In a fixed pump system, the oil supply pressure of the hydraulic pump can be adjusted through a relief valve; in a variable pump system, a safety valve is used to limit the maximum pressure of the system to prevent system overload; if more than two pressures are required in the system: Multi-stage voltage regulating circuit can be used

Classification

Clamping circuit (single stage): used to prevent the oil from flowing back when the main oil line pressure is lower than the set pressure of the pressure reducing valve, and plays a short-term pressure maintaining role.

Secondary pressure reducing circuit

Single acting booster circuit

Two-way booster circuit

method

type

Pressure-holding circuit using an accumulator: The length of the pressure-holding time depends on the capacity of the accumulator. Adjusting the working range of the pressure relay can adjust the maximum and minimum values ​​of the pressure in the cylinder.

Automatic oil replenishment pressure maintaining circuit

Movement speed of hydraulic cylinder

Hydraulic motor speed

Throttle speed regulating circuit: For the fixed pump oil supply system, use the flow control valve (Adjustment A) to regulate the speed

Volumetric speed control loop: For a variable pump (motor) system, the speed is adjusted by changing the displacement of the variable pump or variable hydraulic motor.

Volumetric throttling speed regulation (joint speed regulation) circuit: using variable pump and flow control valve to regulate speed

Hydraulic cylinder differential connection circuit: widely used in the rapid movement of hydraulic power slides of combined machine tools and other mechanical equipment

Rapid motion circuit using accumulator: It is suitable for occasions that require large flow in a short period of time, and a small flow hydraulic pump can be used to make the hydraulic cylinder obtain a larger movement speed. It should be noted that within a working cycle of the hydraulic cylinder, There must be sufficient downtime to allow the hydraulic accumulator to be filled with liquid

Double-pump oil supply circuit: often used in situations where the actuator requires fast feed and slow feed with a large speed difference.

Rapid motion circuit using speed-increasing cylinder: commonly used in hydraulic press systems

Advantages: The fast and slow speed switching process is relatively smooth, and the position of the switching point is relatively accurate.

Disadvantages: The installation position with a wide stroke cannot be arranged arbitrarily, and the pipeline connection is relatively complicated.

single speed regulating valve

Speed ​​regulating valve in parallel

Speed ​​regulating valve in series

Features: The work is reliable, but once the action sequence is determined, it is difficult to change it.

Application: Suitable for hydraulic systems of machining equipment where the action sequence and stroke do not need to be changed

Features: It is convenient to adjust the stroke. Changing the electrical control circuit can change the action sequence of the hydraulic cylinder.

Application: Suitable for situations where the itinerary and sequence of cyclic actions often need to be changed

Features: sensitive action, easy installation and connection, reliability depends to a large extent on the performance of the sequence valve and its pressure adjustment value

Application: Suitable for occasions where the number of hydraulic cylinders is small and the load changes little.