JP5739748B2 - Tire manufacturing method - Google Patents

Description

  The present invention relates to a tire manufacturing method including a cooling step capable of quickly cooling a rigid core that is integrally taken out from a vulcanization mold with a vulcanized tire.

  In recent years, in order to improve the formation accuracy of a pneumatic tire, as shown in FIG. 10 (B), a rigid core a having an outer shape corresponding to the inner shape of the tire is used, and an inner liner, A tire component such as a carcass ply, a belt ply, a sidewall rubber, and a tread rubber is sequentially attached to form a raw tire T. The raw tire T is put together with the rigid core a into the vulcanization mold b. There has been proposed a vulcanization molding method in which a tire is sandwiched between a rigid core a that is an inner mold and a vulcanization mold b that is an outer mold (see, for example, Patent Document 1).

  In this method, after the vulcanization molding is completed, the rigid core a and the vulcanized tire are taken out from the vulcanization mold b in an integrated state. It is in a high temperature state of 190 ° C.

  Therefore, when left in this integrated state (natural cooling), the vulcanized tire may be overvulcanized by the heat of the rigid core a, and the tire quality may be deteriorated. Therefore, it is required to disassemble the rigid core a and remove it from the vulcanized tire as soon as possible.

  As shown in FIG. 10A, the rigid core a has a core body a1 formed by a plurality of core segments c divided in the tire circumferential direction. Specifically, the first core segment c1 in which the split surfaces at both ends in the circumferential direction incline in the direction in which the circumferential width decreases toward the inside in the radial direction, and the first core segment c1 are in the circumferential direction. In addition, the split surfaces at both ends in the circumferential direction are alternately formed with second core segments c2 that incline in a direction in which the circumferential width increases inward in the radial direction. Then, the core body a1 can be disassembled and taken out from the bead hole of the vulcanized tire by sequentially moving inward in the radial direction from the second core segment c2.

  However, when the core body a1 is in a high temperature state as described above, it is difficult to disassemble because the core segments c mesh with each other due to thermal expansion. Cooling is done by spraying on sulfur tires.

  However, in such a cooling method, it takes about 2 to 3 hours to cool the core body a1 to a temperature at which the core body a1 can be decomposed (for example, 80 to 100 ° C.). It is enough. This cooling delay also adversely affects tire production efficiency.

JP 2006-160236 A

  Therefore, the present invention is based on spraying fine mist of water on the outer surface of the vulcanized tire and the exposed surface of the core body, respectively, so that the core body and the vulcanized tire are not wetted with the core body. An object of the present invention is to provide a production method that can rapidly cool, suppress overvulcanization of the tire, and improve the production efficiency of the tire.

In order to solve the above-mentioned problem, the invention of claim 1 of the present application uses the rigid core having a decomposable hollow toroidal core body composed of a plurality of core segments divided in the tire circumferential direction. A green tire forming process for forming a green tire on the outer surface of the core body,
A vulcanization step in which the raw tire is put together with a rigid core into a vulcanization mold to heat vulcanize the raw tire;
A cooling step of cooling the rigid core with the vulcanized tire taken out from the vulcanization mold,
The cooling step, the water of a fine mist, and a tire spray sprayed onto the outer surface of the vulcanized tire, Ri Do from the core spray for spraying on the exposed surface of the core body,
The tire spray has a substantially circular pattern as the spray pattern of the fine mist,
The core spray is characterized in that the spray pattern of the fine mist is a flat pattern that is long in the tire circumferential direction .

In the invention according to claim 2, the tire spray is performed by tread cooling for spraying the fine mist at a plurality of positions in the tire circumferential direction on the outer surface of the tread portion of the vulcanized tire, and the tire on the outer surfaces of both sidewall portions. Including a sidewall cooling that sprays the fine mist at a plurality of positions in the circumferential direction ,
The core spray, a plurality of positions in the tire circumferential direction on the exposed surface of the core body, is characterized in the spray to Turkey the fine mist.

  As described above, according to the present invention, fine mist of water is applied to the outer surface of the vulcanized tire and the exposed surface of the core body with respect to the rigid core with the vulcanized tire taken out from the vulcanization mold. The cooling process to spray is performed. Such a fine mist is caused by water droplets evaporating in the air stream and the temperature of the air stream itself decreasing, and water droplets colliding with the tire or core body and evaporating on the surface to take away latent heat, etc. Compared with cold air cooling, the cooling effect can be greatly improved.

  In particular, since the fine mist is sprayed directly on the exposed surface of the core body, the cooling effect on the core body can be further enhanced. Moreover, since the fine mist evaporates quickly after colliding with the vulcanized tire and the core body, the surface thereof is not substantially wetted. Therefore, even if sprayed directly on the core body, stable and safe cooling can be performed without wetting the electric heater for vulcanization heating housed in the core body and the electrical circuit that is the wiring portion thereof. .

  Furthermore, because the cooling process is differentiated between tire spraying and core spraying, the spray amount and spraying time of fine mist are controlled separately for vulcanized tires and core bodies with different thermal conductivity and heat capacity. Therefore, it is possible to perform a well-balanced cooling such as adjusting the respective cooling rates.

It is sectional drawing which shows the raw tire formation process in the manufacturing method of the tire of this invention. It is a disassembled perspective view which shows the rigid core used for it. It is the side view which looked at the core main body from the axial direction. It is sectional drawing which shows a vulcanization | cure process. It is sectional drawing which shows a cooling process. It is the side view which looked at the cooling process from the axial center direction. (A) and (B) are the perspective view and front view which show the spray pattern of the fine mist in tire spray. (A) and (B) are the perspective view and front view which show the spray pattern of the fine mist in core spray. It is a graph which shows the time change of the internal temperature of the core main body by a test. (A) is the side view which looked at the conventional rigid core from the axial center direction, (A) is sectional drawing which shows the formation method of the pneumatic tire using the rigid core.

  Hereinafter, embodiments of the present invention will be described in detail. The present invention is a method of manufacturing a tire using a rigid core 1, and includes a green tire forming step S1, a vulcanizing step S2, and a cooling step S3.

  As shown in FIG. 1, in the green tire forming step S <b> 1, a green tire T is formed on the outer surface of the core body 2 of the rigid core 1. The rigid core 1 includes a core main body 2 having a tire molding surface J on the outer surface, and an inner liner, a carcass ply, a belt ply, The raw tire T is formed by sequentially attaching tire constituent members such as sidewall rubber and tread rubber.

  As shown in FIGS. 1 and 2, the rigid core 1 of this example includes the core body 2, a cylindrical core 4 inserted in the center hole 2 </ b> H of the core body 2, and the core body 2. A pair of side plates 5L, 5U disposed on both sides in the axial direction.

  The core body 2 has a tapered surface 6 that is inclined radially outward inward in the axial direction at the radially inner end of the toroidal main portion 2A having the tire molding surface J. A bulging portion 2B bulging outward in the direction is provided. The core body 2 is formed with a lumen 7 concentric with the core body 2, and a heating means 8 such as an electric heater for heating the raw tire T inside the lumen 7. Is arranged.

  The core body 2 is formed of a plurality of core segments 9 divided in the tire circumferential direction, as shown in FIGS. The core segment 9 includes a first core segment 9A in which the dividing surfaces 9S at both ends in the circumferential direction are inclined in a direction in which the circumferential width decreases inward in the radial direction, and the first core segment 9A. Is composed of second core segments 9B that are alternately arranged in the circumferential direction and in which the dividing surfaces 9S at both ends in the circumferential direction are inclined inward in the radial direction so that the circumferential width increases. Thereby, the core segment 9 can move the second core segment 9B radially inward, and after this movement, the first core segment 9A can also be sequentially moved radially inward. . In the core body 2, as in the conventional case, the core body 2 can be sequentially moved radially inward from the second core segment 9 </ b> B and sequentially taken out from the bead hole of the tire.

  The core 4 has a cylindrical shape, and is inserted into the center hole 2H of the core body 2 to prevent the core segments 9 from moving inward in the radial direction. One end of the core 4 in the axial direction is fixed to the inner surface of the side plate 5L on the one axial side by using, for example, a bolt. The side plate 5L on one side has a flange portion 11 that contacts the tapered surface 6 of the core body 2 so that the side plate 5L and the core body 2 can be aligned concentrically.

  In addition, in this example, the core 4 has an inner screw portion 13 on the other side in the axial direction of the center hole 4H, and a dovetail groove 14 extending continuously in the axial direction on the outer peripheral surface of the core 4. Alternatively, the first ant joint portion 16 made of one of the ant tenons 15 is formed. Further, on the inner peripheral surface of each core segment 9, a second dovetail portion 17 comprising the other of the dovetail groove 14 or the dovetail tenon 15 extending in the axial direction and engaging with the first dovetail portion 16. Is formed.

  Further, the side plate 5U on the other side in the axial direction also has a flange portion 11 that can be concentrically aligned by contacting the tapered surface 6 of the core body 2, and the inner surface of the side plate 5U has the core 4 on the inner surface. A boss portion 20 that can be detachably screwed to the inner screw portion 13 provided in the center hole 4H is projected. Further, a support shaft portion 12 is projected from the outer surface of the side plates 5L, 5U on the one side and the other side. For example, the support shaft portion 12 holds the rigid core 1 by a conveying device and conveys it to a raw tire forming machine or a vulcanization mold, or the conveyed rigid core 1 is a raw tire forming machine, It functions as a mounting part for mounting on vulcanizing molds, cooling devices, and the like. In addition, the chuck portion 21 of the conveying device that holds the support shaft portion 12 or the chuck portion 21 such as a green tire forming machine, a vulcanization mold, and a cooling device to which the support shaft portion 12 is mounted is a well-known ball lock. The support shaft portion 12 is detachably connected to the support shaft portion 12 through a connecting means 22 having a mechanism.

  Next, in the vulcanization step S2, as shown in FIG. 4, the raw tire T together with the rigid core 1 is put into the vulcanization mold 18, and the rigid core 1 which is the inner mold and the outer mold are formed. Heat vulcanization is performed with the raw tire T sandwiched between the vulcanization mold 18. The vulcanizing mold 18 has a well-known structure, and heating means (not shown) such as a steam jacket and an electric heater for heating the raw tire T to the outside are arranged therein.

  Next, in the cooling step S3, as shown in FIG. 5, the rigid core 1 with the vulcanized tire T1 taken out from the vulcanization mold 18 is cooled. The cooling step S3 includes a tire spray 30 that sprays a fine mist M of water on the outer surface of the vulcanized tire T1, and a core spray 31 that sprays the exposed surface 2S of the core body 2.

  The water fine mist M is water droplets in the form of fine mist, and those having an average particle diameter of 300 μm or less, further 100 μm or less, more preferably 30 μm or less are suitably employed. Such a fine mist M can be easily converted into a mist flow by using, for example, a one-fluid nozzle for mist that ejects water at a high pressure or a two-fluid nozzle for mist that is crushed and ejected with low-pressure air. A commercially available one can be suitably used as the one-fluid nozzle or the two-fluid nozzle for the mist. In order to control the flow rate of the fine mist M, it is preferable to use a two-fluid nozzle. The one-fluid nozzle and the two-fluid nozzle for mist may be collectively referred to as a mist nozzle 33 in some cases.

  In such a fine mist M, water droplets evaporate in the air stream and the temperature of the air stream itself decreases, and the water droplets collide with the vulcanized tire T1 and the core body 2 to evaporate on the surface and take away latent heat. As a result, the cooling effect can be greatly improved as compared with cold air cooling. In particular, since the fine mist M is directly sprayed on the exposed surface 2S of the core body 2, the cooling effect on the core body 2 can be further enhanced. Moreover, since the fine mist M quickly evaporates after colliding with the vulcanized tire T1 and the core body 2, the surface thereof is not substantially wetted. Therefore, even if sprayed directly on the core body 2, the electric heater (heating means 8) for vulcanization heating accommodated inside the core body 2 and the electrical portion that is the wiring portion thereof are not wetted and stable. And safe cooling.

  Further, since the cooling step S3 is distinguished from the tire spray 30 and the core spray 31, the spray amount of the fine mist M and the vulcanized tire T1 and the core body 2 having different thermal conductivity and heat capacity and Spraying time and the like can be controlled separately, and well-balanced cooling such as equalizing the respective cooling rates can be performed.

  In the cooling step S3 of this example, as shown in FIG. 6, as the tire spray 30, a tread that sprays the fine mist M on a plurality of positions Qa in the tire circumferential direction on the outer surface of the tread portion T1a of the vulcanized tire T1. The vulcanized tire T1 is cooled by including the cooling 30a and the sidewall cooling 30b spraying the fine mist M at a plurality of positions Gb in the tire circumferential direction on the outer surfaces of both sidewall portions T1b. Further, as the core spray 31, the fine mist M is sprayed at a plurality of positions Qc in the tire circumferential direction on the exposed surface 2S of the core body 2. Of the outer surface of the core body 2, the range Y between the bead toe end T1e of the vulcanized tire T1 and the outer ends 5e of the side plates 5L and 5U is exposed to the outside. Y is referred to as the exposed surface 2S.

  In the tire spray 30, as shown in FIGS. 6 and 7, the spray pattern of the fine mist M by the mist nozzle 33 is a substantially circular pattern P1, and the core spray 31 is shown in FIGS. Thus, the spray pattern of the fine mist M by the nozzle 33 for mist is made into the flat pattern P2 long in a tire peripheral direction.

  Thus, since the tire spray 30 is divided into the tread cooling 30a and the sidewall cooling 30b, the spray amount and the tread portion T1a and the sidewall portion T1b having different heat capacities due to the rubber thickness and the like Spraying time etc. can be controlled separately and each cooling rate can be made uniform. Moreover, the tire spray 30 can efficiently spray the fine mist M over a wide range by adopting the substantially circular pattern P1.

  On the other hand, in the core spray 31, the exposed surface 2S has a narrow annular band shape. Therefore, by adopting the flat pattern P2, the exposed surface 2S is prevented from protruding from the exposed surface 2S. Can be efficiently sprayed.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  In order to confirm the effect of the present invention, a rigid core with a vulcanized tire (tire size_215 / 45R17) taken out from a vulcanization mold is cooled by the following cooling method, and the core body at that time The temperature change was measured and the result is shown in FIG. As for the temperature of the core body, four temperature sensors (thermocouples) are attached at equal intervals in the circumferential direction at the tire equator position on the core lumen surface, and the average value of the temperature measured by each temperature sensor is used. ing.

As cooling methods, natural cooling (Comparative Example 1), cold air cooling (Comparative Example 2), and mist cooling (Example 1) according to the present invention using fine mist were performed.
(1) In natural cooling (Comparative Example 1), a rigid core with a vulcanized tire was left in a factory at room temperature (25 ° C.) and naturally cooled.
(2) In cold air cooling (Comparative Example 2), a spot cooler was used to forcibly cool a rigid core with a vulcanized tire by blowing cold air at a temperature (15 ° C.) at a wind speed (300 m / min). .
(3) In mist cooling (Example 1), fine mist having an average particle diameter of 10 to 30 μm was sprayed using a two-fluid nozzle. Spray positions are 8 positions on the outer surface of the tread and equally spaced in the tire circumferential direction, 8 positions on the sidewall outer surface and equally spaced in the tire circumferential direction, and on the exposed surface of the core body In addition, eight positions were equally spaced in the tire circumferential direction. The two-fluid nozzle is sprayed from a position 150 mm away from each surface, and the total spray amount of the fine mist is 0.5 liter / min. The tire spray was a circular pattern and the core spray was a flat pattern.

  As shown in FIG. 9, in Example 1, it can be confirmed that the core body can be quickly cooled, and suppression of tire overvulcanization and improvement of tire production efficiency can be achieved.

DESCRIPTION OF SYMBOLS 1 Rigid core 2 Core body 2S Exposed surface 9 Core segment 18 Vulcanization mold 30 Tire spray 30a Tread cooling 30b Side wall cooling 31 Core spray M Fine mist P1 Substantially circular pattern P2 Flat pattern S1 Raw tire formation process S2 Vulcanization process S3 Cooling process T Raw tire T1a Tread part T1b Side wall part

Claims (2)

Raw tire formation for forming a raw tire on the outer surface of the core body using a rigid core having a hollow core that can be disassembled and formed of a plurality of core segments divided in the tire circumferential direction Process,
A vulcanization step in which the raw tire is put together with a rigid core into a vulcanization mold to heat vulcanize the raw tire;
A cooling step of cooling the rigid core with the vulcanized tire taken out from the vulcanization mold,
The cooling step, the water of a fine mist, and a tire spray sprayed onto the outer surface of the vulcanized tire, Ri Do from the core spray for spraying on the exposed surface of the core body,
The tire spray has a substantially circular pattern as the spray pattern of the fine mist,
The core spraying method is characterized in that the spray pattern of the fine mist is a flat pattern that is long in the tire circumferential direction .
The tire spray is a plurality of positions in the tire circumferential direction on the outer surface of the tread portion of the vulcanized tire, the tread cooling that sprays the fine mist, and a plurality of positions in the tire circumferential direction on the outer surfaces of both sidewall portions, Including sidewall cooling to spray fine mist ,
The core spray, a plurality of positions in the tire circumferential direction on the exposed surface of the core body, the tire manufacturing method of claim 1, wherein said benzalkonium be sprayed a fine mist.

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