JP4810982B2 - Pneumatic tire manufacturing method - Google Patents

Description

The present invention relates to a method of manufacturing a pneumatic tire using the tire vulcanizing mold, and more particularly relates to a method of manufacturing a pneumatic tire can readily determine the pressure conditions at the time of the green tire upset.

  In general, in a vulcanization process, a pneumatic tire is set in a mold attached to a tire vulcanizer, and then the bladder is inflated to expand the diameter of the set green tire, and the molding surface inside the mold Vulcanization is performed in a state where it is pressed against. Conventionally, various molds have been proposed as tire vulcanization molds used in such a vulcanization process (see, for example, Patent Documents 1, 2, and 3).

  By the way, in vulcanization using a bladder or the like, due to the difference in the tire structure, the shoulder portions of the tread portion of the green tire may be pressed against the molding surface inside the mold before the center portion when the diameter of the green tire is expanded. . In the tire molded in this way, both ends of the reinforcing layer (belt layer, etc.) arranged in the tread portion are pressed first, so that the angle of the cord of the reinforcing layer is shouldered in the vulcanized tire. The tire part is different from the center part and adversely affects the tire performance.

  Conventionally, this problem can be solved by gradually increasing the pressure applied in the bladder. However, when the pressurization speed is slow, the vulcanization time is increased correspondingly and the productivity is lowered. Therefore, in the newly developed tire, when determining the pressurizing conditions when the green tire is inflated, various test tires were vulcanized by varying the internal pressure of the bladder, and the test tire was cut and reinforced. By examining the state of the above, the situation where the shoulder portion and the center portion are pressed against each other is determined, and based on that, an appropriate pressurizing condition that does not cause the above problem is determined while suppressing an increase in the vulcanization time as much as possible. .

However, there is a problem that the work is complicated and a large number of tires are wasted, and countermeasures have been strongly demanded.
JP 2005-145024 A JP 2005-161546 A JP 2005-161609 A

The objective of this invention is providing the manufacturing method of the pneumatic tire which can determine the pressurization conditions at the time of green tire expansion diameter easily.

The manufacturing method of the pneumatic tire of the present invention that achieves the above object includes a center molding region of a tread molding surface that molds a center portion of a tread portion of a green tire, and a tread that molds both shoulder portions of the tread portion of the green tire. Use tire vulcanization molds with sensors that detect contact of the green tire with the tread molding surface in both shoulder molding areas of the molding surface, and set the green tire in the tire vulcanization mold The green tire is inflated inside the set green tire, and the green tire is inflated by the inflating bladder and pressed against the molding surface of the tire vulcanization mold, while the green tire is vulcanized. The part where the green tire contacts the molding surface of the tire vulcanization mold based on the contact between the tire and each sensor And detecting the sequence and its time difference.

  According to the present invention described above, in the center molding region and both shoulder molding regions of the tread molding surface of the tire vulcanization mold, by installing sensors for detecting that the green tire has contacted the tread molding surface, The order and time difference in which the shoulder portion and the center portion of the green tire come into contact with the tread molding surface at the time of expansion can be easily known. Therefore, in a tire having a newly developed structure, it is possible to easily determine the pressurizing condition at the time of expanding the green tire without causing the conventional troublesome work and waste of the tire.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an embodiment of a tire vulcanizing mold according to the present invention. This mold M has annular upper and lower molds 1 and 2 and an annular side mold 3 disposed therebetween. .

  The upper mold 1 has a sidewall molding surface 1a for molding one sidewall portion T1 of the green tire T on the lower surface. The lower mold 2 includes a sidewall molding surface 2a for molding the other sidewall portion T2 of the green tire T on the upper surface. The side mold 3 includes a plurality of sectors 3X arranged in an annular shape, and each sector 3X includes a tread molding surface 3Xa for molding the tread portion T3 of the green tire T on the inner peripheral side. Upper and lower bead rings 4 and 5 for molding both bead portions T4 and T5 of the green tire T are provided on the inner peripheral side of the upper mold 1 and the lower mold 2.

  A plurality of sensors 6 (6a, 6b, 6c) that detect that the green tire T has contacted the tread molding surface 3Xa are embedded in the tread molding surface 3Xa of one sector 3X so as to be exposed to the tread molding surface 3Xa. ing. The center molding region 3Xc of the tread molding surface 3Xa for molding the center portion T3c of the tread portion T3 of the green tire T and the both shoulder molding regions 3Xs of the tread molding surface 3Xa for molding both shoulder portions T3s of the tread portion T3c of the green tire T One sensor 6 is arranged in each.

  Further, the side wall molding surfaces 1a and 2a of the upper mold 1 and the lower mold 2 for molding the side wall portions T1 and T2 of the green tire T, and the bead rings 4 and 5 for molding the bead portions T4 and T5 of the green tire T, respectively. The bead molding surfaces 4a and 5a are also arranged so that the sensor 6 is exposed on the surface.

  In the figure, 11 is a carcass layer extending between the bead portions T4 and T5 of the green tire T, and 12 is a belt layer (reinforcing layer) disposed on the outer peripheral side of the carcass layer 11 of the tread portion T3.

  In the pneumatic tire, the green tire T is set in the mold M, and the set green tire T is inflated by the bladder 7 and pressed against the molding surfaces 1a, 2a, 3Xa inside the mold M (see FIG. 1). State) Manufactured by vulcanization. At that time, when the internal pressure is applied and the green tire T, which is pressed by the expanding bladder 7 and expands in diameter, comes into contact with the sensor 6 provided on the molding surface, the sensor 6 is turned on and the green tire T comes into contact with the molding surface. Let them know. Therefore, by knowing the order in which the sensor 6 is turned on, it is easy to know from which part the green tire T starts to contact the molding surface, and it is also possible to know the difference in contact time.

  For example, when the sensor 6a arranged in the center molding region 3Xc is turned on after 10 seconds and the sensors 6b and 6c arranged in the shoulder molding region 3Xs are turned on after 12 seconds, the center of the tread portion T3 of the green tire T is set. It can be seen that the portion T3c contacts the tread molding surface 3Xa first, and the time difference of contact is 2 seconds.

  Further, when the sensors 6b and 6c arranged in the shoulder molding region 3Xs are turned on after 11 seconds and the sensor 6a arranged in the center molding region 3Xc is turned on after 12 seconds, both the tread portions T3c of the green tire T are It can be seen that the shoulder portion T3s first contacts the tread molding surface 3Xa, and the contact time difference is 1 second.

  As described above, in the present invention, the sensors 6a, 6b, and 6c for detecting that the green tire T is in contact with the tread molding surface 3Xa are disposed in the center molding region 3Xc and the shoulder molding regions 3Xs of the tread molding surface 3Xa. It is possible to easily know the situation (order and time difference) where the shoulder portion T3s and the center portion T3c of the green tire T are pressed against the tread molding surface 3Xa at the time of expansion. Therefore, in the tire having a newly developed structure, it is possible to easily determine the pressurizing condition when the green tire T is inflated without causing conventional troublesome work and tire waste.

  In the present invention, the sensor 6 is preferably composed of a pressure sensor capable of detecting the contact pressure of the green tire T. Thereby, since the contact state (contact pressure) of the green tire T during vulcanization can also be known, the vulcanization condition (vulcanization time) based on the contact state in addition to the pressurizing condition at the time of expansion described above. , Vulcanization pressure, vulcanization temperature) can be set, thereby enabling proper vulcanization, so that the rubber physical properties of the vulcanized tire can be improved and the durability can be improved.

  As the pressure sensor used for the sensor 6, a sensor that detects the contact pressure of the green tire T by a change in resistance of the pressure-sensitive conductive rubber can be preferably used. When placing the sensing element of the pressure sensor so as to be flush with the curved molding surface, the pressure sensing rubber can be used to make the sensing element follow the molding surface easily. The rubber flow is not obstructed. The size of the pressure-sensitive conductive rubber is preferably 5 mm or more in consideration of the deformation speed of the rubber. The upper limit value is not particularly limited as long as the upper limit value can be set between the groove molding bones K protruding from the molding surface.

  The side wall molding surfaces 1a and 2a of the upper mold 1 and the lower mold 2 and the sensors 6 of the bead molding surfaces 4a and 5a of the bead rings 4 and 5 need to be particularly arranged in order to achieve the object of the present invention described above. However, it is preferable to use a pressure sensor for the sensor 6 as described above and to set the vulcanization conditions based on the contact state. In that case, what is necessary is just to arrange | position to the bead molding surfaces 4a and 5a of the side wall molding surfaces 1a and 2a and / or the bead rings 4 and 5 as needed.

  In the above embodiment, one sensor 6 is arranged in the circumferential direction, but a plurality of sensors 6 may be arranged in the circumferential direction as necessary. The sensors 6a, 6b and 6c are arranged in the same sector 3X, but may be arranged in different sectors 3X.

  The tire vulcanization mold M of the present invention can be suitably used when setting the pressure condition and vulcanization condition at the time of expansion as described above, but is not limited to this, and the tire is regularly used. It can also be preferably used when checking the pressurizing condition and vulcanizing condition at the time of expansion. Naturally, it can also be used as a tire vulcanization mold that is always used.

  The present invention is not limited to the sectional type tire vulcanizing mold having the upper mold 1, the lower mold 2, and the side mold 3 described above, and one half of the green tire is molded without having the side mold. Alternatively, a tire vulcanization mold having a two-part structure including an upper mold and a lower mold for molding the other half may be used.

1 is a half cross-sectional view showing an embodiment of a tire vulcanization mold according to the present invention.

Explanation of symbols

1 Upper mold 1a Side wall molding surface 2 Lower mold 2a Side wall molding surface 3 Side mold 3X Sector 3Xa Tread molding surface 3Xc Center molding area 3Xs Shoulder molding area 4, 5 Bead ring 6, 6a, 6b, 6c Sensor M Tire vulcanization Mold T Green tire T1, T2 Side wall T3 Tread T3c Center T3s Shoulder T4, T5 Bead

Claims (4)

The green tire is the tread molding surface in the center molding region of the tread molding surface that molds the center portion of the tread portion of the green tire and the both shoulder molding region of the tread molding surface that molds both shoulder portions of the tread portion of the green tire. Using tire vulcanization molds with sensors for detecting contact , green tires are set in the tire vulcanization molds, and a bladder is inflated inside the set green tires. The green tire is inflated by an inflating bladder and pressed against the molding surface of the tire vulcanization mold to vulcanize the green tire, while the green tire is in contact with the tire based on contact between the green tire and each sensor. A pneumatic cylinder characterized by detecting the order of the parts contacting the molding surface of the vulcanizing mold and the time difference between them. Manufacturing method of ya. The method for manufacturing a pneumatic tire according to claim 1, wherein the sensor is a pressure sensor capable of detecting a contact pressure of the green tire. The method for manufacturing a pneumatic tire according to claim 2, wherein the pressure sensor is configured to detect a contact pressure of the green tire by a resistance change of the pressure-sensitive conductive rubber. The pneumatic tire according to claim 1, 2, or 3, wherein the sensor is further arranged on a sidewall molding surface for molding a sidewall portion of a green tire and / or a bead molding surface for molding a bead portion of a green tire. Way .

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