JPWO2006126408A1 - Centrifugal blower and air conditioner using the same - Google Patents

Abstract

The centrifugal blower includes an impeller including a plurality of blades provided between the shroud and the main plate, and forms a shroud side end on the blade leading edge side into a curved surface, and a pressure surface side of the curved end. When the radius of curvature of R1 is R1 and the radius of curvature on the suction surface side is R2, R1 <R2.

Description

  The present invention relates to a centrifugal blower and an air conditioner, and more particularly to a blower having an improved blade leading edge / shroud side shape and an air conditioner using the same.

  In general, a turbo fan is often attached to 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 includes an impeller, and a heat exchanger is provided around the centrifugal blower.

  The impeller includes 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. Such centrifugal blowers generally have a problem of high noise level and low fan efficiency.

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. 2003-279061). However, in the one described in Japanese Patent Laid-Open No. 2003-279061, as shown in FIGS. 9 and 10, the blade 31 has a shape of an R portion (curved end portion) of the shroud side end portion on the blade leading edge 31 a side. The radius of curvature R ₃ on the pressure surface side and the radius of curvature R ₄ on the suction surface side are equal (R ₃ = R ₄ ), and the sucked air is separated at the tip of the suction surface side blade (R ₄ portion). The fan efficiency was low because peeling on the suction side increased.

  Also, for the purpose of low noise and high efficiency, the blade thickness of all or part of the impeller is formed so as to gradually increase from the shroud to the main plate, and the blade interval between each blade is An impeller of a centrifugal blower that is gradually narrowed from the shroud toward the main plate has been proposed (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, becomes shorter, the air inflow area becomes smaller than that on the shroud side, and the air volume decreases.

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

  It is another object of the present invention to provide a high efficiency air conditioner using a centrifugal fan with high fan efficiency.

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 opposite to the main plate, and the shroud and the main plate. An impeller comprising a plurality of blades provided, the shroud side end on the blade leading edge side is formed into a curved surface, and the radius of curvature on the pressure surface side of the curved end is R ₁ , the suction surface When the radius of curvature on the side is R ₂ , R ₁ <R ₂ is satisfied.

Further, when the thickness of the blade is t, the relationship of R ₁ <R ₂ <t may be satisfied.

Further, in the 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 ₁ and the shroud side thickness is t ₂ , 1 <t ₂ / t ₁ ≦ 1.7 may be satisfied.

  Furthermore, an air conditioner according to the present invention includes a main plate having a boss provided with a motor rotation shaft mounting hole, a shroud arranged opposite to the main plate, and a plurality of shrouds provided between the shroud and the main plate. It has a centrifugal blower having an impeller composed of a blade, and a heat exchanger arranged on the outer peripheral portion of the centrifugal blower.

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

The longitudinal cross-sectional view of the air conditioner which concerns on this invention. The top view of the impeller used for the centrifugal blower which concerns on this invention. The longitudinal cross-sectional view of the impeller along the III-III line of FIG. The conceptual diagram which shows the shroud side edge part of the front edge side of the braid | blade used for the centrifugal blower which concerns on this invention. The perspective view of the braid | blade used for the centrifugal blower which concerns on this invention. The conceptual diagram which shows the air flow at the time of use of the braid | blade used for the centrifugal blower which concerns on this invention. The result of a static pressure and fan efficiency measurement test using the centrifugal blower according to the present invention. The thickness ratio of a blade using the centrifugal blower which concerns on this invention, and a result figure of a static pressure ratio measurement test. The conceptual diagram which shows the front-end | tip part of the braid | blade used for the conventional centrifugal blower. The conceptual diagram which shows the air flow at the time of use of the braid | blade used for the centrifugal blower which concerns on this 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 an actual mounting state.

  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, and a fan motor 3 and blades are provided in the casing 2. A centrifugal blower 20 composed of a car 21 is provided. That is, the fan motor 3 is attached to the central portion of the upper bottom of the housing 2 via the motor base 4, and the impeller 21 is attached to the rotation 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 a heat exchanger is disposed above the centrifugal blower 20 so as to surround the centrifugal blower 20. 7 is arranged. The lower open end of the suction bell mouth 5 serves as an air suction port, and a filter 8 is attached thereto. The outside of the heat exchanger 7 is a blower passage 10, and the lower surface portion is a blower outlet 11. And the frame-shaped front panel 12 is mounted | worn with the opening part of the housing | casing of an air conditioner. The air conditioner 1 is suspended and fixed to a beam or the like by a mounting bracket 13 or the like.

  As shown in FIGS. 2 and 3, the impeller 21 includes a main plate 24 having a boss 22 provided with a motor rotating shaft mounting hole, and a hub 23 provided on an outer peripheral portion of the boss 22, and the main plate. 24, a plurality of blades 25 provided in the circumferential direction, and a shroud 26 disposed to face the main plate 24 with the blades 25 interposed therebetween.

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 25 a side of the blade 25 is such that the radius of curvature on the pressure surface 25 b side is R ₁ , and the suction surface 25 c side. Where R _{2 is} the radius of curvature and t is the thickness of the blade 25, the relationship of R ₁ <R ₂ <t is established over the entire shroud side end portion on the front edge 25 a side of the blade 25, that is, the entire suction side. Is set to

By configuring in this way, the sucked air is reduced in separation at the suction surface side end portion (R ₂ portion) of the blade 25 as shown in FIGS. Separation was suppressed, and as shown in FIG. 7, the static pressure was increased and the fan efficiency was improved. In particular, fan efficiency in a large air volume (high rotation speed) region is improved, and the fan operation range can be expanded.

  Further, as shown in FIG. 5, the thickness of the entire blade 25 gradually increases from the main plate 24 side to the shroud 26 side, where the main plate side thickness is t1 and the shroud side thickness is t2. 1 <t2 / t1 ≦ 1.7. In particular, it is preferable to satisfy 1 <t2 / t1 ≦ 1.5. As a result, the blade 25 has a space between the blades on the main plate 24 side, which is the mainstream of the wind, that is, the space between the suction surface of the blade located in the front and the pressure surface of the blade located in the rear is the blades on the shroud 26 side. It becomes larger than the interval between. 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. Furthermore, the inflow area on the shroud 26 side that is easily peeled is reduced, and peeling on the shroud 26 side can be reduced.

  Thereby, as shown in FIG. 8, the inflow of the air flow becomes smooth, the static pressure increases, 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 is exchanged by the heat exchanger 7, and then the arrow passes through the blower passage 10 and the outlet 11. Blows out in the B direction. As a result, indoor air conditioning is performed by the ceiling cassette type air conditioner.

In this air conditioning process, the air sucked through the suction bell mouth 5 is energized by the blade 25 and is blown out of the impeller 21 at an increased flow velocity. Further, 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 the negative radius of curvature R ₁ on the positive pressure surface 25b side. When the radius of curvature on the pressure surface 25c side is R ₂ and the thickness of the blade 25 is t, the relation of R ₁ <R ₂ <t is established over the entire suction side, and therefore particularly in the large air volume (high rotation speed) region. As the static pressure increases, the fan efficiency improves and the fan operating range can be expanded.

  Further, as shown in FIG. 5, the thickness of the entire blade 25 gradually increases from the main plate 24 side to the shroud 26 side, where the main plate side thickness is t1 and the shroud side thickness is t2. Since 1 <t2 / t1 ≦ 1.7, 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. Furthermore, as shown in FIG. 6, peeling on the suction surface side of the shroud 26 that is easily peeled can be greatly reduced. Thereby, inflow of an air flow becomes smooth, a static pressure increases, and fan efficiency improves.

  Therefore, the air conditioner of the present invention incorporating the high fan efficiency centrifugal fan as described above is also highly efficient.

  Test 1: Static pressure and air volume using a centrifugal fan (Example 1) provided with a blade having a shape as shown in FIG. 4 and a centrifugal fan (conventional example 1) having a blade having a shape as shown in FIG. The relationship between air volume and efficiency was investigated.

  The results are shown in FIG. In Example 1, the air volume at the same static pressure increased compared to Conventional Example 1, and it was found that Example 1 was more efficient than Conventional Example 1 at the same air volume.

  Test 2: Centrifugal blower (Example 2) in which the thickness of the blade 25 as shown in FIG. 5 is gradually increased from the main plate 24 side to the shroud 26 side, and conversely, the thickness of the blade 25 is 26 side from the shroud Using a centrifugal blower (conventional example 2) that was gradually thickened toward the main plate 24 side, the relationship between the ratio t2 / t1 of the thickness t1 on the main plate side and the thickness t2 on the shroud side and the static pressure ratio was examined.

  The results are shown in FIG. In Example 2, when t2 / t1 is in the range of 1 to 1.5, the static pressure of Conventional Example 2 is improved to approximately 101.3%, and even in the range of 1 to 1.7, it may exceed 100%. all right.

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

[0002]
[0006]
DISCLOSURE OF THE INVENTION The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a centrifugal fan with high fan efficiency.
[0007]
It is another object of the present invention 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 opposite to the main plate, and the shroud and the main plate. The blade has an impeller composed of a plurality of blades provided, and the shroud side end in the blade height direction on the blade leading edge side is formed in a curved surface, and the curvature radius on the pressure surface side of the curved end is determined. R ₁ , where the radius of curvature on the suction surface side is R ₂ , R ₁ <R ₂ .
[0009]
Further, when the thickness of the blade is t, the relationship of R ₁ <R ₂ <t may be satisfied.
[0010]
Further, in the 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 ₁ and the shroud side thickness is t ₂ , 1 <t ₂ / t ₁ ≦ 1.7 may be satisfied.
[0011]
Furthermore, an air conditioner according to the present invention includes a main plate having a boss provided with a motor rotation shaft mounting hole, a shroud arranged opposite to the main plate, and a plurality of shrouds provided between the shroud and the main plate. And a shroud side end portion in the blade height direction on the blade leading edge side having a curved surface, and a curvature radius on the pressure surface side of the curved end portion is defined as R ₁ . when the radius of curvature of the side was R _2, and having a centrifugal blower in which the R 1 _{<R 2,} a heat exchanger disposed on the outer periphery of the centrifugal fan.
[0012]
According to the centrifugal fan according to the present invention, a centrifugal fan with high fan efficiency can be provided. In addition, a highly efficient air conditioner using such a high fan efficiency centrifugal blower can be provided.
BRIEF DESCRIPTION OF THE DRAWINGS [0013]
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 an impeller taken along line III-III in FIG.
[FIG. 4] The shroud side end portion in the height direction of the leading edge side of the blade used in the centrifugal blower according to the present invention.

[0004]
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 the main plate 24 sandwiching the blade 25 A shroud 26 is provided opposite to the shroud 26.
[0019]
As shown in FIGS. 3 and 4, the shape of the R portion (curved end portion) of the shroud side end portion in the blade height direction on the front edge 25a side of the blade 25 is the radius of curvature on the pressure surface 25b side as R _1. When the radius of curvature on the suction surface 25c side is R ₂ and the thickness of the blade 25 is t, R ₁ <R ₂ <over the entire shroud side end of the blade 25 on the front edge 25a side, that is, the entire suction side. It is set so that the relationship of t holds.
[0020]
By configuring in this way, the sucked air is reduced in separation at the suction surface side end portion (R ₂ portion) of the blade 25 as shown in FIGS. Separation was suppressed, and as shown in FIG. 7, the static pressure was increased and the fan efficiency was improved. In particular, fan efficiency in a large air volume (high rotation speed) region is improved, and the fan operation range can be expanded.
[0021]
Further, as shown in FIG. 5, the thickness of the entire blade 25 gradually increases from the main plate 24 side to the shroud 26 side, where the main plate side thickness is t1 and the shroud side thickness is t2. 1 <t2 / t1 ≦ 1.7. In particular, it is preferable to satisfy 1 <t2 / t1 ≦ 1.5. As a result, the blade 25 has a space between the blades on the main plate 24 side, which is the mainstream of the wind, that is, the space between the suction surface of the blade located in the front and the pressure surface of the blade located in the rear is the blades on the shroud 26 side. It becomes larger than the interval between. 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. Furthermore, the inflow area on the shroud 26 side that is easily peeled 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 increases, and the fan efficiency is improved.
[0023]
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.
[0024]
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.

[0005]
It blows out in the direction of arrow B through the outlet 11. As a result, indoor air conditioning is performed by the ceiling cassette type air conditioner.
[0025]
In this air conditioning process, the air sucked through the suction bell mouth 5 is energized by the blade 25 and is blown out of the impeller 21 at an increased flow velocity. Further, 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 in the blade height direction on the front edge 25a side of the blade 25 is the curvature on the positive pressure surface 25b side. Assuming that the radius is R ₁ , the radius of curvature on the suction surface 25c side is R ₂ , and the thickness of the blade 25 is t, the relationship is R ₁ <R ₂ <t over the entire suction side. The static pressure in the (rotation speed) region increases, fan efficiency improves, and the fan operating range can be expanded.
[0026]
Further, as shown in FIG. 5, the thickness of the entire blade 25 gradually increases from the main plate 24 side to the shroud 26 side, where the main plate side thickness is t1 and the shroud side thickness is t2. Since 1 <t2 / t1 ≦ 1.7, 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. Furthermore, as shown in FIG. 6, peeling on the suction surface side of the shroud 26 that is easily peeled can be greatly reduced. Thereby, inflow of an air flow becomes smooth, a static pressure increases, and fan efficiency improves.
[0027]
Therefore, the air conditioner of the present invention incorporating the high fan efficiency centrifugal fan as described above is also highly efficient.
Example [0028]
Test 1: Static pressure and air volume using a centrifugal fan (Example 1) provided with a blade having a shape as shown in FIG. 4 and a centrifugal fan (conventional example 1) having a blade having a shape as shown in FIG. The relationship between 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 compared to Conventional Example 1, and it was found 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 is gradually increased from the main plate 24 side to the shroud 26 side, and conversely, the thickness of the blade 25 is increased from the shroud to the 26th side. Using a centrifugal blower (conventional example 2) that was gradually thickened toward the main plate 24 side, the relationship between the ratio t2 / t1 of the thickness t1 on the main plate side and the thickness t2 on the shroud side and the static pressure ratio was examined.
[0031]
The results are shown in FIG. In Example 2, t2 / t1 is in the range of 1 to 1.5, and the static pressure of Conventional Example 2 is not affected.

Claims (4)

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 side end on the blade leading edge side is formed into a curved surface, and when the radius of curvature on the pressure side of the curved end is R ₁ and the radius of curvature on the suction side is R ₂ , R ₁ <R ₂ A centrifugal blower characterized by that. The centrifugal blower according to claim 1, wherein when the thickness of the blade is t, the relationship is R ₁ <R ₂ <t. 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 ₁ , and the shroud side thickness is t ₂ , 1 <t ₂ / t ₁ ≦ 1.7 The centrifugal blower according to claim 1.   A centrifugal fan having 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 having a heat exchanger disposed on the outer peripheral portion of the centrifugal blower.

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