JPS63202410A - Molding die for tire - Google Patents

Abstract

PURPOSE:To make it possible to produce tires of multikind and small quantity production type at low cost by a method wherein the molding die of the tires consists of a set of sectors, which are divided in a plurality of pieces in the peripheral direction of the tires, and a plurality of sets of mold plates different in size, which are selectively exchangeable. CONSTITUTION:Sectors 1 for molding the tread part of a tire are divided in a plurality of pieces in the peripheral direction of the tire and form one set and at the same time are assembled annularly. A pair of mold plates to be assembled to the one set of the sectors 1 is not limited to a single kind, in addition to the pair of an upper mold plate 2 and a lower mold plate 3, for example, another pair of an upper mold plate 2' and a lower mold plate 3' having molding surfaces 2a' and 3a' different in size may be prepared so as to allow to mold a tire different in size. Since the sectors 1, the making cost of which is high, are commonly used and the mold plates, which can be made at low cost, are exchangeably assembled to the sectors, tires having a plurality of sizes can be manufactured at low mold cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a tire molding mold that is capable of molding tires of multiple sizes.

[Prior art]

In recent years, user needs for tires have become increasingly diverse, and in addition to their original functions such as supporting loads, running, and turning.
The quality of appearance (fashionability) is also becoming an issue, and the life cycle of a single product is becoming extremely short. For this reason, tire production is becoming increasingly geared toward high-mix, low-volume production.

On the other hand, conventional tire molding molds were mainly divided into two parts, but in recent years, molds that are divided into multiple parts have been developed to improve the uniformity of tires and to form block patterns with good wet road performance. As expensive sectional molds consisting of a combination of cent sectors and a pair of mold plates have come into widespread use, molding molds account for an extremely high proportion of tire development costs.

Therefore, when developing a new type of high-mix, low-volume production tire with a short life cycle as mentioned above, a major technical issue in the industry is how to reduce the cost of the mold. .

[Purpose of the invention]

An object of the present invention is to provide a tire molding die that can produce tires of a high-mix, low-volume production type as described above at low cost.

[Structure of the invention]

To achieve the above object, the present invention mainly consists of a sector that is divided into a plurality of sectors in the circumferential direction of a tire to form one set, and a sector that is assembled on both sides of this set of sectors, mainly to form a tread part. A mold comprising a pair of mold plates for molding a sidewall portion, characterized in that a plurality of pairs of mold plates with different dimensions are configured to be selectively interchangeable in one set of sectors. That is.

The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 and FIG. 2 show a sectional type tire molding mold according to an embodiment of the present invention.
, -, 1 is a sector mainly for forming the tread part of the tire, and these sectors are arranged in multiple sectors in the circumferential direction of the tire (
In this example, it is divided into 7 pieces to form one set,
And, as shown in Fig. 2, it can be assembled into a ring. Each sector 1 has a molding surface 1a for molding a tread pattern of a tread portion and a part of a sidewall portion on the inside thereof, and each sector 1 is adapted to be moved in the radial direction when die-cutting. There is.

On the other hand, 2.3 is a pair of upper mold plates and lower mold plates, which are assembled on both sides of a set of sectors 1, -, 1 assembled in an annular shape as shown in FIG. The pair of upper mold plate 2 and lower mold plate 3 each have molding surfaces 2a and 3a for molding a sidewall portion inside.

In such a sectional type mold, the sector 1 is generally made of aluminum and a complicated trend pattern is formed on the molding surface 1a, so the manufacturing cost is very high. On the other hand, since the pair of upper die plate 2 and lower die plate 3 are simply cut into a disc shape using a lathe, they can be manufactured at a much lower cost than the sector 1. The manufacturing cost ratio of this sector and a pair of mold plates is 13. , about 9:1
There is a difference.

In the tire molding mold of the present invention, in the above-mentioned sectional mold, the pair of mold plates 2゜3 that can be assembled into one set of sectors is not limited to one type, but multiple types with different dimensions. This allows the tires to be interchanged while sharing the same sectors, making it possible to mold multiple types of tires with different sizes. That is, as shown in FIG. 1, a pair of upper die plates 2. In addition to the lower mold plate 3, a pair of upper mold plate 2° and lower mold plate 3'' having molding surfaces 2 a' + 3 a' of different sizes are prepared, and these are attached to the former mold plate 2.3. It can be replaced and installed to make it possible to mold tires of different sizes.

In the present invention, a set of cells as described above.

The number of mold plates that can be made interchangeable with the lid is not limited to two types as in the embodiment, but more pairs may be provided. In addition, the sector mainly molds the tread part, and the mold plate molds the sidewall part, but the boundary of the molding area between this sector and the mold plate is from the position B of the maximum cross-sectional width of the tire T to the trend side. It can be placed in any position on the sidewall. As a result, tires of a plurality of sizes having various tire cross-sectional widths and/or aspect ratios can be molded.

More preferably, in order to stabilize the stress in the carcass line of the tire to be molded, the carcass line C from the maximum width position B of the tire T to the tread side may be made substantially the same for each size of tire. By doing so, unnecessary stress concentration can be eliminated to reduce deformation during tire inflation, and a highly durable tire can be obtained.

In addition, in the present invention, when making multiple pairs of mold plates compatible with a 1 cent sector as described above, the outer diameter D (mm) to be set on the molding surface 1a of the sector 1 is , it is desirable to define as follows. In other words, for tires of multiple sizes formed by replacing multiple pairs of mold plates, the minimum value of the maximum standard outside diameters defined by JATMA, for example, is 5Illin (mm), and the same minimum value is 5Illin (mm). When the maximum value of is SdlmaX (IIlm), [((SD+1111g +5dsax) /
2) -2] ±3 (mm).

More specifically, ((SDsia +5dsax) /2) -5<D
<((SDmta +5dsax) / 2) +
1. Here, the 2 mm subtracted from the above formula is an amount that takes into account the amount that will grow when the tire is made from the mold.

By setting the tire outer diameter of the sector within the above-mentioned range, it is possible to set a mold that has as many standard outer diameters as possible consisting of a plurality of sizes.

Figure 3 shows tire sizes 185/70R13 and 1 with the same tire cross-sectional designation and different aspect ratios in the present invention.
This figure shows the main parts of a mold for molding two types of tires: 85/65R14.

This mold is designed so that upper mold plates 2 and 2' (the paired lower mold plate is not shown) are compatible with sector 1, and when upper mold plate 2 is installed, 1
It is possible to mold an 85/70R13 tire, and when a 2° upper die plate is attached, it is possible to mold a 185/65R14 tire with a lower aspect ratio. [In addition, tire size 185/70R13,
185/65R14 indicates, from the front, the maximum cross-sectional width of the tire (in mm), the aspect ratio (%), the tire structure (R means radial structure), and the inner diameter of the tire (rim diameter in units of 1 inch). There is. ] In this mold, the tire outer diameter set in sector 1 is 594 mm as shown in Figure 3, but this outer diameter was set as follows according to the above formula. It is something.

In other words, according to JATMA regulations, tire size 1
The standard outer diameter of 85/70R13 is set in the range of 582 to 603 mm, and the standard outer diameter of 185/65R14 is set in the range of 589 to 603 mm. Therefore, in the standard outer diameter range defined for each, the minimum value SD, i, of the maximum values of both is 603 crystal (because both are the same), and the maximum value of the minimum values of both is Sd+mmX is 589m-. Half of these values is (603+589)/2-596mm, so the value obtained by subtracting 2m- from this 596mm is 594+
It becomes ++11+.

Therefore, in the above embodiment, the preferred outer diameter is 59
It is sufficient to set it within the range of 4±3IIIl.

In the example shown in FIG. 3, the center of this range, 594s+m, is set.

The tire molding mold of the present invention has a basic structure of a sectional mold as described above, shares a sector which is expensive to manufacture, and prepares a plurality of pairs of mold plates that can be manufactured at a very low cost for this sector. Since they are assembled interchangeably, tires of multiple sizes can be manufactured with low mold costs.

Furthermore, since the mold of the present invention shares sectors as described above, the large number of evaluation steps that must be performed for each tire when developing a new tire can be partially replaced by evaluation of tires of a shared size. You will be able to do this. As a result, the development period for new tires can be significantly shortened, and it is possible to bring about a significant reduction in development costs that goes beyond simply reducing mold production costs.

Additionally, tire manufacturers generally prepare an extra number of tire molds for each size (design) so that they can cover the maximum production volume (maximum demand volume) even at a given time. There is. In the present invention, such countermeasures can be made mutually accommodating by shifting the maximum production period between sectors of common size, so the total number of mold surfaces to be prepared can be significantly reduced. .

〔Effect of the invention〕

As described above, the tire molding mold of the present invention shares one set of sectors, which is expensive to manufacture, and
Since multiple pairs of mold plates, which can be produced at low cost, are interchangeably assembled into the tire, tires of multiple sizes can be produced while significantly reducing mold production costs.

Furthermore, when developing multiple new tires of different sizes, a portion of the evaluation man-hours can be shared, so the development period can be significantly shortened.

In addition, by sharing sectors, the number of extra mold surfaces that need to be prepared in consideration of the maximum production period can be reduced.
This can greatly contribute to reducing production costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a tire molding mold according to an embodiment of the present invention, FIG. 2 is a schematic perspective view showing the same mold in a set state, and FIG. 3 is a schematic diagram showing an embodiment of the same mold. FIG. 3 is a cross-sectional view showing main parts. 1...Sector, 2,2゛...Upper mold plate,
3.3゛...Lower mold plate. Figure 1 Figure 2 Figure 3 a

Claims (3)

[Claims] (1) A sector that is divided into a plurality of sectors in the circumferential direction of the tire to form one set, mainly to form the tread part, and a sector that is assembled on both sides of this set of sectors to mainly form the sidewall part. 1. A tire molding mold comprising a pair of mold plates, wherein a plurality of pairs of mold plates having different dimensions are configured to be selectively interchangeable in one set of sectors. (2) The tire molding according to claim 1, wherein the carcass line of the molding area from the maximum width position to the tread side of each tire molded from one set of sectors and a plurality of pairs of mold plates is mutually common. Mold for use. (3) SDmin (mm) is the minimum value of the maximum standard outside diameters set for tires of multiple sizes formed by exchanging multiple pairs of mold plates, and sdmax is the maximum value of the minimum values. (mm), the tire outer diameter D (mm) set on the molding surface of the sector is {(SDmin+sdmax)/2}-5<D<{(
The tire molding mold according to claim 1, wherein the molding die is set in the range of SDmin+sdmax)/2}+1.