JPH0225564Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a hydraulic pressure setting circuit for a hydraulic circuit in a die-casting machine or the like.

<Prior art> As shown in FIG. 2, the conventional oil pressure setting circuit was constructed by connecting a high pressure pump relief valve 3 and a low pressure pump relief valve 4 to one unloading solenoid valve 9. During loading, a predetermined set pressure (for example, 140 Kgf/cm ² -hereinafter simply expressed as 140 k) is output to the hydraulic circuit by the high-pressure pump 1, but when the unloading solenoid valve 9 is operated to unload, the hydraulic pressure is The output to the circuit becomes zero. Therefore, not only when the machine is operated automatically, but also when it is operated manually, unless all the operating switches are in the neutral position, the predetermined set pressure (140k) will always be output to the hydraulic circuit. However, in reality, high voltage (eg 140k) is often not required when operating manually, resulting in unnecessary power consumption.

<Problems to be solved by the invention> The present invention was made in view of these conventional drawbacks, and the set pressure required for manual operation can be varied steplessly from zero to high pressure (for example, 140k). It is an object of the present invention to provide a hydraulic pressure setting circuit for a hydraulic circuit that can be used as a hydraulic circuit, and as a result, there is no need for wasteful power consumption.

<Means for solving the problem> As a means for solving the problem, the oil pressure setting circuit of the present invention connects a high-pressure pump unloading solenoid valve to the high-pressure pump relief valve, and also connects the high-pressure pump relief valve to the high-pressure pump unloading solenoid valve. It is characterized by a relief valve connected in parallel to reduce the output of the high-pressure pump to a predetermined pressure.

<Function> The pressure of the high-pressure pump can be arbitrarily set from zero to high pressure (for example, 140k) by the function of the relief valve connected in parallel with the high-pressure pump unloading solenoid valve to the high-pressure pump relief valve.

<Example> Hereinafter, an example of implementing the present invention will be described based on the drawings.

Basically, like a conventional oil pressure setting circuit, there is a high pressure pump 1 to output a predetermined pressure (for example, 140k) to the hydraulic circuit, a low pressure pump 2 to assist the high pressure pump 1, and a high pressure pump for the high pressure pump. It is composed of a relief valve 3 and a relief valve 4 for a low pressure pump.

And, in the relief valve 4 for the low pressure pump,
For example, when high pressure is not required during manual or automatic operation (for example, during operations other than mold clamping in a die-casting machine or filling oil into an accumulator), the output of the low-pressure pump 2 is unloaded to zero. A solenoid valve 5 for unloading is connected, while a relief valve 3 for the high pressure pump is connected.
An unloading solenoid valve 6 for unloading the output of the high-pressure pump 1 to zero is connected thereto, and a relief valve 7 for reducing the output of the high-pressure pump 1 to a predetermined pressure is connected thereto. This relief valve 7 is connected in parallel to the high-pressure pump relief valve 3 and the high-pressure pump unloading solenoid valve 6 to reduce and maintain the output of the high-pressure pump 1 to a predetermined pressure (for example, 70 k). In the figure, 8 is a solenoid valve for operating the relief valve 7.

<Effects of the invention> Since the invention is configured in this way, the high-pressure pump and low-pressure pump can each be unloaded independently, so the output of the low-pressure pump can be reduced even during manual operation or automatic operation when high pressure is not required. At the same time, the output of the high-pressure pump can be set arbitrarily from zero to high pressure (for example, 140k) using the relief valve 7, thereby reducing unnecessary power consumption. This will allow you to drive more economically.

Therefore, the intended purpose can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram showing an example of implementing the present invention.
FIG. 2 is a hydraulic circuit diagram showing an example of engagement. In the figure, 1 is a high-pressure pump, 2 is a low-pressure pump, 3 is a relief valve for the high-pressure pump, 6 is a solenoid valve for unloading the high-pressure pump, and 7 is a relief valve.

Claims (1)

[Scope of utility model registration request] A hydraulic circuit characterized in that a high-pressure pump unloading solenoid valve is connected to a high-pressure pump relief valve, and a relief valve for reducing the output of the high-pressure pump to a predetermined pressure is connected in parallel with the solenoid valve. Hydraulic setting circuit.