JPS6161897B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive device for a column nut in a molding machine such as a die casting machine or an injection molding machine.

Generally, in an injection molding device, a fixed mold and a movable mold are brought into contact with each other, and molten metal is injected into the mold cavity while a predetermined mold clamping force is applied by tightening both with a large force. Molding is in progress.

In such injection molding equipment, the mold clamping force is extremely large, ranging from hundreds to thousands of tons.
Multiple columns with large diameters can be extended by about 1.5 to 2 mm. In such equipment, the distance between the fixed plate and the movable plate when the mold is installed and clamped depends on the size of the mold and the type of molded product.
That is, it is necessary to adjust the die height according to the thickness of the mold and to delicately adjust the mold clamping force.

Normally, in die casting machines, etc., four column nuts attached to the link housing are simultaneously rotated via one chain, etc., to move the position of the link housing and movable platen, etc., adjust the die height, and clamp the mold. The force was adjusted, but in that case, an extremely small movement of the link housing etc. would result in a large change in the mold clamping force.

For example, assume that the mold clamping force is 800 tons, the difference between the maximum die height and the minimum die height, that is, the die height adjustment allowance is 500 mm, and the adjustment of this distance can be made in 5 minutes. Let's assume that the column will extend, for example, by 2 mm when it is fully loaded to 800 tons. Then, the desired minimum resolution for mold clamping force adjustment is 1% of the maximum mold clamping force, in this case 8 tons. Under these conditions,
Now, if we try to move the link housing by 8 tons corresponding to this resolution, we need to move the link housing by 0.02 mm, which is 1% of 2 mm.

However, the link housing was originally 500
Since it takes 5 minutes to move mm, it takes only 0.012 seconds to move 0.02 mm.

Therefore, it is impossible for humans to make such delicate adjustments in an extremely short period of time.

Furthermore, this adjustment has been extremely difficult due to hydraulic oil leakage and rotation lag time in the hydraulic motor.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a drive device for a column nut for a molding machine that is configured to ensure fine adjustment of mold clamping force.

In order to achieve the above object in the present invention, a hydraulic motor is used as a drive source for a column nut for a molding machine, and between the hydraulic drive source and the hydraulic motor,
A first switching valve that switches between continuous feeding and pitch feeding of the column nut, a second switching valve that switches between supplying and discharging hydraulic oil to the hydraulic motor, and a valve between the first switching valve and the second switching valve. One pressure port of the first switching valve is communicated with one chamber of the piston device, and the other pressure port of the first switching valve is connected to a piston device that can perform pitch drive. The other chamber of the piston device is provided in communication with the pressure input port of the second switching valve, and when the one chamber of the piston device communicates with the hydraulic drive source via the first switching valve. In this method, we used a device equipped with a piston that slides a predetermined stroke according to the resolution of mold clamping force adjustment.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

Figure 1 and the following diagrams explain one embodiment of the present invention, in which 1 is a fixed plate, 2 is a movable plate, and 3 is a link housing. A mold 2a is attached. 3a
is a column, and both ends of the column 3a are fixed by column nuts 4 on the outside of the movable platen 1 and the link housing 3.

5 is a mold clamping cylinder, 5a is a toggle mechanism, 6
indicates the machine base, and by turning the column nut 4 on the link housing 3 side, the link housing 3 can be moved along the column 3a to adjust the die height and mold clamping force. It is configured.

Chain foils 4a are formed on the circumferential surface of the column nut 4 rotatably attached to the link housing 3, and between these chain foils 4a and a chain foil 7a fixed to the output shaft of the motor 7 attached to the link housing 3. An endless chain 8 is wound around the die height, and the die height can be adjusted by turning four column nuts 4 at the same time by the action of a motor 7.

A hydraulic motor is used as the motor 7 in the molding apparatus having such a structure, and its hydraulic circuit is constructed as shown in FIG.

In FIG. 3, reference numeral 9 denotes a hydraulic pump, and between the hydraulic pump 9 and the hydraulic motor 7 there is an electromagnetically actuated first switching valve 10 for switching between continuous feed and pitch feed, and an actuator for the hydraulic motor 7. An electromagnetically actuated second switching valve 11 that switches oil is provided, and the B port, which is one pressure output port of the switching valve 10, and the P port, which is the pressure input port of the second switching valve 11, are provided. A piston device 12 capable of pitch driving is provided between the A port and the P port, which is the other pressure output port of the switching valve 10 and the P port, which is the input pressure port of the switching valve 11. 13 and a flow rate regulating valve 14 are provided.

The continuous feed is used when the link housing 3 is fed with a long stroke, and the pitch feed is used for inching, that is, fine adjustment, in order to control the mold clamping force.

The piston 15 of the piston device 12 is constantly pressed against the switching valve 10 side by a spring 16, and each time a push button of a control device (not shown) is pressed once, the switching valve 10 is switched. As a result, the piston 15 is pushed toward the switching valve 11 and driven in pitch, so that a predetermined amount of hydraulic fluid can be supplied to the hydraulic motor 7. The stroke of the piston 15 is predetermined according to the resolution of mold clamping force adjustment.

16 is a tank, and 17 is a check valve provided in piping between the switching valve 11 side of the piston device 12 and the tank 16.

In the state shown in FIG. 3, that is, the switching valve 10
If the solenoid 11a or 11b of the switching valve 11 is energized while the solenoid 10a of the switching valve 11 is demagnetized, the hydraulic fluid from the hydraulic pump 9 is transferred to the switching valve 1.
0, check valve 13, flow rate adjustment valve 14 and switching valve 1
1 to the hydraulic motor 7, the motor 7 continuously rotates in either forward or reverse direction, die height adjustment is performed, and when the solenoids 11a and 11b are demagnetized, the rotation is stopped.

When adjusting the mold clamping force, the solenoid 10a of the switching valve 10 is energized, and one of the solenoids 11a and 11b of the switching valve 11 is energized. in this case,
Solenoids 10a and 11a or 11b are energized at the same time, or solenoid 10a is energized slightly earlier. Then, switching valve 1
0 and 11 are switched, the hydraulic oil from the hydraulic pump 9 acts on the rear end of the piston device 12, moves the piston 15, which is at the retraction limit, forward by overcoming the pressing force of the spring 16, and moves the front end of the piston device 12 forward. The hydraulic oil in the side chamber is pushed out and sent to the hydraulic motor 7 through the switching valve 11, causing the hydraulic motor 7 to rotate slightly in a predetermined direction. In this case, the piston 15 stops at its forward limit, and the hydraulic motor 7 rotates by an amount corresponding to the forward stroke of the piston 15, that is, by an amount corresponding to the desired resolution of mold clamping force adjustment.

When the piston 15 moves forward, a signal based on the operation of a timer or position detection device (not shown) causes
The solenoid 11 of the switching valve 11 that was energized
a and 11b, and then the solenoid 10a of the switching valve 10 is demagnetized. Then, the piston 15 retreats due to the force of the spring 16 and the action of the hydraulic oil supplied to the front end side of the piston device 12 through the switching valve 10, the check valve 13, and the flow rate adjustment valve 14, and Return to the state shown in the figure.
At this time, depending on the degree of restriction of the flow rate adjustment valve 14, the hydraulic oil in the tank 16 can be sucked into the piston device 12 via the check valve 17.

Next, the switching valves 10 and 11 are operated, the piston 15 is moved back and forth a desired number of times by pitch drive, and the hydraulic motor 7 is rotated by a desired amount, thereby moving the column nut 4, link housing 3, etc. a desired distance. It can only be moved forward or backward.

By adopting such a structure, it is possible to control the operation of the hydraulic motor 7 with high accuracy by managing only the number of times the push button is pressed, and as a result, even extremely small mold clamping force adjustments can be made reliably. It can be done easily.

The piston device 12 can be driven manually by an operator pushing a push button, but it can also be driven automatically.

When automatically adjusting the mold clamping force, as shown in FIG. A force calculator 21 calculates the mold clamping force from this elongation.

At this time, if the desired mold clamping force is achieved, the work will be completed, but if the difference between the desired mold clamping force and the desired mold clamping force is larger than the allowable range, the average mold clamping force calculator will be applied. In 22, for example, 2 to 3
The average value of the mold clamping force when performing mold clamping is calculated, and the comparator 24 compares this actual average mold clamping force with the mold clamping force set value set by the mold clamping force setting device 23. and compare them, and obtain the deviation value, which is the difference.

Reference numeral 25 is a setting device for setting the resolution, that is, the tolerance range of the mold clamping force, and the value set here is compared with the excess or insufficient mold clamping force obtained by the comparator 24.
If the deviation value is within the permissible range, the comparator 25a recognizes it as a dead zone, and if it is outside the permissible range, the correction number calculator 26 determines the number of corrections, that is, how many times the pitch drive should be performed. It is determined.

Then, based on this calculation, the drive circuit 27 for the piston 15 is operated, and control is performed until the desired mold clamping force is reached.

Now, suppose that the set value of the mold clamping force is 800 tons, the set value of the allowable range is 8 tons, and the mold clamping force that can be changed by one operation of the piston device 12 is
8 tons, when the average mold clamping force is 750 tons, the deviation value of the mold clamping force calculated by the comparator 24 is
It will be 50 tons. Since this value is larger than the allowable range of 8 tons, it is calculated by the correction number calculator 26 and the number of corrections is 6. In this case, even if the piston device 12 is pitch-driven six times, the mold clamping force is still 2 tons short of the predetermined mold clamping force, but since this value is within the allowable range, the adjustment is completed after six corrections.

In the above-described embodiment, a synchronized rotational drive device in which four column nuts 4 are simultaneously rotated by a chain drive is used, but instead of this, a synchronized rotational drive device using a conventionally known spur gear device or a worm drive device may be used. It is also possible to use a synchronized rotational drive device with a connecting shaft or the like.

As is clear from the above description, according to the present invention, a hydraulic motor is used as a drive source for a column nut for a molding machine, and a switching valve and a piston device capable of pitch drive are provided between the hydraulic drive source and the hydraulic motor. Since this structure is adopted, extremely minute mold clamping force adjustments can be made reliably and easily.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a front view, FIG. 2 is a left side view, FIG. 3 is a hydraulic circuit diagram, and FIG. 4 is a block diagram showing a control device. 1... Fixed plate, 2... Movable plate, 3... Link housing, 3a... Column, 4... Column nut, 5... Mold clamping cylinder, 7... Hydraulic motor, 9... Hydraulic pump, 1
0, 11...Switching valve, 12...Piston device, 15...
Piston, 16...spring.

Claims (1)

[Claims] 1. A hydraulic motor is used as a drive source for a column nut for a molding machine, and a first switching valve is provided between the hydraulic drive source and the hydraulic motor to switch between continuous feed and pitch feed of the column nut, and a first switching valve for supplying and discharging hydraulic oil to the hydraulic motor. A second switching valve that performs switching and a piston device that is disposed between the first switching valve and the second switching valve and that can perform pitch drive are connected to one output pressure port of the first switching valve. The piston device is connected to one chamber of the piston device, and the other pressure port of the first switching valve is provided in communication with the other chamber of the piston device and the pressure input port of the second switching valve. ,
A piston is provided inside that slides by a predetermined stroke according to the resolution of mold clamping force adjustment when the one chamber of the piston device communicates with the hydraulic drive source via the first switching valve. A column nut drive device for a molding machine using a device that uses