The electro-liquid commutation valve of the planar grinding machine consists of a pilot valve electromagnetic spool valve and a main valve hydraulic valve. This system is switched to switch control oil passage through a planar grinding machine lead. The direction of the oil flow of the oil passage does not change. The reversal valve is always held at one end, the main oil direction is not changed, and the working table can always move forward. Once the control oil is switched in the direction, the main valve body moves to another work orientation according to the speed of prior design, the main oil road direction is changed, and the work station also reverses the movement, avoiding the reversing \u0026 # 39; dead point \u0026 # 39 ;. In this way, the kinetic energy of the highly inertia can be consumed by saving the effect to heat energy, and the controlled oil port of the electro-hydraulic replacement valve main valve is adjustable, the reversal time ΔT can extend. It can effectively reduce the commutation impact, so this commutation method is at a long time in the dominant position. However, its commutation parameters can only be scheduled in advance, and cannot be changed according to the changes of the working conditions. This is impossible to complete the reversing of the message on the system constant changes. Cooperation Zhigong Control Curve. The planar grinding machine uses the hydraulic transmission commutation system of the electro-hydraulic proportional valve. Completed with automatic reduction of flow to fall speed, the end of the intelligent control-type commutation system, and the conditions change can be completed in the case of working conditions. This hydraulic transmission commutation system ends excellent intelligent control over the output displacement or speed, so that the commutation process has a certain controllability, thereby having a wide range of applications.