JPH028568B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ejector rod drive device for an injection molding machine equipped with an ejector cylinder that drives an ejector plate and a mold clamping cylinder that drives a mold. This invention relates to an ejector rod drive device whose structure can be simplified by eliminating the hydraulic switching valve for controlling the ejector cylinder.

Conventionally, as an ejector device for ejecting a molded product, the one shown in FIG. 1 is known.

In the figure, an ejector plate 4 is provided in a lower space 3 of a lower mold 2 mounted on a mold plate 1 so as to be movable up and down, and an ejector pin 5 is mounted on the ejector plate 4. It is installed protrudingly.

A mold clamping cylinder 6 is provided below the mold plate 1, and its piston rod 7 is connected to the mold plate 1. An ejector cylinder 8 is formed within the piston rod 7, and an ejector rod 9 is housed therein. The ejector rod 9 slidably passes through the mold plate 1 and is brought into contact with the lower part of the ejector plate 4. In addition, 10
is the upper type.

During the mold clamping operation, the mold clamping cylinder 6 is operated by hydraulic oil from the mold clamping oil hole 11, and the piston rod 7 moves forward to raise the mold plate 1 and clamp the lower mold 2 and the upper mold 10. .

During the mold opening operation, the piston rod 7 is lowered by hydraulic oil from the mold opening oil hole 12 to open the mold.

When ejecting the molded product M, the ejector rod 9 of the ejector cylinder 8 is moved forward by the hydraulic oil from the hydraulic oil hole 13.
The ejector plate 4 is raised and the ejector pin 5 is projected upward, thereby ejecting the molded product M.

As a drive device for the ejector rod in such a configuration, the one shown in FIG. 2 is known.

When clamping the mold, the hydraulic oil from the hydraulic source 5 is
As shown by the solid arrow, it flows through the mold clamping line 17 through the mold clamping passage 16a of the bistable mold operation switching valve 16, flows into the rear chamber 6b of the mold clamping cylinder 6, and advances the piston rod 7. .

At this time, the hydraulic oil in the front chamber 6a of the mold clamping cylinder 6 flows out into the mold opening pipe 18 and is discharged into the tank 19 via the mold clamping path 16a.

The mold clamping operation is detected by the mold clamping end position sensor 20, and the mold operation control timer 21 starts a timing operation. During the timing operation, the mold is kept in a clamped state, and during this time, the injection, pressure holding, and cooling steps are performed.

Next, the switching valve 16 is switched from the mold closing path 16a to the neutral path 16b to the mold opening path 16c in response to the timing operation end signal of the timer 21.

Then, the hydraulic oil from the hydraulic source 15 flows into the mold opening line 18 as shown by the dotted arrow, flows into the front chamber 6a of the mold clamping cylinder 6, and causes the piston rod 7 to retreat.

At this time, the hydraulic oil in the rear chamber 6b is transferred to the mold clamping pipe 1.
7 and is discharged into a tank 19 via a switching valve 16.

The mold opening operation is detected by the mold opening end position sensor 22, and the edging operation control timer 23 starts a timing operation. In response to the timing operation signal of the timer 23, the switching valve 16 is switched from the mold opening path 16c to the neutral path 16b.

On the other hand, at the same time, the monostable edge excision switching valve 24 is switched to the protruding path 24b, and is held in the protruding path 24b while the timer 23 is operating.

As a result, the hydraulic oil from the hydraulic source 15 flows into the protruding pipe 25 as shown by the dashed line arrow, and after being speed-adjusted by the flow rate adjustment valve 26, the hydraulic oil flows into the rear chamber 8b of the ejector cylinder 8. and causes the ejector rod 9 to protrude forward.

At this time, the hydraulic oil in the front chamber 8a of the cylinder 8 flows out into the return pipe 27 and is discharged into the tank 19 through the protruding path 24b of the switching valve 24.

When the timing operation of the timer 23 is completed, the timing operation signal also disappears, the switching valve 24 is automatically switched to the return path 24a, and the hydraulic oil is transferred to the return circuit 27 as shown by the two-dot chain arrow. flows into the front chamber 8a of the ejector cylinder 8,
Retract the ejector rod 9. At this time,
The hydraulic oil in the rear chamber 8b flows through the check valve 28 into the protruding pipe 25, and is discharged into the tank 19 through the switching valve 24.

However, in the above-mentioned conventional technology, two solenoid switching valves are required, one for operating the mold and the other for operating the edge extrusion, which complicates the overall structure and reduces operational reliability. However, there was an additional disadvantage of high cost.

An object of the present invention is to incorporate a return spring inside the ejector cylinder to return the ejector rod, in view of the problems such as the complicated structure due to the structural limitations of the ejector rod drive device based on the above-mentioned prior art. By configuring the hydraulic oil pipe of the ejector cylinder to be connected to the mold opening pipe of the mold clamping cylinder, the above-mentioned drawbacks and disadvantages are eliminated, and the structure is simple and the operation reliability is high. It is an object of the present invention to provide an excellent ejector rod drive device.

In accordance with the above object, the structure of the present invention is such that the ejector rod is always biased in the backward direction, is not operated by the exhaust pressure from the mold clamping cylinder during the mold clamping operation, and furthermore, the ejector rod is not activated by the exhaust pressure from the mold clamping cylinder during the mold closing operation. The ejector rod does not operate even with the hydraulic pressure applied to the mold clamping cylinder, and the ejector rod The gist of the present invention is to make it possible to automatically project the ejector rod and to automatically return the ejector rod in accordance with the return from the mold opening operation.

Next, an embodiment of the present invention will be described below based on the drawings from FIG. 3 onwards.

As shown in FIG. 3, a return spring 30 is installed inside the ejector cylinder 8 to constantly bias the ejector rod 9 in the backward direction. The spring 30
has a spring constant such that it is not compressed by the exhaust pressure from the mold clamping cylinder 6 that occurs during the mold clamping operation or by the mold opening hydraulic pressure in the mold clamping cylinder 6 that occurs during the mold opening operation.

As shown in FIG. 4 and below, the hydraulic oil pipe 31 of the ejector cylinder 8 is connected to the mold opening pipe 1 which connects the mold clamping cylinder 6 and the mold operation switching valve 16.
8 is connected.

Note that the other components are the same as those indicated by the same reference numerals in FIGS. 1 and 2.

In the above configuration, during mold clamping work, as shown in FIG. 4, when the mold operation switching valve 16 is switched to the mold clamping path 16a, the hydraulic oil from the hydraulic source 15 passes through the path 16a to the mold clamping pipe. Flows to 17,
It flows into the rear chamber 6b of the mold clamping cylinder 6, moves the piston rod 7 forward, and clamps the mold. At this time, the hydraulic oil in the front chamber 6a of the mold clamping cylinder 6 flows out into the mold opening pipe 18 and is discharged into the tank 19 via the path 16a.

During this time, the ejector cylinder 8 is subjected to the exhaust oil pressure flowing through the mold opening line 18 via the hydraulic oil line 31, but since this oil pressure is extremely low, the ejector rod 9 operates against the return spring 30. Never.

When the mold clamping operation is completed, as shown in FIG. 5, the mold clamping end position sensor 20 detects this, and the mold operation control timer 21 starts a timing operation. During the time measurement operation, the mold is kept in a closed state, and during this time, injection, pressure holding, and cooling steps are performed.

When the timing operation of the timer 21 ends, the mold operation switching valve 16 is switched from the mold closing path 16a to the neutral path 16b to the mold opening path 16c in response to the timing operation end signal. As a result, the hydraulic oil from the hydraulic source 15 flows into the mold opening line 18 through the mold opening path 16c, flows into the front chamber 6a of the mold clamping cylinder 6, and causes the piston rod 7 to retreat.

During this time, the mold opening hydraulic pressure acts on the ejector cylinder 8 via the pipe 31, but the return spring 30 inside the ejector cylinder 8 sufficiently resists the mold opening hydraulic pressure, so that the ejector cylinder 8 is closed. 9 is not projected forward.

Next, as shown in FIG. 6, when the mold opening operation ends, the mold opening end position sensor 22 detects this, and the edge extraction operation control timer 23 starts a timing operation. At the same time, the pressure in the front chamber 6a of the mold clamping cylinder 6 and the mold opening pipe 18 rises because the backward movement of the piston rod 7 is restricted, and the increased hydraulic pressure is transferred to the pipe 31.
It is then introduced into the ejector cylinder 8 via the flow rate regulating valve 26.

The increased hydraulic pressure causes the ejector rod 9 to move forward while compressing the return spring 30. The ejector rod 9
The protruding state is maintained until the timer 23 completes its timing operation.

When the timing operation of the timer 23 is completed, as shown in FIG.
The route is then switched to the neutral route 16b.

Then, the mold opening pipe 18 and the hydraulic oil pipe 31 are connected to the tank 19, so the ejector rod 9 is moved back and returned by the action of the return spring 30, and the hydraulic oil in the ejector cylinder 8 is reversed. It flows out into the hydraulic oil line 31 through the stop valve 28, and is discharged into the tank 19 through the mold opening line 18 and the neutral path 16b of the switching valve 16.

As described above, according to the present invention, the ejector cylinder that drives the ejector plate, the mold clamping cylinder that drives the mold, and the mold clamping cylinder are connected to the mold clamping pipe and the mold opening pipe. In the ejector rod drive device of an injection molding machine, the ejector rod drive device for an injection molding machine includes a mold operation switching valve and a return spring is installed in the ejector cylinder to constantly bias the ejector rod in the backward direction. By connecting the hydraulic oil pipe to the mold opening pipe, the ejector rod does not operate during the mold closing operation and the mold opening operation, and the mold clamping cylinder does not operate when the mold opening is completed. The ejector rod is moved forward by utilizing the rise in hydraulic pressure in the mold opening line, and is automatically returned to its original position by spring pressure after a predetermined period of time has elapsed after the mold opening is completed. Therefore, it is possible to eliminate the conventionally required edging operation switching valve, which has the excellent effect of greatly simplifying the overall structure and improving reliability.

With the abolition of the ejection operation switching valve, only the return spring is added, which has the advantage of significantly reducing costs.

In addition, it is extremely simple because it can be implemented with minimal modifications to the conventional method.

[Brief explanation of drawings]

Figures 1 and 2 show conventional examples;
The figure is a sectional view showing the mold device part, FIG. 2 is an ejector rod drive device, FIG. 3 and the following show embodiments of the present invention, and FIG. Fig. 4 and the following are explanatory diagrams of the operation of the ejector rod drive device, Fig. 4 is an explanatory diagram of the mold clamping operation, Fig. 5 is an explanatory diagram of the mold opening operation, and Fig. 6 is an explanatory diagram of the ejector rod protruding operation. , FIG. 7 is an explanatory diagram of the ejector rod return operation. 1... template, 2... lower mold, 3... lower space, 4
... Ejector plate, 6 ... Mold clamping cylinder, 7 ... Piston rod, 8 ... Ejector cylinder, 9 ... Ejector rod, 16
... Mold operation switching valve, 17 ... Mold clamping pipe, 18
...Mold opening pipe line, 21...Mold operation control timer, 23...Ejexion operation control timer,
30...Return spring, 31...Hydraulic oil pipe.

Claims (1)

[Claims] 1 Lower space 3 of lower mold 2 installed on mold plate 1
an ejector plate 4 provided vertically movably therein; an ejector cylinder 8 provided at the bottom of the template; and the ejector cylinder 8.
The tip protrudes from the ejector plate 4.
an ejector rod 9 in contact with the mold plate, a mold clamping cylinder 6 that moves up and down the mold plate, and a mold clamping pipe 17 and a mold opening pipe 18 connected to the mold clamping cylinder 6.
In the ejector rod drive device for an injection molding machine, the ejector rod drive device includes a return spring 30 that urges the ejector rod 9 in the backward direction into the ejector cylinder 8.
and furthermore, the ejector cylinder 8
An ejector rod drive device for an injection molding machine, characterized in that a hydraulic oil pipe 31 is connected to the mold opening pipe 18.