IMPELLER AND CENTRIFUGAL FAN WITH SAME

Abstract

A centrifugal fan includes a frame and an impeller. The impeller is disposed within the frame. The impeller includes a hub, a first blade group and a second blade group. The hub includes a center part, an inclined part and a connection part. The first blade group is connected with the connection part of the hub. The second blade group is disposed on the inclined part of the hub. There is a first distance between the second blade group and the first blade group. There is a second distance between the second blade group and the center part of the hub.

Claims

1. An impeller, comprising: a hub comprising a center part, an inclined part and a connection part; a first blade group connected with the connection part of the hub; and a second blade group disposed on the inclined part of the hub, wherein there is a first distance between the second blade group and the first blade group, and there is a second distance between the second blade group and the center part of the hub.

2. The impeller according to claim 1, wherein the inclined part is arranged between the center part and the connection part, and the inclined part has an incline that is extended downwardly from the center part to the connection part, and an end of the inclined part is connected with the connection part.

3. The impeller according to claim 1, wherein the first distance is in a range between 3 mm and 4 mm, and the second distance is in a range between 3 mm and 4 mm.

4. The impeller according to claim 1, wherein the first distance is equal to the second distance, and both of the first distance and the second distance are 3.5 mm.

5. The impeller according to claim 1, wherein the second blade group is integrally formed with the hub, and the second blade group is protruded upwardly from the inclined part of the hub.

6. The impeller according to claim 1, wherein the first blade group comprises plural forwardly-inclined blades, and the second blade group comprises plural backwardly-inclined blades.

7. The impeller according to claim 6, wherein a blade density of the plural forwardly-inclined blades of the first blade group is larger than a blade density of the plural backwardly-inclined blade of the second blade group.

8. The impeller according to claim 7, wherein a gap between every two adjacent forwardly-inclined blades of the first blade group is in a range between 8 mm and 12 mm, and a gap between every two adjacent backwardly-inclined blades of the second blade group is in a range between 22 mm and 26 mm.

9. The impeller according to claim 8, wherein the gap between every two adjacent forwardly-inclined blades of the first blade group is 10 mm, and the gap between every two adjacent backwardly-inclined blades of the second blade group is 24 mm.

10. The impeller according to claim 1, wherein a height of the second blade group is smaller than a height of the first blade group.

11. The impeller according to claim 10, wherein the height of the first blade group is in a range between 13 mm and 14 mm, and the height of the second blade group is in a range between 11 mm and 12 mm.

12. The impeller according to claim 11, wherein the height of the first blade group is 13.4 mm, and the height of the second blade group is 11.4 mm.

13. The impeller according to claim 10, wherein there is a height difference between the first blade group and the second blade group, and the height difference is in a range between 1 mm and 3 mm.

14. The impeller according to claim 13, wherein the height difference is 2 mm.

15. A centrifugal fan, comprising: a frame; and an impeller disposed within the frame, wherein the impeller comprises: a hub comprising a center part, an inclined part and a connection part; a first blade group connected with the connection part of the hub; and a second blade group disposed on the inclined part of the hub, wherein there is a first distance between the second blade group and the first blade group, and there is a second distance between the second blade group and the center part of the hub.

16. The centrifugal fan according to claim 15, wherein the second blade group is integrally formed with the hub, and the second blade group is protruded upwardly from the inclined part of the hub.

17. The centrifugal fan according to claim 15, wherein the first blade group comprises plural forwardly-inclined blades, and the second blade group comprises plural backwardly-inclined blades, wherein a blade density of the plural forwardly-inclined blades of the first blade group is larger than a blade density of the plural backwardly-inclined blade of the second blade group.

18. The centrifugal fan according to claim 15, wherein a height of the second blade group is smaller than a height of the first blade group.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 is a schematic perspective view illustrating the outer appearance of a centrifugal fan according to an embodiment of the present invention;

[0029] FIG. 2 is a schematic perspective view illustrating the inner structure of the centrifugal fan of FIG. 1;

[0030] FIG. 3A is a schematic cutaway view illustrating the impeller of the centrifugal fan as shown in FIG. 2; and

[0031] FIG. 3B is a schematic cross-sectional view illustrating the impeller of FIG. 3A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0032] The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. In the following embodiments and drawings, the elements irrelevant to the concepts of the present invention are omitted and not shown.

[0033] FIG. 1 is a schematic perspective view illustrating the outer appearance of a centrifugal fan according to an embodiment of the present invention. FIG. 2 is a schematic perspective view illustrating the inner structure of the centrifugal fan of FIG. 1. As shown in FIGS. 1 and 2, the fan is a centrifugal fan 1. The centrifugal fan 1 comprises a frame 10 and an impeller 11. The impeller 11 is disposed within the frame 10. The frame 10 has an inlet 101 and an outlet 102. During operation of the centrifugal fan 1, the ambient airflow is inhaled into the inlet 101, driven to a channel 12 by the impeller 11 and exited from the outlet 102.

[0034] As shown in FIG. 2, the impeller 11 comprises a hub 110, a first blade group 111 and a second blade group 112. The blades of the first blade group 111 are disposed on a periphery region of the hub 12. The blades of the second blade group 112 are disposed on the hub 12. In addition, a motor (not shown) is installed within the hub 110 for providing motive power to the centrifugal fan 1. As the hub 110 is driven to rotate by the motor, the blades of the first blade group 111 and the blades of the second blade group 112 are synchronously rotated to increase the speed of inhaling the airflow. Moreover, the airflow is exited from the outlet 102 through the channel 12.

[0035] FIG. 3A is a schematic cutaway view illustrating the impeller of the centrifugal fan as shown in FIG. 2. As shown in FIG. 3A, the hub 110 comprises a center part 110a, an inclined part 110b and a connection part 110c. In this embodiment, the hub 110 is a disk-type structure. The center part 110a is located at the center position of the hub 110. The motor (not shown) is disposed under the center part 110a. The center part 110a is cup-shaped. The inclined part 110b is arranged between the center part 110a and the connection part 110c. Moreover, the inclined part 110b has an incline that is extended downwardly from the center part 110a to the connection part 110c. An end of the inclined part 110b is connected with the connection part 110c. The connection part 110c is connected with the first blade group 111. In an embodiment, the first blade group 111 is assembled with the hub 110 through the connection part 110c by engagement. In another embodiment, the first blade group 111 is integrally formed with the connection part 110c. That is, the way of connecting the first blade group 111 and the connection part 110c is not limited to the above embodiment and may be varied according to the practical requirements. The second blade group 112 is disposed on the inclined part 110b. Preferably, the second blade group 112 is integrally formed with the inclined part 110b of the hub 110. Moreover, the second blade group 112 is protruded upwardly from the inclined part 110b.

[0036] FIG. 3B is a schematic cross-sectional view illustrating the impeller of FIG. 3A. The operating principle of the centrifugal fan 1 will be described with reference to FIGS. 3A and 3B.

[0037] Please refer to FIG. 3A. The blades of the first blade group 111 are disposed on the periphery region of the hub 110. Moreover, the first blade group 111 comprises plural forwardly-inclined blades 111a. The blades of the second blade group 112 are disposed on the inclined part 110b of the hub 110. Moreover, the second blade group 112 comprises plural backwardly-inclined blades 112a. That is, the forwardly-inclined blades 111a of the first blade group 111 and the backwardly-inclined blades 112a of the second blade group 112 are inclined in opposite directions. The backwardly-inclined blades 112a of the second blade group 112 can increase the impedance of the centrifugal fan 1.

[0038] Please refer to FIG. 3B. There is a first distance d1 between the rear edge of the backwardly-inclined blade 112a of the second blade group 112 and the front edge of the forwardly-inclined blade 111a of the first blade group 111. That is, the second blade group 112 is separated from the first blade group 111, and the blades of the second blade group 112 and the blades of the first blade group 111 are not interlaced. Moreover, there is a second distance d2 between the front edge of the backwardly-inclined blade 112a of the second blade group 112 and the edge of the center part 110a of the hub 110. That is, the second blade group 112 is separated from the center part 110a of the hub 110. In this embodiment, the second blade group 112 is separated from the center part 110a of the hub 110, and the second blade group 112 is separated from the first blade group 111. In an embodiment, the first distance d1 is equal to the second distance d2. For example, both of the first distance d1 and the second distance d2 are in the range between 3 mm and 4 mm. Preferably, both of the first distance d1 and the second distance d2 are 3.5 mm.

[0039] Please refer to FIG. 3A again. In this embodiment, the blade density of the forwardly-inclined blades 111a of the first blade group 111 is larger than the blade density of the backwardly-inclined blades 112a of the second blade group 112. For example, the first blade group 111 comprises 71 forwardly-inclined blades 111a, and the second blade group 112 comprises 31 backwardly-inclined blades 112a. Since the forwardly-inclined blades 111a of the first blade group 111 are densely arranged, the noise is reduced. Moreover, since the backwardly-inclined blades 112a of the second blade group 112 are inclined in the opposite direction, the impedance of the centrifugal fan 1 is increased and the overall performance of the centrifugal fan 1 is enhanced. Moreover, a gap d4 between every two adjacent forwardly-inclined blades 111a of the first blade group 111 is in the range between 8 mm and 12 mm, and preferably 10 mm. Moreover, a gap d5 between every two adjacent backwardly-inclined blades 112a of the second blade group 112 is in the range between 22 mm and 26 mm, and preferably 24 mm.

[0040] Please refer to FIG. 3B again. In this embodiment, the height of the center part 110a of the hub 110 is larger than the height of the first blade group 111 and the height of the second blade group 112. Moreover, the height of the first blade group 111 is larger than the height of the second blade group 112. In an embodiment, the height of the first blade group 111 is in the range between 13 mm and 14 mm, and preferably 13.4 mm. Moreover, the height of the second blade group 112 is in the range between 11 mm and 12 mm, and preferably 11.4 mm. There is a height difference d3 between the first blade group 111 and the second blade group 112. The height difference d3 is in the range between 1 mm and 3 mm, and preferably 2 mm.

[0041] From the above descriptions, the present invention provides an impeller and a centrifugal fan with the impeller. The impeller of the present invention is specially designed. The second blade group is integrally formed with the inclined part of the hub in order to increase the impedance of the centrifugal fan and reduce the system impedance. Consequently, the centrifugal fan is suitably used in the high system impedance condition. Moreover, since the forwardly-inclined blades of the first blade group are densely arranged, the noise is reduced. More especially, the layout space of the centrifugal fan is not increased. Consequently, the overall performance of the centrifugal fan is enhanced, the system impedance is reduced and the noise is reduced.

[0042] While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.