JPH0377078U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram showing the configuration of a hydraulic pressure supply device for an injection molding machine according to an embodiment of this invention, and FIG. 2 is a hydraulic circuit diagram showing a conventional example. Explanation of symbols of main parts, 100...Hydraulic supply device, 102...Variable displacement pump, 104...Proportional electromagnetic flow control valve, 106...First throttle, 108
... Proportional electromagnetic relief valve, 110 ... Pressure compensation valve, 112 ... Discharge amount variable element, 114 ... Pressure control valve, 116 ... Surge cut-off valve, 118 ...
...Safety valve, 120...Second throttle, 122...Solenoid switching valve, 124...Another electromagnetic switching valve, 7...Oil passage.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A hydraulic supply device for supplying pressure oil to a pressure oil supply path leading to a mold opening/closing actuator and a resin injection actuator of an injection molding machine, which comprises a variable displacement pump and the pump. a proportional electromagnetic flow control valve that proportionally controls the flow rate of pressure oil sent from the discharge port to the pressure oil supply path according to a flow rate setting input signal; and a first throttle element whose one end is connected to the discharge port of the pump. A proportional electromagnetic relief valve that is connected to the other end and causes a part of the pump discharge pressure oil to flow out to the tank line through the first throttle element when the discharge pressure of the pump exceeds the set pressure according to the set input electric signal. and introduction of pilot pressure oil into the discharge amount variable element of the variable displacement pump in response to the differential pressure before and after the flow rate control valve caused by the flow of supply pressure oil.
a pressure compensation valve that changes the discharge amount of the variable displacement pump so as to keep the differential pressure constant by controlling discharge; a pressure control valve that is operated by a pressure difference to reduce the discharge flow rate of the variable displacement pump by introducing a portion of the pump discharge pressure oil to the discharge rate variable element; and an outlet side of the flow rate control valve at one end. receives the pressure of the pressure oil supply path from the other end, and receives the spring force and the set pressure of the proportional electromagnetic relief valve at the other end, so that the pressure of the pressure oil supply path is predetermined to be higher than the set pressure of the proportional electromagnetic relief valve. and a surge cut-off valve that releases the increased pressure to the tank line when the increased pressure exceeds the flow rate control valve, the second throttle element having one end connected to the outlet side of the flow rate control valve; An injection molding machine comprising: an electromagnetic switching valve that selectively switches and connects the other end of the first throttle element and the other end of the second throttle element to an electromagnetic relief valve. Hydraulic supply device for use. 2. The hydraulic pressure supply device for an injection molding machine according to claim 1, further comprising another electromagnetic switching valve that disconnects the inlet port of the proportional electromagnetic relief valve from the control circuit system of each of the valves and connects it to another oil passage.