JPS5914301B2 - Molding machine mold opening/closing device - Google Patents

Description

Detailed Description of the Invention The present invention relates to a mold opening/closing device for vertical casting machines, etc., and in particular, in a direct pressure type using fluid pressure such as hydraulic pressure, the mold opening/closing speed is efficiently controlled and the mold closing time is shortened. The present invention relates to a mold opening/closing device that enables smooth mold opening/closing.

A toggle link mechanism is used to open and close the mold in a vertical casting machine, but this makes the mechanism complicated and large.

By the way, when controlling mold opening and closing, especially mold closing, it is necessary to control the speed slowly in the initial stage, quickly in the middle stage, and slowly in the final stage just before closing the mold, and it is necessary to control the speed accurately. Otherwise, there is a risk that the movable mold and the fixed mold will collide and be damaged, so a toggle link mechanism is used as described above to control the speed. A direct pressure type using a hydraulic cylinder unit in place of the toggle link type mold opening/closing device described above has been proposed, but there are problems such as it is not as fast as the toggle link type, and it also requires speed control, especially deceleration. In the past, the hydraulic circuit was switched using a solenoid switching valve.
Since the amount of oil supplied to the cylinder is changed in stages, shocks occur, which is undesirable for operation.

The present invention is proposed to improve the above-mentioned disadvantages of such a direct pressure type mold opening/closing device using fluid pressure, and its purpose is to provide an electric flow rate control directional switching valve (servo valve) for controlling the moving speed of the piston. is controlled by a control circuit, and in the hydraulic control by the switching valve to the cylinder that drives the piston, the hydraulic pressure on the piston discharge side is merged with the hydraulic pressure on the mold closing side from a bypass passage with a check valve interposed during mold closing operation. , provides a mold opening/closing device that can quickly and smoothly perform the mold closing movement in conjunction with control by the switching valve, and also provides a pilot check valve before the branch of the bypass passage on the piston discharge side to shut off the passage. Another object of the present invention is to provide a mold opening/closing device that controls the mold closing operation of a cylinder.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 shows a control circuit diagram of the device according to the present invention, Figs. 2 and 3 show a front view and a side view of the main parts of the casting machine, Fig. 2 shows the mold in the open state, and Fig. 3 shows the casting machine in the open state. Each figure shows the mold closed state.

The casting machine 1, as shown in FIGS. 2 and 3, has a fixed plate 4 at the upper end of a tie bar 3 that stands up on a base plate 2, and a movable plate 5 is slidably fitted into the tie bar 3 between the fixing plates 4. and board 2
A lower mold 6 is mounted and supported on the upper part, and an upper mold 7 is mounted and supported under the movable plate 5.

A mold opening/closing cylinder unit 8 is installed on the center of the fixed plate 4, and the cylinder 8a has a piston 8b slidably fitted therein, and the piston rod 8e extends downward from the cylinder 8a. The vertical through hole 4a in the center of the fixing plate 4
The distal end thereof is connected to the center portion of the movable plate 5 through the movable plate 5. Therefore, the movable plate 5 moves up and down as the piston 8b moves up and down due to the introduction and discharge of pressure oil into the cylinder, thereby opening and closing the mold. Reference numeral 9 in the drawing is a mold clamping cylinder unit, in which the rod 9c of the piston 9b fitted into the cylinder 9a is fitted and received in the vertical hole 5a of the movable plate 5 when the mold is opened, and the rotation on the movable plate 5 when the mold is closed. The moving plate 10 is rotated to close the vertical hole 5a, and the pressure of the rod 9e is transmitted to the movable plate 5 via the rotating plate 10, and the upper mold is pressurized to clamp the mold, as shown in FIG. It was shown in To explain the present invention based on FIG. 1, the electric flow rate control directional valve (servo valve) 11 has a neutral shutoff position A in the figure and a mold closing position B offset to the right, which is formed by an X-shaped spool. , and a left-offset mold opening position C consisting of parallel spools.

A line 12 at the upper end of the cylinder 8a above the piston 8b and a line 13 at the lower end of the cylinder 8a below the piston 8b are led in parallel to the cylinder side of the switching valve 11, and a pump 15 is connected to the oil tank 14 side of the valve 11. Connected pressure oil line 1
6 and a discharge line 17 are led in parallel. The electric flow rate control directional switching valve (servo valve) 11 is controlled by a control device D as shown in FIGS. 1, 4 to 6. Connect any part of the rod 8c that moves the movable plate 5 up and down, or any part of the movable plate 5 to the belt-shaped movable member 18,
Via this movable member 18 it is connected to a potentiometer 19 which acts as a position detector.

Therefore, as the rod 8c moves, the actual amount of movement, that is, the position, of the movable plate 5 is measured via the movable member 18 and output as a voltage value. The position detector 19 functions as a position detector for the rod 8c with characteristics as shown in FIG. Reference numeral 20 denotes a potentiometer that acts as a position setting device, and the position setting device specifies a shift position such that the moving speed of the piston rod 8c is changed to a predetermined speed at the movement position (elevating movement position) of the piston rod 8c. The set position is output as a voltage value.

A plurality of position setting devices 20 are provided as shown in FIG. 5, and each of the position setting devices 20-1 to 20-n controls the multi-stage speed change of the movable plate 5 that supports the piston rod 8c and therefore the upper die. The location is specified. Reference numeral 21 denotes a voltage comparator, into which the output of the position detector 19 and the output of the position setting device 20 are input, respectively, and the magnitudes thereof are compared.

As shown in FIG.
It is provided corresponding to 0. The outputs compared by the comparator 21 are inputted to the flow rate controller 22 via the amplifier 23, which actuates an adjustable control element that sets the piston 8b at a desired speed, and is controlled by the electrical signal of the element. The pilot flow rate of the electric flow rate control directional switching valve (servo valve) 11 is controlled to control the main flow rate of the valve 11, and the piston 8b is brought to a predetermined speed. To explain the configuration of the control device in more detail with reference to FIG. 5, a plurality of position setters 20-1 to 20-n are prepared for one position detector 19, and in each position setter, a comparator 21- 1 to 21-n and amplifier 2
3, that is, 23-1 to 23-n.

The outputs of the amplifiers 23-1 to 23-n are connected to control elements 22-1 to 22-n provided within the flow rate controller 22.
Each of the control elements 22-1 to 22-n can be adjusted to set the piston 8b to an arbitrary speed. The voltage output of the position detector 19 is input to all comparators 21-1 to 21-n,
On the other hand, each of the comparators 21-1 to 21-n receives the voltage value of a position setting device 20-1 to 20-n, which can change the output voltage of a corresponding sliding resistor. The set voltages of the position setters 20 to 1 to 20-n are set to increase as the auxiliary number n increases, taking into account the piston speed or the output characteristics of the position detector shown in FIG.
When the output voltage of the position detector 19, which is output according to the characteristics shown in FIG. 6, becomes higher than the set voltage, the corresponding comparator outputs an output and operates the corresponding control element via the next stage amplifier. This acts to cause the piston 8b to reach a speed preset by the control element via the electric flow rate control directional switching valve 11. FIG. 4 shows an example of the relationship between the amount of movement of the piston, that is, the amount of descent for mold closing, and the speed. When hydraulic pressure is applied to the upper surface of the piston 8b of the cylinder unit 8, the piston 8b begins to move downward (the fourth (point A in the figure), initially moves at low speed for starting (state a in Fig. 4), and in the low speed state, the output voltage of the position detector 19 is higher than the set voltage of the position setting device 20-1, Comparator 21-1, amplifier 23-
1. This is done by controlling the electric flow rate control directional switching valve 11 via the control element 22-1 to slow down the speed of the piston 8b.

Next, when the piston 8b moves further down and exceeds the middle point in FIG. The robot is moved at high speed (state b in FIG. 4).

When the piston 8b further moves downward and reaches a position close to the lower limit of movement (point C in Fig. 4), the output voltage of the position detector 19 becomes larger than the set voltage of the position setting device at this position, and the above occurs. Similarly, the control element rapidly increases the speed of the piston 8b to a low speed state (c in FIG. 4), and then stops the piston 8b at point 2 in FIG.

Thus, the mold closing movement, that is, the downward movement of the piston 8b, is stopped.
This deceleration movement prevents the upper and lower molds from colliding, brings the molds together smoothly and without impact, and closes the mold. By adjusting the position setters 20-1 to 20-n in this way,
At any position of the piston 8b, the control elements 22-1 to 22-2
By adjusting 2-n, the speed of the piston 8b can be selectively changed to an arbitrary speed.

A check valve 24 that allows pressure from the pump 15 is interposed downstream of the pump 15 in a line 16 connected to the pump 15 on the tank 14 side of the electric flow rate control directional switching valve 11, and a check valve 24 is provided between the lower end of the cylinder 8a and the switching valve. A check valve 25 is interposed on the side of the line 13 connecting the valve 11 to the valve 11, which cuts off pressure from the lower surface of the piston 8b and allows pressure from the valve 11 side.

The check valve 25 of the line 13 is branched 26 at an appropriate position on the cylinder 8a side, and the line 27 branched from the branch point is connected to the check valve 2 of the line 16 having the pump 15 described above.
4 downstream to form a bypass line. The bypass line 27 is provided with a check valve 28 that allows the hydraulic pressure below the piston 8b of the cylinder and blocks the hydraulic pressure of the pump 15 that has passed through the check valve 24. In the drawing, reference numeral 29 denotes a relief valve, which is interposed in a control line 30 branched between the pump 15 of the line 16 and the check valve 24, and controls the operation of the switching valve 11. Next, to describe its function and effect, as shown in FIG. 1, the piston 8b is at the upper limit position in the cylinder 8a and the mold is open, and the movable plate 5 supporting the upper mold 7 is moved to the upper limit position by the rod 8c. It is in.

The electric flow rate control directional switching valve 11 is moved to the left from the illustrated neutral position A, and the lines 12 and 13 are connected to the lines 16 and 17 at position B. Pressure oil from the pump 15 is supplied from the valve 11 to the line 12 through the check valve 24 through the line 16 and introduced onto the piston 8b in the cylinder 8aτ.
Move the piston 8b downward. The downward movement speed, that is, the mold closing speed, is determined by operating the switching valve 11 by comparing the predetermined setting device 20 with the detector 19 that measures the moving position of the piston 8b as described above. It is held on As the piston 8b moves downward within the cylinder 8a, the oil below it is discharged through the line 13, and the oil that has flowed into the line 13 is blocked by the check valve 25, so that the oil flows through the bypass line 27 and check valve 28. via line 16
to join.

The check valve 24 prevents the discharged oil from flowing downward toward the pump 15, which joins the line 16, and joins the oil from the pump 15 to be supplied onto the piston 8b via the lines 16 and 12. Therefore, the amount of oil supplied by the pump 15 can be equal to the volume of the piston rod 8c, and the capacity of the pump 15 can be reduced. In this way, the mold can be closed quickly and smoothly without damaging the molds by reducing the speed during mold matching, and the above can be performed quickly and smoothly while controlling the speed. When opening the mold, the switching valve 11 is moved to the right from the neutral position A in the figure to face the line to position C.

As a result, the lines 16 and 13 are communicated, and the hydraulic oil passes through the check valves 24 and 25 to the piston 8b of the cylinder 8a.
The hydraulic pressure flows downward and moves the piston 8b upward, and since the hydraulic pressure is blocked by the check valve 28, the flow into the bypass line 27 is prevented. On the other hand, the oil on the top surface of the piston 8b is returned to the tank 14 via lines 12 and 17, and the amount of oil supplied into the cylinder 8a to move the piston 8b upward is calculated by subtracting the volume of the rod from the piston volume. Since it is a small amount, the rod volume can be reduced. As described above, the mold opening/closing speed can be smoothly controlled by controlling the electric flow rate control directional valve (servo valve), the mold can be closed smoothly while shortening the mold closing time, and the hydraulic oil can be used effectively and Since the circuit configuration can be used effectively, it is possible to control the mold closing speed efficiently.

FIG. 1 includes the second invention of the present invention, and includes the previously described cylinder 8a.
A pilot check valve 31 is provided on the cylinder side of the branch passage 26 of the line 13 below the piston 8b at the lower end.

The pilot check valve 31 is controlled by a solenoid switching valve 32, and a check valve 34 and a pilot check valve 35 are sequentially interposed from the switching valve 32 side in a line 33 connected to the pilot check valve 31 by the switching valve 32. is moved to the left from the neutral position E shown in the figure to position F, thereby applying hydraulic pressure from the line 16 via the auxiliary line 36 to the line 33, the check valve 34, and the check valve 35, and the pilot check valve 31 is activated via the line 33a. Line 13 when opening and closing the mold
Allow oil to flow in the direction of discharge. The electric flow rate control directional switching valve 11 essentially causes oil leakage due to its function even if the line is cut off, and it is difficult to improve the accuracy of stopping at a predetermined position. In particular, when the piston 8b is suddenly stopped at an intermediate position of downward movement, that is, an intermediate position of mold closing, or is held at an intermediate position, it is desirable to provide an auxiliary mechanism to ensure this. In this case, the solenoid switching valve 32 is switched to shut off the line 13 using the pilot check valve 31. As a result, the line 13 is cut off before the electric flow rate control directional switching valve 11, and the downward movement of the piston 8b is locked, so that it is accurately stopped at a predetermined position. Therefore, when opening and closing the mold, the mold can be precisely stopped at a predetermined position while controlling the mold opening/closing speed using an electric flow rate control directional switching valve (servo valve). As is clear from the above, according to the present invention, the mold opening/closing speed can be efficiently controlled using direct pressure rather than hydraulic pressure, reducing the mold opening/closing time and improving work efficiency, and the above can be achieved by electrical flow rate control. This can be done with a simple circuit configuration such as a directional control valve control device and a check valve.

Further, due to the above, the stopping operation at a predetermined position can be performed accurately with increased precision, and the above-mentioned operation can be accomplished simply by interposing a pilot check valve in the circuit, which has many advantages.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; Fig. 1 is an explanatory circuit diagram of the device according to the present invention, Fig. 2 is a front view of the main parts of the casting machine when the mold is open, and Fig. 3 is the same when the mold is closed. A similar side view of the state, Fig. 4 is a diagram showing an example of the relationship between piston movement amount and speed, Fig. 5 is a circuit configuration diagram of the control device, and Fig. 6 is the output of the position detector. FIG. 3 is a diagram showing characteristics. In the drawings, 1 is a molding machine, 8 is a cylinder unit, 8a is a cylinder, 8b is a piston, 19 is a detector, 20 is a setting device, 22 is a flow rate controller, 11 is an electric flow rate control directional valve, 13, 16 is a line, 15 is a hydraulic source, 14 is a tank,
24, 25, and 28 are check valves, 27 is a bypass line, and 31 is a pilot check valve.

Claims (1)

[Claims] 1. A detector that measures the piston movement position of the mold opening/closing cylinder, a setting device that predetermines the shifting position of the moving piston, and a comparator that compares the outputs from the detector and the setting device. , an electric flow rate control directional switching valve that controls the moving speed of the piston, and a flow rate controller that inputs the output from the comparator and gives a speed change command to the switching valve, A check valve is provided in the line below the piston, and the cylinder side of the line having the check valve is bypassed to the hydraulic source side of the switching valve. A mold opening/closing device for a molding machine, characterized in that it is connected to the line via a check valve. 2. A detector that measures the piston movement position of the mold opening/closing cylinder, a setting device that predetermines the shifting position of the moving piston, a comparator that compares the outputs from the detector and the setting device, and a piston movement speed. an electric flow rate control directional switching valve that controls the switching valve; and a flow rate controller that inputs the output from the comparator and gives a speed change command to the switching valve; A check valve is provided in the line below the piston, and the line is connected to the hydraulic pressure source and tank via a line, and the line is connected between the check valve and the bottom of the piston to prevent side movement of the piston when necessary. A molding machine characterized in that a pilot check valve for shutting off is provided, and a line between the pilot check valve and the check valve of the line is bypassed and connected to a line on the hydraulic pressure source side of the switching valve via the check valve. Mold opening/closing device.