JPS58107260A - Regulating method for upper limit of die clamping force in molding machine having toggle type die clamping mechanism - Google Patents

Abstract

PURPOSE:To avoid excessive reclamping by stopping die clamping operation when the stroke position for high pressure selection exceeds ths stroke position of a die clamping cylinder corresponding to a max. die clamping rate, that is, a max. die reclamping rate. CONSTITUTION:After dies D1, D2 are mounted respectively to the opposed surfaces of stationary and moving die plates 2, 4, oil pressure is fed to a die clamping cylinder 10 to clamp the dies with toggle mechanisms 5. Here, during die clamping, the stroke position thereof is detected with a potentiometer 19 or the like and the detected voltage Ex thereof is fed to an arithmetic device 20. The reference and set voltages E0, E1 corresponding to the stroke positions of the cylinder 10 at which the max. permissible die clamping force of the molding machine and the optional die clamping force to be set by the operator are generated are beforehand stored in the device 20. The voltage Ex is compared with the E0, E1, and when Ex=E1 and E1<=E0, a high-pressure changeover valve 16 is operated to interrupt a low-pressure relief valve 17, and when Exnot equal to E1or E1> E0, the valve 17 is held as it is and a selector valve 12 is operated toward die opening, whereby the die clamping operation is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for regulating the upper limit of the clamping force in a molding machine having a toggle type mold clamping mechanism.

Generally, in a molding machine that has a toggle type mold clamping mechanism,
A large mold clamping force can be generated by a small propulsive force of the mold clamping syringe, and the mold clamping force is determined by the amount of additional tightening. However, in a toggle type mold clamping mechanism, if the opening angle of the ribs forming the toggle mechanism approaches 180°, the clamping force (the clamping force) theoretically becomes infinite, so the upper limit of the mold clamping force becomes inaccurate, and retightening is required. If the amount is set too large, a mold clamping force exceeding the specifications may be generated and damage the entire area or ms.For this reason, conventionally, a relief valve was provided in the hydraulic circuit of the mold clamping syringe, but There was a risk that insufficient and excessive mold clamping force would be generated.

In addition, for molding machines with a toggle-type clamping mechanism, from the standpoint of mold maintenance, the mold is usually clamped at low pressure over the entire surface or up to the point of contact, to ensure that no foreign matter is attached to the mold surface. After checking, the pressure is switched to high and the mold clamping force is generated according to the amount of additional tightening. Utilizing the fact that there is a certain geometrical relationship, the standard stroke position of the mold clamping syringe corresponding to the maximum mold clamping force, that is, the maximum feed increase amount, is set in advance, and the switching position for high pressure switching is set in advance. , if this reference position is exceeded,
The feature is that excessive retightening is prevented by not operating the high pressure switching valve provided in the hydraulic circuit of the mold clamping system and completely stopping the mold clamping operation of the low pressure torque mechanism. The present invention provides a method for regulating the upper limit of mold clamping force in a molding machine having a toggle type clamping structure.

To explain an embodiment of the present invention with reference to the drawings, a tail stock (1) and a fixed tie plate (2) are connected to a tie bar (3).
A movable type plate (4) is disposed between the tail stock (1) and the fixed tie plate (2), and is movable using the tie bar (3) as a guide. (5) is a toggle mechanism, which has ribs (6) and (7) that are connected to each other in the refractive index, and one end of one of the ribs (6) is connected to the tailstock (1) by a movable tiller:
(4), and the other side (7).
) on the surface of the movable tie plate (4) facing the tail stock (1), and
Connect the connecting part of the cross head (
9), and the locking cylinder head (9) is installed on the outer end surface of the tail stock (1).
It is stuck to the tip of the tube. The mold clamping syringe 〇〇 connects and communicates its 0tsudo side chamber (LUA) with the TASIKU (2) via the electromagnetic switching valve 0'4, and also connects the head side chamber +
10b) is connected to the hydraulic boss q through the electromagnetic switching valve (2), and the oil removal stopper shifter (b) is driven by the t-t-Q5. ah is a high-pressure switching valve installed on the input side of the hydraulic circuit, Q'I) is a low-pressure relief valve, and (g) is a force valve. It is possible to obtain an output voltage proportional to the stroke position of the mold-clamping syringe by using a position sensor such as a boticometer attached to the syringe. It is connected to the kneading device kiln, and the output end of the kneading kiln is connected to a high pressure switching valve (6) provided in the hydraulic circuit.

The configuration is as above, and the fixed tie plate (
2) and the movable tie plate (4) respectively.
After installing Dl) and (I)l), drive the hydraulic boss (b) to send hydraulic pressure to the head side chamber (10b) of the mold clamping cylinder Q1 via the electromagnetic switching valve 0, and the toggle mechanism The method of the present invention is to perform mold clamping through (to)).

When the mold is closed, the stroke zero position is detected by a bothesimeter, etc., and the detected voltage (EX
) to the arithmetic device -, the arithmetic device! A reference voltage (Eo) corresponding to the zero stroke position of the mold clamping syringe which generates the maximum mold clamping force stored in advance in the cage, and a clamping syringe which generates an arbitrary mold clamping force set by the operator. 4-QQ's set voltage (E r) corresponding to the stroke position and the second
Comparison and judgment are performed according to the flowchart shown in the figure. That is, when Ex==Et and 1ift≦No, the high pressure switching valve (7) is operated to open the low pressure relief valve αη! Cut the mold and switch to high pressure mold clamping. Also, Ex==E1.
1 or El>Eo, the low pressure relief valve α force is left as is, the electromagnetic switching valve (2) is opened, the mold clamping operation is stopped, and an alarm is issued by a buzzer or the like.

As described above, in a molding machine having a toggle-type mold clamping mechanism, the present invention stores in a calculation device a reference amount rEo corresponding to the stroke position of a mold clamping syringe that generates the maximum allowable mold clamping force. Then, input the amount (El) corresponding to the stroke 0 position of the mold clamping syringe, which generates a desired mold clamping force set by the operator, into the calculation device, and perform mold clamping at low pressure. While detecting the voltage [E] equivalent to the stroke position of the syringe with a position sensor such as a hotelometer, input it to the calculation device.
When the illusion becomes equal to (El), (El) or (Eo)
or if (let) is less than (EO),
The calculation device sends an activation signal to the high pressure switching valve installed in the hydraulic circuit of the mold clamping syringe to generate a mold clamping force equivalent to (El), and if (Σ1) is greater than (EO), the high pressure switching valve is activated. This method relates to a method for regulating the upper limit of mold clamping force in a molding machine having a toggle type mold clamping mechanism, which is characterized by keeping the pressure at a low level without activating the mold. It is possible to purposefully prevent the generation of excessive mold clamping force, which has been a drawback in machines, and prevent damage to molds and machines.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an explanatory diagram showing an outline of the operation circuit of the mold clamping cylinder and the mold clamping mechanism, and FIG. 70-
It is a chart. (5)...e toggle structure, (lC1...-mold clamping silicator, (6), anti-high pressure switching valve, 40...botisshiometer, wire...computing device〇Patent applicant Toyo Kishu Metal Co., Ltd. Agent, Patent Attorney Fusa Nakao] To Gire＼ and β

Claims (1)

[Claims] ■ In a molding machine having a toggle type mold clamping mechanism, a reference amount (Ko) corresponding to the stroke position of a mold clamping syringe that generates the maximum mold clamping force is stored in the calculation device. , an amount (E) corresponding to the stroke position of the mold clamping cylinder that generates the arbitrary mold clamping force set by the operator is input into the calculation device, and the mold is clamped at low pressure, and the stroke of the mold clamping syringe is 0. − Voltage corresponding to the lower position +]
cx) is detected by a digitizer such as a boticometer, and is input to the arithmetic device, and (Ex)
or (El), then (El) or 1Ek))
is equal to or if (El) is smaller than (EO), the arithmetic unit generates a mold clamping force equivalent to (El) by controlling the high pressure switching valve installed in the hydraulic circuit of the mold clamping syringe. A method for regulating the upper limit of mold clamping force in a molding machine having a toggle type mold clamping mechanism, in which if (El) is larger than (KO), the high pressure switching valve is not operated and the pressure remains low.