JP2013159049A - Tire vulcanizing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire vulcanizing apparatus by which the cycle efficiency of a heating and pressurizing medium in a bladder is increased and a difference in temperature between the lower side and the upper side of a tire can be reduced.SOLUTION: A tire vulcanizing apparatus 1 includes: a medium supply path 2 for supplying a heating and pressurizing medium; a medium discharge path 3 for discharging the heating and pressurizing medium; and a circulation system 4 for the forced circulation of the heating and pressurizing medium. The medium supply path 2 has: several spouts 22 which are opened in the bladder 15; and a medium supply pipe 24 which vertically extends and is provided with a spout 22 in its upper part. The medium discharge path 3 has: a collection port 32 which is opened in the bladder 15; and a medium discharge pipe 34 which vertically extends and is provided with a collection port 32 in its upper part. The summation of opening spaces of the several spouts 22 is 10-50% of the cross section area in the pipe of the medium supply pipe 24. The opening space of the collection port 32 is larger than the cross section area in the pipe of the medium supply pipe 24 and the cross section area in the pipe of the medium discharge pipe 34.

Description

  The present invention relates to a tire vulcanizing apparatus for heat vulcanizing a raw tire in a mold.

  Generally, in tire vulcanization, a raw tire set in a tire vulcanizer is heated and pressurized from the outer surface side of the tire by a mold and heated and pressurized from the inner surface of the tire by a rubber bag-like bladder. Is given. A heating medium such as steam or a pressurized medium such as nitrogen gas is supplied to the bladder through a medium supply path, and the heated and pressurized medium is discharged to the outside of the bladder through the medium discharge path. In the present specification, the term heating / pressurizing medium is used as a general term for the heating medium and the pressing medium.

  Patent Document 1 describes a tire vulcanizing device that circulates a heated inert gas in a bladder with a fan so that heat transfer to a green tire is made uniform. Patent Document 2 describes a tire vulcanizing apparatus including a pump for forcibly circulating a heating and pressurizing medium so that uniform vulcanization of the entire tire is promoted. However, when steam is supplied as a heating medium, drain is accumulated on the lower side of the bladder, and the lower side of the tire tends to be cooler than the upper side. Such a non-uniform temperature distribution could not be sufficiently dealt with.

  If the temperature distribution is not uniform as described above, there will be a difference in the degree of vulcanization between the upper side and the lower side of the tire, and the rubber properties will be unbalanced. It is not preferable. In recent years, there has been a demand for higher performance of high-performance tires such as fuel-efficient tires and run-flat tires, and with the evolution of mixing technology for uniform dispersion of special compounding materials in rubber materials, the level is higher than ever. It is strongly desired to propose a method that can vulcanize the tire uniformly by improving the temperature difference.

JP-A-5-104542 JP-A-62-33611

  The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the circulation efficiency of the heating and pressurizing medium in the bladder and reduce the temperature difference between the lower side and the upper side of the tire. To provide an apparatus.

  The present inventor has conducted extensive research to achieve the above object, and as a result, the opening area of the ejection port in the medium supply path, the cross-sectional area in the pipe of the medium supply pipe, and the opening area of the recovery port in the medium discharge path It has been found that by adjusting the cross-sectional area of the medium discharge pipe in the pipe, the circulation efficiency of the heating and pressurizing medium in the bladder can be improved satisfactorily, and the temperature difference between the upper and lower sides of the tire can be effectively improved. The tire vulcanizing apparatus of the present invention has been made on the basis of such knowledge, and can achieve the above object with the following configuration.

  That is, the tire vulcanizing apparatus according to the present invention includes a mold for heating and pressurizing the raw tire from the outer surface side of the green tire and an inner surface of the raw tire. A bladder for heating and pressing from the tire inner surface side, a medium supply path for supplying a heating and pressing medium to the inside of the bladder, a medium discharging path for discharging the heating and pressing medium to the outside of the bladder, and the medium In the tire vulcanizing apparatus, comprising: a circulation device that forcibly circulates the heated and pressurized medium so that the heated and pressurized medium passing through the discharge path is re-supplied into the bladder via the medium supply path. The supply path has a plurality of ejection openings opened inside the bladder, and a medium supply pipe extending in the vertical direction and provided with the ejection openings at the upper part thereof, and the medium discharge path is The inside of the bladder A recovery port that is open, and a medium discharge pipe that extends in the vertical direction and is provided with the recovery port at an upper portion thereof, and the sum of the opening areas of the plurality of ejection ports is equal to that of the medium supply pipe. It is 10 to 50% of the sectional area in the pipe, and the opening area of the recovery port is larger than the sectional area in the pipe of the medium supply pipe and the sectional area in the pipe of the medium discharge pipe.

  According to such a configuration, the sum of the opening areas of the plurality of ejection ports is less than half of the cross-sectional area in the medium supply pipe, thereby increasing the flow rate of the heating and pressurizing medium ejected into the bladder. At the same time, since the opening area of the recovery port is larger than the cross-sectional areas in the medium supply pipe and the medium discharge pipe, the flow velocity for sucking the heated and pressurized medium from the recovery port can be set small. As a result, the circulation efficiency of the heating and pressurizing medium in the bladder can be improved, and the temperature difference between the lower side and the upper side of the tire can be reduced, contributing to uniform vulcanization of the tire.

  In the present invention, it is preferable that the ejection port is configured to be directed obliquely downward and to eject the heated and pressurized medium toward the lower shoulder portion of the green tire. By jetting the heating medium toward the lower shoulder portion of the tire where the temperature drop due to the drain is remarkable, the upper and lower temperature difference in the tire can be further effectively improved.

  In the present invention, it is preferable that a header covering the upper ends of the medium supply pipe and the medium discharge pipe is detachably provided, and the ejection port and the recovery port are formed in the header. According to this configuration, the header in which the ejection port and the recovery port are formed is detachably provided, so that the number and direction of the ejection ports, the opening area of the ejection port and the recovery port, the ejection port and the recovery port The distance to the mouth can be changed relatively easily, and this is useful for adjusting the magnitude relationship with the cross-sectional area of the medium supply pipe and medium discharge pipe.

  In the present invention, it is preferable that the ejection port and the recovery port are arranged with an interval in the vertical direction. According to such a configuration, it is possible to increase the effect of reducing the temperature difference between the lower side and the upper side of the tire by increasing the region in which the heated and pressurized medium can circulate inside the bladder.

Sectional drawing which shows an example of the tire vulcanizing apparatus which concerns on this invention Perspective view of header

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a tire vulcanizing apparatus 1 for heat vulcanizing a raw tire 9 in a mold 10. The tire vulcanizing apparatus 1 includes a mold 10 that is assigned to the outer surface of the raw tire 9 to heat and press the raw tire 9 from the outer side of the tire, and an inner surface of the raw tire 9 that is attached to the inner side of the raw tire 9. A bladder 15 for heating and pressurizing, a medium supply path 2 for supplying a heating and pressing medium to the inside of the bladder 15, a medium discharge path 3 for discharging the heating and pressing medium to the outside of the bladder 15, and a heating process And a circulation device 4 for forcibly circulating the pressure medium.

  The mold 10 includes a tread mold portion 11 addressed to the tread surface of the raw tire 9, a lower mold portion 12 addressed to the lower tire outer surface, and an upper mold portion 13 addressed to the upper tire outer surface. . These are configured to be freely displaceable between a mold-clamping state and a mold-opening state by an opening / closing mechanism (not shown) installed around, and the structure of such an opening / closing mechanism is well known. The mold 10 is provided with a platen plate (not shown) having a heat source such as an electric heater or a steam jacket, whereby each mold part is heated.

  A central mechanism 14 is provided at the center of the mold 10, and a tread mold part 11, a lower mold part 12, and an upper mold part 13 are installed around the center mechanism 14. The central mechanism 14 includes a rubber bag-like bladder 15 addressed to the inner surface of the raw tire 9, an upper clamp 17 that grips the upper end of the bladder 15, and a lower clamp 18 that grips the lower end of the bladder 15, The medium supply path 2 and the medium discharge path 3 described above are provided. Inside the bladder 15, a temperature sensor and a pressure sensor (both not shown) are installed.

  The medium supply path 2 includes a plurality of ejection openings 22 opened inside the bladder 15 and a medium supply pipe 24 extending in the vertical direction and provided with the ejection openings 22 on the upper part thereof. A heating medium is sent from the heating medium supply source 23 to the medium supply path 2 according to the opening / closing operation of the valve 25, and a pressurized medium is sent from the pressing medium supply source 26 according to the opening / closing operation of the valve 28. Further, as will be described later, the heating and pressurizing medium re-supplied by the circulation device 4 is also fed into the medium supply path 2.

  The medium discharge path 3 includes a collection port 32 opened inside the bladder 15 and a medium discharge pipe 34 extending in the vertical direction and provided with the collection port 32 at an upper part thereof. A blow valve 33 for opening and closing is attached to the medium discharge pipe 34. The operations of the valves 25 and 28 and the blow valve 33 are controlled by a control circuit (not shown) according to the detection result by the temperature sensor.

  The circulation device 4 keeps the pressure in the bladder 15, so that the heated and pressurized medium passing through the medium discharge path 3 is re-supplied into the bladder 15 via the medium supply path 2. Has the function of forced circulation. An example of such a circulation device is a gas circulation unit manufactured by Ichimaru Giken Co., Ltd. The circulation device 4 is configured by a pump, for example, and can be configured such that the high-temperature and high-pressure fluid circulates by a differential pressure between the medium supply path 2 and the medium discharge path 3.

  The central mechanism 14 is detachably provided with a header 5 that covers the upper ends of the medium supply pipe 24 and the medium discharge pipe 34. The header 5 includes a plurality of ejection ports 22 and a collection port as shown in FIG. 32 is formed. In a state where the header 5 is attached to the central mechanism 14, the ejection port 22 communicates with the medium supply pipe 24, and the recovery port 32 communicates with the medium discharge pipe 34. A ring-shaped space 51 that communicates with the medium supply pipe 24 is provided inside the header 5, and the heated and pressurized medium is ejected radially from the ejection port 22 through the space 51.

  In the tire vulcanizing apparatus 1, the sum of the opening areas of the plurality of ejection ports 22 is set to 10 to 50%, more preferably set to 10 to 30% of the cross-sectional area in the pipe of the medium supply pipe 24. Yes. When this ratio is 50% or less, the flow rate of the heating and pressurizing medium ejected into the bladder 15 can be increased satisfactorily. In addition, when this ratio is 10% or more, a required amount of the heating and pressing medium can be supplied into the bladder 15 without affecting productivity.

  Further, in the tire vulcanizing apparatus 1, the opening area of the recovery port 32 is larger than the in-pipe cross-sectional area of the medium supply pipe 24 and the in-pipe cross-sectional area of the medium discharge pipe 34. The flow rate for sucking the heating and pressurizing medium can be set small. In the case where a plurality of recovery ports are provided, it is sufficient that the total sum thereof is larger than the above-described cross-sectional area in the pipe. The opening area of the recovery port 32 is, for example, formed with a size of 100 to 300% of the cross-sectional area in the medium supply pipe 24 and the medium discharge pipe 34.

As an example, the diameter of each ejection port 22 is 4 mm, the number of ejection ports 22 is 12, the opening area of the collection port 32 is 500 mm ² , the inner diameter d2 of the medium supply pipe 24 is φ20 mm, and the medium discharge pipe 34 A configuration in which the inner diameter d3 is φ20 mm can be given. In this case, the sum total of the opening areas of the ejection ports 22 is 48πmm ² , which is 48% of the cross-sectional area in the pipe of the medium supply pipe 24 of 100πmm ² . The opening area of the recovery port 32 is larger than the pipe cross-sectional area 100Paimm ² medium supply pipe 24 is larger than the pipe cross-sectional area 100Paimm ² of medium discharge pipe 34.

  The diameter of one ejection port 22 is, for example, 2 to 10 mm, and the number of ejection ports 22 is, for example, 6 to 32. The inner diameter d2 of the medium supply pipe 24 is, for example, 12 to 34 mm, and the inner diameter d3 of the medium discharge pipe 34 is, for example, 12 to 34 mm.

  The ejection port 22 may be in the horizontal direction, but is preferably configured to be directed obliquely downward as shown in FIG. 1 and to eject the heated and pressurized medium toward the lower shoulder portion 9 s of the raw tire 9. . By jetting the heating and pressurizing medium toward the lower shoulder portion 9s where the temperature drop due to the drain is remarkable, the upper and lower temperature difference in the raw tire 9 can be further effectively improved. The ejection port 22 is preferably positioned below the equator 9e of the raw tire 9, but is not limited thereto.

  In the present embodiment, a plurality of ejection ports 22 are arranged at equal intervals along the circumferential direction of the columnar header 5, and the ejection ports 22 and the recovery ports 32 are vertically spaced D as shown in FIG. Is arranged. Thereby, the area | region which a heating-pressurization medium can circulate inside the bladder 15 is increased, and the effect of reducing the temperature difference between the lower side and the upper side of the raw tire 9 can be enhanced. From the viewpoint of enhancing the effect, the interval D is preferably 25 mm or more, and is set to 25 to 100 mm, for example. The interval D can be increased by increasing the height of the header 5 itself.

  Next, a procedure for vulcanizing and molding the raw tire 9 using the tire vulcanizing apparatus 1 will be briefly described. First, as shown in FIG. 1, the raw tire 9 is mounted in the mold 10, and the raw tire 9 is shaped close to the inner shape of the mold 10 by the expanded bladder 15. Thereby, the raw tire 9 is held by the bladder 15 addressed to the tire inner surface side, and each of the tread mold part 11, the lower mold part 12, and the upper mold part 13 is addressed to the tire outer surface side. .

  The mold 10 is preheated with a steam jacket or the like, and the raw tire 9 is heated from the tire outer surface side. After shaping the raw tire 9, a high-temperature heating medium (for example, a heating gas such as steam) is supplied into the bladder 15 through the medium supply path 2 to heat the raw tire 9 from the tire inner surface side. When the heating medium is supplied for a predetermined time, a pressurized medium (for example, an inert gas such as nitrogen gas) is supplied into the bladder 15. The raw tire 9 is pressurized at a high pressure from the tire inner surface side by the bladder 15 and is pressed from the tire outer surface side by the mold 10 by the reaction force.

  When the pressurized medium is supplied for a predetermined time, the operation of the circulation device 4 is started, and the heated pressurized medium is forcedly circulated. The heated and pressurized medium sucked from the recovery port 32 is transferred to the medium supply path 2 by the circulation device 4 in the middle of passing through the medium discharge path 3, and is resupplied to the inside of the bladder 15 through the medium supply path 2. The

  In this apparatus, the sum of the opening area of the ejection port 22 and the sectional area in the pipe of the medium supply pipe 24 satisfy the above relationship, and the opening area of the recovery port 32, the sectional area in the pipe of the medium supply pipe 24 and the medium discharge By satisfying the above relationship with the in-pipe cross-sectional area of the pipe 34, in the step of supplying the heating and pressurizing medium, the flow rate of the heating and pressurizing medium ejected into the bladder 15 is increased while the recovery port 32 The flow rate for sucking the heating and pressurizing medium can be set small. As a result, the circulation efficiency of the heating and pressurizing medium in the bladder 15 can be improved, and the temperature difference between the lower side and the upper side of the tire 9 can be reduced.

  If the temperature distribution in the bladder is non-uniform, it takes time until vulcanization is completed at the low temperature of the raw tire, whereas in the present invention, the temperature difference between the upper and lower sides is reduced as described above. Since the temperature distribution in the bladder 15 can be made sufficiently uniform, the vulcanization time can be shortened and the productivity can be improved, and the rubber physical properties are not unbalanced between the upper side and the lower side of the raw tire 9, and the tire performance can be improved. Adverse effects can be suppressed. In addition, since the maximum temperature tends to decrease due to the uniform temperature distribution, the supply amount of the heating medium can be increased to shorten the vulcanization time.

  The present invention is not limited to the embodiment described above, and various improvements and modifications can be made without departing from the spirit of the present invention.

  In order to show the configuration and effects of the present invention specifically, vulcanization of a tire for a passenger car (tire size: 195 / 65R15) is performed, and the size of the ejection port and the recovery port is changed to lower and upper the tire. The temperature difference at was investigated. The temperature difference was detected by a temperature sensor affixed to the surfaces of the lower shoulder portion and the upper shoulder portion of the raw tire, and the result of Comparative Example 1 was evaluated with an index of 100. In vulcanization, steam (saturated steam) was used as a heating medium, and nitrogen gas was used as a pressurizing medium. The evaluation results are shown in Table 1.

  As shown in Table 1, in Comparative Examples 1 to 4, the temperature difference between the upper side and the lower side of the tire was relatively large, whereas in the example, the opening areas of the ejection port and the recovery port were skillfully adjusted. Thus, the temperature difference between the upper and lower sides of the tire can be effectively reduced.

DESCRIPTION OF SYMBOLS 1 Tire vulcanizer 2 Medium supply path 3 Medium discharge path 4 Circulation apparatus 5 Header 9 Raw tire 10 Mold 11 Tread mold part 12 Lower mold part 13 Upper mold part 15 Bladder 22 Blowout port 24 Medium supply pipe 32 Recovery port 34 Medium discharge piping

Claims (4)

A mold for heating and pressurizing the raw tire from the outer surface side of the green tire, a bladder addressed to the inner surface of the raw tire and for heating and pressing the raw tire from the inner surface of the tire, and the bladder A medium supply path for supplying a heated and pressurized medium to the inside of the machine, a medium discharge path for discharging the heated and pressurized medium to the outside of the bladder, and a heated and pressurized medium passing through the medium discharge path as the medium supply In a tire vulcanizing apparatus comprising a circulation device that forcibly circulates a heated and pressurized medium so as to be re-supplied to the inside of the bladder via a road,
The medium supply path has a plurality of ejection openings opened inside the bladder, and a medium supply pipe extending in the vertical direction and provided with the ejection openings at the upper part thereof,
The medium discharge path has a recovery port that is opened inside the bladder, and a medium discharge pipe that extends in the vertical direction and is provided with the recovery port at the top thereof.
The sum total of the opening areas of the plurality of ejection ports is 10 to 50% of the sectional area in the pipe of the medium supply pipe, and the opening area of the recovery port is the sectional area in the pipe of the medium supply pipe and the medium A tire vulcanizing apparatus characterized in that it is larger than the cross-sectional area in the pipe of the discharge pipe.   The tire vulcanizing apparatus according to claim 1, wherein the ejection port is directed obliquely downward and ejects a heated and pressurized medium toward a lower shoulder portion of the green tire.   The tire vulcanizing apparatus according to claim 1 or 2, wherein a header covering the upper ends of the medium supply pipe and the medium discharge pipe is detachably provided, and the ejection port and the recovery port are formed in the header. The tire vulcanizing apparatus according to any one of claims 1 to 3, wherein the ejection port and the recovery port are arranged with a space in the vertical direction.

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