JPS6350176B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold clamping device for an injection molding machine or a die casting machine (hereinafter referred to as a molding machine).

In the case of a direct pressure type mold clamping device in a molding machine, the movable die plate moved by the mold clamping device is switched from high speed to low speed just before the forward limit. Conventionally, when making this switch, the flow rate of pressure oil to the mold clamping cylinder was generally controlled by detecting the position of the movable die plate using a limit switch, etc. However, the flow rate easily fluctuated due to the influence of oil temperature, etc. Because it lengthens the low speed range,
The forward range was short, which led to long cycles and low productivity.

The purpose of the present invention is to eliminate such drawbacks, and the purpose of the present invention is to make a mold clamping device for a molding machine that smoothly switches between high and low speeds, and by making the position accurate, increases the high speed range, thereby increasing productivity. Our goal is to provide the following.

The present invention will be explained below with reference to figures showing one embodiment. A movable die plate 14 whose mold is clamped by a mold clamping cylinder 13 faces a fixed die plate 12 fixed to the frame 11, and four divers 15 fixed to the fixed die plate 12.
(Only the top and bottom two are shown in the figure) One side is
A mold clamping cylinder 13 is attached to the frame 11 so as to be able to slide on the frame 11 in the axial direction of the tie bar 15.
The nut 16, which penetrates through the mold clamping cylinder 13 and is rotatable with respect to the mold clamping cylinder 13, but is prevented from moving in the left and right direction,
It is attached to the mold clamping cylinder 13 by screwing into the threaded portion 15A.

A sprocket 17 is fixed to the end surface of the nut 16 on the anti-mold clamping cylinder 13 side, and when a chain (not shown) stretched across these four sprockets 17 is driven by a drive source (not shown), the nut 16
is rotated to change the thickness of the mold (not shown), the mold clamping cylinder 13 and the movable die plate 1
4 work together to adjust the thickness. A shaft 18 passing through the center of the tie bar 15 is fixed to one sprocket 17, and a handle 18A is attached to the end surface.
Fine adjustment of the mold thickness is possible by manually rotating the . Note that even without providing a driving source, the mold thickness can be adjusted by rotating the handle 18A.

A mold clamping ram 19 that generates a pressing force via a mold clamping cylinder 13 is fixed to the left side of the movable die plate 14 . The left side of the mold clamping ram 19 passes through the mold clamping cylinder 13 and extends into the boost cylinder 20, and a piston 21 is formed at the tip thereof, and a mold clamping piston 22 that is integral with the mold clamping ram 19 or separate from the mold clamping ram 19 is located in the middle. is provided. The mold clamping piston 22 also has an oil passage 23 that communicates the two chambers of the mold clamping cylinder 13.
is provided, and the movable die plate 1 of the oil passage 23
A recess 23A is formed on the 4 side. A lid 24 having two stages of large diameter and small diameter protrusions 24A and 25B is attached to the right opening surface of the mold clamping cylinder 13. Oil passage 23 and recess 23A
The flow of oil from the left chamber to the right chamber of the mold clamping cylinder 13 is initially restricted and finally closed. Electromagnetic switching valves 26 and 27 are provided for supplying and discharging pressure oil from the pump 25 to and from the mold clamping cylinder 13 and the boost cylinder 20.

Next, the operation of the present invention will be explained. To clamp the mold from the mold open state shown in the figure, first energize the a side of the electromagnetic switching valve 27 with the mold close signal, then pump 2
The pressure oil No. 5 flows into the left chamber of the boost cylinder 20 and moves the mold clamping ram 19, that is, the movable die plate 14, to the right at high speed. At this time, the electromagnetic switching valve 26 is in the neutral state shown in the figure. While the mold clamping ram 19 is moving to the right, the left chamber of the mold clamping cylinder 13 has a negative pressure, so the oil in the right chamber flows into it through the oil passage 23. At this time, the right chamber also has negative pressure, so the mold Oil in the tank 30 flows through the passage 28 of the tightening cylinder 13 and the pipe line 29. When the mold clamping ram 19 advances to the right and the small diameter protrusion 24A of the lid 24 fits into the recess 23A of the mold clamping piston 22, a narrow gap is formed, restricting oil flow, and the left chamber of the mold clamping cylinder 13 becomes negative. This builds up pressure and applies a brake, which reduces the mold clamping speed.
As the lid 24 moves further forward, the large-diameter protrusion 24B of the lid 24 fits into the recess 23A, closing the oil passage 23, preventing oil from flowing from the right chamber to the left chamber of the mold clamping cylinder 13, and creating a high negative pressure in the left chamber. It produces a strong braking effect. At the same time, the mold clamping piston 22 comes to a position where it closes the oil discharge passage 28 in the right chamber of the mold clamping cylinder 13, so that the oil in the right chamber flows out into the tank 30 in a constricted state. In this way, the left chamber of the mold clamping cylinder 13 becomes a negative pressure and the oil in the right chamber is squeezed and flows out to the tank 30, so the mold clamping ram 19 is braked and the switching from high speed to low speed is smooth. The location is
It is accurate because it is determined by the lid 24 and the mold clamping piston 22. After that, when the molds attached to both die plates 12 and 14 are aligned, the signal (the signal means is a limit switch, etc.) energizes the a side of the electromagnetic switching valve 26, so that the mold clamping piston 22 is moved to the left side. Generates strong mold clamping force by receiving pressure oil. In addition, the large diameter protrusion 24 of the lid 24
When B closes the oil passage 23 of the mold clamping piston 22, a dog attached to the mold clamping ram 19 etc. operates a limit switch (none of which is shown), and the electromagnetic switching valve 27 becomes neutral.

Next, the mold opening operation will be explained. The solenoid switching valves 26 and 27 are both energized on the b side by the mold opening signal, and pressure oil flows into the right chamber of the boost cylinder 20. At this point, the right and left chambers of the mold clamping cylinder 13 are filled with the oil of the mold clamping piston 22. The passage 23 is closed, and the right ventricle sucks oil from the oil tank 30 through the pipe 29, while the oil in the left ventricle flows out from the pipe 31 through the electromagnetic switching valve 26 to the tank 29; 31
Since the diameter is not that large, mold clamping ram 1 receives resistance.
9's left movement is relatively slow. When the mold advancement ram 19 moves slightly to the left, the protrusions 24A and 24B of the lid 24 separate from the mold clamping piston 22 and the oil passage 23 opens, so that the oil in the left chamber of the mold clamping cylinder 13 flows through the oil passage 23 to the right chamber. It flows into the tank via line 29. After this, the mold clamping ram 19 moves leftward at high speed by the pressure oil in the right chamber of the boost cylinder 20, and when the mold opening reaches its stroke limit, the mold opening ends.

Since the present invention requires the mold clamping ram 19 to make a full stroke, it is necessary to adjust the maximum mold opening amount according to the mold thickness of the mold. This is accomplished by rotating the nut 16 screwed onto the tie bar 15 according to the mold thickness via a sprocket 17 by a driving source (not shown). The maximum mold opening amount is finely adjusted using the handle 18A.

As described above, the mold clamping device of the molding machine according to the present invention includes a fixed die plate, a movable die plate that faces the fixed die plate and moves toward the fixed die plate, and a die opposite to the fixed die plate of the movable die plate. A mold clamping ram fixed to the side of the plate,
A boost cylinder that moves the movable die plate close to or separated from the fixed die plate by a piston formed on the end face of the mold clamping ram, and a boost cylinder that is provided in series with the boost cylinder and moves the movable die plate close to the fixed die plate. a mold clamping cylinder that applies a mold clamping force; a mold clamping piston that is located within the mold clamping cylinder and has an oil passage formed in the mold clamping ram and that communicates two oil chambers of the mold clamping cylinder; and the mold clamping cylinder. A passage provided to the oil chamber for draining the oil in the oil chamber on the movable die plate side to a tank, and a passage provided to the oil chamber to drain the oil in the oil chamber on the side of the movable die plate, which is attached to the opening surface of the mold clamping cylinder, and when the movable die plate approaches the fixed die plate, the mold The lid has a protrusion on one side that is fitted into the oil passage of the tightening piston to close the oil passage.

Therefore, in the present invention, an oil passage is provided in the mold clamping piston of the mold clamping cylinder to communicate the two oil chambers of the mold clamping cylinder, and a protrusion that closes the oil passage when the movable die plate approaches the fixed die plate is provided. The opening is provided on the lid of the mold clamping cylinder.
It has an extremely simple configuration. When the movable die plate approaches the fixed die plate and the convexity of the lid closes the oil passage, the oil chamber on the side opposite to the movable die plate of the mold clamping cylinder becomes negative pressure and brakes the movement of the mold clamping ram. At the same time, the passage of the oil in the oil chamber on the other side of the mold clamping cylinder to the tank is blocked by the mold clamping piston, so the oil flows out to the oil tank in a squeezed state, so the mold clamping ram moves at high speed. The present invention has the advantage that it can be smoothly switched from low speed to low speed, and that the switching position is accurate because it is determined by the positions of the mold clamping piston and the lid.

[Brief explanation of the drawing]

The figure is a longitudinal sectional view showing one embodiment of the present invention. 12... Fixed die plate, 13... Mold clamping cylinder, 14... Movable die plate, 19... Mold clamping ram,
20...Boost cylinder, 21...Piston, 24
...Lid, 24A, B...Protrusion, 22...Mold clamping piston, 23...Oil passage, 30...Passage.

Claims (1)

[Claims] 1. A fixed die plate, a movable die plate that faces the fixed die plate and moves toward the fixed die plate, and a mold fixed to the side surface of the movable die plate opposite to the fixed die plate. a clamping ram; a boost cylinder formed on the end face of the mold clamping ram and using a piston to move the movable die plate close to or away from the fixed die plate;
a mold clamping cylinder provided in series with the boost cylinder and applying mold clamping force to the movable die plate close to the fixed die plate; and a mold clamping cylinder located within the same mold clamping cylinder and formed on the mold clamping ram. a mold-clamping piston provided with an oil passage communicating two oil chambers; a passage provided to the oil chamber for draining oil in the oil chamber on the movable die plate side of the mold-clamping cylinder to a tank; a lid that is attached to an opening surface and has a protrusion on one side that fits into an oil passage of the mold clamping piston and closes the oil passage when the movable die plate approaches the fixed die plate; Mold clamping device. 2. The oil passage is provided in the recess on the moving die plate side, and the protrusion of the lid that fits into the oil passage is made into two stages with a small diameter part at the tip and a large diameter part at the base, and the small diameter part of the protrusion Claim 1, characterized in that when the large diameter portion of the protrusion fits into the recess, the oil flowing through the oil passage is throttled, and when the large diameter portion of the protrusion fits into the recess, the oil passage is closed. Mold clamping device for the molding machine described in Section 1.