If the cutting machine hydraulic system seal is not good, may not allow external leakage, leakage of oil will pollute the environment;Air may enter into the oil suction chamber, affecting the working performance of the hydraulic pump and the movement stability of the hydraulic executive elements (crawling), when the leakage is serious, the system volume efficiency is too low, or even the working pressure cannot reach the required value;If oversealing, although can prevent leakage, but will cause severe wear of the sealing part, shorten the service life of the seal, increase the friction resistance of the movement of the hydraulic components, reduce the mechanical efficiency of the system.
Type 0 seal ring is generally made of oil-resistant rubber, its cross section is circular, it has a good sealing performance, inside and outside and the end face can play a sealing role, compact structure, small friction resistance of moving parts, easy to manufacture, convenient installation and disassembly, low cost, in the hydraulic system has been widely used.
Protect the hydraulic cutting machine hydraulic pump from the damage of large - size mechanical impurities, and do not affect the suction of the pump.Another common surface type filter is the wire-gap filter as shown in figure 5-7b. It is a cylinder wound by fine metal wire (d=0.4mm) and relies on the gap between the screw wires to retain impurities in the oil. It is also a coarse filter.When it is installed in the oil inlet of the hydraulic pump, the resistance loss is about 0.02mpa, and the filtration accuracy is about 0.08-0.1mm.The resistance loss of the wire-gap filter installed in the low-pressure pipeline of oil return is slightly greater than that of the former, about 0.07-0.35mpa, and the filtration accuracy is also better, about 0.03-0.05mm. In the actual selection process, we should pay attention to its applicable position.
Air dryer is to absorb and remove compressed air moisture and part of the oil and impurities, so that the wet air into dry air device.The compressed air output from the compressor can meet the requirements of general pneumatic system after the initial purification of the cooler, oil remover and gas storage tank.But some precision machinery, instruments and other devices can not meet the requirements.For this reason, further purification is needed. In order to prevent the moisture content in the gas after preliminary purification from rusting precision machinery and instruments, + should be dried and refined.
To act as an emergency source of power to safely complete a working cycle in the event of hydraulic failure, pump shutdown, or power failure, as for a ship's hydraulic rudder.
Maintain the system at a necessary high pressure over a long period of time without having to start the pump to prevent oil overheating to reduce pump wear and save energy.
Maintenance system pressure: to replenish hydraulic system leakage, or for a long period of hydraulic pump operation to maintain constant pressure equipment.
Drive secondary circuit: the hydraulic energy of the accumulator can be used to drive secondary circuit when the main circuit is stopped due to adjustment, maintenance and other reasons.
When no current signal input, torque motor no torque output, with the armature 5 fixed baffle 9 in the middle position, the main slide valve spool is also in the middle (zero) position.The oil output from the hydraulic pump enters the valve port of the main slide valve with pressure ps. Because the valve port is closed at both ends of the spool, the oil cannot enter port A and port B. However, it is channeled to nozzle 8 and 7 through the throttle hole 10 and 13 respectively.Because the baffle is in the middle, the gap between the two nozzles and the baffle is equal, so the liquid resistance flowing through the nozzle is equal, then the pressure p1 in front of the nozzle is equal to p2, the pressure at both ends of the main slide valve spool is equal, and the spool is in the middle.