It is well known that the disadvantages of hydraulic transmission, such as low efficiency, high noise, high cost, leakage and environmental pollution, reduce its competitiveness. These disadvantages obviously do not adapt to the social and engineering needs of environmental protection, energy saving and sustainable development. The electric transmission technology has the advantages of environmental protection, energy saving, long-distance power transmission, etc., in line with the development trend of modern industry, especially ac servo motor, frequency conversion technology has made great progress, in the range of medium and low power power transmission technology to form a threatening challenge to the hydraulic transmission technology.
Hydraulic transmission, as a power transmission device, includes the process of converting from mechanical energy to hydraulic energy, transmission and re-conversion from hydraulic energy to mechanical energy and external work. Therefore, energy consumption inevitably exists in the process of energy conversion and transmission. The total efficiency of the system is the product of the efficiency of the hydraulic pump station, the system transmission efficiency and the efficiency of the actuator. The general efficiency of hydraulic transmission is 50 to 70 percent, and the efficiency of some walking machinery is less than 10 percent. Therefore, improving efficiency is an important problem solved by hydraulic technology, but also an effective measure to improve its competitiveness.
First of all, the hydraulic pump variable adjustment device adopts pressure compensation, load sensing system, so that it has flow adaptive control and load pressure automatic compensation function, so that the efficiency can be increased by more than 30 percent; Such as the proportional pressure flow control variable plunger pump produced by a Japanese company for plastic injection machine, can save energy up to.
The energy regeneration control is realized by using the secondary regulation technology, such as the reuse of the excess energy of the excavator's lifting arm and the rotary braking energy. Secondly, the volume efficiency of hydraulic pumps and motors is relatively low in the use of small displacement, which limits the working range of their displacement.
In order to improve the total efficiency of hydraulic pumps and motors and expand the working range of their displacement, it is necessary to develop new sealing and friction reducing materials and improve the design method of oil film lubrication between relative moving parts, so as to effectively reduce the lubrication leakage loss and improve the volume efficiency.
Adopt advanced design concept to minimize power loss during energy transmission. For example: using cartridge valve to replace the conventional cylindrical slide valve to reduce valve pressure drop loss and improve performance; Integrated components and systems designed to reduce line pressure losses; Design pipe diameter and pipe layout properly to reduce pipe pressure loss.
Improving efficiency is an important problem solved by hydraulic technology, and also an effective measure to improve its competitiveness. The level of hydraulic transmission technology has become an important symbol of a country's industrial development level. We should try our best to improve the efficiency of hydraulic transmission and adapt to the development of the world.
