JPH0919931A - Gas vulcanizing method of elastomeric article and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the quality of an article from lowering and realize the shortening of vulcanizing time by a method wherein a pressurizing medium is fed in a mold after its temperature is raised with a heater so as to realize the temperature uniformization through its mixing with already-filled heating medium in order to vulcanize an elastomeric article without temperature unevenness. SOLUTION: After an elastomeric article installed in a mold is heated by feeding a heating medium 2A, a pressurizing medium 2B is fed in the mold 7 after its temperature is raised with a heater 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for so-called gas vulcanization of elastomer articles, especially rubber tires for vehicles.

[0002]

2. Description of the Related Art Conventionally, for vulcanization of rubber tires for vehicles, a heating medium composed of steam and a high-temperature gas having a high heat capacity, and a pressurizing medium composed of a high-pressure gas having a low heat capacity such as an inert gas or nitrogen gas. A gas vulcanization method that uses both and is widely used.

In general, this is as shown in FIG.
The heating medium having a predetermined temperature and pressure is supplied to the inner space c of the tire b loaded in the mold a from the suction port d provided in the central mechanism in the vulcanizer to heat the tire, When the temperature reaches the reference temperature required for vulcanization or when the reference time has elapsed, the supply of the heating medium is stopped and the pressurizing medium having a higher pressure than the heating medium is filled with the heating medium. By supplying to the internal space c of the tire b,
The internal pressure is rising further. In this method, since any pressure can be selected as the pressurizing medium, the drawback of steam vulcanization, that is, since steam is saturated steam, there is a constant relationship between temperature and pressure. There is an advantage that the drawback that both cannot be satisfied can be compensated.

[0004]

However, in the conventional gas vulcanization method, although the pressurizing medium exhibits a low heat capacity, it is stored at room temperature so that the temperature difference between the pressurizing medium and the heating medium is large. Therefore, when this pressurized medium is supplied to the tire inner space c, mixing and heat exchange with the already filled heating medium are not rapidly achieved, and a low temperature heating is applied in the tire inner space c. The pressure medium tends to separate on the lower side and the hot heating medium tends to separate on the upper side. As a result, the temperature rise of the tire to be vulcanized is different between the upper side b1 and the lower side b2, and the degree of vulcanization is partially reduced,
There is a problem that the quality is deteriorated and the vulcanization time is increased.

The present invention is based on the fact that the pressure medium is heated in advance by a heater prior to the supply of the pressure medium to a mold, and gas vulcanization of an elastomer article which can solve the above problems. It is intended to provide a method and an apparatus thereof.

[0006]

In order to achieve the above object, the first invention of the present application is to provide a heating medium composed of a gas having a high heat capacity and a high temperature to heat an elastomer article to be loaded into a mold. The method for gas vulcanization of an elastomer article is characterized in that a pressurized medium composed of a gas having a low heat capacity and a high pressure is heated by a heater and supplied into the mold.

The second invention of the present application is to supply a heating medium consisting of a gas having a high heat capacity and a high temperature and to communicate with the inside of the mold through a heating on-off valve and a gas having a low heat capacity and a high pressure. A pressurizing medium that supplies the pressurizing medium and communicates with the inside of the mold through the pressurizing on-off valve, and the pressurizing medium is interposed between the pressurizing supply source and the pressurizing on-off valve. A gas vulcanizing apparatus for an elastomer article, comprising: a heater for raising a temperature.

As the heater, a heat source is provided around the supply pipe through which the pressurizing medium passes, by externally inserting the supply pipe with a gap and providing an outer cylinder for passing the heating medium in the gap. An exchanger can be used, and a heater in which an electric heating coil is mounted around the supply pipe can also be used.

As described above, according to the present invention, since the high-pressure pressurized medium is heated by the heater and then supplied into the mold, the mixing with the heating medium already filled in the mold is performed. Are homogenized in temperature, the elastomer article can be vulcanized at a predetermined temperature without temperature unevenness, quality deterioration can be prevented, and vulcanization time can be shortened.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A gas vulcanizing method of the first invention will be described below with reference to the drawings together with an embodiment of a gas vulcanizing apparatus of the second invention.

FIG. 1 is a structural explanatory view showing an embodiment of a gas vulcanizing apparatus 1 of the second invention. The gas vulcanizing apparatus 1 is
In this example, it is an unvulcanized elastomer article, and is composed of a device body 1A for loading a vehicle tire T, and a piping system 1B for supplying the vulcanization medium 2 to the device body 1A.

Here, the vulcanizing medium 2 is a heating medium 2 made of a high-temperature gas having a high heat capacity, which is steam in the form of saturated vapor.
A is a general term for the pressurizing medium 2B composed of a high-pressure gas having a low heat capacity, such as an inert gas, usually nitrogen gas, and these are referred to as a heating medium 2A and a pressurizing medium 2B.

The apparatus main body 1A comprises a mold 7 composed of, for example, an upper mold 5 and a lower mold 6 which are vertically separable around a central mechanism 3 concentric with the tire shaft. By contacting the split surface of the mold 6, the vulcanization chamber 9 for tire loading, which has the contour of the finished tire T, is formed.

Further, the central mechanism 3 has a suction port 10 for sucking and discharging the vulcanizing medium 2 into the vulcanization chamber 9, and a discharge port 1.
1 is opened respectively, and in the present example, this vulcanization medium 2
A rubber bag-shaped bladder 12 for preventing direct contact between the tire T and the tire T is attached. The vulcanization chamber 9 may be directly filled with the vulcanization medium 2 without heating the bladder 12, and the vulcanization medium 2 may be heated and pressurized.

The piping system 1B comprises an inlet pipe 13 for supplying the vulcanizing medium 2 to the vulcanizing chamber 9 and an outlet pipe 14 for taking out the vulcanizing medium 2 from the vulcanizing chamber 9.

In this example, the inlet pipe 13 is for heating a heating supply source 17 for generating and supplying the heating medium 2A to a branch point 15P at the other end of the conduit 15 whose one end is connected to the inlet 10. Heating pipe 19 connected via an on-off valve 16
A, and a pressurizing pipe 19B connecting a pressurizing supply source 21 for generating and supplying the pressurizing medium 2B to the branch point 15P via a pressurizing on-off valve 20. The on-off valves 16 and 20
The valve operation selectively supplies only one of the heating medium 2A and the pressurizing medium 2B into the vulcanization chamber 9, and the supply of the heating medium 2A or the pressurizing medium 2B is performed at the time of taking out a tire, shaping or the like. You can stop.

Further, in the inlet side pipe 13, the pressurizing medium 2B is interposed between the pressurizing supply source 21 and the pressurizing on-off valve 20.
A heater 22 for raising the temperature is arranged.

In the present embodiment, the heater 22 is, as shown in FIG. 2, provided around the supply pipe 23 through which the pressurizing medium 2B passes, with the supply pipe 23 having an interval D, and the gap. A heat exchanger having an outer cylinder 25 for passing the heating medium 2A in D, wherein the supply pipe 2 is provided by heat exchange with the heating medium 2A.
The pressurized medium 2B is heated via 3. The heater 2
As shown in FIG. 3, the heating element 2 has a partition wall 26 extending spirally in the longitudinal direction in a closed gap D having an inlet IP and an outlet OP of the heating medium 2A.
The passage length of A is increased to improve the heat exchange efficiency.

Further, in order to supply the heating medium 2A to the heater 22, as shown in FIG. 1, the inlet pipe 13 is provided between the heating source 17 and the heating on-off valve 16. Inlet IP of the heating pipe 19A and the heater 22
A heating pipe 29 is provided to connect the and via the on-off valve 27, and the heating medium 2A from the heating device 22 is exhausted or returned to the heating supply source 17 at the outlet OP of the heating device 22. The exhaust pipe 31 is connected with the opening / closing valve 30. In this example, an open / close valve 28 for turning on / off the supply of the pressurized medium is also provided between the heater 22 and the pressurized supply source 21.

In this embodiment, the outlet pipe 14 has a conduit 32 whose one end is connected to the discharge port 11, and the conduit 32.
An exhaust pipe 35 connected to the branch point 32P at the other end via an open / close valve 33, and a pressure reducing pipe 38 connected to the vacuum 37 via an open / close valve 36 are provided at the branch point 32P.
The vacuum 37 is used to fold the bladder 12 by applying a negative pressure in the vulcanization chamber 9 when the tire is taken out of the mold 7 after the vulcanization treatment. Therefore, when the bladder 12 is not provided, On-off valve 36, vacuum 37
Also, the decompression pipe 38 may be omitted.

Further, the conduits 1 and 3 are provided in the piping system 1B.
2, three-way valves 40 and 41, which are three-way valves, are interposed, and a free-form port 40a of one of the three-way valves 40 is connected to, for example, a supply source 42 of a shaping medium for tire molding and the other three-way valve. 41 free ports 41a
An exhaust pipe of a shaping medium is connected to the.

However, the open / close valves 27 and 3 are provided during or after the completion of tire molding (shaping) in the mold 7.
1 is opened, the heating medium 2A is introduced into the heater 22, and the supply pipe 23 is preheated and heated. At this time, the other on-off valves 16 and 2
0, 28, 33, 36 are closed, and the shaping medium is supplied to / exhausted from the vulcanization chamber 9 via the three-way valves 40, 41.

After the shaping, the on-off valve 16 is opened and the heating medium 2A from the heating supply source 17 is supplied to the heating pipe 1.
9A and the conduit 15 are introduced into the vulcanization chamber 9, and the tire heating process is performed. At this time, the heating medium 2A is usually used in the range of 14 to 15 kg / cm ² and 198 to 200 ° C., and the heating step takes about 2.5 minutes.

After this heating step, the on-off valve 16 is closed and opened.
The closing valves 20 and 28 are sequentially opened, and the heating medium 2A
Supply is cut off, for example, pressure is 18-30kg
/cm ^TwoThe pressurized medium 2B of a certain degree
Introduced into the vulcanization chamber 9 through the pipe 19B and the conduit 15,
The pressurizing step is performed for about 12.5 minutes at the high temperature. Before
The pressure medium 2B is heated when being introduced into the vulcanization chamber 9.
By passing through the supply pipe 23, for example, about 40 ℃
The temperature is raised from room temperature to about 160 ℃ during the heating process.
Temperature unevenness when mixing with already supplied heating medium 2A
Is reduced. This temperature unevenness is caused by the heated pressurizing medium 2.
As the temperature of B approaches the temperature of the heating medium 2A, it is reduced.
You.

After the vulcanization process consisting of the heating and pressurizing steps is completed, the on-off valves 20 and 28 are closed, and the pressurizing medium 2B.
Is stopped, the on-off valve 33 is opened, and the heating medium 2A and the pressurizing medium 2B in the vulcanization chamber 9 are exhausted to the atmosphere, for example, through the conduit 32 and the exhaust pipe 35.

When the tire T is taken out of the mold 7, the open / close valve 33 is closed and the open / close valve 36 is opened to open the vulcanization chamber 9.
The negative pressure is applied, and the bladder 12 is folded.

FIG. 4 discloses another embodiment of the heater 22. In the figure, the heater 22 is a heater, and in the present example, an electric heating coil 43 that heats the supply pipe 23 by energization is mounted around the supply pipe 23.

[0028]

[Examples] Based on the specifications of Table 1, the vulcanization method of FIG. 1 was used to vulcanize a raw tire for tire size 185R14,
At that time, the difference in vulcanization temperature increase between the bead portion B1 on the upper side of the tire and the bead portion B2 on the lower side of the tire was comparatively measured. Similarly, the difference in increase in vulcanization temperature during vulcanization using the conventional method was comparatively measured, and the measurement results are shown in FIG.

As shown in FIG. 5, in the vulcanization method of the embodiment, the difference in vulcanization temperature between the upper bead portion B1 and the lower bead portion B2 after entering the pressurizing step is reduced, and the quality is deteriorated. You can see that is suppressed. Moreover, the time required for vulcanization is
The vulcanization is delayed, that is, the vulcanization degree is determined on the side of the bead portion B2 where the vulcanization degree is low. be able to.

[0030]

[Table 1]

[0031]

As described above, in the method and apparatus for gas vulcanizing an elastomer article according to the present invention, during the pressurizing step, the pressurizing medium is heated by a heater and supplied into the mold. For,
The mixing with the already filled heating medium is temperature-uniformized, the elastomer article can be vulcanized without temperature unevenness, the quality deterioration can be prevented, and the vulcanization time can be shortened.

[Brief description of the drawings]

FIG. 1 is a structural explanatory view showing an embodiment of a vulcanizing apparatus of the present invention.

FIG. 2 is a perspective view showing an example of a heater that can be used in the present invention.

FIG. 3 is a schematic sectional view thereof.

FIG. 4 is a perspective view showing another example of a heater.

FIG. 5 is a graph showing a vulcanized state of a tire by the vulcanizing apparatus of the present invention.

FIG. 6 is a configuration explanatory view illustrating a conventional gas vulcanizing apparatus.

[Explanation of symbols]

 2A heating medium 2B pressurizing medium 7 mold 16 heating on-off valve 17 heating supply source 20 pressurizing on-off valve 21 pressurizing supply source 22 heater 23 supply pipe 25 outer cylinder 43 electric heating coil D gap

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[Procedure amendment]

[Submission date] August 16, 1995

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

[Figure 5]

Claims (4)

[Claims] 1. A heating medium comprising a gas having a high heat capacity and a high temperature is supplied to heat an elastomer article to be loaded into a mold, and then a pressure medium comprising a gas having a low heat capacity and a high pressure is heated by a heater. The method for gas vulcanization of an elastomer article is characterized in that the gas is supplied into the mold. 2. A heating medium consisting of a gas having a high heat capacity and a high temperature and a heating supply source communicating with the inside of the mold through a heating on-off valve, and a pressurized medium consisting of a gas having a low heat capacity and a high pressure. A pressurizing supply source communicating with the inside of the mold via the pressurizing on-off valve, and a heater for interposing between the pressurizing supply source and the pressurizing on-off valve to raise the temperature of the pressurizing medium. Vulcanizing apparatus for elastomeric articles comprising. 3. The heater has an outer cylinder around a supply pipe through which the pressurizing medium passes, the supply pipe being externally inserted with a gap, and the heating medium passing through the gap. The gas vulcanization device for an elastomer article according to claim 2, which is a heat exchanger that heats the supply pipe by heat exchange with a heating medium. 4. The heater has an electric heating coil mounted around a supply pipe through which the pressurizing medium passes, and is a heater for heating the supply pipe by energizing the electric heating coil. The gas vulcanization device for elastomer articles according to claim 2.