JP2002052536A - Tire vulcanizing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire vulcanizing method capable of accurately imparting quantity of heat necessary for vulcanization to a mold in a multimold system using electromagnetic induction heating. SOLUTION: In a method for vulcanizing a tire by charging an unvulcanized tire T in the mold disposed in the container 1 at an on-off station 10 and heating the mold at a heating station 20 by an electromagnetic induction coil 21 and subsequently feeding the container 1 to a vulcanizing station 30, the temperature of the unvulcanized tire T charged in the mold is measured to calculate temperature difference with respect to predetermined reference temperature and, on the basis of this temperature difference, the quantity of heat supplied to the mold is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for vulcanizing a tire, in which a container of a mold heated by electromagnetic induction is continuously transferred to a vulcanizing station. The present invention relates to a tire vulcanizing method which is applied to a tire with high accuracy.

[0002]

2. Description of the Related Art As a general tire vulcanizer, there is a tire vulcanizer in which a mold is heated by a heating device for introducing steam therein, and an unvulcanized tire inserted into the mold is vulcanized.
In such a tire vulcanizer, the temperature is detected at the outlet pipe of the steam discharged from the heating device, and the supply temperature of the steam is adjusted based on the measured temperature so that the mold temperature is kept constant. ing.

[0003] However, the above-mentioned tire vulcanizer needs to be provided with a boiler for generating steam and a pipe for guiding the steam to the boiler. Therefore, there is a problem that the tire manufacturing equipment becomes complicated and the equipment cost increases.

On the other hand, in recent years, an electromagnetic induction vulcanizer using an electromagnetic induction coil has been proposed. In this electromagnetic induction vulcanizer, in a state where an unvulcanized tire is inserted into a mold having a large heat capacity, heat is supplied from the electromagnetic induction coil to the mold in a short time, and heat is stored. Tires are gradually vulcanized by thermal energy. Such an electromagnetic induction vulcanizer does not require a boiler or piping, and can use a heating facility including an electromagnetic induction coil in common for a plurality of molds, thereby simplifying tire manufacturing equipment and reducing equipment costs. Can be reduced.

[0005] However, in the above-described electromagnetic induction vulcanizer, the heating time is short, but even if the mold having a large heat capacity is heated from the outside, the rise in temperature inside is greatly delayed. There is a problem that heating control cannot be performed based on the above. For this reason, when the initial temperature of the unvulcanized tire supplied from the molding step is different for each vulcanization, the calorie required for vulcanization cannot be given with high accuracy. In particular, in a multi-mold system in which a tire is vulcanized while continuously moving a plurality of containers, it is difficult to change a preset vulcanization time due to the relationship between a mold opening / closing step and a heating step. Therefore, it is extremely important to accurately give the amount of heat required for vulcanization.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for vulcanizing a tire, which is capable of accurately supplying the amount of heat required for vulcanization to a mold in a multi-mold system using electromagnetic induction heating. To provide.

[0007]

According to the tire vulcanizing method of the present invention for achieving the above object, an unvulcanized tire is put into a mold installed in a container, and the mold is heated by electromagnetic induction. Thereafter, in the method of transporting the container to a vulcanizing station and performing tire vulcanization, the temperature of an unvulcanized tire to be charged into the mold is measured, a temperature difference with respect to a predetermined reference temperature is determined, and the temperature difference is determined. The amount of heat supplied to the mold is controlled based on the amount of heat.

More specifically, when the temperature of the unvulcanized tire is at a predetermined reference temperature, a reference heat amount required for vulcanization is previously determined, and the temperature of the unvulcanized tire to be charged into the mold is determined. Is measured, a correction value for the reference calorific value is calculated based on the temperature difference between the tire temperature and the reference temperature,
The correction value is added to the reference heat amount.

As described above, the temperature of the unvulcanized tire to be charged into the mold is measured, the temperature difference with respect to a predetermined reference temperature is obtained, and the amount of heat supplied to the mold is controlled based on the temperature difference, thereby obtaining the uncured tire. Even if the initial temperature of the vulcanized tire varies from vulcanization to vulcanization, the amount of heat required for vulcanization can be accurately given. Therefore, using electromagnetic induction heating,
In a multi-mold system for performing tire vulcanization while continuously moving a plurality of containers, it is possible to reduce variations in tire quality without changing a preset vulcanization time.

In the present invention, the reference temperature of the unvulcanized tire can be set arbitrarily near the average temperature of the unvulcanized tire supplied from the molding step. However, the reference temperature must be set for each temperature measurement position of the unvulcanized tire. The temperature measurement of the unvulcanized tire may be performed at least at one of the bead portion and the tread portion where the rubber volume is large and vulcanization is the slowest.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a schematic plan view showing a multi-mold system according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a container thereof.

As shown in FIG. 1, the multi-mold system includes an opening / closing station 10 for opening and closing a mold.
A heating station 20 for heating the mold; and a vulcanization station 30 for holding a plurality of heated containers 1 on standby.
0 are connected to each other via a container transport device 40. The opening and closing station 10 and the vulcanization station 3
At a position between 0 and the position facing the heating station 20, a heat retaining cover detaching device 50 is provided.

As shown in FIG. 2, the mold accommodated in the container 1 is a lower mold 2a for molding a side portion of the tire T.
And an upper die 2b and a plurality of sectors 2c for forming a tread portion. The lower die 2a is mounted on a bottom plate 3a, and the upper die 2b is mounted on a top plate 3b that can move forward and backward with respect to the bottom plate 3a.
Is mounted on a segment 3c slidable in the tire radial direction on the bottom plate 3a. Therefore, the mold can be opened and closed by moving the top plate 3b up and down with respect to the bottom plate 3a with all the segments 3c expanded in the tire radial direction. An outer ring 4 is fitted on the outer peripheral side of the segment 3c, whereby a self-locking state is established to maintain the internal pressure during vulcanization. Further, after the mold is heated, the outside of the container 1 is covered with a heat retaining cover 5 as necessary.

On the other hand, a bladder 6 made of an elastic material such as rubber is provided inside the tire T. This bladder 6
Is a pair of upper and lower clamps 8 of the bladder operation mechanism 7.
a, 8b. These clamps 8a,
8b, the mutual interval changes due to the sliding expansion and contraction of the center shaft 9, whereby the bladder 6 contracts or expands. The bladder operation mechanism 7 includes a heating medium supply path (not shown) for supplying a heating medium such as heating steam into the bladder 6.

In FIG. 1, the opening / closing station 10 comprises:
The mold installed inside the container 1 is opened and closed. In the vicinity of the opening and closing station 10, an uncured tire T
And a tire unloader 12 for taking out the vulcanized tire T from the mold. The loaders 11 and 12 are installed so as to be rotatable around rotating shafts 11a and 12a, respectively. Further, the opening / closing station 10 is provided with a heating medium supply unit (not shown) connected to the heating medium supply path of the container 1. The container 1 is transported from the opening / closing station 10 to the heating station 20 via the rail 13.

As shown in FIG. 2, the heating station 20 brings a plurality of electromagnetic induction coils 21 closer to the container 1 from the upper side, the lower side, and the outer peripheral side, and energizes the electromagnetic induction coils 21 in this state, thereby passing through the container 1. To heat the mold.

The vulcanizing station 30 is a place where the containers 1 heated by the heating station 20 are sequentially received and waited until vulcanization is substantially completed. The vulcanized containers 1 are sequentially sent out to the opening and closing station 10.

The container transport device 40 is located at the station 1
Rail 41 extending linearly along 0, 20, 30
And transfer means (not shown) for delivering the container 1 to each station. The container 1 is opened and closed via the container transport device 40,
It is conveyed in the order of the heating station 20 and the vulcanization station 30, and returns to the opening / closing station 10 again.

The heat retaining cover detaching device 50 is a device for attaching the heat retaining cover 5 to the container 1 heated at the heating station 20 and removing the heat retaining cover 5 from the container 1 which has been almost completely vulcanized at the vulcanization station 30. It is.

Next, a tire vulcanizing method using the above-mentioned multi-mold system will be described. First, in the opening / closing station 10, the mold of the container 1 is opened, and the unvulcanized tire T is loaded into the mold by the tire loader 11. However, when the vulcanized tire T is present in the mold, the unvulcanized tire T is loaded after the vulcanized tire T is removed from the mold by the tire unloader 12. After closing the mold, a heating medium is supplied into the bladder 6 of the container 1 to shape the unvulcanized tire T. The container 1 is transported to the heating station 20 while maintaining the shaping state of the tire T.

Next, at the heating station 20,
The mold is heated by the electromagnetic induction coil 21 via the container 1 in a short time. The amount of heat given by this electromagnetic induction is accumulated inside the container 1, and the thermal energy causes the vulcanization of the tire T to gradually progress. The container 1 is conveyed to the vulcanizing station 30 via the tire conveying device 40, and the heat insulating cover attaching / detaching device 50 attaches the heat insulating cover 5 to the container 1 on the way.

Next, at the vulcanizing station 30,
The heated container 1 is placed at a predetermined position, and waits until tire vulcanization is substantially completed. The container 1 in which the tire vulcanization is substantially completed is sequentially sent out to the opening / closing station 10, and the heat retaining cover attaching / detaching device 50 removes the heat retaining cover 5 from the container 1 on the way.

By repeating the above-described vulcanization cycle, tire vulcanization can be performed while continuously moving the plurality of containers 1. In this way, the multi-mold system using electromagnetic induction heating does not require a boiler or piping, and the heating equipment including the electromagnetic induction coil can be used in common for a plurality of molds. Simplification and reduction of equipment cost are possible.

In the above multi-mold system, it is difficult to change the preset vulcanization time due to the relationship between the mold opening / closing step and the heating step. It is required to give well. However, for example, when the unvulcanized rubber is extruded into a strip shape by a strip winding method and at least a part of the unvulcanized tire is molded, the initial temperature of the unvulcanized tire supplied from the molding step is variously different. There is. If the initial temperature of the unvulcanized tire is different for each vulcanization, it is difficult to accurately give the calorific value required for vulcanization.

Therefore, in the present invention, the initial temperature of the unvulcanized tire T to be put into the mold is measured, a temperature difference with respect to a predetermined reference temperature is determined, and based on the temperature difference, the heating station 20 sets the temperature of the container 1 in the mold. The amount of heat to be supplied is increased or decreased.

To measure the temperature of the unvulcanized tire T, for example, a non-contact type thermometer such as an infrared thermometer 14 or a contact type thermometer such as an infrared thermometer 14 is disposed in the vicinity of the tire loader 11, and the tire immediately before loading is placed by the thermometer. What is necessary is just to measure temperature. This temperature measurement is performed at least at one of the bead portion and the tread portion of the tire T. Since the bead and tread have a large rubber volume and the slowest vulcanization,
The temperature of this part greatly affects the amount of heat required for vulcanization.

The amount of heat supplied to the mold can be controlled as follows. First, for an unvulcanized tire T having a specific specification, a reference heat amount required for vulcanization when the initial temperature is a predetermined reference temperature is obtained in advance.
Then, the temperature of the unvulcanized tire T is measured just before being put into the mold, and the temperature difference between the tire temperature and the reference temperature is determined. If the tire temperature matches the reference temperature, the reference heat amount may be given.

On the other hand, when there is a temperature difference between the tire temperature and the reference temperature, a correction value for the reference heat amount is calculated based on the temperature difference, and a total heat amount obtained by adding the correction value to the reference heat amount is provided. To The correction value can be obtained from the relationship between the temperature difference and the tire mass. For example, when the tire initial temperature is lower than the reference temperature, the correction value of the heat amount becomes a positive value, and when the tire initial temperature is higher than the reference temperature, the correction value of the heat amount becomes a negative value. However, the correction value does not need to be a strict numerical value that compensates for the temperature difference, and can have a certain range.

In the heating control, a predetermined electric power is supplied to the electromagnetic induction coil 21, the container 1 is heated by the electromagnetic induction coil 21, and the supply of electric power is stopped at a time when the total heat amount in consideration of the correction value is reached. The total amount of heat is adjusted by the electric power to the electromagnetic induction coil 21 or the energizing time.
When the total amount of heat is adjusted by electric power, only the voltage value or the current value is changed while the energization time is kept constant. When the total amount of heat is adjusted by the energizing time, only the energizing time is changed while keeping the power constant. In particular, when the adjustment is made by the energization time, the control is simple because it is only necessary to change the on / off timing of the energization.

FIG. 3 shows an example of a method of controlling the amount of heat supplied to the mold. The horizontal axis represents time (minutes), and the vertical axis represents input power (kW) to the electromagnetic induction coil. In FIG. 3, the hatched portion corresponds to the total amount of heat supplied to the mold, and the area of the hatched portion is changed according to the tire initial temperature.

As described above, if the amount of heat supplied to the mold at the heating station 20 is controlled based on the temperature difference between the initial temperature of the unvulcanized tire T and the reference temperature, the initial temperature of the unvulcanized tire T can be controlled. Can be accurately given to the amount of heat required for vulcanization even if the value differs for each vulcanization.

Therefore, in a multi-mold system for vulcanizing a tire while continuously moving a plurality of containers 1, it is possible to reduce variations in tire quality without changing a preset vulcanization time. it can. Particularly, when the tire forming process by the strip winding method is directly connected to the multi-mold system, a remarkable effect can be obtained.

In the case where tires having the same tire size are continuously vulcanized, the vulcanization time can be fixed.

FIG. 4 shows a flowchart of the heating control when the tire sizes are the same. As shown in FIG. 4, after setting the vulcanization condition of the tire to be vulcanized based on the vulcanization condition document, the mold temperature and the outside air temperature were measured,
Change the vulcanization conditions as needed (Steps S1 to S
3). Next, the temperature of the green tire is measured, and the temperature of the green tire is compared with a reference temperature (steps S4 to S5).

When the temperature of the green tire is higher than the reference temperature in step S5, the heating time of electromagnetic induction is shortened (step S6). At this time, the time to be shortened is obtained from the temperature difference between the temperature of the green tire and the reference temperature.
Then, the container temperature rises based on the electromagnetic induction heating shortened in step S6, and the amount of heat given to the green tire decreases (steps S7 to S8).

On the other hand, if the temperature of the green tire is lower than the reference temperature in step S5, the heating time of electromagnetic induction is lengthened (step S9). At this time, the lengthening time is obtained from the temperature difference between the temperature of the green tire and the reference temperature. Then, based on the electromagnetic induction heating extended in step S9, the container temperature increases, and the amount of heat given to the green tire increases (steps S10 to S11).

Although the amounts of heat applied to the green tires in Steps S8 and S11 are different from each other, the maximum temperatures during vulcanization are substantially the same because the initial temperatures of the green tires are different from each other. (Step S12).

In the above-described embodiment, the container is moved along the container transport device formed in a straight line. In the present invention, the container is moved along the container transport device formed in a loop. You may do it.

[0040]

As described above, according to the present invention, an unvulcanized tire is put into a mold installed in a container, the mold is heated by electromagnetic induction, and then the container is transferred to a vulcanizing station. In the method of performing tire vulcanization, the temperature of the unvulcanized tire to be charged into the mold is measured, a temperature difference with respect to a predetermined reference temperature is obtained, and the amount of heat supplied to the mold is controlled based on the temperature difference. In addition, the amount of heat required for vulcanization can be accurately given to the mold, and as a result, the variation in tire quality can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a multi-mold system for carrying out a tire vulcanizing method of the present invention.

FIG. 2 is a sectional view showing a container of the multi-mold system of FIG. 1;

FIG. 3 is a graph illustrating a method of controlling the amount of heat supplied to a mold.

FIG. 4 is a flowchart of heating control when tire sizes are the same.

[Explanation of symbols]

 Reference Signs List 1 container 2a lower mold (mold) 2b upper mold (mold) 2c sector (mold) 10 opening / closing station 11 tire loader 12 tire unloader 14 infrared thermometer 20 heating station 21 electromagnetic induction coil 30 vulcanization station 40 container transport device T tire

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F202 AH20 AK11 AP05 AR06 CA21 CB01 CY10 4F203 AH20 AK11 AP05 AR06 DA11 DB01 DC15 DK07 DK13 DL14

Claims (3)

[Claims] 1. A method of charging an unvulcanized tire into a mold installed inside a container, heating the mold by electromagnetic induction, and then transporting the container to a vulcanization station to perform tire vulcanization, A tire vulcanization method for measuring a temperature of an unvulcanized tire to be put into the mold, obtaining a temperature difference with respect to a predetermined reference temperature, and controlling a heat amount supplied to the mold based on the temperature difference. 2. When a temperature of the unvulcanized tire is a predetermined reference temperature, a reference calorie required for vulcanization is previously obtained, and a temperature of the unvulcanized tire to be charged into the mold is measured. 2. The tire vulcanizing method according to claim 1, wherein a correction value for the reference heat amount is calculated based on a temperature difference between the tire temperature and the reference temperature, and the correction value is added to the reference heat amount. 3. The tire vulcanizing method according to claim 1, wherein the temperature measurement of the unvulcanized tire is performed at least at one of a bead portion and a tread portion.