JPH0733023B2 - Master model for tire mold - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a master model for a tire mold obtained by curing a liquid ultraviolet curable resin by an optical molding method.

[0002]

2. Description of the Related Art The tire tread and the shoulder contact portion of a tire mold are constituted by a tread ring or dread segment manufactured by aluminum casting. In the manufacturing process of this tread ring or dread segment, the original shape of the tire pattern is called a master model for tire mold.

Conventionally, the master model for a tire mold has been manufactured by cutting a plaster block material with an NC type engraving machine or the like. However, it took a lot of time and effort to make it. Therefore, as an attempt to facilitate the production of a master model for a tire mold, for example, the one described in JP-A-61-181616 has been proposed.

In this conventional master model, a plurality of thin plates having the same shape as the cross-sectional shape of the tread portion obtained when the tire is sliced in parallel or perpendicularly to the equatorial plane are superposed in the order of slice positions. It was fixed. The conventional thin plate laminated type master model can shorten the processing time and the like as compared with the one in which solid plaster is NC processed, however, it is difficult to stack and laminate each cross-section thin plate with high accuracy. It was one step.

Therefore, as a method of stacking each cross section with high accuracy, there is, for example, a three-dimensional shape forming method described in Japanese Patent Laid-Open No. 3-2030. In this conventional technique, a liquid ultraviolet curable resin material, which is positioned on the upper surface of a work table with a predetermined thickness, is irradiated with a beam to selectively cure the liquid ultraviolet curable resin material to selectively cure the first ultraviolet curable resin. A layer is formed, and then a liquid ultraviolet curable resin material having a predetermined thickness is placed on the first curable resin layer, and beam irradiation is performed to selectively cure the layer.
The second cured resin layer is laminated on the first cured resin layer, and similarly, the cured resin layers are sequentially laminated in the order of the third, fourth and so on to form a three-dimensional shape. .

If this three-dimensional shape molding method is applied to the preparation of a tire mold master model, it is possible to prepare a highly accurate laminated master model.

[0007]

However, if the above three-dimensional shape forming method is simply diverted to a method for producing a master model for a tire mold, the following problems occur.
In other words, if each layer of the cured resin layer is solid (solid) like the thin plate layer, the internal residual stress generated during curing of each cured resin layer causes distortion of the entire three-dimensional shape, resulting in high distortion. It was difficult to make a master model of accuracy.

Further, when the entire cross section of each layer is cured, a large amount of resin material is required, and the scanning time for laser light irradiation becomes long. Therefore, an object of the present invention is to provide a master model for a tire mold in which distortion due to residual stress of a cured resin layer does not occur, and consumption resin material is reduced and processing time is shortened.

[0009]

In order to achieve the above object, the present invention has taken the following means. That is, a feature of the present invention is that a tire model is created using a three-dimensional CAD database, the tire model is cut into slices of a predetermined thickness, and data of the cross-sectional shape of each slice is created, Based on the shape data, the liquid ultraviolet curing resin is irradiated with a laser beam to be cured into its cross-sectional shape, and the tire mold master model obtained by stacking each fault, and the thickness of each fault is The thickness is 0.05 to 0.3 mm, and the surface thickness of the master model obtained by laminating each fault is 3 to 20 mm.

The master model has a cavity and a reinforcing skeleton having a thickness of 3 to 5 mm.

[0011]

According to the present invention having the above-mentioned structure, since the cross-sectional shape of each fault is not solid but has a cavity and a reinforcing skeleton, the actual cross-sectional area is smaller than that of the solid cross section. Therefore, the residual stress generated in the fault becomes small, the strain becomes small, and the shape retention with high accuracy can be maintained. Furthermore, the consumption of resin material is small, and the processing time is short.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. The master model for tire mold of the present invention is a three-dimensional C
It is made by a stereolithography method in which a liquid ultraviolet curable resin is cured by laser light using AD data. FIG. 2 is a block diagram of a manufacturing apparatus for manufacturing the tire mold master model 1 by the stereolithography method. Since this manufacturing apparatus is the same as the three-dimensional shape molding apparatus described in JP-A-3-2030, the details thereof are incorporated by reference, but the apparatus is a liquid ultraviolet curing resin.
It has a storage container 3 with an upper opening for storing 2. A work table 5 that can be raised and lowered by an elevation drive device 4 is accommodated in the accommodation container 3. A laser beam irradiation device 6 is arranged above the storage container 3. A control device 7 for controlling the lifting drive device 4 and the laser light irradiation device 6 is provided. The control device 7 receives the three-dimensional CAD data created by the computer 8.

The three-dimensional CAD data by the computer 7 is created by the method described in the above-mentioned JP-A-61-181616. That is, as shown in FIG. 3A, first, data of a three-dimensional model 10 of a tire having a predetermined tread pattern 9 is created. Next, the obtained three-dimensional model 10 is divided in the circumferential direction and divided into unit blocks 11 as shown in FIG. Then, it is further divided into two along the equatorial plane 12 to create a unit block 13 as shown in FIG. 3C, and the unit block 13 is sliced (cut) perpendicularly to the tire equatorial plane 12 at a predetermined interval Δh. Then, the cross-sectional shape data of each layer is created. These data are all created by computer.
Done on 7.

In the present invention, the predetermined interval (thickness of each slice) Δh between the slices is set to 0.05 to 0.3 mm. Further, in the present invention, as shown in FIG. 1, the cross-sectional shape of each layer is not solid, and the surface thickness a is 3
~ 20 mm, with a cavity 14 inside and a thickness b of 3-5 mm
Data processing is performed by the computer so that the shape having the reinforcing skeleton 15 is obtained.

The reinforcing skeleton 15 has a hexagonal or octagonal honeycomb shape, but is not limited to this. The three-dimensional CAD data created by the computer as described above is input to the control device 7, and based on the data, the lifting drive device 4 and the laser light irradiation device.
Control 6

That is, a predetermined amount of the liquid ultraviolet curable resin 2 is contained in the container 3, and the work table 5 is separated from the liquid surface of the liquid ultraviolet curable resin 2 by a predetermined interval Δh (0.2 mm in this embodiment) of the slice. Position it just below. Then, the liquid ultraviolet curing resin 2 is irradiated with laser light according to the cross-sectional shape of the first layer. The liquid ultraviolet curable resin 2 in the portion irradiated with the laser light is cured, and a 0.2 mm-thick section is formed.

Next, the work table 5 is lowered by 0.2 mm, laser light is irradiated according to the sectional shape of the second layer, and the resin having the sectional shape is cured. Thereafter, the same operation is repeated to create the tire mold master model 1 in which the respective faults are laminated. Then, the cross-sectional shape of the master model 1 is as shown in FIG. According to the embodiment of the present invention, the cross section of the resin master model 1 is not solid and has the cavity 14 and has the reinforcing skeleton 15, so that the residual stress is smaller than that of the solid one. , The deformation of the entire Master Model 1 becomes extremely small,
It can be highly accurate.

Further, as compared with the solid type, the amount of resin used is smaller, which is economical, and the scanning distance for laser light irradiation is shorter, so that the processing time is shortened and the manufacturing cost is reduced. Planned. According to the stereolithography method, an undercut that cannot be processed by cutting can be processed by the action of the laser. Further, when the molding of stainless steel called a knife blade for forming a fine groove (groove) is designed using the same three-dimensional CAD data, it matches the shape of the master model obtained by the stereolithography method. It is possible to eliminate the conventional problem that the finished knife blade cannot be inserted into the plaster model.

The present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the object of the present invention.

[0020]

According to the present invention, the deformation of the master model due to the residual stress can be prevented, the precision can be improved, the material can be saved, and the processing time can be shortened. The effect is remarkable. Is.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a master model for a tire mold according to an embodiment of the present invention, and is a cross-sectional view taken along the line AA of FIG.

FIG. 2 is a configuration diagram of a manufacturing apparatus for manufacturing a master model for a tire mold according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram of creating three-dimensional CAD data by a computer.

[Simple explanation of symbols]

 1 Master model for tire mold 14 Cavity 15 Reinforcement skeleton

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Claims (2)

[Claims] 1. A tire model is created using a three-dimensional CAD database, the tire model is cut into slices of a predetermined thickness, data of the cross-sectional shape of each slice is created, and based on the data of the cross-sectional shape, A master model for a tire mold obtained by irradiating a liquid ultraviolet curable resin with laser light to cure it into its cross-sectional shape and stacking each section, and the thickness of each section is 0.05 to 0.3 mm. , The master model obtained by stacking each fault has a surface thickness of 3
~ 20 mm master model for tire molds characterized by 2. The master model for tire mold according to claim 1, wherein the master model for tire mold has a cavity and a reinforcing skeleton having a thickness of 3 to 5 mm therein.