Patent Application
20070148270
The present invention relates to a tire curing mould with internal holes, and more particularly, to a tire curing mould with internal holes which is lightweight, and has excellent durability and heat transfer effects, and easy maintenance characteristics.
Generally, a tire for a vehicle includes a tread, shoulders, sidewalls, beads, carcass plies, belts, and so on. A green tire, in which the above components are engaged with each other, is cured through a tire curing process to complete the tire. The tire curing process is a process of mixing a rubber component with a curing agent and applying a predetermined pressure and a predetermined temperature to the mixture to provide elasticity and strength to the tire.
Specifically, the tire curing process is performed by applying high temperature and pressure in a state that the green tire is disposed between a curing mould and a bladder. At this time, typically, the high temperature is transmitted from the curing mould and the bladder, and the pressure is transmitted from the bladder.
The tire curing mould is classified into various types, typically, a segment type divided in a radial direction and a dual type divided into upper and lower halves.
As shown in
In addition, referring to its cross-sectional structure, an inner surface of the mould 1 has a complementary shape to conform to the tread of the tire, and a plurality of vent holes 4 are formed through the mould from the inner surface to an outer surface to discharge inner air during the curing process.
The mould 1 is formed to conform to an outer shape of the tire, without another specific inner component.
The tire curing mould 1 may be made of an aluminum alloy such as JIS AC4D, AC3A, AC7A, and so on.
As shown in
Technical Problem
In the conventional tire curing mould, since stress due to the curing pressure is largely concentrated at a lower side end of the mould (shoulders of the tire), the lower side is likely to be damaged or deformed during repeated operations. As a result, circularity of the tire is remarkably decreased to make it impossible to meet a quality standard.
In addition, since the heat supplied from the exterior of the tire mould is provided from a heat pack disposed at an outer surface of the mould, its heat transfer efficiency is very low.
Further, due to its heavyweight, its handling is very inconvenient, and its material such as an aluminum alloy is very expensive.
Furthermore, since the vent hole passing through in the radial direction is very long, a rubber spread out during the curing process should be periodically removed through the drilling operation, which leads to a decrease of productivity of the tire.
Technical Solution
Therefore, the present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a tire curing mould with internal holes which is lightweight and easy to maintain, and has excellent durability and heat transfer effects.
In order to accomplish the above object, there is provided a tire curing mould with internal holes including a plurality of segment moulds disposed in a circumferential direction of a tire and assembled to each other, and a plurality of holes formed through the segment moulds, wherein each of the segment moulds has a through hole formed in a circumferential direction of the segment mould.
Preferably, at least two through-holes are formed in the segment mould symmetrically about a centerline of a cross-section of the segment mould.
Preferably, the through-hole disposed far from the centerline has a size smaller than that of the through-hole disposed adjacent to the centerline.
In addition, preferably, the through-hole has an oval shape having a long axis in a lateral direction of the tire, or a circular shape.
Preferably, the through-hole has a flat bottom surface approximately parallel to an inner surface of the segment mould.
In addition, preferably, at least one vent hole is formed from the inner surface of the segment mould to the through-hole.
The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:
Reference will now be made in detail to the preferred embodiments of the present invention. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear,
As shown, the tire curing mould with internal holes in accordance with the exemplary embodiment of the present invention includes a plurality of segment moulds 100 disposed in a circumferential direction and assembled to each other. Each segment mould 100 has vent holes 120 formed from its inner surface.
In addition, the segment mould 100 has through holes 110 formed through the mould 100 in a circumferential direction. In this process, preferably, at least two through-holes 110 are formed in a symmetric manner about a centerline of a cross-section of the segment mould 100. At this time, preferably, the through-hole placed far from the centerline, i.e., the through-hole adjacent to a shoulder of the tire has a size smaller than that of the through-hole placed adjacent to the centerline. As a result, it is possible to make the tire lightweight and uniform the stress distribution.
Further, as shown in
In addition, preferably, the vent holes 120 are formed from the inner surface of the segment mould 100 to the through-hole 110. Therefore, during a tire curing process, inner air passes through the vent holes 120 via the through-holes 110 to be discharged through gaps between the segment moulds 100. Since the through-hole 110 has an area several tens of times larger than that of the vent hole 120, the inner air can be more readily discharged.
In addition, it is possible to prevent rubber spread out during the curing process from being stuck in the moulds to thereby making its maintenance convenient,
Of course, several holes of the vent holes 120 may pass through from an inner surface to an outer surface of the segment mould 100, without passing through the through-hole 110.
Meanwhile, a separate heat source (not shown) may be inserted into the through-hole 110. Therefore, since a distance between the green tire and the heat source becomes short, it is possible to increase heat transfer efficiency.
Since the tire curing mould should be operated while engaged with the container 300, a mathematical model of the container 300 is constructed and analyzed with the boundary condition that a profile of the container 300 has perfect confinement (fixed linear and rotational displacement).
In addition, an actually designed curing load, i.e., a pressure of 24 kgf/cm2 is applied to the inner surface of the segment mould 100 in contact with the tread.
As a result of the structure analysis, in the case of the structure of
In addition, in the case of the structure of
As can be seen from the foregoing, a tire curing mould in accordance with the present invention includes a plurality of segment moulds having through-holes disposed in a circumferential direction, whereby it is possible to improve durability and quality of a tire since the stress concentration can be prevented.
In addition, when several vent holes are in fluid communication with the through-holes, inner air can be readily discharged from the mould to prevent the tire from being badly cured and rubber from being stuck in the mould so that its maintenance cost and time can be remarkably reduced.
Further, since separate heat sources can be installed in the through-holes of the segment moulds, and a green tire and the heat source are disposed adjacent to each other, it is possible to increase heat transfer efficiency and minimize curing time. That is, rapid heating and cooling are possible.
Furthermore, the lightweight curing mould is easy to handle and costs associated with manufacturing it from an expensive material (aluminum) can be reduced.
While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment and the drawings, but, on the contrary, it is intended to cover various modifications and variations within the spirit and scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2004-0072426 | Sep 2004 | KR | national |
