The commutation method and commutation control parameters in the system have a decisive effect on the commutation impact. The surface grinder uses hydraulic transmission. Planning a new hydraulic reversing system is very important. From the perspective of reversing methods and control strategies, we will discuss many hydraulic transmission reversing methods of surface grinders.
1. The reversing method of selecting the stroke reversing valve: a pull rod is connected to the reversing valve core to change the direction of the stroke reversing valve. Use the stroke stop on the workbench to advance the pull rod to realize automatic reversing. When the worktable of the surface grinder moves slowly, when the reversing valve reaches the middle position, regardless of whether the left and right chambers of the hydraulic cylinder are both filled with pressure oil, or both return oil, or both are closed, at this time, the two chambers of the hydraulic cylinder If there is no hydraulic pressure, it will stop the movement of the worktable. Therefore, the reversing valve cannot reach the other end, and the so-called “dead point” appears.
2. The reversing method of the electromagnetic reversing valve: the travel stop is pushed by the travel switch to announce the reversing signal, and the travel reversing valve is changed to the reversing method of the electromagnetic reversing valve. The electromagnet is used to push the spool valve to reverse, which can avoid the “dead point”; but it is a kind of on-off hydraulic valve that opens or closes instantaneously according to instructions, that is, instantaneously connects or blocks the oil return channel. Such a hydraulic reversing system is There will be a big impact when changing directions.
3. The reversing method of the electro-hydraulic directional valve: the pilot valve is not switched forward, and the electro-hydraulic directional valve is used to replace the electromagnetic reversing valve to constitute a new reversing method. The electro-hydraulic directional valve is composed of a pilot valve solenoid spool valve and a main valve hydraulic spool valve. Once the control oil circuit switches the direction, the main valve spool of the surface grinder moves to another working position according to the pre-set speed. The main oil circuit direction changes, the worktable also reverses movement, avoiding the “dead point” “.