JP2003245923A - Vulcanizing mold for rubber molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vulcanizing mold for a rubber molded article wherein the generation of clogging of an air-discharging passage due to a plug material is reduced, and at the same time, of which the washing is easy. <P>SOLUTION: A porous air vent 15 having numerous pores 15S are embedded in a plurality of holes 14S which are formed on respective pieces 14 of this vulcanizing mold 10 for the rubber molded article. On the internal surface side of the cavities of the porous air vent 15, semi-circular lid members 17 and 17 having a spring function for opening/closing the apertures of the pores 15S are attached. At the time of vulcanization, the apertures of the pores 15S are closed with the lid members 17 and 17. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber molded article vulcanization mold for vulcanizing rubber molded articles such as tires.

[0002]

2. Description of the Related Art When forming a tire, pressure is applied to the inside of a molded raw tire to press the outside surface of the raw tire against the inner wall of a heated mold, and the raw rubber is applied with heat and pressure. A vulcanizing mold for vulcanization (hereinafter referred to as a mold) is used. This mold has exhaust passages such as micro vents, slits, vent holes, and cross vents in order to remove the air trapped between the tire outer surface and the mold and the gas generated from the raw tire during vulcanization. It is provided. However, when the above-mentioned micro vent, vent hole, and cross vent are used, the rubber material enters the vent hole during molding, and many rubber protrusions called spew are formed on the surface of the vulcanized tire. However, trimming was indispensable because it would damage the appearance of the tire. In addition, even if trimming is performed, variations in the cut height may occur or there may be uncut portions, which is not preferable for the appearance of the tire and also requires trimming equipment.
It was a cost increase. In addition, since the vent holes are clogged on the mold side due to spewing, it is necessary to remove them with a tool such as a drill.However, since the mold has several hundred vent holes, the removal work is It was tough. The cross vent has a problem that it cannot be removed even by using a tool or the like. In addition, a film-like protrusion called a lip occurs at the slit, which is not preferable in terms of tire appearance. In addition, if a large lip that crosses the tire main groove is generated, it will become a factor to block the drainage by making the main groove that acts as a drainage dam, so especially when running on a wet road surface, hydroplaning is induced. Problems such as safe driving also occur.

Therefore, as a mold that does not require the trimming step, it has a porous member formed by forming a large number of pores through which only a gas passes in a base material such as a metal or a large number of voids such as a sintered metal. A mold using a porous air vent provided with a porous member made of a porous body has been developed. FIGS. 7A to 7C are views showing a configuration example of a rubber molded product vulcanizing mold 10P including a conventional porous member. The rubber molded product vulcanizing mold 10P includes a plurality of segments 11. An opening 12 for inserting a raw tire to be vulcanized and a rubber material (bladder) for supplying heat and pressure is formed in the shaft core portion of the mold 10P. There is. The segment 11 is
It is composed of an outer case 51 made of steel and a plurality of pieces 52 made of aluminum fixed to the inside of the outer case 51 with bolts or the like (not shown). The surface of the piece 52 (exposed to the inner surface of the mold 10P is exposed). The portion) is the tire forming surface, that is, the portion to which the rubber of the raw tire to be vulcanized adheres. Each of the pieces 52 is formed with a plurality of holes 52S communicating with exhaust holes described later provided in the outer case 51, and each of the holes 52S is shown in FIGS. 8A and 8B. So the outer case 5
A plurality of vent pieces (hereinafter referred to as porous air vents) 53 in which a large number of straight pores 53S having a diameter of 10 to 40 μm and communicating with one exhaust hole 51S are formed are buried. In addition, in FIG. 8B, the upper side (the piece 52 side) of the drawing is the rubber side, and the lower side (the outer case 5).
1 side) is the mold side. Thereby, the mold 10
The air between P and the outer surface of the tire, and the gas generated from the raw tire during vulcanization are exhausted by the exhaust means (not shown) such as a vacuum pump connected to the exhaust hole 51S. And is discharged from the exhaust hole 51S of the outer case to the outside of the mold 10P through a gap 54 provided between the piece 52 and the outer case 51.

[0004]

However, in the above-mentioned conventional porous air vent 53, as shown in FIG.
Since the diameter of the pores 53S is constant from the cavity side to the opposite side (outer case 51 side), fumes such as oil and various chemicals and metals released from the raw tire during vulcanization are provided on the cavity side. When the plug material p such as fine particles of polymer, carbon or the like is clogged, it is difficult to discharge the plug material p to the exhaust side (outside the mold 10P). If the plug material p adheres to the cavity side of the pore 53S in a crocodile shape, the air vent channel becomes narrower, and the plug material p is more likely to adhere, and eventually a bridge is formed to close the pore 53S. This significantly reduces exhaust efficiency, resulting in early tire failure. Therefore, the mold 10P needs to be frequently washed, and the operating efficiency of the mold 10P is poor. Further, in the porous member, once the plugging occurs, it is extremely difficult to remove the plugged plug material with a drill or the like. Since the voids that are formed are not straight, a special cleaning method must be used, which makes it difficult to clean the mold. Further, when a sintered metal is used as the porous member, there is a problem in that a trace of the vent mesh (patch) appears on the tire surface and the appearance is impaired.

The present invention has been made in view of the conventional problems, and an object of the present invention is to provide a vulcanization mold of a rubber molded product which reduces the occurrence of clogging of the exhaust passage due to the plug material and is easy to clean. And

[0006]

A rubber molded article vulcanizing mold according to claim 1 of the present invention has an opening at one end opening to the inner surface of the cavity, and the other end communicating with an exhaust hole of the mold. A vulcanization molding of a rubber molded product having an air vent in which an exhaust passage is formed, wherein the opening is opened and closed on the inner surface side of the cavity of the air vent, and at the time of closing, the opening of the exhaust passage is formed. A movable valve that forms a minute gap between the two is closed, the movable valve is closed during vulcanization, and the plug material is restricted from entering the exhaust passage.
It reduces clogging in the exhaust passage and eliminates spews.

A rubber molded article vulcanization mold according to a second aspect of the present invention is characterized in that the movable valve is composed of a flat plate-like lid member having a spring function for urging in the opening direction. By suction by the exhaust means of
It is possible to restrict the intrusion of the plug material into the exhaust passage by closing the exhaust passage by attracting the lid member to the air vent side. Further, at the time of cleaning, since the lid member is opened by the spring function, the inside of the exhaust passage can be easily cleaned.

In the rubber molded article vulcanization mold according to the third aspect, the air vent is a porous air vent provided with a porous member having a large number of pores through which only a gas passes.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the basic configuration of the rubber molded product vulcanizing mold 10 according to the present embodiment is the same as that of the conventional rubber molded product vulcanizing mold 10P, and a plurality of segments 11 are assembled into a substantially cylindrical shape. Opening 1 for inserting rubber material (bladder)
Have two. As shown in FIG. 2, the segment 11 includes an outer case 13 made of steel and a plurality of aluminum pieces 14 fixed to the inner side of the outer case 13 by bolts or the like (not shown). The surface (portion exposed on the inner surface of the mold 10) is a tire forming surface, that is, a portion to which the rubber of the raw tire to be vulcanized adheres. Each of the pieces 14 is formed with a plurality of holes 14S communicating with an exhaust hole, which will be described later, provided in the outer case 13, and a porous air having a large number of pores 15S formed in each of the holes 14S. The vent 15 is buried. As shown in FIG. 3, the pore 15S communicates with the exhaust hole 13S of the outer case 13 via a gap 16 provided between the piece 14 and the outer case 13. A filter 20 for removing rubber powder and the like and a vacuum pump (VP) 21 for sucking air in the mold 10 and gas generated during vulcanization are connected to the exhaust hole 13S.

In this example, as shown in FIGS. 2 and 3, a spring function for opening and closing the opening of the fine hole 15S is provided on the inner side of the cavity of the porous air vent 15 (the tire forming surface side). Semicircular lid member 17 having
Is installed. As the lid members 17 and 17,
For example, it can be realized by attaching a leaf spring having a spring function, which is biased so as to open toward the tire forming surface side, to the outer peripheral portion of the porous air vent 15. As shown in FIG. 4 (a), the strength of the spring is such that the distance H by which the free ends 17 c of the lid members 17, 17 in the open state protrude to the tire forming surface side (upper side in the figure) is H ≦ 1 mm. It is preferable to adjust so that Further, since the fine hole 15S communicates with the exhaust hole 13S through the space 16 as described above, the vacuum pump (VP) 21 is operated at the time of vulcanization, so that FIG. As shown, the lid members 17, 17 are sucked toward the side of the porous air vent 15 to close the openings of the pores 15S, or the lid members 17, 17 are closed by bladder pressing. Even if a rubber bite occurs in the lid members 17 and 17, since it is discharged as a rubber protruding from the inside of the tire after vulcanization and becomes a part of the tire, it is not deposited in the pores 15S. When the lid members 17, 17 are closed, the lid members 17,
17 and the opening of the fine hole 15S, the distance is 0.5.
A minute gap G having a size of μm or less is formed. The gap G may be formed, for example, by forming a thin film layer on a part of the back surface (on the side of the porous air vent 15) of the lid members 17, 17 by sputtering and using this as a spacer portion. The spacer portions may be formed by removing a part of the peripheral portions of the back surfaces of the lid members 17 and 17 by etching or the like. Alternatively, the lid member 17 may be a circular lid member and processed by the above-mentioned sputtering, etching, and the like.

Therefore, at the time of vulcanization, as shown in FIG. 4B, the plug material p larger than the gap G does not reach the opening of the fine hole 15S, and only the plug material smaller than the gap G is formed. It is taken into the pores 15S. The small plug material easily passes through the pores 15S of the porous air vent 15 and is discharged to the outside of the mold 10 from the exhaust holes 13S of the outer case through the voids 16. Therefore, the frequency of clogging of the pores 15S can be significantly reduced, and the exhaust efficiency can be improved. Further, since the porous air vent 15 of this example limits the exhaust path to the pores 15S by the gap G, spews are hardly generated, and therefore, there is an advantage that the trimming step is not required.

Further, in this example, since the lid members 17 and 17 are provided, the plug material does not adhere to the vicinity of the openings of the pores 15S, and after vulcanization, the lid members 17 and 17 form the tire. Since the openings of the pores 15S are opened by opening to the surface side, the mold 10 can be easily washed. In the mold 10 of this example, the lid member 1
If 7, 7 is damaged or lost, the lid member 17,
Repairing is easy because only 17 needs to be replaced. When the pores 15S are clogged due to damage to the lid members 17, 17, it is desirable to replace the porous air vent 15.

As described above, in this embodiment, the semicircular lid members 17 and 17 having a spring function for opening and closing the openings of the pores 15S are provided on the inner surface side of the cavity of the porous air vent 15. At the time of mounting and vulcanization, since the opening of the fine hole 15S is closed by the lid members 17 and 17, the frequency of clogging of the fine hole 15S can be significantly reduced and the exhaust efficiency is improved. In addition to the above, it is possible to mold a tire with extremely few spews and lips. Also, the lid member 1
Because of Nos. 7 and 17, the plug material does not adhere to the vicinity of the opening of the pore 15S, so that the mold 10 can be easily washed.

In the above embodiment, the case where the two lid members 17 having a semicircular diameter are used has been described.
However, the number of the lid member 17 is not limited to this, as long as it can cover the openings of the pores 15S during vulcanization, and the number and shape of the lid member 17 depend on the size and shape of the mold 10 or the porous air vent 15. It may be determined appropriately. Further, although the porous air vent 15 is described in the above example, a homogeneous air vent 31 having stepped exhaust pores 31S as shown in FIGS. 5A and 5B and FIG. Tapered exhaust pore 32S as shown in a)
Homogeneous air vent 32 provided with, further, FIG.
The present invention can also be applied to a homogeneous air vent 33 provided with exhaust holes 33S having screw grooves as shown in (b). In this case, as the lid member, in any case, the circular lid member 30 processed by the above-mentioned sputtering, etching or the like can be used. Furthermore, in the case of using such a circular lid member 30 that has been processed by sputtering, etching, etc., as shown in FIG.
It can also be applied to a homogeneous air vent 34 having straight exhaust holes 34S as shown in FIG.

[0015]

As described above, according to the present invention,
A rubber molded article vulcanization mold having an air vent having an opening at one end opening to the inner surface of the cavity, and the other end having an exhaust passage communicating with the exhaust hole of the mold, wherein the cavity of the air vent is On the inner surface side, a movable valve that opens and closes the opening and forms a minute gap with the opening of the exhaust passage when closed is provided. Since the intrusion of the plug material is restricted, it is possible to reduce the clogging of the air vent, improve the exhaust efficiency, and mold the tire with extremely few spews and lips. . Moreover, since the plug material does not adhere to the exhaust passage, the mold can be easily washed.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of the configuration of a vulcanization mold for a rubber molded product according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a segment of a rubber molding vulcanization mold according to the present embodiment.

FIG. 3 is a partial cross-sectional view showing a configuration of a segment of a rubber molded product vulcanizing mold according to the present embodiment.

FIG. 4 is a diagram for explaining the operation of the movable valve according to the present embodiment.

FIG. 5 is a view showing another example of the vulcanization mold for the rubber molded product according to the present invention.

FIG. 6 is a view showing another example of the rubber molding vulcanization mold according to the present invention.

FIG. 7 is a diagram showing a configuration of a vulcanization mold for a rubber molded product using a conventional porous air vent.

FIG. 8 is a diagram showing a configuration of a conventional porous air vent.

FIG. 9 is a schematic view showing a clogging state in a conventional porous air vent.

[Explanation of symbols]

10 rubber molding vulcanization mold, 11 segments, 1
2 openings, 13 outer case, 13S exhaust hole, 14
Piece, 14S Piece hole, 15 Porous air vent, 15S Pore, 16 Void, 17 Lid member, 20
Filter, 21 vacuum pump, G gap part.

Claims (3)

[Claims] 1. A rubber molding vulcanization mold having an air vent, which has an opening at one end that opens to the inner surface of the cavity, and the other end that has an exhaust passage communicating with the exhaust hole of the mold. On the inner side of the cavity of the air vent, while opening and closing the opening, when closing,
A rubber molding vulcanization mold, characterized in that a movable valve is provided which forms a minute gap with the opening of the exhaust passage. 2. The rubber molding vulcanization mold according to claim 1, wherein the movable valve is composed of a flat plate-like lid member having a spring function of urging in the opening direction. 3. The rubber molding according to claim 1 or 2, wherein the air vent is a porous air vent having a porous member having a large number of pores that allow only gas to pass therethrough. Product vulcanization mold.