Working principle of Manifold Block hydraulic motor-The specific selection of hydraulic valve
Speaking from the principle of work, the opposite form of hydraulic pump and hydraulic motor can be replaced with each other. However, under normal conditions, the unimproved hydraulic pump should not be used as Manifold block hydraulic motor. This is because considering the elements such as pressure balance and automatic compensation of clearance seal, the structure of the suction and discharge cavity of the hydraulic pump is asymmetric and can only be rotated in both directions. But as a hydraulic motor, it usually requires positive and reverse rotation, and requires symmetrical structure.
1. Vane hydraulic motor due to the effect of pressure oil, the force is not balanced so that the rotor torque. The output torque of the vane hydraulic motor is between the displacement of the hydraulic motor and the inlet and outlet of the hydraulic motor
Specific selection of Manifold Block hydraulic valve
1. Selection of direction control valve
The direction valve should be selected according to the requirements of the system work, such as the requirement that the oil flow can only flow in one direction, not reverse flow, then the one-way valve should be selected; If the actuator is required to complete the forward one back one stop working cycle, three directional valve should be selected; If only two working states are completed, that is, feed and return, two directional valve should be selected to connect or close the oil circuit; Again, such as the executive components to complete the “fast forward → work into → fast back → stop” work cycle or reciprocating frequent movement, usually should be selected to change the direction of oil flow valve. The direction valve can also be selected according to the working state of the system and the characteristics of the valve. For example, the quality of the moving parts is small, the reversing accuracy is not high, and the flow rate is less than 63 L/min. The electromagnetic reversing valve should be selected. If the mass of the moving parts is large, the speed range is large, and the reversing is required to be stable, and the flow rate is greater than 63 L/min, the electro-hydraulic reversing valve with stable reversing and no impact should be selected; If there is a locking loop in the system, the hydraulic control check valve with good sealing performance should be selected, rather than the reversing valve with poor sealing performance.
2. The selection of pressure control valve
The Manifold block pressure control valve controls the pressure of the Manifold block hydraulic system, so it should be selected according to the working state of the hydraulic system, the requirements for pressure and the function of the control valve in the system. For example, in the quantitative pump throttle speed control system, the motion speed of the actuator is controlled by the throttle valve; In order to keep the working pressure of the pump constant, the relief valve should be selected to stabilize the pressure and overflow; In order to prevent system overload, a relief valve can be parallel at the outlet of the pump to protect the safety of the pump and the whole system; If there is a pressure relief circuit in the system, the pressure relief valve must be used to reduce the pressure of the high pressure circuit to low pressure; If pressure is used to control the sequential action of each component in the system, the sequence valve should be used to adjust the pressure of the sequence valve to the required pressure value, so as to control the sequence of action of the component. Pressure relay can also be used to convert the liquid pressure into electrical signals to control the sequential action of each component. If the motion of the actuator is required to be stable, the back pressure valve should be set on the circuit to form a certain oil return resistance, which can greatly improve the motion stability of the actuator. Relief valves, sequence valves, check valves and throttle valves can be used as back pressure valves.
3. Selection of Manifold Block flow control valve
The flow control valve is selected mainly according to the working state of the hydraulic system and the characteristics of the flow control valve to control the speed of the actuator. For example, the speed of the actuator is stable, and does not creep, should choose the speed control valve, in the selection of the specification of the speed control valve, should pay attention to the minimum stable flow of the speed control valve, should meet the minimum speed requirements of the actuator, that is to say, the minimum stable flow of the speed control valve should be less than the minimum flow required by the actuator; If the flow stability requirements are particularly high, or for micro feed, the temperature compensation type speed control valve should be selected.
In short, the choice of Manifold Block hydraulic valve has a great relationship with the success or failure of the system. As a hydraulic designer, we should have a comprehensive understanding of the production situation of hydraulic valves at home and abroad, especially the performance of various hydraulic valves, the replacement and replacement of new and old products. It is also necessary to often go to the use site to understand the working condition of Manifold Block hydraulic valve, only in this way can the correct and reasonable selection of Manifold Block hydraulic valve be achieved.