Electric blower and electric cleaner with same

1. An electric blower comprising a stator, a rotor rotatably supported inside the stator and rotating on a rotary shaft, a bracket supporting the stator, a rotary fan attached to the rotary shaft, an air guide disposed between the bracket and the rotary fan, and a fan case with an air inlet at its center and covering the air guide and the rotary fan; the air guide comprising:

a partition plate disposed between the bracket and the rotary fan;

a diffuser disposed on an outer periphery of the rotary fan and including a plurality of diffuser vanes;

a partition slope making contact with a bottom face of the diffuser and tilted; and

a guide vane formed on a rear face of the diffuser via the partition plate;

wherein

the diffuser vanes form closed passages, and

passage lengths of the closed passages are set to a first passage length and a second passage length that is different from the first passage length, and

further wherein

|L1−L2|=(λ/2) (2×m−1) (m is integer) is established, where v is a flow rate at a passage outlet, n is a number of revolutions of the rotary fan, z is a number of impellers of the rotary fan, λ is a wavelength of sound at the passage outlet, where λ=v/(n×z) is established, L1 is the first passage length, and L2 is the second passage length.

2. An electric blower comprising a stator, a rotor rotatably supported inside the stator and rotating on a rotary shaft, a bracket supporting the stator, a rotary fan attached to the rotary shaft, an air guide disposed between the bracket and the rotary fan, and a fan case with an air inlet at its center and covering the air guide and the rotary fan; the air guide comprising:

a partition plate disposed between the bracket and the rotary fan;

a diffuser disposed on an outer periphery of the rotary fan and including a plurality of diffuser vanes;

a partition slope making contact with a bottom face of the diffuser and tilted; and

a guide vane formed on a rear face of the diffuser via the partition plate;

wherein

the diffuser vanes form closed passages, and

passage lengths of the closed passages are set to a first passage length and a second passage length that is different from the first passage length, and

further wherein

|L1−L2|=(λ/2) (2×m−1)/k (m and k are integers) is established, where v is a flow rate at a passage outlet, n is a number of revolutions of the rotary fan, z is a number of impellers on the rotary fan, λ is a wavelength of sound at the passage outlet, where λ=v/(n×z) is established, L1 is the first passage length, and L2 is the second passage length.

3. An electric blower comprising a stator, a rotor rotatably supported inside the stator and rotating on a rotary shaft, a bracket supporting the stator, a rotary fan attached to the rotary shaft, an air guide disposed between the bracket and the rotary fan, and a fan case with an air inlet at its center and covering the air guide and the rotary fan; the air guide comprising:

a partition plate disposed between the bracket and the rotary fan;

a diffuser disposed on an outer periphery of the rotary fan and including a plurality of diffuser vanes;

a partition slope making contact with a bottom face of the diffuser and tilted; and

a guide vane formed on a rear face of the diffuser via the partition plate;

wherein

the diffuser vanes form closed passages, and

the diffuser includes a first diffuser vane and a second diffuser vane that has a length different from that of the first diffuser vane,

further wherein

the second diffuser vane has a chipped portion at a side of outlet, and

passage lengths of the closed passages are set to a first passage length and a second passage length that is different from the first passage length.

4. An electric vacuum cleaner equipped with the electric blower of claim 1 .

5. An electric vacuum cleaner equipped with the electric blower of claim 2 .

6. An electric vacuum cleaner equipped with the electric blower of claim 3 .

7. The electric blower of claim 1 , wherein the closed passages include a passage with the first passage length and a passage with the second passage length disposed adjacent to each other with respect to a rotating direction of the rotary fan.

8. The electric blower of claim 2 , wherein the closed passages include a passage with the first passage length and a passage with the second passage length disposed adjacent to each other with respect to a rotating direction of the rotary fan.

9. The electric blower of claim 3 , wherein the closed passages include a passage with the first passage length and a passage with the second passage length disposed adjacent to each other with respect to a rotating direction of the rotary fan.