JP2005349789A - Internal pressure holding method at time of feed process of pneumatic radial tire and internal pressure holding apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal pressure holding method for keeping the shape of a green tire easy to deform constant by applying internal pressure to a vulcanizing bladder unit for both of molding and vulcanization during a feed process and the green tire by an internal pressure holding device to always keep internal pressure constant to prevent the lowering of quality, and an internal pressure holding apparatus therefor. <P>SOLUTION: The internal pressure holding apparatus 30 is installed on feed trucks 18 and 20 for feeding a primary green tire Wa and a secondary green tire Wb, both of which have vulcanizing bladder units 16 mounted thereon, as shown by Fig. to keep the internal pressures of the primary and secondary green tires Wa and Wb constant. This internal pressure holding apparatus 30 is constituted of the high pressure tank 31 and pressure adjusting valve 32 installed on the feed trucks 18 and 20 connected to the vulcanizing bladder unit 16 by a rotary seal 33. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an internal pressure maintaining method and an internal pressure maintaining apparatus thereof during a pneumatic radial tire transport process, and more specifically, after shaping a primary green tire equipped with a vulcanization bladder unit for both molding and vulcanization, The present invention relates to an internal pressure holding method and an internal pressure holding device for a pneumatic radial tire in a conveying process in which the internal pressure of a vulcanization bladder unit is kept constant in each conveying process up to the two-stage molding process and immediately before the vulcanizing process.

  In recent years, large tires for construction vehicles, called OR tires (Off the Road Tire), have been increasing in production of radial tires due to the increase in size and speed of vehicles.

  In such a radial tire manufacturing method, a primary green tire (unvulcanized tire) forming a tire skeleton such as a carcass ply or a bead core is first molded by a first stage molding machine, and then the primary green tire is second stage. Inflate until the specified outer diameter is achieved by the bladder mechanism of the molding machine, form a belt and tread rubber around the outer periphery, and form it into a finished green tire, and then inflate the finished green tire with a vulcanization bladder. Then, it is molded to be vulcanized with a vulcanizer.

  Conventionally, as an improvement of a method for manufacturing a pneumatic radial tire, a technical idea has been proposed in which an inflation bladder for a second-stage molding machine and an inflation bladder for a vulcanizer are combined (for example, patents). Reference 1).

  However, after inserting the primary green tire into the conventional molding and vulcanizing bladder unit, during the conveying process from shaping to the main spindle of the second stage molding machine by shaping with a constant pressure for the purpose of maintaining the shape, From the seal ring of the bladder unit for both molding and vulcanization during the transportation process until the secondary green tire with the belt reinforcement layer or cap tread attached to the primary green tire is inserted into the mold for vulcanization molding. The internal pressure leaked, and the shapes of the primary green tire and the secondary green tire could not be maintained.

In particular, in the case of a mechanism having a relatively low holding pressure of 0.03 to 0.1 mPa in the bladder unit and the green tire, high processing accuracy is required to obtain a complete seal mechanism. There is a problem that the cost is increased due to processing and mechanism, and it is conceivable that the internal pressure is maintained by the seal ring itself, but it may be difficult to completely seal due to the mechanism of the apparatus.
Japanese Patent Laid-Open No. 49-15776

  This invention pays attention to such conventional problems, and applies an internal pressure to the molding / vulcanizing vulcanization bladder unit and the green tire during the conveying process by an internal pressure holding device so as to keep the internal pressure constant. An object of the present invention is to provide an internal pressure holding method and an internal pressure holding device for a pneumatic radial tire that can be maintained in a shape that is easily deformed to prevent deterioration of the quality of the green tire during the conveying process. It is.

  In order to achieve the above-mentioned object, the present invention provides an internal pressure maintaining method during a pneumatic radial tire transporting process in which an inner diameter portion of a primary green tire molded by a first stage molding machine is used for both molding and vulcanization. After the vulcanization bladder unit is mounted and the primary green tire is shaped, the vulcanization bladder unit and the green tire are maintained for the purpose of maintaining the shape of the green tire in each of the second-stage molding process and immediately before the vulcanization process. An internal pressure maintaining method in a pneumatic radial tire transporting process for maintaining a constant internal pressure, wherein the internal pressure retaining device is installed in a transport cart for transporting a primary green tire and a secondary green tire to which the vulcanized bladder unit is mounted. Thus, the gist is to keep the internal pressure of the primary green tire and the secondary green tire constant. That.

  Further, the internal pressure holding device during the pneumatic radial tire transport process of the present invention is equipped with a vulcanization bladder unit for both molding and vulcanization on the inner diameter portion of the primary green tire molded by the first stage molding machine, After shaping the primary green tire, the internal pressure during the transportation process of the pneumatic radial tire that keeps the internal pressure of the vulcanization bladder unit and the green tire constant in each transportation process until the second stage molding process and immediately before the vulcanization process. An internal pressure holding device for holding the internal pressure of the primary green tire and the secondary green tire constant on a transport carriage for transporting the primary green tire and the secondary green tire equipped with the vulcanization bladder unit. The gist of this is that

  Here, the said internal pressure holding | maintenance apparatus is comprised with the high pressure tank and pressure control valve which were installed on the said conveyance trolley, and this internal pressure holding | maintenance apparatus is connected to the said vulcanization bladder unit by a rotary seal. The pressurized gas in the high pressure tank is preferably nitrogen gas.

Since the present invention is configured as described above, the following excellent effects can be obtained. (A). By applying an internal pressure to the molding / vulcanizing vulcanization bladder unit and green tire during the conveyance process using an internal pressure holding device, the internal pressure is always kept constant, so that the shape of the easily deformable green tire is kept constant. It is possible to prevent the quality from deteriorating.
(B). Since the shape of the easily deformable green tire can be kept constant, various manufacturing failures accompanying the deformation of the green tire, such as poor carcass cord alignment (code wave failure), poor rubber flow at the side (light side failure) ) Can be suppressed.
(C). Since the vulcanization bladder unit for both molding and vulcanization is held at a constant internal pressure, the shape of the green tire can be kept constant in the flow of each molding process. (500-4,500 kg: 700-750 kg for the primary green tire in the case of 2700R49 size, 1,400 kg-1,500 kg for the finished green tire), a special device for maintaining the shape of the green tire is required However, this is not necessary in the internal pressure maintaining method of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
1 (a) to 1 (l) show schematic configuration diagrams of, for example, a manufacturing process of a pneumatic radial tire for a construction vehicle in which the present invention is implemented. In this manufacturing process, FIG. The process of manufacturing the primary green tire Wa in the molding drum 12 of the molding machine 11, FIG. 1 (b) does not attach a belt tread or the like to the primary green tire Wa removed from the molding drum 12 of the first stage molding machine 11. FIG. 1 (c) shows a cylindrical bladder 15 clamped by an upper mold clamp ring 13 and a lower mold clamp ring 14 at the inner diameter of the primary green tire Wa. wearing the vulcanized bladder unit 16 having, by vulcanization bladder unit 16 to the bead spacing of the primary green tire Wa to B _1, introducing a pressurized fluid such as compressed air to the bladders 15 A primary green tire Wa inflate Te, to the outer diameter of the primary green tire Wa to D.

FIG. 1D shows that the primary green tire Wa is made to have a bead interval B ₂ by the vulcanization bladder unit 16 and a pressurized fluid such as compressed air is introduced into the bladder 15 to inflate the primary green tire Wa. At this time, the primary green tire Wa held at a predetermined bead interval B ₂ is held by a conveying carriage 18 such as a carriage, which is held at an outer diameter D ₂ necessary for attaching a belt tread or the like in the second stage molding machine 17. This is a step of conveying the primary green tire Wa to the position of the reversing device 19.

  FIG. 1 (e) shows a process of horizontally transferring the primary green tire Wa to the reversing device 19, and FIG. 1 (f) shows the turning operation of the primary green tire Wa in the horizontal state by 90 ° in the vertical state. Process, Fig. 1 (g) shows the primary green tire Wa in a vertical state is attached to the molding spindle 17a of the second stage molding machine 17 together with the vulcanization bladder unit 16, and the belt tread T is wound around the primary green tire Wa. FIG. 1 (h) shows a step of attaching the formed secondary green tire Wb to the reversing device 19 again in the vertical direction. FIG. 1 (i) shows a step of forming the secondary green tire Wb. The step of turning 90 ° horizontally by the reversing device 19, FIG. 1 (j) is the step of transferring the secondary green tire Wb from the reversing device 19 to the transport carriage 20 such as a carriage.

Figure 1 (k) is a secondary green tire Wb and the bead spacing B ₃ by vulcanization bladder unit 16, pressure such as compressed secondary green tire Wb so that the outer diameter D ₂ of the vulcanization air the step of inflating by introducing a fluid, FIG. 1 (l) of the vulcanization mold vulcanizer while wearing the vulcanized bladder unit 16 a secondary green tire Wb molded to the outer diameter D ₂ of the vulcanization No. 21, and the secondary green tire Wb is heated and pressurized in the vulcanization mold 21 while maintaining the inflated state, and is cured to complete a pneumatic radial tire.

  In this invention, the vulcanization bladder unit 16 for both molding and vulcanization is mounted on the inner diameter portion of the primary green tire Wa formed by the first stage molding machine 11 of FIGS. 1 (b) to (g). After shaping the primary green tire Wa, the transporting process to the second stage molding machine 17 and the secondary green tire Wb molded by the second stage molding machine 17 shown in FIGS. It is the internal pressure holding | maintenance apparatus 30 implemented in each conveyance process until just before the process put into the vulcanization mold 21 of a vulcanizer.

  As shown in FIG. 2, the internal pressure holding device 30 is installed on the transport carriages 18 and 20 for transporting the primary green tire Wa and the secondary green tire Wb to which the vulcanization bladder unit 16 is attached, and the primary green tire The internal pressure of the Wa and the secondary green tire Wb is kept constant, and the internal pressure holding device 30 includes a high-pressure tank 31 and a pressure regulating valve 32 installed on the transport carriage 18, and this internal pressure holding device. 30 is connected to the vulcanization bladder unit 16 by a rotary seal 33 as shown in FIG.

  The rotary seal 33 is composed of a rotatable housing 34 fixed to the main shaft 17 a and a ring member 35 accommodated in the housing 34, and a communication hole 36 formed in the housing 34 and the ring member 35. A pressurized gas supply pipe 37 for holding the internal pressure is connected, and the pressurized gas from the high pressure tank 31 is supplied to the vulcanization bladder unit 16 through the pressure regulating valve 32 and the rotary seal 33. As the pressurized gas in the high-pressure tank 31, it is preferable to use nitrogen gas from the viewpoint of durability against bladder deterioration (reversion) during vulcanization.

  In the present invention, the vulcanization bladder unit 16 for both molding and vulcanization is mounted on the inner diameter portion of the primary green tire Wa molded by the first stage molding machine 11, and after shaping the primary green tire Wa, The internal pressure of the vulcanization bladder unit 16 and the green tires Wa, Wb is held constant by the internal pressure holding device 30 for the purpose of maintaining the shape of the green tires Wa, Wb in each conveying step until the two-stage molding step 17 and immediately before the vulcanization step. Is the method.

  That is, the internal pressure holding device 30 including the high pressure tank 31 and the pressure regulating valve 32 installed on the transport carriages 18 and 20 that transport the primary green tire Wa and the secondary green tire Wb to which the vulcanization bladder unit 16 is mounted. By supplying nitrogen gas of a predetermined pressure to the primary green tire Wa and the secondary green tire Wb, the internal pressure is kept constant, thereby keeping the shapes of the easily deformable green tires Wa and Wb constant. Therefore, by maintaining the shape of the green tires Wa and Wb that are easy to be deformed and maintaining a constant shape, various manufacturing failures associated with the deformation of the green tires Wa and Wb, such as misalignment of carcass cords (code wave Failure), the occurrence of poor rubber flow at the side (light side failure) can be suppressed.

1 (a) to 1 (l) are schematic configuration diagrams of a manufacturing process of a pneumatic radial tire embodying the present invention. It is explanatory drawing of the internal pressure holding | maintenance apparatus installed on the conveyance trolley which implemented this invention. It is explanatory drawing of the rotary seal used with an internal pressure holding | maintenance apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 1st stage molding machine 12 Forming drum 13 Upper mold | type clamp ring 14 Lower mold | type clamp ring 15 Bladder 16 Vulcanization bladder unit 17 2nd stage molding machine 17a Molding main axis | shaft 18 Conveyance carriage 19 Reverse device 20 Conveyance carriage 21 Vulcanization mold 30 Internal pressure holding device 31 a high-pressure tank 32 pressure regulating valve 33 rotary seal 34 spindle 35 ring member 36 communicating holes 37 feed pipe Wa 1 primary green tire Wb 2 primary green tire B _1, B _2, B ₃ bead spacing D, D _1, D ₂ Outer diameter

Claims (4)

A vulcanization bladder unit for both molding and vulcanization is mounted on the inner diameter of the primary green tire molded by the first stage molding machine, and after shaping the primary green tire, the second stage molding process and vulcanization process An internal pressure holding method during a pneumatic radial tire conveyance process that maintains the internal pressure of the vulcanization bladder unit and the green tire constant for the purpose of maintaining the shape of the green tire in each conveyance process until immediately before,
The internal pressure of the primary green tire and the secondary green tire is kept constant by an internal pressure holding device installed on a transport carriage that transports the primary green tire and the secondary green tire equipped with the vulcanized bladder unit. An internal pressure maintaining method during the conveying process of the pneumatic radial tire. A vulcanization bladder unit for both molding and vulcanization is mounted on the inner diameter of the primary green tire molded by the first stage molding machine, and after shaping the primary green tire, the second stage molding process and vulcanization process An internal pressure holding device in a pneumatic radial tire conveyance process that maintains a constant internal pressure of the vulcanization bladder unit and the green tire in each conveyance process until immediately before,
An internal pressure holding device for maintaining a constant internal pressure of the primary green tire and the secondary green tire is installed on a transport carriage that transports the primary green tire and the secondary green tire equipped with the vulcanized bladder unit. An internal pressure holding device in the pneumatic radial tire transport process. 2. The pneumatic radial according to claim 1, wherein the internal pressure holding device includes a high-pressure tank and a pressure regulating valve installed on the conveyance carriage, and the internal pressure holding device is connected to the vulcanization bladder unit by a rotary seal. Internal pressure holding device during the tire transport process. The pressurized gas in the high-pressure tank is nitrogen gas, The internal pressure holding device in the pneumatic radial tire conveying process according to claim 2 or 3.

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