Explain the working principle of hydraulic transmission

: (1) the working principle of hydraulic transmission as shown in the diagram of the hydraulic transmission of the grinding machine table schematic, hydraulic pump 3 driven by the motor, from the tank 1 in the oil suction, and then has the pressure energy of the oil transported to the pipeline, the oil through the throttle valve 4 and pipeline flow to the directional valve 6, directional valve 6 spool has a different working position (three working positions in the figure), so the access is different when the spool is in the middle position, the spool P. A, B. T do not communicate with each other. When the spool is in the middle position, the valve ports P. A, B. T do not communicate with each other. To the hydraulic cylinder is blocked, the hydraulic cylinder does not pass the pressure oil, so the table stops not moving; if the spool push to the right (right end of the working position), then the valve port P and A, B and T are connected, the pressure oil through the P port flows into the reversing valve 6, through the A port into the hydraulic cylinder 8 of the left cavity, the piston 9 in the left cavity of the cylinder under the pressure of the oil driven by the cylinder to drive the table to the right to move 10; the right cavity of the hydraulic cylinder oil through the reversing valve 6 b port flows into the reversing valve 6, the piston 9 in the cylinder to move to the right. The oil in the right chamber of the hydraulic cylinder flows into the reversing valve 6 through the b port, and flows back to the tank 1 through the return port T; if the spool of the reversing valve 6 is pushed to the left (left end working position), the piston drives the worktable to move to the left; therefore, the reversing valve 6 works in different positions, you can constantly change the pressure oil path, so that the hydraulic cylinder is constantly reversed to achieve the reciprocating motion of the worktable required. According to the different processing requirements, the table's moving speed can be adjusted through the throttle valve 4, the use of changing the size of the throttle valve opening to adjust the flow rate through the throttle valve, in order to control the table's movement speed. Table movement, due to different working conditions, to overcome different resistance, different resistance are overcome by the hydraulic pump output oil pressure energy, the system pressure can be adjusted through the relief valve 5. When the oil pressure in the system rises to the tip higher than the regulating pressure of the relief valve, the steel ball on the relief valve is topped off, the oil through the relief valve back to the tank. At this time, the oil pressure no longer rises, maintain the fixed value. In order to maintain the oil Pu clean, set up a filter, the oil in the dirt impurities removed, so that the system works properly. In short, the working principle of hydraulic transmission is the use of liquid pressure energy to transfer power; the use of executive elements will be converted to mechanical energy of the liquid pressure energy, drive the movement of working parts. Liquid positive system work, the fluid pressure, flow, direction of control and regulation to meet the working parts in the force, speed and direction of the requirements. (2) the composition of the hydraulic system a complete hydraulic system mainly consists of the following five parts; 1) power unit It supplies the hydraulic system pressure, and the output of the motor's mechanical energy is converted to the oil pressure energy, thus promoting the entire hydraulic system. Such as the figure in the hydraulic pump 3 is the power unit, the oil from the tank 1 suction, and then transported to the system. 2) the implementation of the components; it includes hydraulic cylinders and hydraulic motors, used to convert the pressure of the liquid energy into mechanical energy to drive the movement of the working parts; Figure 8 is a hydraulic cylinder, driven by the pressure of the oil to drive the grinding machine table to do linear motion; 3) control and adjustment devices including a variety of valves, such as pressure, flow, valves, and directional valves. And directional valves, etc.. Used to control the hydraulic system of liquid pressure, flow (flow rate), and the direction of the liquid flow to ensure that the executive element to complete the expected work movement. Figure 5 is a relief valve, used to control the system pressure; 4 is a throttle valve, used to wither into the flow of hydraulic cylinders, thereby controlling the table's movement speed; 6 is a directional valve, used to change the pressure oil path, so that the hydraulic cylinder reversal, the realization of the reciprocating motion of the table. 4) Auxiliary devices refers to a variety of fittings, tubing, oil tanks, over-set out and the direction of liquid flow. Oil tank, set forth and pressure gauge. They play a connection, oil storage, filtration, storage pressure and measurement of oil pressure and other auxiliary role to ensure that the hydraulic system is reliable. Stable, lasting work. Figure 2 for the net filter. The role of filtration of oil; 1) for the tank, used to store oil and oil heat dissipation. 5) working medium refers to the hydraulic system, bear pressure and transfer pressure of the fluid The most basic principle is that all parts of the liquid in the transfer of pressure can keep the pressure unchanged but the direction of change! Coupled with the relationship between pressure and pressure F = PS, the larger the pressurized area, the greater the pressure.