Cross flow fan and indoor unit of air-conditioning apparatus

Patent metadata

Field	Value
Publication number	US-9759220-B2
Application number	US-201113993392-A
Country	US
Kind code	B2
Filing date	Dec 12, 2011
Priority date	Dec 24, 2010
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

An impeller element includes a plurality of blades disposed along an outer circumference of a circular support plate. Each blade is divided into a plurality of blade sections in a rotational axis direction. At least one of the divided blade sections as a long-chord blade section is configured such that a chord as a line segment connecting a blade outer-circumferential edge and a blade inner-circumferential edge of the blade in a cross section perpendicular to a rotational axis of the blade has a greater length than a chord of another one of the blade sections as a short-chord blade section. The blade inner-circumferential edge of the at least one long-chord blade section having the longer chord protrudes toward the inner circumferential side, relative to the blade inner-circumferential edge of the at least other one of the blade sections as the short-chord blade section having the shorter chord.

First claim

The invention claimed is:

1. A cross flow fan comprising:
an impeller that includes a plurality of impeller elements each including a plurality of blades disposed along an outer circumference of a circular support plate, the plurality of impeller elements being fixed to each other in a direction of a rotational axis passing through a center of the support plate;
wherein each of the blades is divided into a plurality of blade sections in the rotational axis direction;
wherein at least one of the divided blade sections is a long-chord blade section whose chord has a length greater than a length of a chord of at least another one of the blade sections, the chord being a line segment connecting a blade outer-circumferential edge and a blade inner-circumferential edge of each of the blades in a cross section perpendicular to the rotational axis of the blades;
wherein at least two of the divided blade sections are short-chord blade sections whose chords have lengths less than a length of the chord of the long-chord blade section, the at least two blade sections being located at opposite ends of each of the blades in the direction of the rotational axis;
wherein the blade inner-circumferential edge of the long-chord blade section protrudes toward an inner circumferential side, relative to the blade inner-circumferential edges of the short-chord blade sections, and
wherein a long-chord length of the long-chord blade section at an interface between the long-chord blade section and the short-chord blade section is longer than a short-chord length of the short-chord blade section at the interface between the long-chord blade section and the short-chord blade section.

2. The cross flow fan of claim 1 , wherein the long-chord blade section is located at least near a center of each of the blades in the rotational axis direction.

3. The cross flow fan of claim 1 , wherein a plurality of recesses are provided at the blade inner-circumferential edge of at least one of the blade sections.

4. The cross flow fan of claim 1 , wherein, at the blade inner-circumferential edge, an inter-blade-section smoothening section is provided at a stepped portion between two adjacent blade sections having chords of different lengths, the inter-blade-section smoothing section having a chord of a length between lengths of the respective chords of the two blade sections.

5. The cross flow fan of claim 1 , wherein: in a cross section perpendicular to the rotational axis of the blades, blade outer-circumferential edges of all the blades of each of the impeller elements are located on an outer diameter line of a same diameter having a center at a position of the rotational axis; a center line between a blade pressure surface as a front surface and a blade pressure suction surface as a rear surface in a rotational direction of the blades is defined as a camber line; and, when an angle formed by the outer diameter line and the camber line is defined as an outlet angle, the long-chord blade section has the outlet angle greater than that of each of the short-chord blade sections.

6. An air-conditioning apparatus comprising the cross flow fan of claim 1 .

7. The cross flow fan of claim 1 ,
wherein the blade inner-circumferential edge is formed of first line segments in the short-chord blade sections, and a second line segment in the long-chord blade section; and
wherein the first line segments are discontinuous with respect to the second line segments.

8. The cross flow fan of claim 7 ,
wherein the first line segment is a straight line.

9. The cross flow fan of claim 7 ,
wherein the second line segments are straight lines.

10. A cross flow fan comprising:
an impeller that includes a plurality of impeller elements each including a plurality of blades disposed along an outer circumference of a support plate, the plurality of impeller elements being fixed to each other in a direction of a rotational axis passing through a center of the support plate;
wherein each of the blades is divided into a plurality of blade sections in the rotational axis direction;
wherein at least one of the divided blade sections is a long-chord blade section whose chord has a length greater than a length of a chord of at least another one of the blade sections, the chord being a line segment connecting a blade outer-circumferential edge and a blade inner-circumferential edge of each of the blades in a cross section perpendicular to the rotational axis of the blades;
wherein the blade inner-circumferential edge of the long-chord blade section protrudes toward an inner circumferential side, relative to the blade inner-circumferential edge of the at least another one of the blade sections as a short-chord blade section having a shorter chord;
wherein a plurality of recesses are provided at the blade inner-circumferential edge of at least one of the blade sections, and
wherein a long-chord length of the long-chord blade section at an interface between the long-chord blade section and the short-chord blade section is longer than a short-chord length of the short-chord blade section at the interface between the long-chord blade section and the short-chord blade section.

11. A cross flow fan comprising:
an impeller that includes a plurality of impeller elements each including a plurality of blades disposed along an outer circumference of a support plate, the plurality of impeller elements being fixed to each other in a direction of a rotational axis passing through a center of the support plate;
wherein each of the blades is divided into a plurality of blade sections in the rotational axis direction;
wherein at least one of the divided blade sections is a long-chord blade section whose chord has a length greater than a length of a chord of at least another one of the blade sections, the chord being a line segment connecting a blade outer-circumferential edge and a blade inner-circumferential edge of each of the blades in a cross section perpendicular to the rotational axis of the blades;
wherein the blade inner-circumferential edge of the long-chord blade section protrudes toward an inner circumferential side, relative to the blade inner-circumferential edge of the at least another one of the blade sections as a short-chord blade section having a shorter chord;
wherein, in a cross section perpendicular to the rotational axis of the blades, the blade outer-circumferential edges of all the blades of the impeller element are located on an outer diameter line of a same diameter having a center at a position of the rotational axis; a center line between a blade pressure surface as a front surface and a blade pressure suction surface as a rear surface in a rotational direction of the blade is defined as a camber line; and, when an angle formed by the outer diameter line and the camber line is defined as an outlet angle, the long-chord blade section has the outlet angle greater than that of the short-chord blade sections, and
wherein a long-chord length of the long-chord blade section at an interface between the long-chord blade section and the short-chord blade section is longer than a short-chord length of the short-chord blade section at the interface between the long-chord blade section and the short-chord blade section.

12. An air-conditioning apparatus comprising:
an air inlet that suctions indoor air;
an air outlet that blows the indoor air suctioned through the air inlet into a room; and
a cross flow fan that blows the indoor air from the air inlet to the air outlet; wherein the cross flow fan includes an impeller that includes a plurality of impeller elements each including a plurality of blades disposed along an outer circumference

Assignees

• Tadokoro Takahide
• Ikeda Takashi
• Hamada Shingo
• Shirota Mitsuhiro
• Mitsubishi Electric Corp

Inventors

• Tadokoro Takahide
• Ikeda Takashi
• Hamada Shingo
• Shirota Mitsuhiro

Classifications

• F04D29/283

  rotors of the squirrel-cage type · CPC title

• F04D17/04 Primary

  of transverse-flow type · CPC title

• F04D29/30

  Vanes · CPC title

• F24F1/0018

  characterised by fans (with secondary air induced by injector action of the primary air F24F1/01) · CPC title

• F04D29/665

  by means of resonance chambers or interference · CPC title