JPH0349737B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a mold used for molding a ring-shaped molded product such as an O-ring made of rubber or synthetic resin, and particularly relates to a mold used for molding a ring-shaped molded product such as an O-ring made of rubber or synthetic resin. This invention relates to a mold used when injection molding a ring-shaped molded product using a machine.

(Prior Art) Various methods have been considered for molding ring-shaped molded products, but rubber or synthetic resin O-rings are often injection molded using an injection molding machine.

When injection molding such a ring-shaped molded product such as an O-ring, a mold consisting of a fixed mold 1 and a movable mold 2 as shown in FIG. 7 has conventionally been used. The fixed mold 1 and the movable mold 2 are provided with ring-shaped grooves 3 and 4 at opposing positions of the mold mating surfaces 1a and 2a, respectively. A ring-shaped cavity corresponding to the shape is formed. That is, the ring-shaped molded product is molded in a state parallel to the mold matching surfaces 1a and 2a of the fixed mold 1 and the movable mold 2.

(Problems to be Solved by the Invention) However, in such a mold, if a plurality of molded products are to be molded at the same time, a plurality of molds will be formed on the mold mating surfaces 1a and 2a of each mold 1 and 2. It is necessary to provide ring-shaped grooves 3 and 4.
Therefore, the mold matching surfaces 1a and 2a must have a large area. for that,
As the mold becomes larger, the mold clamping mechanism of the injection molding machine also needs to be larger. On the other hand, when molding an O-ring, for example, the volume of the mold cavity is small, so the volume of the injection cylinder may be small. As a result, the injection molding machine has a mold clamping mechanism, an injection cylinder, etc. that are significantly unbalanced, and must be treated as a special-purpose machine.

Further, especially when molding a rubber O-ring or the like, since the molded product is soft, it is difficult to remove it from the mold using an automatic machine. Therefore, the molded product must be removed from the mold manually. In that case, in a mold that is configured to mold a plurality of molded products in a state parallel to the mold matching surfaces 1a and 2a as described above, after opening the mold, one molded product can be molded while maintaining that state. You have to take them out one by one. In other words, it takes a long time to take out the molded product, but during that time it is not possible to move on to the next molding cycle. As a result, the time required for one cycle of molding becomes long.

The present invention was made in view of these problems, and its purpose is to enable a general-purpose injection molding machine to mold a large number of ring-shaped molded products at the same time. The purpose is to shorten the time required for a molding cycle.

(Means for solving the problem) In order to achieve this object, the present invention includes a fixed mold, a movable mold, and a core mold to constitute an injection mold for a ring-shaped molded product. I have to.

The fixed mold and the movable mold are provided with mold surfaces having a concave cross section that form a linear cylindrical space opening on the outer surface when the molds are mated, at positions facing each other on the respective mold mating surfaces. In addition, a core mold has a plurality of columnar cores arranged radially around the rotation axis and extending in a direction perpendicular to the rotation axis. It is rotatably supported around the axis of rotation. Each core is sandwiched between the respective mold surfaces of the fixed mold and movable mold when the molds are matched, and forms a ring-shaped cavity between the outer peripheral surface and each mold surface. It is said that

(Function) With this configuration, the ring-shaped cavity is formed in a direction perpendicular to the mold mating surfaces of the fixed mold and the movable mold. Therefore, even if the mold mating surfaces have a small area, a large number of ring-shaped cavities can be formed.

In addition, according to such molds, after injecting material into the cavities to form a ring-shaped molded product, when the fixed mold and movable mold are opened,
The molded product is left behind on the core side. Therefore, the core mold is rotated around the axis of rotation, the core with the molded product attached is positioned outside the fixed mold and the movable mold, and the other core is placed between the mold surfaces of the fixed mold and the movable mold. to be located. Then, by closing and clamping the fixed mold and the movable mold, the next molding cycle can be started. Meanwhile, in the meantime,
The molded product can be removed from the core. Therefore, the time required for taking out the molded product is no longer included in the molding cycle, and the molding cycle is shortened.

(Example) Hereinafter, an example of the present invention will be described using the drawings.

In the drawings, FIG. 1 is a partially cutaway plan view showing one embodiment of an injection mold according to the present invention, and FIG.
The figure is a side view thereof. Moreover, FIGS. 3 to 5 are plan views of the mold in each step for explaining the molding process of a ring-shaped molded product using the mold.

As is clear from FIGS. 1 and 2, this injection mold 10 is composed of a fixed mold 11, a movable mold 12, and a core mold 13. Fixed type 11
is a fixed platen 15 integrated with the bed 14 of the injection molding machine.
is attached to. Further, the movable mold 12 is attached to a movable platen 16 that is supported horizontally movably on the bed 14 of the injection molding machine. The movable platen 16 is moved back and forth relative to the fixed platen 15 by a mold opening/closing device (not shown).

The fixed mold 11 is provided with a mold surface 17 extending horizontally along the mold matching surface 11a facing the movable mold 12. This mold surface 17
has a semicircular concave cross section with its central axis on the mold matching surface 11a, and both ends thereof reach both left and right side surfaces of the fixed mold 11. On the other hand, the mold matching surface 12a of the movable mold 12 is also provided with a mold surface 18 having a semicircular cross section similar to the mold surface 17 of the fixed mold 11.
These mold surfaces 17 and 18 are arranged to face each other. In this way, the fixed mold 11 and the movable mold 1
When mold matching 2 and 2, these mold surfaces 1
7 and 18 form a cylindrical space 19 (see FIG. 3) that opens on both left and right sides of the fixed mold 11 and the movable mold 12.

Each mold surface 17, 18 of the fixed mold 11 and the movable mold 12
A large number of mold grooves 20, 20, . . . ; 21, 21, . The mold grooves 20 of these fixed molds 11
The mold grooves 21 of the movable mold 12 are continuous with each other when the fixed mold 11 and the movable mold 12 are matched. Inside the fixed mold 11, sprues 22 are provided which communicate with the mold grooves 20, 20, . . . , respectively. That sprue 2
2 is an injection cylinder (not shown) of an injection molding machine.
A molding material such as molten rubber injected from the pipe is guided.

The core mold 13 is cylindrical and has a radius equal to each of the mold surfaces 17 and 18 of the fixed mold 11 and the movable mold 12, and has a horizontal support shaft 2 at its longitudinal center.
3 are integrally attached. Its support shaft 2
3 has a rotation axis perpendicular to the longitudinal axis of the core mold 13, and both ends thereof are connected to the fixed mold 11.
The movable mold 12 is rotatably and slidably supported by brackets 24, 24 provided in a protruding manner on the side surfaces of the movable mold 12, respectively. Further, flanges 25, 25 are provided at both ends of the support shaft 23, and coil springs 26, 26 are mounted in a compressed state between the flanges 25, 25 and the brackets 24, 24, respectively. In this way, the core mold 13
is supported rotatably around a rotation axis perpendicular to the longitudinal axis at the outside of the fixed mold 11 and the movable mold 12 by a support member consisting of a support shaft 23 and brackets 24, 24, and is always supported by a support member consisting of a support shaft 23 and brackets 24, 24. 11 and the movable mold 12.

As shown in FIG. 1, the core mold 13 is
When in the horizontal state, one end thereof is always positioned between the mold surfaces 17 and 18 of the fixed mold 11 and the movable mold 12, and when the fixed mold 11 and the movable mold 12 are matched in this state, Each mold side 1
It is designed to be sandwiched between 7 and 18.
That is, both sides of the support shaft 23 of the core mold 13 are connected to the mold surfaces 17, 1 of the fixed mold 11 and the movable mold 12.
The first and second cores 27 and 28 are inserted between the cores 8 and 8. On the outer peripheral surface of each core 27, 28, a mold groove 2 having a semicircular cross section is provided, which faces the mold grooves 20, 21 provided on each mold surface 17, 28, respectively.
9 and 30 are provided. In this way, mold surface 1
When the fixed mold 11 and the movable mold 12 are matched with the core 27 or 28 between them,
Between the outer peripheral surfaces of the cores 27, 28 and the mold surfaces 17, 18, there are a large number of ring-shaped cavities 31, each having a circular cross section.
31, . . . (see FIG. 3) are formed.

The core mold 13 is of such a length that it is located above the bed 14 even when it is in the vertical position as shown in phantom lines in FIG. Therefore, the core mold 13 can be rotated 360 degrees around the support shaft 23.

Next, a procedure for molding a ring-shaped molded product using the mold 10 configured as described above will be described.

First, as shown in FIGS. 1 and 2, the core mold 13 is rotated to a horizontal state, and the first core 27
The mold surfaces 17 and 18 of the fixed mold 11 and the movable mold 12
be located in between. Next, the movable platen 16 is moved to the fixed platen 15 side by the mold opening/closing device, and the fixed mold 11 and the movable mold 12 are closed and further clamped. Then, as shown in FIG. 3, the mold matching surfaces 11a and 12a of the fixed mold 11 and the movable mold 12 come into close contact with each other, and the mold surfaces 17 and 18 and the outer peripheral surface of the core 27 come into close contact with each other. do. A large number of ring-shaped cavities 31, 31, . . . are formed between each mold surface 17, 18 and the outer peripheral surface of the core 27. Then, the injection cylinder of the injection molding machine is operated to inject the molten material. Then, the material is
It is press-fitted into each cavity 31, 31, . . . through the sprue 22 of the fixed mold 11. As a result, a molded article having a shape corresponding to the cavity 31 is molded.

When the injection molding is completed, the mold opening/closing device is operated again, the movable platen 16 is moved back, and the fixed mold 11 and the movable mold 12 are opened, as shown in FIG. Then, the first core 27 is attached to the fixed mold 11
It is separated from both mold surfaces 17 and 18 of the movable mold 12 and is located in the center between them. Then, molded products 32, 32, . . . formed into a ring shape are formed.
is left behind on the first core 27 side.

In this state, the core mold 13 is rotated 180 degrees. Then, as shown in FIG.
7 is located outside of the fixed mold 11 and movable mold 12 with the molded product 32 attached, and the second core 28 is positioned between the mold surfaces 17 and 18 of the fixed mold 11 and movable mold 12. Become. So, we closed the mold again,
The mold grooves 20 and 21 of each mold surface 17 and 18 and the second core 2
The material is injected into the ring-shaped cavity 31 formed by the mold groove 30 on the outer circumferential surface of No. 8 to perform injection molding of the next molded product. And in the meantime, the first
The molded products 32, 32, . . . attached to the core 27 are removed. In that case, the molded products 32, 32,...
Since it can be removed simply by moving the first core 27 in the longitudinal axis direction, the operation is easy.

After the molded product 32 on the first core 27 side is removed and the molded product 32 is molded on the second core 28 side, the mold is opened again and the core mold 13 is rotated 180 degrees. After that, the same cycle is repeated.

In this way, the first core 27 and the second core 28
As a result, the molded products 32 are continuously molded. Since the molded product 32 can be removed during the molding, there is no need to include the time required for removing the molded product 32 in the molding cycle. Therefore, the time required for the molding cycle is shortened.

By the way, in the above embodiment, the core mold 13 has two cores 27 and 28 arranged radially around the support shaft 23 at an interval of 180 degrees. The core mold 13 has three cores arranged radially at intervals of 120 degrees, and one has four cores arranged radially at intervals of 90 degrees. etc. can also be used.

FIG. 6 is a partially cutaway plan view showing another embodiment of the present invention using a core mold having four cores. In this embodiment, the same parts as in the embodiment shown in FIGS. 1 to 5 are given the same reference numerals.

In this embodiment, the bed 14 of the injection molding machine includes two fixed plates 15,
15 are provided. In addition, these fixed plates 1
Two movable plates 16, 16 that are movable back and forth are provided opposite to the plates 5, 15. These movable plates 16, 16 are simultaneously moved back and forth by one mold opening/closing device.

Each fixed platen 15, 15 and movable platen 16, 16 have a fixed type 11, 11 and a movable type 12, respectively.
12 is attached. These fixed mold 11 and movable mold 12 are similar to those in the above embodiment, and have mold surfaces 17, 18 and mold grooves 20, 21, respectively. Each fixed mold 11, 11 and movable mold 12, 12
are integrally connected by brackets 24, 24, respectively. And that bracket 2
4 and 24, a support shaft 23 is rotatably and slidably supported. This support shaft 23 has a core mold 13
is integrally fixed. This core mold 13 is
The coil springs 26, 26 installed between the flanges 25, 25 at both ends of the support shaft 23 and the brackets 24, 24 keep the molds 11, 11 fixed at all times.
and the movable molds 12, 12.

The core mold 13 consists of four cores arranged radially around a support shaft 23 at intervals of 90 degrees, that is, two cores located on the same axis.
It has two first cores 27a, 27b and two second cores 28a, 28b perpendicular thereto.
Each of the cores 27a, 27b; 28a, 28b is similar to the cores 27, 28 of the above embodiment, and has a large number of mold grooves 29, 30 formed on its outer peripheral surface.

A mold 10 consisting of the fixed molds 11, 11, the movable molds 12, 12, and the core mold 13 configured in this way.
In this case, the core mold 13 is rotated to form the first core 2.
When the cores 7a and 27b are positioned between the mold surface 17 of each fixed mold 11 and the mold surface 18 of the movable mold 12 and the molds are closed, a ring-shaped cavity is formed on the outer peripheral side of each core 27a and 27b. Ru. Therefore, by injecting the molten material into the cavity, a ring-shaped molded product 32 is molded. In this way, molding can be performed simultaneously on both sides of the core mold 13.

When the mold is opened after completion of molding, the molded product 32 is separated from the fixed mold 11 and the movable mold 12 and left behind on the first cores 27a and 27b. Therefore, the core mold 13 is rotated 90 degrees. Then, the second cores 28a and 28b are positioned between the fixed mold 11 and the movable mold 12, and the second cores 28a and 28b are positioned between the fixed mold 11 and the movable mold 12, and
The cores 27a and 27b are in a state of vertically protruding. Therefore, the next molding cycle can be started using the second cores 28a, 28b, during which time the molded product 32 can be removed from the first cores 27a, 27b.

Thus, according to this embodiment, the core mold 13
The molded product 32 is molded on both sides of the molded product 32, and the molded product 32 is removed in the meantime, so that more molded products 32 can be obtained in one molding cycle.

In addition, as in this embodiment, four cores 27
Core mold 13 having a, 27b, 28a, 28b
and two fixed molds 11, 11 and two movable molds 12, 1.
When using a mold 10 consisting of 2, one fixed plate 15 and movable plate 16 are provided in a direction of 90 degrees with respect to the other fixed plate 15 and movable plate 16,
Adjacent cores 27a, 28a or 27b, 2
It is also possible to mold the molded product 32 in step 8b. If you do that, the core mold 13
By rotating 180 degrees, while molding is performed using two adjacent cores 27b and 28b, molded product 3 is formed from other two adjacent cores 27a and 28a.
2 can be removed. Therefore, the positions where the molded product 32 is to be removed are concentrated on one side, making the work even easier.

In the above embodiment, an annular molded product 32 with a circular cross section, such as an O-ring, is molded, but the present invention is not limited to this, and can also be applied when molding a square ring-shaped molded product with a rectangular cross section, etc. can also be applied. In such a case, the mold grooves 20, 2
1, 29, and 30 are not necessarily provided on both the fixed mold 11, the movable mold 12, and the core mold 13, and may be provided only on one side.

Further, brackets 24, 24 for supporting the support shaft 23 of the core mold 13 are provided on the fixed mold 11 and the movable mold 12;
4 and 24 may also be provided on the bed 14. In that case, when the mold is opened, the core mold 1
3 is biased so that it is located in the center between the fixed mold 11 and the movable mold 12, and the core mold 13 is pressed and moved by the movable mold 12 when the mold is closed. Bye.

(Effects of the Invention) As is clear from the above description, the present invention provides a fixed mold and a movable mold provided with a mold surface that forms a cylindrical space by fitting the molds, and the mold surface. A ring-shaped cavity is formed between the outer circumferential surface of the core and the mold surfaces of the fixed mold and the movable mold. , the cavity is perpendicular to the mold matching surfaces of the fixed mold and the movable mold. Therefore, even if the mold mating surfaces of the fixed mold and the movable mold have a small area, it is possible to provide a large number of ring-shaped cavities. As a result, a large number of ring-shaped molded products can be produced simultaneously using a small mold. This makes it possible to use a general-purpose injection molding machine.

In addition, since the core mold is composed of a plurality of cores arranged radially around the central axis and is supported rotatably around the central axis, after molding, By rotating the core mold, subsequent molding and removal of the molded product can be performed simultaneously. Therefore, the molding cycle is shortened and
It becomes possible to efficiently mass-produce ring-shaped molded products.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway plan view showing an embodiment of an injection mold for a ring-shaped molded product according to the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a mold of the mold. Fig. 4 is a plan view showing the mold in the closed state, Figure 4 is a plan view showing the mold opened after molding the molded product, and Fig. 5 is the plan view showing the mold opened after molding the molded product. FIG. 6 is a partially cutaway plan view showing another embodiment of the injection mold according to the present invention, and FIG. 7 is an example of a conventional mold for molding a ring-shaped product. FIG. DESCRIPTION OF SYMBOLS 10... Mold, 11... Fixed mold, 11a... Mold mating surface, 12... Movable mold, 12a... Mold mating surface, 13...
Core mold, 17, 18... mold surface, 19... cylindrical space, 2
0, 21...Mold groove, 23...Support shaft (support member), 2
4... Bracket (supporting member), 27, 28... Core,
29, 30... mold groove, 31... ring-shaped cavity,
32... Molded product.

Claims (1)

[Scope of Claims] 1. A fixed mold in which mold surfaces with concave cross-sections that extend linearly along the mold matching surfaces and that open on the outer surface when the molds are matched are provided facing each other. and a movable mold, and a columnar core that is sandwiched between the respective mold surfaces of the fixed mold and the movable mold and forms a plurality of ring-shaped cavities between the outer circumferential surface of the core and the respective mold surfaces. A plurality of core molds are arranged radially around a rotational axis perpendicular to the longitudinal axis of the core, and the core molds are rotated around the rotational axis on the outer side of the fixed mold and the movable mold. A mold for injection molding a ring-shaped molded product, comprising: a support member that freely supports the product;