Failure phenomenon of the machining center: During the working process of the machine tool, the mechanically shifted sliding gear in the spindle box is automatically disengaged, and the spindle stops.
Analysis and processing process:
The main transmission of the transmission gear uses a hydraulic cylinder to drive the sliding gear to change the speed, and the hydraulic cylinder also locks the sliding gear. The shift and slip gears are automatically disengaged, mainly due to pressure changes in the hydraulic cylinder.
The O-shaped three-position four-way directional valve that controls the hydraulic cylinder cannot be closed when it is in the middle position, and the oil passages of the front and rear chambers of the hydraulic cylinder are leaking. The movement gradually disengages the slip gear, causing the spindle to stop.
After replacing the new three-position four-way reversing valve, the problem can be solved; or the control method is changed, and the two-position four-way is adopted to keep the pressure chamber of the hydraulic cylinder at all times.