JP2003001683A - Injection-molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection-molding die which is almost free from the breakage of an angular cam sheet or a cam pin and the wear of a cam groove and consequently, can easily secure a transfer of a slide core over a long distance, even in the molding die using the slide core. SOLUTION: This injection-molding die 1 comprises a cavity side part 2 and a movable part 3 and has a hollow part to be undercut, formed in a cavity during clamping and molding. In the cavity side part 2, the cam groove 231 is formed penetrating the angular cam sheet 23 and a cam plate 23. In the movable part 3, a slide core 36 for forming a hollow part to be undercut is provided and has a cam pin 361 to be inserted into the cam groove 231, so that the cam pin 361 is movable along the cam groove 231. Besides, on the outer periphery of the cam pin 361, a roller 362 which slides to rotate on the cam pin 361 is provided on the outer periphery of the cam pin 361 in such a way that the roller 362 can slide in a recessed groove 232.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for injection molding. 2. Description of the Related Art Conventionally, a slide core is generally used as an injection molding die used for molding a molded article having a hollow portion that becomes an undercut, and a part of the slide core is used. There is known a molded product which forms a hollow portion which serves as an undercut of a molded product. [0003] The above-mentioned slide core usually moves the slide core with the opening and closing of a mold by using an angular pin or an angular cam plate as a guide, so that the slide core is detached from the cavity (Junichiro Shiraishi, "Junichiro Shiraishi"). Injection Mold ", published by Nikkan Kogyo Shimbun. [0004] However, in a conventional injection molding die using a slide core, for example, when the mold opening amount is 100 mm, the length that the slide core can move is limited by an angular pin. 50mm when using
Hereinafter, even when an angular cam plate was used, the limit was 80 mm. [0005] The cause of these problems is that when an attempt is made to increase the amount of movement of the slide core, when an angular pin is used, the sliding resistance between the angular pin and the inclined hole serving as a guide for the angular pin increases, and molding is performed. While repeating, the angular pin may break, and even if the angular cam plate is used, breakage of the angular cam plate or cam pin,
This is because abrasion of the cam groove occurs. SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and reduces the breakage of the angular cam plate and the cam pin, the wear of the cam groove, and the like even in a mold using a slide core, and thus increases the amount of movement of the slide core. It is an object of the present invention to provide an injection molding die that is easy to use. [0007] The injection mold of the present invention comprises a fixed mold and a movable mold, and is provided between the fixed mold and the movable mold when the mold is closed. A cavity corresponding to the shape of the molded article to be molded is provided, and the cavity is an injection molding mold in which a hollow portion serving as an undercut is formed, and one mold is provided with an angular cam plate. And
An angular cam plate (hereinafter sometimes simply referred to as a "cam plate") is provided with a cam groove penetrating the cam plate, and the outer periphery of the cam groove is formed as a concave groove not penetrating the cam plate. The mold is provided with a slide core for forming the hollow portion serving as the undercut, and the slide core is provided with a cam pin passing through the cam groove so as to be movable along the cam groove. On the outer circumference of
A roller that is slidable with respect to the cam pin is provided slidably with the concave groove of the cam plate. In the present invention, the material of the cam plate is not particularly limited, but hardened steel, pre-hardened steel or nitrogen-treated pre-hardened steel or hardened steel is preferable in order to prevent abrasion of the cam groove. In the present invention, the material of the roller is not particularly limited. However, in consideration of the slidability with the concave groove of the cam plate, non-ferrous metals such as copper alloys such as copper, bronze, and brass are considered. Is preferred. (Effect) In the injection mold of the present invention, a hollow portion serving as an undercut is formed in the cavity, and the cavity is formed along the cam groove of the angular cam plate provided in one mold. The cam pin of the slide core provided on the other mold is movable, and a concave groove that does not penetrate the cam plate is provided on the outer periphery of the cam groove.
Since the cam pin and the roller that is slidable and slidable are provided so as to be slidable with the concave groove of the cam plate, even if the movement amount of the slide core is long, breakage of the angular cam plate or the cam pin, breakage of the cam groove, etc. Wear can be reduced. Embodiments of the present invention will be described below in more detail with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a closed state of an injection mold according to the present invention. In FIG. 1, 1 is an injection mold, 2 is a fixed mold, 3 is a movable mold, 4 is a cavity, 23 is an angular cam plate, 231 is a cam groove, 232
Is a concave groove, 36 is a slide core, 361 is a cam pin, 36
2 is a roller. The injection mold 1 according to the present invention comprises a fixed mold 2 and a movable mold 3. The fixed mold 2 includes a fixed mounting plate 21 (made of S55C) and a fixed mold plate 22 (made of S55C). Movable mold 3
Are movable plate 31 (made of S55C), ejector plates 32 and 32 (made of S55C), spacer block 3
3 (manufactured by S55C), a receiving plate 34 (manufactured by S55C), and a movable mold plate 35 (manufactured by S55C). Between the fixed mold plate 22 of the fixed mold 2 and the movable mold plate 35 of the movable mold 3, a cavity 4 corresponding to the shape of a molded product to be molded is provided. It is formed when the mold 2 and the movable mold 3 are closed. Then, a hollow portion (not shown) serving as an undercut is formed in the cavity 4. The fixed die 2 is provided with an angular cam plate 23, and the angular cam plate 23 is provided with a cam groove 231 passing through the cam plate 23.
The outer periphery of 31 is formed as a concave groove 232 that does not penetrate the cam plate 23. The angular cam plate 23 is made of SKD11 whose surface is nitrided (Rockwell hardness HRc60).
The wear of the cam groove 231 is reduced. The movable core 3 has a slide core 36 (SUS6) for forming the undercut hollow portion.
30 is provided, and the slide core 36 is provided with a cam pin 361 (manufactured by SKH51) that passes through the cam groove 231 so as to be movable along the cam groove 231. A roller 362 (made of copper brass: C3604) slidable and slidable on the cam 361 is provided slidably with the concave groove 232 of the cam plate 23. In order to obtain a molded product using the injection mold 1 according to the present invention, a molten thermoplastic resin is injected into the cavity 4 from an injection molding machine (not shown). Next, after the injected thermoplastic resin is solidified, the fixed mold 2 and the movable mold 3 are opened as shown in FIG. When the fixed mold 2 and the movable mold 3 are opened, the cam pin 361 moves along the cam groove 231,
The roller 362 moves while sliding along the concave groove 232 of the cam plate 23. Then, as the cam pin 361 moves, the slide core 36 comes out of the molded product 5 filled in the cavity 4. Then, the molded product 5 is released from the movable mold plate 35 by ejecting the ejector pins 37. The mold for injection molding of the present invention is constructed as described above. Therefore, even in a mold using a slide core, breakage of the angular cam plate or the cam pin, wear of the cam groove, etc. Therefore, it is easy to increase the amount of movement of the slide core.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing an example of an injection mold according to the present invention, showing a state in which the mold is clamped. FIG. 2 is a cross-sectional view showing one example of an injection mold according to the present invention, showing a state where the mold is opened. [Description of Signs] 1 Injection molding mold 2 Fixed mold 3 Movable mold 4 Cavity 5 Molded product 23 Angular cam plate 231 Cam groove 232 Concave groove 36 Slide core 361 Cam pin 362 Roller

Claims (1)

Claims: 1. A fixed-side mold and a movable-side mold, which correspond to the shape of a molded product to be molded between the fixed-side mold and the movable-side mold at the time of closing. A cavity is provided, and the cavity is an injection molding mold in which a hollow portion serving as an undercut is formed. One of the molds is provided with an angular cam plate, and the angular cam plate passes through the cam plate. And the outer periphery of the cam groove is formed as a concave groove that does not penetrate the cam plate, and the other mold is provided with a slide core for forming the hollow portion serving as the undercut, The slide core is provided with a cam pin that passes through the cam groove, and is movable along the cam groove.On the outer periphery of the cam pin, a roller that can rotate and slide with the cam pin is provided with a concave groove of the cam plate. Slidably provided Injection mold characterized by and.