US Patent 10000900 Handheld blower having engine cooling flow

A handheld blower includes a housing, the housing including an air inlet and a duct assembly, the duct assembly including a duct, a motor and a fan mounted in the duct, a battery, a handle, and a blowpipe which defines a central axis. Along the direction of the central axis, the area of the flowing cross-section of an air passage at the rear end of the fan adjacent to the air inlet is larger than that of the flowing cross-section of an air outlet of the blowpipe, and the rate between the area of the flow cross-section of the air outlet of the blowpipe and the area of the flow cross-section of the flow-through area at the position of the fan is greater than or equal to 0.8.