Double hydraulic pump, the same transmission shaft driv […]
Double hydraulic pump, the same transmission shaft drives the rotors of two pumps to rotate, which are connected and driven by a motor. The suction port of the pump is public, and the pressure ports are separated. The two flows output by the pump can be used separately or in parallel.
Hydraulic transmission is a kind of hydraulic component that provides pressurized liquid and a kind of pump. Its function is to convert the mechanical energy of power machine (such as motor and internal combustion engine) into the pressure energy of liquid. The working principle of single plunger pump is shown in the figure.
The cam is driven by an electric motor. When the cam pushes the plunger to move upward, the sealing volume formed by the plunger and the cylinder decreases, and the oil is extruded from the sealing volume and discharged to the required place through the one-way valve.
When the cam rotates to the falling part of the curve, the spring forces the plunger downward to form a certain degree of vacuum, and the oil in the oil tank enters the sealing volume under the action of atmospheric pressure. The cam makes the plunger constantly rise and fall, the seal volume periodically decreases and increases, and the pump continuously absorbs and discharges oil.
Hydraulic pump pressure:
The working pressure of hydraulic pump refers to the pressure of oil output (or input) when the pump (or motor) is actually working, which is determined by the external load. Rated pressure refers to the maximum pressure that can operate continuously according to the test standard under normal working conditions.
Its size is limited by the service life. If the rated pressure is exceeded, the service life of the pump (or motor) will be shorter than the designed service life. When the working pressure is greater than the rated pressure, it is called overload.
Working speed refers to the actual rotation speed of the pump (or motor) when it is working. Rated speed refers to the highest speed that can operate normally for a long time under rated pressure.
If the pump works over the rated speed, it will cause insufficient oil absorption, vibration and large noise, and the parts will suffer cavitation damage and reduce the service life. The minimum stable speed refers to the minimum speed allowed by the normal operation of the motor. At this speed, the motor does not creep.
Displacement and flow:
Displacement refers to the volume of discharged (or input) liquid obtained from the change of geometric dimension of the sealing cavity every revolution of the pump (or motor). The common unit is ml / R (ml / revolution).
The displacement can be changed into variable pump (or variable motor) by adjusting, and the displacement can not be changed into fixed pump (or fixed motor).
The actual flow refers to the flow at the outlet (or inlet) when the pump (or motor) is working. Due to the internal leakage of the pump itself, its actual flow is less than the theoretical flow. Because the motor itself also has internal leakage, in order to achieve the specified speed, in order to compensate the leakage, the actual input flow must be greater than the theoretical flow.