JPH0148852B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold clamping device used for high-speed opening/closing and clamping of a mold included in an injection molding machine.

In order to open and close molds at high speed, hydraulic clamping devices equipped with a rapid-feed cylinder and a booster ram outside the mold clamping cylinder include those with a structure that has a passage that reduces hydraulic resistance when opening the mold. Compared to a mold clamping device using a chisel, the device is longer due to the rapid feed cylinder, and the mold clamping chamber tends to become under negative pressure during high-speed mold closing.

This invention was devised in order to solve the above-mentioned conventional drawbacks, and there is no need to connect a rapid feed cylinder or a booster ram to the mold clamping cylinder as in the conventional case, and it also eliminates the need to connect a rapid feed cylinder or booster ram to the mold clamping chamber side during rapid feed. The object is to provide a space-saving, low-cost mold clamping device that does not generate negative pressure, operates smoothly, and does not cause shocks even when operated at high speed.

The present invention for the above-mentioned purpose comprises a mold clamping ram in a mold clamping cylinder with an open-ended cylinder, and the mold clamping ram is equipped with a fast-forwarding cylinder consisting of an open-ended cylinder together with a piston at the rear end. The inside of the ram is formed as a rapid-feeding oil chamber, and the tip of the ram, which is provided in the quick-feeding oil chamber by penetrating the piston of the mold-clamping ram from the rear end of the mold-clamping cylinder, is inserted into the rapid-feeding cylinder. The piston forms an oil chamber in the rapid-feeding cylinder that communicates with the hydraulic supply and drainage passage inside the ram, and a passage between the rapid-feeding oil chamber and the mold-clamping oil chamber is bored in the piston of the mold-clamping ram. A disc valve for opening and closing the passage is movably provided in the central core of the piston located around the ram on the oil chamber side, and the disc valve and the core communicate with the mold oil opening chamber via a hydraulic passage. It is characterized by being provided with an oil chamber for opening the disc valve.

The present invention will be explained in detail below using illustrated examples.

In the figure, 1 is a mold clamping cylinder, and 2 is a mold clamping ram, which has a cylinder that is open at its tip. 3 is a mold clamping oil chamber, and 4 is a mold opening oil chamber formed between the mold clamping cylinder 1 and the mold clamping ram 2.

The mold clamping ram 2 is equipped with a rapid feed cylinder 5, which is a cylinder with an open end, together with a piston 6 at the rear end, thereby forming a rapid feed oil chamber 7 within the mold clamping ram 2. Inside the rapid feed cylinder 5, the piston 8 of the mold clamping ram 2 runs from the rear end of the mold clamping cylinder 1 to the piston 8 of the mold clamping ram 2.
The piston 10 at the tip of the ram 9 provided in the center of the rapid-feed oil chamber 7 is inserted through the ram 9, and the pressure oil supplied to the rapid-feed cylinder 5 from the pressure oil supply/discharge passage 11 provided through the ram 9 is inserted. Thus, the rapid feed cylinder 5 is adapted to move within the mold clamping ram 2.

Reference numeral 12 denotes a passage bored in the piston 8 of the mold clamping ram 2, which is opened and closed by a disc valve 13 in the mold clamping oil chamber 3. The disc valve 13 protrudes toward the mold clamping oil chamber 3 and is movably provided in the central core 14 of the piston 8 located around the ram 9. , an oil chamber 15 for opening the valve is provided. This oil chamber 15 communicates with the mold opening oil chamber 4 via a hydraulic path 16 in the piston 8, and when pressurized oil is supplied from the mold opening oil chamber 4, the disc valve 13 is opened and the passage 12 is opened.
is opened, and the mold clamping oil chamber 3 and rapid feed oil chamber 7 are communicated with each other.

Note that 17 is a mold mounting member attached to the tip of the mold clamping ram 2.

The relationship between the above oil chambers and strokes is as follows.

However, B: Effective cross-sectional area of the mold clamping oil chamber 3 S: Stroke of the mold clamping ram 2 A: Effective cross-sectional area of the rapid-feeding oil chamber 7 C: S' of the mold-opening oil chamber 4 S': Rapid-feeding cylinder 5 (piston 6) ) stroke In the case of Fig. 2 B×S=(A×S)+(A×S′)……S′=(B−A)S/A In the fourth case B×S=(A+S)S+A× S'...S'=(B-A-C)S/A Therefore, in the example shown in FIG. 4, S' can be smaller than in the example shown in FIG.

Next, the effect will be explained.

High Speed Mold Opening In the state shown in FIG. 2, valves V ₁ , V ₂ , and V ₃ are switched to side a, and pressure oil is supplied from pump P to rapid feed cylinder 5 via pressure oil supply/discharge path 11 . The fast-feeding cylinder 5 moves at high speed in the direction of contracting the fast-feeding oil chamber 7, and as a result, the pressure oil in the fast-feeding oil chamber 7 flows into the passage 12.
It flows out into the mold clamping oil chamber 3. Since the mold clamping oil chamber 3 is in a reduced state, the mold clamping ram 2 is moved at high speed in the mold closing direction by a stroke equal to the inflow amount of pressure oil.

Strong mold clamping When the supply of pressure oil to the rapid feed cylinder 5 reaches its limit, that is, when high-speed mold closing is completed, the valves V ₁ and V ₃ are switched to b side and V ₂ to neutral, and the pressure oil is switched to the mold. The oil is supplied to the oil tightening chamber 3. At this time, the pressure oil in the mold opening oil chamber 4 side and the rapid feed cylinder 5 is controlled by valve V _2.
is returned to the tank, and at the same time disc valve 1
The resistance in the oil chamber 15 of No. 3 also disappears, and the disc valve 13 closes in the passage No. 1 due to the pressure on the mold clamping oil chamber 3 side.
2 is closed and the mold is strongly clamped.

Strong mold opening From the state shown in Figure 3, move valves V ₁ and V ₃ to side a.
When switched to the V ₂ b side, pressure oil is supplied from the pump P to the mold opening oil chamber 4.

Therefore, pressure oil is also supplied to the oil chamber 15 via the hydraulic path 16, and the disc valve 13 is operated to open the passage 12. As a result, the pressure oil in the mold clamping oil chamber 3 is supplied to the mold clamping oil chamber 3 as the mold clamping ram 2 moves. It flows into the rapid oil chamber 7. At this time, the rapid feed cylinder 5 is connected to the tank, and the rapid feed cylinder 5 also moves to expand the fast feed oil chamber 7, and a strong mold opening occurs there.

High-speed mold opening When the above-mentioned strong mold opening is completed, switch only valve _V2 to neutral. As a result, the mold opening oil chamber 4
The hydraulic path of the rapid feed cylinder 5 is connected to the connection circuit of the pump P and the pump P. In this case, there is a difference in area between the oil chamber of the rapid feed cylinder 5 and the mold opening oil chamber 4, and the area on the mold opening oil chamber side is larger, so the hydraulic circuit generated there becomes an operating circuit, and the rapid feed cylinder 5 has a piston. 6 is moved to the right side in the drawing due to the hydraulic pressure in the rapid feed oil chamber 7. Therefore, even if it is connected to the pump P, the hydraulic pressure in the oil chamber will be discharged to the hydraulic path.

This discharged pressure oil is added to the pressure oil supplied from the pump P and is supplied to the mold opening oil chamber 4, so that a larger amount of pressure oil than the pump discharge amount is supplied to the mold opening oil chamber 4. As a result, the mold can be opened at high speed.

Note that during strong mold clamping, the amount of oil in the mold clamping oil chamber 3 increases slightly, and this is discharged from the relief valve _V5 when the mold opens. In this way, the state shown in FIG. 2 is reached, and the mold opening process is completed.

The hydraulic circuit shown in FIG. 4 shows a case in which a valve _V4 is added to the circuit of the rapid feed cylinder 5 to slow down mold opening.

Further, in the above embodiment, the piston 8 is provided with the passage 12, but it is also possible to communicate the mold clamping oil chamber 3 and the rapid feed oil chamber 7 by using the ram 9. Therefore, the present invention is not limited to the above embodiments.

As mentioned above, this invention has a fast-feeding oil chamber and a fast-feeding cylinder in the mold clamping ram to enable high-speed opening/closing and mold clamping, so the mold clamping device is shorter than that of conventional structures. It is possible to save space and cost. In addition, when the mold is opened at high speed, the pressure oil in the mold clamping oil chamber flows into the fast feed oil chamber, and when the mold is closed at high speed, the pressure oil in the fast feed oil chamber flows into the mold clamping oil chamber, so there is negative pressure in these oil chambers during fast feed. It is difficult to cause problems, the operation is smooth, and there is no shock even when operating at high speed. Further, by switching the differential circuit between the mold opening oil chamber and the rapid feed oil chamber, there is an advantage that the initial mold opening force can be increased without sacrificing high-speed mold opening.

[Brief explanation of drawings]

The drawings illustrate the mold clamping device of the injection molding machine according to the present invention, and FIG. 1 is a vertical side view, FIG. 2 is a vertical side view when the mold is stopped opening, and FIG. 3 is a vertical cross-sectional view when the mold is clamped with force. The side view and FIG. 4 are longitudinal sectional side views showing another example of the hydraulic circuit during high-speed mold closing. 1...Mold clamping cylinder, 2...Mold clamping ram, 3...
Mold clamping oil chamber, 4... Mold opening oil chamber, 5... Rapid feed cylinder, 6... Piston, 7... Rapid feed oil chamber, 8... Piston, 9... Ram, 11... Pressure oil supply/drainage path , 12
...Passage, 13...Disc valve, 15...Oil chamber.

Claims (1)

[Claims] 1 The clamping ram in the mold clamping cylinder is configured with a cylinder with an open tip, and the clamping ram is equipped with a fast feed cylinder consisting of a cylinder with an open tip, together with a piston at the rear end, to supply quick feed oil inside the mold clamping ram. The tip of the ram, which is formed in a chamber and penetrates the piston of the mold clamping ram from the rear end of the mold clamping cylinder and is provided in the fast feed oil chamber, is inserted into the quick feed cylinder, and the inside of the fast feed cylinder is moved by the piston at the tip of the ram. It is formed in an oil chamber that communicates with the hydraulic pressure supply and discharge passage inside the ram, and a passage between the rapid feed oil chamber and the mold clamping oil chamber is bored in the piston of the mold clamping ram, and a passage is formed around the ram on the mold clamping oil chamber side. A disc valve for opening and closing the passage is movably provided in the central core of the piston, and oil for opening the disc valve is connected to the mold oil opening chamber via a hydraulic path between the disc valve and the core. A mold clamping device for an injection molding machine characterized by having a chamber.