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本文仅就国外近十年来液压元件和系统的新产品新结构发展趋势加以回顾液压元件和辅件总的发展趋势性能提高主要表现在液压泵和与之配套的阀和软管等辅件的额定压力提高。例如斜盘式轴向柱塞泵的额定压力从350bar 提高到420bar,齿轮泵从210bar 提高到300bar 甚至320bar,其重量/功率比由0.8减小到0.5。日本油研公司在70年代中期试制出压力为400bar 的小型叶片泵并一度展出,但只有一种规格,而且要用特种耐磨油,实际应用价值不大,其后未见发展。故叶片泵的压力水平仍停滞在210bar上下。其次是液压泵的噪声降低。不过这只限于个别厂家的个别品种,并非全面开花。况且在组成闭式系统的轴向柱塞泵上,由于要求双向变量,在泵的结构上就难以照顾到互有矛盾的性能参数要求。阀的“小型化”的含义是性能参数相同而阀的体积较小,反过来说,即指和原型阀的体积相同或接近的阀,其额定流量增大。从这一角度考虑,也可以说是提高了原型阀的性能参数。一般辅件的额定压力和流量能和泵等配套,但软管就有一定困难。目前,国外还只有少数厂家可以提供350bar 级φ50通径的高压软管。有6层钢丝缠绕式和4层钢丝缠绕式以及2层钢丝缠绕相间加上两层钢丝编织
This article reviews only the development trend of new products and new structures of hydraulic components and systems in foreign countries in recent ten years. The overall development trend of hydraulic components and accessories is mainly reflected in the improvement of the performance of hydraulic pumps and their accessory valves and hoses Pressure increased. For example, the rated pressure of the swash plate axial piston pump is increased from 350 bar to 420 bar, the gear pump is increased from 210 bar to 300 bar or even 320 bar, and its weight / power ratio is reduced from 0.8 to 0.5. Japan oil research company in the mid-70s to produce a pressure of 400bar small vane pump and once exhibited, but only one specification, but also to use special wear-resistant oil, practical value is not, then no development. Therefore, the pressure level of the vane pump still stagnates at 210bar. Followed by the hydraulic pump noise reduction. However, this is limited to individual species of individual manufacturers, not fully blossom. Moreover, axial piston pumps that form a closed system require difficult bi-directional performance parameters due to the requirement of bidirectional variables. The meaning of the “miniaturization” of the valve is that the performance parameters are the same and the valve size is small. Conversely, the nominal flow rate of the valve with the same or similar valve size as the prototype valve increases. From this perspective, it can be said that the prototype valve to improve the performance parameters. General accessories rated pressure and flow and pumps and other ancillary, but the hose there is a certain difficulty. At present, only a few foreign manufacturers can provide 350bar-class φ50 diameter high-pressure hose. There are 6 layers of wire wound and 4 layers of wire wound and 2 layers of wire wound plus two layers of wire braid