WO2006126408A1 - Centrifugal blower and air conditioner using the same - Google Patents

Abstract

A centrifugal blower having a bladed wheel with blades arranged between a shroud and a main plate. A shroud-side end section on the front edge side of a blade is formed into a curved surface, and the centrifugal blower satisfies R1 < R2, where R1 is the curvature radius on the positive pressure side of the curved end section, and R2 is the curvature radius on the negative pressure side.

Description

 Specification

 Centrifugal blower and air conditioner using the same

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a centrifugal blower and an air conditioner, and more particularly, to a blower with an improved blade front edge shape on the shroud side and an air conditioner using the same.

 Background art

 In general, a ceiling fan is often mounted on a ceiling cassette type air conditioner or the like.

 This air conditioner includes a housing whose lower end is opened, and an electric centrifugal blower is attached to the center of the housing. This centrifugal blower is equipped with an impeller, and a heat exchanger is provided around the centrifugal blower.

 [0003] The impeller also has a main plate having a boss provided with a motor rotating shaft mounting hole, a shroud disposed opposite to the main plate, and a plurality of blades provided between the shroud and the main plate. ing. Such centrifugal blowers generally have the problem of high noise levels and low fan efficiency.

 [0004] Therefore, a centrifugal blower has been proposed in which the arrangement of the blade length, the blade pitch, etc. is improved to achieve low noise and high efficiency (Japanese Patent Laid-Open No. 2003-290661). However, in the one described in Japanese Patent Laid-Open No. 2003-290661, as shown in FIGS. 9 and 10, the blade 31 has an R portion (curved surface shape) at the shroud side end on the blade leading edge 31a side. As for the shape of the edge, the radius of curvature R on the pressure surface side and the radius of curvature R on the suction surface side are equal (R = R), and the sucked air

 3 4 3 4

 Peels off at the tip of the suction side blade (R part), increasing peeling on the suction side

 Four

 As a result, fan efficiency was low.

[0005] Further, for the purpose of reducing noise and increasing efficiency, the blade thickness of all or part of the impeller is formed so as to gradually increase from the shroud toward the main plate, and the mutual blades are mutually connected. There has been proposed an impeller of a centrifugal blower in which the blade interval is gradually narrowed toward the shroud force main plate (Japanese Patent Laid-Open No. 2001-132687). However, in this publication, the distance between the blades on the main plate side, which is the main flow of air, is shortened, the air inflow area is smaller than the shroud side, and the air volume is reduced. [0006] Disclosure of the Invention

 The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a centrifugal fan with high fan efficiency.

[0007] Another object of the present invention is to provide a high-efficiency air conditioner using a centrifugal fan with high fan efficiency.

 [0008] In order to achieve the above-described object, a centrifugal blower according to the present invention includes a main plate having a boss provided with a motor rotation shaft mounting hole, a shroud disposed to face the main plate, and the shroud. It has an impeller comprising a plurality of blades provided between the main plates, the shroud side end on the blade leading edge side is formed in a curved surface, and the curvature radius on the pressure side of the curved end is determined. R, where R is the radius of curvature on the suction side, R <R

 1 2 1 2

 To do.

 [0009] Further, when the thickness of the blade is t, the relationship of R <R <t may be satisfied.

 1 2

[0010] Further, in the above centrifugal blower, when the thickness of the entire blade is gradually increased from the main plate side to the shroud side, the main plate side thickness is t, and the shroud side thickness is t, Zt

 1 2 2 1

≤1.7 may be satisfied.

Furthermore, an air conditioner according to the present invention is provided with a main plate having a boss provided with a motor rotating shaft mounting hole, a shroud disposed to face the main plate, and between the shroud and the main plate. A centrifugal blower having an impeller composed of a plurality of blades, and a heat exchanger disposed on an outer peripheral portion of the centrifugal blower.

[0012] The centrifugal blower according to the present invention can provide a centrifugal fan with high fan efficiency. In addition, a highly efficient air conditioner using such a high fan efficiency centrifugal blower can be provided.

 Brief Description of Drawings

FIG. 1 is a longitudinal sectional view of an air conditioner according to the present invention.

 FIG. 2 is a plan view of an impeller used in a centrifugal blower according to the present invention.

 FIG. 3 is a longitudinal sectional view of the impeller along the line ΠΙ-ΠΙ in FIG.

FIG. 4 shows the shroud side end of the leading edge side of the blade used in the centrifugal blower according to the present invention. FIG.

 FIG. 5 is a perspective view of a blade used in the centrifugal blower according to the present invention.

 FIG. 6 is a conceptual diagram showing an air flow during use of a blade used in a centrifugal blower according to the present invention.

 FIG. 7 is a result of a static pressure and fan efficiency measurement test using the centrifugal fan according to the present invention.

 FIG. 8 is a diagram showing a result of a blade thickness ratio and static pressure ratio measurement test using the centrifugal fan according to the present invention.

 FIG. 9 is a conceptual diagram showing the tip of a blade used in a conventional centrifugal blower.

 FIG. 10 is a schematic diagram showing an air flow when using a blade used in a centrifugal blower according to the present invention.

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an air conditioner according to an embodiment of the present invention will be described with reference to the accompanying drawings.

 In the following description, terms indicating vertical and horizontal directions are used with reference to the accompanying drawings or based on actual mounting conditions.

 As shown in FIG. 1, an air conditioner 1 according to the present invention is, for example, a ceiling cassette type air conditioner, and includes a casing 2 having an open lower end portion. A centrifugal blower 20 comprising a fan motor 3 and an impeller 21 is provided. That is, the fan motor 3 is attached to the center of the upper bottom of the housing 2 via the motor base 4, and the impeller 21 is attached to the rotating shaft of the fan motor 3.

 Further, a suction bell mouth 5 is provided at the lower portion of the centrifugal blower 20, a drain pan 6 is disposed on the outer peripheral portion of the suction bell mouth 5, and the centrifugal blower 20 is surrounded by the upper portion thereof. The heat exchanger 7 is arranged in the front. The lower open end of the suction bell mouth 5 serves as a suction port for air, and a filter 8 is attached here. The outside of the heat exchanger 7 is an air supply passage 10, and the lower surface portion is an air outlet 11. A frame-shaped front panel 12 is attached to the opening of the casing of the air conditioner. The air conditioner 1 is suspended and fixed to a beam or the like by a mounting bracket 13 or the like.

[0018] As shown in Figs. 2 and 3, the impeller 21 is provided with a motor rotating shaft mounting hole. A main plate 24 having a boss 22 and a hub 23 provided on the outer periphery of the boss 22, a plurality of blades 25 provided in the circumferential direction of the main plate 24, and a main plate 24 sandwiching the blade 25 Is provided with a shroud 26 arranged opposite to it.

[0019] As shown in Figs. 3 and 4, the shape of the R portion (curved end portion) of the shroud side end portion on the front edge 25a side of the blade 25 is R, and the radius of curvature on the pressure surface 25b side is R, negative. When the radius of curvature on the pressure surface 25c side is R and the wall thickness of the blade 25 is t, the entire edge of the shroud side of the front edge 25a side of the blade 25

2

 That is, it is set so that the relationship of R <R <t is established over the entire suction side.

 1 2

[0020] With this configuration, the sucked-in air is less separated from the suction surface side end (R portion) of the blade 25 as shown in FIGS. 4 and 6, and the suction surface 25c side of the blade 25 is reduced. Peeling off

 2

 As shown in Fig. 7, static pressure increased and fan efficiency improved. In particular, fan efficiency is improved in a large air volume (high rotation speed) range, and the fan operating range can be expanded.

In addition, as shown in FIG. 5, the thickness of the blade 25 as a whole is gradually increased from the main plate 24 side cover to the shroud 26 side, so that the main plate side thickness is tl and the shroud side thickness is When t2, the relationship of l <t2Ztl≤l. 7 is established. In particular, it is preferable that l <t2Ztl≤l.5. As a result, the blade 25 has a space between the blades on the main plate 24 side, which is the main flow of wind, that is, the distance between the suction surface of the blade located in the front and the pressure surface of the blade located in the rear is on the shroud 26 side. It becomes larger than the interval between the blades. As a result, the air inflow area on the main plate 24 side becomes larger than the air inflow area on the shroud 26 side, and the inflow resistance on the main plate 24 side, which is the main flow of wind, can be reduced and the air volume can be increased. In addition, the inflow area force S on the shroud 26 side, which is easy to peel off, is reduced, and peeling on the shroud 26 side can be reduced.

 [0022] Thereby, as shown in FIG. 8, the inflow of the air flow becomes smooth, the static pressure is increased, and the fan efficiency is improved.

 Next, the air conditioning action by the air conditioner according to the present invention and the air blowing action of the centrifugal blower according to the present invention will be described.

As shown in FIG. 1, when the fan motor 3 is energized, the centrifugal blower 20 is rotated, the indoor air is sucked in the direction of arrow A, and heat exchange is performed by the heat exchanger 7. Blows in the direction of arrow B through exit 11. As a result, indoor air conditioning is performed using a ceiling cassette type air conditioner.

In this air conditioning process, the air sucked and sucked through the suction bell mouth 5 is energized by the blade 25, increases the flow velocity, and is blown out of the impeller 21. In addition, in this air blowing process, as shown in FIG. 4, the shape of the R portion (curved end portion) of the shroud side end portion on the front edge side 25a of the blade 25 is R, and the radius of curvature on the pressure surface 25b side is R, negative. When the radius of curvature on the pressure surface 25c side is R and the wall thickness of the blade 25 is t, there is a relationship of R <R t over the entire suction side.

2 1 2

 As a result, the static pressure especially in the large air volume (high rotation speed) region increases, the fan efficiency improves, and the fan operation range can be expanded.

In addition, as shown in FIG. 5, the thickness of the entire blade 25 is gradually increased from the main plate 24 side cover to the shroud 26 side, and the main plate side wall thickness is tl, and the shroud side wall thickness is When t2, the relation of l <t2Ztl≤l.7 is established, so that the inflow resistance on the main plate 24 side, which is the main wind, can be reduced and the air volume can be increased. Furthermore, as shown in FIG. 6, the peeling on the suction surface side of the shell 26, which is easily peeled, can be greatly reduced. As a result, the inflow of airflow is smoothed and the static pressure is increased, improving the fan efficiency.

 [0027] Therefore, the air conditioner of the present invention incorporating the centrifugal fan with high fan efficiency as described above also has high efficiency.

 Example

 [0028] Test 1: Using a centrifugal blower (Example 1) having a blade shape as shown in FIG. 4 and a centrifugal blower (conventional example 1) having a blade shape as shown in FIG. The relationship between pressure and air volume, and air volume and efficiency was investigated.

 [0029] The results are shown in FIG. In Example 1, the air volume at the same static pressure increased as compared with Conventional Example 1, and it was proved that Example 1 was more efficient than Conventional Example 1 at the same air volume.

 [0030] Test 2: Centrifugal blower (Example 2) in which the thickness of the blade 25 as shown in Fig. 5 was gradually increased from the main plate 24 side to the shroud 26 side and the thickness of the blade 25 was reversed. Using a centrifugal blower (conventional example 2) that was gradually thickened from the shroud to the 26th main plate 24 side, the relationship between the ratio t2Zt1 of the main plate side wall thickness 1 to the shroud side wall thickness t2 was examined.

[0031] The results are shown in FIG. In Example 2, when t2Ztl is in the range of 1 to 1.5, the static pressure of Conventional Example 2 is not affected. As a result, it was improved to almost 101.3%, and it was found that the range of 1 to 1.7 exceeded 100%. The centrifugal fan according to the present invention can provide a centrifugal fan with high fan efficiency. In addition, a highly efficient air conditioner using such a high fan efficiency centrifugal blower can be provided.

Claims

Claims [1] A blade comprising a main plate having a boss provided with a motor rotating shaft mounting hole, a shroud disposed opposite to the main plate, and a plurality of blades provided between the shroud and the main plate The shroud end on the blade leading edge side is formed in a curved surface, and the radius of curvature on the pressure surface side of the curved end is set to R.  1. The radius of curvature on the suction side is R  2 and R <R  1 Centrifugal blower characterized by being 2  [2] The relation of R <R tt is satisfied, where t is the thickness of the blade.  1 2  The centrifugal blower described.  [3] When the thickness of the entire blade is gradually increased from the main plate side force to the shroud side, the main plate side thickness is t, and the shroud side thickness is t, Kt Zt≤1.7. Special features 1 2 2 1  The centrifugal fan according to claim 1. [4] A bladed wheel comprising a main plate having a boss provided with a motor rotating shaft mounting hole, a shroud disposed opposite to the main plate, and a plurality of blades provided between the shroud and the main plate. An air conditioner comprising: a centrifugal blower having a heat exchanger disposed on an outer peripheral portion of the centrifugal blower.