JPH0452025Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to an injection molding machine used to fill a mold cavity with a molten resin such as a thermosetting resin or a thermoplastic resin. This invention relates to an injection molding machine equipped with a shaft-shaped valve body that can open and close a resin flow path in a nozzle at the tip.

[Prior art] For example, in an injection molding machine for thermosetting resin,
There are two methods of measuring the resin necessary for injecting into the mold by rotating the screw in the molding machine a certain number of times: the nozzle touch measuring method, which measures the resin with the nozzle in contact with the resin filling port of the mold, and the There is a nozzle release method, which measures with the nozzle released. In the case of the nozzle touch metering method, the heat retained in the nozzle is taken away by the mold, the nozzle is cooled, and the resin inside the nozzle hardens, so the nozzle release metering method is generally used. However, in the nozzle release metering method, if the resin flow path of the nozzle remains open, a so-called drawling phenomenon occurs in which the molten resin inside the molding machine drips from the nozzle tip due to the conveying pressure caused by the rotation of the screw during metering.

To prevent the drawling phenomenon, conventionally, a needle valve is placed in the center of the nozzle with a spring biasing it in the closing direction, and during injection, the injection pressure forces the needle valve to retreat against the spring. Generally, an injection molding machine is used in which the resin flow path of the nozzle is opened.

In addition, an injection molding machine equipped with a belt-shaped shutter at the tip of a nozzle is known, as described in Japanese Patent Application Laid-Open No. 57-31545.

[Problem to be solved by the invention] In the conventional injection molding machine equipped with the above-mentioned needle valve, the opening/closing timing of the needle valve is determined by the spring force that biases the needle valve in the closing direction and the injection pressure of the resin. Therefore, adjusting the spring force is delicate and requires skill, and the heating to melt the resin can make the characteristics of the spring unstable and change the biasing force, which can cause the opening/closing timing of the needle valve to be out of order. Sometimes.

Furthermore, in the injection molding machine described in the above publication, the drive device for the strip shutter is installed outside the molding machine, and sensors and controllers are required to control the drive device, making the structure complicated and manufacturing difficult. There are problems such as high cost.

This idea was created in view of the above points, and the molten resin flow path inside the nozzle can be opened and closed reliably without using an external drive device, and there is no need for a special device to control the timing of opening and closing. The purpose is to provide an injection molding machine that has a simple structure and can be manufactured at low cost.

[Means for Solving the Problems] In order to achieve the above object, the injection molding machine of this invention has a shaft-shaped valve body installed in the nozzle at the tip of the injection molding machine, orthogonally to the resin flow path in the nozzle. is rotatably arranged, and a through hole is provided in the valve body to communicate with the flow passage at a specific rotational position,
A rotation control lever of the valve body is attached to a portion of the valve body that protrudes outward from the nozzle, and the through hole communicates with the flow path at a position where the nozzle of the injection molding machine contacts the resin filling port of the mold, a set of abutments that abut the operating lever and rotate the valve body so that the through hole does not communicate with the flow path at a position where the nozzle of the injection molding machine is a predetermined distance from the resin filling port of the mold; We have established a department.

Further, as described in claim 2, a shaft-shaped valve body is rotatably disposed in the nozzle at the tip of the injection molding machine so as to be perpendicular to the resin flow path in the nozzle, and the valve body includes: A through hole that communicates with the flow path is opened at a specific rotational position, and a rotation operating lever of the valve body is attached to a portion of the valve body that protrudes outward from the nozzle, and the valve body is The control lever is biased by a biasing means to a rotational position that does not communicate with the flow path, and the through hole is in contact with the flow path at a position where the nozzle of the injection molding machine contacts the resin filling port of the mold. A contact portion may be provided that contacts the valve body and rotates the valve body against the biasing means.

Further, it is preferable that the operating lever is attached to the valve body so that its attachment position can be adjusted.

[Function] According to the injection molding machine of this invention having the above-described configuration, when the injection molding machine is located at a certain distance from the mold, the operating lever of the shaft-shaped valve body is located at one of the abutting portions. The valve body rotates to a specific rotational position and closes the resin flow path within the nozzle. In this state, resin is supplied into the injection molding machine, a measuring operation is performed, and a predetermined amount of resin is stored. Therefore, the resin does not drip from the nozzle tip when measuring the resin. Next, when the injection molding machine is brought relatively close to the mold, just before the tip of the nozzle contacts the filling port of the mold, the operating lever contacts the other contact part and the valve body rotates. The through hole communicates with a resin flow path within the nozzle. In other words, the resin flow path within the nozzle is opened. Then, with the tip of the nozzle in contact with the filling port,
Molten resin, which has been measured and stored in advance in the injection molding machine, is injected from the nozzle tip and filled into the mold.

After filling the molten resin into the mold in this way, when the injection molding machine is relatively separated from the mold, the control lever of the valve body is moved to the contact portion by the time the two are separated by a predetermined distance. The valve body rotates as it comes into contact with the nozzle, closing the resin flow path in the nozzle.

According to the injection molding machine according to the second aspect of the present invention, the valve body closes the resin flow path in the nozzle by the urging means at the same time that the tip of the nozzle leaves the resin filling port of the mold.

Furthermore, according to the injection molding machine according to claim 3, when changing the mold, the mounting position of the operating lever with respect to the valve body can be changed appropriately according to the installation location and shape of the mold. The flow passage within the nozzle can be opened accurately at the position where the nozzle tip touches the filling port of the mold.

[Example] Hereinafter, an example of the injection molding machine of this invention will be described based on the drawings.

Fig. 1 is a vertical cross-sectional view showing the overall outline of the injection molding machine according to the embodiment, and Fig. 2 shows the opening state of the valve body, where a is a plan view, b is a longitudinal cross-sectional view, and 3 shows the valve body in a closed state, FIG. 3A is a plan view, FIG.

In FIG. 1, 1 is an injection molding machine that uses a resin material such as a thermosetting resin. It is configured to move forward and backward with respect to the mold 12 (see FIG. 2). A screw 3 is loaded into the cylindrical housing 1a of the injection molding machine 1 so as to be able to rotate and move back and forth, and a drive device 10 for rotating and moving the screw 3 is installed at the base end of the screw 3. A hopper 4 is disposed on the upper surface of the proximal side of the housing 1a.
Chip-shaped resin is supplied onto the screw 3 within the housing 1a. A heating device (not shown) is provided in the housing 1a to heat and melt the resin in the housing 1a.

An injection nozzle 5 is connected to the tip of the housing 1a, and a molten resin flow path 1 inside the housing 1a is connected.
b and a molten resin flow path 5a in the nozzle 5 are communicated with each other. A shaft-shaped valve body 6 made of a cylindrical body is rotatably interposed in the middle of the molten resin flow path 5a (preferably at a position close to the tip opening 5b) so as to be perpendicular to the flow path 5a. As shown in FIG. 4, in order to interpose this shaft-shaped valve body 6,
A vertical fitting hole 7 is bored in the nozzle 5 . Then, by fitting the valve body 6 into the insertion hole 7, and tightening the nut 6c by screwing it into the threaded part 6b at the lower end with the large diameter part 6a at the upper part in contact with the upper surface of the nozzle 5, A valve body 6 is rotatably inserted into the insertion hole 7. The valve body 6 also has a through hole 6 that can communicate with the flow path 5a at a specific rotational position.
d is bored horizontally, and by rotating the valve body 6, the flow passage 5a can be closed or opened. Furthermore, the large diameter portion 6a of the valve body 6
An operating lever 8 for rotating this is attached to. Although not particularly limited, as shown in FIG. 4, a threaded rod 9 is provided protruding from the large diameter portion 6a in parallel with the through hole 6d, and the threaded rod 9 is inserted through the insertion hole 8a opened in the operating lever 8. By sandwiching and fixing the lever 8 with a pair of nuts 9a screwed onto the threaded rod 9, the mounting position of the operating lever 8 relative to the valve body 6 can be adjusted as appropriate. Code 8b in Figure 4
8c is a locking plate for preventing rotation, and 8c is a contact portion 1 to be described later.
1 (see FIG. 3a).

In addition, as shown in Figures 2a and 3a,
Near the standby position of the injection molding machine 1, a contact portion 11 for rotating the valve body 6 to the closed position is provided so as to be able to come into contact with the operating lever 8. In this embodiment, the front wall 12a of the mold 12 is used as the other contact portion for rotating the valve body 6 to the open position.

Next, the operation of the above embodiment will be explained.

In FIG. 1, from the hopper 4 to the housing 1
The chip-shaped resin supplied into the screw 3
fall on top. As the screw 3 rotates, the resin is sent toward the distal end and is melted by the rotational force of the screw 3 and a heating device (not shown) in the housing 1a. At this time, the amount of resin required for injection molding is measured by the rotation speed of the screw 3,
The molten resin is stored near the tip of the screw 3 in the housing 1a and the flow passages 1b and 5a in the nozzle 5. During such metering operation, the valve body 6
is in a specific rotational position as shown in FIG. 3, and the flow passage 5a of the nozzle 5 is closed.

Thereafter, the injection molding machine 1 is advanced by the reciprocating device 2 toward the mold 12 (FIG. 2). and,
As shown in FIG. 2, the operating lever 8 of the valve body 6 comes into contact with the front wall 12a of the mold 12, the valve body 6 rotates, and the through hole 6d becomes in communication with the flow path 5a of the nozzle 5. Almost simultaneously, the tip opening 5b of the nozzle 5 comes into contact with the filling port 12b of the mold 12. In this state, the screw 3 in the injection molding machine 1 moves forward to extrude the molten resin and fills it into the cavity (not shown) of the mold 12 through the filling port 12b.

After the filling of the molten resin is completed, the injection molding machine 1 is moved back to the original standby position by the reciprocating device 2 as shown in Fig. 3. Just before this, the operating lever 8 of the valve body 6 comes into contact with an abutment portion 11 provided near the standby position of the injection molding machine 1, causing the valve body 6 to rotate, and the flow passage 5a in the nozzle 5 is closed.

Incidentally, in the above embodiment, the operating lever 8 of the valve body 6 is brought into contact with the front wall 12a of the mold 12 to open the flow passage 5a. Instead of using it as a contact part, a separate operating member may be provided on the fixed die plate or the like. Further, although the shaft-shaped valve body 6 is fitted in the vertical direction of the nozzle 5, it may be fitted in the nozzle 5 in the horizontal direction so as to be perpendicular to the flow path 5a.
Further, although the injection molding machine 1 is moved forward and backward relative to the mold 12, even if the mold 12 is moved forward and backward relative to the injection molding machine 1, the installation position of the contact portion 11, etc. may be changed. It can be implemented similarly by

Next, FIG. 5 shows another embodiment of this invention.
3a is a plan view corresponding to FIG. 3a; FIG.

In the injection molding machine 1' of this embodiment, the valve body 6 is biased in the closing direction by a spring 14 as a biasing means to close the flow passage 5a in the nozzle 5 in the normal state, but unlike the above embodiment, the injection molding machine 1' This is different from injection molding machine 1. That is, a support member 15 for a spring 14 is fixed at a proper position of the nozzle 5, and the spring 14 is compressed and interposed between the support member 15 and the operating lever 8. Therefore, the contact portion 11 for rotating the valve body 6 in the closing direction is no longer necessary. Further, the valve body 6 is rotated by the biasing force of the spring 14 at the same time that the tip opening 5b of the nozzle 5 separates from the filling port 12b of the mold 12, so the flow path 5a closes at the moment the nozzle 5 separates from the filling port 12b. It started to be done. Note that the operation lever 8 of the valve body 6 contacts the front wall 12a of the mold 12 to open the valve body 6, which is the same as in the above embodiment.

[Effects of the invention] As is clear from the above explanation, the injection molding machine of this invention has the following effects.

(1) The shaft-shaped valve body for opening and closing the resin flow passage in the nozzle can be operated without using an external drive device, and there is no need for a control device to control the timing of opening and closing. can be manufactured very easily and inexpensively. Furthermore, since the opening and closing operations of the valve body are performed without using a delicate control device, the opening and closing operations are stable over a long period of time. Furthermore, when measuring resin in an injection molding machine, the valve body reliably closes the flow path in the nozzle, so there is no risk of a drawling phenomenon occurring. moreover,
Since the valve body can be placed in the flow path close to the tip opening of the nozzle, the flow path between the tip opening and the valve body is almost never clogged with resin, and even if resin does become clogged, , can be easily removed.

(2) In addition to the above-mentioned effects, the injection molding machine according to claim 2 has the effect that resin leakage can be more reliably prevented since the flow passage is closed by the valve body at the same time as the nozzle leaves the mold. be.

(3) The injection molding machine according to claim 3 is convenient because the mounting position of the operating lever of the valve body can be changed as appropriate depending on the shape of the mold, etc., and the timing of opening and closing of the valve body can be delicately adjusted. This allows the flow path within the nozzle to be opened and closed accurately.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the overall outline of the injection molding machine according to the embodiment, FIG. 2 is a diagram showing the opening state of the valve body, and FIG. Figure b is a longitudinal sectional view of the same, Figure 3 shows the closed state of the valve body, Figure a is a partial plan view of the injection molding machine and the mold, Figure b is a longitudinal sectional view of the same, and Figure 4 is a longitudinal sectional view of the same. The figure is an enlarged perspective view showing an exploded state of the valve body. FIG. 5 is a plan view corresponding to FIG. 3a, showing another embodiment of this invention. 1, 1'...Injection molding machine, 2...Reciprocating device,
3... Screw, 5... Nozzle, 5a... Resin flow path, 6... Shaft-shaped valve body, 6d... Through hole, 8... Operation lever, 11... Contact portion, 12...
...Mold, 12a...Front wall (contact part), 14...
spring.

Claims (1)

[Claims for Utility Model Registration] 1. A shaft-shaped valve body is rotatably disposed in the nozzle at the tip of the injection molding machine so as to be orthogonal to the resin flow path in the nozzle, and a specific A through hole communicating with the flow path is opened at a rotational position of the valve body, a rotation control lever of the valve body is attached to a portion of the valve body that protrudes outward from the nozzle, and the nozzle of the injection molding machine is configured to fill the mold with resin. The through hole communicates with the flow path at a position in contact with the mouth,
a set of abutments that abut the operating lever and rotate the valve body so that the through hole does not communicate with the flow path at a position where the nozzle of the injection molding machine is a predetermined distance from the resin filling port of the mold; An injection molding machine characterized by having a section. 2. A shaft-shaped valve body is rotatably disposed in the nozzle at the tip of the injection molding machine so as to be orthogonal to the resin flow path in the nozzle, and the valve body is connected to the flow path at a specific rotational position. A communicating through hole is provided, a rotation control lever for the valve body is attached to a portion of the valve body that protrudes outward from the nozzle, and the valve body is placed in a rotational position where the through hole does not communicate with the flow path. The valve body is urged by the urging means, and the valve body is brought into contact with the operating lever so that the through hole communicates with the flow path at a position where the nozzle of the injection molding machine contacts the resin filling port of the mold. An injection molding machine characterized by being provided with a contact part that rotates against. 3. The injection molding machine according to claim 1 or 2, wherein the operating lever is attached to the valve body so that its attachment position can be adjusted.