Load sensing heat dissipation braking variable system of loading machine

The invention discloses a load sensing heat dissipation braking variable system of a loading machine. The load sensing heat dissipation braking variable system of the loading machine is characterized by mainly being composed of a variable displacement piston pump, a parking braking valve, a first energy accumulator, a second energy accumulator, a braking valve and a load sensing prefilling valve in an integral mode. A pressure oil port of the load sensing prefilling valve is connected with a pressure oil port of the variable displacement piston pump. Pressure oil is provided for the energy accumulators and working devices in a prefilling state. Pressure oil used for controlling a limit switch (LS) is output to control the variable displacement piston pump to provide flow required by a system. Priority of prefilling is maintained. A temperature signal of the heat dissipation system is converted into an electric signal to control an electric proportional pressure reducing valve in the load sensing prefilling valve, and the prefillig is prior. The variable displacement piston pump is a load sensing plunger pump comprising an LS control valve and a pressure stop valve and is capable of controlling a variable pump tilting tray to provide the flow required by the system. The load sensing heat dissipation braking variable system of the loading machine has the advantages of being easy to realize, saving in energy, and suitable for being used on loading machines of various tonnage.