Four-blade round nose knife

The utility model relates to the technical field of cutting tools, in particular to a four-blade round nose knife which is characterized in that cold air is blown to a four-blade round nose knife main body through fan blades, so that the temperature of the four-blade round nose knife main body is prevented from being too high when the four-blade round nose knife main body is processed, and the heat dissipation rate and the heat dissipation effect of the four-blade round nose knife main body are improved; comprising a four-blade round nose knife body, a screw rod, a heat dissipation rod, a mounting block, a mounting assembly, a fixing ring, a first gear, two sets of second gears, two sets of rotating shafts and multiple sets of fan blades, the screw rod is fixed to the bottom end of the four-blade round nose knife body, a threaded groove is formed in the top end of the heat dissipation rod, the screw rod is in threaded connection with the heat dissipation rod, and the mounting block is fixed to the bottom end