MOTOR FAN AND ELECTRIC VACUUM CLEANER

摘要

PROBLEM TO BE SOLVED: To reduce wind noise generated from a motor fan which has a frequency determined by a product of the number of moving blades and the number of revolution. SOLUTION: This motor fan comprises: a centrifugal type impeller 21 having the plural moving blades 22 of swept back type; an air guide 25 having a plurality of stationary blades arranged around the impeller 21; and a prime motor 29 for driving the impeller 21. The wind noise of high frequency can be set in an inaudible range of more than 16 kHz by setting the product of the number of the moving blades and the number of revolution in every second to more than 160000.