Centrifugal impeller and centrifugal fan comprising the same

1. A device, comprising:

a wheel cover comprising an air inlet;

a wheel disc; and

a plurality of blades disposed between the wheel cover and the wheel disc; wherein:

the wheel cover and the wheel disc each comprise a sheet metal, and the plurality of blades comprises a composite material;

the wheel disc comprises a central part and a motor mounting base disposed on the central part;

every two adjacent blades form an air channel comprising an air outlet;

the plurality of blades each comprises a metal frame and a plastic shell disposed on the metal frame;

two ends of the metal frame are connected to the wheel cover and the wheel disc, respectively;

a thickness of the plastic shell is variable; the metal frame is integrated with the plastic shell through injection molding;

the metal frame comprises a plurality of sheet metals having equal thickness; the metal frame comprises a central camber line A; a cross section of the plastic shell comprises a first curve and a second curve; and the first curve and the second curve are symmetrical or asymmetrical with respect to the central camber line A; and

the plastic shell is wrapped around a part of a main body of the metal frame close to the air inlet, and rest of the main body is uncovered.

2. The device of claim 1 , wherein a relationship between a maximum thickness H max of the plastic shell and a thickness Ho of the metal frame is as follows: Ho≤H max ≤8Ho.

3. The device of claim 1 , wherein the main body of the metal fame comprises a first end face and a second end face, and the metal frame comprises a plurality of locating blocks protruding from the first end face and the second end face;

the wheel cover comprises a plurality of first mounting holes, and the wheel disc comprises a plurality of second mounting holes; the plurality of locating blocks on the first end face and the second end face are disposed in the plurality of first mounting holes and the plurality of second mounting holes, respectively, whereby the wheel cover, the wheel disc, and the metal frame are fixedly connected to each other.

4. A centrifugal fan, comprising: the device of claim 1 , a motor, and a volute; wherein the volute comprises an air inlet, a cavity, and an air channel; the centrifugal impeller is disposed in the cavity, and the air inlet and the air channel communicate with the cavity; and the centrifugal impeller is disposed on the motor and driven by the motor.

5. A device, comprising:

a wheel cover comprising an air inlet;

a wheel disc; and

a plurality of blades disposed between the wheel cover and the wheel disc; wherein:

the wheel cover and the wheel disc each comprise a sheet metal, and the plurality of blades comprises a composite material;

the wheel disc comprises a central part and a motor mounting base disposed on the central part;

every two adjacent blades form an air channel comprising an air outlet;

the plurality of blades each comprises a metal frame and a plastic shell disposed on the metal frame;

two ends of the metal frame are connected to the wheel cover and the wheel disc, respectively;

a thickness of the plastic shell is variable; the metal frame is integrated with the plastic shell through injection molding;

the plastic shell is wrapped around at least a part of the metal frame;

the metal frame comprises a plurality of sheet metals having equal thickness; the metal frame comprises a central camber line A; a cross section of the plastic shell comprises a first curve and a second curve; and the first curve and the second curve are symmetrical or asymmetrical with respect to the central camber line A;

the central camber line A is a circular arc with a chord line L; and the following equation is satisfied:

y

=

[

(

0.5

sin

⁢

⁢

θ

2

)

2

-

(

x

-

0.5

)

2

]

1

2

-

0.5

tan

⁢

⁢

θ

2

;

θ refers to a bending angle of the central camber line A, and x and y refer to a coordinate value of a point on the central camber line A.

6. The device of claim 5 , wherein a coordinate value of a point on the first curve and the second curve are determined as follows:

the

⁢

⁢

first

⁢

⁢

curve

⁢

:

{

x

u

=

x

-

y

ex

⁢

sin

⁢

⁢

φ

x

y

u

=

y

+

y

ex

⁢

cos

⁢

⁢

φ

x

;

⁢

the

⁢

⁢

second

⁢

⁢

curve

⁢

:

⁢

⁢

{

x

1

=

x

+

y

ex

⁢

sin

⁢

⁢

φ

x

y

1

=

y

-

y

ex

⁢

cos

⁢

⁢

φ

x

;

⁢

where

⁢

⁢

φ

=

tan

-

1

⁢

dy

dx

;

φ x is an included angle between a tangent at a point on the central camber line A and an x-axis; and

x and y refer to a coordinate value of a point on the central camber line A;

x u and y u refer to a coordinate value of a point on the first curve; and

x 1 and y 1 refer to a coordinate value of a point on the second curve.

7. A device, comprising:

a wheel cover comprising an air inlet;

a wheel disc; and

a plurality of blades disposed between the wheel cover and the wheel disc; wherein:

the wheel cover and the wheel disc each comprise a sheet metal, and the plurality of blades comprises a composite material;

the wheel disc comprises a central part and a motor mounting base disposed on the central part;

every two adjacent blades form an air channel comprising an air outlet;

the plurality of blades each comprises a metal frame and a plastic shell disposed on the metal frame;

two ends of the metal frame are connected to the wheel cover and the wheel disc, respectively;

a thickness of the plastic shell is variable; the metal frame is integrated with the plastic shell through injection molding;

the plastic shell is wrapped around at least a part of the metal frame;

the metal frame comprises a plurality of sheet metals having equal thickness; the metal frame comprises a central camber line A; a cross section of the plastic shell comprises a first curve and a second curve; and the first curve and the second curve are symmetrical or asymmetrical with respect to the central camber line A;

the central camber line A comprises a plurality of circular arcs, with a chord line L; and the following equation is satisfied:

x

≤

0.45

,

y

=

[

(

0.45

sin

⁡

(

0.6

⁢

⁢

θ

)

)

2

-

(

x

-

0.45

)

2

]

1

2

-

0.45

tan

⁡

(

0.6

⁢

θ

)

;

x

>

0.45

,

y

=

[

(

0.55

sin

⁡

(

0.4

⁢

⁢

θ

)

)

2

-

(

x

-

0.45

)

2

]

1

2

-

0.55

tan

⁡

(

0.4

⁢

θ

)

;

θ refers to a bending angle of the central camber line A, and x and y refer to a coordinate value of a point on the central camber line A.

8. The device of claim 7 , wherein a coordinate value of a point on the first curve and the second curve are determined as follows:

the

⁢

⁢

first

⁢

⁢

curve

⁢

:

{

x

u

=

x

-

y

ex

⁢

sin

⁢

⁢

φ

x

y

u

=

y

+

y

ex

⁢

cos

⁢

⁢

φ

x

;

⁢

the

⁢

⁢

second

⁢

⁢

curve

⁢

:

⁢

⁢

{

x

1

=

x

+

y

ex

⁢

sin

⁢

⁢

φ

x

y

1

=

y

-

y

ex

⁢

cos

⁢

⁢

φ

x

;

⁢

where

⁢

⁢

φ

=

tan

-

1

⁢

dy

dx

;

φ x is an included angle between a tangent at a point on the central camber line A and an x-axis; and

x and y refer to a coordinate value of a point on the central camber line A;

x u and y u refer to a coordinate value of a point on the first curve; and

x 1 and y 1 refer to a coordinate value of a point on the second curve.

9. A device, comprising:

a wheel cover comprising an air inlet;

a wheel disc; and

a plurality of blades disposed between the wheel cover and the wheel disc; wherein:

the wheel cover and the wheel disc each comprise a sheet metal, and the plurality of blades comprises a composite material;

the wheel disc comprises a central part and a motor mounting base disposed on the central part;

every two adjacent blades form an air channel comprising an air outlet;

the plurality of blades each comprises a metal frame and a plastic shell disposed on the metal frame;

two ends of the metal frame are connected to the wheel cover and the wheel disc, respectively;

a thickness of the plastic shell is variable; the metal frame is integrated with the plastic shell through injection molding;

the plastic shell is wrapped around at least a part of the metal frame;

the metal frame comprises a plurality of sheet metals having equal thickness; the metal frame comprises a central camber line A; a cross section of the plastic shell comprises a first curve and a second curve; and the first curve and the second curve are symmetrical or asymmetrical with respect to the central camber line A;

the central camber line A is a parabola with a chord line L, and the following equation is satisfied:

1

y

=

cot

⁡

(

0.6

⁢

θ

)

x

-

cot

⁡

(

0.4

⁢

θ

)

1

-

x

;

where θ refers to a bending angle of the central camber line A, and x and y refer to a coordinate value of a point on the central camber line A.

10. The device of claim 9 , wherein a coordinate value of a point on the first curve and the second curve are determined as follows:

the

⁢

⁢

first

⁢

⁢

curve

⁢

:

{

x

u

=

x

-

y

ex

⁢

sin

⁢

⁢

φ

x

y

u

=

y

+

y

ex

⁢

cos

⁢

⁢

φ

x

;

⁢

the

⁢

⁢

second

⁢

⁢

curve

⁢

:

⁢

⁢

{

x

1

=

x

+

y

ex

⁢

sin

⁢

⁢

φ

x

y

1

=

y

-

y

ex

⁢

cos

⁢

⁢

φ

x

;

⁢

where

⁢

⁢

φ

=

tan

-

1

⁢

dy

dx

;

φ x is an included angle between a tangent at a point on the central camber line A and an x-axis; and

x and y refer to a coordinate value of a point on the central camber line A;

x u and y u refer to a coordinate value of a point on the first curve; and

x 1 and y 1 refer to a coordinate value of a point on the second curve.