What is the explanation of the back pressure principle of hydraulic motors?

The hydraulic motor should be connected in series, so that the reverse torque can be completed, which should be able to directly connect the oil return to the B port for the relief valve. If the air pressure is more than the initial value of the relief valve, the oil can be returned and the reserve pressure will be generated. Reserve pressure refers to the air pressure of the oil return port of the hydraulic motor, mainly on the motor with an integrated leakage channel, and the internal leakage channel is connected to the return oil, so the reserve pressure can be the air pressure of the oil discharge port. When the external five-star hydraulic motor is running smoothly, the backup pressure enables the motor to confirm that the motor is filled with hydraulic oil when it is running stably, so that most of the components in the motor begin to be fully lubricated. Therefore, the hydraulic motor back pressure to have a certain reserve pressure value, the reserve pressure value is only to confirm the motor in the no-load stable operation of the minimum output air pressure, the reserve pressure value should not be large, according to the torque of the inner five-star hydraulic motor and its inlet and outlet pressure difference is proportional to the relationship, in the inlet air pressure is certain, when the reserve pressure enhancement will make the hydraulic motor inlet and outlet pressure difference smaller, so the motor flip is boring. Under the same circumstances, its oil return reserve pressure should be 0.5MPa~1.5MPa. If the oil return pressure of the cycloid motor is too large or too small, it is easy to damage the motor and shorten the service life of the motor. Therefore, the oil return reserve pressure of the cycloid motor must not be less than 0.5MPa, Z should not be more than 5MPa, and more than 5MPa should be connected to the leakage pipe. However, if the back pressure of the radial plunger hydraulic motor is like this, there should be sufficient backup pressure to ensure that all the plungers of the motor can be attached to the stator ring of the motor