Anyone with a little mechanical knowledge knows that energy can be converted to each other, and it is best to apply this knowledge to the hydraulic system to explain the power loss of the hydraulic system. On the one hand, the power of the hydraulic system will cause energy loss and make the system On the other hand, this part of the energy lost will be converted into heat energy, which will increase the temperature of the hydraulic oil, deteriorate the oil, and cause hydraulic equipment to malfunction. Therefore, when designing a hydraulic system, under the premise of meeting the requirements of use, full consideration should be given to reducing the power loss of the system.
First, from the perspective of the power source—pumps, considering the diversification of actuator working conditions, sometimes the system requires large flow and low pressure; sometimes it requires small flow and high pressure. Therefore, it is appropriate to choose a pressure-limiting variable pump, because the flow rate of this type of pump changes with the change of system pressure. When the system pressure decreases, the flow rate is relatively large, which can satisfy the fast stroke of the actuator. When the system pressure increases, the flow rate decreases accordingly, which can meet 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.
Second, when hydraulic oil flows through various types of hydraulic valves, there will inevitably be pressure loss and flow loss, and this part of the energy loss accounts for a large proportion of the total energy loss. Therefore, reasonable selection of hydraulics and adjustment of pressure valve pressure are also an important aspect of reducing power loss. The flow valve is selected according to the flow adjustment range in the system and 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.
Third, if the actuator has a speed regulation requirement, when selecting a speed regulation circuit, it is necessary to meet the speed regulation requirement while minimizing power loss. The common speed control circuits mainly include: throttling speed control circuit, volume speed control circuit, volume throttle speed control circuit. Among them, the power loss of the throttle speed control loop is large, and the low speed stability is good. The volumetric speed control circuit has neither overflow loss nor throttling loss, which has high efficiency but poor low-speed stability. If you want to meet the requirements of both aspects at the same time, you can use a differential pressure variable pump and a throttle valve to form a volume throttling speed control loop, and make the pressure difference between the two ends of the throttle valve as small as possible to reduce pressure loss.
Fourth, choose hydraulic oil reasonably. When the hydraulic oil flows in the pipeline, it will exhibit viscosity, and when the viscosity is too high, it will generate greater internal friction, causing the oil to heat up, and at the same time increase the resistance when the oil flows. When the viscosity is too low, it is easy to cause leakage, which will reduce the volumetric efficiency of the system. Therefore, generally choose the oil with suitable viscosity and good viscosity-temperature characteristics. In addition, when the oil flows in the pipeline, there are pressure losses and local pressure losses along the way. Therefore, when designing the pipeline, try to shorten the pipeline as much as possible while reducing the number of bends.
The above are the points proposed to avoid the power loss of the hydraulic system. However, there are many factors that affect the power loss of the hydraulic system. Therefore, when a hydraulic system is specifically designed, other requirements must be considered comprehensively.