and / or force to the resin member.
According to this method, the resin member can be deformed into a predetermined shape by a simpler method.

In the manufacturing method of the pneumatic tire of the present invention,
The predetermined shape is preferably a shape in which the diameter of the cylinder is different in the axial direction of the cylindrical resin member.
According to this method, a belt having a shape having a diameter difference in the tire width direction can be easily formed.

In the manufacturing method of the pneumatic tire of the present invention,
The predetermined shape is preferably a shape in which the diameter of the cylinder gradually decreases from the axial center to the end of the cylindrical resin member.
According to this method, a belt having a shape whose diameter gradually decreases from the center in the tire width direction toward the end can be easily formed.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the pneumatic tire which can give a predetermined | prescribed diameter difference to a belt with a simple method can be provided.

It is a side view which shows a cylindrical resin member. It is a side view which shows the cut | disconnected resin member. It is a perspective view which shows an example of a jig. It is a perspective view which expands and shows a part of jig concerning FIG. It is a perspective view which shows the state in which the heated resin member was set to the jig. It is a perspective view which shows typically a mode that the resin member of the state set to the jig is pressed against the inner surface of a jig. It is a fragmentary perspective view which shows a mode that the shape of the resin member followed the shape of the jig. It is a perspective view which shows the other example of a jig. It is a perspective view which expands and shows a part of jig concerning FIG. It is a perspective view which shows the state in which the heated resin member was set to the jig. It is a perspective view which shows typically a mode that the resin member of the state set to the jig thermally contracts with an arrow. It is a fragmentary perspective view which shows a mode that the shape of the resin member followed the shape of the jig. It is a tire width direction schematic sectional drawing which shows an example of the manufactured pneumatic tire. It is a figure which shows typically the side view of an example of a jig. It is a figure which shows typically the side view of an example of the jig at the time of taking out the resin member.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Pneumatic tire manufacturing method>
A method for manufacturing a pneumatic tire (hereinafter also simply referred to as a tire) according to an embodiment of the present invention will be described. FIG. 1 shows a cylindrical resin member 100. As shown in FIG. 1, in this embodiment, the resin member 100 has a circular arbitrary cross-sectional shape perpendicular to the axial direction. The cylindrical resin member 100 has a predetermined thickness (for example, 0.1 to 3.0 mm, although not particularly limited), and the predetermined thickness is equal to the thickness of the resin member 100 when the tire is completed. It can be substantially the same. Such a cylindrical resin member 100 can be formed by, for example, resin extrusion molding.

  Here, as the resin of the resin member 100, for example, a thermoplastic elastomer or a thermoplastic resin can be used, and a resin that is cross-linked by heat or an electron beam, or a resin that is cured by thermal dislocation can also be used. As thermoplastic elastomers, polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), polyester-based thermoplastic elastomer (TPC) And dynamic crosslinkable thermoplastic elastomer (TPV). Examples of the thermoplastic resin include polyurethane resin, polyolefin resin, vinyl chloride resin, polyamide resin and the like. Further, as the thermoplastic resin, for example, the deflection temperature under load (0.45 MPa load) specified in ISO 75-2 or ASTM D648 is 78 ° C. or more, and the tensile yield strength specified in JIS K7113 is A material having a tensile fracture elongation of 50% or more as defined in JIS K7113 and a Vicat softening temperature (Method A) as defined in JIS K7206 of 130 ° C. or more can be used. The tensile modulus of elasticity (specified in JIS K7113: 1995) of this resin is preferably 50 MPa or more. This is because steering stability and the like can be improved. Moreover, it is preferable that the tensile elasticity modulus of this resin shall be 1000 Mpa or less. It is because riding comfort etc. can be maintained favorable. Note that the resin here does not include rubber (an organic polymer substance exhibiting rubber elasticity at room temperature).

Next, as shown in FIG. 2, in this embodiment, the cylindrical resin member 100 is cut perpendicularly to the axial direction so as to have a predetermined width W in the axial direction. Here, the predetermined width W can be determined according to the width of the resin member 100 in the tire width direction when the tire is completed. The resin member 100 can be cut by any known method such as mechanical cutting or melting.
Thus, the cylindrical resin member 100 is prepared.

  Next, in this embodiment, the resin member 100 is deformed into a predetermined shape. FIG. 3 is a perspective view showing an example of a jig 200 used when the resin member 100 is deformed into a predetermined shape. As shown in FIG. 3, the jig 200 has a cylindrical shape. The jig 200 is formed by connecting a large number of rod-shaped members 200a whose longitudinal direction is the axial direction of the cylinder in the circumferential direction. The jig 200 (bar-shaped member 200a) can be made of, for example, aluminum.

  FIG. 4 is an enlarged perspective view showing a part of the jig 200. As shown in FIG. 4, the jig 200 is configured such that the inner surface thereof has a predetermined diameter difference in the axial direction (the diameter R is different). In the illustrated example, the diameter R gradually decreases from the axial center to the end.

  In this embodiment, heat is applied to the cut resin member 100 until it reaches a temperature near the melting point of the resin, and in this state, the resin member 100 is set on the inner surface of the jig 200 as shown in FIG. For this reason, it is necessary to make the diameter of the outer surface of the resin member 100 smaller than the diameter of the inner surface of the jig 200 (for example, by comparing the diameters at the same position in the axial direction).

  Then, as shown in FIG. 6, by pressing from the inner surface of the resin member 100 toward the radially outer side, the resin member 100 heated to near the melting point expands, and a part of FIG. As shown in an enlarged view, the shape of the resin member 100 (softened by heating) follows the shape of the inner surface of the jig 200.

  In this manner, the resin member 100 can be deformed into a predetermined shape (in this embodiment, a shape in which the diameter of the cylinder gradually decreases from the axial center to the end of the resin member 100).

  Next, in the present embodiment, a cord covered with a coating material is wound around the axis of the resin member 100 on the resin member 100 deformed into a predetermined shape. Thus, a so-called spiral belt can be easily formed using the resin member 100 as a base, and the spiral belt also has a predetermined shape (in this embodiment, from the center to the end in the width direction of the belt). (For example, a shape in which the outer diameter is gradually reduced).

  As an example, the belt may be a spiral belt in which a rubber-coated cord, in which the cord is covered with a coating rubber, is wound around the axis of the resin member 100, that is, around the axis of the tire. . As the cord, any known material can be used, for example, a steel cord can be used. The steel cord can be made of, for example, steel monofilament or stranded wire. Moreover, an organic fiber, carbon fiber, etc. can also be used for a cord. For example, nylon or the like can be used as the organic fiber, and a single fiber or a plurality of single fibers twisted together can be used. As the covering rubber, any known rubber material such as a rubber material usually used for belt coating rubber can be used.

  As another example, the belt may be a spiral belt in which a resin-coated cord whose cord is coated with a coating resin is spirally wound around the axis of the resin member 100, that is, around the axis of the tire. it can. Also in this case, any known material can be used for the cord, for example, a steel cord can be used. The steel cord can be made of, for example, steel monofilament or stranded wire. Moreover, an organic fiber, carbon fiber, etc. can also be used for a cord. For example, nylon or the like can be used as the organic fiber, and a single fiber or a plurality of single fibers twisted together can be used. The coating resin can be the same type of resin as the resin member 100, but a different resin may be used. The resin-coated cord can be formed, for example, by coating a molten coating resin on the outer peripheral side of the cord and solidifying by cooling.

  In the present embodiment, the tire molding process of other tire members is performed by a normal method (the order of the resin member 100 and the spiral belt molding process is not particularly limited, and can be performed according to the custom). And a normal tire vulcanization process is performed after that and a pneumatic tire is manufactured.

According to the method for manufacturing a pneumatic tire of the present embodiment, the cylindrical resin member 100 and the jig 200 are prepared, the cylindrical resin member 100 is deformed into a predetermined shape, and the deformed resin member 100 is used. By winding the cord coated with the coating material around the axis, the resin member 100 and the spiral belt can be easily formed in a predetermined shape (in this embodiment, from the center in the axial direction toward the end). Thus, the diameter R can be gradually reduced). For this reason, compared with the case where the base etc. which extrude the resin member 100 for every various shape of the resin member 100 and spiral belt according to a tire size, a tire structure, etc. are uniformly prepared, it is simple and low-cost. Can be manufactured. In addition, since the spiral belt can wind the covering cord with the resin member 100 as a base, the workability of the spiral belt winding process is excellent.
As described above, according to the pneumatic tire manufacturing method of the present embodiment, a predetermined diameter difference can be imparted to the belt by a simple method.

Next, another example of the step of deforming the resin member 100 into a predetermined shape will be described.
FIG. 8 is a perspective view showing another example of the jig 200. FIG. 9 is an enlarged perspective view showing a part of the jig 200. As shown in FIGS. 8 and 9, the jig 200 has a cylindrical shape. As shown in FIGS. 8 and 9, the jig 200 is formed by connecting a large number of rod-shaped members 200 a whose longitudinal direction is the axial direction of the cylinder in the circumferential direction. The jig 200 (bar-shaped member 200a) can be made of, for example, aluminum.

  As shown in FIGS. 8 and 9, the jig 200 is configured such that the outer surface thereof has a predetermined diameter difference in the axial direction (diameter R is different). In the illustrated example, the diameter R gradually decreases from the axial center to the end.

  In this embodiment, heat is applied to the cut resin member 100, and the resin member 100 is set on the outer surface of the jig 200 as shown in FIG. For this reason, it is preferable that the diameter of the inner surface of the resin member 100 is substantially the same as the diameter of the outer surface of the jig 200 (for example, the diameter at the same position in the axial direction) to facilitate fitting.

  Then, as shown in FIG. 11, the resin member 100 to which heat has been applied is thermally contracted by being placed at room temperature, for example, and is in close contact with the outer surface of the jig 200. As a result, as shown in a partially enlarged view in FIG. 12, the shape of the resin member 100 (softened by heating) follows the outer surface shape of the jig 200.

  Even in this case, the resin member 100 can be deformed into a predetermined shape (in this embodiment, a shape in which the diameter of the cylinder gradually decreases from the axial center to the end of the resin member 100).

  Even in this case, the cord covered with the coating material is then wound around the axis of the resin member 100 on the resin member 100 deformed into a predetermined shape. Accordingly, a so-called spiral belt can be easily formed using the resin member 100 as a base, and the spiral belt also has a predetermined shape (in this embodiment, from the center to the end in the belt width direction). Can be added.

And after performing another tire formation process by a normal method, a normal tire vulcanization process is performed and a pneumatic tire is manufactured.
Even in this case, a predetermined diameter difference can be given to the belt by a simple method.

  In the method for manufacturing a pneumatic tire of the present invention, it is preferable to prepare several types (for example, 3 to 10 types) of the cylindrical resin member 100. By preparing the cylindrical resin member 100 having three or more types of diameters, the cylindrical resin member 100 having an appropriate diameter is prepared according to the tire size and the like, and the resin member is obtained by heat and / or force. This is because it is possible to suppress a failure of the resin member 100 due to an unreasonable deformation while making the deformation easy by reducing the amount of deformation required when deforming 100. On the other hand, it is because it can be made still simpler and low-cost by setting it as ten types or less. For example, one type can be prepared for every 50 mm in diameter.

  In the method for manufacturing a pneumatic tire according to the present invention, the cross-sectional shape of the prepared cylindrical resin member 100 may be constant in the axial direction or may be changed in the axial direction. For example, the resin member 100 and the spiral belt may have various shapes, and are prepared instead of or in addition to providing the resin member 100 with the shape in the process of applying heat and / or force. In some cases, it may be preferable that the resin member 100 itself has a shape close to the expected shape, and when the cross-sectional shape is constant in the axial direction, the shape changes in the axial direction. Because there is also.

  Moreover, in the manufacturing method of the pneumatic tire of this invention, the cylindrical resin member 100 extended long to an axial direction is used for the tire width direction of the resin member 100 in the finished pneumatic tire like said embodiment. Depending on the width, it is preferable to include a step of cutting perpendicularly to the axial direction in order to ensure ease of manufacture. On the other hand, in the present invention, such a cutting process can be omitted by preparing a cylindrical resin member having a predetermined width in advance.

  On the other hand, in the method for manufacturing a pneumatic tire according to the present invention, it is preferable that the resin member 100 to be prepared is uniform in the circumferential direction (having no joined portions or steps). This is because the uniformity of the tire circumferential direction of the finished pneumatic tire can be improved, and the durability and riding comfort of the tire can be improved. For example, such a resin member 100 can be formed by pouring molten resin into a mold that is uniform in the circumferential direction (having no joints or steps), cooling and solidifying it, and taking it out in the axial direction.

In the pneumatic tire manufacturing method of the present invention, as in the above-described embodiment, the step of deforming the resin member 100 into a predetermined shape is preferably performed by applying heat and / or force to the resin member 100. . This is because the resin member 100 can be deformed into a predetermined shape by a simpler method.
In the present invention, when the resin member 100 is deformed into a predetermined shape, various methods other than the above can be employed. For example, a force can be applied to the cylindrical resin member 100 (without applying heat) so that the cylindrical resin member 100 is brought into close contact with a jig having a predetermined shape and is plastically deformed to have a shape that follows the predetermined shape of the jig. .

  In the method for manufacturing a pneumatic tire according to the present invention, the predetermined shape is preferably a shape in which the diameter of the cylinder is different in the axial direction of the cylindrical resin member 100 as in the above embodiment. . This is because a belt having a diameter difference in the tire width direction can be easily formed.

In the method for manufacturing a pneumatic tire according to the present invention, the predetermined shape is a size of the diameter of the cylinder at least in a part in the axial direction from the axial center to the end of the cylindrical resin member 100. Preferably, the shape gradually decreases. This is because a belt having a shape in which the diameter gradually decreases from the center in the tire width direction toward the end can be easily formed. For example, it may be advantageous to improve the uneven wear resistance of a tire that easily undergoes center wear.
On the other hand, in the pneumatic tire manufacturing method of the present invention, the predetermined shape is a shape in which the diameter of the cylinder gradually increases from the axial center to the end of the cylindrical resin member 100. Is also preferable. This is because according to this method, it is possible to easily form a belt having a shape in which the diameter gradually increases from the center in the tire width direction toward the end. For example, it may be advantageous to improve the uneven wear resistance of a tire that easily undergoes shoulder wear.
Furthermore, in the method for manufacturing a pneumatic tire of the present invention, the predetermined shape is not limited to these cases. For example, the diameter of the cylinder from the axial center to the end of the cylindrical resin member 100 is not limited. It can also be made into the shape which has one place or more each of the location where the magnitude | size of gradually decreases and the location which increases gradually.

<Pneumatic tire>
FIG. 13 is a schematic cross-sectional view in the tire width direction showing an example of a pneumatic tire manufactured using the method for manufacturing a pneumatic tire according to the embodiment. As shown in FIG. 13, the pneumatic tire 1 of the present embodiment (hereinafter also simply referred to as a tire) includes a carcass 3 straddling a bead core 2 a embedded in a pair of bead portions 2 in a toroidal shape. The tire 1 includes a belt 4 and a tread 5 in this order on the outer side in the tire radial direction of the crown portion of the carcass 3. As shown in FIG. 13, the tire 1 of the present embodiment has the same configuration between the half portions in the tire width direction with the tire equatorial plane CL as a boundary, but can also have an asymmetric configuration. .

  The tire 1 has a bead core 2a in which steel cords are bundled. The material and shape of the bead core are not particularly limited, or may have a structure without the bead core 2a. Moreover, in this embodiment, although the carcass 3 is comprised by the one carcass ply consisting of organic fiber, the material and the number of carcass plies are not particularly limited.

  The belt 4 is a spiral belt in a state where a rubber-coated cord in which a cord 4b is covered with a covering rubber 4a is spirally wound around a tire axis. The belt 4 has a diameter difference in the tire width direction. Specifically, the diameter gradually decreases from the center in the tire width direction toward the end. The belt 4 is preferably a single layer. It is because it is preferable from a viewpoint of weight reduction. Also in this case, the width of the belt 4 in the tire width direction can be, for example, 90 to 120% of the tire ground contact width. The thickness (maximum thickness) of the belt 4 is not particularly limited, but can be, for example, 0.3 to 3.5 mm.

  The belt 4 may be a spiral belt in a state in which a resin-coated cord in which the cord 4b is coated with the coating resin 4a is spirally wound around the tire axis. Also in this case, the belt 4 is preferably a single layer. It is because it is preferable from a viewpoint of weight reduction. The width of the belt 4 in the tire width direction can be 90 to 120% of the tire ground contact width, for example. The thickness (maximum thickness) of the belt 4 is not particularly limited, but can be, for example, 0.3 to 3.5 mm.

Here, “tire contact width” refers to the tire applied to the rim, where the tire is mounted on the applicable rim, filled with the specified internal pressure, and the outermost position in the tire width direction of the contact surface in the state where the maximum load is applied. Mounted on the rim, filled with the specified internal pressure, and defined as the distance in the tire width direction between the ground contact edges in a no-load state
In addition, other dimensions in the present specification are measured in a state in which a tire is mounted on an applicable rim, filled with a specified internal pressure, and in a no-load state.

  In this specification, “applicable rim” is an industrial standard effective in the area where tires are produced and used. In Japan, JATMA (Japan Automobile Tire Association) JATMA YEAR BOOK, in Europe, ETRTO (The European) STANDARDDS MANUAL of Tire and Rim Technical Organization, in the United States, YEAR BOOK of TRA (The Tire and Rim Association, Inc.) etc. Refers to the Measuring Rim, or the Design Rim in the TRA YEAR BOOK (ie, the "rim" above is the current size) In addition, it includes sizes that may be included in the above industry standards in the future.Examples of “sizes that will be described in the future” include those listed as “FUTURE DEVELOPMENTS” in the 2013 edition of ETRTO STANDARDDS MANUAL. However, in the case of a size not described in the industry standard, it means a rim having a width corresponding to the bead width of the tire. The “specified internal pressure” refers to an air pressure (maximum air pressure) corresponding to the tire maximum load capacity of the standard such as JATMA in a tire of an applicable size. In the case of a size not described in the industry standard, the “specified internal pressure” refers to an air pressure (maximum air pressure) corresponding to a maximum load capacity specified for each vehicle on which a tire is mounted. “Maximum load load” is the tire maximum load capacity of the standard such as JATMA for the tire of the applicable size, or, in the case of a size not described in the industry standard, the maximum load capacity defined for each vehicle on which the tire is mounted. Means the load corresponding to.

  Further, as shown in FIG. 13, the tire 1 includes a resin member 6 (100) continuously extending in the tire width direction, which is plate-shaped in this example, on the inner side in the tire radial direction of the belt 4. . In this embodiment, the resin member 6 (100) is disposed on the inner side in the tire radial direction of the belt 4, but the resin member 6 (100) may be disposed on the outer side in the tire radial direction of the belt 4. . As shown in FIG. 1, in the present embodiment, the width of the resin member 6 (100) in the tire width direction is larger than the width of the belt 4 in the tire width direction, but may be the same or smaller. The width of the resin member 6 (100) in the tire width direction can be, for example, 80 to 130% of the tire ground contact width. The resin member 6 (100) has a diameter difference in the tire width direction. Specifically, the diameter gradually decreases from the center in the tire width direction toward the end (for example, the end diameter R1 <the diameter R2 near the center). ). The belt 4 also has a difference in diameter in the tire width direction. Specifically, the diameter gradually decreases from the center in the tire width direction toward the end (for example, end diameter R3 <diameter R4 near the center).

The embodiment shown in FIG. 13 has circumferential main grooves 8 (four in the illustrated example) that continuously extend in the tire circumferential direction. In the present invention, the number of the circumferential main grooves 8 is not particularly limited, and the circumferential main grooves 8 may not be provided.
FIG. 14 is a diagram schematically illustrating a side view of an example of a jig. As shown in FIG. 14, in the jig 32, the rod-shaped members 32A whose inner peripheral side is longer than the outer peripheral side and rod-shaped members 32B whose outer peripheral side is longer than the inner peripheral side are alternately arranged in the circumferential direction. (In FIG. 14, for the sake of simplicity, the number of rod-like members 32A and 32B is smaller than that shown in FIGS. 5 and 10, etc.). FIG. 15 is a diagram schematically showing a side view of an example of a jig when the resin member is taken out. As shown in FIG. 15, the jig 32 is reduced in diameter by sliding one of the rod-like members 32A (P3) whose inner peripheral side is longer than the outer peripheral side inward in the radial direction, and the state shown in FIG. From this, the resin member can be removed.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment at all. For example, after the step of deforming the resin member 100 into a predetermined shape, and the step of winding a cord coated with a coating material around the axis of the resin member 100 on the resin member 100 deformed into the predetermined shape A step of joining two or more deformed resin members 100 in the axial direction may be further included. For example, by joining two deformed resin members 100 at a position that becomes the tire equatorial plane CL, for example, by making the two deformations different from each other, an asymmetric shape (for example, a diameter) A resin member 100 having a shape in which the difference is different between the half portions in the tire width direction can be obtained. At this time, the spiral belt wound around the resin member 100 also has a similar (for example, asymmetric) shape with the tire equatorial plane CL as a boundary.
As for the structure of the pneumatic tire, the resin member 6 (100) having a predetermined shape and the belt 4 wound around the axis on the resin member 6 (100) have shapes obtained through a vulcanization process or the like. Except for the point which is doing, it is not limited at all.

1: pneumatic tire, 2: bead part, 2a: bead core, 3: carcass,
4: belt, 4a: coating material (coating rubber, coating resin), 4b: cord,
5: Tread, 6: Resin member, 8: Circumferential main groove,
100: Resin member, 200: Jig CL: Tire equatorial plane

Claims (4)

A step of preparing a cylindrical resin member;
Transforming the resin member into a predetermined shape;
Forming a belt having the cord by winding a cord coated with a coating material around the axis of the resin member on the resin member deformed into the predetermined shape. The manufacturing method of a pneumatic tire.   The method for producing a pneumatic tire according to claim 1, wherein the step of deforming the resin member into the predetermined shape is performed by applying heat and / or force to the resin member.   The method for manufacturing a pneumatic tire according to claim 1 or 2, wherein the predetermined shape is a shape in which a diameter of the cylinder is different in an axial direction of the cylindrical resin member.   The method for manufacturing a pneumatic tire according to claim 3, wherein the predetermined shape is a shape in which a diameter of the cylinder gradually decreases from an axial center to an end of the cylindrical resin member.

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