JP5886129B2 - Vulcanization envelope - Google Patents

Description

  The present invention relates to a vulcanization envelope.

  When a vulcanized tread (Precured Tread) is vulcanized in a vulcanizing can with a tire attached to a base tire via unvulcanized rubber, a vulcanizing bag (envelope) for covering the tire is provided. It is disclosed (see Patent Document 1).

JP 2011-56793 A

  However, in the case of a radial tire for a passenger car in which the gauge of the vulcanized tread is thin, the outer appearance may be deteriorated by transferring the soot generated in the envelope to the tread during vulcanization. In order to vulcanize without generating such transfer of wrinkles, it is preferable to set the outer diameter of the envelope smaller than the outer diameter of the tire, but it becomes difficult to attach and detach the envelope to and from a wide tire. In order to facilitate this attachment / detachment operation, it is preferable to increase the outer diameter of the envelope, but an extra area increases and wrinkles are likely to occur.

  In view of the above facts, the present invention has an object to facilitate attachment / detachment to / from a tire while suppressing generation of wrinkles of an envelope.

The invention according to claim 1 is configured to be stretchable so that the tread portion of the tire and the side portions on both sides in the tire width direction can be covered from the outside of the tire, and the outer diameter of the maximum diameter portion in the tire diameter direction is that of the tire. It is set smaller than the outer diameter, is a three-dimensional configuration in the natural state, and the inner peripheral edges on both sides in the tire width direction are separated from each other.

  In the vulcanization envelope according to claim 1, since the maximum outer diameter in the tire diameter direction is set smaller than the outer diameter of the tire, generation of wrinkles at the time of mounting on the tire can be suppressed. Moreover, since the inner peripheral edges on both sides in the tire width direction are separated from each other in a natural state, the tire can be easily attached to and detached from the tire without increasing the maximum outer diameter of the envelope.

  According to a second aspect of the present invention, in the vulcanized envelope according to the first aspect, two rubber sheets each formed in an annular shape are bonded together.

  The vulcanized envelope according to claim 2 is easy to manufacture because the two rubber sheets each formed in an annular shape are bonded together.

  According to a third aspect of the present invention, in the vulcanized envelope according to the first or second aspect, the maximum diameter portion is offset from the center in the tire width direction to one side in the tire width direction.

  In the vulcanized envelope according to claim 3, since the maximum diameter portion is offset from the center in the tire width direction to one side in the tire width direction, the expansion force (shrinkage force) is asymmetric in the tire width direction. Yes. For this reason, attachment / detachment workability can be further improved by attaching / detaching to / from the tire from the side where the expansion force (contraction force) is small.

  As described above, according to the vulcanized envelope according to claim 1 of the present invention, it is possible to easily attach and detach the tire while suppressing generation of wrinkles of the envelope when the tire is attached to the tire. An excellent effect is obtained.

  According to the vulcanization envelope according to claim 2, an excellent effect that the production of the vulcanization envelope is facilitated can be obtained.

  According to the vulcanization envelope of the third aspect, it is possible to obtain an excellent effect that the detachability workability can be further improved.

(A) It is sectional drawing which shows typically the vulcanization envelope which concerns on 1st Embodiment. (B) It is sectional drawing which shows typically the vulcanization envelope which concerns on 2nd Embodiment. (C) It is sectional drawing which shows typically the vulcanization envelope which concerns on 3rd Embodiment. It is sectional drawing which shows typically the process of mounting | wearing a tire with the vulcanization envelope which concerns on 1st Embodiment. It is sectional drawing which shows typically the process of mounting | wearing a tire with the vulcanization envelope which concerns on 2nd Embodiment. It is sectional drawing which shows typically the process of mounting | wearing a tire with the vulcanization envelope which concerns on 3rd Embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[First Embodiment]
In FIG. 1 (A) and FIG. 2, the vulcanization envelope 10 according to the present embodiment has stretchability and is configured so that the tread portion 14 of the tire 12 and the side portions 16 on both sides in the tire width direction can be covered from the tire outer side. Has been. Here, the tire 12 is obtained by, for example, attaching a vulcanized tread (not shown) to a crown portion (not shown) of a base tire via an unvulcanized cushion rubber (not shown). .

  In the vulcanization envelope 10, the outer diameter D <b> 1 of the maximum diameter portion 18 in the tire diameter direction is set smaller than the outer diameter OD of the tire 12. The relationship between the outer diameters D1 and OD is preferably 0.8OD ≦ D1 <OD. When the value of the outer diameter D1 is less than this range, workability at the time of attaching / detaching the vulcanization envelope 10 to / from the tire 12 is deteriorated. Moreover, when the value of the outer diameter D1 exceeds this range, the frequency with which wrinkles are formed on the vulcanized tread increases.

  The vulcanization envelope 10 is configured by bonding two rubber sheets 24 and 26 each formed in an annular shape, for example, at the maximum diameter portion 18. The rubber sheets 24 and 26 are formed in a conical surface shape that gradually increases in diameter from the circular inner peripheral edge 22 toward the circular maximum diameter portion 18. Thereby, the vulcanization envelope 10 is formed in a V-shaped cross section. In addition, the code | symbol 28 in a figure is the sticking allowance 28 of the rubber sheets 24 and 26. FIG. The pasting allowance 28 is formed, for example, continuously or intermittently in the tire circumferential direction. Further, the pasting allowance 28 is formed to protrude on the inner peripheral side of the vulcanization envelope 10.

  In the natural state, the inner peripheral edges 22 on both sides in the tire width direction are separated from each other. A distance L1 from the maximum diameter portion 18 to the inner peripheral edge 22 in the tire width direction is greater than zero. The greater this distance L1, the better the workability when attaching / detaching the vulcanization envelope 10 to / from the tire 12, but it is preferably less than the tire half width (periphery) +100 mm, and no more is required.

  The inclination angle θ of the rubber sheet 24 with respect to the tire diameter direction is larger than O. However, from the viewpoint of suppressing the formation of wrinkles on the side portion 16 of the tire 12, the inclination angle θ is set such that the diameter D2 of the inner peripheral edge 22 is smaller than the rim diameter (not shown). Is desirable. The same applies to the rubber sheet 26.

  As a result, the vulcanization envelope 10 has a three-dimensional (three-dimensional) configuration having a thickness (≈2 × L1) in the tire width direction in a natural state. In other words, the vulcanization envelope 10 is not folded in a planar state in a natural state and is in a state where it is opened to some extent.

(Function)
This embodiment is configured as described above, and the operation thereof will be described below. In FIG. 1 (A), the vulcanization envelope 10 according to the present embodiment can be easily manufactured by laminating two rubber sheets each formed in an annular shape at the maximum diameter portion 18.

  In the vulcanized envelope 10, since the maximum outer diameter D1 in the tire diameter direction is set smaller than the outer diameter OD of the tire 12, slack due to the presence of an extra region is unlikely to occur. For this reason, generation | occurrence | production of the wrinkles at the time of mounting | wearing with the tire 12 can be suppressed. Therefore, it is possible to prevent the wrinkles of the vulcanization envelope 10 from being transferred to the tread portion 14 and to ensure good appearance of the tire 12 after vulcanization.

  Further, as shown in FIG. 1A, since the inner peripheral edges 22 on both sides in the tire width direction are separated from each other in the natural state, the attachment / detachment with respect to the tire 12 can be performed without increasing the maximum outer diameter D1 of the envelope. Can be easily performed. Specifically, as shown in FIG. 2, the vulcanization envelope 10 is open to some extent in the natural state, so one side of the vulcanization envelope 10 in the tire width direction (for example, the rubber sheet 24 side). It is easy to cover the tire 12 by spreading the inner peripheral edge 22 of FIG. Similarly, it is easy to remove the vulcanization envelope 10 from the tire 12 after vulcanization. Further, by not increasing the maximum outer diameter D1 of the envelope, the generation of wrinkles at the time of mounting on the tire 12 can be suppressed.

[Second Embodiment]
In FIG. 1 (B) and FIG. 3, the vulcanization envelope 20 according to the present embodiment has a cross-sectional shape formed into a quadratic function shape having the maximum diameter portion 18 as a local maximum point. In other words, the vulcanization envelope 20 is formed in a U-shaped cross section. Thereby, the vulcanization envelope 20 has a shape closer to the outer shape of the tire 12 than the vulcanization envelope 10 (FIG. 1A) according to the first embodiment in a natural state.

  Since other parts are the same as those in the first embodiment, the same parts are denoted by the same reference numerals in the drawings, and the description thereof is omitted.

(Function)
This embodiment is configured as described above, and the operation thereof will be described below. In FIG. 3, the vulcanization envelope 20 according to the present embodiment has a shape close to the outer shape of the tire 12 in a natural state, and therefore easily fits to the outer shape of the tire 12 when mounted on the tire 12. The attachment and detachment of the vulcanization envelope 20 with respect to the tire 12 can be easily performed by expanding the inner peripheral edge 22 on one side (for example, the rubber sheet 24 side) in the tire width direction in the arrow A direction.

[Third Embodiment]
1C and 4, in the vulcanization envelope 30 according to the present embodiment, the maximum diameter portion 18 is offset from the center C in the tire width direction to one side in the tire width direction. In the illustrated example, the maximum diameter portion 18 is offset to the left side of the drawing with respect to the center C in the tire width direction.

  The annular rubber sheet 24 is a portion that covers the side portion 16 on the left side of the sheet of the tire 12, and is formed planarly in a natural state. On the other hand, the annular rubber sheet 26 has an outer peripheral portion 26A that covers the tread portion 14 of the tire 12 and a side portion 26B that covers the side portion 16 on the right side of the paper, and is formed in a three-dimensional manner. . The rubber sheets 24 and 26 are configured to be bonded together at the end on the left side of the sheet. This portion is the maximum diameter portion 18 and the pasting allowance 28, and the pasting allowance 28 is formed so as to protrude on the outer peripheral side of the vulcanization envelope 30. Thereby, the vulcanization envelope 30 has a shape closer to the outer shape of the tire 12 than the vulcanization envelope 20 (FIG. 1B) according to the second embodiment in the natural state.

  The position of the maximum diameter portion 18 is not limited to the illustrated position. For example, the maximum diameter portion 18 may be offset to the end on the right side of the page, or may be disposed at an arbitrary position between the end on the left side of the page and the right end.

  Since other parts are the same as those in the first embodiment, the same parts are denoted by the same reference numerals in the drawings, and the description thereof is omitted.

(Function)
This embodiment is configured as described above, and the operation thereof will be described below. In FIG. 4, in the vulcanization envelope 30 according to the present embodiment, the maximum diameter portion 18 is offset from the center C in the tire width direction to one side in the tire width direction, so that the expansion force (shrinkage force) is the tire width. Asymmetric in direction. Further, since the vulcanization envelope 30 has a shape close to the outer shape of the tire 12 in a natural state, the vulcanized envelope 30 is easily fitted to the outer shape of the tire 12 when mounted on the tire 12. Therefore, the attachment / detachment of the vulcanization envelope 30 with respect to the tire 12 can be easily performed by expanding the inner peripheral edge 22 on the side having a small expansion force (contraction force), for example, the rubber sheet 24 side in the arrow A direction. For this reason, attachment / detachment workability can be further improved. Even if the tire 12 is a wide tire, the detachment workability of the vulcanization envelope 30 is good.

[Other Embodiments]
The vulcanization envelopes 10, 20, and 30 are not limited to the two rubber sheets 24 and 26 that are bonded together, and may be integrally formed from the beginning. In this case, there is no pasting allowance 28, and in the third embodiment, the outer peripheral portion 26A becomes the maximum diameter portion 18 as a whole.

10 Vulcanization envelope 12 Tire 14 Tread portion 16 Side portion 18 Maximum diameter portion 20 Vulcanization envelope 22 Inner peripheral edge 24 Rubber sheet 26 Rubber sheet 30 Vulcanization envelope D1 Maximum outer diameter OD Outer diameter

Claims (3)

It has elasticity and is configured to be able to cover the tire tread and side portions on both sides in the tire width direction from the outside of the tire, and the outer diameter of the maximum diameter portion in the tire diameter direction is set smaller than the outer diameter of the tire. A vulcanized envelope having a three-dimensional configuration in a natural state and having inner peripheral edges on both sides in the tire width direction spaced apart from each other.   The vulcanization envelope according to claim 1, wherein two rubber sheets each formed in an annular shape are bonded together.   The vulcanization envelope according to claim 1 or 2, wherein the maximum diameter portion is offset from the center in the tire width direction to one side in the tire width direction.