Hydraulic maintenance The working principle of hydraulic transmission can be explained by the working principle of a hydraulic jack.
It is the working principle diagram of the hydraulic jack. The big oil cylinder 9 and the big piston 8 form a lifting hydraulic cylinder . The lever lever l, the small oil cylinder 2, the small piston 3, the check valves 4 and 7 form a manual hydraulic pump . For example, if the handle is lifted to move the small piston upward, the volume of the oil chamber at the lower end of the small piston increases to form a partial vacuum. At this time, the check valve 4 opens and sucks oil from the oil tank 12 through the oil suction pipe 5; At this time, the pressure in the lower chamber of the small piston increases, the check valve 4 is closed, and the check valve 7 is opened. The oil in the lower chamber is input into the lower chamber of the lifting cylinder 9 through the pipeline 6, forcing the large piston 8 to move upward and lift the weight. . When the handle is lifted again to suck oil, the check valve 7 is automatically closed, so that the oil cannot flow backward, thereby ensuring that the heavy objects will not fall by themselves. By constantly reciprocating the handle, the hydraulic oil can be continuously fed into the lower cavity of the lifting cylinder, so that the heavy objects can be gradually raised. If the shut-off valve 11 is opened, the oil in the lower chamber of the lifting cylinder flows back to the fuel tank through the pipe 10 and the shut-off valve 11 and the weight moves downward. This is how the hydraulic jack works.
A lever handle does not have a small oil cylinder; 3 a small piston; 4, 7 a one-way valve; 5 a suction pipe; 6, 1 silo and a pipeline; 8 a large piston; 9-a large oil cylinder; U a stop valve; 12 a tank
Through the analysis of the working process of the hydraulic jack above, we can preliminary understand the basic working principle of hydraulic transmission: Hydraulic transmission is a transmission method that uses pressure oil as a medium to transfer motion and power. When the lever is depressed, the small oil cylinder 2 outputs pressure oil, which is the pressure energy that converts mechanical energy into oil. The pressure oil passes through the pipeline 6 and the check valve 7 and pushes the large piston 8 to lift the heavy object. This is to convert the pressure energy of the oil into mechanical energy. The lifting speed of the large piston 8 depends on the amount of oil flowing into the large oil cylinder 9 per unit time. It can be seen that hydraulic transmission is a conversion process of different energy. Its working principle is as follows: After the hydraulic pump is driven by the electric motor, it sucks oil from the oil tank. The oil enters the hydraulic pump through the oil filter. The oil in the pump cavity goes from the low pressure of the population to the high pressure of the pump outlet. The piston moves the table to the right. At this time, the oil in the right cavity of the hydraulic cylinder is drained back to the tank via the diverter valve and the return pipe 6.
Shown is a hydraulic drive system for driving a machine tool table. It consists of a fuel tank 19, an oil filter 18, a hydraulic pump 17, an overflow valve 13, a reversing valve 4, a throttle valve 7, an on-off valve 1 and a hydraulic cylinder 2. And oil pipes, pipe joints, etc. that connect these components.
The moving speed of the table is adjusted by the throttle valve. When the throttle valve is opened, the amount of oil entering the hydraulic cylinder increases and the moving speed of the table increases; when the throttle valve is closed, the amount of oil entering the hydraulic cylinder decreases, and the moving speed of the table decreases. In order to overcome the various resistances encountered when moving the table, the hydraulic cylinder must generate a sufficient thrust, which is "2". Hydraulic repair