JPH0347162B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method of molding a hollow rubber product using a core mold with a built-in heating device.
More specifically, unvulcanized rubber is filled into the mold in which the core mold is placed by injection molding, etc.
The present invention relates to a method of molding a rubber product, in which secondary vulcanization is performed, the mold is divided, the core mold is rotated, and secondary vulcanization is performed outside the mold using a heating device built into the core mold.

<Conventional technology> Conventionally, when vulcanizing a rubber-shaped product with a hollow shape by injection molding or the like, first, cavities were carved into the upper and lower molds to match the outer shape of the rubber-shaped product. Prepare the upper mold and lower mold that have been installed, and then prepare a core mold with a shape that matches the hollow part of the product and place it in the corresponding part of the cavity, and then the upper mold, core mold, and lower mold They used molds that were combined to form a cavity.

Then, the cavity of this mold is filled with unvulcanized rubber material, and the rubber material is vulcanized in the mold by heating devices attached to the upper and lower molds, and a rubber molded product is formed. was.

The time required for this vulcanization varies depending on the rubber material and heating temperature, but generally requires several tens of times the material filling time.

<Problems to be Solved by the Invention> However, since the vulcanization of this unvulcanized rubber material is performed in the cavity following the filling of the material, the mold is occupied during the vulcanization of the material. At the same time, the molding machine for filling the material was on standby.

Therefore, there has been a problem in that the operating efficiency of expensive equipment such as molding machines and molds is low, and as a result, the productivity of rubber products is low.

<Means for Solving the Problems> The present invention has been made in view of the above points, and the vulcanization process of hollow rubber products is performed by primary vulcanization in which the outer shape of the product is formed in a mold. The process is divided into a secondary vulcanization process and a secondary vulcanization process performed outside the mold.
While performing the next vulcanization process, the mold clamping process to the primary vulcanization process in the next molding cycle is performed in the mold to shorten the mold occupation time in one molding cycle and to It is designed to perform vulcanization.

That is, the gist of the present invention is a method for molding a rubber mold product using a plurality of core molds each having a built-in heating device, the method comprising: (a) a core mold having a built-in heating device; A plurality of units are prepared, and the core mold of one of the plurality of units is moved between a mold consisting of an upper mold and a lower mold, and the upper mold, core mold, and lower mold are combined to form a mold. a mold clamping step of forming a predetermined cavity in the mold; (b) a rubber material filling step of filling an unvulcanized rubber material into the cavity formed in the mold clamping step; and (c) a mold clamping step of a primary vulcanization step in which the unvulcanized rubber material filled in the cavity is heated to stabilize the outer shape of the rubber product; (d) after the primary vulcanization step, the mold is divided and the core mold (e) the rubber product moved outside the mold is further heated for a predetermined period of time by a heating device built into the core mold; and a secondary vulcanization step, during a predetermined time period of the secondary vulcanization step, mold clamping by the upper mold, a core mold of a separate unit, and the lower mold in the next molding cycle. process and
This is a method for molding a rubber product, which is characterized by performing a rubber material filling step and a primary vulcanization step.

<Example> The method of the present invention will be described below as an example of a method for molding a hollow rubber product 20 using a core-type transfer device 1 based on the drawings.

First, the core type transfer device 1 will be explained.
The core transfer device 1 is formed by an air cylinder 15, a reversing mechanism 7, a core structure 19, and members that connect and support these mechanisms.

In FIG. 1, an upper mold 2 and a lower mold 4 are molds in which cavities 3, 3, 5, and 5 of a predetermined shape are respectively carved, and in this embodiment, they are installed in an injection molding machine (not shown). The upper mold 2 moves downward and the lower mold 4 moves upward, and are combined at an intermediate position.

The air cylinder 15 is disposed at the rear of the mold (that is, at the rear of the molding machine operating section), and the piston rod of the air cylinder 15 has a guide plate 16 and a connecting member 17 and a support member 18 extending forward at both ends thereof.
are arranged around the outside of the mold.

A core structure 19 is disposed at the tip of the connecting member 17 and the support member 18 via a reversing mechanism 7 and a shaft support 14, which will be described later. The child structure 19 is capable of sliding between a predetermined forward position and a predetermined retreat position on a base (not shown).

The reversing mechanism 7 for the core-shaped structure 19 disposed at the tip of the aforementioned connecting member 17 has its supporting member 8 fixed to the connecting member 17, and is slidably disposed on the supporting member 8. This rack 11 and this rack 1
1 and a reversing actuator 9 that drives the pinion 10.

The core mold structure 19 has a plurality of core molds having a predetermined shape, and in the embodiment, two core molds constitute one unit, and the two units are arranged at symmetrical positions with the main shaft member 13 as an axis.

When the air cylinder 15 is in the retracted position,
One unit of the core mold 6 is disposed at a predetermined position within the cavities 3, 3, 5, and 5 of the mold, and the other unit is located outside the mold.

In addition, each core mold 6 has a built-in heating device that heats the surface of the core mold 6 to a predetermined temperature, and when the core mold 6 is in the mold, the unvulcanized rubber is heated outside the mold. They are each configured to heat the primary vulcanized rubber when in position.

Further, a pinion 12 that meshes with the rack 11 is disposed at one end of the main shaft member 13 of the core-shaped structure 19, and a shaft support 14 disposed at the tip of the support member 18 at the other end rotates the shaft member 13. Supported for free movement.

Note that the above-mentioned reversing actuator 9 operates when the air cylinder 15 is in the forward position, that is, when the core mold 6
When both units are located outside the mold, the pinion 12 is driven via the pinion 10 and the rack 11 to rotate the main shaft member 13, and in the embodiment, the main shaft member 13 is rotated by 180 degrees and the core mold is rotated. 6 units to the inverted position.

Next, a method of molding a hollow rubber product using the core-type transfer device 1 having the above-described structure will be described.

First, as shown in FIG. 2, with the air cylinder 15 in the retracted position, the core molds 6, 6, the upper mold 2, and the lower mold 4 are combined to form predetermined cavities 3, 4 in the mold.
A mold clamping process is performed to form cavities 3, 5, 5, and then cavities 3, 3, 5,
A rubber material filling step is performed in which the chamber 5 is filled with an unvulcanized rubber material.

Next, while keeping the mold in this clamped position, the rubber material filled in the cavities 3, 3, 5, 5 is passed through an upper mold 2, a core mold 6, and a core mold 6 for stabilizing the outer shape of the rubber product 20. A primary vulcanization process is performed by heating the lower mold 4. This primary vulcanization process
Vulcanization is carried out to the extent that the outer shape of 0 is stabilized, and in this example, the vulcanization time is approximately half of the conventional vulcanization time.

Next, after moving the upper mold 2 and the lower mold 4 up and down to separate the molds, the air cylinder 15 is activated to move the core mold structure 19 to the forward position.
Core mold movement in which the rubber products 20, 20 whose external shapes have been stabilized after the primary vulcanization process are still fitted into the core molds 6, 6, and the core molds 6, 6 are moved to the outside of the molds. Perform the process (see Figure 3).

At this time, the core molds 6, 6 in which the rubber products 20, 20 are fitted are initially located closer to the cavity than the main shaft member 13, and the core molds 6, 6 without the rubber products 20, 20 are Although it is located on the opposite side of the cavity, when the reversing actuator 9 is operated, the core type structure 19 is moved through the pinion 11.
The main shaft member 1 rotates in the direction shown by the dashed line in FIG.
3 is moved to the opposite side of the cavity.

Then, the rubber products 20, 2 that are fitted are heated by the heating device built into the core molds 6, 6.
0 is further heated to begin secondary vulcanization to form optimal physical properties. Note that this secondary vulcanization process is performed continuously from the primary vulcanization process, and the heating device built into the core mold 6 is also switched on continuously from the primary vulcanization process. Therefore, strictly speaking, there is no boundary between the primary vulcanization process and the secondary vulcanization process, but the heating after the core mold 6 comes out of the mold is the secondary vulcanization process. Further, from this point on, the next molding cycle starts, and between the end of this secondary vulcanization process, the air cylinder 15 is retracted, the core mold structure 19 is moved, and the product is held. A mold clamping step in which the cavities 3, 3, 5, 5 in the next molding cycle are formed by combining different core molds 6, 6, upper mold 2, and lower mold 4, and as described above. A rubber material filling step is performed in which unvulcanized rubber material is filled into the cavities 3, 3, 5, and 5, and a subsequent primary vulcanization step is performed to stabilize the outer shape within the mold. (See Figure 5) During this time, the rubber product 20 located outside the mold,
In No. 20, the secondary vulcanization process progresses, and optimal physical properties are formed in the secondary vulcanization time, which is about half of the conventional vulcanization time, and molding is completed, and the molding is completed from the core molds 6 and 6. The rubber products 20, 20 are removed from the mold.

Note that this secondary vulcanization time can be adjusted using the core mold 6.
heating device and product removal time. Next, divide the mold for the second molding cycle,
The rubber product that has undergone the primary vulcanization process is taken out of the mold, and the secondary vulcanization process of the second molding cycle is started.

In this way, the above steps are performed sequentially,
At the same time, the secondary vulcanization process of the first molding cycle is performed outside the mold, and the same upper mold 2, lower mold 4, and another core mold 6 are
1 from the mold clamping process of the second molding cycle using
Since the steps up to the next vulcanization process are performed within the mold, the mold occupation time is approximately 1/1/2 per molding cycle in this example.
Even if the length is shortened to 2, a hollow rubber product 20 having the same physical properties as the conventional one can be obtained.

In the embodiment, the core-shaped structure 19 is reversed by the reversing mechanism 7 consisting of the reversing actuator 9, but it is also possible to perform the reversal using a rack and pinion mechanism fixed to the base. By combining these, it is also possible to have a rotation mechanism in the same direction. It is also applicable to a combination of core molds of three or more units.

Further, although the core mold is reversed by rotation in a vertical plane, it is also possible to configure the axis of the core mold structure vertically and reverse the core mold by rotating in a horizontal plane.

In the case of this example, a core mold reversing mechanism is installed in the center of two injection molding machines facing each other, and the core mold consisting of four units arranged in a cross shape is rotated 90 degrees at a time. The core mold located at A rubber material filling process is performed, and a primary vulcanization process is performed in which the unvulcanized rubber material is heated to stabilize its external shape as a rubber product. It is desirable to perform a secondary vulcanization step.

<Effects of the Invention> As is clear from the above explanation, according to the method of the present invention, the time occupied by the mold per cycle of hollow rubber products that are continuously molded is shortened, resulting in improved productivity. is significantly improved.

Therefore, it is possible to mold a large amount of products without procuring expensive molding machines or mold equipment.

Also, since the core mold is equipped with a heating device,
Also in the primary vulcanization step, the vulcanization time is shortened and productivity can be improved.

Furthermore, when a rubber molded product is released from the mold, the core mold in which the product is fitted is located outside the mold, so when the product is released from the mold, burrs generated on the rubber product are removed from the mold. The inside of the mold is kept clean, and the next cycle of molding can be started quickly.

[Brief explanation of drawings]

The drawings are explanatory diagrams showing embodiments of the method of the present invention. Fig. 1 is a perspective view of the core-type transfer device used in the invention in an assembled state, and Fig. 2 is an explanatory perspective view showing the primary vulcanization process. Figure 3 is an explanatory perspective view showing the transition to the secondary vulcanization process after the primary vulcanization process, Figure 4 is an explanatory perspective view showing the inversion of the core mold, and Figure 5 is an explanatory perspective view showing the transition to the secondary vulcanization process. It is an explanatory perspective view showing the curing process and the time of the primary vulcanization process of the next molding cycle. 1... Core type transfer device, 2... Upper mold, 4... Lower mold, 3, 5... Cavity, 6... Core mold, 7...
...Reversing mechanism, 19... Core type structure, 20... Product.

Claims (1)

[Scope of Claims] 1. A method for molding a rubber mold product using a plurality of core molds each having a built-in heating device, comprising: (a) using a core mold each having a built-in heating device; A plurality of units are prepared, and the core mold of one of the plurality of units is moved between a mold consisting of an upper mold and a lower mold, and the upper mold, core mold, and lower mold are combined and placed inside the mold. (b) a rubber material filling step of filling an unvulcanized rubber material into the cavity formed in the mold clamping step; (c) a mold clamping step of filling the cavity of the clamped mold with an unvulcanized rubber material; (d) after the primary vulcanization step, dividing the mold,
a core mold moving step of moving the rubber product together with the core mold out of the mold; (e) the rubber product moved outside the mold is further heated by a heating device built into the core mold; a secondary vulcanization step in which the mold is heated for a predetermined period of time; A method for molding a rubber product, comprising a mold clamping process, a rubber material filling process, and a primary vulcanization process.