DE102010061184A1 - Vulcanizing mold for vehicle tire, has ventilation unit with valve comprising air removal capillary that is formed in region of inner mold surface, aligned with outer surface of mold surface and exhibits specific breadth and/or diameter - Google Patents

Abstract

The mold (1) has a set of mold segments (2) comprising a ventilation unit that stays in connection with the atmosphere, such that air from a mold cavity of the vulcanizing mold is removed outside by the mold segments. The ventilation unit has a valve comprising a C-shaped air removal capillary formed in a region of an inner mold surface (3) and aligned with an outer surface of the mold surface, where the breadth and/or the diameter of the air removal capillary is less than 0.15 mm. The capillary is formed by cavities that are densely packed with fibers. The fibers are selected from a group comprising glass fibers, mineral fibers, metal fibers and carbon fibers.

Description

The invention relates to a vehicle tire curing mold consisting of mold segments having an inside mold surface and wherein the mold segments have venting means in communication with the atmosphere through which air can be vented outwardly from the mold cavity of the mold through the mold segment.

It is known to provide venting means in Vulkanisierformen to remove the remaining during the Heizpressvorgang of the green tire between the green tire and the molding surfaces during the pressing process of the green tire to the molding surfaces from the mold cavity can. It should be avoided so unwanted defects in the form of bumps on the surface of the tire. During the heating press process, the green tire gets its final contour and is converted by rubber crosslinking reactions in its rubbery state.

It is known that during vulcanization of the vehicle pneumatic tire, rubber material can be pressed or sucked into cylindrical ventilation channels serving as venting means. The resulting sprouts are retained on the finished pneumatic vehicle tire and must be removed before use with specially designed machinery. This so-called "trimming" leads to an extension and increase in the cost of the production process of the pneumatic vehicle tire.

It is also known to form in the mold surface of the vulcanizing mold opening venting channels through drilled recesses, in which lockable vent valves are used. As closable vent valves find so-called "Eurovents" use. A Eurovent is a sleeve made of metal, which for sealing the mold cavity has a valve disc which can be closed against the force of a spring and closes the sleeve end in the plane of the mold surface. This valve avoids the sprouts, since the valve disc closes the venting means in alignment with the mold surface. The disadvantage, however, is that the Eurovent is susceptible to contamination and that under the rim reaching rubber material contaminates the valve, glued and unusable. This detrimental effect is exacerbated by modern rubber blends containing alternative plasticizers.

Since a sufficient number of such venting channels, usually two to three thousand, per Vulkanisierform must be provided to grant sufficient ventilation of a Vulkanisierform, especially in niches of the tire profile, the cleaning or replacement of dirty valves leads to a considerable cost and time ,

It is the object of the present invention to provide a Vulkanisierform for vehicle tires with venting agents, which is less prone to contamination and with which the vehicle tire is vulcanizable with only a small amount of rubber.

This object is achieved by the venting means having a valve with an air discharge capillary, which is arranged in alignment with the surface of the mold surface and the surface of the mold surface and that the Luftabführungskapillare has a width or a diameter of less than 0.15 mm. According to the invention is achieved by the arrangement of a valve with a Luftabführungskapillare function of a capillary, that the flow resistance in this Luftabführungskapillare is high, so that only a small amount of rubber material of the tire to be vulcanized can penetrate into the capillary and the shoots therefore only a small length exhibit. On the other hand, the passage for the air to be discharged is large enough to avoid flaws on the tire surface. Due to its short length during the demolding of the tire, the shoot is completely pulled out of the venting means so that a "self-cleaning" takes place during demoulding. The shoot has such a small length that it visually and the driving characteristics of the tire only insignificantly reduces and thus does not need to be removed. There is provided a Vulkanisierform invention for vehicle tires, which is less prone to fouling and with which the vehicle tire with only a slight rubber ejection is vulcanizable.

In a specific embodiment, the valve has a single Luftabführungskapillare, which has a non-cylindrical shape, preferably the shape of a cuboidal gap and whose width is constant or tapered in the region of the molding surface. The constant width gap has a length of 0.1 mm to 2.5 mm and a width of 0.05 mm to 0.15 mm. In a further embodiment, the valve has two to five Luftabführungskapillaren, preferably three Luftabführungskapillaren, which are preferably arranged parallel to each other.

In another particular embodiment, the venting means comprises a plurality of Luftabführungskapillaren, wherein the Luftabführungskapillare are oriented so that they stand upright on the mold surface.

It is advantageous if the Luftabführungskapillare are formed by the cavities of a dense packing of fibers which have an approximately circular cross-section and each have a diameter smaller than 1.3 mm and which are preferably monofilaments.

It is expedient if the fibers are glass fibers, mineral fibers, metal fibers or carbon fibers. The metal fibers may have a greater coefficient of expansion than the surrounding and surrounding material, whereby a clamping and a tight fit of the metal fibers is achieved.

To avoid rubber adhesion to the fibers, it is advantageous if they are provided with a non-stick coating.

Further features, advantages and details of the invention will be explained in more detail with reference to the drawings, which illustrate schematic embodiments. It show the:

1 a segmented vulcanizing mold with molding segments;

2 a three-dimensional representation of a valve with a single slit-shaped Luftabführungskapillare;

3 a three-dimensional view of a valve with a plurality of Luftabführungskapillaren;

4 a three-dimensional view of a threaded sleeve in which a valve is to be arranged;

5 a three-dimensional representation of another valve with three gap-shaped Luftabführungskapillaren;

6 a three-dimensional view of another valve with a single Luftabführungskapillare as a C-shaped gap.

In the 1 is a simplified schematic representation of a segmented Vulkanisierform 1 for vehicle tires having a plurality of mold segments which can be joined together to form a circumferentially closed mold 2 shown, wherein the mold segments 2 are radially movable and radially inner molding surfaces 3 with a negative tread pattern for forming the positive tread pattern of the tire to be vulcanized 4 exhibit. The mold segments have venting means (not shown) communicating with the atmosphere and through which air is expelled outwardly from the mold cavity of the vulcanizing mold through the mold segment. The mold segments are usually made of steel or aluminum.

The 2 shows a three-dimensional sectional view of a valve 5 a deaerator. The valve 5 has a single air discharge capillary 6 on which in the area of the molding surface 3 and with the surface of the molding surface 3 is arranged in alignment. The air discharge capillary 6 is a cuboid gap and has the shape of a rectangle in supervision. The width b in the area of the molding surface 3 is constant. The air discharge capillary 6 has a length l of 2.0 mm and a width b of 0.1 mm.

The 3 shows a three-dimensional representation of a valve 5 with a variety of air discharge capillaries 6 showing the interstices of a bundle of monofilaments 7 are. The air discharge capillary 6 are oriented so that they are perpendicular to a molding surface 3 get up. The air discharge capillary 6 are through the cavities of the dense packing of monofilaments 7 made of metal. The monofilaments 7 have a roughly round cross-section of less than 1 mm.

The valve of 3 is in a cylindrical threaded sleeve 8th held, 4 , This is the valve 5 easy in the vulcanization mold 1 to assemble and disassemble. The threaded sleeve 8th has at its lower end a recess 9 on, in which for assembly and disassembly in the Vulkanisierform 1 a tool can intervene.

The 5 shows a three-dimensional view of another valve 5 with three slit-shaped Luftabführungskapillaren 6 , The three slit-shaped Luftabführungskapillare 6 have a rectangular cross-section and are arranged parallel to each other. The width b of each Luftabführungskapillare 6 is 0.1 mm and the length l of each Luftabführungskapillare 6 is 2.0 mm.

The 6 shows a three-dimensional view of another valve 5 with a single air discharge capillary 6 , which is exemplified as a C-shaped gap. The width b of the gap is 0.1 mm.

LIST OF REFERENCE NUMBERS

1

vulcanizing mold

2

mold segment

3

form surface

4

tires

5

Valve

6

Luftabführungskapillare

7

monofilament

8th

threaded sleeve

9

recess

b

Width of the air discharge capillary

l

Length of the air discharge capillary

Claims (7)

Vulcanizing mold ( 1 ) for vehicle tires consisting of mold segments ( 2 ), which has an inside molding surface ( 3 ) and wherein the mold segments ( 2 ) Have venting means which communicate with the atmosphere and through which air from the mold cavity of the vulcanization mold ( 1 ) through the mold segment ( 2 ) is passed through to the outside, characterized in that the venting means a valve ( 5 ) with an air discharge capillary ( 6 ), which in the region of the molding surface ( 3 ) and with the surface of the molding surface ( 3 ) is arranged in alignment and that the Luftabführungskapillare ( 6 ) has a width (b) or a diameter of less than 0.15 mm. Vulcanizing mold ( 1 ) according to claim 1, characterized in that the valve ( 5 ) a single air discharge capillary ( 6 ), which has a non-cylindrical shape, preferably the shape of a cuboid gap, and whose width (b) in the region of the molding surface (FIG. 3 ) is constant or rejuvenated. Vulcanizing mold ( 1 ) according to claim 2, characterized in that the valve ( 5 ) two to five air discharge capillaries ( 6 ), preferably three Luftabführungskapillare ( 6 ) having. Vulcanizing mold ( 1 ) according to claim 1, characterized in that the venting means comprises a plurality of Luftabführungskapillaren ( 6 ), wherein the Luftabführungskapillare ( 6 ) are oriented such that they are perpendicular to the molding surface ( 3 ) get up. Vulkanisierform according to claim 4, characterized in that the Luftabführungskapillare ( 6 ) through the cavities of a dense packing of fibers ( 7 ) are formed, which have an approximately circular cross-section and a diameter of less than 0.13 mm and which are preferably monofilaments ( 7 ) are. Vulcanizing mold according to claim 5, characterized in that the fibers ( 7 ) Glass fibers, mineral fibers, metal fibers or carbon fibers are. Vulcanizing mold according to one or more of claims 4-6, characterized in that the surface of the fibers ( 7 ) are provided with a non-stick coating.

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