Research On Hvdraulic Compensating System For Ram’s Slide Guide Of NC Machine

Since the ram on machine tool can cause micro gap when sliding, we invent this hydraulic compensation system in order to avoid the problems caused by the micro gap, like: low machining accuracy, tool vibration and low quality of the machining surface.Hydraulic compensation system is composed of the backlash compensation actuators, hydraulic control system and electrical system. The backlash compensation actuator is shaped into thin-walled circle, and can make up for the gap by its elastic material. To accurately pressurize the actuator, a special overflow valve or a closed reciprocating precision pressurized system is used by hydraulic control system. And the electrical system convert Z-axis signal to analog signal which is used for control proportional valve.In order to design the backlash compensation actuator, we adopt thin-walled pressure structure theory to calculate the bending, and use ANSYS software to analyze the strain and stress. After testing this system in laboratory, we summarize the displacement and pressure output characteristics.This system can provide pressure figure according to Z-axis gap signal without affecting the normal work of the main oil station, and at the same time, it can reduce the work branch overflow waste; the control signal required by the proportional valve can be transmitted by Z-axis signal.Lots of test results reveal that the displacement output characteristics are controllable, compensation output is accurate and the displacement output is linear with oil pressure. All the above shows that this system meets the requirement of the gap compensation and can effectively improve the ram’s contacting stiffness as well as the surface quality.