At present, there are many hydraulic drive commutation methods applied to precision surface grinder. In view of the analysis of common hydraulic drive commutation methods, the following is a simple analysis and comparison. The reversing method using stroke reversing valve The reversing mode and control parameters in the system have a decisive role in reversing impact, and the surface grinder adopts hydraulic transmission. It is urgent to design a new hydraulic reversing system. In the following, the problem of reversing impact of grinder is discussed from the perspective of reversing method and control strategy.

A pull rod is connected to the reversing valve core, so that the stroke reversing valve is used for reversing. Use the travel stop on the workbench to push the pull rod to realize automatic commutation. When the workbench moves slowly, when the reversing valve reaches the middle position, no matter whether the left and right cavities of the hydraulic cylinder are all filled with pressure oil, oil return or closed, at this time, the two cavities of the hydraulic cylinder are not pushed by hydraulic pressure, which will stop the movement of the workbench, so the reversing valve cannot reach the other end, and the so-called "dead point" appears; Jin Jitong suggested that when the workbench moves at a high speed, the stopper pushes the pull rod to change the direction of the reversing valve very quickly, and the pressure in one chamber of the hydraulic cylinder suddenly drops from the working pressure P to 0, while the pressure in the other chamber suddenly rises from 0 to P, which leads to a great reversing impact. At present, this system is widely used in small grinding machines.