中英文文献中英文翻译液压与气压传动的特点及发展应用概况.doc

The Features and Development History and Application of Hydraulic and Pneumatic Transmission 1. The advantages of hydraulic transmission 1) A hydraulic system can produce higher power than electrical equipment under the same volume. The hydraulic equipment system has smaller volume, light, high power consistency and compact configuration at a given power. The volume and weight of a hydraulic motor are about 12% of an electric motor. 2) Hydraulic equipment has a good working stability. It is because of light , less inertia , quick response : the hydraulic equipment can realize celerity start-up , brake and frequent change in motion direction . 3) The hydraulic transmission can reach a wide range of speed regulation (with the range of 1:2000), and the speed can also be regulated during the work processing. 4) The hydraulic transmission can easily realize automation and the pressure; flow rate and the flow direction can be regulated and controlled. If we combine it with electric, electron or pneumatic control systems, a more complex transmission system with remote control can be realized. 5) The hydraulic system can protect from over-load easily, which cannot be done by electricity or machine equipment. 6) Because of standardization, series, and all-purpose application; the hydraulic system is easier in design, fabrication and application. 7) The hydraulic system is easier than machine equipment in doing line motion. 2. The shortages of hydraulic transmission 1) Leak. Oil leaks are inevitable because of the loss in fluid flow resistance. So more energy loss exists in a hydraulic transmission. 2) Working temperature. The working temperature has strong effect on the working property of a hydraulic system because of the viscosity-temperature character of hydraulic oil . It is suitable for working in a proper temperature. 3) Cost. The cost is high because of the needs in high precision fabricate for hydraulic elements. 4) It is difficult to find the reasons of fault. 3