JPH1190960A - Molding tool and molding method for rubber product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding tool and a molding method for a rubber product for improving the release properties of the rubber product manufactured by molding from the molding tool and also improve the flash removing workability and the manufacturing quality of the rubber product. SOLUTION: A molding tool 1 for molding a product section by a method of injecting a flowing rubber-like elastic material into a cavity CV is provided with a top force 3 having the cavity CV, a gate section 5 and a spool section 6 disposed in said order starting from a parting line PL in the mold opening direction, and an umbrella-shaped valve V1 (a product section) and a spool section 6 combined integrally are retained on the top force 3 at the time of mold opening, the umbrella-shaped valve V1 is released from a bottom force 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die for molding a rubber product and a method for molding a rubber product using the molding die. .

[0002]

2. Description of the Related Art Various methods have been conventionally proposed as a method for molding a product made of a rubber-like elastic material.
FIG. 4 shows a molding die 100 for explaining an example of a molding method.
FIG. 2 is a view schematically showing a cross-sectional configuration and a molding method of the present invention.

[0003] This molding method is one of the most commonly employed, and is a molding method called compression molding.
FIG. 4A shows a state in which the upper mold 101 and the lower mold 102 are opened, and a cavity CV for molding an umbrella-shaped product (umbrella-shaped valve V1) is formed in each mold.

[0004] In the compression molding, a rubber cloth RS as a material measured without excess or shortage is placed on a mold opening surface of a mold 100 that has been opened, and a predetermined amount is set so as to be in a state shown in FIG. The mold is closed at the speed of. When closing the mold, it is necessary to make the rubber cloth RS flow so as to fill all the inside of the cavity CV, and the molding die 100 is heated.

In such compression molding, a thin burr B1 is formed around the umbrella portion V1a of the umbrella-shaped valve V1 on the parting line PL, which is the opening surface of the upper mold 101 and the lower mold 102. When performing multi-cavity cutting of V1, each umbrella-shaped valve V1 is connected by a burr B1, and at the end of molding, the umbrella-shaped valve V1 as a product is released together with the burr B1.

[0006] Such a release method is employed when it is difficult to release the product due to reasons such as a minute product shape, a complicated shape and a large release resistance.

Further, as shown in FIG. 4C, which is an enlarged view of a portion D101 in FIG. 4B, an annular ring B2 having a circular cross section is formed around the umbrella portion V1a via a cut portion B3. By doing so, when the umbrella type valve V1 and the burr B1 are manually separated, a part of the burr B1
To prevent it from remaining.

In addition, when the number of multi-cavities increases, a finishing method of setting and punching in a punching jig may be adopted.

[0009]

However, when the release resistance determined by the size and shape of the product increases, even if the product is released together with the burr, only the burr is cut from the cut portion, and the product is cut off. Mold release becomes difficult.

[0010] This is because the thickness of the burr is set to about 0.05 mm for a product for which a deburring operation is to be performed manually, so that the burr and the product can be easily separated. .

Therefore, in order to prevent cutting at the cut portion during mold release, the thickness t of the burr (cut portion) (FIG. 4)
When the thickness of (b) is increased, the deburring work by hand becomes more difficult as the thickness of the burr becomes thicker, and problems such as defective burr remaining and chipping are more likely to occur.

Further, when the method of punching with a punching jig is adopted, since the product is a rubber-like elastic body having an undefined shape (meaning that it is easily deformed by bending), it takes time and effort to set. Low workability.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to improve the releasability of a rubber product from a molding die by molding, to improve deburring workability and rubber. An object of the present invention is to provide a molding die and a method for molding a rubber product, which can improve the production quality of the product.

[0014]

In order to achieve the above object, according to the present invention, a pair of dies for forming a product portion by cavities divided by a dividing surface, and a gate portion provided in the cavities are provided. And a spool part for injecting a rubber-like elastic material flowing through the cavity into the cavity, wherein one of the pair of molds includes:
Cavity, gate part,
It is characterized in that the spool sections are arranged in order.

With this molding die, it is possible to hold the product portion and the spool portion integrally joined to one mold, and to release the product portion from the other mold by opening the mold.

It is also preferable that the strength of the connection between the product part and the spool part by the gate part is set to be larger than the release resistance of the product part from the other mold which occurs when the mold is opened after molding.

With this configuration, it is possible to reliably prevent the product portion and the spool portion from being cut and separated at the gate portion when the mold is opened.

In the above-described method for molding a rubber product using a molding die, a rubber-like elastic material flowing from a spool portion is injected into a cavity of a closed molding die to form a product portion. The product part is released from the other mold, and the product part and the spool part are held in a state where the product part and the spool part are integrally connected to one mold. Thereafter, the product part or the spool part is separated from the one mold, and the product part is separated at the gate part. And the spool part are separated, and the product part and the spool part are separated from the one mold.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A molding die 1 to which the present invention is applied will be described below.
Will be described with reference to FIG. The molding die 1 in this embodiment is for molding the same umbrella-shaped valve V1 (product part) as that shown in FIG. 4B as a product. However, the shape of the product molded by the molding die 1 is an umbrella-shaped valve V
It is not limited to one, and it can be molded into other arbitrary shapes.

FIG. 1 is a cross-sectional configuration explanatory view showing a state in which a flowable rubber-like elastic material is held in a cavity CV of a molding die 1 and vulcanization molding is being performed, and a plate die 2 constituting the molding die 1 is shown. The upper mold 3 as one mold and the lower mold 4 as the other mold are all in a mold closed state.

First, the structure of the mold 1 will be described. The mold 1 has a substantially three-layer structure as shown.
Incidentally, at the time of actual molding, other components such as a molding die holder and a pressurizing / heating plate (not shown) are also required, but here, only the characteristic configuration of the molding die 1 of the present invention is shown. I have. In the figure, one umbrella-type valve V
1 is shown as a configuration, but in practice only a part of the multi-cavity configuration is shown.

The upper die 3 and the lower die 4 are provided with cavities CV (cavity surfaces CV1 to be described later) for forming an umbrella-shaped valve V1.
And a cavity surface CV2). The cavity CV can be vertically divided in the figure by a parting line PL as a dividing surface, and the umbrella type valve V1 can be released when the upper die 3 and the lower die 4 are open.

The upper die 3 has a cavity surface CV1, a gate portion 5 connected to the cavity surface CV1, and a gate portion 5
Part 6 for injecting a rubber-like elastic material flowing into the cavity CV from the parting line PL
Are arranged in order from the mold opening direction (upper side in the figure).

The gate portion 5 is a constricted portion between the cavity CV and the spool portion 6 as shown in FIG.
The cross-sectional area when cut along a plane parallel to the parting line PL is smaller than the projected area of the cavity CV and the spool portion 6 with respect to the parting line PL.

The lower mold 4 has a cavity surface CV2. The shape of the cavity surface CV2 is deeper than the shape of the cavity surface CV1 and is less likely to be released because the shape of the handle of the umbrella-shaped valve V1 is formed. Conversely, since the cavity surface CV1 forms an open umbrella portion, the cavity surface CV1 has a shape that can be more easily released than the cavity surface CV2.

The plate mold 2 has a spool formed by sandwiching a rubber-like elastic material between the upper mold 3 and moving and compressing the rubber-like elastic material in the direction of the upper mold 3 while heating and fluidizing the rubber-like elastic material. Cavity C from gate section 5 through section 6
A rubber-like elastic material can be injected into the V.

Accordingly, the rubber-like elastic material of the mold 1 in the closed state has a shape in which the spool 6 and the umbrella-shaped valve V1 are connected by the gate 5. A thick burr 7 is formed between the plate mold 2 and the upper mold 3 by overflowing an extra rubber-like elastic material. In addition, Cavity C
The gap between the mating surfaces of the V parting lines PL is set as small as possible to suppress the occurrence of thin burrs around the umbrella.

Next, a molding process for molding the umbrella-shaped valve V1 using the molding die 1 will be described with reference to FIG. Figure 2
(A), (b)... (F) are performed in this order.

(Step 1) Upper die 3 and lower die 4 of molding die 1
Is closed, and the plate mold 2 is opened. A cloth R1 made of a rubber-like elastic material is placed between the plate mold 2 and the upper mold 3 (see FIG. 2A).

(Step 2) The dough R1 is heated and fluidized, and the plate mold 2 is moved in the upper mold 3 direction to apply pressure to the dough R1, and the cavities CV from the gate 5 through the spool 6. The fluidized rubber-like elastic material is injected and filled therein (see FIG. 2B).

(Step 3) After holding and cooling for a predetermined time in the state of FIG. 2 (b), and after the rubber-like elastic material is solidified, the plate mold 2 is opened (see FIG. 2 (c)). The lower mold 4 is opened (see FIG. 2D). Incidentally, the umbrella type valve V1, which is a product, is exposed first,
The order of opening the plate mold 2 and the lower mold 4 can be performed in the lower mold 4 first.

When the mold is opened, the spool portion 6 is connected to and integrated with the umbrella type valve V1 via the gate portion 5, so that the spool portion 6 can be brought into close contact with the plate mold 2; And the umbrella type valve V1 does not remain in the lower mold 4.

(Step 4) From the upper mold 3 to the spool unit 6
And the umbrella type valve V1 are released. In this embodiment, first, as shown in FIG. 2E, the thick burr 7 and the spool portion 6 are pulled in the direction of arrow A1, and the gate portion 5 is released from the upper die 3 as a cutting portion. Thereafter, the handle portion of the umbrella-shaped valve V1 is pinched and pulled in the direction of arrow A2 to release the umbrella-shaped valve V1. Although it is related to the product shape, it is also possible to release the product by air blowing as shown by an arrow A3 toward the recess of the spool portion 6 of the upper die 3. It is also possible to improve efficiency.

Accordingly, by adopting the mold configuration according to the molding die 1 and adopting the molding method described above, the spool portion 6 is connected to the umbrella valve V1 via the gate portion 5 at the stage of opening the mold.
It is not necessary to increase the burr thickness of the parting line PL in order to release the umbrella type valve V1 from the lower die 4 which is securely held on the upper die 3 side and is difficult to release because it is connected with and integrated with the upper die 3. , Umbrella type valve V1 parting line PL
It is possible to reduce burr residue and chipping failure in the part.

FIG. 3 is a view for explaining the shape of the gate portion 5. The spool portion 6 and the umbrella-shaped valve V1 do not separate due to the mold opening, and are easily separated and separated in the subsequent releasing step (step 4). The shape is set so that it can be released, but the diameter in this embodiment is 20 to 30 m.
The umbrella-shaped valve V1 having a length of about m has a cross-sectional shape of φ1.2 mm and an axial length of 0.2 mm. However, the shape of the gate portion 5 is also changed depending on the strength of the material and the adhesion to the mold, and it is necessary to set an appropriate value.

[0036]

According to the present invention, it is possible to easily release a rubber product from a molding die by molding, to improve the deburring workability by making small and thin burrs generated in the rubber product, and By suppressing the occurrence of chipping defects due to the removal, the productivity and production quality of the rubber product can be improved.

[Brief description of the drawings]

FIG. 1 is a view for explaining a mold and a product according to an embodiment of the present invention.

FIG. 2 is a diagram of a method for manufacturing a rubber product using a mold according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a shape of a gate unit according to the embodiment of the present invention.

FIG. 4 is a view for explaining a molding die and a product according to the related art.

[Explanation of symbols]

 Reference Signs List 1 Molding die 2 Plate die 3 Upper die (one die) 4 Lower die (the other die) 5 Gate part 6 Spool part 7 Thick burr CV Cavity CV1, CV2 Cavity surface PL Parting line R1 Fabric V1 Umbrella valve (Product Part)

Claims (3)

[Claims] 1. A pair of molds for forming a product part by cavities divided by a dividing surface, and a spool part for injecting a rubber-like elastic material flowing through a gate part provided in the cavities into the inside of the cavities. A cavity, a gate portion, and a spool portion, which are arranged in this order on one of the pair of dies in a mold opening direction from a dividing surface thereof. 2. The bonding strength between the product part and the spool part by the gate part is set to be larger than the release resistance of the product part from the other mold which occurs when the mold is opened after molding. The mold according to 1. 3. A method for molding a rubber product using the molding die according to claim 1 or 2, wherein a rubber-like elastic material flowing from a spool portion is injected into a cavity of the closed molding die. Molding the part, releasing the product part from the other mold by opening the mold,
The product part and the spool part are held in a state where the product part and the spool part are integrally joined to one of the molds. Thereafter, the product part or the spool part is separated from the one mold, and the product part and the spool part are separated at the gate part. A rubber product from the one mold.