我厂的Л3-34型外圆磨床和3A-240型内圆磨床的结构比较落后,精度保持性差,刚性低,性能不稳定;机床的液压操纵系统及其元件都比较落后,泄漏也比较严重。为此,我们于1977年先后采用国产液压元件对这两种老设备的液压系统及控制装置进行了改造与改装。现以Л3-34型外圆磨床为例,将 The structure of Л3-34 cylindrical grinding machine and 3A-240 type internal grinder in our factory is relatively backward, the precision is poorly maintained, the rigidity is low and the performance is unstable. The hydraulic control system and its components of the machine tool are relatively backward and the leakage is serious . To this end, we have in 1977 adopted domestic hydraulic components of these two old equipment, hydraulic systems and control devices were modified and modified. Now Л3-34 type cylindrical grinding machine, for example