JP2006076396A - Regenerated pneumatic radial-ply tire for aircraft and split mould - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a regenerated pneumatic radial-ply tire for aircraft and split moulds, eliminating the risk of generation of a center dislocation or mould biting even in case the tire with the outside diameter expansion ratio dropped due to the enhancement of the anti-cut characteristic of the tread and improvement in wear characteristic of the tread is to be vulcanized, and suppressing the degradation of the tire surface property and the drop of the adhesive strength between the constituent members. <P>SOLUTION: The regenerated pneumatic radial-ply tire for aircraft has a plurality of belt layers formed from high resilient cords and not able to elongate in the tire circumferential direction, wherein the outside diameter expansion ratio ▵ϕ of the tire equator part when the specified internal pressure is supplied should be ▵ϕ≤3.0%, and the condition 1.5≤2d/D×100≤3.0 should be met, where D is the tire outside diameter at the time a tread moulded in advance is affixed, and d is the depth of at least one circumferentially stretching groove, and the tire tread is vulcanized by the split moulds. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pneumatic rehabilitated radial tire for aircraft and a split mold having a belt layer made of a highly elastic cord.

  Conventionally, a pneumatic radial tire for an aircraft in which a plurality of belt layers are provided below a tread portion is known (see Patent Document 1). When rehabilitating a tire such as that returned from a market run, the tread part of the tire is buffed (cut), and then a pre-formed tread is pasted so that the contact surface with the tread is in the tire axial direction. It was only divided and was vulcanized by a full mold that did not move in the tire radial direction. The completed tire is called a pneumatic retreaded radial tire for aircraft.

In recent years, it has been hoped to develop pneumatic retreaded radial tires for aircraft that have improved tread wear characteristics and improved tread cut resistance and lower outer diameter expansion than conventional tires without increasing the weight of the tire. It is rare.
WO 03/061991 Publication

  However, when a tire having a lower outer diameter expansion rate than conventional is vulcanized by a full mold, various problems have occurred compared to the case of vulcanizing a conventional tire having a higher outer diameter expansion rate.

  Specifically, when the clearance between the inner diameter of the full mold and the outer diameter of the tire is large, sufficient pressure is not applied between the retreading members, causing poor property on the tire surface and a decrease in adhesion between the retreading members. In addition, when the clearance between the inner diameter of the full mold and the outer diameter of the tire is small, the mold groove bottom contacts the tire, and the tire does not enter the mold, There have been problems such as occurrence of mold biting by being bitten by the divided pieces of the mold and deviation of the center between the mold and the tire.

  Therefore, in view of the above problems, the present invention provides a center deviation and a mold even in the case of vulcanizing a tire whose outer diameter expansion rate has decreased due to improved wear characteristics of the tread and improved cut resistance of the tread. It is an object of the present invention to provide a pneumatic rehabilitated radial tire for aircraft and a split mold that can suppress poor property on the surface of the tire and a decrease in adhesive strength between components without occurrence of biting.

  The first feature of the present invention is that the belt has a plurality of belt layers that are made of a highly elastic cord and are non-extensible in the tire circumferential direction, and the outer diameter expansion coefficient of the tire equator portion is Δφ. The outer diameter expansion rate when the inner pressure is filled is Δφ ≦ 3.0%, the tire outer diameter at the time when the pre-formed tread is pasted is D, and the depth of at least one circumferential groove is Is a pneumatic rehabilitated radial tire for aircraft, wherein 1.5 ≦ 2d / D × 100 ≦ 3.0 is satisfied, and the tire tread is vulcanized by a split mold. To do.

  According to the pneumatic retreaded radial tire for aircraft according to the first feature of the present invention, it is possible to improve the wear characteristics of the tread without increasing the tire weight, and to improve the cut resistance of the tread. By vulcanizing a simple tire with a split mold, it is possible to prevent center deviation and mold biting.

  A second feature of the present invention is a split mold used for vulcanizing a pneumatic rehabilitation radial tire for an aircraft, the contact surface with the tire tread is divided into a plurality of parts, and is movable in the tire radial direction. When the outer diameter expansion coefficient of the tire equator portion is Δφ and the outer diameter of the tire at the time when the pre-formed tread is pasted is D, 0.2 ≦ (D + Δφ / 100D−M) / D × The gist is a split mold having an inner diameter M satisfying 100.

  According to the split mold according to the second feature of the present invention, when vulcanizing an aircraft pneumatic regenerative radial tire that improves the wear characteristics of the tread without increasing the tire weight and improves the cut resistance of the tread. Since sufficient pressure can be applied between the retreaded members of the base tire and the tread, the tire surface property can be improved and the adhesive force between the retreaded members can be further strengthened.

  According to the present invention, even when vulcanizing a tire having a reduced outer diameter expansion rate due to improved tread wear characteristics and improved tread cut resistance, center deviation and mold biting do not occur. Further, it is possible to provide a pneumatic rehabilitation radial tire for aircraft and a split mold that can suppress poor property on the tire surface and a decrease in adhesive strength between components.

  Below, the structure of the tire and split mold which concern on this embodiment is demonstrated.

  FIG. 1 is a cross-sectional view showing an aircraft pneumatic renewal radial tire 10 according to the present embodiment. Note that the pneumatic retreaded radial tire 10 for an aircraft (hereinafter, the tire body 10) is a tread formed by buffing (shaping) the tread portion 1 of the base tire 15 that has been returned from market travel and has been used. This is a tire vulcanized and vulcanized.

  The tire body 10 includes a pair of bead portions 4, a pair of sidewall portions 3, a tread portion 1 straddling the sidewall portions 3, and a belt portion including a plurality of spiral belt layers provided below the tread portion 1. 2 are provided.

  The plurality of spiral belt layers constituting the belt portion 2 is formed of an organic fiber cord having a tensile strength of 1500 MPa or more and has non-stretchability in the tire circumferential direction.

  When at least one circumferential groove 5 having a depth d is formed in the tread portion 1 and the tire outer diameter at the time when the preformed tread of the tire body 10 is pasted is D, 5 ≦ 2d / D × 100 ≦ 3.0 is satisfied.

  The prescribed standard rim 5 suitable for the tire body 10 is a standard rim having a dimension determined by a predetermined standard on which the tire body 10 is to be assembled. The standard rim applied here conforms to an industry standard (for example, “TRA Year Book” in the United States of America) for each region where the tire body 10 is produced or used.

  FIG. 2 is a cross-sectional view showing the outer diameter expansion rate of the base tire 15 in the present embodiment.

  In the figure, a tire A showing only the left half shows the base tire 15 when the internal pressure is 0 kPa, and a tire B showing only the right half shows the base tire 15 when the specified internal pressure is filled. ing. Here, the specified internal pressure is an internal pressure specified by TRA.

  The outer diameter of the tire A is Da, the outer diameter of the tire B is Db, and the outer diameter expansion coefficient of the central portion of the base tire 15 is 3% or less. Here, the outer diameter expansion coefficient is calculated by (Db−Da) / Da × 100.

  FIG. 3 is a cross-sectional view showing a split mold 20 for vulcanizing the tire body 10 in the present embodiment.

  FIG. 3A is a cross-sectional view showing a state in which the split mold 20 is opened. Here, the split mold 20 is a mold in which the contact surface with the tread portion 1 is divided into a plurality of parts and is movable in the tire radial direction (hereinafter, A direction). Further, when the inner diameter of the split mold 20 is M and the outer diameter of the tire body 10 at the time when the pre-formed tread is pasted is D, 0.2 ≦ (D + Δφ / 100D−M) / D × 100 is established. The inner diameter of the split mold 20 is the inner diameter at the center portion when the split mold 20 is closed.

  The split mold 20 shown in FIG. 1 includes an upper mold 21, a lower mold 22, a tread upper mold 23, and a tread lower mold 24.

  The upper mold 21 is provided with a vertical side 21a that pushes a tread upper mold 23, which will be described later, in the A direction, and a horizontal side 21b that applies pressure to the corresponding one of the sidewall portions 3.

  The lower mold 22 is provided with a vertical side 22a that pushes a tread lower mold 24, which will be described later, in the A direction, and a horizontal side 22b that applies pressure to the corresponding other sidewall portion 3.

  The tread upper mold 23 and the tread lower mold 24 are provided with projecting portions 23a and 24a for forming the circumferential grooves 5 in the tread portion 1 on the space 30 side described later. Further, the number of the protrusions 23a and 24a corresponds to the circumferential grooves 5 to be formed.

  In the state where the split mold 20 is open, a space 30 is formed, and the tire body 10 is disposed in the space 30.

  FIG. 3B is a cross-sectional view showing a state where the split mold 20 is closed.

  As shown in the figure, when the upper die 21 moves in the C direction, the vertical side 21a of the upper die 21 pushes the tread upper die 23 in the A direction, so that the tread upper die 23 is closed together with the upper die 21. Further, since the lower mold 22 moves in the B direction, the vertical side 22a of the lower mold 22 pushes the tread lower mold 24 in the A direction, so that the tread lower mold 24 is closed together with the lower mold 22. By closing the split mold 20, the lateral side 21 b of the upper mold 21 and the lateral side 22 b of the lower mold 22 apply pressure to the sidewall portion 3. Further, the protrusions 23 a and 24 a provided on the tread upper mold 23 and the tread lower mold 24 apply pressure to the tread portion 1 of the tire body 10 to form a tread pattern such as the circumferential groove 5 on the tread portion 1. Here, the split mold 20 vulcanizes the tire body 10.

(Operation / Effect of Aircraft Pneumatic Construct Radial Tire and Split Mold According to this Embodiment)
According to the pneumatic retreaded radial tire 10 for aircraft according to the present embodiment, the tire has a plurality of belt layers that are configured by high elastic cords and are non-extensible in the tire circumferential direction, and the outer diameter expansion coefficient of the tire equator line portion is increased. In the case of Δφ, the outer diameter expansion rate when the specified internal pressure is filled is Δφ ≦ 3.0%, the tire outer diameter is D, and the depth of at least one circumferential groove is d In this case, since 1.5 ≦ 2d / D × 100 ≦ 3.0 is satisfied and the tire tread is vulcanized by the split mold, the wear characteristics of the tread are improved without increasing the tire weight, and the tread is cut resistant. Further, by vulcanizing the tire as described above with a split mold, it is possible to prevent the center deviation and mold biting.

  In addition, according to the split mold 20 according to the present embodiment, the contact surface with the tire tread is divided into a plurality of parts and is movable in the tire radial direction. When the tire outer diameter at the time when the applied tread is attached is D, the tire has an inner diameter M that satisfies 0.2 ≦ (D + Δφ / 100D−M) / D × 100. Since sufficient pressure can be applied between the members, the tire surface properties can be improved, and the adhesive force between the retreaded members can be further strengthened.

  Example 1 of the pneumatic retreaded radial tire for aircraft and the split mold 20 according to the embodiment of the present invention will be described in detail below.

  As shown in Table 1, tires of Example 1 and Conventional Example 1 were manufactured, Example 1 was vulcanized with a split mold, Conventional Example 1 was vulcanized with a full mold, and mold biting occurred. The presence or absence of was investigated.

In addition, the size of the pneumatic rehabilitation radial tire for aircraft was 1270X455R22.

  From the results shown in Table 1, when a pneumatic retreaded radial tire reinforced with an inextensible belt layer in the tire circumferential direction is vulcanized with a full mold, mold biting occurs, and the product Although the center shift occurred, it was found that mold biting did not occur when vulcanized with a split mold.

  Example 2 of the pneumatic retreaded radial tire for aircraft and the split mold 20 according to the embodiment of the present invention will be described in detail below.

As shown in Table 1, tire surface properties after producing tires of Example 2, Example 3 and Comparative Example 1, changing only the outer diameter of the tire after retread tread molding, and vulcanizing each with a split mold And the adhesive force between rehabilitation members was examined. In addition, about the adhesive force between rehabilitation members, it has displayed with the index | exponent, and it has shown that there exists adhesive force, so that a numerical value is high. In addition, the size of the pneumatic retreaded radial tire for aircraft was 1270 × 455R22.

  From the results of Table 2, in Comparative Example 1 that does not satisfy 0.2 ≦ (D + Δφ / 100D−M) / D × 100, the tire surface properties and the adhesive force between the retreaded members are reduced. As shown in Example 3, when 1.5 ≦ 2d / D × 100 ≦ 3.0 and 0.2 ≦ (D + Δφ / 100D−M) / D × 100 are satisfied, tire surface properties and rehabilitation It was found that the adhesion between the members was good.

It is sectional drawing which shows the pneumatic rehabilitation radial tire for aircraft which concerns on embodiment of this invention. It is sectional drawing which shows the outer diameter expansion coefficient of the base tire which concerns on embodiment of this invention. It is sectional drawing which shows the split mold which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Tread part 2 ... Belt part 3 ... Side wall part 4 ... Bead part 5 ... Circumferential groove | channel 10 ... Pneumatic rehabilitation radial tire for tires (tire body)
DESCRIPTION OF SYMBOLS 15 ... Base tire 20 ... Split mold 21 ... Upper mold | type 21a ... Vertical side 21b ... Horizontal side 22 ... Lower mold | type 22a ... Vertical side 22b ... Horizontal side 23 ... Tread upper type | mold 23a ... Protrusion part 24 ... Tread lower type | mold 24a ... Protrusion part 30 ... space

Claims (2)

Consists of a high elastic cord, having a plurality of belt layers that are non-extensible in the tire circumferential direction,
When the outer diameter expansion coefficient of the tire equator line portion is Δφ, the outer diameter expansion coefficient when the specified internal pressure is filled is Δφ ≦ 3.0%,
When the tire outer diameter at the time when the pre-formed tread is pasted is D, and the depth of at least one circumferential groove is d, 1.5 ≦ 2d / D × 100 ≦ 3.0 is satisfied,
A pneumatic retreaded radial tire for aircraft, wherein the tire tread is vulcanized by a split mold. A split mold used for vulcanization of pneumatic retreaded radial tires for aircraft,
The contact surface with the tire tread is divided into multiple parts,
It can move in the tire radial direction,
When the outer diameter expansion coefficient of the tire equator portion is Δφ and the outer diameter of the tire at the time when the pre-formed tread is pasted is D, 0.2 ≦ (D + Δφ / 100D−M) / D × A split mold having an inner diameter M satisfying 100.

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