JP3527564B2 - Injection molding machine for molded products with screw part - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a male screw or a female screw formed integrally with a device such as a knob or a handle used by being screwed to a shaft of an apparatus. The present invention relates to an injection molding machine for molded articles. 2. Description of the Related Art Conventionally, when performing injection molding of a molded product having a threaded portion, an insert having an internal thread formed therein is manufactured in advance, and one mold of an injection molding machine is manufactured. A guide pin protrudes into the cavity of the mold, and the guide pin protrudes toward the cavity of the other mold, and a medium crack groove is formed at the tip of the guide pin along the length direction. In addition, there is one that facilitates mounting of an insert fitting (Japanese Utility Model Application Laid-Open No. Sho 62-173912). According to this, an insert fitting is attached to the tip of the guide pin with the fixed mold and the movable mold open, and both the fixed mold and the movable mold are inserted with the insert mold inserted into the cavity. Close and injection mold. When the movable mold is opened after the molded product has hardened, the insert fitting is detached from the tip of the guide pin while being embedded in the product, and the product is pushed out by the ejector pin. [0003] However, in the conventional example, it is necessary to manufacture an insert having a female screw portion separately from a molded product in advance, and furthermore, the insert has a Since a relatively long cooling time is required to be firmly embedded in the molded article, it has been difficult to quickly mold the molded article. Accordingly, an object of the present invention is to form a molded product having a threaded portion by forming the threaded portion integrally with the molded product, shortening the cooling time, and rapidly molding the molded product. It is an object of the present invention to provide a possible injection molding machine. A feature of the present invention is that a thread forming member is provided in a movable mold so as to be slidable and rotatable in the front-rear direction, and a tip of the thread forming member is provided at the tip of the thread forming member. The thread is
A connection portion is formed at the rear end, the screw forming member can advance toward the cavity by the movable driving body and the screw portion can enter the cavity, and the connection portion is connected to the rotary drive shaft. interlocking rotatably and slidably fitted in the axial direction, further, the connecting portion is Yes and interposed into the accommodation hole is formed to the movable drive member, in this accommodating hole provided spring The spring urges the connecting portion in an anti-cavity direction. An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, an injection molding machine for a molded article having a threaded portion according to the present invention comprises a fixed mold A and a movable mold B, and the fixed mold is a fixed mold. Side template 1
Are fixedly mounted on the mounting plate 11 on the fixed side. The central portion of the stationary-side mold plate 1 and the stationary-side mounting receiving plate 11, Yes and sprue bushing 12 is inserted, the sprue bush is fixed by a locating ring 13.
The sprue bush 12 communicates with the sprue runner 14. The structure of the movable mold B is such that the movable mold plate 2 is mounted on a movable mounting plate 23 via a spacer block 21 and a block 22, and the whole is integrated. The fixed-side mold plate 1 and the movable-side mold plate 2 are in contact with each other, and cavities 3 are formed in opposing surfaces at positions facing each other. And sprue runner 14
Communicate with the cavity 3 through the gate. A guide pin bush 15 is inserted near the outer periphery of the fixed mold plate 1, and a guide pin 24 is attached near the outer periphery of the movable mold plate 2.
This guide pin is guided by the guide pin bush when the movable mold B is moved. A receiving portion 21a protrudes inside the spacer block 21, and an ejector plate 6 is located above (in front of) the receiving portion 21a in a hollow portion in the spacer block. A sprue lock pin 62 projects from the center of the upper surface of the ejector plate 6 toward the upper sprue runner 14. The ejector plate 6 has an ejector pin 63 projecting upward in parallel with the sprue lock pin 62 at a predetermined interval. The sprue lock pin 62 and the ejector pin 63 are movably inserted in the movable mold plate 2, and
2 can enter the sprue runner 14,
The tip of the ejector pin 63 can enter the cavity 3. The movable driver 5 is provided in a hollow portion of the spacer block 21, and is located below (rearward) the receiving portion 21a. A through hole 53 is formed in the center of the movable driving body 5, and a first ejector rod 61 is formed in the through hole.
Is movably inserted, and the upper end of the first ejector rod is connected and fixed to the center of the ejector plate 6. A second ejector rod 51 in the form of a coaxial pipe is loosely fitted around the outer periphery of the first ejector rod 61, and the second ejector rod and the first ejector rod are movable independently of each other. A drive cylinder (not fixed) is provided at the rear end of each rod. The upper end of the second ejector rod 51 is fixed to the central part of the movable driving body 5. The movable driving body 5 is formed by combining two plates, and a storage hole 5a is formed therein so as to be long in the vertical direction. The screw forming pin 4 has a screw portion 41 at its upper end.
However, a connecting portion 42 is formed at the lower end, and penetrates the movable driving body 5, the ejector plate 6, and the movable side mold plate 2, respectively. The screw portion 41 is for forming a female screw portion in a molded product. And can enter the cavity 3. The connecting portion 42 has a cylindrical shape with a rear end opening, has a square inner wall surface, and is inserted into the storage hole 5a. The outer diameter of the connecting portion 42 is slightly larger than the diameter of the shaft portion of the screw forming pin 4, but slightly smaller than the inner diameter of the storage hole 5a. For this reason, the connecting portion 42 is rotatable in the storage hole 5a and slidable in the vertical direction. A spring 52 is wound around the shaft of the screw forming pin 4 in the housing hole 5a. That is, the spring 52 is located between the upper surface of the storage hole 5a and the connecting portion 42, and when pressed by the connecting portion, elastically moves the connecting portion in the direction opposite to the cavity 3 (downward). Force can be energized. Since the upper end of the prismatic rotary drive shaft 7 is inserted into the square insertion hole of the connecting portion 42, the connecting portion can be rotated in conjunction with the rotary drive shaft, but in the axial direction of the rotary drive shaft. Are slidably fitted. The rotary drive shaft 7 is rotatably supported by a ball bearing 22a in a block 22. A worm wheel 71 is mounted on the outer periphery of the rotary drive shaft. The worm wheel 71 is rotatably positioned in a hole 22b formed in the block 22, and a worm 72 meshes with the worm wheel. The worm is driven to rotate by a motor M. Next, the operation of the present invention will be described. In order to form a molded product, first, as shown in FIG. 1, a fixed mold plate 1 and a movable mold plate 2 are brought into contact with each other in a mold-clamped state. At this time, the lower surface of the ejector plate 6 is in contact with the receiving portion 21 a of the spacer block 21, and the lower surface of the movable driver 5 is in contact with the block 22. For this reason, the ejector pin 63
And the screw part 41 does not enter the cavity 3.
The sprue lock pin 62 is connected to the sprue runner 14.
Has not entered. Next, as shown in FIG. 2, the second ejector rod 51 is advanced, and the upper surface of the movable driving body 5 is
Move forward until it contacts 1a. Since the screw forming pin 4 also advances with the advance of the movable driving body 5, the screw portion 41 enters the cavity 3. Then, in this state, when synthetic resin is injected and injected from an injection nozzle (not shown) in contact with the sprue bush 12, the resin is injected into the cavity 3 from the gate through the sprue runner 14. When the resin in the cavity 3 is solidified and a molded product is formed, the second ejector rod 51 is retracted as shown in FIG. 3, and is retracted until the lower surface of the movable driver 5 contacts the block 22 again. Let it. At this time, the storage hole 5a
The spring 52 provided therein is pressed by the connecting portion 42 of the screw forming pin 4 and the upper surface of the storage hole 5a. However, since the spring spring 52 has a weak spring force, the screw portion 41 of the screw forming pin 4 does not fall out of the molded product. Then, in order to separate the screw portion 41 from the molded product, the motor M is driven to rotate the worm 72, and the rotary drive shaft 7 is rotated via the worm wheel 71. For this reason, the screw forming pin 4 simultaneously rotates in conjunction with the rotation drive shaft 7, and the screw portion 41 starts to separate from the molded product by a spiral motion along the screw groove. At the moment when the screw portion 41 separates from the molded product, the elastic force of the spring 52, which has been compressed, causes
The connecting portion 42 is extruded in the direction opposite to the cavity 3,
Since this connecting portion slides in the axial direction of the rotary drive shaft 7, the screw portion 41 easily separates from the molded product. Finally, as shown in FIG.
Is moved to separate the mold from the fixed mold plate 1 to open the mold. Then, by the advance of the first ejector rod 61,
The ejector plate 6 is advanced until the upper end surface of the ejector plate 6 comes into contact with the movable mold plate 2. With the advance of the ejector plate, the ejector pin 63 and the sprue lock pin 62 advance, and the ejector pin 63 protrudes the molded product, and The lock pin 62 protrudes the residue in the sprue runner adhering to the molded product. The means for driving the rotary drive shaft is not limited to the means described above. The worm may mesh with a plurality of worm wheels. When it is desired to form a male screw portion on a molded product,
What is necessary is just to form a screw part into a female screw. According to the present invention, when molding a molded product having a threaded portion, the threaded portion can be formed integrally with the molded product, and it is necessary to separately mold the insert fitting in advance. Therefore, a molded article can be formed without any labor and cost. Furthermore, since the time required to cool the molded article can be shortened, the molded article can be molded quickly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a state in which a mold is clamped. FIG. 2 is a cross-sectional view showing a state where a resin is being injected. FIG. 3 is a cross-sectional view showing a state where a movable driving body is retracted. FIG. 4 is a sectional view showing a state in which the mold is opened. [Description of Signs] 1 Fixed-side mold plate 2 Movable-side mold plate 3 Cavity 4 Screw forming member (screw forming pin) 41 Screw portion 42 Connecting portion 5 Movable driving body 51 Storage hole 52 Spring spring 6 Ejector plate 62 Sprue lock pin 63 Ejector pin 7 Rotation drive shaft

Claims (1)

(57) [Claims 1] A fixed-side mold and a movable-side mold, and a cavity is formed by the fixed-side mold plate and the movable-side mold plate of both molds. An injection molding machine in which ejector pins are provided inside and outside so as to be able to move forward and backward, wherein a screw forming member (4) is provided slidably in the front-rear direction and rotatable in the movable mold. A threaded portion (41) is formed at the front end of the formed member, and a connecting portion (42) is formed at the rear end thereof. The screw formed member can advance toward the cavity by the movable driving body (5), And the screw portion is capable of entering the cavity, the coupling portion is interlockably rotatable with the rotary drive shaft (7) and is slidably fitted in the axial direction, and the coupling portion is fitted to the movable driving body. In the formed storage hole
A spring (52) is provided in the storage hole.
This spring causes the connecting portion to repel in the direction opposite to the cavity.
Injection molding machine molded article having a threaded portion, characterized in that biasing the sexual force.