The power loss of the hydraulic system will cause energy loss on the one hand, and the total efficiency of the system will decrease. On the other hand, this part of the lost energy will be converted into heat energy, causing the temperature of the hydraulic oil to rise and the oil to deteriorate. The hydraulic equipment has failed. Therefore, when designing the hydraulic system, the power loss of the system should be fully considered under the premise of meeting the requirements of use.
First of all, from the perspective of the power source-pump, considering the diversification of the working conditions of the actuator, sometimes the system requires large flow, low pressure; sometimes it requires small flow and high pressure. Therefore, it is advisable to choose a pressure-limiting variable displacement pump because the flow rate of this type of pump varies with the pressure of the system. When the system pressure is reduced, the flow rate is relatively large, which can satisfy the fast stroke of the actuator. When the system pressure is increased, the flow rate is correspondingly reduced, which can satisfy the working stroke of the actuator. This can not only meet the working requirements of the actuator, but also make the power consumption more reasonable.
Secondly, if the actuator has the requirements of speed regulation, then when selecting the speed control loop, it is necessary to meet the requirements of speed regulation and minimize the power loss. Common speed control loops mainly include: throttle speed control loop, volume speed control loop, and volume throttle speed control loop. Among them, the throttling speed control circuit has large power loss and good low speed stability. The volumetric speed control circuit has neither overflow loss nor throttling loss, high efficiency, but low speed stability. If both requirements are met at the same time, a volumetric throttle circuit composed of a differential pressure variable pump and a throttle valve may be employed, and the pressure difference across the throttle valve is made as small as possible to reduce the pressure loss.
Third, there is inevitably pressure loss and flow loss when hydraulic oil flows through various types of hydraulic valves. This part of the energy loss accounts for a large proportion of total energy loss. Therefore, the rational selection of the hydraulic device and the adjustment of the pressure of the pressure valve are also an important aspect of reducing the power loss. The flow valve is selected according to the flow regulation range in the system and ensures that its minimum stable flow can meet the requirements of use. The pressure of the pressure valve should be as low as possible when the hydraulic equipment is working normally.
Fourth, rational selection of hydraulic oil. When the hydraulic oil flows in the pipeline, it will exhibit viscosity, and when the viscosity is too high, it will generate a large internal friction, which will cause the oil to heat up and increase the resistance when the oil flows. When the viscosity is too low, it is easy to cause leakage, which will reduce the system volumetric efficiency. Therefore, oils with suitable viscosity and good viscosity-temperature characteristics are generally selected. In addition, when the oil flows in the pipeline, there is also a pressure loss along the process and a partial pressure loss, so the pipeline is designed to be shortened as much as possible while reducing the bend.
